[PATCH v3 00/10] posix_clocks: Prepare syscalls for 64 bit time_t conversion

[PATCH v3 00/10] posix_clocks: Prepare syscalls for 64 bit time_t conversion

[Deepa Dinamani]

The series is a preparation series for individual architectures
to use 64 bit time_t syscalls in compat and 32 bit emulation modes.

This is a follow up to the series Arnd Bergmann posted:
https://sourceware.org/ml/libc-alpha/2015-05/msg00070.html [1]

Big picture is as per the lwn article:
https://lwn.net/Articles/643234/ [2]

The series is directed at converting posix clock syscalls:
clock_gettime, clock_settime, clock_getres and clock_nanosleep
to use a new data structure __kernel_timespec at syscall boundaries.
__kernel_timespec maintains 64 bit time_t across all execution modes.

vdso will be handled as part of each architecture when they enable
support for 64 bit time_t.

The compat syscalls are repurposed to provide backward compatibility
by using them as native syscalls as well for 32 bit architectures.
They will continue to use timespec at syscall boundaries.

CONFIG_64_BIT_TIME controls whether the syscalls use __kernel_timespec
or timespec at syscall boundaries.

The series does the following:
1. Enable compat syscalls on 32 bit architectures.
2. Add a new __kernel_timespec type to be used as the data structure
   for all the new syscalls.
3. Add new config CONFIG_64BIT_TIME(intead of the CONFIG_COMPAT_TIME in
   [1] and [2] to switch to new definition of __kernel_timespec. It is
   the same as struct timespec otherwise.
4. Add new CONFIG_32BIT_TIME to conditionally compile compat syscalls.

* Changes since v2:
 * Dropped the ARCH_HAS_64BIT_TIME config.
 * Fixed zeroing out of higher order bits of tv_nsec for real.
 * Addressed minor review comments from v1.
* Changes since v1:
 * Introduce CONFIG_32BIT_TIME
 * Fixed zeroing out of higher order bits of tv_nsec
 * Included Arnd's changes to fix up use of compat headers

I decided against using LEGACY_TIME_SYSCALLS to conditionally compile
legacy time syscalls such as sys_nanosleep because this will need to
enclose compat_sys_nanosleep as well. So, defining it as 

config LEGACY_TIME_SYSCALLS
     def_bool 64BIT || !64BIT_TIME

will not include compat_sys_nanosleep. We will instead need a new config to
exclusively mark legacy syscalls.

Deepa Dinamani (10):
  compat: Make compat helpers independent of CONFIG_COMPAT
  include: Move compat_timespec/ timeval to compat_time.h
  compat: enable compat_get/put_timespec64 always
  arch: introduce CONFIG_64BIT_TIME
  arch: Introduce CONFIG_COMPAT_32BIT_TIME
  posix-clocks: Make compat syscalls depend on CONFIG_COMPAT_32BIT_TIME
  include: Add new y2038 safe __kernel_timespec
  fix get_timespec64() for y2038 safe compat interfaces
  change time types to new y2038 safe __kernel_* types
  nanosleep: change time types to safe __kernel_* types

 arch/Kconfig                           | 15 +++++++++
 arch/arm64/include/asm/compat.h        | 11 -------
 arch/arm64/include/asm/stat.h          |  1 +
 arch/arm64/kernel/hw_breakpoint.c      |  1 -
 arch/arm64/kernel/perf_regs.c          |  2 +-
 arch/arm64/kernel/process.c            |  1 -
 arch/mips/include/asm/compat.h         | 11 -------
 arch/mips/kernel/signal32.c            |  2 +-
 arch/parisc/include/asm/compat.h       | 11 -------
 arch/powerpc/include/asm/compat.h      | 11 -------
 arch/powerpc/kernel/asm-offsets.c      |  2 +-
 arch/powerpc/oprofile/backtrace.c      |  2 +-
 arch/s390/hypfs/hypfs_sprp.c           |  1 -
 arch/s390/include/asm/compat.h         | 11 -------
 arch/s390/include/asm/elf.h            |  3 +-
 arch/s390/kvm/priv.c                   |  1 -
 arch/s390/pci/pci_clp.c                |  1 -
 arch/sparc/include/asm/compat.h        | 11 -------
 arch/tile/include/asm/compat.h         | 11 -------
 arch/x86/events/core.c                 |  2 +-
 arch/x86/include/asm/compat.h          | 11 -------
 arch/x86/include/asm/ftrace.h          |  2 +-
 arch/x86/include/asm/sys_ia32.h        |  2 +-
 arch/x86/kernel/sys_x86_64.c           |  2 +-
 drivers/s390/block/dasd_ioctl.c        |  1 -
 drivers/s390/char/fs3270.c             |  1 -
 drivers/s390/char/sclp_ctl.c           |  1 -
 drivers/s390/char/vmcp.c               |  1 -
 drivers/s390/cio/chsc_sch.c            |  1 -
 drivers/s390/net/qeth_core_main.c      |  2 +-
 include/linux/compat.h                 | 11 ++++---
 include/linux/compat_time.h            | 23 ++++++++++++++
 include/linux/restart_block.h          |  7 ++--
 include/linux/syscalls.h               | 12 +++----
 include/linux/time.h                   |  4 +--
 include/linux/time64.h                 | 10 +++++-
 include/uapi/asm-generic/posix_types.h |  1 +
 include/uapi/linux/time.h              |  7 ++++
 kernel/compat.c                        | 52 +++++-------------------------
 kernel/time/hrtimer.c                  | 10 ++++--
 kernel/time/posix-stubs.c              | 12 ++++---
 kernel/time/posix-timers.c             | 24 ++++++++++----
 kernel/time/time.c                     | 58 +++++++++++++++++++++++++++++++---
 43 files changed, 176 insertions(+), 190 deletions(-)
 create mode 100644 include/linux/compat_time.h


