* Re: [RFC] vfs: skip extra attributes check on removal for symlinks
From: Darrick J. Wong @ 2018-05-01 17:23 UTC (permalink / raw)
To: Luis R. Rodriguez
Cc: viro, linux-fsdevel, linux-api, sandeen, dhowells, tytso, fliu,
jack, jeffm, nborisov, jake.norris, mtk.manpages, linux-xfs,
linux-kernel
In-Reply-To: <20180426234639.12480-1-mcgrof@kernel.org>
On Thu, Apr 26, 2018 at 04:46:39PM -0700, Luis R. Rodriguez wrote:
> Linux filesystems cannot set extra file attributes (stx_attributes as per
> statx(2)) on a symbolic link. To set extra file attributes you issue
> ioctl(2) with FS_IOC_SETFLAGS, *all* ioctl(2) calls on a symbolic link
> yield EBADF.
>
> This is because ioctl(2) tries to obtain struct fd from the symbolic link
> file descriptor passed using fdget(), fdget() in turn always returns no
> file set when a file descriptor is open with O_PATH. As per symlink(2)
> O_PATH and O_NOFOLLOW must *always* be used when you want to get the file
> descriptor of a symbolic link, and this holds true for Linux, as such extra
> file attributes cannot possibly be set on symbolic links on Linux.
>
> Filesystems repair utilities should be updated to detect this as
> corruption and correct this, however, the VFS *does* respect these
> extra attributes on symlinks for removal.
>
> Since we cannot set these attributes we should special-case the
> immutable/append on delete for symlinks, this would be consistent with
> what we *do* allow on Linux for all filesystems.
Ah, ok, so the problem here is that you can't rm an "immutable" symlink
nor can you clear the immutable flag on such a beast, so therefore
ignore the immutable (and append) flags if we're trying to delete a
symlink?
I think we ought to teach the xfs inode verifier to check for
immutable/append symlinks and return error so that we don't end up with
such things in core in the first place, and fix xfs_repair to zap such
things.
That said, for the filesystems that aren't going to check their inodes,
I guess this is a (hackish) way to avoid presenting undeletable gunk in
the fs to the user...
(Were it up to me I'd make a common vfs_check_inode() to reject
struct inode containing garbage that the vfs won't deal with, and teach
the filesystems to use it; but I was shot down when I tried to do that
for negative isize.)
--D
> The userspace utility chattr(1) cannot set these attributes on symlinks
> *and* other special files as well:
>
> # chattr -a symlink
> chattr: Operation not supported while reading flags on b
>
> The reason for this is different though. Refer to commit 023d111e92195
> ("chattr.1.in: Document the compression attribute flags E, X, and ...")
> merged on e2fsprogs v1.28 since August 2002. This commit prevented
> issuing the ioctl() for symlink *and* special files in consideration for
> a buggy DRM driver where issuing lsattr on their special files crashed
> the system. For details refer to Debian bug 152029 [0].
>
> You can craft your own tool to query the extra file attributes with
> the new shiny statx(2) tool, statx(2) will list the attributes if
> they were set for instance on a corrupt filesystem. However statx(2)
> is only used for *querying* -- not for setting the attributes.
>
> If you implement issuing your own ioctl() for FS_IOC_FSGETXATTR or
> FS_IOC_FSSETXATTR on special files (block, char, fifo) it will fail
> returning -1 and errno is set to ENOTTY (Inappropriate ioctl for
> device). The reason for this is different than for symlinks.
> For special files this fails on vfs_ioctl() when the filesystem
> f_op callbacks are not set for these special files:
>
> long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> int error = -ENOTTY;
>
> if (!filp->f_op->unlocked_ioctl)
> goto out;
>
> error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
> if (error == -ENOIOCTLCMD)
> error = -ENOTTY;
> out:
> return error;
> }
>
> The same applies to PF_LOCAL named sockets. Since this varies by
> filesystem for special files, only make a special rule to respect
> the immutable and append attribute on symlinks.
>
> [0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=152029
>
> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
> ---
>
> As discussed at LSF/MM -- I'd follow up on this low hanging fruit as
> the discussion had stalled on linux-xfs on review of the respective
> xfs_repair changes. This addresses the general API question, and
> as such I think could help establish order in how we split up patches
> for those changes.
>
> This requires some other eyeballs, and it also requires a putting it through
> xfstests which I can do in the next few days, hence the RFC. But better put it
> out for review already. I'd also like feedback from the linux-api folks to
> see if this matches their own known / documented expectations.
>
> fs/namei.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/fs/namei.c b/fs/namei.c
> index 186bd2464fd5..0f9069468cfb 100644
> --- a/fs/namei.c
> +++ b/fs/namei.c
> @@ -2719,6 +2719,14 @@ int __check_sticky(struct inode *dir, struct inode *inode)
> }
> EXPORT_SYMBOL(__check_sticky);
>
> +/* Process extra file attributes only when they make sense */
> +static bool may_delete_stx_attributes(struct inode *inode)
> +{
> + if (!S_ISLNK(inode->i_mode) && (IS_APPEND(inode) || IS_IMMUTABLE(inode)))
> + return false;
> + return true;
> +}
> +
> /*
> * Check whether we can remove a link victim from directory dir, check
> * whether the type of victim is right.
> @@ -2757,8 +2765,8 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
> if (IS_APPEND(dir))
> return -EPERM;
>
> - if (check_sticky(dir, inode) || IS_APPEND(inode) ||
> - IS_IMMUTABLE(inode) || IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode))
> + if (check_sticky(dir, inode) || !may_delete_stx_attributes(inode) ||
> + IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode))
> return -EPERM;
> if (isdir) {
> if (!d_is_dir(victim))
> --
> 2.17.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-xfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply
* [PATCH 14/14] rseq: selftests: Provide Makefile, scripts, gitignore (v2)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers, Shuah Khan
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
A run_param_test.sh script runs many variants of the parametrizable
tests.
Wire up the rseq Makefile, add directory entry into MAINTAINERS file.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-kselftest@vger.kernel.org
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Use only rseq, remove use of cpu_opv.
---
MAINTAINERS | 1 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/rseq/.gitignore | 6 ++
tools/testing/selftests/rseq/Makefile | 30 ++++++
tools/testing/selftests/rseq/run_param_test.sh | 121 +++++++++++++++++++++++++
5 files changed, 159 insertions(+)
create mode 100644 tools/testing/selftests/rseq/.gitignore
create mode 100644 tools/testing/selftests/rseq/Makefile
create mode 100755 tools/testing/selftests/rseq/run_param_test.sh
diff --git a/MAINTAINERS b/MAINTAINERS
index 4d61ce154dfc..5e8968b3ccae 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11991,6 +11991,7 @@ S: Supported
F: kernel/rseq.c
F: include/uapi/linux/rseq.h
F: include/trace/events/rseq.h
+F: tools/testing/selftests/rseq/
RFKILL
M: Johannes Berg <johannes@sipsolutions.net>
diff --git a/tools/testing/selftests/Makefile b/tools/testing/selftests/Makefile
index 32aafa92074c..593fb44c9cd4 100644
--- a/tools/testing/selftests/Makefile
+++ b/tools/testing/selftests/Makefile
@@ -28,6 +28,7 @@ TARGETS += powerpc
TARGETS += proc
TARGETS += pstore
TARGETS += ptrace
+TARGETS += rseq
TARGETS += seccomp
TARGETS += sigaltstack
TARGETS += size
diff --git a/tools/testing/selftests/rseq/.gitignore b/tools/testing/selftests/rseq/.gitignore
new file mode 100644
index 000000000000..cc610da7e369
--- /dev/null
+++ b/tools/testing/selftests/rseq/.gitignore
@@ -0,0 +1,6 @@
+basic_percpu_ops_test
+basic_test
+basic_rseq_op_test
+param_test
+param_test_benchmark
+param_test_compare_twice
diff --git a/tools/testing/selftests/rseq/Makefile b/tools/testing/selftests/rseq/Makefile
new file mode 100644
index 000000000000..c30c52e1d0d2
--- /dev/null
+++ b/tools/testing/selftests/rseq/Makefile
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: GPL-2.0+ OR MIT
+CFLAGS += -O2 -Wall -g -I./ -I../../../../usr/include/ -L./ -Wl,-rpath=./
+LDLIBS += -lpthread
+
+# Own dependencies because we only want to build against 1st prerequisite, but
+# still track changes to header files and depend on shared object.
+OVERRIDE_TARGETS = 1
+
+TEST_GEN_PROGS = basic_test basic_percpu_ops_test param_test \
+ param_test_benchmark param_test_compare_twice
+
+TEST_GEN_PROGS_EXTENDED = librseq.so
+
+TEST_PROGS = run_param_test.sh
+
+include ../lib.mk
+
+$(OUTPUT)/librseq.so: rseq.c rseq.h rseq-*.h
+ $(CC) $(CFLAGS) -shared -fPIC $< $(LDLIBS) -o $@
+
+$(OUTPUT)/%: %.c $(TEST_GEN_PROGS_EXTENDED) rseq.h rseq-*.h
+ $(CC) $(CFLAGS) $< $(LDLIBS) -lrseq -o $@
+
+$(OUTPUT)/param_test_benchmark: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
+ rseq.h rseq-*.h
+ $(CC) $(CFLAGS) -DBENCHMARK $< $(LDLIBS) -lrseq -o $@
+
+$(OUTPUT)/param_test_compare_twice: param_test.c $(TEST_GEN_PROGS_EXTENDED) \
+ rseq.h rseq-*.h
+ $(CC) $(CFLAGS) -DRSEQ_COMPARE_TWICE $< $(LDLIBS) -lrseq -o $@
diff --git a/tools/testing/selftests/rseq/run_param_test.sh b/tools/testing/selftests/rseq/run_param_test.sh
new file mode 100755
index 000000000000..3acd6d75ff9f
--- /dev/null
+++ b/tools/testing/selftests/rseq/run_param_test.sh
@@ -0,0 +1,121 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0+ or MIT
+
+EXTRA_ARGS=${@}
+
+OLDIFS="$IFS"
+IFS=$'\n'
+TEST_LIST=(
+ "-T s"
+ "-T l"
+ "-T b"
+ "-T b -M"
+ "-T m"
+ "-T m -M"
+ "-T i"
+)
+
+TEST_NAME=(
+ "spinlock"
+ "list"
+ "buffer"
+ "buffer with barrier"
+ "memcpy"
+ "memcpy with barrier"
+ "increment"
+)
+IFS="$OLDIFS"
+
+REPS=1000
+SLOW_REPS=100
+
+function do_tests()
+{
+ local i=0
+ while [ "$i" -lt "${#TEST_LIST[@]}" ]; do
+ echo "Running test ${TEST_NAME[$i]}"
+ ./param_test ${TEST_LIST[$i]} -r ${REPS} ${@} ${EXTRA_ARGS} || exit 1
+ echo "Running compare-twice test ${TEST_NAME[$i]}"
+ ./param_test_compare_twice ${TEST_LIST[$i]} -r ${REPS} ${@} ${EXTRA_ARGS} || exit 1
+ let "i++"
+ done
+}
+
+echo "Default parameters"
+do_tests
+
+echo "Loop injection: 10000 loops"
+
+OLDIFS="$IFS"
+IFS=$'\n'
+INJECT_LIST=(
+ "1"
+ "2"
+ "3"
+ "4"
+ "5"
+ "6"
+ "7"
+ "8"
+ "9"
+)
+IFS="$OLDIFS"
+
+NR_LOOPS=10000
+
+i=0
+while [ "$i" -lt "${#INJECT_LIST[@]}" ]; do
+ echo "Injecting at <${INJECT_LIST[$i]}>"
+ do_tests -${INJECT_LIST[i]} ${NR_LOOPS}
+ let "i++"
+done
+NR_LOOPS=
+
+function inject_blocking()
+{
+ OLDIFS="$IFS"
+ IFS=$'\n'
+ INJECT_LIST=(
+ "7"
+ "8"
+ "9"
+ )
+ IFS="$OLDIFS"
+
+ NR_LOOPS=-1
+
+ i=0
+ while [ "$i" -lt "${#INJECT_LIST[@]}" ]; do
+ echo "Injecting at <${INJECT_LIST[$i]}>"
+ do_tests -${INJECT_LIST[i]} -1 ${@}
+ let "i++"
+ done
+ NR_LOOPS=
+}
+
+echo "Yield injection (25%)"
+inject_blocking -m 4 -y
+
+echo "Yield injection (50%)"
+inject_blocking -m 2 -y
+
+echo "Yield injection (100%)"
+inject_blocking -m 1 -y
+
+echo "Kill injection (25%)"
+inject_blocking -m 4 -k
+
+echo "Kill injection (50%)"
+inject_blocking -m 2 -k
+
+echo "Kill injection (100%)"
+inject_blocking -m 1 -k
+
+echo "Sleep injection (1ms, 25%)"
+inject_blocking -m 4 -s 1
+
+echo "Sleep injection (1ms, 50%)"
+inject_blocking -m 2 -s 1
+
+echo "Sleep injection (1ms, 100%)"
+inject_blocking -m 1 -s 1
--
2.11.0
^ permalink raw reply related
* [PATCH 13/14] rseq: selftests: Provide parametrized tests (v2)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers, Shuah Khan
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
"param_test" is a parametrizable restartable sequences test. See
the "--help" output for usage.
"param_test_benchmark" is the same as "param_test", but it removes
testing book-keeping code to allow accurate benchmarks.
"param_test_compare_twice" is the same as "param_test", but it performs
each comparison within rseq critical section twice, thus validating
invariants. If any of the second comparisons fails, an error message
is printed and the test aborts.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-kselftest@vger.kernel.org
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Use only rseq, remove use of cpu_opv.
---
tools/testing/selftests/rseq/param_test.c | 1260 +++++++++++++++++++++++++++++
1 file changed, 1260 insertions(+)
create mode 100644 tools/testing/selftests/rseq/param_test.c
diff --git a/tools/testing/selftests/rseq/param_test.c b/tools/testing/selftests/rseq/param_test.c
new file mode 100644
index 000000000000..6a9f602a8718
--- /dev/null
+++ b/tools/testing/selftests/rseq/param_test.c
@@ -0,0 +1,1260 @@
+// SPDX-License-Identifier: LGPL-2.1
+#define _GNU_SOURCE
+#include <assert.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syscall.h>
+#include <unistd.h>
+#include <poll.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <errno.h>
+#include <stddef.h>
+
+static inline pid_t gettid(void)
+{
+ return syscall(__NR_gettid);
+}
+
+#define NR_INJECT 9
+static int loop_cnt[NR_INJECT + 1];
+
+static int loop_cnt_1 asm("asm_loop_cnt_1") __attribute__((used));
+static int loop_cnt_2 asm("asm_loop_cnt_2") __attribute__((used));
+static int loop_cnt_3 asm("asm_loop_cnt_3") __attribute__((used));
+static int loop_cnt_4 asm("asm_loop_cnt_4") __attribute__((used));
+static int loop_cnt_5 asm("asm_loop_cnt_5") __attribute__((used));
+static int loop_cnt_6 asm("asm_loop_cnt_6") __attribute__((used));
+
+static int opt_modulo, verbose;
+
+static int opt_yield, opt_signal, opt_sleep,
+ opt_disable_rseq, opt_threads = 200,
+ opt_disable_mod = 0, opt_test = 's', opt_mb = 0;
+
+#ifndef RSEQ_SKIP_FASTPATH
+static long long opt_reps = 5000;
+#else
+static long long opt_reps = 100;
+#endif
+
+static __thread __attribute__((tls_model("initial-exec")))
+unsigned int signals_delivered;
+
+#ifndef BENCHMARK
+
+static __thread __attribute__((tls_model("initial-exec"), unused))
+unsigned int yield_mod_cnt, nr_abort;
+
+#define printf_verbose(fmt, ...) \
+ do { \
+ if (verbose) \
+ printf(fmt, ## __VA_ARGS__); \
+ } while (0)
+
+#if defined(__x86_64__) || defined(__i386__)
+
+#define INJECT_ASM_REG "eax"
+
+#define RSEQ_INJECT_CLOBBER \
+ , INJECT_ASM_REG
+
+#ifdef __i386__
+
+#define RSEQ_INJECT_ASM(n) \
+ "mov asm_loop_cnt_" #n ", %%" INJECT_ASM_REG "\n\t" \
+ "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \
+ "jz 333f\n\t" \
+ "222:\n\t" \
+ "dec %%" INJECT_ASM_REG "\n\t" \
+ "jnz 222b\n\t" \
+ "333:\n\t"
+
+#elif defined(__x86_64__)
+
+#define RSEQ_INJECT_ASM(n) \
+ "lea asm_loop_cnt_" #n "(%%rip), %%" INJECT_ASM_REG "\n\t" \
+ "mov (%%" INJECT_ASM_REG "), %%" INJECT_ASM_REG "\n\t" \
+ "test %%" INJECT_ASM_REG ",%%" INJECT_ASM_REG "\n\t" \
+ "jz 333f\n\t" \
+ "222:\n\t" \
+ "dec %%" INJECT_ASM_REG "\n\t" \
+ "jnz 222b\n\t" \
+ "333:\n\t"
+
+#else
+#error "Unsupported architecture"
+#endif
+
+#elif defined(__ARMEL__)
+
+#define RSEQ_INJECT_INPUT \
+ , [loop_cnt_1]"m"(loop_cnt[1]) \
+ , [loop_cnt_2]"m"(loop_cnt[2]) \
+ , [loop_cnt_3]"m"(loop_cnt[3]) \
+ , [loop_cnt_4]"m"(loop_cnt[4]) \
+ , [loop_cnt_5]"m"(loop_cnt[5]) \
+ , [loop_cnt_6]"m"(loop_cnt[6])
+
+#define INJECT_ASM_REG "r4"
+
+#define RSEQ_INJECT_CLOBBER \
+ , INJECT_ASM_REG
+
+#define RSEQ_INJECT_ASM(n) \
+ "ldr " INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
+ "cmp " INJECT_ASM_REG ", #0\n\t" \
+ "beq 333f\n\t" \
+ "222:\n\t" \
+ "subs " INJECT_ASM_REG ", #1\n\t" \
+ "bne 222b\n\t" \
+ "333:\n\t"
+
+#elif __PPC__
+
+#define RSEQ_INJECT_INPUT \
+ , [loop_cnt_1]"m"(loop_cnt[1]) \
+ , [loop_cnt_2]"m"(loop_cnt[2]) \
+ , [loop_cnt_3]"m"(loop_cnt[3]) \
+ , [loop_cnt_4]"m"(loop_cnt[4]) \
+ , [loop_cnt_5]"m"(loop_cnt[5]) \
+ , [loop_cnt_6]"m"(loop_cnt[6])
+
+#define INJECT_ASM_REG "r18"
+
+#define RSEQ_INJECT_CLOBBER \
+ , INJECT_ASM_REG
+
+#define RSEQ_INJECT_ASM(n) \
+ "lwz %%" INJECT_ASM_REG ", %[loop_cnt_" #n "]\n\t" \
+ "cmpwi %%" INJECT_ASM_REG ", 0\n\t" \
+ "beq 333f\n\t" \
+ "222:\n\t" \
+ "subic. %%" INJECT_ASM_REG ", %%" INJECT_ASM_REG ", 1\n\t" \
+ "bne 222b\n\t" \
+ "333:\n\t"
+#else
+#error unsupported target
+#endif
+
+#define RSEQ_INJECT_FAILED \
+ nr_abort++;
+
+#define RSEQ_INJECT_C(n) \
+{ \
+ int loc_i, loc_nr_loops = loop_cnt[n]; \
+ \
+ for (loc_i = 0; loc_i < loc_nr_loops; loc_i++) { \
+ rseq_barrier(); \
+ } \
+ if (loc_nr_loops == -1 && opt_modulo) { \
+ if (yield_mod_cnt == opt_modulo - 1) { \
+ if (opt_sleep > 0) \
+ poll(NULL, 0, opt_sleep); \
+ if (opt_yield) \
+ sched_yield(); \
+ if (opt_signal) \
+ raise(SIGUSR1); \
+ yield_mod_cnt = 0; \
+ } else { \
+ yield_mod_cnt++; \
+ } \
+ } \
+}
+
+#else
+
+#define printf_verbose(fmt, ...)
+
+#endif /* BENCHMARK */
+
+#include "rseq.h"
+
+struct percpu_lock_entry {
+ intptr_t v;
+} __attribute__((aligned(128)));
+
+struct percpu_lock {
+ struct percpu_lock_entry c[CPU_SETSIZE];
+};
+
+struct test_data_entry {
+ intptr_t count;
+} __attribute__((aligned(128)));
+
+struct spinlock_test_data {
+ struct percpu_lock lock;
+ struct test_data_entry c[CPU_SETSIZE];
+};
+
+struct spinlock_thread_test_data {
+ struct spinlock_test_data *data;
+ long long reps;
+ int reg;
+};
+
+struct inc_test_data {
+ struct test_data_entry c[CPU_SETSIZE];
+};
+
+struct inc_thread_test_data {
+ struct inc_test_data *data;
+ long long reps;
+ int reg;
+};
+
+struct percpu_list_node {
+ intptr_t data;
+ struct percpu_list_node *next;
+};
+
+struct percpu_list_entry {
+ struct percpu_list_node *head;
+} __attribute__((aligned(128)));
+
+struct percpu_list {
+ struct percpu_list_entry c[CPU_SETSIZE];
+};
+
+#define BUFFER_ITEM_PER_CPU 100
+
+struct percpu_buffer_node {
+ intptr_t data;
+};
+
+struct percpu_buffer_entry {
+ intptr_t offset;
+ intptr_t buflen;
+ struct percpu_buffer_node **array;
+} __attribute__((aligned(128)));
+
+struct percpu_buffer {
+ struct percpu_buffer_entry c[CPU_SETSIZE];
+};
+
+#define MEMCPY_BUFFER_ITEM_PER_CPU 100
+
+struct percpu_memcpy_buffer_node {
+ intptr_t data1;
+ uint64_t data2;
+};
+
+struct percpu_memcpy_buffer_entry {
+ intptr_t offset;
+ intptr_t buflen;
+ struct percpu_memcpy_buffer_node *array;
+} __attribute__((aligned(128)));
+
+struct percpu_memcpy_buffer {
+ struct percpu_memcpy_buffer_entry c[CPU_SETSIZE];
+};
+
+/* A simple percpu spinlock. Grabs lock on current cpu. */
+static int rseq_this_cpu_lock(struct percpu_lock *lock)
+{
+ int cpu;
+
+ for (;;) {
+ int ret;
+
+ cpu = rseq_cpu_start();
+ ret = rseq_cmpeqv_storev(&lock->c[cpu].v,
+ 0, 1, cpu);
+ if (rseq_likely(!ret))
+ break;
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ /*
+ * Acquire semantic when taking lock after control dependency.
+ * Matches rseq_smp_store_release().
+ */
+ rseq_smp_acquire__after_ctrl_dep();
+ return cpu;
+}
+
+static void rseq_percpu_unlock(struct percpu_lock *lock, int cpu)
+{
+ assert(lock->c[cpu].v == 1);
+ /*
+ * Release lock, with release semantic. Matches
+ * rseq_smp_acquire__after_ctrl_dep().
+ */
+ rseq_smp_store_release(&lock->c[cpu].v, 0);
+}
+
+void *test_percpu_spinlock_thread(void *arg)
+{
+ struct spinlock_thread_test_data *thread_data = arg;
+ struct spinlock_test_data *data = thread_data->data;
+ long long i, reps;
+
+ if (!opt_disable_rseq && thread_data->reg &&
+ rseq_register_current_thread())
+ abort();
+ reps = thread_data->reps;
+ for (i = 0; i < reps; i++) {
+ int cpu = rseq_cpu_start();
+
+ cpu = rseq_this_cpu_lock(&data->lock);
+ data->c[cpu].count++;
+ rseq_percpu_unlock(&data->lock, cpu);
+#ifndef BENCHMARK
+ if (i != 0 && !(i % (reps / 10)))
+ printf_verbose("tid %d: count %lld\n", (int) gettid(), i);
+#endif
+ }
+ printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
+ (int) gettid(), nr_abort, signals_delivered);
+ if (!opt_disable_rseq && thread_data->reg &&
+ rseq_unregister_current_thread())
+ abort();
+ return NULL;
+}
+
+/*
+ * A simple test which implements a sharded counter using a per-cpu
+ * lock. Obviously real applications might prefer to simply use a
+ * per-cpu increment; however, this is reasonable for a test and the
+ * lock can be extended to synchronize more complicated operations.
+ */
+void test_percpu_spinlock(void)
+{
+ const int num_threads = opt_threads;
+ int i, ret;
+ uint64_t sum;
+ pthread_t test_threads[num_threads];
+ struct spinlock_test_data data;
+ struct spinlock_thread_test_data thread_data[num_threads];
+
+ memset(&data, 0, sizeof(data));
+ for (i = 0; i < num_threads; i++) {
+ thread_data[i].reps = opt_reps;
+ if (opt_disable_mod <= 0 || (i % opt_disable_mod))
+ thread_data[i].reg = 1;
+ else
+ thread_data[i].reg = 0;
+ thread_data[i].data = &data;
+ ret = pthread_create(&test_threads[i], NULL,
+ test_percpu_spinlock_thread,
+ &thread_data[i]);
+ if (ret) {
+ errno = ret;
+ perror("pthread_create");
+ abort();
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_join(test_threads[i], NULL);
+ if (ret) {
+ errno = ret;
+ perror("pthread_join");
+ abort();
+ }
+ }
+
+ sum = 0;
+ for (i = 0; i < CPU_SETSIZE; i++)
+ sum += data.c[i].count;
+
+ assert(sum == (uint64_t)opt_reps * num_threads);
+}
+
+void *test_percpu_inc_thread(void *arg)
+{
+ struct inc_thread_test_data *thread_data = arg;
+ struct inc_test_data *data = thread_data->data;
+ long long i, reps;
+
+ if (!opt_disable_rseq && thread_data->reg &&
+ rseq_register_current_thread())
+ abort();
+ reps = thread_data->reps;
+ for (i = 0; i < reps; i++) {
+ int ret;
+
+ do {
+ int cpu;
+
+ cpu = rseq_cpu_start();
+ ret = rseq_addv(&data->c[cpu].count, 1, cpu);
+ } while (rseq_unlikely(ret));
+#ifndef BENCHMARK
+ if (i != 0 && !(i % (reps / 10)))
+ printf_verbose("tid %d: count %lld\n", (int) gettid(), i);
+#endif
+ }
+ printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
+ (int) gettid(), nr_abort, signals_delivered);
+ if (!opt_disable_rseq && thread_data->reg &&
+ rseq_unregister_current_thread())
+ abort();
+ return NULL;
+}
+
+void test_percpu_inc(void)
+{
+ const int num_threads = opt_threads;
+ int i, ret;
+ uint64_t sum;
+ pthread_t test_threads[num_threads];
+ struct inc_test_data data;
+ struct inc_thread_test_data thread_data[num_threads];
+
+ memset(&data, 0, sizeof(data));
+ for (i = 0; i < num_threads; i++) {
+ thread_data[i].reps = opt_reps;
+ if (opt_disable_mod <= 0 || (i % opt_disable_mod))
+ thread_data[i].reg = 1;
+ else
+ thread_data[i].reg = 0;
+ thread_data[i].data = &data;
+ ret = pthread_create(&test_threads[i], NULL,
+ test_percpu_inc_thread,
+ &thread_data[i]);
+ if (ret) {
+ errno = ret;
+ perror("pthread_create");
+ abort();
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_join(test_threads[i], NULL);
+ if (ret) {
+ errno = ret;
+ perror("pthread_join");
+ abort();
+ }
+ }
+
+ sum = 0;
+ for (i = 0; i < CPU_SETSIZE; i++)
+ sum += data.c[i].count;
+
+ assert(sum == (uint64_t)opt_reps * num_threads);
+}
+
+void this_cpu_list_push(struct percpu_list *list,
+ struct percpu_list_node *node,
+ int *_cpu)
+{
+ int cpu;
+
+ for (;;) {
+ intptr_t *targetptr, newval, expect;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ /* Load list->c[cpu].head with single-copy atomicity. */
+ expect = (intptr_t)RSEQ_READ_ONCE(list->c[cpu].head);
+ newval = (intptr_t)node;
+ targetptr = (intptr_t *)&list->c[cpu].head;
+ node->next = (struct percpu_list_node *)expect;
+ ret = rseq_cmpeqv_storev(targetptr, expect, newval, cpu);
+ if (rseq_likely(!ret))
+ break;
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+}
+
+/*
+ * Unlike a traditional lock-less linked list; the availability of a
+ * rseq primitive allows us to implement pop without concerns over
+ * ABA-type races.
+ */
+struct percpu_list_node *this_cpu_list_pop(struct percpu_list *list,
+ int *_cpu)
+{
+ struct percpu_list_node *node = NULL;
+ int cpu;
+
+ for (;;) {
+ struct percpu_list_node *head;
+ intptr_t *targetptr, expectnot, *load;
+ off_t offset;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ targetptr = (intptr_t *)&list->c[cpu].head;
+ expectnot = (intptr_t)NULL;
+ offset = offsetof(struct percpu_list_node, next);
+ load = (intptr_t *)&head;
+ ret = rseq_cmpnev_storeoffp_load(targetptr, expectnot,
+ offset, load, cpu);
+ if (rseq_likely(!ret)) {
+ node = head;
+ break;
+ }
+ if (ret > 0)
+ break;
+ /* Retry if rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+ return node;
+}
+
+/*
+ * __percpu_list_pop is not safe against concurrent accesses. Should
+ * only be used on lists that are not concurrently modified.
+ */
+struct percpu_list_node *__percpu_list_pop(struct percpu_list *list, int cpu)
+{
+ struct percpu_list_node *node;
+
+ node = list->c[cpu].head;
+ if (!node)
+ return NULL;
+ list->c[cpu].head = node->next;
+ return node;
+}
+
+void *test_percpu_list_thread(void *arg)
+{
+ long long i, reps;
+ struct percpu_list *list = (struct percpu_list *)arg;
+
+ if (!opt_disable_rseq && rseq_register_current_thread())
+ abort();
+
+ reps = opt_reps;
+ for (i = 0; i < reps; i++) {
+ struct percpu_list_node *node;
+
+ node = this_cpu_list_pop(list, NULL);
+ if (opt_yield)
+ sched_yield(); /* encourage shuffling */
+ if (node)
+ this_cpu_list_push(list, node, NULL);
+ }
+
+ printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
+ (int) gettid(), nr_abort, signals_delivered);
+ if (!opt_disable_rseq && rseq_unregister_current_thread())
+ abort();
+
+ return NULL;
+}
+
+/* Simultaneous modification to a per-cpu linked list from many threads. */
+void test_percpu_list(void)
+{
+ const int num_threads = opt_threads;
+ int i, j, ret;
+ uint64_t sum = 0, expected_sum = 0;
+ struct percpu_list list;
+ pthread_t test_threads[num_threads];
+ cpu_set_t allowed_cpus;
+
+ memset(&list, 0, sizeof(list));
+
+ /* Generate list entries for every usable cpu. */
+ sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+ for (j = 1; j <= 100; j++) {
+ struct percpu_list_node *node;
+
+ expected_sum += j;
+
+ node = malloc(sizeof(*node));
+ assert(node);
+ node->data = j;
+ node->next = list.c[i].head;
+ list.c[i].head = node;
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_create(&test_threads[i], NULL,
+ test_percpu_list_thread, &list);
+ if (ret) {
+ errno = ret;
+ perror("pthread_create");
+ abort();
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_join(test_threads[i], NULL);
+ if (ret) {
+ errno = ret;
+ perror("pthread_join");
+ abort();
+ }
+ }
+
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ struct percpu_list_node *node;
+
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+
+ while ((node = __percpu_list_pop(&list, i))) {
+ sum += node->data;
+ free(node);
+ }
+ }
+
+ /*
+ * All entries should now be accounted for (unless some external
+ * actor is interfering with our allowed affinity while this
+ * test is running).
+ */
+ assert(sum == expected_sum);
+}
+
+bool this_cpu_buffer_push(struct percpu_buffer *buffer,
+ struct percpu_buffer_node *node,
+ int *_cpu)
+{
+ bool result = false;
+ int cpu;
+
+ for (;;) {
+ intptr_t *targetptr_spec, newval_spec;
+ intptr_t *targetptr_final, newval_final;
+ intptr_t offset;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
+ if (offset == buffer->c[cpu].buflen)
+ break;
+ newval_spec = (intptr_t)node;
+ targetptr_spec = (intptr_t *)&buffer->c[cpu].array[offset];
+ newval_final = offset + 1;
+ targetptr_final = &buffer->c[cpu].offset;
+ if (opt_mb)
+ ret = rseq_cmpeqv_trystorev_storev_release(
+ targetptr_final, offset, targetptr_spec,
+ newval_spec, newval_final, cpu);
+ else
+ ret = rseq_cmpeqv_trystorev_storev(targetptr_final,
+ offset, targetptr_spec, newval_spec,
+ newval_final, cpu);
+ if (rseq_likely(!ret)) {
+ result = true;
+ break;
+ }
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+ return result;
+}
+
+struct percpu_buffer_node *this_cpu_buffer_pop(struct percpu_buffer *buffer,
+ int *_cpu)
+{
+ struct percpu_buffer_node *head;
+ int cpu;
+
+ for (;;) {
+ intptr_t *targetptr, newval;
+ intptr_t offset;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ /* Load offset with single-copy atomicity. */
+ offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
+ if (offset == 0) {
+ head = NULL;
+ break;
+ }
+ head = RSEQ_READ_ONCE(buffer->c[cpu].array[offset - 1]);
+ newval = offset - 1;
+ targetptr = (intptr_t *)&buffer->c[cpu].offset;
+ ret = rseq_cmpeqv_cmpeqv_storev(targetptr, offset,
+ (intptr_t *)&buffer->c[cpu].array[offset - 1],
+ (intptr_t)head, newval, cpu);
+ if (rseq_likely(!ret))
+ break;
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+ return head;
+}
+
+/*
+ * __percpu_buffer_pop is not safe against concurrent accesses. Should
+ * only be used on buffers that are not concurrently modified.
+ */
+struct percpu_buffer_node *__percpu_buffer_pop(struct percpu_buffer *buffer,
+ int cpu)
+{
+ struct percpu_buffer_node *head;
+ intptr_t offset;
+
+ offset = buffer->c[cpu].offset;
+ if (offset == 0)
+ return NULL;
+ head = buffer->c[cpu].array[offset - 1];
+ buffer->c[cpu].offset = offset - 1;
+ return head;
+}
+
+void *test_percpu_buffer_thread(void *arg)
+{
+ long long i, reps;
+ struct percpu_buffer *buffer = (struct percpu_buffer *)arg;
+
+ if (!opt_disable_rseq && rseq_register_current_thread())
+ abort();
+
+ reps = opt_reps;
+ for (i = 0; i < reps; i++) {
+ struct percpu_buffer_node *node;
+
+ node = this_cpu_buffer_pop(buffer, NULL);
+ if (opt_yield)
+ sched_yield(); /* encourage shuffling */
+ if (node) {
+ if (!this_cpu_buffer_push(buffer, node, NULL)) {
+ /* Should increase buffer size. */
+ abort();
+ }
+ }
+ }
+
+ printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
+ (int) gettid(), nr_abort, signals_delivered);
+ if (!opt_disable_rseq && rseq_unregister_current_thread())
+ abort();
+
+ return NULL;
+}
+
+/* Simultaneous modification to a per-cpu buffer from many threads. */
+void test_percpu_buffer(void)
+{
+ const int num_threads = opt_threads;
+ int i, j, ret;
+ uint64_t sum = 0, expected_sum = 0;
+ struct percpu_buffer buffer;
+ pthread_t test_threads[num_threads];
+ cpu_set_t allowed_cpus;
+
+ memset(&buffer, 0, sizeof(buffer));
+
+ /* Generate list entries for every usable cpu. */
+ sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+ /* Worse-case is every item in same CPU. */
+ buffer.c[i].array =
+ malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE *
+ BUFFER_ITEM_PER_CPU);
+ assert(buffer.c[i].array);
+ buffer.c[i].buflen = CPU_SETSIZE * BUFFER_ITEM_PER_CPU;
+ for (j = 1; j <= BUFFER_ITEM_PER_CPU; j++) {
+ struct percpu_buffer_node *node;
+
+ expected_sum += j;
+
+ /*
+ * We could theoretically put the word-sized
+ * "data" directly in the buffer. However, we
+ * want to model objects that would not fit
+ * within a single word, so allocate an object
+ * for each node.
+ */
+ node = malloc(sizeof(*node));
+ assert(node);
+ node->data = j;
+ buffer.c[i].array[j - 1] = node;
+ buffer.c[i].offset++;
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_create(&test_threads[i], NULL,
+ test_percpu_buffer_thread, &buffer);
+ if (ret) {
+ errno = ret;
+ perror("pthread_create");
+ abort();
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_join(test_threads[i], NULL);
+ if (ret) {
+ errno = ret;
+ perror("pthread_join");
+ abort();
+ }
+ }
+
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ struct percpu_buffer_node *node;
+
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+
+ while ((node = __percpu_buffer_pop(&buffer, i))) {
+ sum += node->data;
+ free(node);
+ }
+ free(buffer.c[i].array);
+ }
+
+ /*
+ * All entries should now be accounted for (unless some external
+ * actor is interfering with our allowed affinity while this
+ * test is running).
+ */
+ assert(sum == expected_sum);
+}
+
+bool this_cpu_memcpy_buffer_push(struct percpu_memcpy_buffer *buffer,
+ struct percpu_memcpy_buffer_node item,
+ int *_cpu)
+{
+ bool result = false;
+ int cpu;
+
+ for (;;) {
+ intptr_t *targetptr_final, newval_final, offset;
+ char *destptr, *srcptr;
+ size_t copylen;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ /* Load offset with single-copy atomicity. */
+ offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
+ if (offset == buffer->c[cpu].buflen)
+ break;
+ destptr = (char *)&buffer->c[cpu].array[offset];
+ srcptr = (char *)&item;
+ /* copylen must be <= 4kB. */
+ copylen = sizeof(item);
+ newval_final = offset + 1;
+ targetptr_final = &buffer->c[cpu].offset;
+ if (opt_mb)
+ ret = rseq_cmpeqv_trymemcpy_storev_release(
+ targetptr_final, offset,
+ destptr, srcptr, copylen,
+ newval_final, cpu);
+ else
+ ret = rseq_cmpeqv_trymemcpy_storev(targetptr_final,
+ offset, destptr, srcptr, copylen,
+ newval_final, cpu);
+ if (rseq_likely(!ret)) {
+ result = true;
+ break;
+ }
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+ return result;
+}
+
+bool this_cpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer,
+ struct percpu_memcpy_buffer_node *item,
+ int *_cpu)
+{
+ bool result = false;
+ int cpu;
+
+ for (;;) {
+ intptr_t *targetptr_final, newval_final, offset;
+ char *destptr, *srcptr;
+ size_t copylen;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ /* Load offset with single-copy atomicity. */
+ offset = RSEQ_READ_ONCE(buffer->c[cpu].offset);
+ if (offset == 0)
+ break;
+ destptr = (char *)item;
+ srcptr = (char *)&buffer->c[cpu].array[offset - 1];
+ /* copylen must be <= 4kB. */
+ copylen = sizeof(*item);
+ newval_final = offset - 1;
+ targetptr_final = &buffer->c[cpu].offset;
+ ret = rseq_cmpeqv_trymemcpy_storev(targetptr_final,
+ offset, destptr, srcptr, copylen,
+ newval_final, cpu);
+ if (rseq_likely(!ret)) {
+ result = true;
+ break;
+ }
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+ return result;
+}
+
+/*
+ * __percpu_memcpy_buffer_pop is not safe against concurrent accesses. Should
+ * only be used on buffers that are not concurrently modified.
+ */
+bool __percpu_memcpy_buffer_pop(struct percpu_memcpy_buffer *buffer,
+ struct percpu_memcpy_buffer_node *item,
+ int cpu)
+{
+ intptr_t offset;
+
+ offset = buffer->c[cpu].offset;
+ if (offset == 0)
+ return false;
+ memcpy(item, &buffer->c[cpu].array[offset - 1], sizeof(*item));
+ buffer->c[cpu].offset = offset - 1;
+ return true;
+}
+
+void *test_percpu_memcpy_buffer_thread(void *arg)
+{
+ long long i, reps;
+ struct percpu_memcpy_buffer *buffer = (struct percpu_memcpy_buffer *)arg;
+
+ if (!opt_disable_rseq && rseq_register_current_thread())
+ abort();
+
+ reps = opt_reps;
+ for (i = 0; i < reps; i++) {
+ struct percpu_memcpy_buffer_node item;
+ bool result;
+
+ result = this_cpu_memcpy_buffer_pop(buffer, &item, NULL);
+ if (opt_yield)
+ sched_yield(); /* encourage shuffling */
+ if (result) {
+ if (!this_cpu_memcpy_buffer_push(buffer, item, NULL)) {
+ /* Should increase buffer size. */
+ abort();
+ }
+ }
+ }
+
+ printf_verbose("tid %d: number of rseq abort: %d, signals delivered: %u\n",
+ (int) gettid(), nr_abort, signals_delivered);
+ if (!opt_disable_rseq && rseq_unregister_current_thread())
+ abort();
+
+ return NULL;
+}
+
+/* Simultaneous modification to a per-cpu buffer from many threads. */
+void test_percpu_memcpy_buffer(void)
+{
+ const int num_threads = opt_threads;
+ int i, j, ret;
+ uint64_t sum = 0, expected_sum = 0;
+ struct percpu_memcpy_buffer buffer;
+ pthread_t test_threads[num_threads];
+ cpu_set_t allowed_cpus;
+
+ memset(&buffer, 0, sizeof(buffer));
+
+ /* Generate list entries for every usable cpu. */
+ sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+ /* Worse-case is every item in same CPU. */
+ buffer.c[i].array =
+ malloc(sizeof(*buffer.c[i].array) * CPU_SETSIZE *
+ MEMCPY_BUFFER_ITEM_PER_CPU);
+ assert(buffer.c[i].array);
+ buffer.c[i].buflen = CPU_SETSIZE * MEMCPY_BUFFER_ITEM_PER_CPU;
+ for (j = 1; j <= MEMCPY_BUFFER_ITEM_PER_CPU; j++) {
+ expected_sum += 2 * j + 1;
+
+ /*
+ * We could theoretically put the word-sized
+ * "data" directly in the buffer. However, we
+ * want to model objects that would not fit
+ * within a single word, so allocate an object
+ * for each node.
+ */
+ buffer.c[i].array[j - 1].data1 = j;
+ buffer.c[i].array[j - 1].data2 = j + 1;
+ buffer.c[i].offset++;
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_create(&test_threads[i], NULL,
+ test_percpu_memcpy_buffer_thread,
+ &buffer);
+ if (ret) {
+ errno = ret;
+ perror("pthread_create");
+ abort();
+ }
+ }
+
+ for (i = 0; i < num_threads; i++) {
+ ret = pthread_join(test_threads[i], NULL);
+ if (ret) {
+ errno = ret;
+ perror("pthread_join");
+ abort();
+ }
+ }
+
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ struct percpu_memcpy_buffer_node item;
+
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+
+ while (__percpu_memcpy_buffer_pop(&buffer, &item, i)) {
+ sum += item.data1;
+ sum += item.data2;
+ }
+ free(buffer.c[i].array);
+ }
+
+ /*
+ * All entries should now be accounted for (unless some external
+ * actor is interfering with our allowed affinity while this
+ * test is running).
+ */
+ assert(sum == expected_sum);
+}
+
+static void test_signal_interrupt_handler(int signo)
+{
+ signals_delivered++;
+}
+
+static int set_signal_handler(void)
+{
+ int ret = 0;
+ struct sigaction sa;
+ sigset_t sigset;
+
+ ret = sigemptyset(&sigset);
+ if (ret < 0) {
+ perror("sigemptyset");
+ return ret;
+ }
+
+ sa.sa_handler = test_signal_interrupt_handler;
+ sa.sa_mask = sigset;
+ sa.sa_flags = 0;
+ ret = sigaction(SIGUSR1, &sa, NULL);
+ if (ret < 0) {
+ perror("sigaction");
+ return ret;
+ }
+
+ printf_verbose("Signal handler set for SIGUSR1\n");
+
+ return ret;
+}
+
+static void show_usage(int argc, char **argv)
+{
+ printf("Usage : %s <OPTIONS>\n",
+ argv[0]);
+ printf("OPTIONS:\n");
+ printf(" [-1 loops] Number of loops for delay injection 1\n");
+ printf(" [-2 loops] Number of loops for delay injection 2\n");
+ printf(" [-3 loops] Number of loops for delay injection 3\n");
+ printf(" [-4 loops] Number of loops for delay injection 4\n");
+ printf(" [-5 loops] Number of loops for delay injection 5\n");
+ printf(" [-6 loops] Number of loops for delay injection 6\n");
+ printf(" [-7 loops] Number of loops for delay injection 7 (-1 to enable -m)\n");
+ printf(" [-8 loops] Number of loops for delay injection 8 (-1 to enable -m)\n");
+ printf(" [-9 loops] Number of loops for delay injection 9 (-1 to enable -m)\n");
+ printf(" [-m N] Yield/sleep/kill every modulo N (default 0: disabled) (>= 0)\n");
+ printf(" [-y] Yield\n");
+ printf(" [-k] Kill thread with signal\n");
+ printf(" [-s S] S: =0: disabled (default), >0: sleep time (ms)\n");
+ printf(" [-t N] Number of threads (default 200)\n");
+ printf(" [-r N] Number of repetitions per thread (default 5000)\n");
+ printf(" [-d] Disable rseq system call (no initialization)\n");
+ printf(" [-D M] Disable rseq for each M threads\n");
+ printf(" [-T test] Choose test: (s)pinlock, (l)ist, (b)uffer, (m)emcpy, (i)ncrement\n");
+ printf(" [-M] Push into buffer and memcpy buffer with memory barriers.\n");
+ printf(" [-v] Verbose output.\n");
+ printf(" [-h] Show this help.\n");
+ printf("\n");
+}
+
+int main(int argc, char **argv)
+{
+ int i;
+
+ for (i = 1; i < argc; i++) {
+ if (argv[i][0] != '-')
+ continue;
+ switch (argv[i][1]) {
+ case '1':
+ case '2':
+ case '3':
+ case '4':
+ case '5':
+ case '6':
+ case '7':
+ case '8':
+ case '9':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ loop_cnt[argv[i][1] - '0'] = atol(argv[i + 1]);
+ i++;
+ break;
+ case 'm':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ opt_modulo = atol(argv[i + 1]);
+ if (opt_modulo < 0) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ i++;
+ break;
+ case 's':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ opt_sleep = atol(argv[i + 1]);
+ if (opt_sleep < 0) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ i++;
+ break;
+ case 'y':
+ opt_yield = 1;
+ break;
+ case 'k':
+ opt_signal = 1;
+ break;
+ case 'd':
+ opt_disable_rseq = 1;
+ break;
+ case 'D':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ opt_disable_mod = atol(argv[i + 1]);
+ if (opt_disable_mod < 0) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ i++;
+ break;
+ case 't':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ opt_threads = atol(argv[i + 1]);
+ if (opt_threads < 0) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ i++;
+ break;
+ case 'r':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ opt_reps = atoll(argv[i + 1]);
+ if (opt_reps < 0) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ i++;
+ break;
+ case 'h':
+ show_usage(argc, argv);
+ goto end;
+ case 'T':
+ if (argc < i + 2) {
+ show_usage(argc, argv);
+ goto error;
+ }
+ opt_test = *argv[i + 1];
+ switch (opt_test) {
+ case 's':
+ case 'l':
+ case 'i':
+ case 'b':
+ case 'm':
+ break;
+ default:
+ show_usage(argc, argv);
+ goto error;
+ }
+ i++;
+ break;
+ case 'v':
+ verbose = 1;
+ break;
+ case 'M':
+ opt_mb = 1;
+ break;
+ default:
+ show_usage(argc, argv);
+ goto error;
+ }
+ }
+
+ loop_cnt_1 = loop_cnt[1];
+ loop_cnt_2 = loop_cnt[2];
+ loop_cnt_3 = loop_cnt[3];
+ loop_cnt_4 = loop_cnt[4];
+ loop_cnt_5 = loop_cnt[5];
+ loop_cnt_6 = loop_cnt[6];
+
+ if (set_signal_handler())
+ goto error;
+
+ if (!opt_disable_rseq && rseq_register_current_thread())
+ goto error;
+ switch (opt_test) {
+ case 's':
+ printf_verbose("spinlock\n");
+ test_percpu_spinlock();
+ break;
+ case 'l':
+ printf_verbose("linked list\n");
+ test_percpu_list();
+ break;
+ case 'b':
+ printf_verbose("buffer\n");
+ test_percpu_buffer();
+ break;
+ case 'm':
+ printf_verbose("memcpy buffer\n");
+ test_percpu_memcpy_buffer();
+ break;
+ case 'i':
+ printf_verbose("counter increment\n");
+ test_percpu_inc();
+ break;
+ }
+ if (!opt_disable_rseq && rseq_unregister_current_thread())
+ abort();
+end:
+ return 0;
+
+error:
+ return -1;
+}
--
2.11.0
^ permalink raw reply related
* [PATCH 12/14] rseq: selftests: Provide basic percpu ops test (v2)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers, Shuah Khan
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
"basic_percpu_ops_test" is a slightly more "realistic" variant,
implementing a few simple per-cpu operations and testing their
correctness.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-kselftest@vger.kernel.org
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Use only rseq, remove use of cpu_opv system call.
---
.../testing/selftests/rseq/basic_percpu_ops_test.c | 313 +++++++++++++++++++++
1 file changed, 313 insertions(+)
create mode 100644 tools/testing/selftests/rseq/basic_percpu_ops_test.c
diff --git a/tools/testing/selftests/rseq/basic_percpu_ops_test.c b/tools/testing/selftests/rseq/basic_percpu_ops_test.c
new file mode 100644
index 000000000000..96ef27905879
--- /dev/null
+++ b/tools/testing/selftests/rseq/basic_percpu_ops_test.c
@@ -0,0 +1,313 @@
+// SPDX-License-Identifier: LGPL-2.1
+#define _GNU_SOURCE
+#include <assert.h>
+#include <pthread.h>
+#include <sched.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stddef.h>
+
+#include "rseq.h"
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+struct percpu_lock_entry {
+ intptr_t v;
+} __attribute__((aligned(128)));
+
+struct percpu_lock {
+ struct percpu_lock_entry c[CPU_SETSIZE];
+};
+
+struct test_data_entry {
+ intptr_t count;
+} __attribute__((aligned(128)));
+
+struct spinlock_test_data {
+ struct percpu_lock lock;
+ struct test_data_entry c[CPU_SETSIZE];
+ int reps;
+};
+
+struct percpu_list_node {
+ intptr_t data;
+ struct percpu_list_node *next;
+};
+
+struct percpu_list_entry {
+ struct percpu_list_node *head;
+} __attribute__((aligned(128)));
+
+struct percpu_list {
+ struct percpu_list_entry c[CPU_SETSIZE];
+};
+
+/* A simple percpu spinlock. Returns the cpu lock was acquired on. */
+int rseq_this_cpu_lock(struct percpu_lock *lock)
+{
+ int cpu;
+
+ for (;;) {
+ int ret;
+
+ cpu = rseq_cpu_start();
+ ret = rseq_cmpeqv_storev(&lock->c[cpu].v,
+ 0, 1, cpu);
+ if (rseq_likely(!ret))
+ break;
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ /*
+ * Acquire semantic when taking lock after control dependency.
+ * Matches rseq_smp_store_release().
+ */
+ rseq_smp_acquire__after_ctrl_dep();
+ return cpu;
+}
+
+void rseq_percpu_unlock(struct percpu_lock *lock, int cpu)
+{
+ assert(lock->c[cpu].v == 1);
+ /*
+ * Release lock, with release semantic. Matches
+ * rseq_smp_acquire__after_ctrl_dep().
+ */
+ rseq_smp_store_release(&lock->c[cpu].v, 0);
+}
+
+void *test_percpu_spinlock_thread(void *arg)
+{
+ struct spinlock_test_data *data = arg;
+ int i, cpu;
+
+ if (rseq_register_current_thread()) {
+ fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ abort();
+ }
+ for (i = 0; i < data->reps; i++) {
+ cpu = rseq_this_cpu_lock(&data->lock);
+ data->c[cpu].count++;
+ rseq_percpu_unlock(&data->lock, cpu);
+ }
+ if (rseq_unregister_current_thread()) {
+ fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ abort();
+ }
+
+ return NULL;
+}
+
+/*
+ * A simple test which implements a sharded counter using a per-cpu
+ * lock. Obviously real applications might prefer to simply use a
+ * per-cpu increment; however, this is reasonable for a test and the
+ * lock can be extended to synchronize more complicated operations.