base-commit: 8418f88764046d0e8ca6a3c04a69a0e57189aa1e
-- 
2.14.1

Cc: acme@kernel.org
Cc: benh@kernel.crashing.org
Cc: borntraeger@de.ibm.com
Cc: catalin.marinas@arm.com
Cc: cmetcalf@mellanox.com
Cc: cohuck@redhat.com
Cc: davem@davemloft.net
Cc: deller@gmx.de
Cc: devel@driverdev.osuosl.org
Cc: gerald.schaefer@de.ibm.com
Cc: gregkh@linuxfoundation.org
Cc: heiko.carstens@de.ibm.com
Cc: hoeppner@linux.vnet.ibm.com
Cc: hpa@zytor.com
Cc: jejb@parisc-linux.org
Cc: jwi@linux.vnet.ibm.com
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-parisc@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-s390@vger.kernel.org
Cc: mark.rutland@arm.com
Cc: mingo@redhat.com
Cc: mpe@ellerman.id.au
Cc: oberpar@linux.vnet.ibm.com
Cc: oprofile-list@lists.sf.net
Cc: paulus@samba.org
Cc: peterz@infradead.org
Cc: ralf@linux-mips.org
Cc: rostedt@goodmis.org
Cc: rric@kernel.org
Cc: schwidefsky@de.ibm.com
Cc: sebott@linux.vnet.ibm.com
Cc: sparclinux@vger.kernel.org
Cc: sth@linux.vnet.ibm.com
Cc: ubraun@linux.vnet.ibm.com
Cc: will.deacon@arm.com
Cc: x86@kernel.org

[PATCH v3 09/10] change time types to new y2038 safe __kernel_* types

[Deepa Dinamani]

Change over clock_settime, clock_gettime and clock_getres
syscalls to use __kernel_timespec times. This will enable
changing over of these syscalls to use new y2038 safe syscalls
when the architectures define the CONFIG_64BIT_TIME.

Cc: linux-api@vger.kernel.org
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
---
 include/linux/syscalls.h   | 6 +++---
 kernel/time/posix-stubs.c  | 6 +++---
 kernel/time/posix-timers.c | 6 +++---
 3 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index a78186d826d7..7ac1bb9ea7da 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -309,13 +309,13 @@ asmlinkage long sys_timer_settime(timer_t timer_id, int flags,
 				struct itimerspec __user *old_setting);
 asmlinkage long sys_timer_delete(timer_t timer_id);
 asmlinkage long sys_clock_settime(clockid_t which_clock,
-				const struct timespec __user *tp);
+				const struct __kernel_timespec __user *tp);
 asmlinkage long sys_clock_gettime(clockid_t which_clock,
-				struct timespec __user *tp);
+				struct __kernel_timespec __user *tp);
 asmlinkage long sys_clock_adjtime(clockid_t which_clock,
 				struct timex __user *tx);
 asmlinkage long sys_clock_getres(clockid_t which_clock,
-				struct timespec __user *tp);
+				struct __kernel_timespec __user *tp);
 asmlinkage long sys_clock_nanosleep(clockid_t which_clock, int flags,
 				const struct timespec __user *rqtp,
 				struct timespec __user *rmtp);
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 0645cfa93609..28c22f54d0f2 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -49,7 +49,7 @@ SYS_NI(alarm);
  */
 