+ */
+void test_percpu_spinlock(void)
+{
+ const int num_threads = 200;
+ int i;
+ uint64_t sum;
+ pthread_t test_threads[num_threads];
+ struct spinlock_test_data data;
+
+ memset(&data, 0, sizeof(data));
+ data.reps = 5000;
+
+ for (i = 0; i < num_threads; i++)
+ pthread_create(&test_threads[i], NULL,
+ test_percpu_spinlock_thread, &data);
+
+ for (i = 0; i < num_threads; i++)
+ pthread_join(test_threads[i], NULL);
+
+ sum = 0;
+ for (i = 0; i < CPU_SETSIZE; i++)
+ sum += data.c[i].count;
+
+ assert(sum == (uint64_t)data.reps * num_threads);
+}
+
+void this_cpu_list_push(struct percpu_list *list,
+ struct percpu_list_node *node,
+ int *_cpu)
+{
+ int cpu;
+
+ for (;;) {
+ intptr_t *targetptr, newval, expect;
+ int ret;
+
+ cpu = rseq_cpu_start();
+ /* Load list->c[cpu].head with single-copy atomicity. */
+ expect = (intptr_t)RSEQ_READ_ONCE(list->c[cpu].head);
+ newval = (intptr_t)node;
+ targetptr = (intptr_t *)&list->c[cpu].head;
+ node->next = (struct percpu_list_node *)expect;
+ ret = rseq_cmpeqv_storev(targetptr, expect, newval, cpu);
+ if (rseq_likely(!ret))
+ break;
+ /* Retry if comparison fails or rseq aborts. */
+ }
+ if (_cpu)
+ *_cpu = cpu;
+}
+
+/*
+ * Unlike a traditional lock-less linked list; the availability of a
+ * rseq primitive allows us to implement pop without concerns over
+ * ABA-type races.
+ */
+struct percpu_list_node *this_cpu_list_pop(struct percpu_list *list,
+ int *_cpu)
+{
+ for (;;) {
+ struct percpu_list_node *head;
+ intptr_t *targetptr, expectnot, *load;
+ off_t offset;
+ int ret, cpu;
+
+ cpu = rseq_cpu_start();
+ targetptr = (intptr_t *)&list->c[cpu].head;
+ expectnot = (intptr_t)NULL;
+ offset = offsetof(struct percpu_list_node, next);
+ load = (intptr_t *)&head;
+ ret = rseq_cmpnev_storeoffp_load(targetptr, expectnot,
+ offset, load, cpu);
+ if (rseq_likely(!ret)) {
+ if (_cpu)
+ *_cpu = cpu;
+ return head;
+ }
+ if (ret > 0)
+ return NULL;
+ /* Retry if rseq aborts. */
+ }
+}
+
+/*
+ * __percpu_list_pop is not safe against concurrent accesses. Should
+ * only be used on lists that are not concurrently modified.
+ */
+struct percpu_list_node *__percpu_list_pop(struct percpu_list *list, int cpu)
+{
+ struct percpu_list_node *node;
+
+ node = list->c[cpu].head;
+ if (!node)
+ return NULL;
+ list->c[cpu].head = node->next;
+ return node;
+}
+
+void *test_percpu_list_thread(void *arg)
+{
+ int i;
+ struct percpu_list *list = (struct percpu_list *)arg;
+
+ if (rseq_register_current_thread()) {
+ fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ abort();
+ }
+
+ for (i = 0; i < 100000; i++) {
+ struct percpu_list_node *node;
+
+ node = this_cpu_list_pop(list, NULL);
+ sched_yield(); /* encourage shuffling */
+ if (node)
+ this_cpu_list_push(list, node, NULL);
+ }
+
+ if (rseq_unregister_current_thread()) {
+ fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ abort();
+ }
+
+ return NULL;
+}
+
+/* Simultaneous modification to a per-cpu linked list from many threads. */
+void test_percpu_list(void)
+{
+ int i, j;
+ uint64_t sum = 0, expected_sum = 0;
+ struct percpu_list list;
+ pthread_t test_threads[200];
+ cpu_set_t allowed_cpus;
+
+ memset(&list, 0, sizeof(list));
+
+ /* Generate list entries for every usable cpu. */
+ sched_getaffinity(0, sizeof(allowed_cpus), &allowed_cpus);
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+ for (j = 1; j <= 100; j++) {
+ struct percpu_list_node *node;
+
+ expected_sum += j;
+
+ node = malloc(sizeof(*node));
+ assert(node);
+ node->data = j;
+ node->next = list.c[i].head;
+ list.c[i].head = node;
+ }
+ }
+
+ for (i = 0; i < 200; i++)
+ pthread_create(&test_threads[i], NULL,
+ test_percpu_list_thread, &list);
+
+ for (i = 0; i < 200; i++)
+ pthread_join(test_threads[i], NULL);
+
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ struct percpu_list_node *node;
+
+ if (!CPU_ISSET(i, &allowed_cpus))
+ continue;
+
+ while ((node = __percpu_list_pop(&list, i))) {
+ sum += node->data;
+ free(node);
+ }
+ }
+
+ /*
+ * All entries should now be accounted for (unless some external
+ * actor is interfering with our allowed affinity while this
+ * test is running).
+ */
+ assert(sum == expected_sum);
+}
+
+int main(int argc, char **argv)
+{
+ if (rseq_register_current_thread()) {
+ fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ goto error;
+ }
+ printf("spinlock\n");
+ test_percpu_spinlock();
+ printf("percpu_list\n");
+ test_percpu_list();
+ if (rseq_unregister_current_thread()) {
+ fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ goto error;
+ }
+ return 0;
+
+error:
+ return -1;
+}
+
--
2.11.0
^ permalink raw reply related
* [PATCH 11/14] rseq: selftests: Provide basic test
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers, Shuah Khan
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
"basic_test" only asserts that RSEQ works moderately correctly. E.g.
that the CPUID pointer works.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-kselftest@vger.kernel.org
CC: linux-api@vger.kernel.org
---
tools/testing/selftests/rseq/basic_test.c | 56 +++++++++++++++++++++++++++++++
1 file changed, 56 insertions(+)
create mode 100644 tools/testing/selftests/rseq/basic_test.c
diff --git a/tools/testing/selftests/rseq/basic_test.c b/tools/testing/selftests/rseq/basic_test.c
new file mode 100644
index 000000000000..d8efbfb89193
--- /dev/null
+++ b/tools/testing/selftests/rseq/basic_test.c
@@ -0,0 +1,56 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Basic test coverage for critical regions and rseq_current_cpu().
+ */
+
+#define _GNU_SOURCE
+#include <assert.h>
+#include <sched.h>
+#include <signal.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/time.h>
+
+#include "rseq.h"
+
+void test_cpu_pointer(void)
+{
+ cpu_set_t affinity, test_affinity;
+ int i;
+
+ sched_getaffinity(0, sizeof(affinity), &affinity);
+ CPU_ZERO(&test_affinity);
+ for (i = 0; i < CPU_SETSIZE; i++) {
+ if (CPU_ISSET(i, &affinity)) {
+ CPU_SET(i, &test_affinity);
+ sched_setaffinity(0, sizeof(test_affinity),
+ &test_affinity);
+ assert(sched_getcpu() == i);
+ assert(rseq_current_cpu() == i);
+ assert(rseq_current_cpu_raw() == i);
+ assert(rseq_cpu_start() == i);
+ CPU_CLR(i, &test_affinity);
+ }
+ }
+ sched_setaffinity(0, sizeof(affinity), &affinity);
+}
+
+int main(int argc, char **argv)
+{
+ if (rseq_register_current_thread()) {
+ fprintf(stderr, "Error: rseq_register_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ goto init_thread_error;
+ }
+ printf("testing current cpu\n");
+ test_cpu_pointer();
+ if (rseq_unregister_current_thread()) {
+ fprintf(stderr, "Error: rseq_unregister_current_thread(...) failed(%d): %s\n",
+ errno, strerror(errno));
+ goto init_thread_error;
+ }
+ return 0;
+
+init_thread_error:
+ return -1;
+}
--
2.11.0
^ permalink raw reply related
* [PATCH 10/14] rseq: selftests: Provide rseq library (v5)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers, Shuah Khan
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
This rseq helper library provides a user-space API to the rseq()
system call.
The rseq fast-path exposes the instruction pointer addresses where the
rseq assembly blocks begin and end, as well as the associated abort
instruction pointer, in the __rseq_table section. This section allows
debuggers may know where to place breakpoints when single-stepping
through assembly blocks which may be aborted at any point by the kernel.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Shuah Khan <shuahkh@osg.samsung.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-kselftest@vger.kernel.org
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Provide abort-ip signature: The abort-ip signature is located just
before the abort-ip target. It is currently hardcoded, but a
user-space application could use the __rseq_table to iterate on all
abort-ip targets and use a random value as signature if needed in the
future.
- Add rseq_prepare_unload(): Libraries and JIT code using rseq critical
sections need to issue rseq_prepare_unload() on each thread at least
once before reclaim of struct rseq_cs.
- Use initial-exec TLS model, non-weak symbol: The initial-exec model is
signal-safe, whereas the global-dynamic model is not. Remove the
"weak" symbol attribute from the __rseq_abi in rseq.c. The rseq.so
library will have ownership of that symbol, and there is not reason for
an application or user library to try to define that symbol.
The expected use is to link against libreq.so, which owns and provide
that symbol.
- Set cpu_id to -2 on register error
- Add rseq_len syscall parameter, rseq_cs version
- Ensure disassember-friendly signature: x86 32/64 disassembler have a
hard time decoding the instruction stream after a bad instruction. Use
a nopl instruction to encode the signature. Suggested by Andy Lutomirski.
- Exercise parametrized tests variants in a shell scripts.
- Restartable sequences selftests: Remove use of event counter.
- Use cpu_id_start field: With the cpu_id_start field, the C
preparation phase of the fast-path does not need to compare cpu_id < 0
anymore.
- Signal-safe registration and refcounting: Allow libraries using
librseq.so to register it from signal handlers.
- Use OVERRIDE_TARGETS in makefile.
- Use "m" constraints for rseq_cs field.
Changes since v2:
- Update based on Thomas Gleixner's comments.
Changes since v3:
- Generate param_test_skip_fastpath and param_test_benchmark with
-DSKIP_FASTPATH and -DBENCHMARK (respectively). Add param_test_fastpath
to run_param_test.sh.
Changes since v4:
- Fold arm: workaround gcc asm size guess,
- Namespace barrier() -> rseq_barrier() in library header,
- Take into account coding style feedback from Peter Zijlstra,
- Split rseq selftests into logical commits.
---
tools/testing/selftests/rseq/rseq-arm.h | 715 +++++++++++++++++++
tools/testing/selftests/rseq/rseq-ppc.h | 671 ++++++++++++++++++
tools/testing/selftests/rseq/rseq-skip.h | 65 ++
tools/testing/selftests/rseq/rseq-x86.h | 1132 ++++++++++++++++++++++++++++++
tools/testing/selftests/rseq/rseq.c | 117 +++
tools/testing/selftests/rseq/rseq.h | 147 ++++
6 files changed, 2847 insertions(+)
create mode 100644 tools/testing/selftests/rseq/rseq-arm.h
create mode 100644 tools/testing/selftests/rseq/rseq-ppc.h
create mode 100644 tools/testing/selftests/rseq/rseq-skip.h
create mode 100644 tools/testing/selftests/rseq/rseq-x86.h
create mode 100644 tools/testing/selftests/rseq/rseq.c
create mode 100644 tools/testing/selftests/rseq/rseq.h
diff --git a/tools/testing/selftests/rseq/rseq-arm.h b/tools/testing/selftests/rseq/rseq-arm.h
new file mode 100644
index 000000000000..3b055f9aeaab
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq-arm.h
@@ -0,0 +1,715 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * rseq-arm.h
+ *
+ * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#define RSEQ_SIG 0x53053053
+
+#define rseq_smp_mb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
+#define rseq_smp_rmb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
+#define rseq_smp_wmb() __asm__ __volatile__ ("dmb" ::: "memory", "cc")
+
+#define rseq_smp_load_acquire(p) \
+__extension__ ({ \
+ __typeof(*p) ____p1 = RSEQ_READ_ONCE(*p); \
+ rseq_smp_mb(); \
+ ____p1; \
+})
+
+#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()
+
+#define rseq_smp_store_release(p, v) \
+do { \
+ rseq_smp_mb(); \
+ RSEQ_WRITE_ONCE(*p, v); \
+} while (0)
+
+#ifdef RSEQ_SKIP_FASTPATH
+#include "rseq-skip.h"
+#else /* !RSEQ_SKIP_FASTPATH */
+
+#define __RSEQ_ASM_DEFINE_TABLE(version, flags, start_ip, \
+ post_commit_offset, abort_ip) \
+ ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".balign 32\n\t" \
+ ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
+ ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_DEFINE_TABLE(start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_TABLE(0x0, 0x0, start_ip, \
+ (post_commit_ip - start_ip), abort_ip)
+
+#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
+ RSEQ_INJECT_ASM(1) \
+ "adr r0, " __rseq_str(cs_label) "\n\t" \
+ "str r0, %[" __rseq_str(rseq_cs) "]\n\t" \
+ __rseq_str(label) ":\n\t"
+
+#define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label) \
+ RSEQ_INJECT_ASM(2) \
+ "ldr r0, %[" __rseq_str(current_cpu_id) "]\n\t" \
+ "cmp %[" __rseq_str(cpu_id) "], r0\n\t" \
+ "bne " __rseq_str(label) "\n\t"
+
+#define __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, \
+ abort_label, version, flags, \
+ start_ip, post_commit_offset, abort_ip) \
+ __rseq_str(table_label) ":\n\t" \
+ ".word " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
+ ".word " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+ ".word " __rseq_str(RSEQ_SIG) "\n\t" \
+ __rseq_str(label) ":\n\t" \
+ teardown \
+ "b %l[" __rseq_str(abort_label) "]\n\t"
+
+#define RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, abort_label, \
+ start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_ABORT(table_label, label, teardown, \
+ abort_label, 0x0, 0x0, start_ip, \
+ (post_commit_ip - start_ip), abort_ip)
+
+#define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label) \
+ __rseq_str(label) ":\n\t" \
+ teardown \
+ "b %l[" __rseq_str(cmpfail_label) "]\n\t"
+
+#define rseq_workaround_gcc_asm_size_guess() __asm__ __volatile__("")
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[error2]\n\t"
+#endif
+ /* final store */
+ "str %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(5)
+ "b 5f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
+ "5:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
+ off_t voffp, intptr_t *load, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expectnot], r0\n\t"
+ "beq %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "ldr r0, %[v]\n\t"
+ "cmp %[expectnot], r0\n\t"
+ "beq %l[error2]\n\t"
+#endif
+ "str r0, %[load]\n\t"
+ "add r0, %[voffp]\n\t"
+ "ldr r0, [r0]\n\t"
+ /* final store */
+ "str r0, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(5)
+ "b 5f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
+ "5:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expectnot] "r" (expectnot),
+ [voffp] "Ir" (voffp),
+ [load] "m" (*load)
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_addv(intptr_t *v, intptr_t count, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+#endif
+ "ldr r0, %[v]\n\t"
+ "add r0, %[count]\n\t"
+ /* final store */
+ "str r0, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(4)
+ "b 5f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
+ "5:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ [v] "m" (*v),
+ [count] "Ir" (count)
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort
+#ifdef RSEQ_COMPARE_TWICE
+ , error1
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[error2]\n\t"
+#endif
+ /* try store */
+ "str %[newv2], %[v2]\n\t"
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ "str %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ "b 5f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
+ "5:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "r" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[error2]\n\t"
+#endif
+ /* try store */
+ "str %[newv2], %[v2]\n\t"
+ RSEQ_INJECT_ASM(5)
+ "dmb\n\t" /* full mb provides store-release */
+ /* final store */
+ "str %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ "b 5f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
+ "5:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "r" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t expect2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+ "ldr r0, %[v2]\n\t"
+ "cmp %[expect2], r0\n\t"
+ "bne %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(5)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne %l[error2]\n\t"
+ "ldr r0, %[v2]\n\t"
+ "cmp %[expect2], r0\n\t"
+ "bne %l[error3]\n\t"
+#endif
+ /* final store */
+ "str %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ "b 5f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4, "", abort, 1b, 2b, 4f)
+ "5:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* cmp2 input */
+ [v2] "m" (*v2),
+ [expect2] "r" (expect2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2, error3
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("1st expected value comparison failed");
+error3:
+ rseq_bug("2nd expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ uint32_t rseq_scratch[3];
+
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ "str %[src], %[rseq_scratch0]\n\t"
+ "str %[dst], %[rseq_scratch1]\n\t"
+ "str %[len], %[rseq_scratch2]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne 5f\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne 7f\n\t"
+#endif
+ /* try memcpy */
+ "cmp %[len], #0\n\t" \
+ "beq 333f\n\t" \
+ "222:\n\t" \
+ "ldrb %%r0, [%[src]]\n\t" \
+ "strb %%r0, [%[dst]]\n\t" \
+ "adds %[src], #1\n\t" \
+ "adds %[dst], #1\n\t" \
+ "subs %[len], #1\n\t" \
+ "bne 222b\n\t" \
+ "333:\n\t" \
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ "str %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t"
+ "b 8f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ abort, 1b, 2b, 4f)
+ RSEQ_ASM_DEFINE_CMPFAIL(5,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ cmpfail)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_DEFINE_CMPFAIL(6,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ error1)
+ RSEQ_ASM_DEFINE_CMPFAIL(7,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ error2)
+#endif
+ "8:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len),
+ [rseq_scratch0] "m" (rseq_scratch[0]),
+ [rseq_scratch1] "m" (rseq_scratch[1]),
+ [rseq_scratch2] "m" (rseq_scratch[2])
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_workaround_gcc_asm_size_guess();
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_workaround_gcc_asm_size_guess();
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ uint32_t rseq_scratch[3];
+
+ RSEQ_INJECT_C(9)
+
+ rseq_workaround_gcc_asm_size_guess();
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(1f, 2f, 4f) /* start, commit, abort */
+ "str %[src], %[rseq_scratch0]\n\t"
+ "str %[dst], %[rseq_scratch1]\n\t"
+ "str %[len], %[rseq_scratch2]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3f, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne 5f\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+ "ldr r0, %[v]\n\t"
+ "cmp %[expect], r0\n\t"
+ "bne 7f\n\t"
+#endif
+ /* try memcpy */
+ "cmp %[len], #0\n\t" \
+ "beq 333f\n\t" \
+ "222:\n\t" \
+ "ldrb %%r0, [%[src]]\n\t" \
+ "strb %%r0, [%[dst]]\n\t" \
+ "adds %[src], #1\n\t" \
+ "adds %[dst], #1\n\t" \
+ "subs %[len], #1\n\t" \
+ "bne 222b\n\t" \
+ "333:\n\t" \
+ RSEQ_INJECT_ASM(5)
+ "dmb\n\t" /* full mb provides store-release */
+ /* final store */
+ "str %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t"
+ "b 8f\n\t"
+ RSEQ_ASM_DEFINE_ABORT(3, 4,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ abort, 1b, 2b, 4f)
+ RSEQ_ASM_DEFINE_CMPFAIL(5,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ cmpfail)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_DEFINE_CMPFAIL(6,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ error1)
+ RSEQ_ASM_DEFINE_CMPFAIL(7,
+ /* teardown */
+ "ldr %[len], %[rseq_scratch2]\n\t"
+ "ldr %[dst], %[rseq_scratch1]\n\t"
+ "ldr %[src], %[rseq_scratch0]\n\t",
+ error2)
+#endif
+ "8:\n\t"
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len),
+ [rseq_scratch0] "m" (rseq_scratch[0]),
+ [rseq_scratch1] "m" (rseq_scratch[1]),
+ [rseq_scratch2] "m" (rseq_scratch[2])
+ RSEQ_INJECT_INPUT
+ : "r0", "memory", "cc"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ rseq_workaround_gcc_asm_size_guess();
+ return 0;
+abort:
+ rseq_workaround_gcc_asm_size_guess();
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ rseq_workaround_gcc_asm_size_guess();
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_workaround_gcc_asm_size_guess();
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_workaround_gcc_asm_size_guess();
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+#endif /* !RSEQ_SKIP_FASTPATH */
diff --git a/tools/testing/selftests/rseq/rseq-ppc.h b/tools/testing/selftests/rseq/rseq-ppc.h
new file mode 100644
index 000000000000..52630c9f42be
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq-ppc.h
@@ -0,0 +1,671 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * rseq-ppc.h
+ *
+ * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * (C) Copyright 2016-2018 - Boqun Feng <boqun.feng@gmail.com>
+ */
+
+#define RSEQ_SIG 0x53053053
+
+#define rseq_smp_mb() __asm__ __volatile__ ("sync" ::: "memory", "cc")
+#define rseq_smp_lwsync() __asm__ __volatile__ ("lwsync" ::: "memory", "cc")
+#define rseq_smp_rmb() rseq_smp_lwsync()
+#define rseq_smp_wmb() rseq_smp_lwsync()
+
+#define rseq_smp_load_acquire(p) \
+__extension__ ({ \
+ __typeof(*p) ____p1 = RSEQ_READ_ONCE(*p); \
+ rseq_smp_lwsync(); \
+ ____p1; \
+})
+
+#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_lwsync()
+
+#define rseq_smp_store_release(p, v) \
+do { \
+ rseq_smp_lwsync(); \
+ RSEQ_WRITE_ONCE(*p, v); \
+} while (0)
+
+#ifdef RSEQ_SKIP_FASTPATH
+#include "rseq-skip.h"
+#else /* !RSEQ_SKIP_FASTPATH */
+
+/*
+ * The __rseq_table section can be used by debuggers to better handle
+ * single-stepping through the restartable critical sections.
+ */
+
+#ifdef __PPC64__
+
+#define STORE_WORD "std "
+#define LOAD_WORD "ld "
+#define LOADX_WORD "ldx "
+#define CMP_WORD "cmpd "
+
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
+ start_ip, post_commit_offset, abort_ip) \
+ ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".balign 32\n\t" \
+ __rseq_str(label) ":\n\t" \
+ ".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
+ ".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
+ RSEQ_INJECT_ASM(1) \
+ "lis %%r17, (" __rseq_str(cs_label) ")@highest\n\t" \
+ "ori %%r17, %%r17, (" __rseq_str(cs_label) ")@higher\n\t" \
+ "rldicr %%r17, %%r17, 32, 31\n\t" \
+ "oris %%r17, %%r17, (" __rseq_str(cs_label) ")@high\n\t" \
+ "ori %%r17, %%r17, (" __rseq_str(cs_label) ")@l\n\t" \
+ "std %%r17, %[" __rseq_str(rseq_cs) "]\n\t" \
+ __rseq_str(label) ":\n\t"
+
+#else /* #ifdef __PPC64__ */
+
+#define STORE_WORD "stw "
+#define LOAD_WORD "lwz "
+#define LOADX_WORD "lwzx "
+#define CMP_WORD "cmpw "
+
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
+ start_ip, post_commit_offset, abort_ip) \
+ ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".balign 32\n\t" \
+ __rseq_str(label) ":\n\t" \
+ ".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
+ /* 32-bit only supported on BE */ \
+ ".long 0x0, " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
+ RSEQ_INJECT_ASM(1) \
+ "lis %%r17, (" __rseq_str(cs_label) ")@ha\n\t" \
+ "addi %%r17, %%r17, (" __rseq_str(cs_label) ")@l\n\t" \
+ "stw %%r17, %[" __rseq_str(rseq_cs) "]\n\t" \
+ __rseq_str(label) ":\n\t"
+
+#endif /* #ifdef __PPC64__ */
+
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
+ (post_commit_ip - start_ip), abort_ip)
+
+#define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label) \
+ RSEQ_INJECT_ASM(2) \
+ "lwz %%r17, %[" __rseq_str(current_cpu_id) "]\n\t" \
+ "cmpw cr7, %[" __rseq_str(cpu_id) "], %%r17\n\t" \
+ "bne- cr7, " __rseq_str(label) "\n\t"
+
+#define RSEQ_ASM_DEFINE_ABORT(label, abort_label) \
+ ".pushsection __rseq_failure, \"ax\"\n\t" \
+ ".long " __rseq_str(RSEQ_SIG) "\n\t" \
+ __rseq_str(label) ":\n\t" \
+ "b %l[" __rseq_str(abort_label) "]\n\t" \
+ ".popsection\n\t"
+
+/*
+ * RSEQ_ASM_OPs: asm operations for rseq
+ * RSEQ_ASM_OP_R_*: has hard-code registers in it
+ * RSEQ_ASM_OP_* (else): doesn't have hard-code registers(unless cr7)
+ */
+#define RSEQ_ASM_OP_CMPEQ(var, expect, label) \
+ LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t" \
+ CMP_WORD "cr7, %%r17, %[" __rseq_str(expect) "]\n\t" \
+ "bne- cr7, " __rseq_str(label) "\n\t"
+
+#define RSEQ_ASM_OP_CMPNE(var, expectnot, label) \
+ LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t" \
+ CMP_WORD "cr7, %%r17, %[" __rseq_str(expectnot) "]\n\t" \
+ "beq- cr7, " __rseq_str(label) "\n\t"
+
+#define RSEQ_ASM_OP_STORE(value, var) \
+ STORE_WORD "%[" __rseq_str(value) "], %[" __rseq_str(var) "]\n\t"
+
+/* Load @var to r17 */
+#define RSEQ_ASM_OP_R_LOAD(var) \
+ LOAD_WORD "%%r17, %[" __rseq_str(var) "]\n\t"
+
+/* Store r17 to @var */
+#define RSEQ_ASM_OP_R_STORE(var) \
+ STORE_WORD "%%r17, %[" __rseq_str(var) "]\n\t"
+
+/* Add @count to r17 */
+#define RSEQ_ASM_OP_R_ADD(count) \
+ "add %%r17, %[" __rseq_str(count) "], %%r17\n\t"
+
+/* Load (r17 + voffp) to r17 */
+#define RSEQ_ASM_OP_R_LOADX(voffp) \
+ LOADX_WORD "%%r17, %[" __rseq_str(voffp) "], %%r17\n\t"
+
+/* TODO: implement a faster memcpy. */
+#define RSEQ_ASM_OP_R_MEMCPY() \
+ "cmpdi %%r19, 0\n\t" \
+ "beq 333f\n\t" \
+ "addi %%r20, %%r20, -1\n\t" \
+ "addi %%r21, %%r21, -1\n\t" \
+ "222:\n\t" \
+ "lbzu %%r18, 1(%%r20)\n\t" \
+ "stbu %%r18, 1(%%r21)\n\t" \
+ "addi %%r19, %%r19, -1\n\t" \
+ "cmpdi %%r19, 0\n\t" \
+ "bne 222b\n\t" \
+ "333:\n\t" \
+
+#define RSEQ_ASM_OP_R_FINAL_STORE(var, post_commit_label) \
+ STORE_WORD "%%r17, %[" __rseq_str(var) "]\n\t" \
+ __rseq_str(post_commit_label) ":\n\t"
+
+#define RSEQ_ASM_OP_FINAL_STORE(value, var, post_commit_label) \
+ STORE_WORD "%[" __rseq_str(value) "], %[" __rseq_str(var) "]\n\t" \
+ __rseq_str(post_commit_label) ":\n\t"
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[error2])
+#endif
+ /* final store */
+ RSEQ_ASM_OP_FINAL_STORE(newv, v, 2)
+ RSEQ_INJECT_ASM(5)
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
+ off_t voffp, intptr_t *load, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v not equal to @expectnot */
+ RSEQ_ASM_OP_CMPNE(v, expectnot, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v not equal to @expectnot */
+ RSEQ_ASM_OP_CMPNE(v, expectnot, %l[error2])
+#endif
+ /* load the value of @v */
+ RSEQ_ASM_OP_R_LOAD(v)
+ /* store it in @load */
+ RSEQ_ASM_OP_R_STORE(load)
+ /* dereference voffp(v) */
+ RSEQ_ASM_OP_R_LOADX(voffp)
+ /* final store the value at voffp(v) */
+ RSEQ_ASM_OP_R_FINAL_STORE(v, 2)
+ RSEQ_INJECT_ASM(5)
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expectnot] "r" (expectnot),
+ [voffp] "b" (voffp),
+ [load] "m" (*load)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_addv(intptr_t *v, intptr_t count, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+#endif
+ /* load the value of @v */
+ RSEQ_ASM_OP_R_LOAD(v)
+ /* add @count to it */
+ RSEQ_ASM_OP_R_ADD(count)
+ /* final store */
+ RSEQ_ASM_OP_R_FINAL_STORE(v, 2)
+ RSEQ_INJECT_ASM(4)
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [count] "r" (count)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17"
+ RSEQ_INJECT_CLOBBER
+ : abort
+#ifdef RSEQ_COMPARE_TWICE
+ , error1
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[error2])
+#endif
+ /* try store */
+ RSEQ_ASM_OP_STORE(newv2, v2)
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ RSEQ_ASM_OP_FINAL_STORE(newv, v, 2)
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "r" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[error2])
+#endif
+ /* try store */
+ RSEQ_ASM_OP_STORE(newv2, v2)
+ RSEQ_INJECT_ASM(5)
+ /* for 'release' */
+ "lwsync\n\t"
+ /* final store */
+ RSEQ_ASM_OP_FINAL_STORE(newv, v, 2)
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "r" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t expect2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+ /* cmp @v2 equal to @expct2 */
+ RSEQ_ASM_OP_CMPEQ(v2, expect2, %l[cmpfail])
+ RSEQ_INJECT_ASM(5)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[error2])
+ /* cmp @v2 equal to @expct2 */
+ RSEQ_ASM_OP_CMPEQ(v2, expect2, %l[error3])
+#endif
+ /* final store */
+ RSEQ_ASM_OP_FINAL_STORE(newv, v, 2)
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* cmp2 input */
+ [v2] "m" (*v2),
+ [expect2] "r" (expect2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2, error3
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("1st expected value comparison failed");
+error3:
+ rseq_bug("2nd expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* setup for mempcy */
+ "mr %%r19, %[len]\n\t"
+ "mr %%r20, %[src]\n\t"
+ "mr %%r21, %[dst]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[error2])
+#endif
+ /* try memcpy */
+ RSEQ_ASM_OP_R_MEMCPY()
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ RSEQ_ASM_OP_FINAL_STORE(newv, v, 2)
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17", "r18", "r19", "r20", "r21"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* setup for mempcy */
+ "mr %%r19, %[len]\n\t"
+ "mr %%r20, %[src]\n\t"
+ "mr %%r21, %[dst]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[cmpfail])
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ /* cmp cpuid */
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ /* cmp @v equal to @expect */
+ RSEQ_ASM_OP_CMPEQ(v, expect, %l[error2])
+#endif
+ /* try memcpy */
+ RSEQ_ASM_OP_R_MEMCPY()
+ RSEQ_INJECT_ASM(5)
+ /* for 'release' */
+ "lwsync\n\t"
+ /* final store */
+ RSEQ_ASM_OP_FINAL_STORE(newv, v, 2)
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ RSEQ_ASM_DEFINE_ABORT(4, abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len)
+ RSEQ_INJECT_INPUT
+ : "memory", "cc", "r17", "r18", "r19", "r20", "r21"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+#undef STORE_WORD
+#undef LOAD_WORD
+#undef LOADX_WORD
+#undef CMP_WORD
+
+#endif /* !RSEQ_SKIP_FASTPATH */
diff --git a/tools/testing/selftests/rseq/rseq-skip.h b/tools/testing/selftests/rseq/rseq-skip.h
new file mode 100644
index 000000000000..72750b5905a9
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq-skip.h
@@ -0,0 +1,65 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * rseq-skip.h
+ *
+ * (C) Copyright 2017-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
+ off_t voffp, intptr_t *load, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_addv(intptr_t *v, intptr_t count, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t expect2,
+ intptr_t newv, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ return -1;
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ return -1;
+}
diff --git a/tools/testing/selftests/rseq/rseq-x86.h b/tools/testing/selftests/rseq/rseq-x86.h
new file mode 100644
index 000000000000..089410a314e9
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq-x86.h
@@ -0,0 +1,1132 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * rseq-x86.h
+ *
+ * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <stdint.h>
+
+#define RSEQ_SIG 0x53053053
+
+#ifdef __x86_64__
+
+#define rseq_smp_mb() \
+ __asm__ __volatile__ ("lock; addl $0,-128(%%rsp)" ::: "memory", "cc")
+#define rseq_smp_rmb() rseq_barrier()
+#define rseq_smp_wmb() rseq_barrier()
+
+#define rseq_smp_load_acquire(p) \
+__extension__ ({ \
+ __typeof(*p) ____p1 = RSEQ_READ_ONCE(*p); \
+ rseq_barrier(); \
+ ____p1; \
+})
+
+#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()
+
+#define rseq_smp_store_release(p, v) \
+do { \
+ rseq_barrier(); \
+ RSEQ_WRITE_ONCE(*p, v); \
+} while (0)
+
+#ifdef RSEQ_SKIP_FASTPATH
+#include "rseq-skip.h"
+#else /* !RSEQ_SKIP_FASTPATH */
+
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
+ start_ip, post_commit_offset, abort_ip) \
+ ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".balign 32\n\t" \
+ __rseq_str(label) ":\n\t" \
+ ".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
+ ".quad " __rseq_str(start_ip) ", " __rseq_str(post_commit_offset) ", " __rseq_str(abort_ip) "\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
+ (post_commit_ip - start_ip), abort_ip)
+
+#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
+ RSEQ_INJECT_ASM(1) \
+ "leaq " __rseq_str(cs_label) "(%%rip), %%rax\n\t" \
+ "movq %%rax, %[" __rseq_str(rseq_cs) "]\n\t" \
+ __rseq_str(label) ":\n\t"
+
+#define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label) \
+ RSEQ_INJECT_ASM(2) \
+ "cmpl %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
+ "jnz " __rseq_str(label) "\n\t"
+
+#define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label) \
+ ".pushsection __rseq_failure, \"ax\"\n\t" \
+ /* Disassembler-friendly signature: nopl <sig>(%rip). */\
+ ".byte 0x0f, 0x1f, 0x05\n\t" \
+ ".long " __rseq_str(RSEQ_SIG) "\n\t" \
+ __rseq_str(label) ":\n\t" \
+ teardown \
+ "jmp %l[" __rseq_str(abort_label) "]\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label) \
+ ".pushsection __rseq_failure, \"ax\"\n\t" \
+ __rseq_str(label) ":\n\t" \
+ teardown \
+ "jmp %l[" __rseq_str(cmpfail_label) "]\n\t" \
+ ".popsection\n\t"
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpq %[v], %[expect]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "cmpq %[v], %[expect]\n\t"
+ "jnz %l[error2]\n\t"
+#endif
+ /* final store */
+ "movq %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(5)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ : "memory", "cc", "rax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+/*
+ * Compare @v against @expectnot. When it does _not_ match, load @v
+ * into @load, and store the content of *@v + voffp into @v.
+ */
+static inline __attribute__((always_inline))
+int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
+ off_t voffp, intptr_t *load, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "movq %[v], %%rbx\n\t"
+ "cmpq %%rbx, %[expectnot]\n\t"
+ "je %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "movq %[v], %%rbx\n\t"
+ "cmpq %%rbx, %[expectnot]\n\t"
+ "je %l[error2]\n\t"
+#endif
+ "movq %%rbx, %[load]\n\t"
+ "addq %[voffp], %%rbx\n\t"
+ "movq (%%rbx), %%rbx\n\t"
+ /* final store */
+ "movq %%rbx, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(5)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expectnot] "r" (expectnot),
+ [voffp] "er" (voffp),
+ [load] "m" (*load)
+ : "memory", "cc", "rax", "rbx"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_addv(intptr_t *v, intptr_t count, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+#endif
+ /* final store */
+ "addq %[count], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(4)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [count] "er" (count)
+ : "memory", "cc", "rax"
+ RSEQ_INJECT_CLOBBER
+ : abort
+#ifdef RSEQ_COMPARE_TWICE
+ , error1
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpq %[v], %[expect]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "cmpq %[v], %[expect]\n\t"
+ "jnz %l[error2]\n\t"
+#endif
+ /* try store */
+ "movq %[newv2], %[v2]\n\t"
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ "movq %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "r" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ : "memory", "cc", "rax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+/* x86-64 is TSO. */
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ return rseq_cmpeqv_trystorev_storev(v, expect, v2, newv2, newv, cpu);
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t expect2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpq %[v], %[expect]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+ "cmpq %[v2], %[expect2]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(5)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "cmpq %[v], %[expect]\n\t"
+ "jnz %l[error2]\n\t"
+ "cmpq %[v2], %[expect2]\n\t"
+ "jnz %l[error3]\n\t"
+#endif
+ /* final store */
+ "movq %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* cmp2 input */
+ [v2] "m" (*v2),
+ [expect2] "r" (expect2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ : "memory", "cc", "rax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2, error3
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("1st expected value comparison failed");
+error3:
+ rseq_bug("2nd expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ uint64_t rseq_scratch[3];
+
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ "movq %[src], %[rseq_scratch0]\n\t"
+ "movq %[dst], %[rseq_scratch1]\n\t"
+ "movq %[len], %[rseq_scratch2]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpq %[v], %[expect]\n\t"
+ "jnz 5f\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+ "cmpq %[v], %[expect]\n\t"
+ "jnz 7f\n\t"
+#endif
+ /* try memcpy */
+ "test %[len], %[len]\n\t" \
+ "jz 333f\n\t" \
+ "222:\n\t" \
+ "movb (%[src]), %%al\n\t" \
+ "movb %%al, (%[dst])\n\t" \
+ "inc %[src]\n\t" \
+ "inc %[dst]\n\t" \
+ "dec %[len]\n\t" \
+ "jnz 222b\n\t" \
+ "333:\n\t" \
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ "movq %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ "movq %[rseq_scratch2], %[len]\n\t"
+ "movq %[rseq_scratch1], %[dst]\n\t"
+ "movq %[rseq_scratch0], %[src]\n\t"
+ RSEQ_ASM_DEFINE_ABORT(4,
+ "movq %[rseq_scratch2], %[len]\n\t"
+ "movq %[rseq_scratch1], %[dst]\n\t"
+ "movq %[rseq_scratch0], %[src]\n\t",
+ abort)
+ RSEQ_ASM_DEFINE_CMPFAIL(5,
+ "movq %[rseq_scratch2], %[len]\n\t"
+ "movq %[rseq_scratch1], %[dst]\n\t"
+ "movq %[rseq_scratch0], %[src]\n\t",
+ cmpfail)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_DEFINE_CMPFAIL(6,
+ "movq %[rseq_scratch2], %[len]\n\t"
+ "movq %[rseq_scratch1], %[dst]\n\t"
+ "movq %[rseq_scratch0], %[src]\n\t",
+ error1)
+ RSEQ_ASM_DEFINE_CMPFAIL(7,
+ "movq %[rseq_scratch2], %[len]\n\t"
+ "movq %[rseq_scratch1], %[dst]\n\t"
+ "movq %[rseq_scratch0], %[src]\n\t",
+ error2)
+#endif
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len),
+ [rseq_scratch0] "m" (rseq_scratch[0]),
+ [rseq_scratch1] "m" (rseq_scratch[1]),
+ [rseq_scratch2] "m" (rseq_scratch[2])
+ : "memory", "cc", "rax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+/* x86-64 is TSO. */
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ return rseq_cmpeqv_trymemcpy_storev(v, expect, dst, src, len,
+ newv, cpu);
+}
+
+#endif /* !RSEQ_SKIP_FASTPATH */
+
+#elif __i386__
+
+#define rseq_smp_mb() \
+ __asm__ __volatile__ ("lock; addl $0,-128(%%esp)" ::: "memory", "cc")
+#define rseq_smp_rmb() \
+ __asm__ __volatile__ ("lock; addl $0,-128(%%esp)" ::: "memory", "cc")
+#define rseq_smp_wmb() \
+ __asm__ __volatile__ ("lock; addl $0,-128(%%esp)" ::: "memory", "cc")
+
+#define rseq_smp_load_acquire(p) \
+__extension__ ({ \
+ __typeof(*p) ____p1 = RSEQ_READ_ONCE(*p); \
+ rseq_smp_mb(); \
+ ____p1; \
+})
+
+#define rseq_smp_acquire__after_ctrl_dep() rseq_smp_rmb()
+
+#define rseq_smp_store_release(p, v) \
+do { \
+ rseq_smp_mb(); \
+ RSEQ_WRITE_ONCE(*p, v); \
+} while (0)
+
+#ifdef RSEQ_SKIP_FASTPATH
+#include "rseq-skip.h"
+#else /* !RSEQ_SKIP_FASTPATH */
+
+/*
+ * Use eax as scratch register and take memory operands as input to
+ * lessen register pressure. Especially needed when compiling in O0.
+ */
+#define __RSEQ_ASM_DEFINE_TABLE(label, version, flags, \
+ start_ip, post_commit_offset, abort_ip) \
+ ".pushsection __rseq_table, \"aw\"\n\t" \
+ ".balign 32\n\t" \
+ __rseq_str(label) ":\n\t" \
+ ".long " __rseq_str(version) ", " __rseq_str(flags) "\n\t" \
+ ".long " __rseq_str(start_ip) ", 0x0, " __rseq_str(post_commit_offset) ", 0x0, " __rseq_str(abort_ip) ", 0x0\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_DEFINE_TABLE(label, start_ip, post_commit_ip, abort_ip) \
+ __RSEQ_ASM_DEFINE_TABLE(label, 0x0, 0x0, start_ip, \
+ (post_commit_ip - start_ip), abort_ip)
+
+#define RSEQ_ASM_STORE_RSEQ_CS(label, cs_label, rseq_cs) \
+ RSEQ_INJECT_ASM(1) \
+ "movl $" __rseq_str(cs_label) ", %[rseq_cs]\n\t" \
+ __rseq_str(label) ":\n\t"
+
+#define RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, label) \
+ RSEQ_INJECT_ASM(2) \
+ "cmpl %[" __rseq_str(cpu_id) "], %[" __rseq_str(current_cpu_id) "]\n\t" \
+ "jnz " __rseq_str(label) "\n\t"
+
+#define RSEQ_ASM_DEFINE_ABORT(label, teardown, abort_label) \
+ ".pushsection __rseq_failure, \"ax\"\n\t" \
+ /* Disassembler-friendly signature: nopl <sig>. */ \
+ ".byte 0x0f, 0x1f, 0x05\n\t" \
+ ".long " __rseq_str(RSEQ_SIG) "\n\t" \
+ __rseq_str(label) ":\n\t" \
+ teardown \
+ "jmp %l[" __rseq_str(abort_label) "]\n\t" \
+ ".popsection\n\t"
+
+#define RSEQ_ASM_DEFINE_CMPFAIL(label, teardown, cmpfail_label) \
+ ".pushsection __rseq_failure, \"ax\"\n\t" \
+ __rseq_str(label) ":\n\t" \
+ teardown \
+ "jmp %l[" __rseq_str(cmpfail_label) "]\n\t" \
+ ".popsection\n\t"
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_storev(intptr_t *v, intptr_t expect, intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpl %[v], %[expect]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "cmpl %[v], %[expect]\n\t"
+ "jnz %l[error2]\n\t"
+#endif
+ /* final store */
+ "movl %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(5)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+/*
+ * Compare @v against @expectnot. When it does _not_ match, load @v
+ * into @load, and store the content of *@v + voffp into @v.
+ */
+static inline __attribute__((always_inline))
+int rseq_cmpnev_storeoffp_load(intptr_t *v, intptr_t expectnot,
+ off_t voffp, intptr_t *load, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "movl %[v], %%ebx\n\t"
+ "cmpl %%ebx, %[expectnot]\n\t"
+ "je %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "movl %[v], %%ebx\n\t"
+ "cmpl %%ebx, %[expectnot]\n\t"
+ "je %l[error2]\n\t"
+#endif
+ "movl %%ebx, %[load]\n\t"
+ "addl %[voffp], %%ebx\n\t"
+ "movl (%%ebx), %%ebx\n\t"
+ /* final store */
+ "movl %%ebx, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(5)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expectnot] "r" (expectnot),
+ [voffp] "ir" (voffp),
+ [load] "m" (*load)
+ : "memory", "cc", "eax", "ebx"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_addv(intptr_t *v, intptr_t count, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+#endif
+ /* final store */
+ "addl %[count], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(4)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [count] "ir" (count)
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort
+#ifdef RSEQ_COMPARE_TWICE
+ , error1
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpl %[v], %[expect]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "cmpl %[v], %[expect]\n\t"
+ "jnz %l[error2]\n\t"
+#endif
+ /* try store */
+ "movl %[newv2], %%eax\n\t"
+ "movl %%eax, %[v2]\n\t"
+ RSEQ_INJECT_ASM(5)
+ /* final store */
+ "movl %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "m" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "r" (newv)
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trystorev_storev_release(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t newv2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "movl %[expect], %%eax\n\t"
+ "cmpl %[v], %%eax\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "movl %[expect], %%eax\n\t"
+ "cmpl %[v], %%eax\n\t"
+ "jnz %l[error2]\n\t"
+#endif
+ /* try store */
+ "movl %[newv2], %[v2]\n\t"
+ RSEQ_INJECT_ASM(5)
+ "lock; addl $0,-128(%%esp)\n\t"
+ /* final store */
+ "movl %[newv], %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* try store input */
+ [v2] "m" (*v2),
+ [newv2] "r" (newv2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "m" (expect),
+ [newv] "r" (newv)
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+
+}
+
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_cmpeqv_storev(intptr_t *v, intptr_t expect,
+ intptr_t *v2, intptr_t expect2,
+ intptr_t newv, int cpu)
+{
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "cmpl %[v], %[expect]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(4)
+ "cmpl %[expect2], %[v2]\n\t"
+ "jnz %l[cmpfail]\n\t"
+ RSEQ_INJECT_ASM(5)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, %l[error1])
+ "cmpl %[v], %[expect]\n\t"
+ "jnz %l[error2]\n\t"
+ "cmpl %[expect2], %[v2]\n\t"
+ "jnz %l[error3]\n\t"
+#endif
+ "movl %[newv], %%eax\n\t"
+ /* final store */
+ "movl %%eax, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ RSEQ_ASM_DEFINE_ABORT(4, "", abort)
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* cmp2 input */
+ [v2] "m" (*v2),
+ [expect2] "r" (expect2),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "r" (expect),
+ [newv] "m" (newv)
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2, error3
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("1st expected value comparison failed");
+error3:
+ rseq_bug("2nd expected value comparison failed");
+#endif
+}
+
+/* TODO: implement a faster memcpy. */
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ uint32_t rseq_scratch[3];
+
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ "movl %[src], %[rseq_scratch0]\n\t"
+ "movl %[dst], %[rseq_scratch1]\n\t"
+ "movl %[len], %[rseq_scratch2]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "movl %[expect], %%eax\n\t"
+ "cmpl %%eax, %[v]\n\t"
+ "jnz 5f\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+ "movl %[expect], %%eax\n\t"
+ "cmpl %%eax, %[v]\n\t"
+ "jnz 7f\n\t"
+#endif
+ /* try memcpy */
+ "test %[len], %[len]\n\t" \
+ "jz 333f\n\t" \
+ "222:\n\t" \
+ "movb (%[src]), %%al\n\t" \
+ "movb %%al, (%[dst])\n\t" \
+ "inc %[src]\n\t" \
+ "inc %[dst]\n\t" \
+ "dec %[len]\n\t" \
+ "jnz 222b\n\t" \
+ "333:\n\t" \
+ RSEQ_INJECT_ASM(5)
+ "movl %[newv], %%eax\n\t"
+ /* final store */
+ "movl %%eax, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t"
+ RSEQ_ASM_DEFINE_ABORT(4,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ abort)
+ RSEQ_ASM_DEFINE_CMPFAIL(5,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ cmpfail)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_DEFINE_CMPFAIL(6,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ error1)
+ RSEQ_ASM_DEFINE_CMPFAIL(7,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ error2)
+#endif
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "m" (expect),
+ [newv] "m" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len),
+ [rseq_scratch0] "m" (rseq_scratch[0]),
+ [rseq_scratch1] "m" (rseq_scratch[1]),
+ [rseq_scratch2] "m" (rseq_scratch[2])
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+/* TODO: implement a faster memcpy. */
+static inline __attribute__((always_inline))
+int rseq_cmpeqv_trymemcpy_storev_release(intptr_t *v, intptr_t expect,
+ void *dst, void *src, size_t len,
+ intptr_t newv, int cpu)
+{
+ uint32_t rseq_scratch[3];
+
+ RSEQ_INJECT_C(9)
+
+ __asm__ __volatile__ goto (
+ RSEQ_ASM_DEFINE_TABLE(3, 1f, 2f, 4f) /* start, commit, abort */
+ "movl %[src], %[rseq_scratch0]\n\t"
+ "movl %[dst], %[rseq_scratch1]\n\t"
+ "movl %[len], %[rseq_scratch2]\n\t"
+ /* Start rseq by storing table entry pointer into rseq_cs. */
+ RSEQ_ASM_STORE_RSEQ_CS(1, 3b, rseq_cs)
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 4f)
+ RSEQ_INJECT_ASM(3)
+ "movl %[expect], %%eax\n\t"
+ "cmpl %%eax, %[v]\n\t"
+ "jnz 5f\n\t"
+ RSEQ_INJECT_ASM(4)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_CMP_CPU_ID(cpu_id, current_cpu_id, 6f)
+ "movl %[expect], %%eax\n\t"
+ "cmpl %%eax, %[v]\n\t"
+ "jnz 7f\n\t"
+#endif
+ /* try memcpy */
+ "test %[len], %[len]\n\t" \
+ "jz 333f\n\t" \
+ "222:\n\t" \
+ "movb (%[src]), %%al\n\t" \
+ "movb %%al, (%[dst])\n\t" \
+ "inc %[src]\n\t" \
+ "inc %[dst]\n\t" \
+ "dec %[len]\n\t" \
+ "jnz 222b\n\t" \
+ "333:\n\t" \
+ RSEQ_INJECT_ASM(5)
+ "lock; addl $0,-128(%%esp)\n\t"
+ "movl %[newv], %%eax\n\t"
+ /* final store */
+ "movl %%eax, %[v]\n\t"
+ "2:\n\t"
+ RSEQ_INJECT_ASM(6)
+ /* teardown */
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t"
+ RSEQ_ASM_DEFINE_ABORT(4,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ abort)
+ RSEQ_ASM_DEFINE_CMPFAIL(5,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ cmpfail)
+#ifdef RSEQ_COMPARE_TWICE
+ RSEQ_ASM_DEFINE_CMPFAIL(6,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ error1)
+ RSEQ_ASM_DEFINE_CMPFAIL(7,
+ "movl %[rseq_scratch2], %[len]\n\t"
+ "movl %[rseq_scratch1], %[dst]\n\t"
+ "movl %[rseq_scratch0], %[src]\n\t",
+ error2)
+#endif
+ : /* gcc asm goto does not allow outputs */
+ : [cpu_id] "r" (cpu),
+ [current_cpu_id] "m" (__rseq_abi.cpu_id),
+ [rseq_cs] "m" (__rseq_abi.rseq_cs),
+ /* final store input */
+ [v] "m" (*v),
+ [expect] "m" (expect),
+ [newv] "m" (newv),
+ /* try memcpy input */
+ [dst] "r" (dst),
+ [src] "r" (src),
+ [len] "r" (len),
+ [rseq_scratch0] "m" (rseq_scratch[0]),
+ [rseq_scratch1] "m" (rseq_scratch[1]),
+ [rseq_scratch2] "m" (rseq_scratch[2])
+ : "memory", "cc", "eax"
+ RSEQ_INJECT_CLOBBER
+ : abort, cmpfail
+#ifdef RSEQ_COMPARE_TWICE
+ , error1, error2
+#endif
+ );
+ return 0;
+abort:
+ RSEQ_INJECT_FAILED
+ return -1;
+cmpfail:
+ return 1;
+#ifdef RSEQ_COMPARE_TWICE
+error1:
+ rseq_bug("cpu_id comparison failed");
+error2:
+ rseq_bug("expected value comparison failed");
+#endif
+}
+
+#endif /* !RSEQ_SKIP_FASTPATH */
+
+#endif
diff --git a/tools/testing/selftests/rseq/rseq.c b/tools/testing/selftests/rseq/rseq.c
new file mode 100644
index 000000000000..4847e97ed049
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq.c
@@ -0,0 +1,117 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * rseq.c
+ *
+ * Copyright (C) 2016 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ */
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <sched.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <syscall.h>
+#include <assert.h>
+#include <signal.h>
+
+#include "rseq.h"
+
+#define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]))
+
+__attribute__((tls_model("initial-exec"))) __thread
+volatile struct rseq __rseq_abi = {
+ .cpu_id = RSEQ_CPU_ID_UNINITIALIZED,
+};
+
+static __attribute__((tls_model("initial-exec"))) __thread
+volatile int refcount;
+
+static void signal_off_save(sigset_t *oldset)
+{
+ sigset_t set;
+ int ret;
+
+ sigfillset(&set);
+ ret = pthread_sigmask(SIG_BLOCK, &set, oldset);
+ if (ret)
+ abort();
+}
+
+static void signal_restore(sigset_t oldset)
+{
+ int ret;
+
+ ret = pthread_sigmask(SIG_SETMASK, &oldset, NULL);
+ if (ret)
+ abort();
+}
+
+static int sys_rseq(volatile struct rseq *rseq_abi, uint32_t rseq_len,
+ int flags, uint32_t sig)
+{
+ return syscall(__NR_rseq, rseq_abi, rseq_len, flags, sig);
+}
+
+int rseq_register_current_thread(void)
+{
+ int rc, ret = 0;
+ sigset_t oldset;
+
+ signal_off_save(&oldset);
+ if (refcount++)
+ goto end;
+ rc = sys_rseq(&__rseq_abi, sizeof(struct rseq), 0, RSEQ_SIG);
+ if (!rc) {
+ assert(rseq_current_cpu_raw() >= 0);
+ goto end;
+ }
+ if (errno != EBUSY)
+ __rseq_abi.cpu_id = -2;
+ ret = -1;
+ refcount--;
+end:
+ signal_restore(oldset);
+ return ret;
+}
+
+int rseq_unregister_current_thread(void)
+{
+ int rc, ret = 0;
+ sigset_t oldset;
+
+ signal_off_save(&oldset);
+ if (--refcount)
+ goto end;
+ rc = sys_rseq(&__rseq_abi, sizeof(struct rseq),
+ RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
+ if (!rc)
+ goto end;
+ ret = -1;
+end:
+ signal_restore(oldset);
+ return ret;
+}
+
+int32_t rseq_fallback_current_cpu(void)
+{
+ int32_t cpu;
+
+ cpu = sched_getcpu();
+ if (cpu < 0) {
+ perror("sched_getcpu()");
+ abort();
+ }
+ return cpu;
+}
diff --git a/tools/testing/selftests/rseq/rseq.h b/tools/testing/selftests/rseq/rseq.h
new file mode 100644
index 000000000000..0a808575cbc4
--- /dev/null
+++ b/tools/testing/selftests/rseq/rseq.h
@@ -0,0 +1,147 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * rseq.h
+ *
+ * (C) Copyright 2016-2018 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#ifndef RSEQ_H
+#define RSEQ_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <pthread.h>
+#include <signal.h>
+#include <sched.h>
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <linux/rseq.h>
+
+/*
+ * Empty code injection macros, override when testing.