 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
-		const struct timespec __user *, tp)
+		const struct __kernel_timespec __user *, tp)
 {
 	struct timespec64 new_tp;
 
@@ -80,7 +80,7 @@ int do_clock_gettime(clockid_t which_clock, struct timespec64 *tp)
 	return 0;
 }
 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
-		struct timespec __user *, tp)
+		struct __kernel_timespec __user *, tp)
 {
 	int ret;
 	struct timespec64 kernel_tp;
@@ -94,7 +94,7 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
 	return 0;
 }
 
-SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp)
+SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct __kernel_timespec __user *, tp)
 {
 	struct timespec64 rtn_tp = {
 		.tv_sec = 0,
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index 673525f98ecf..da17eb61edda 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1039,7 +1039,7 @@ void exit_itimers(struct signal_struct *sig)
 }
 
 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
-		const struct timespec __user *, tp)
+		const struct __kernel_timespec __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 new_tp;
@@ -1054,7 +1054,7 @@ SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
 }
 
 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
-		struct timespec __user *,tp)
+		struct __kernel_timespec __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 kernel_tp;
@@ -1095,7 +1095,7 @@ SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock,
 }
 
 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock,
-		struct timespec __user *, tp)
+		struct __kernel_timespec __user *, tp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 rtn_tp;
-- 
2.14.1

[PATCH v3 10/10] nanosleep: change time types to safe __kernel_* types

[Deepa Dinamani]

Change over clock_nanosleep syscalls to use y2038 safe
__kernel_timespec times. This will enable changing over
of these syscalls to use new y2038 safe syscalls when
the architectures define the CONFIG_64BIT_TIME.

Note that nanosleep syscall is deprecated and does not have a
plan for making it y2038 safe. But, the syscall should work as
before on 64 bit machines and on 32 bit machines, the syscall
works correctly until y2038 as before using the existing compat
syscall version. There is no new syscall for supporting 64 bit
time_t on 32 bit architectures.

Cc: linux-api@vger.kernel.org
Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com>
---
 include/linux/restart_block.h | 7 ++-----
 include/linux/syscalls.h      | 6 +++---
 kernel/time/hrtimer.c         | 8 ++++++--
 kernel/time/posix-stubs.c     | 4 ++--
 kernel/time/posix-timers.c    | 4 ++--
 5 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/include/linux/restart_block.h b/include/linux/restart_block.h
index bcfdb918cd81..5d83d0c1d06c 100644
--- a/include/linux/restart_block.h
+++ b/include/linux/restart_block.h
@@ -7,6 +7,7 @@
 
 #include <linux/compiler.h>
 #include <linux/types.h>
+#include <linux/time64.h>
 
 struct timespec;
 struct compat_timespec;
@@ -15,9 +16,7 @@ struct pollfd;
 enum timespec_type {
 	TT_NONE		= 0,
 	TT_NATIVE	= 1,
-#ifdef CONFIG_COMPAT
 	TT_COMPAT	= 2,
-#endif
 };
 
 /*
@@ -40,10 +39,8 @@ struct restart_block {
 			clockid_t clockid;
 			enum timespec_type type;
 			union {
-				struct timespec __user *rmtp;
-#ifdef CONFIG_COMPAT
+				struct __kernel_timespec __user *rmtp;
 				struct compat_timespec __user *compat_rmtp;
-#endif
 			};
 			u64 expires;
 		} nanosleep;
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index 7ac1bb9ea7da..4df16a70b0d7 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -254,7 +254,7 @@ asmlinkage long sys_adjtimex(struct timex __user *txc_p);
 asmlinkage long sys_times(struct tms __user *tbuf);
 
 asmlinkage long sys_gettid(void);
-asmlinkage long sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp);
+asmlinkage long sys_nanosleep(struct __kernel_timespec __user *rqtp, struct __kernel_timespec __user *rmtp);
 asmlinkage long sys_alarm(unsigned int seconds);
 asmlinkage long sys_getpid(void);
 asmlinkage long sys_getppid(void);
@@ -317,8 +317,8 @@ asmlinkage long sys_clock_adjtime(clockid_t which_clock,
 asmlinkage long sys_clock_getres(clockid_t which_clock,
 				struct __kernel_timespec __user *tp);
 asmlinkage long sys_clock_nanosleep(clockid_t which_clock, int flags,
-				const struct timespec __user *rqtp,
-				struct timespec __user *rmtp);
+				const struct __kernel_timespec __user *rqtp,
+				struct __kernel_timespec __user *rmtp);
 
 asmlinkage long sys_nice(int increment);
 asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 65cc7272d954..ee636646cc07 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1540,8 +1540,10 @@ long hrtimer_nanosleep(const struct timespec64 *rqtp,
 	return ret;
 }
 
-SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
-		struct timespec __user *, rmtp)
+#if !defined(CONFIG_64BIT_TIME) || defined(CONFIG_64BIT)
+
+SYSCALL_DEFINE2(nanosleep, struct __kernel_timespec __user *, rqtp,
+		struct __kernel_timespec __user *, rmtp)
 {
 	struct timespec64 tu;
 
@@ -1556,6 +1558,8 @@ SYSCALL_DEFINE2(nanosleep, struct timespec __user *, rqtp,
 	return hrtimer_nanosleep(&tu, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 }
 
+#endif
+
 #ifdef CONFIG_COMPAT_32BIT_TIME
 
 COMPAT_SYSCALL_DEFINE2(nanosleep, struct compat_timespec __user *, rqtp,
diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 28c22f54d0f2..f7e7a05e651d 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -114,8 +114,8 @@ SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct __kernel_time
 }
 
 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
-		const struct timespec __user *, rqtp,
-		struct timespec __user *, rmtp)
+		const struct __kernel_timespec __user *, rqtp,
+		struct __kernel_timespec __user *, rmtp)
 {
 	struct timespec64 t;
 
diff --git a/kernel/time/posix-timers.c b/kernel/time/posix-timers.c
index da17eb61edda..31ce3482884d 100644
--- a/kernel/time/posix-timers.c
+++ b/kernel/time/posix-timers.c
@@ -1210,8 +1210,8 @@ static int common_nsleep(const clockid_t which_clock, int flags,
 }
 
 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
-		const struct timespec __user *, rqtp,
-		struct timespec __user *, rmtp)
+		const struct __kernel_timespec __user *, rqtp,
+		struct __kernel_timespec __user *, rmtp)
 {
 	const struct k_clock *kc = clockid_to_kclock(which_clock);
 	struct timespec64 t;
-- 
2.14.1

Re: [PATCH v3 00/10] posix_clocks: Prepare syscalls for 64 bit time_t conversion

[Arnd Bergmann]

On Tue, Jan 16, 2018 at 3:18 AM, Deepa Dinamani <deepa.kernel-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> The series is a preparation series for individual architectures
> to use 64 bit time_t syscalls in compat and 32 bit emulation modes.
>
> This is a follow up to the series Arnd Bergmann posted:
> https://sourceware.org/ml/libc-alpha/2015-05/msg00070.html [1]
>
> Big picture is as per the lwn article:
> https://lwn.net/Articles/643234/ [2]
>
> The series is directed at converting posix clock syscalls:
> clock_gettime, clock_settime, clock_getres and clock_nanosleep
> to use a new data structure __kernel_timespec at syscall boundaries.
> __kernel_timespec maintains 64 bit time_t across all execution modes.
>
> vdso will be handled as part of each architecture when they enable
> support for 64 bit time_t.
>
> The compat syscalls are repurposed to provide backward compatibility
> by using them as native syscalls as well for 32 bit architectures.
> They will continue to use timespec at syscall boundaries.
>
> CONFIG_64_BIT_TIME controls whether the syscalls use __kernel_timespec
> or timespec at syscall boundaries.
>
> The series does the following:
> 1. Enable compat syscalls on 32 bit architectures.
> 2. Add a new __kernel_timespec type to be used as the data structure
>    for all the new syscalls.
> 3. Add new config CONFIG_64BIT_TIME(intead of the CONFIG_COMPAT_TIME in
>    [1] and [2] to switch to new definition of __kernel_timespec. It is
>    the same as struct timespec otherwise.
> 4. Add new CONFIG_32BIT_TIME to conditionally compile compat syscalls.

This looks all good to me. I think we should have this included in linux-next as
soon as possible, but this probably means after -rc1 at the current point, since
it's a bit late for 4.16.

I'll pick up the series into my randconfig build tree again to find
possible build
time regressions. Otherwise the way I'd stage it out is to put it into my y2038
branch after -rc1 and then send a pull request to Thomas for the tip tree
a week later. It seems unlikely that any major problems come up, so we could
plan to address additional requests for changes by adding commits on top
once it's in linux-next.

       Arnd