+ * It is important to consider that the ASM injection macros need to be
+ * fully reentrant (e.g. do not modify the stack).
+ */
+#ifndef RSEQ_INJECT_ASM
+#define RSEQ_INJECT_ASM(n)
+#endif
+
+#ifndef RSEQ_INJECT_C
+#define RSEQ_INJECT_C(n)
+#endif
+
+#ifndef RSEQ_INJECT_INPUT
+#define RSEQ_INJECT_INPUT
+#endif
+
+#ifndef RSEQ_INJECT_CLOBBER
+#define RSEQ_INJECT_CLOBBER
+#endif
+
+#ifndef RSEQ_INJECT_FAILED
+#define RSEQ_INJECT_FAILED
+#endif
+
+extern __thread volatile struct rseq __rseq_abi;
+
+#define rseq_likely(x) __builtin_expect(!!(x), 1)
+#define rseq_unlikely(x) __builtin_expect(!!(x), 0)
+#define rseq_barrier() __asm__ __volatile__("" : : : "memory")
+
+#define RSEQ_ACCESS_ONCE(x) (*(__volatile__ __typeof__(x) *)&(x))
+#define RSEQ_WRITE_ONCE(x, v) __extension__ ({ RSEQ_ACCESS_ONCE(x) = (v); })
+#define RSEQ_READ_ONCE(x) RSEQ_ACCESS_ONCE(x)
+
+#define __rseq_str_1(x) #x
+#define __rseq_str(x) __rseq_str_1(x)
+
+#define rseq_log(fmt, args...) \
+ fprintf(stderr, fmt "(in %s() at " __FILE__ ":" __rseq_str(__LINE__)"\n", \
+ ## args, __func__)
+
+#define rseq_bug(fmt, args...) \
+ do { \
+ rseq_log(fmt, ##args); \
+ abort(); \
+ } while (0)
+
+#if defined(__x86_64__) || defined(__i386__)
+#include <rseq-x86.h>
+#elif defined(__ARMEL__)
+#include <rseq-arm.h>
+#elif defined(__PPC__)
+#include <rseq-ppc.h>
+#else
+#error unsupported target
+#endif
+
+/*
+ * Register rseq for the current thread. This needs to be called once
+ * by any thread which uses restartable sequences, before they start
+ * using restartable sequences, to ensure restartable sequences
+ * succeed. A restartable sequence executed from a non-registered
+ * thread will always fail.
+ */
+int rseq_register_current_thread(void);
+
+/*
+ * Unregister rseq for current thread.
+ */
+int rseq_unregister_current_thread(void);
+
+/*
+ * Restartable sequence fallback for reading the current CPU number.
+ */
+int32_t rseq_fallback_current_cpu(void);
+
+/*
+ * Values returned can be either the current CPU number, -1 (rseq is
+ * uninitialized), or -2 (rseq initialization has failed).
+ */
+static inline int32_t rseq_current_cpu_raw(void)
+{
+ return RSEQ_ACCESS_ONCE(__rseq_abi.cpu_id);
+}
+
+/*
+ * Returns a possible CPU number, which is typically the current CPU.
+ * The returned CPU number can be used to prepare for an rseq critical
+ * section, which will confirm whether the cpu number is indeed the
+ * current one, and whether rseq is initialized.
+ *
+ * The CPU number returned by rseq_cpu_start should always be validated
+ * by passing it to a rseq asm sequence, or by comparing it to the
+ * return value of rseq_current_cpu_raw() if the rseq asm sequence
+ * does not need to be invoked.
+ */
+static inline uint32_t rseq_cpu_start(void)
+{
+ return RSEQ_ACCESS_ONCE(__rseq_abi.cpu_id_start);
+}
+
+static inline uint32_t rseq_current_cpu(void)
+{
+ int32_t cpu;
+
+ cpu = rseq_current_cpu_raw();
+ if (rseq_unlikely(cpu < 0))
+ cpu = rseq_fallback_current_cpu();
+ return cpu;
+}
+
+/*
+ * rseq_prepare_unload() should be invoked by each thread using rseq_finish*()
+ * at least once between their last rseq_finish*() and library unload of the
+ * library defining the rseq critical section (struct rseq_cs). This also
+ * applies to use of rseq in code generated by JIT: rseq_prepare_unload()
+ * should be invoked at least once by each thread using rseq_finish*() before
+ * reclaim of the memory holding the struct rseq_cs.
+ */
+static inline void rseq_prepare_unload(void)
+{
+ __rseq_abi.rseq_cs = 0;
+}
+
+#endif /* RSEQ_H_ */
--
2.11.0
^ permalink raw reply related
* [PATCH 09/14] selftests: lib.mk: Introduce OVERRIDE_TARGETS
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
linux-kselftest
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Introduce OVERRIDE_TARGETS to allow tests to express dependencies on
header files and .so, which require to override the selftests lib.mk
targets.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Shuah Khan <shuahkh@osg.samsung.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-kselftest@vger.kernel.org
CC: linux-api@vger.kernel.org
---
tools/testing/selftests/lib.mk | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/tools/testing/selftests/lib.mk b/tools/testing/selftests/lib.mk
index 195e9d4739a9..9fd57efae439 100644
--- a/tools/testing/selftests/lib.mk
+++ b/tools/testing/selftests/lib.mk
@@ -106,6 +106,9 @@ COMPILE.S = $(CC) $(ASFLAGS) $(CPPFLAGS) $(TARGET_ARCH) -c
LINK.S = $(CC) $(ASFLAGS) $(CPPFLAGS) $(LDFLAGS) $(TARGET_ARCH)
endif
+# Selftest makefiles can override those targets by setting
+# OVERRIDE_TARGETS = 1.
+ifeq ($(OVERRIDE_TARGETS),)
$(OUTPUT)/%:%.c
$(LINK.c) $^ $(LDLIBS) -o $@
@@ -114,5 +117,6 @@ $(OUTPUT)/%.o:%.S
$(OUTPUT)/%:%.S
$(LINK.S) $^ $(LDLIBS) -o $@
+endif
.PHONY: run_tests all clean install emit_tests
--
2.11.0
^ permalink raw reply related
* [PATCH 08/14] powerpc: Wire up restartable sequences system call
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Benjamin Herrenschmidt <benh>
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
From: Boqun Feng <boqun.feng@gmail.com>
Wire up the rseq system call on powerpc.
This provides an ABI improving the speed of a user-space getcpu
operation on powerpc by skipping the getcpu system call on the fast
path, as well as improving the speed of user-space operations on per-cpu
data compared to using load-reservation/store-conditional atomics.
TODO: wire up rseq_syscall() on return from system call. It is used with
CONFIG_DEBUG_RSEQ=y to ensure system calls are not issued within rseq critical
section
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/include/asm/systbl.h | 1 +
arch/powerpc/include/asm/unistd.h | 2 +-
arch/powerpc/include/uapi/asm/unistd.h | 1 +
3 files changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/systbl.h b/arch/powerpc/include/asm/systbl.h
index d61f9c96d916..45d4d37495fd 100644
--- a/arch/powerpc/include/asm/systbl.h
+++ b/arch/powerpc/include/asm/systbl.h
@@ -392,3 +392,4 @@ SYSCALL(statx)
SYSCALL(pkey_alloc)
SYSCALL(pkey_free)
SYSCALL(pkey_mprotect)
+SYSCALL(rseq)
diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index daf1ba97a00c..1e9708632dce 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -12,7 +12,7 @@
#include <uapi/asm/unistd.h>
-#define NR_syscalls 387
+#define NR_syscalls 388
#define __NR__exit __NR_exit
diff --git a/arch/powerpc/include/uapi/asm/unistd.h b/arch/powerpc/include/uapi/asm/unistd.h
index 389c36fd8299..ac5ba55066dd 100644
--- a/arch/powerpc/include/uapi/asm/unistd.h
+++ b/arch/powerpc/include/uapi/asm/unistd.h
@@ -398,5 +398,6 @@
#define __NR_pkey_alloc 384
#define __NR_pkey_free 385
#define __NR_pkey_mprotect 386
+#define __NR_rseq 387
#endif /* _UAPI_ASM_POWERPC_UNISTD_H_ */
--
2.11.0
^ permalink raw reply related
* [PATCH 07/14] powerpc: Add support for restartable sequences
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: Joel Fernandes, Will Deacon, Andi Kleen, Paul Mackerras,
H . Peter Anvin, Chris Lameter, Russell King, Andrew Hunter,
Ingo Molnar, Michael Kerrisk, Catalin Marinas, Paul Turner,
Josh Triplett, Steven Rostedt, Ben Maurer, Mathieu Desnoyers,
Thomas Gleixner, linux-api, linuxppc-dev, linux-kernel,
Andrew Morton, Linus Torvalds
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
From: Boqun Feng <boqun.feng@gmail.com>
Call the rseq_handle_notify_resume() function on return to userspace if
TIF_NOTIFY_RESUME thread flag is set.
Perform fixup on the pre-signal when a signal is delivered on top of a
restartable sequence critical section.
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <paulus@samba.org>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: Peter Zijlstra <peterz@infradead.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/kernel/signal.c | 3 +++
2 files changed, 4 insertions(+)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index c32a181a7cbb..ed21a777e8c6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -223,6 +223,7 @@ config PPC
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_VIRT_CPU_ACCOUNTING
select HAVE_IRQ_TIME_ACCOUNTING
+ select HAVE_RSEQ
select IRQ_DOMAIN
select IRQ_FORCED_THREADING
select MODULES_USE_ELF_RELA
diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index 61db86ecd318..d3bb3aaaf5ac 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -133,6 +133,8 @@ static void do_signal(struct task_struct *tsk)
/* Re-enable the breakpoints for the signal stack */
thread_change_pc(tsk, tsk->thread.regs);
+ rseq_signal_deliver(tsk->thread.regs);
+
if (is32) {
if (ksig.ka.sa.sa_flags & SA_SIGINFO)
ret = handle_rt_signal32(&ksig, oldset, tsk);
@@ -164,6 +166,7 @@ void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags)
if (thread_info_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(regs);
}
user_enter();
--
2.11.0
^ permalink raw reply related
* [PATCH 06/14] x86: Wire up restartable sequence system call
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Wire up the rseq system call on x86 32/64.
This provides an ABI improving the speed of a user-space getcpu
operation on x86 by removing the need to perform a function call, "lsl"
instruction, or system call on the fast path, as well as improving the
speed of user-space operations on per-cpu data.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-api@vger.kernel.org
---
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
2 files changed, 2 insertions(+)
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index d6b27dab1b30..db346da64947 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -396,3 +396,4 @@
382 i386 pkey_free sys_pkey_free __ia32_sys_pkey_free
383 i386 statx sys_statx __ia32_sys_statx
384 i386 arch_prctl sys_arch_prctl __ia32_compat_sys_arch_prctl
+385 i386 rseq sys_rseq __ia32_sys_rseq
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 4dfe42666d0c..41b082b125c3 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -341,6 +341,7 @@
330 common pkey_alloc __x64_sys_pkey_alloc
331 common pkey_free __x64_sys_pkey_free
332 common statx __x64_sys_statx
+333 common rseq __x64_sys_rseq
#
# x32-specific system call numbers start at 512 to avoid cache impact
--
2.11.0
^ permalink raw reply related
* [PATCH 05/14] x86: Add support for restartable sequences (v2)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Call the rseq_handle_notify_resume() function on return to userspace if
TIF_NOTIFY_RESUME thread flag is set.
Perform fixup on the pre-signal frame when a signal is delivered on top
of a restartable sequence critical section.
Check that system calls are not invoked from within rseq critical
sections by invoking rseq_signal() from syscall_return_slowpath().
With CONFIG_DEBUG_RSEQ, such behavior results in termination of the
process with SIGSEGV.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Call rseq_signal() when returning from a system call.
---
arch/x86/Kconfig | 1 +
arch/x86/entry/common.c | 3 +++
arch/x86/kernel/signal.c | 6 ++++++
3 files changed, 10 insertions(+)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index c07f492b871a..62e00a1a7cf7 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -180,6 +180,7 @@ config X86
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION
select HAVE_STACK_VALIDATION if X86_64
+ select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UNSTABLE_SCHED_CLOCK
select HAVE_USER_RETURN_NOTIFIER
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index fbf6a6c3fd2d..92190879b228 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -164,6 +164,7 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
if (cached_flags & _TIF_NOTIFY_RESUME) {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(regs);
}
if (cached_flags & _TIF_USER_RETURN_NOTIFY)
@@ -254,6 +255,8 @@ __visible inline void syscall_return_slowpath(struct pt_regs *regs)
WARN(irqs_disabled(), "syscall %ld left IRQs disabled", regs->orig_ax))
local_irq_enable();
+ rseq_syscall(regs);
+
/*
* First do one-time work. If these work items are enabled, we
* want to run them exactly once per syscall exit with IRQs on.
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index da270b95fe4d..445ca11ff863 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -688,6 +688,12 @@ setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs)
sigset_t *set = sigmask_to_save();
compat_sigset_t *cset = (compat_sigset_t *) set;
+ /*
+ * Increment event counter and perform fixup for the pre-signal
+ * frame.
+ */
+ rseq_signal_deliver(regs);
+
/* Set up the stack frame */
if (is_ia32_frame(ksig)) {
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
--
2.11.0
^ permalink raw reply related
* [PATCH 04/14] arm: Wire up restartable sequences system call
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Wire up the rseq system call on 32-bit ARM.
This provides an ABI improving the speed of a user-space getcpu
operation on ARM by skipping the getcpu system call on the fast path, as
well as improving the speed of user-space operations on per-cpu data
compared to using load-linked/store-conditional.
TODO: wire up rseq_syscall() on return from system call. It is used with
CONFIG_DEBUG_RSEQ=y to ensure system calls are not issued within rseq critical
section
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-api@vger.kernel.org
---
arch/arm/tools/syscall.tbl | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 0bb0e9c6376c..fbc74b5fa3ed 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -412,3 +412,4 @@
395 common pkey_alloc sys_pkey_alloc
396 common pkey_free sys_pkey_free
397 common statx sys_statx
+398 common rseq sys_rseq
--
2.11.0
^ permalink raw reply related
* [PATCH 03/14] arm: Add restartable sequences support
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Call the rseq_handle_notify_resume() function on return to
userspace if TIF_NOTIFY_RESUME thread flag is set.
Perform fixup on the pre-signal frame when a signal is delivered on top
of a restartable sequence critical section.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-api@vger.kernel.org
---
arch/arm/Kconfig | 1 +
arch/arm/kernel/signal.c | 7 +++++++
2 files changed, 8 insertions(+)
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index a7f8e7f4b88f..4f5c386631d4 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -91,6 +91,7 @@ config ARM
select HAVE_PERF_USER_STACK_DUMP
select HAVE_RCU_TABLE_FREE if (SMP && ARM_LPAE)
select HAVE_REGS_AND_STACK_ACCESS_API
+ select HAVE_RSEQ
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_UID16
select HAVE_VIRT_CPU_ACCOUNTING_GEN
diff --git a/arch/arm/kernel/signal.c b/arch/arm/kernel/signal.c
index bd8810d4acb3..5879ab3f53c1 100644
--- a/arch/arm/kernel/signal.c
+++ b/arch/arm/kernel/signal.c
@@ -541,6 +541,12 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs)
int ret;
/*
+ * Increment event counter and perform fixup for the pre-signal
+ * frame.
+ */
+ rseq_signal_deliver(regs);
+
+ /*
* Set up the stack frame
*/
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
@@ -660,6 +666,7 @@ do_work_pending(struct pt_regs *regs, unsigned int thread_flags, int syscall)
} else {
clear_thread_flag(TIF_NOTIFY_RESUME);
tracehook_notify_resume(regs);
+ rseq_handle_notify_resume(regs);
}
}
local_irq_disable();
--
2.11.0
^ permalink raw reply related
* [PATCH 02/14] rseq: Introduce restartable sequences system call (v13)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers,
Alexander Viro
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Expose a new system call allowing each thread to register one userspace
memory area to be used as an ABI between kernel and user-space for two
purposes: user-space restartable sequences and quick access to read the
current CPU number value from user-space.
* Restartable sequences (per-cpu atomics)
Restartables sequences allow user-space to perform update operations on
per-cpu data without requiring heavy-weight atomic operations.
The restartable critical sections (percpu atomics) work has been started
by Paul Turner and Andrew Hunter. It lets the kernel handle restart of
critical sections. [1] [2] The re-implementation proposed here brings a
few simplifications to the ABI which facilitates porting to other
architectures and speeds up the user-space fast path.
Here are benchmarks of various rseq use-cases.
Test hardware:
arm32: ARMv7 Processor rev 4 (v7l) "Cubietruck", 2-core
x86-64: Intel E5-2630 v3@2.40GHz, 16-core, hyperthreading
The following benchmarks were all performed on a single thread.
* Per-CPU statistic counter increment
getcpu+atomic (ns/op) rseq (ns/op) speedup
arm32: 344.0 31.4 11.0
x86-64: 15.3 2.0 7.7
* LTTng-UST: write event 32-bit header, 32-bit payload into tracer
per-cpu buffer
getcpu+atomic (ns/op) rseq (ns/op) speedup
arm32: 2502.0 2250.0 1.1
x86-64: 117.4 98.0 1.2
* liburcu percpu: lock-unlock pair, dereference, read/compare word
getcpu+atomic (ns/op) rseq (ns/op) speedup
arm32: 751.0 128.5 5.8
x86-64: 53.4 28.6 1.9
* jemalloc memory allocator adapted to use rseq
Using rseq with per-cpu memory pools in jemalloc at Facebook (based on
rseq 2016 implementation):
The production workload response-time has 1-2% gain avg. latency, and
the P99 overall latency drops by 2-3%.
* Reading the current CPU number
Speeding up reading the current CPU number on which the caller thread is
running is done by keeping the current CPU number up do date within the
cpu_id field of the memory area registered by the thread. This is done
by making scheduler preemption set the TIF_NOTIFY_RESUME flag on the
current thread. Upon return to user-space, a notify-resume handler
updates the current CPU value within the registered user-space memory
area. User-space can then read the current CPU number directly from
memory.
Keeping the current cpu id in a memory area shared between kernel and
user-space is an improvement over current mechanisms available to read
the current CPU number, which has the following benefits over
alternative approaches:
- 35x speedup on ARM vs system call through glibc
- 20x speedup on x86 compared to calling glibc, which calls vdso
executing a "lsl" instruction,
- 14x speedup on x86 compared to inlined "lsl" instruction,
- Unlike vdso approaches, this cpu_id value can be read from an inline
assembly, which makes it a useful building block for restartable
sequences.
- The approach of reading the cpu id through memory mapping shared
between kernel and user-space is portable (e.g. ARM), which is not the
case for the lsl-based x86 vdso.
On x86, yet another possible approach would be to use the gs segment
selector to point to user-space per-cpu data. This approach performs
similarly to the cpu id cache, but it has two disadvantages: it is
not portable, and it is incompatible with existing applications already
using the gs segment selector for other purposes.
Benchmarking various approaches for reading the current CPU number:
ARMv7 Processor rev 4 (v7l)
Machine model: Cubietruck
- Baseline (empty loop): 8.4 ns
- Read CPU from rseq cpu_id: 16.7 ns
- Read CPU from rseq cpu_id (lazy register): 19.8 ns
- glibc 2.19-0ubuntu6.6 getcpu: 301.8 ns
- getcpu system call: 234.9 ns
x86-64 Intel(R) Xeon(R) CPU E5-2630 v3 @ 2.40GHz:
- Baseline (empty loop): 0.8 ns
- Read CPU from rseq cpu_id: 0.8 ns
- Read CPU from rseq cpu_id (lazy register): 0.8 ns
- Read using gs segment selector: 0.8 ns
- "lsl" inline assembly: 13.0 ns
- glibc 2.19-0ubuntu6 getcpu: 16.6 ns
- getcpu system call: 53.9 ns
- Speed (benchmark taken on v8 of patchset)
Running 10 runs of hackbench -l 100000 seems to indicate, contrary to
expectations, that enabling CONFIG_RSEQ slightly accelerates the
scheduler:
Configuration: 2 sockets * 8-core Intel(R) Xeon(R) CPU E5-2630 v3 @
2.40GHz (directly on hardware, hyperthreading disabled in BIOS, energy
saving disabled in BIOS, turboboost disabled in BIOS, cpuidle.off=1
kernel parameter), with a Linux v4.6 defconfig+localyesconfig,
restartable sequences series applied.
* CONFIG_RSEQ=n
avg.: 41.37 s
std.dev.: 0.36 s
* CONFIG_RSEQ=y
avg.: 40.46 s
std.dev.: 0.33 s
- Size
On x86-64, between CONFIG_RSEQ=n/y, the text size increase of vmlinux is
567 bytes, and the data size increase of vmlinux is 5696 bytes.
[1] https://lwn.net/Articles/650333/
[2] http://www.linuxplumbersconf.org/2013/ocw/system/presentations/1695/original/LPC%20-%20PerCpu%20Atomics.pdf
Link: http://lkml.kernel.org/r/20151027235635.16059.11630.stgit@pjt-glaptop.roam.corp.google.com
Link: http://lkml.kernel.org/r/20150624222609.6116.86035.stgit@kitami.mtv.corp.google.com
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Paul Turner <pjt@google.com>
CC: Andrew Hunter <ahh@google.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Return -1, errno=EINVAL if cpu_cache pointer is not aligned on
sizeof(int32_t).
- Update man page to describe the pointer alignement requirements and
update atomicity guarantees.
- Add MAINTAINERS file GETCPU_CACHE entry.
- Remove dynamic memory allocation: go back to having a single
getcpu_cache entry per thread. Update documentation accordingly.
- Rebased on Linux 4.4.
Changes since v2:
- Introduce a "cmd" argument, along with an enum with GETCPU_CACHE_GET
and GETCPU_CACHE_SET. Introduce a uapi header linux/getcpu_cache.h
defining this enumeration.
- Split resume notifier architecture implementation from the system call
wire up in the following arch-specific patches.
- Man pages updates.
- Handle 32-bit compat pointers.
- Simplify handling of getcpu_cache GETCPU_CACHE_SET compiler barrier:
set the current cpu cache pointer before doing the cache update, and
set it back to NULL if the update fails. Setting it back to NULL on
error ensures that no resume notifier will trigger a SIGSEGV if a
migration happened concurrently.
Changes since v3:
- Fix __user annotations in compat code,
- Update memory ordering comments.
- Rebased on kernel v4.5-rc5.
Changes since v4:
- Inline getcpu_cache_fork, getcpu_cache_execve, and getcpu_cache_exit.
- Add new line between if() and switch() to improve readability.
- Added sched switch benchmarks (hackbench) and size overhead comparison
to change log.
Changes since v5:
- Rename "getcpu_cache" to "thread_local_abi", allowing to extend
this system call to cover future features such as restartable critical
sections. Generalizing this system call ensures that we can add
features similar to the cpu_id field within the same cache-line
without having to track one pointer per feature within the task
struct.
- Add a tlabi_nr parameter to the system call, thus allowing to extend
the ABI beyond the initial 64-byte structure by registering structures
with tlabi_nr greater than 0. The initial ABI structure is associated
with tlabi_nr 0.
- Rebased on kernel v4.5.
Changes since v6:
- Integrate "restartable sequences" v2 patchset from Paul Turner.
- Add handling of single-stepping purely in user-space, with a
fallback to locking after 2 rseq failures to ensure progress, and
by exposing a __rseq_table section to debuggers so they know where
to put breakpoints when dealing with rseq assembly blocks which
can be aborted at any point.
- make the code and ABI generic: porting the kernel implementation
simply requires to wire up the signal handler and return to user-space
hooks, and allocate the syscall number.
- extend testing with a fully configurable test program. See
param_spinlock_test -h for details.
- handling of rseq ENOSYS in user-space, also with a fallback
to locking.
- modify Paul Turner's rseq ABI to only require a single TLS store on
the user-space fast-path, removing the need to populate two additional
registers. This is made possible by introducing struct rseq_cs into
the ABI to describe a critical section start_ip, post_commit_ip, and
abort_ip.
- Rebased on kernel v4.7-rc7.
Changes since v7:
- Documentation updates.
- Integrated powerpc architecture support.
- Compare rseq critical section start_ip, allows shriking the user-space
fast-path code size.
- Added Peter Zijlstra, Paul E. McKenney and Boqun Feng as
co-maintainers.
- Added do_rseq2 and do_rseq_memcpy to test program helper library.
- Code cleanup based on review from Peter Zijlstra, Andy Lutomirski and
Boqun Feng.
- Rebase on kernel v4.8-rc2.
Changes since v8:
- clear rseq_cs even if non-nested. Speeds up user-space fast path by
removing the final "rseq_cs=NULL" assignment.
- add enum rseq_flags: critical sections and threads can set migration,
preemption and signal "disable" flags to inhibit rseq behavior.
- rseq_event_counter needs to be updated with a pre-increment: Otherwise
misses an increment after exec (when TLS and in-kernel states are
initially 0).
Changes since v9:
- Update changelog.
- Fold instrumentation patch.
- check abort-ip signature: Add a signature before the abort-ip landing
address. This signature is also received as a new parameter to the
rseq system call. The kernel uses it ensures that rseq cannot be used
as an exploit vector to redirect execution to arbitrary code.
- Use rseq pointer for both register and unregister. This is more
symmetric, and eventually allow supporting a linked list of rseq
struct per thread if needed in the future.
- Unregistration of a rseq structure is now done with
RSEQ_FLAG_UNREGISTER.
- Remove reference counting. Return "EBUSY" to the caller if rseq is
already registered for the current thread. This simplifies
implementation while still allowing user-space to perform lazy
registration in multi-lib use-cases. (suggested by Ben Maurer)
- Clear rseq_cs upon unregister.
- Set cpu_id back to -1 on unregister, so if rseq user libraries follow
an unregister, and they expect to lazily register rseq, they can do
so.
- Document rseq_cs clear requirement: JIT should reset the rseq_cs
pointer before reclaiming memory of rseq_cs structure.
- Introduce rseq_len syscall parameter, rseq_cs version field:
Allow keeping track of the registered rseq struct length, for future
extensions. Add rseq_cs version as first field. Will allow future
extensions.
- Use offset and unsigned arithmetic to save a branch: Save a
conditional branch when comparing instruction pointer against a
rseq_cs descriptor's address range by having post_commit_ip as an
offset from start_ip, and using unsigned integer comparison.
Suggested by Ben Maurer.
- Remove event counter from ABI. Suggested by Andy Lutomirski.
- Add INIT_ONSTACK macro: Introduce the
RSEQ_FIELD_u32_u64_INIT_ONSTACK() macros to ensure that users
correctly initialize the upper bits of RSEQ_FIELD_u32_u64() on their
stack to 0 on 32-bit architectures.
- Select MEMBARRIER: Allows user-space rseq fast-paths to use the value
of cpu_id field (inherently required by the rseq algorithm) to figure
out whether membarrier can be expected to be available.
This effectively allows user-space fast-paths to remove extra
comparisons and branch testing whether membarrier is enabled, and thus
whether a full barrier is required (e.g. in userspace RCU
implementation after rcu_read_lock/before rcu_read_unlock).
- Expose cpu_id_start field: Checking whether the (cpu_id < 0) in the C
preparation part of the rseq fast-path brings significant overhead at
least on arm32. We can remove this extra comparison by exposing two
distinct cpu_id fields in the rseq TLS:
The field cpu_id_start always contain a *possible* cpu number, although
it may not be the current one if, for instance, rseq is not initialized
for the current thread. cpu_id_start is meant to be used in the C code
for the pointer chasing to figure out which per-cpu data structure
should be passed to the rseq asm sequence.
The field cpu_id values -1 means rseq is not initialized, and -2 means
initialization failed. That field is used in the rseq asm sequence to
confirm that the cpu_id_start value was indeed the current cpu number.
It also ends up confirming that rseq is initialized for the current
thread, because values -1 and -2 will never match the cpu_id_start
possible cpu number values.
This allows checking the current CPU number and rseq initialization
state with a single comparison on the fast-path.
Changes since v10:
- Update rseq.c comment, removing reference to event_counter.
Changes since v11:
- Replace task struct rseq_preempt, rseq_signal, and rseq_migrate
bool by u32 rseq_event_mask.
- Add missing sys_rseq() asmlinkage declaration to
include/linux/syscalls.h.
- Copy event mask on process fork, set to 0 on exec and thread-fork.
- Cleanups based on review from Peter Zijlstra.
- Cleanups based on review from Thomas Gleixner.
- Fix: rseq_cs needs to be cleared only when:
- Nested over non-critical-section userspace code,
- Nested over rseq_cs _and_ handling abort.
Basically, we should never clear rseq_cs when the rseq resume to
userspace handler is called and it is not handling abort: the
problematic case is if any of the __get_user()/__put_user done
by the handler trigger a page fault (e.g. page protection
done by NUMA page migration work), which triggers preemption:
the next call to the rseq resume to userspace handler needs to
perform the abort.
- Perform rseq event mask updates atomically wrt preemption,
- Move rseq_migrate to __set_task_cpu(), thus catching migration
scenario that bypass set_task_cpu(): fork and wake_up_new_task.
- Merge content of rseq_sched_out into rseq_preempt. There is no
need to have two hook sites. Both setting the rseq event mask
preempt bit and setting the notify resume thread flag can be
done from rseq_preempt().
- Issue rseq_preempt() from fork(), thus ensuring that we handle
abort if needed.
Changes since v12:
- Disallow syscalls from rseq critical sections,
- Introduce CONFIG_DEBUG_RSEQ, which terminates processes misusing
rseq (e.g. doing a system call within a rseq critical section) with
SIGSEGV,
- Coding style cleanups based on feedback from Boqun Feng and Peter
Zijlstra.
Man page associated:
RSEQ(2) Linux Programmer's Manual RSEQ(2)
NAME
rseq - Restartable sequences and cpu number cache
SYNOPSIS
#include <linux/rseq.h>
int rseq(struct rseq * rseq, uint32_t rseq_len, int flags, uint32_t sig);
DESCRIPTION
The rseq() ABI accelerates user-space operations on per-cpu
data by defining a shared data structure ABI between each user-
space thread and the kernel.
It allows user-space to perform update operations on per-cpu
data without requiring heavy-weight atomic operations.
The term CPU used in this documentation refers to a hardware
execution context.
Restartable sequences are atomic with respect to preemption
(making it atomic with respect to other threads running on the
same CPU), as well as signal delivery (user-space execution
contexts nested over the same thread).
It is suited for update operations on per-cpu data.
It can be used on data structures shared between threads within
a process, and on data structures shared between threads across
different processes.
Some examples of operations that can be accelerated or improved
by this ABI:
· Memory allocator per-cpu free-lists,
· Querying the current CPU number,
· Incrementing per-CPU counters,
· Modifying data protected by per-CPU spinlocks,
· Inserting/removing elements in per-CPU linked-lists,
· Writing/reading per-CPU ring buffers content.
· Accurately reading performance monitoring unit counters with
respect to thread migration.
Restartable sequences must not perform system calls. Doing so
may result in termination of the process by a segmentation
fault.
The rseq argument is a pointer to the thread-local rseq struc‐
ture to be shared between kernel and user-space. A NULL rseq
value unregisters the current thread rseq structure.
The layout of struct rseq is as follows:
Structure alignment
This structure is aligned on multiples of 32 bytes.
Structure size
This structure is extensible. Its size is passed as
parameter to the rseq system call.
Fields
cpu_id_start
Optimistic cache of the CPU number on which the current
thread is running. Its value is guaranteed to always be
a possible CPU number, even when rseq is not initial‐
ized. The value it contains should always be confirmed
by reading the cpu_id field.
cpu_id
Cache of the CPU number on which the current thread is
running. -1 if uninitialized.
rseq_cs
The rseq_cs field is a pointer to a struct rseq_cs. Is
is NULL when no rseq assembly block critical section is
active for the current thread. Setting it to point to a
critical section descriptor (struct rseq_cs) marks the
beginning of the critical section.
flags
Flags indicating the restart behavior for the current
thread. This is mainly used for debugging purposes. Can
be either:
· RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
· RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
· RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
The layout of struct rseq_cs version 0 is as follows:
Structure alignment
This structure is aligned on multiples of 32 bytes.
Structure size
This structure has a fixed size of 32 bytes.
Fields
version
Version of this structure.
flags
Flags indicating the restart behavior of this structure.
Can be either:
· RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
· RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
· RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
start_ip
Instruction pointer address of the first instruction of
the sequence of consecutive assembly instructions.
post_commit_offset
Offset (from start_ip address) of the address after the
last instruction of the sequence of consecutive assembly
instructions.
abort_ip
Instruction pointer address where to move the execution
flow in case of abort of the sequence of consecutive
assembly instructions.
The rseq_len argument is the size of the struct rseq to regis‐
ter.
The flags argument is 0 for registration, and RSEQ_FLAG_UNREG‐
ISTER for unregistration.
The sig argument is the 32-bit signature to be expected before
the abort handler code.
A single library per process should keep the rseq structure in
a thread-local storage variable. The cpu_id field should be
initialized to -1, and the cpu_id_start field should be ini‐
tialized to a possible CPU value (typically 0).
Each thread is responsible for registering and unregistering
its rseq structure. No more than one rseq structure address can
be registered per thread at a given time.
In a typical usage scenario, the thread registering the rseq
structure will be performing loads and stores from/to that
structure. It is however also allowed to read that structure
from other threads. The rseq field updates performed by the
kernel provide relaxed atomicity semantics, which guarantee
that other threads performing relaxed atomic reads of the cpu
number cache will always observe a consistent value.
RETURN VALUE
A return value of 0 indicates success. On error, -1 is
returned, and errno is set appropriately.
ERRORS
EINVAL Either flags contains an invalid value, or rseq contains
an address which is not appropriately aligned, or
rseq_len contains a size that does not match the size
received on registration.
ENOSYS The rseq() system call is not implemented by this ker‐
nel.
EFAULT rseq is an invalid address.
EBUSY Restartable sequence is already registered for this
thread.
EPERM The sig argument on unregistration does not match the
signature received on registration.
VERSIONS
The rseq() system call was added in Linux 4.X (TODO).
CONFORMING TO
rseq() is Linux-specific.
SEE ALSO
sched_getcpu(3)
Linux 2017-11-06 RSEQ(2)
---
MAINTAINERS | 11 ++
arch/Kconfig | 7 +
fs/exec.c | 1 +
include/linux/sched.h | 134 +++++++++++++++++
include/linux/syscalls.h | 4 +-
include/trace/events/rseq.h | 57 +++++++
include/uapi/linux/rseq.h | 133 +++++++++++++++++
init/Kconfig | 23 +++
kernel/Makefile | 1 +
kernel/fork.c | 2 +
kernel/rseq.c | 357 ++++++++++++++++++++++++++++++++++++++++++++
kernel/sched/core.c | 2 +
kernel/sys_ni.c | 3 +
13 files changed, 734 insertions(+), 1 deletion(-)
create mode 100644 include/trace/events/rseq.h
create mode 100644 include/uapi/linux/rseq.h
create mode 100644 kernel/rseq.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 79bb02ff812f..4d61ce154dfc 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11981,6 +11981,17 @@ F: include/dt-bindings/reset/
F: include/linux/reset.h
F: include/linux/reset-controller.h
+RESTARTABLE SEQUENCES SUPPORT
+M: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+M: Peter Zijlstra <peterz@infradead.org>
+M: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
+M: Boqun Feng <boqun.feng@gmail.com>
+L: linux-kernel@vger.kernel.org
+S: Supported
+F: kernel/rseq.c
+F: include/uapi/linux/rseq.h
+F: include/trace/events/rseq.h
+
RFKILL
M: Johannes Berg <johannes@sipsolutions.net>
L: linux-wireless@vger.kernel.org
diff --git a/arch/Kconfig b/arch/Kconfig
index 8e0d665c8d53..43b5e103c1b2 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -272,6 +272,13 @@ config HAVE_REGS_AND_STACK_ACCESS_API
declared in asm/ptrace.h
For example the kprobes-based event tracer needs this API.
+config HAVE_RSEQ
+ bool
+ depends on HAVE_REGS_AND_STACK_ACCESS_API
+ help
+ This symbol should be selected by an architecture if it
+ supports an implementation of restartable sequences.
+
config HAVE_CLK
bool
help
diff --git a/fs/exec.c b/fs/exec.c
index 183059c427b9..2c3911612b22 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1822,6 +1822,7 @@ static int do_execveat_common(int fd, struct filename *filename,
current->fs->in_exec = 0;
current->in_execve = 0;
membarrier_execve(current);
+ rseq_execve(current);
acct_update_integrals(current);
task_numa_free(current);
free_bprm(bprm);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b3d697f3b573..496a0b25a42d 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -27,6 +27,7 @@
#include <linux/signal_types.h>
#include <linux/mm_types_task.h>
#include <linux/task_io_accounting.h>
+#include <linux/rseq.h>
/* task_struct member predeclarations (sorted alphabetically): */
struct audit_context;
@@ -1007,6 +1008,17 @@ struct task_struct {
unsigned long numa_pages_migrated;
#endif /* CONFIG_NUMA_BALANCING */
+#ifdef CONFIG_RSEQ
+ struct rseq __user *rseq;
+ u32 rseq_len;
+ u32 rseq_sig;
+ /*
+ * RmW on rseq_event_mask must be performed atomically
+ * with respect to preemption.
+ */
+ unsigned long rseq_event_mask;
+#endif
+
struct tlbflush_unmap_batch tlb_ubc;
struct rcu_head rcu;
@@ -1716,4 +1728,126 @@ extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
#define TASK_SIZE_OF(tsk) TASK_SIZE
#endif
+#ifdef CONFIG_RSEQ
+
+/*
+ * Map the event mask on the user-space ABI enum rseq_cs_flags
+ * for direct mask checks.
+ */
+enum rseq_event_mask_bits {
+ RSEQ_EVENT_PREEMPT_BIT = RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT,
+ RSEQ_EVENT_SIGNAL_BIT = RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT,
+ RSEQ_EVENT_MIGRATE_BIT = RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT,
+};
+
+enum rseq_event_mask {
+ RSEQ_EVENT_PREEMPT = (1U << RSEQ_EVENT_PREEMPT_BIT),
+ RSEQ_EVENT_SIGNAL = (1U << RSEQ_EVENT_SIGNAL_BIT),
+ RSEQ_EVENT_MIGRATE = (1U << RSEQ_EVENT_MIGRATE_BIT),
+};
+
+static inline void rseq_set_notify_resume(struct task_struct *t)
+{
+ if (t->rseq)
+ set_tsk_thread_flag(t, TIF_NOTIFY_RESUME);
+}
+
+void __rseq_handle_notify_resume(struct pt_regs *regs);
+
+static inline void rseq_handle_notify_resume(struct pt_regs *regs)
+{
+ if (current->rseq)
+ __rseq_handle_notify_resume(regs);
+}
+
+static inline void rseq_signal_deliver(struct pt_regs *regs)
+{
+ preempt_disable();
+ __set_bit(RSEQ_EVENT_SIGNAL_BIT, ¤t->rseq_event_mask);
+ preempt_enable();
+ rseq_handle_notify_resume(regs);
+}
+
+/* rseq_preempt() requires preemption to be disabled. */
+static inline void rseq_preempt(struct task_struct *t)
+{
+ __set_bit(RSEQ_EVENT_PREEMPT_BIT, &t->rseq_event_mask);
+ rseq_set_notify_resume(t);
+}
+
+/* rseq_migrate() requires preemption to be disabled. */
+static inline void rseq_migrate(struct task_struct *t)
+{
+ __set_bit(RSEQ_EVENT_MIGRATE_BIT, &t->rseq_event_mask);
+ rseq_set_notify_resume(t);
+}
+
+/*
+ * If parent process has a registered restartable sequences area, the
+ * child inherits. Only applies when forking a process, not a thread. In
+ * case a parent fork() in the middle of a restartable sequence, set the
+ * resume notifier to force the child to retry.
+ */
+static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
+{
+ if (clone_flags & CLONE_THREAD) {
+ t->rseq = NULL;
+ t->rseq_len = 0;
+ t->rseq_sig = 0;
+ t->rseq_event_mask = 0;
+ } else {
+ t->rseq = current->rseq;
+ t->rseq_len = current->rseq_len;
+ t->rseq_sig = current->rseq_sig;
+ t->rseq_event_mask = current->rseq_event_mask;
+ rseq_preempt(t);
+ }
+}
+
+static inline void rseq_execve(struct task_struct *t)
+{
+ t->rseq = NULL;
+ t->rseq_len = 0;
+ t->rseq_sig = 0;
+ t->rseq_event_mask = 0;
+}
+
+#else
+
+static inline void rseq_set_notify_resume(struct task_struct *t)
+{
+}
+static inline void rseq_handle_notify_resume(struct pt_regs *regs)
+{
+}
+static inline void rseq_signal_deliver(struct pt_regs *regs)
+{
+}
+static inline void rseq_preempt(struct task_struct *t)
+{
+}
+static inline void rseq_migrate(struct task_struct *t)
+{
+}
+static inline void rseq_fork(struct task_struct *t, unsigned long clone_flags)
+{
+}
+static inline void rseq_execve(struct task_struct *t)
+{
+}
+
+#endif
+
+#ifdef CONFIG_DEBUG_RSEQ
+
+void rseq_syscall(struct pt_regs *regs);
+
+#else
+
+static inline void rseq_syscall(struct pt_regs *regs)
+{
+}
+
+#endif
+
#endif
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 70fcda1a9049..a16d72c70f28 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -66,6 +66,7 @@ struct old_linux_dirent;
struct perf_event_attr;
struct file_handle;
struct sigaltstack;
+struct rseq;
union bpf_attr;
#include <linux/types.h>
@@ -890,7 +891,8 @@ asmlinkage long sys_pkey_alloc(unsigned long flags, unsigned long init_val);
asmlinkage long sys_pkey_free(int pkey);
asmlinkage long sys_statx(int dfd, const char __user *path, unsigned flags,
unsigned mask, struct statx __user *buffer);
-
+asmlinkage long sys_rseq(struct rseq __user *rseq, uint32_t rseq_len,
+ int flags, uint32_t sig);
/*
* Architecture-specific system calls
diff --git a/include/trace/events/rseq.h b/include/trace/events/rseq.h
new file mode 100644
index 000000000000..a04a64bc1a00
--- /dev/null
+++ b/include/trace/events/rseq.h
@@ -0,0 +1,57 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM rseq
+
+#if !defined(_TRACE_RSEQ_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_RSEQ_H
+
+#include <linux/tracepoint.h>
+#include <linux/types.h>
+
+TRACE_EVENT(rseq_update,
+
+ TP_PROTO(struct task_struct *t),
+
+ TP_ARGS(t),
+
+ TP_STRUCT__entry(
+ __field(s32, cpu_id)
+ ),
+
+ TP_fast_assign(
+ __entry->cpu_id = raw_smp_processor_id();
+ ),
+
+ TP_printk("cpu_id=%d", __entry->cpu_id)
+);
+
+TRACE_EVENT(rseq_ip_fixup,
+
+ TP_PROTO(unsigned long regs_ip, unsigned long start_ip,
+ unsigned long post_commit_offset, unsigned long abort_ip),
+
+ TP_ARGS(regs_ip, start_ip, post_commit_offset, abort_ip),
+
+ TP_STRUCT__entry(
+ __field(unsigned long, regs_ip)
+ __field(unsigned long, start_ip)
+ __field(unsigned long, post_commit_offset)
+ __field(unsigned long, abort_ip)
+ ),
+
+ TP_fast_assign(
+ __entry->regs_ip = regs_ip;
+ __entry->start_ip = start_ip;
+ __entry->post_commit_offset = post_commit_offset;
+ __entry->abort_ip = abort_ip;
+ ),
+
+ TP_printk("regs_ip=0x%lx start_ip=0x%lx post_commit_offset=%lu abort_ip=0x%lx",
+ __entry->regs_ip, __entry->start_ip,
+ __entry->post_commit_offset, __entry->abort_ip)
+);
+
+#endif /* _TRACE_SOCK_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/include/uapi/linux/rseq.h b/include/uapi/linux/rseq.h
new file mode 100644
index 000000000000..d620fa43756c
--- /dev/null
+++ b/include/uapi/linux/rseq.h
@@ -0,0 +1,133 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_RSEQ_H
+#define _UAPI_LINUX_RSEQ_H
+
+/*
+ * linux/rseq.h
+ *
+ * Restartable sequences system call API
+ *
+ * Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#ifdef __KERNEL__
+# include <linux/types.h>
+#else
+# include <stdint.h>
+#endif
+
+#include <linux/types_32_64.h>
+
+enum rseq_cpu_id_state {
+ RSEQ_CPU_ID_UNINITIALIZED = -1,
+ RSEQ_CPU_ID_REGISTRATION_FAILED = -2,
+};
+
+enum rseq_flags {
+ RSEQ_FLAG_UNREGISTER = (1 << 0),
+};
+
+enum rseq_cs_flags_bit {
+ RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT = 0,
+ RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT = 1,
+ RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT = 2,
+};
+
+enum rseq_cs_flags {
+ RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT =
+ (1U << RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT_BIT),
+ RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL =
+ (1U << RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL_BIT),
+ RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE =
+ (1U << RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE_BIT),
+};
+
+/*
+ * struct rseq_cs is aligned on 4 * 8 bytes to ensure it is always
+ * contained within a single cache-line. It is usually declared as
+ * link-time constant data.
+ */
+struct rseq_cs {
+ /* Version of this structure. */
+ __u32 version;
+ /* enum rseq_cs_flags */
+ __u32 flags;
+ LINUX_FIELD_u32_u64(start_ip);
+ /* Offset from start_ip. */
+ LINUX_FIELD_u32_u64(post_commit_offset);
+ LINUX_FIELD_u32_u64(abort_ip);
+} __attribute__((aligned(4 * sizeof(__u64))));
+
+/*
+ * struct rseq is aligned on 4 * 8 bytes to ensure it is always
+ * contained within a single cache-line.
+ *
+ * A single struct rseq per thread is allowed.
+ */
+struct rseq {
+ /*
+ * Restartable sequences cpu_id_start field. Updated by the
+ * kernel, and read by user-space with single-copy atomicity
+ * semantics. Aligned on 32-bit. Always contains a value in the
+ * range of possible CPUs, although the value may not be the
+ * actual current CPU (e.g. if rseq is not initialized). This
+ * CPU number value should always be compared against the value
+ * of the cpu_id field before performing a rseq commit or
+ * returning a value read from a data structure indexed using
+ * the cpu_id_start value.
+ */
+ __u32 cpu_id_start;
+ /*
+ * Restartable sequences cpu_id field. Updated by the kernel,
+ * and read by user-space with single-copy atomicity semantics.
+ * Aligned on 32-bit. Values RSEQ_CPU_ID_UNINITIALIZED and
+ * RSEQ_CPU_ID_REGISTRATION_FAILED have a special semantic: the
+ * former means "rseq uninitialized", and latter means "rseq
+ * initialization failed". This value is meant to be read within
+ * rseq critical sections and compared with the cpu_id_start
+ * value previously read, before performing the commit instruction,
+ * or read and compared with the cpu_id_start value before returning
+ * a value loaded from a data structure indexed using the
+ * cpu_id_start value.
+ */
+ __u32 cpu_id;
+ /*
+ * Restartable sequences rseq_cs field.
+ *
+ * Contains NULL when no critical section is active for the current
+ * thread, or holds a pointer to the currently active struct rseq_cs.
+ *
+ * Updated by user-space, which sets the address of the currently
+ * active rseq_cs at the beginning of assembly instruction sequence
+ * block, and set to NULL by the kernel when it restarts an assembly
+ * instruction sequence block, as well as when the kernel detects that
+ * it is preempting or delivering a signal outside of the range
+ * targeted by the rseq_cs. Also needs to be set to NULL by user-space
+ * before reclaiming memory that contains the targeted struct rseq_cs.
+ *
+ * Read and set by the kernel with single-copy atomicity semantics.
+ * Set by user-space with single-copy atomicity semantics. Aligned
+ * on 64-bit.
+ */
+ LINUX_FIELD_u32_u64(rseq_cs);
+ /*
+ * - RSEQ_DISABLE flag:
+ *
+ * Fallback fast-track flag for single-stepping.
+ * Set by user-space if lack of progress is detected.
+ * Cleared by user-space after rseq finish.
+ * Read by the kernel.
+ * - RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT
+ * Inhibit instruction sequence block restart and event
+ * counter increment on preemption for this thread.
+ * - RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL
+ * Inhibit instruction sequence block restart and event
+ * counter increment on signal delivery for this thread.
+ * - RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE
+ * Inhibit instruction sequence block restart and event
+ * counter increment on migration for this thread.
+ */
+ __u32 flags;
+} __attribute__((aligned(4 * sizeof(__u64))));
+
+#endif /* _UAPI_LINUX_RSEQ_H */
diff --git a/init/Kconfig b/init/Kconfig
index f013afc74b11..2f7ff760870e 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1417,6 +1417,29 @@ config ARCH_HAS_MEMBARRIER_CALLBACKS
config ARCH_HAS_MEMBARRIER_SYNC_CORE
bool
+config RSEQ
+ bool "Enable rseq() system call" if EXPERT
+ default y
+ depends on HAVE_RSEQ
+ select MEMBARRIER
+ help
+ Enable the restartable sequences system call. It provides a
+ user-space cache for the current CPU number value, which
+ speeds up getting the current CPU number from user-space,
+ as well as an ABI to speed up user-space operations on
+ per-CPU data.
+
+ If unsure, say Y.
+
+config DEBUG_RSEQ
+ default n
+ bool "Enabled debugging of rseq() system call" if EXPERT
+ depends on RSEQ && DEBUG_KERNEL
+ help
+ Enable extra debugging checks for the rseq system call.
+
+ If unsure, say N.
+
config EMBEDDED
bool "Embedded system"
option allnoconfig_y
diff --git a/kernel/Makefile b/kernel/Makefile
index f85ae5dfa474..7085c841c413 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -113,6 +113,7 @@ obj-$(CONFIG_CONTEXT_TRACKING) += context_tracking.o
obj-$(CONFIG_TORTURE_TEST) += torture.o
obj-$(CONFIG_HAS_IOMEM) += memremap.o
+obj-$(CONFIG_RSEQ) += rseq.o
$(obj)/configs.o: $(obj)/config_data.h
diff --git a/kernel/fork.c b/kernel/fork.c
index a5d21c42acfc..70992bfeba81 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1899,6 +1899,8 @@ static __latent_entropy struct task_struct *copy_process(
*/
copy_seccomp(p);
+ rseq_fork(p, clone_flags);
+
/*
* Process group and session signals need to be delivered to just the
* parent before the fork or both the parent and the child after the
diff --git a/kernel/rseq.c b/kernel/rseq.c
new file mode 100644
index 000000000000..ae306f90c514
--- /dev/null
+++ b/kernel/rseq.c
@@ -0,0 +1,357 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Restartable sequences system call
+ *
+ * Copyright (C) 2015, Google, Inc.,
+ * Paul Turner <pjt@google.com> and Andrew Hunter <ahh@google.com>
+ * Copyright (C) 2015-2018, EfficiOS Inc.,
+ * Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/uaccess.h>
+#include <linux/syscalls.h>
+#include <linux/rseq.h>
+#include <linux/types.h>
+#include <asm/ptrace.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/rseq.h>
+
+#define RSEQ_CS_PREEMPT_MIGRATE_FLAGS (RSEQ_CS_FLAG_NO_RESTART_ON_MIGRATE | \
+ RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT)
+
+/*
+ *
+ * Restartable sequences are a lightweight interface that allows
+ * user-level code to be executed atomically relative to scheduler
+ * preemption and signal delivery. Typically used for implementing
+ * per-cpu operations.
+ *
+ * It allows user-space to perform update operations on per-cpu data
+ * without requiring heavy-weight atomic operations.
+ *
+ * Detailed algorithm of rseq user-space assembly sequences:
+ *
+ * init(rseq_cs)
+ * cpu = TLS->rseq::cpu_id_start
+ * [1] TLS->rseq::rseq_cs = rseq_cs
+ * [start_ip] ----------------------------
+ * [2] if (cpu != TLS->rseq::cpu_id)
+ * goto abort_ip;
+ * [3] <last_instruction_in_cs>
+ * [post_commit_ip] ----------------------------
+ *
+ * The address of jump target abort_ip must be outside the critical
+ * region, i.e.:
+ *
+ * [abort_ip] < [start_ip] || [abort_ip] >= [post_commit_ip]
+ *
+ * Steps [2]-[3] (inclusive) need to be a sequence of instructions in
+ * userspace that can handle being interrupted between any of those
+ * instructions, and then resumed to the abort_ip.
+ *
+ * 1. Userspace stores the address of the struct rseq_cs assembly
+ * block descriptor into the rseq_cs field of the registered
+ * struct rseq TLS area. This update is performed through a single
+ * store within the inline assembly instruction sequence.
+ * [start_ip]
+ *
+ * 2. Userspace tests to check whether the current cpu_id field match
+ * the cpu number loaded before start_ip, branching to abort_ip
+ * in case of a mismatch.
+ *
+ * If the sequence is preempted or interrupted by a signal
+ * at or after start_ip and before post_commit_ip, then the kernel
+ * clears TLS->__rseq_abi::rseq_cs, and sets the user-space return
+ * ip to abort_ip before returning to user-space, so the preempted
+ * execution resumes at abort_ip.
+ *
+ * 3. Userspace critical section final instruction before
+ * post_commit_ip is the commit. The critical section is
+ * self-terminating.
+ * [post_commit_ip]
+ *
+ * 4. <success>
+ *
+ * On failure at [2], or if interrupted by preempt or signal delivery
+ * between [1] and [3]:
+ *
+ * [abort_ip]
+ * F1. <failure>
+ */
+
+static int rseq_update_cpu_id(struct task_struct *t)
+{
+ u32 cpu_id = raw_smp_processor_id();
+
+ if (__put_user(cpu_id, &t->rseq->cpu_id_start))
+ return -EFAULT;
+ if (__put_user(cpu_id, &t->rseq->cpu_id))
+ return -EFAULT;
+ trace_rseq_update(t);
+ return 0;
+}
+
+static int rseq_reset_rseq_cpu_id(struct task_struct *t)
+{
+ u32 cpu_id_start = 0, cpu_id = RSEQ_CPU_ID_UNINITIALIZED;
+
+ /*
+ * Reset cpu_id_start to its initial state (0).
+ */
+ if (__put_user(cpu_id_start, &t->rseq->cpu_id_start))
+ return -EFAULT;
+ /*
+ * Reset cpu_id to RSEQ_CPU_ID_UNINITIALIZED, so any user coming
+ * in after unregistration can figure out that rseq needs to be
+ * registered again.
+ */
+ if (__put_user(cpu_id, &t->rseq->cpu_id))
+ return -EFAULT;
+ return 0;
+}
+
+static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
+{
+ struct rseq_cs __user *urseq_cs;
+ unsigned long ptr;
+ u32 __user *usig;
+ u32 sig;
+ int ret;
+
+ ret = __get_user(ptr, &t->rseq->rseq_cs);
+ if (ret)
+ return ret;
+ if (!ptr) {
+ memset(rseq_cs, 0, sizeof(*rseq_cs));
+ return 0;
+ }
+ urseq_cs = (struct rseq_cs __user *)ptr;
+ if (copy_from_user(rseq_cs, urseq_cs, sizeof(*rseq_cs)))
+ return -EFAULT;
+ if (rseq_cs->version > 0)
+ return -EINVAL;
+
+ /* Ensure that abort_ip is not in the critical section. */
+ if (rseq_cs->abort_ip - rseq_cs->start_ip < rseq_cs->post_commit_offset)
+ return -EINVAL;
+
+ usig = (u32 __user *)(rseq_cs->abort_ip - sizeof(u32));
+ ret = get_user(sig, usig);
+ if (ret)
+ return ret;
+
+ if (current->rseq_sig != sig) {
+ printk_ratelimited(KERN_WARNING
+ "Possible attack attempt. Unexpected rseq signature 0x%x, expecting 0x%x (pid=%d, addr=%p).\n",
+ sig, current->rseq_sig, current->pid, usig);
+ return -EPERM;
+ }
+ return 0;
+}
+
+static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
+{
+ u32 flags, event_mask;
+ int ret;
+
+ /* Get thread flags. */
+ ret = __get_user(flags, &t->rseq->flags);
+ if (ret)
+ return ret;
+
+ /* Take critical section flags into account. */
+ flags |= cs_flags;
+
+ /*
+ * Restart on signal can only be inhibited when restart on
+ * preempt and restart on migrate are inhibited too. Otherwise,
+ * a preempted signal handler could fail to restart the prior
+ * execution context on sigreturn.
+ */
+ if (unlikely((flags & RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL) &&
+ (flags & RSEQ_CS_PREEMPT_MIGRATE_FLAGS) !=
+ RSEQ_CS_PREEMPT_MIGRATE_FLAGS))
+ return -EINVAL;
+
+ /*
+ * Load and clear event mask atomically with respect to
+ * scheduler preemption.
+ */
+ preempt_disable();
+ event_mask = t->rseq_event_mask;
+ t->rseq_event_mask = 0;
+ preempt_enable();
+
+ return !!(event_mask & ~flags);
+}
+
+static int clear_rseq_cs(struct task_struct *t)
+{
+ /*
+ * The rseq_cs field is set to NULL on preemption or signal
+ * delivery on top of rseq assembly block, as well as on top
+ * of code outside of the rseq assembly block. This performs
+ * a lazy clear of the rseq_cs field.
+ *
+ * Set rseq_cs to NULL with single-copy atomicity.
+ */
+ return __put_user(0UL, &t->rseq->rseq_cs);
+}
+
+/*
+ * Unsigned comparison will be true when ip >= start_ip, and when
+ * ip < start_ip + post_commit_offset.
+ */
+static bool in_rseq_cs(unsigned long ip, struct rseq_cs *rseq_cs)
+{
+ return ip - rseq_cs->start_ip < rseq_cs->post_commit_offset;
+}
+
+static int rseq_ip_fixup(struct pt_regs *regs)
+{
+ unsigned long ip = instruction_pointer(regs);
+ struct task_struct *t = current;
+ struct rseq_cs rseq_cs;
+ int ret;
+
+ ret = rseq_get_rseq_cs(t, &rseq_cs);
+ if (ret)
+ return ret;
+
+ /*
+ * Handle potentially not being within a critical section.
+ * If not nested over a rseq critical section, restart is useless.
+ * Clear the rseq_cs pointer and return.
+ */
+ if (!in_rseq_cs(ip, &rseq_cs))
+ return clear_rseq_cs(t);
+ ret = rseq_need_restart(t, rseq_cs.flags);
+ if (ret <= 0)
+ return ret;
+ ret = clear_rseq_cs(t);
+ if (ret)
+ return ret;
+ trace_rseq_ip_fixup(ip, rseq_cs.start_ip, rseq_cs.post_commit_offset,
+ rseq_cs.abort_ip);
+ instruction_pointer_set(regs, (unsigned long)rseq_cs.abort_ip);
+ return 0;
+}
+
+/*
+ * This resume handler must always be executed between any of:
+ * - preemption,
+ * - signal delivery,
+ * and return to user-space.
+ *
+ * This is how we can ensure that the entire rseq critical section,
+ * consisting of both the C part and the assembly instruction sequence,
+ * will issue the commit instruction only if executed atomically with
+ * respect to other threads scheduled on the same CPU, and with respect
+ * to signal handlers.
+ */
+void __rseq_handle_notify_resume(struct pt_regs *regs)
+{
+ struct task_struct *t = current;
+ int ret;
+
+ if (unlikely(t->flags & PF_EXITING))
+ return;
+ if (unlikely(!access_ok(VERIFY_WRITE, t->rseq, sizeof(*t->rseq))))
+ goto error;
+ ret = rseq_ip_fixup(regs);
+ if (unlikely(ret < 0))
+ goto error;
+ if (unlikely(rseq_update_cpu_id(t)))
+ goto error;
+ return;
+
+error:
+ force_sig(SIGSEGV, t);
+}
+
+#ifdef CONFIG_DEBUG_RSEQ
+
+/*
+ * Terminate the process if a syscall is issued within a restartable
+ * sequence.
+ */
+void rseq_syscall(struct pt_regs *regs)
+{
+ unsigned long ip = instruction_pointer(regs);
+ struct task_struct *t = current;
+ struct rseq_cs rseq_cs;
+
+ if (!t->rseq)
+ return;
+ if (!access_ok(VERIFY_READ, t->rseq, sizeof(*t->rseq)) ||
+ rseq_get_rseq_cs(t, &rseq_cs) || in_rseq_cs(ip, &rseq_cs))
+ force_sig(SIGSEGV, t);
+}
+
+#endif
+
+/*
+ * sys_rseq - setup restartable sequences for caller thread.
+ */
+SYSCALL_DEFINE4(rseq, struct rseq __user *, rseq, u32, rseq_len,
+ int, flags, u32, sig)
+{
+ int ret;
+
+ if (flags & RSEQ_FLAG_UNREGISTER) {
+ /* Unregister rseq for current thread. */
+ if (current->rseq != rseq || !current->rseq)
+ return -EINVAL;
+ if (current->rseq_len != rseq_len)
+ return -EINVAL;
+ if (current->rseq_sig != sig)
+ return -EPERM;
+ ret = rseq_reset_rseq_cpu_id(current);
+ if (ret)
+ return ret;
+ current->rseq = NULL;
+ current->rseq_len = 0;
+ current->rseq_sig = 0;
+ return 0;
+ }
+
+ if (unlikely(flags))
+ return -EINVAL;
+
+ if (current->rseq) {
+ /*
+ * If rseq is already registered, check whether
+ * the provided address differs from the prior
+ * one.
+ */
+ if (current->rseq != rseq || current->rseq_len != rseq_len)
+ return -EINVAL;
+ if (current->rseq_sig != sig)
+ return -EPERM;
+ /* Already registered. */
+ return -EBUSY;
+ }
+
+ /*
+ * If there was no rseq previously registered,
+ * ensure the provided rseq is properly aligned and valid.
+ */
+ if (!IS_ALIGNED((unsigned long)rseq, __alignof__(*rseq)) ||
+ rseq_len != sizeof(*rseq))
+ return -EINVAL;
+ if (!access_ok(VERIFY_WRITE, rseq, rseq_len))
+ return -EFAULT;
+ current->rseq = rseq;
+ current->rseq_len = rseq_len;
+ current->rseq_sig = sig;
+ /*
+ * If rseq was previously inactive, and has just been
+ * registered, ensure the cpu_id_start and cpu_id fields
+ * are updated before returning to user-space.
+ */
+ rseq_set_notify_resume(current);
+
+ return 0;
+}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5e10aaeebfcc..76d452ef2f0d 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1169,6 +1169,7 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
if (p->sched_class->migrate_task_rq)
p->sched_class->migrate_task_rq(p);
p->se.nr_migrations++;
+ rseq_migrate(p);
perf_event_task_migrate(p);
}
@@ -2634,6 +2635,7 @@ prepare_task_switch(struct rq *rq, struct task_struct *prev,
{
sched_info_switch(rq, prev, next);
perf_event_task_sched_out(prev, next);
+ rseq_preempt(prev);
fire_sched_out_preempt_notifiers(prev, next);
prepare_task(next);
prepare_arch_switch(next);
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 9791364925dc..22f4ef269959 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -430,3 +430,6 @@ COND_SYSCALL(setresgid16);
COND_SYSCALL(setresuid16);
COND_SYSCALL(setreuid16);
COND_SYSCALL(setuid16);
+
+/* restartable sequence */
+COND_SYSCALL(rseq);
--
2.11.0
^ permalink raw reply related
* [PATCH 01/14] uapi headers: Provide types_32_64.h (v2)
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers
In-Reply-To: <20180430224433.17407-1-mathieu.desnoyers@efficios.com>
Provide helper macros for fields which represent pointers in
kernel-userspace ABI. This facilitates handling of 32-bit
user-space by 64-bit kernels by defining those fields as
32-bit 0-padding and 32-bit integer on 32-bit architectures,
which allows the kernel to treat those as 64-bit integers.
The order of padding and 32-bit integer depends on the
endianness.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Paul Turner <pjt@google.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Andrew Hunter <ahh@google.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Andi Kleen <andi@firstfloor.org>
CC: Dave Watson <davejwatson@fb.com>
CC: Chris Lameter <cl@linux.com>
CC: Ingo Molnar <mingo@redhat.com>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Ben Maurer <bmaurer@fb.com>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Russell King <linux@arm.linux.org.uk>
CC: Catalin Marinas <catalin.marinas@arm.com>
CC: Will Deacon <will.deacon@arm.com>
CC: Michael Kerrisk <mtk.manpages@gmail.com>
CC: Boqun Feng <boqun.feng@gmail.com>
CC: linux-api@vger.kernel.org
---
Changes since v1:
- Public uapi headers use __u32 and __u64 rather than uint32_t and
uint64_t.
---
include/uapi/linux/types_32_64.h | 50 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 50 insertions(+)
create mode 100644 include/uapi/linux/types_32_64.h
diff --git a/include/uapi/linux/types_32_64.h b/include/uapi/linux/types_32_64.h
new file mode 100644
index 000000000000..0a87ace34a57
--- /dev/null
+++ b/include/uapi/linux/types_32_64.h
@@ -0,0 +1,50 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+#ifndef _UAPI_LINUX_TYPES_32_64_H
+#define _UAPI_LINUX_TYPES_32_64_H
+
+/*
+ * linux/types_32_64.h
+ *
+ * Integer type declaration for pointers across 32-bit and 64-bit systems.
+ *
+ * Copyright (c) 2015-2018 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ */
+
+#ifdef __KERNEL__
+# include <linux/types.h>
+#else
+# include <stdint.h>
+#endif
+
+#include <asm/byteorder.h>
+
+#ifdef __BYTE_ORDER
+# if (__BYTE_ORDER == __BIG_ENDIAN)
+# define LINUX_BYTE_ORDER_BIG_ENDIAN
+# else
+# define LINUX_BYTE_ORDER_LITTLE_ENDIAN
+# endif
+#else
+# ifdef __BIG_ENDIAN
+# define LINUX_BYTE_ORDER_BIG_ENDIAN
+# else
+# define LINUX_BYTE_ORDER_LITTLE_ENDIAN
+# endif
+#endif
+
+#ifdef __LP64__
+# define LINUX_FIELD_u32_u64(field) __u64 field
+# define LINUX_FIELD_u32_u64_INIT_ONSTACK(field, v) field = (intptr_t)v
+#else
+# ifdef LINUX_BYTE_ORDER_BIG_ENDIAN
+# define LINUX_FIELD_u32_u64(field) __u32 field ## _padding, field
+# define LINUX_FIELD_u32_u64_INIT_ONSTACK(field, v) \
+ field ## _padding = 0, field = (intptr_t)v
+# else
+# define LINUX_FIELD_u32_u64(field) __u32 field, field ## _padding
+# define LINUX_FIELD_u32_u64_INIT_ONSTACK(field, v) \
+ field = (intptr_t)v, field ## _padding = 0
+# endif
+#endif
+
+#endif /* _UAPI_LINUX_TYPES_32_64_H */
--
2.11.0
^ permalink raw reply related
* [RFC PATCH for 4.18 00/14] Restartable Sequences
From: Mathieu Desnoyers @ 2018-04-30 22:44 UTC (permalink / raw)
To: Peter Zijlstra, Paul E . McKenney, Boqun Feng, Andy Lutomirski,
Dave Watson
Cc: linux-kernel, linux-api, Paul Turner, Andrew Morton, Russell King,
Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Andrew Hunter,
Andi Kleen, Chris Lameter, Ben Maurer, Steven Rostedt,
Josh Triplett, Linus Torvalds, Catalin Marinas, Will Deacon,
Michael Kerrisk, Joel Fernandes, Mathieu Desnoyers
Hi,
Here is an updated RFC round of the Restartable Sequences patchset
based on kernel 4.17-rc3. Based on feedback from Linus, I'm introducing
only the rseq system call, keeping the rest for later.
This already enables speeding up the Facebook jemalloc and arm64 PMC
read from user-space use-cases, as well as speedup of use-cases relying
on getting the current cpu number from user-space. We'll have to wait
until a more complete solution is introduced before the LTTng-UST
tracer can replace its ring buffer atomic instructions with rseq
though. But let's proceed one step at a time.
The main change introduced by the removal of cpu_opv from this series
in terms of library use from user-space is that APIs that previously
took a CPU number as argument now only act on the current CPU.
So for instance, this turns:
int cpu = rseq_per_cpu_lock(lock, target_cpu);
[...]
rseq_per_cpu_unlock(lock, cpu);
into
int cpu = rseq_this_cpu_lock(lock);
[...]
rseq_per_cpu_unlock(lock, cpu);
and:
per_cpu_list_push(list, node, target_cpu);
[...]
per_cpu_list_pop(list, node, target_cpu);
into
this_cpu_list_push(list, node, &cpu); /* cpu is an output parameter. */
[...]
node = this_cpu_list_pop(list, &cpu); /* cpu is an output parameter. */
Eventually integrating cpu_opv or some alternative will allow passing
the cpu number as parameter rather than requiring the algorithm to work
on the current CPU.
The second effect of not having the cpu_opv fallback is that
line and instruction single-stepping with a debugger transforms rseq
critical sections based on retry loops into never-ending loops.
Debuggers need to use the __rseq_table section to skip those critical
sections in order to correctly behave when single-stepping a thread
which uses rseq in a retry loop. However, applications which use an
alternative fallback method rather than retrying on rseq fast-path abort
won't be affected by this kind of single-stepping issue.
Feedback is welcome!
Thanks,
Mathieu
Boqun Feng (2):
powerpc: Add support for restartable sequences
powerpc: Wire up restartable sequences system call
Mathieu Desnoyers (12):
uapi headers: Provide types_32_64.h (v2)
rseq: Introduce restartable sequences system call (v13)
arm: Add restartable sequences support
arm: Wire up restartable sequences system call
x86: Add support for restartable sequences (v2)
x86: Wire up restartable sequence system call
selftests: lib.mk: Introduce OVERRIDE_TARGETS
rseq: selftests: Provide rseq library (v5)
rseq: selftests: Provide basic test
rseq: selftests: Provide basic percpu ops test (v2)
rseq: selftests: Provide parametrized tests (v2)
rseq: selftests: Provide Makefile, scripts, gitignore (v2)
MAINTAINERS | 12 +
arch/Kconfig | 7 +
arch/arm/Kconfig | 1 +
arch/arm/kernel/signal.c | 7 +
arch/arm/tools/syscall.tbl | 1 +
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/systbl.h | 1 +
arch/powerpc/include/asm/unistd.h | 2 +-
arch/powerpc/include/uapi/asm/unistd.h | 1 +
arch/powerpc/kernel/signal.c | 3 +
arch/x86/Kconfig | 1 +
arch/x86/entry/common.c | 3 +
arch/x86/entry/syscalls/syscall_32.tbl | 1 +
arch/x86/entry/syscalls/syscall_64.tbl | 1 +
arch/x86/kernel/signal.c | 6 +
fs/exec.c | 1 +
include/linux/sched.h | 134 +++
include/linux/syscalls.h | 4 +-
include/trace/events/rseq.h | 56 +
include/uapi/linux/rseq.h | 150 +++
include/uapi/linux/types_32_64.h | 67 ++
init/Kconfig | 23 +
kernel/Makefile | 1 +
kernel/fork.c | 2 +
kernel/rseq.c | 366 ++++++
kernel/sched/core.c | 2 +
kernel/sys_ni.c | 3 +
tools/testing/selftests/Makefile | 1 +
tools/testing/selftests/lib.mk | 4 +
tools/testing/selftests/rseq/.gitignore | 6 +
tools/testing/selftests/rseq/Makefile | 29 +
.../testing/selftests/rseq/basic_percpu_ops_test.c | 312 +++++
tools/testing/selftests/rseq/basic_test.c | 55 +
tools/testing/selftests/rseq/param_test.c | 1259 ++++++++++++++++++++
tools/testing/selftests/rseq/rseq-arm.h | 732 ++++++++++++
tools/testing/selftests/rseq/rseq-ppc.h | 688 +++++++++++
tools/testing/selftests/rseq/rseq-skip.h | 82 ++
tools/testing/selftests/rseq/rseq-x86.h | 1149 ++++++++++++++++++
tools/testing/selftests/rseq/rseq.c | 116 ++
tools/testing/selftests/rseq/rseq.h | 164 +++
tools/testing/selftests/rseq/run_param_test.sh | 120 ++
41 files changed, 5572 insertions(+), 2 deletions(-)
create mode 100644 include/trace/events/rseq.h
create mode 100644 include/uapi/linux/rseq.h
create mode 100644 include/uapi/linux/types_32_64.h
create mode 100644 kernel/rseq.c
create mode 100644 tools/testing/selftests/rseq/.gitignore
create mode 100644 tools/testing/selftests/rseq/Makefile
create mode 100644 tools/testing/selftests/rseq/basic_percpu_ops_test.c
create mode 100644 tools/testing/selftests/rseq/basic_test.c
create mode 100644 tools/testing/selftests/rseq/param_test.c
create mode 100644 tools/testing/selftests/rseq/rseq-arm.h
create mode 100644 tools/testing/selftests/rseq/rseq-ppc.h
create mode 100644 tools/testing/selftests/rseq/rseq-skip.h
create mode 100644 tools/testing/selftests/rseq/rseq-x86.h
create mode 100644 tools/testing/selftests/rseq/rseq.c
create mode 100644 tools/testing/selftests/rseq/rseq.h
create mode 100755 tools/testing/selftests/rseq/run_param_test.sh
--
2.11.0
^ permalink raw reply
* Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat
From: Vlastimil Babka @ 2018-04-30 15:30 UTC (permalink / raw)
To: David Rientjes
Cc: Michal Hocko, Roman Gushchin, linux-mm, linux-kernel, linux-api,
kernel-team, Matthew Wilcox, Andrew Morton, Alexander Viro,
Johannes Weiner
In-Reply-To: <alpine.DEB.2.21.1804271139500.152082@chino.kir.corp.google.com>
On 04/27/2018 08:41 PM, David Rientjes wrote:
> On Fri, 27 Apr 2018, Vlastimil Babka wrote:
>
>> It was in the original thread, see e.g.
>> <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz>
>>
>> However it will take some time to get that in mainline, and meanwhile
>> the current implementation does prevent a DOS. So I doubt it can be
>> fully reverted - as a compromise I just didn't want the counter to
>> become ABI. TBH though, other people at LSF/MM didn't seem concerned
>> that /proc/vmstat is an ABI that we can't change (i.e. counters have
>> been presumably removed in the past already).
>>
>
> What prevents this from being a simple atomic_t that gets added to in
> __d_alloc(), subtracted from in __d_free_external_name(), and read in
> si_mem_available() and __vm_enough_memory()?
The counter is already in mainline, so I think it's easier to simply
just stop printing it now than trying to replace its implementation with
one that can cause cache ping pongs.
^ permalink raw reply
* Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat
From: Matthew Wilcox @ 2018-04-27 18:57 UTC (permalink / raw)
To: David Rientjes
Cc: Vlastimil Babka, Michal Hocko, Roman Gushchin, linux-mm,
linux-kernel, linux-api, kernel-team, Andrew Morton,
Alexander Viro, Johannes Weiner
In-Reply-To: <alpine.DEB.2.21.1804271139500.152082@chino.kir.corp.google.com>
On Fri, Apr 27, 2018 at 11:41:31AM -0700, David Rientjes wrote:
> On Fri, 27 Apr 2018, Vlastimil Babka wrote:
>
> > It was in the original thread, see e.g.
> > <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz>
> >
> > However it will take some time to get that in mainline, and meanwhile
> > the current implementation does prevent a DOS. So I doubt it can be
> > fully reverted - as a compromise I just didn't want the counter to
> > become ABI. TBH though, other people at LSF/MM didn't seem concerned
> > that /proc/vmstat is an ABI that we can't change (i.e. counters have
> > been presumably removed in the past already).
> >
>
> What prevents this from being a simple atomic_t that gets added to in
> __d_alloc(), subtracted from in __d_free_external_name(), and read in
> si_mem_available() and __vm_enough_memory()?
I'd think you'd want one atomic_t per NUMA node at least ...
^ permalink raw reply
* Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat
From: David Rientjes @ 2018-04-27 18:41 UTC (permalink / raw)
To: Vlastimil Babka
Cc: Michal Hocko, Roman Gushchin, linux-mm, linux-kernel, linux-api,
kernel-team, Matthew Wilcox, Andrew Morton, Alexander Viro,
Johannes Weiner
In-Reply-To: <99208563-1171-b7e7-a0d7-b47b6c5e2307@suse.cz>
On Fri, 27 Apr 2018, Vlastimil Babka wrote:
> It was in the original thread, see e.g.
> <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz>
>
> However it will take some time to get that in mainline, and meanwhile
> the current implementation does prevent a DOS. So I doubt it can be
> fully reverted - as a compromise I just didn't want the counter to
> become ABI. TBH though, other people at LSF/MM didn't seem concerned
> that /proc/vmstat is an ABI that we can't change (i.e. counters have
> been presumably removed in the past already).
>
What prevents this from being a simple atomic_t that gets added to in
__d_alloc(), subtracted from in __d_free_external_name(), and read in
si_mem_available() and __vm_enough_memory()?
^ permalink raw reply
* Re: [PATCH RFC v5] pidns: introduce syscall translate_pid
From: Michael Kerrisk (man-pages) @ 2018-04-27 12:15 UTC (permalink / raw)
To: Konstantin Khlebnikov, Eric W. Biederman, Nagarathnam Muthusamy
Cc: mtk.manpages, linux-api, linux-kernel, Jann Horn, Serge Hallyn,
Oleg Nesterov, Andy Lutomirski, Prakash Sangappa, Andrew Morton
In-Reply-To: <112c7cac-1982-3a2e-ffc0-878bc5ae4bb6@yandex-team.ru>
On 04/05/2018 09:02 AM, Konstantin Khlebnikov wrote:
> On 05.04.2018 01:29, Eric W. Biederman wrote:
>> Nagarathnam Muthusamy <nagarathnam.muthusamy@oracle.com> writes:
>>
>>> On 04/04/2018 12:11 PM, Konstantin Khlebnikov wrote:
>>>> Each process have different pids, one for each pid namespace it belongs.
>>>> When interaction happens within single pid-ns translation isn't required.
>>>> More complicated scenarios needs special handling.
>>>>
>>>> For example:
>>>> - reading pid-files or logs written inside container with pid namespace
>>>> - attaching with ptrace to tasks from different pid namespace
>>>> - passing pids across pid namespaces in any kind of API
>>>>
>>>> Currently there are several interfaces that could be used here:
>>>>
>>>> Pid namespaces are identified by inode number of /proc/[pid]/ns/pid.
>>
>> Using the inode number in interfaces is not an option. Especially not
>> withou referencing the device number for the filesystem as well.
>
> This is supposed to be single-instance fs,
> not part of proc but referenced but its magic "symlinks".
>
> Device numbers are not mentioned in "man namespaces".
Thanks for the heads-up!
That was a bug in the man-page. ioctl_ns(2) already says the right thing.
Now I patches namespaces(7), as below.
Cheers,
Michael
diff --git a/man7/namespaces.7 b/man7/namespaces.7
index 725ebaff6..3c155de7e 100644
--- a/man7/namespaces.7
+++ b/man7/namespaces.7
@@ -154,11 +154,14 @@ In Linux 3.7 and earlier, these files were visible as hard links.
Since Linux 3.8,
.\" commit bf056bfa80596a5d14b26b17276a56a0dcb080e5
they appear as symbolic links.
-If two processes are in the same namespace, then the inode numbers of their
+If two processes are in the same namespace,
+then the device IDs and inode numbers of their
.IR /proc/[pid]/ns/xxx
symbolic links will be the same; an application can check this using the
+.I stat.st_dev
+and
.I stat.st_ino
-field returned by
+fields returned by
.BR stat (2).
The content of this symbolic link is a string containing
the namespace type and inode number as in the following example:
--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/
^ permalink raw reply related
* Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat
From: Vlastimil Babka @ 2018-04-27 11:06 UTC (permalink / raw)
To: Roman Gushchin
Cc: David Rientjes, Michal Hocko, linux-mm, linux-kernel, linux-api,
kernel-team, Matthew Wilcox, Andrew Morton, Alexander Viro,
Johannes Weiner
In-Reply-To: <20180427105549.GA8127@castle.DHCP.thefacebook.com>
On 04/27/2018 12:55 PM, Roman Gushchin wrote:
> On Fri, Apr 27, 2018 at 11:17:01AM +0200, Vlastimil Babka wrote:
>> On 04/26/2018 11:55 PM, David Rientjes wrote:
>>>
>>> Implementing this counter as a vmstat doesn't make much sense based on how
>>> it's used. Do you have a link to what Vlastimil proposed? I haven't seen
>>> mention of alternative ideas.
>>
>> It was in the original thread, see e.g.
>> <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz>
>>
>> However it will take some time to get that in mainline, and meanwhile
>> the current implementation does prevent a DOS. So I doubt it can be
>> fully reverted - as a compromise I just didn't want the counter to
>> become ABI. TBH though, other people at LSF/MM didn't seem concerned
>> that /proc/vmstat is an ABI that we can't change (i.e. counters have
>> been presumably removed in the past already).
>>
>
> Thank you, Vlastimil!
> That pretty much matches my understanding of the case.
>
> BTW, are you planning to work on supporting reclaimable objects
> by slab allocators?
Yeah, soon!
Vlastimil
> Thanks!
> --
> To unsubscribe from this list: send the line "unsubscribe linux-api" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply
* Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat
From: Roman Gushchin @ 2018-04-27 10:55 UTC (permalink / raw)
To: Vlastimil Babka
Cc: David Rientjes, Michal Hocko, linux-mm, linux-kernel, linux-api,
kernel-team, Matthew Wilcox, Andrew Morton, Alexander Viro,
Johannes Weiner
In-Reply-To: <99208563-1171-b7e7-a0d7-b47b6c5e2307@suse.cz>
On Fri, Apr 27, 2018 at 11:17:01AM +0200, Vlastimil Babka wrote:
> On 04/26/2018 11:55 PM, David Rientjes wrote:
> > On Thu, 26 Apr 2018, Michal Hocko wrote:
> >
> >>> Don't show nr_indirectly_reclaimable in /proc/vmstat,
> >>> because there is no need in exporting this vm counter
> >>> to the userspace, and some changes are expected
> >>> in reclaimable object accounting, which can alter
> >>> this counter.
> >>>
> >>> Signed-off-by: Roman Gushchin <guro@fb.com>
> >>> Cc: Vlastimil Babka <vbabka@suse.cz>
> >>> Cc: Matthew Wilcox <willy@infradead.org>
> >>> Cc: Andrew Morton <akpm@linux-foundation.org>
> >>> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
> >>> Cc: Michal Hocko <mhocko@suse.com>
> >>> Cc: Johannes Weiner <hannes@cmpxchg.org>
> >>
> >> This is quite a hack. I would much rather revert the counter and fixed
> >> it the way Vlastimil has proposed. But if there is a strong opposition
> >> to the revert then this is probably the simples thing to do. Therefore
> >>
> >
> > Implementing this counter as a vmstat doesn't make much sense based on how
> > it's used. Do you have a link to what Vlastimil proposed? I haven't seen
> > mention of alternative ideas.
>
> It was in the original thread, see e.g.
> <08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz>
>
> However it will take some time to get that in mainline, and meanwhile
> the current implementation does prevent a DOS. So I doubt it can be
> fully reverted - as a compromise I just didn't want the counter to
> become ABI. TBH though, other people at LSF/MM didn't seem concerned
> that /proc/vmstat is an ABI that we can't change (i.e. counters have
> been presumably removed in the past already).
>
Thank you, Vlastimil!
That pretty much matches my understanding of the case.
BTW, are you planning to work on supporting reclaimable objects
by slab allocators?
Thanks!
^ permalink raw reply
* Re: [PATCH] mm: don't show nr_indirectly_reclaimable in /proc/vmstat
From: Vlastimil Babka @ 2018-04-27 9:17 UTC (permalink / raw)
To: David Rientjes, Michal Hocko
Cc: Roman Gushchin, linux-mm, linux-kernel, linux-api, kernel-team,
Matthew Wilcox, Andrew Morton, Alexander Viro, Johannes Weiner
In-Reply-To: <alpine.DEB.2.21.1804261453460.238822@chino.kir.corp.google.com>
On 04/26/2018 11:55 PM, David Rientjes wrote:
> On Thu, 26 Apr 2018, Michal Hocko wrote:
>
>>> Don't show nr_indirectly_reclaimable in /proc/vmstat,
>>> because there is no need in exporting this vm counter
>>> to the userspace, and some changes are expected
>>> in reclaimable object accounting, which can alter
>>> this counter.
>>>
>>> Signed-off-by: Roman Gushchin <guro@fb.com>
>>> Cc: Vlastimil Babka <vbabka@suse.cz>
>>> Cc: Matthew Wilcox <willy@infradead.org>
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Alexander Viro <viro@zeniv.linux.org.uk>
>>> Cc: Michal Hocko <mhocko@suse.com>
>>> Cc: Johannes Weiner <hannes@cmpxchg.org>
>>
>> This is quite a hack. I would much rather revert the counter and fixed
>> it the way Vlastimil has proposed. But if there is a strong opposition
>> to the revert then this is probably the simples thing to do. Therefore
>>
>
> Implementing this counter as a vmstat doesn't make much sense based on how
> it's used. Do you have a link to what Vlastimil proposed? I haven't seen
> mention of alternative ideas.
It was in the original thread, see e.g.
<08524819-14ef-81d0-fa90-d7af13c6b9d5@suse.cz>
However it will take some time to get that in mainline, and meanwhile
the current implementation does prevent a DOS. So I doubt it can be
fully reverted - as a compromise I just didn't want the counter to
become ABI. TBH though, other people at LSF/MM didn't seem concerned
that /proc/vmstat is an ABI that we can't change (i.e. counters have
been presumably removed in the past already).
^ permalink raw reply
* [RFC] vfs: skip extra attributes check on removal for symlinks
From: Luis R. Rodriguez @ 2018-04-26 23:46 UTC (permalink / raw)
To: viro, linux-fsdevel, linux-api
Cc: sandeen, darrick.wong, dhowells, tytso, fliu, jack, jeffm,
nborisov, jake.norris, mtk.manpages, linux-xfs, linux-kernel,
Luis R. Rodriguez
Linux filesystems cannot set extra file attributes (stx_attributes as per
statx(2)) on a symbolic link. To set extra file attributes you issue
ioctl(2) with FS_IOC_SETFLAGS, *all* ioctl(2) calls on a symbolic link
yield EBADF.
This is because ioctl(2) tries to obtain struct fd from the symbolic link
file descriptor passed using fdget(), fdget() in turn always returns no
file set when a file descriptor is open with O_PATH. As per symlink(2)
O_PATH and O_NOFOLLOW must *always* be used when you want to get the file
descriptor of a symbolic link, and this holds true for Linux, as such extra
file attributes cannot possibly be set on symbolic links on Linux.
Filesystems repair utilities should be updated to detect this as
corruption and correct this, however, the VFS *does* respect these
extra attributes on symlinks for removal.
Since we cannot set these attributes we should special-case the
immutable/append on delete for symlinks, this would be consistent with
what we *do* allow on Linux for all filesystems.
The userspace utility chattr(1) cannot set these attributes on symlinks
*and* other special files as well:
# chattr -a symlink
chattr: Operation not supported while reading flags on b
The reason for this is different though. Refer to commit 023d111e92195
("chattr.1.in: Document the compression attribute flags E, X, and ...")
merged on e2fsprogs v1.28 since August 2002. This commit prevented
issuing the ioctl() for symlink *and* special files in consideration for
a buggy DRM driver where issuing lsattr on their special files crashed
the system. For details refer to Debian bug 152029 [0].
You can craft your own tool to query the extra file attributes with
the new shiny statx(2) tool, statx(2) will list the attributes if
they were set for instance on a corrupt filesystem. However statx(2)
is only used for *querying* -- not for setting the attributes.
If you implement issuing your own ioctl() for FS_IOC_FSGETXATTR or
FS_IOC_FSSETXATTR on special files (block, char, fifo) it will fail
returning -1 and errno is set to ENOTTY (Inappropriate ioctl for
device). The reason for this is different than for symlinks.
For special files this fails on vfs_ioctl() when the filesystem
f_op callbacks are not set for these special files:
long vfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
int error = -ENOTTY;
if (!filp->f_op->unlocked_ioctl)
goto out;
error = filp->f_op->unlocked_ioctl(filp, cmd, arg);
if (error == -ENOIOCTLCMD)
error = -ENOTTY;
out:
return error;
}
The same applies to PF_LOCAL named sockets. Since this varies by
filesystem for special files, only make a special rule to respect
the immutable and append attribute on symlinks.
[0] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=152029
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
---
As discussed at LSF/MM -- I'd follow up on this low hanging fruit as
the discussion had stalled on linux-xfs on review of the respective
xfs_repair changes. This addresses the general API question, and
as such I think could help establish order in how we split up patches
for those changes.
This requires some other eyeballs, and it also requires a putting it through
xfstests which I can do in the next few days, hence the RFC. But better put it
out for review already. I'd also like feedback from the linux-api folks to
see if this matches their own known / documented expectations.
fs/namei.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index 186bd2464fd5..0f9069468cfb 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2719,6 +2719,14 @@ int __check_sticky(struct inode *dir, struct inode *inode)
}
EXPORT_SYMBOL(__check_sticky);
+/* Process extra file attributes only when they make sense */
+static bool may_delete_stx_attributes(struct inode *inode)
+{
+ if (!S_ISLNK(inode->i_mode) && (IS_APPEND(inode) || IS_IMMUTABLE(inode)))
+ return false;
+ return true;
+}
+
/*
* Check whether we can remove a link victim from directory dir, check
* whether the type of victim is right.
@@ -2757,8 +2765,8 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
if (IS_APPEND(dir))
return -EPERM;
- if (check_sticky(dir, inode) || IS_APPEND(inode) ||
- IS_IMMUTABLE(inode) || IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode))
+ if (check_sticky(dir, inode) || !may_delete_stx_attributes(inode) ||
+ IS_SWAPFILE(inode) || HAS_UNMAPPED_ID(inode))
return -EPERM;
if (isdir) {
if (!d_is_dir(victim))
--
2.17.0
^ permalink raw reply related
* Re: [RFC PATCH ghak32 V2 01/13] audit: add container id
From: Paul Moore @ 2018-04-26 22:47 UTC (permalink / raw)
To: Richard Guy Briggs
Cc: cgroups, containers, linux-api, Linux-Audit Mailing List,
linux-fsdevel, LKML, netdev, ebiederm, luto, jlayton, carlos,
dhowells, viro, simo, Eric Paris, serge
In-Reply-To: <20180425004031.zutsno6hvmpq3crd@madcap2.tricolour.ca>
On Tue, Apr 24, 2018 at 8:40 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
> On 2018-04-24 15:01, Paul Moore wrote:
>> On Mon, Apr 23, 2018 at 10:02 PM, Richard Guy Briggs <rgb@redhat.com> wrote:
>> > On 2018-04-23 19:15, Paul Moore wrote:
>> >> On Sat, Apr 21, 2018 at 10:34 AM, Richard Guy Briggs <rgb@redhat.com> wrote:
>> >> > On 2018-04-18 19:47, Paul Moore wrote:
>> >> >> On Fri, Mar 16, 2018 at 5:00 AM, Richard Guy Briggs <rgb@redhat.com> wrote:
>> >> >> > Implement the proc fs write to set the audit container ID of a process,
>> >> >> > emitting an AUDIT_CONTAINER record to document the event.
>> >> >> >
>> >> >> > This is a write from the container orchestrator task to a proc entry of
>> >> >> > the form /proc/PID/containerid where PID is the process ID of the newly
>> >> >> > created task that is to become the first task in a container, or an
>> >> >> > additional task added to a container.
>> >> >> >
>> >> >> > The write expects up to a u64 value (unset: 18446744073709551615).
>> >> >> >
>> >> >> > This will produce a record such as this:
>> >> >> > type=CONTAINER msg=audit(1519903238.968:261): op=set pid=596 uid=0 subj=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023 auid=0 tty=pts0 ses=1 opid=596 old-contid=18446744073709551615 contid=123455 res=0
>> >> >> >
>> >> >> > The "op" field indicates an initial set. The "pid" to "ses" fields are
>> >> >> > the orchestrator while the "opid" field is the object's PID, the process
>> >> >> > being "contained". Old and new container ID values are given in the
>> >> >> > "contid" fields, while res indicates its success.
>> >> >> >
>> >> >> > It is not permitted to self-set, unset or re-set the container ID. A
>> >> >> > child inherits its parent's container ID, but then can be set only once
>> >> >> > after.
>> >> >> >
>> >> >> > See: https://github.com/linux-audit/audit-kernel/issues/32
>> >> >> >
>> >> >> > Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
>> >> >> > ---
>> >> >> > fs/proc/base.c | 37 ++++++++++++++++++++
>> >> >> > include/linux/audit.h | 16 +++++++++
>> >> >> > include/linux/init_task.h | 4 ++-
>> >> >> > include/linux/sched.h | 1 +
>> >> >> > include/uapi/linux/audit.h | 2 ++
>> >> >> > kernel/auditsc.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++
>> >> >> > 6 files changed, 143 insertions(+), 1 deletion(-)
>>
>> ...
>>
>> >> >> > /* audit_rule_data supports filter rules with both integer and string
>> >> >> > * fields. It corresponds with AUDIT_ADD_RULE, AUDIT_DEL_RULE and
>> >> >> > diff --git a/kernel/auditsc.c b/kernel/auditsc.c
>> >> >> > index 4e0a4ac..29c8482 100644
>> >> >> > --- a/kernel/auditsc.c
>> >> >> > +++ b/kernel/auditsc.c
>> >> >> > @@ -2073,6 +2073,90 @@ int audit_set_loginuid(kuid_t loginuid)
>> >> >> > return rc;
>> >> >> > }
>> >> >> >
>> >> >> > +static int audit_set_containerid_perm(struct task_struct *task, u64 containerid)
>> >> >> > +{
>> >> >> > + struct task_struct *parent;
>> >> >> > + u64 pcontainerid, ccontainerid;
>> >> >> > +
>> >> >> > + /* Don't allow to set our own containerid */
>> >> >> > + if (current == task)
>> >> >> > + return -EPERM;
>> >> >>
>> >> >> Why not? Is there some obvious security concern that I missing?
>> >> >
>> >> > We then lose the distinction in the AUDIT_CONTAINER record between the
>> >> > initiating PID and the target PID. This was outlined in the proposal.
>> >>
>> >> I just went back and reread the v3 proposal and I still don't see a
>> >> good explanation of this. Why is this bad? What's the security
>> >> concern?
>> >
>> > I don't remember, specifically. Maybe this has been addressed by the
>> > check for children/threads or identical parent container ID. So, I'm
>> > reluctantly willing to remove that check for now.
>>
>> Okay. For the record, if someone can explain to me why this
>> restriction saves us from some terrible situation I'm all for leaving
>> it. I'm just opposed to restrictions without solid reasoning behind
>> them.
>>
>> >> > Having said that, I'm still not sure we have protected sufficiently from
>> >> > a child turning around and setting it's parent's as yet unset or
>> >> > inherited audit container ID.
>> >>
>> >> Yes, I believe we only want to let a task set the audit container for
>> >> it's children (or itself/threads if we decide to allow that, see
>> >> above). There *has* to be a function to check to see if a task if a
>> >> child of a given task ... right? ... although this is likely to be a
>> >> pointer traversal and locking nightmare ... hmmm.
>> >
>> > Isn't that just (struct task_struct)parent == (struct
>> > task_struct)child->parent (or ->real_parent)?
>> >
>> > And now that I say that, it is covered by the following patch's child
>> > check, so as long as we keep that, we should be fine.
>>
>> I was thinking of checking not just current's immediate children, but
>> any of it's descendants as I believe that is what we want to limit,
>> yes? I just worry that it isn't really practical to perform that
>> check.
>
> The child check I'm talking about prevents setting a task's audit
> container ID if it *has* any children or threads, so if it has children
> it is automatically disqualified and its grandchildren are irrelevant.
>
>> >> >> I ask because I suppose it might be possible for some container
>> >> >> runtime to do a fork, setup some of the environment and them exec the
>> >> >> container (before you answer the obvious "namespaces!" please remember
>> >> >> we're not trying to define containers).
>> >> >
>> >> > I don't think namespaces have any bearing on this concern since none are
>> >> > required.
>> >> >
>> >> >> > + /* Don't allow the containerid to be unset */
>> >> >> > + if (!cid_valid(containerid))
>> >> >> > + return -EINVAL;
>> >> >> > + /* if we don't have caps, reject */
>> >> >> > + if (!capable(CAP_AUDIT_CONTROL))
>> >> >> > + return -EPERM;
>> >> >> > + /* if containerid is unset, allow */
>> >> >> > + if (!audit_containerid_set(task))
>> >> >> > + return 0;
>> >> >> > + /* it is already set, and not inherited from the parent, reject */
>> >> >> > + ccontainerid = audit_get_containerid(task);
>> >> >> > + rcu_read_lock();
>> >> >> > + parent = rcu_dereference(task->real_parent);
>> >> >> > + rcu_read_unlock();
>> >> >> > + task_lock(parent);
>> >> >> > + pcontainerid = audit_get_containerid(parent);
>> >> >> > + task_unlock(parent);
>> >> >> > + if (ccontainerid != pcontainerid)
>> >> >> > + return -EPERM;
>> >> >> > + return 0;
>>
>> I'm looking at the parent checks again and I wonder if the logic above
>> is what we really want. Maybe it is, but I'm not sure.
>>
>> Things I'm wondering about:
>>
>> * "ccontainerid" and "containerid" are too close in name, I kept
>> confusing myself when looking at this code. Please change one. Bonus
>> points if it is shorter.
>
> Would c_containerid and p_containerid be ok? child_cid and parent_cid?
Either would be an improvement over ccontainerid/containerid. I would
give a slight node to child_cid/parent_cid just for length reasons.
> I'd really like it to have the same root as the parameter handed in so
> teh code is easier to follow. It would be nice to have that across
> caller to local, but that's challenging.
That's fine, but you have to admit that ccontainerid/containerid is
awkward and not easy to quickly differentiate :)
> I've been tempted to use contid or even cid everywhere instead of
> containerid. Perhaps the longer name doesn't bother me because I
> like its uniqueness and I learned touch-typing in grade 9 and I like
> 100+ character wide terminals? ;-)
I would definitely appreciate contid/cid or similar, but I don't care
too much either way. As far as terminal width is concerned, please
make sure your code fits in 80 char terminals.
>> * What if the orchestrator wants to move the task to a new container?
>> Right now it looks like you can only do that once, then then the
>> task's audit container ID will no longer be the same as real_parent
>
> A task's audit container ID can be unset or inherited, and then set
> only once. After that, if you want it moved to a new container you
> can't and your only option is to spawn another peer to that task or a
> child of it and set that new task's audit container ID.
Okay. We've had some many discussions about this both on and off list
that I lose track on where we stand for certain things. I think
preventing task movement is fine for the initial effort so long as we
don't prevent adding it in the future; I don't see anything (other
than the permission checks under discussion, which is fine) preventing
this.
> Currently, the method of detecting if its audit container ID has been
> set (rather than inherited) was to check its parent's audit container
> ID.
Yeah ... those are two different things. I've been wondering if we
should introduce a set/inherited flag as simply checking the parent
task's audit container ID isn't quite the same; although it may be
"close enough" that it doesn't matter in practice. However, I'm
beginning to think this parent/child relationship isn't really
important beyond the inheritance issue ... more on this below.
> The only reason to change this might be if the audit container ID
> were not inheritable, but then we lose the accountability of a task
> spawning another process and being able to leave its child's audit
> container ID unset and unaccountable to any existing container. I think
> the relationship to the parent is crucial, and if something wants to
> change audit container ID it can, by spawning childrent and leaving a
> trail of container IDs in its parent processes. (So what if a parent
> dies?)
The audit container ID *must* be inherited, I don't really think
anyone is questioning that. What I'm wondering about is what we
accomplish by comparing the child's and parent's audit container ID?
I've thought about this a bit more and I think we are making this way
too complicated right now. We basically have three rules for the
audit container ID which we need to follow:
1. Children inherit their parent's audit container ID; this includes
the magic "unset" audit container ID.
2. You can't change the audit container ID once set.
3. In order to set the audit container ID of a process you must have
CAP_AUDIT_CONTROL.
With that in mind, I think the permission checks would be something like this:
[SIDE NOTE: Audit Container ID in acronym form works out to "acid" ;) ]
int perm(task, acid)
{
if (!task || !valid(acid))
return -EINVAL;
if (!capable(CAP_AUDIT_CONTROL))
return -EPERM;
if (task->acid != UNSET)
return -EPERM;
return 0;
}
>> ... or does the orchestrator change that? *Can* the orchestrator
>> change real_parent (I suspect the answer is "no")?
>
> I don't think the orchestrator is able to change real_parent.
I didn't think so either, but I didn't do an exhaustive check.
> I've forgotten why there is a ->parent and ->real_parent and how they can
> change. One is for the wait signal. I don't remember the purpose of
> the other.
I know ptrace makes use of real_parent when re-parenting the process
being ptrace'd.
> If the parent dies before the child, the child will be re-parented on
> its grandparent if the parent doesn't hang around zombified, if I
> understand correctly. If anything, a parent dying would likely further
> restrict the ability to set a task's audit container ID because a parent
> with an identical ID could vanish.
All the more reason to go with the simplified approach above. I think
the parent/child relationship is a bit of a distraction and a
complexity that isn't important (except for the inheritance of
course).
>> * I think the key is the relationship between current and task, not
>> between task and task->real_parent. I believe what we really care
>> about is that task is a descendant of current. We might also want to
>> allow current to change the audit container ID if it holds
>> CAP_AUDIT_CONTROL, regardless of it's relationship with task.
>
> Currently, a process with CAP_AUDIT_CONTROL can set the audit container
> ID of any task that hasn't got children or threads, isn't itself, and
> its audit container ID is inherited or unset. This was to try to
> prevent games with parents and children scratching each other's backs.
>
> I would feel more comfortable if only descendants were settable, so
> adding that restriction sounds like a good idea to me other than the
> tree-climbing excercise and overhead involved.
>
>> >> >> > +static void audit_log_set_containerid(struct task_struct *task, u64 oldcontainerid,
>> >> >> > + u64 containerid, int rc)
>> >> >> > +{
>> >> >> > + struct audit_buffer *ab;
>> >> >> > + uid_t uid;
>> >> >> > + struct tty_struct *tty;
>> >> >> > +
>> >> >> > + if (!audit_enabled)
>> >> >> > + return;
>> >> >> > +
>> >> >> > + ab = audit_log_start(NULL, GFP_KERNEL, AUDIT_CONTAINER);
>> >> >> > + if (!ab)
>> >> >> > + return;
>> >> >> > +
>> >> >> > + uid = from_kuid(&init_user_ns, task_uid(current));
>> >> >> > + tty = audit_get_tty(current);
>> >> >> > +
>> >> >> > + audit_log_format(ab, "op=set pid=%d uid=%u", task_tgid_nr(current), uid);
>> >> >> > + audit_log_task_context(ab);
>> >> >> > + audit_log_format(ab, " auid=%u tty=%s ses=%u opid=%d old-contid=%llu contid=%llu res=%d",
>> >> >> > + from_kuid(&init_user_ns, audit_get_loginuid(current)),
>> >> >> > + tty ? tty_name(tty) : "(none)", audit_get_sessionid(current),
>> >> >> > + task_tgid_nr(task), oldcontainerid, containerid, !rc);
>> >> >> > +
>> >> >> > + audit_put_tty(tty);
>> >> >> > + audit_log_end(ab);
>> >> >> > +}
>> >> >> > +
>> >> >> > +/**
>> >> >> > + * audit_set_containerid - set current task's audit_context containerid
>> >> >> > + * @containerid: containerid value
>> >> >> > + *
>> >> >> > + * Returns 0 on success, -EPERM on permission failure.
>> >> >> > + *
>> >> >> > + * Called (set) from fs/proc/base.c::proc_containerid_write().
>> >> >> > + */
>> >> >> > +int audit_set_containerid(struct task_struct *task, u64 containerid)
>> >> >> > +{
>> >> >> > + u64 oldcontainerid;
>> >> >> > + int rc;
>> >> >> > +
>> >> >> > + oldcontainerid = audit_get_containerid(task);
>> >> >> > +
>> >> >> > + rc = audit_set_containerid_perm(task, containerid);
>> >> >> > + if (!rc) {
>> >> >> > + task_lock(task);
>> >> >> > + task->containerid = containerid;
>> >> >> > + task_unlock(task);
>> >> >> > + }
>> >> >> > +
>> >> >> > + audit_log_set_containerid(task, oldcontainerid, containerid, rc);
>> >> >> > + return rc;
>> >> >>
>> >> >> Why are audit_set_containerid_perm() and audit_log_containerid()
>> >> >> separate functions?
>> >> >
>> >> > (I assume you mean audit_log_set_containerid()?)
>> >>
>> >> Yep. My fingers got tired typing in that function name and decided a
>> >> shortcut was necessary.
>> >>
>> >> > It seemed clearer that all the permission checking was in one function
>> >> > and its return code could be used to report the outcome when logging the
>> >> > (attempted) action. This is the same structure as audit_set_loginuid()
>> >> > and it made sense.
>> >>
>> >> When possible I really like it when the permission checks are in the
>> >> same function as the code which does the work; it's less likely to get
>> >> abused that way (you have to willfully bypass the access checks). The
>> >> exceptions might be if you wanted to reuse the access control code, or
>> >> insert a modular access mechanism (e.g. LSMs).
>> >
>> > I don't follow how it could be abused. The return code from the perm
>> > check gates setting the value and is used in the success field in the
>> > log.
>>
>> If the permission checks are in the same function body as the code
>> which does the work you have to either split the function, or rewrite
>> it, if you want to bypass the permission checks. It may be more of a
>> style issue than an actual safety issue, but the comments about
>> single-use functions in the same scope is the tie breaker.
>
> Perhaps I'm just being quite dense, but I just don't follow what the
> problem is and how you suggest fixing it. A bunch of gotos to a label
> such as "out:" to log the refused action? That seems messy and
> unstructured.
Fold audit_set_containerid_perm() and audit_log_set_containerid() into
their only caller, audit_set_containerid().
--
paul moore
www.paul-moore.com
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