[PATCH v4 0/7] selftests/x86: fix build errors and warnings found via clang

[PATCH v4 0/7] selftests/x86: fix build errors and warnings found via clang

[John Hubbard]

Changes since v3:

1) Rebased onto Linux 6.10-rc6+.

2) Added Muhammad's acks for the series.

Cover letter for v3:

Hi,

Dave Hansen, Muhammad Usama Anjum, here is the combined series that we
discussed yesterday [1].

As I mentioned then, this is a bit intrusive--but no more than
necessary, IMHO. Specifically, it moves some clang-un-inlineable things
out to "pure" assembly code files.

I've tested this by building with clang, then running each binary on my
x86_64 test system with today's 6.10-rc1, and comparing the console and
dmesg output to a gcc-based build without these patches applied. Aside
from timestamps and virtual addresses, it looks identical.

Earlier cover letter:

Just a bunch of build and warnings fixes that show up when building with
clang. Some of these depend on each other, so I'm sending them as a
series.

Changes since v2:

1) Dropped my test_FISTTP.c patch, and picked up Muhammad's fix instead,
   seeing as how that was posted first.

2) Updated patch descriptions to reflect that Valentin Obst's build fix
   for LLVM [1] has already been merged into Linux main.

3) Minor wording and typo corrections in the commit logs throughout.

Changes since the first version:
1) Rebased onto Linux 6.10-rc1

Enjoy!

[1] https://lore.kernel.org/44428518-4d21-4de7-8587-04eceefb330d@nvidia.com

thanks,
John Hubbard

John Hubbard (6):
  selftests/x86: fix Makefile dependencies to work with clang
  selftests/x86: build fsgsbase_restore.c with clang
  selftests/x86: build sysret_rip.c with clang
  selftests/x86: avoid -no-pie warnings from clang during compilation
  selftests/x86: remove (or use) unused variables and functions
  selftests/x86: fix printk warnings reported by clang

Muhammad Usama Anjum (1):
  selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp

 tools/testing/selftests/x86/Makefile          | 31 +++++++++++++++----
 tools/testing/selftests/x86/amx.c             | 16 ----------
 .../testing/selftests/x86/clang_helpers_32.S  | 11 +++++++
 .../testing/selftests/x86/clang_helpers_64.S  | 28 +++++++++++++++++
 tools/testing/selftests/x86/fsgsbase.c        |  6 ----
 .../testing/selftests/x86/fsgsbase_restore.c  | 11 +++----
 tools/testing/selftests/x86/sigreturn.c       |  2 +-
 .../testing/selftests/x86/syscall_arg_fault.c |  1 -
 tools/testing/selftests/x86/sysret_rip.c      | 20 ++++--------
 tools/testing/selftests/x86/test_FISTTP.c     |  8 ++---
 tools/testing/selftests/x86/test_vsyscall.c   | 15 +++------
 tools/testing/selftests/x86/vdso_restorer.c   |  2 ++
 12 files changed, 87 insertions(+), 64 deletions(-)
 create mode 100644 tools/testing/selftests/x86/clang_helpers_32.S
 create mode 100644 tools/testing/selftests/x86/clang_helpers_64.S


base-commit: 795c58e4c7fc6163d8fb9f2baa86cfe898fa4b19
-- 
2.45.2

[PATCH v4 1/7] selftests/x86: fix Makefile dependencies to work with clang

[John Hubbard]

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

...the following build failure occurs in selftests/x86:

   clang: error: cannot specify -o when generating multiple output files

This happens because, although gcc doesn't complain if you invoke it
like this:

    gcc file1.c header2.h

...clang won't accept that form--it rejects the .h file(s). Also, the
above approach is inaccurate anyway, because file.c includes header2.h
in this case, and the inclusion of header2.h on the invocation is an
artifact of the Makefile's desire to maintain dependencies.

In Makefiles of this type, a better way to do it is to use Makefile
dependencies to trigger the appropriate incremental rebuilds, and
separately use file lists (see EXTRA_FILES in this commit) to track what
to pass to the compiler.

This commit splits those concepts up, by setting up both EXTRA_FILES and
the Makefile dependencies with a single call to the new Makefile
function extra-files.

That fixes the build failure, while still providing the correct
dependencies in all cases.

Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/Makefile | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 0b872c0a42d2..c1269466e0f8 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -73,10 +73,10 @@ all_64: $(BINARIES_64)
 EXTRA_CLEAN := $(BINARIES_32) $(BINARIES_64)
 
 $(BINARIES_32): $(OUTPUT)/%_32: %.c helpers.h
-	$(CC) -m32 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl -lm
+	$(CC) -m32 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $< $(EXTRA_FILES) -lrt -ldl -lm
 
 $(BINARIES_64): $(OUTPUT)/%_64: %.c helpers.h
-	$(CC) -m64 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $^ -lrt -ldl
+	$(CC) -m64 -o $@ $(CFLAGS) $(EXTRA_CFLAGS) $< $(EXTRA_FILES) -lrt -ldl
 
 # x86_64 users should be encouraged to install 32-bit libraries
 ifeq ($(CAN_BUILD_I386)$(CAN_BUILD_X86_64),01)
@@ -100,10 +100,19 @@ warn_32bit_failure:
 	exit 0;
 endif
 
-# Some tests have additional dependencies.
-$(OUTPUT)/sysret_ss_attrs_64: thunks.S
-$(OUTPUT)/ptrace_syscall_32: raw_syscall_helper_32.S
-$(OUTPUT)/test_syscall_vdso_32: thunks_32.S
+# Add an additional file to the source file list for a given target, and also
+# add a Makefile dependency on that same file. However, do these separately, so
+# that the compiler invocation ("$(CC) file1.c file2.S") is not combined with
+# the dependencies ("header3.h"), because clang, unlike gcc, will not accept
+# header files as an input to the compiler invocation.
+define extra-files
+$(OUTPUT)/$(1): EXTRA_FILES := $(2)
+$(OUTPUT)/$(1): $(2)
+endef
+
+$(eval $(call extra-files,sysret_ss_attrs_64,thunks.S))
+$(eval $(call extra-files,ptrace_syscall_32,raw_syscall_helper_32.S))
+$(eval $(call extra-files,test_syscall_vdso_32,thunks_32.S))
 
 # check_initial_reg_state is special: it needs a custom entry, and it
 # needs to be static so that its interpreter doesn't destroy its initial
-- 
2.45.2

[PATCH v4 2/7] selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp

[John Hubbard]

From: Muhammad Usama Anjum <usama.anjum@collabora.com>

Use fisttps instead of fisttp to specify correctly that the output
variable is of size short.

test_FISTTP.c:28:3: error: ambiguous instructions require an explicit suffix (could be 'fisttps', or 'fisttpl')
   28 |         "       fisttp  res16""\n"
      |          ^
<inline asm>:3:2: note: instantiated into assembly here
    3 |         fisttp  res16
      |         ^

...followed by three more cases of the same warning for other lines.

[jh: removed a bit of duplication from the warnings report, above, and
     fixed a typo in the title]

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/test_FISTTP.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/x86/test_FISTTP.c b/tools/testing/selftests/x86/test_FISTTP.c
index 09789c0ce3e9..b9ae9d8cebcb 100644
--- a/tools/testing/selftests/x86/test_FISTTP.c
+++ b/tools/testing/selftests/x86/test_FISTTP.c
@@ -25,7 +25,7 @@ int test(void)
 	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
 	asm volatile ("\n"
 	"	fld1""\n"
-	"	fisttp	res16""\n"
+	"	fisttps	res16""\n"
 	"	fld1""\n"
 	"	fisttpl	res32""\n"
 	"	fld1""\n"
@@ -45,7 +45,7 @@ int test(void)
 	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
 	asm volatile ("\n"
 	"	fldpi""\n"
-	"	fisttp	res16""\n"
+	"	fisttps	res16""\n"
 	"	fldpi""\n"
 	"	fisttpl	res32""\n"
 	"	fldpi""\n"
@@ -66,7 +66,7 @@ int test(void)
 	asm volatile ("\n"
 	"	fldpi""\n"
 	"	fchs""\n"
-	"	fisttp	res16""\n"
+	"	fisttps	res16""\n"
 	"	fldpi""\n"
 	"	fchs""\n"
 	"	fisttpl	res32""\n"
@@ -88,7 +88,7 @@ int test(void)
 	feclearexcept(FE_DIVBYZERO|FE_INEXACT|FE_INVALID|FE_OVERFLOW|FE_UNDERFLOW);
 	asm volatile ("\n"
 	"	fldln2""\n"
-	"	fisttp	res16""\n"
+	"	fisttps	res16""\n"
 	"	fldln2""\n"
 	"	fisttpl	res32""\n"
 	"	fldln2""\n"
-- 
2.45.2

[PATCH v4 3/7] selftests/x86: build fsgsbase_restore.c with clang

[John Hubbard]

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

Fix this by moving the inline asm to "pure" assembly, in two new files:
clang_helpers_32.S, clang_helpers_64.S.

As a bonus, the pure asm avoids the need for ifdefs, and is now very
simple and easy on the eyes.

Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/Makefile           |  2 ++
 tools/testing/selftests/x86/clang_helpers_32.S | 11 +++++++++++
 tools/testing/selftests/x86/clang_helpers_64.S | 12 ++++++++++++
 tools/testing/selftests/x86/fsgsbase_restore.c | 11 +++++------
 4 files changed, 30 insertions(+), 6 deletions(-)
 create mode 100644 tools/testing/selftests/x86/clang_helpers_32.S
 create mode 100644 tools/testing/selftests/x86/clang_helpers_64.S

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index c1269466e0f8..99bc2ef84f5a 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -113,6 +113,8 @@ endef
 $(eval $(call extra-files,sysret_ss_attrs_64,thunks.S))
 $(eval $(call extra-files,ptrace_syscall_32,raw_syscall_helper_32.S))
 $(eval $(call extra-files,test_syscall_vdso_32,thunks_32.S))
+$(eval $(call extra-files,fsgsbase_restore_64,clang_helpers_64.S))
+$(eval $(call extra-files,fsgsbase_restore_32,clang_helpers_32.S))
 
 # check_initial_reg_state is special: it needs a custom entry, and it
 # needs to be static so that its interpreter doesn't destroy its initial
diff --git a/tools/testing/selftests/x86/clang_helpers_32.S b/tools/testing/selftests/x86/clang_helpers_32.S
new file mode 100644
index 000000000000..dc16271bac70
--- /dev/null
+++ b/tools/testing/selftests/x86/clang_helpers_32.S
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * 32-bit assembly helpers for asm operations that lack support in both gcc and
+ * clang. For example, clang asm does not support segment prefixes.
+ */
+.global dereference_seg_base
+dereference_seg_base:
+	mov %fs:(0), %eax
+	ret
+
+.section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/x86/clang_helpers_64.S b/tools/testing/selftests/x86/clang_helpers_64.S
new file mode 100644
index 000000000000..0d81c71cad97
--- /dev/null
+++ b/tools/testing/selftests/x86/clang_helpers_64.S
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * 64-bit assembly helpers for asm operations that lack support in both gcc and
+ * clang. For example, clang asm does not support segment prefixes.
+ */
+.global dereference_seg_base
+
+dereference_seg_base:
+	mov %gs:(0), %rax
+	ret
+
+.section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/x86/fsgsbase_restore.c b/tools/testing/selftests/x86/fsgsbase_restore.c
index 6fffadc51579..224058c1e4b2 100644
--- a/tools/testing/selftests/x86/fsgsbase_restore.c
+++ b/tools/testing/selftests/x86/fsgsbase_restore.c
@@ -39,12 +39,11 @@
 # define SEG "%fs"
 #endif
 
-static unsigned int dereference_seg_base(void)
-{
-	int ret;
-	asm volatile ("mov %" SEG ":(0), %0" : "=rm" (ret));
-	return ret;
-}
+/*
+ * Defined in clang_helpers_[32|64].S, because unlike gcc, clang inline asm does
+ * not support segmentation prefixes.
+ */
+unsigned int dereference_seg_base(void);
 
 static void init_seg(void)
 {
-- 
2.45.2

[PATCH v4 4/7] selftests/x86: build sysret_rip.c with clang

[John Hubbard]

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

...the build fails because clang's inline asm doesn't support all of the
features that are used in the asm() snippet in sysret_rip.c.

Fix this by moving the asm code into the clang_helpers_64.S file, where
it can be built with the assembler's full set of features.

Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/Makefile          |  1 +
 .../testing/selftests/x86/clang_helpers_64.S  | 16 +++++++++++++++
 tools/testing/selftests/x86/sysret_rip.c      | 20 ++++++-------------
 3 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index 99bc2ef84f5a..d0bb32bd5538 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -115,6 +115,7 @@ $(eval $(call extra-files,ptrace_syscall_32,raw_syscall_helper_32.S))
 $(eval $(call extra-files,test_syscall_vdso_32,thunks_32.S))
 $(eval $(call extra-files,fsgsbase_restore_64,clang_helpers_64.S))
 $(eval $(call extra-files,fsgsbase_restore_32,clang_helpers_32.S))
+$(eval $(call extra-files,sysret_rip_64,clang_helpers_64.S))
 
 # check_initial_reg_state is special: it needs a custom entry, and it
 # needs to be static so that its interpreter doesn't destroy its initial
diff --git a/tools/testing/selftests/x86/clang_helpers_64.S b/tools/testing/selftests/x86/clang_helpers_64.S
index 0d81c71cad97..185a69dbf39c 100644
--- a/tools/testing/selftests/x86/clang_helpers_64.S
+++ b/tools/testing/selftests/x86/clang_helpers_64.S
@@ -9,4 +9,20 @@ dereference_seg_base:
 	mov %gs:(0), %rax
 	ret
 
+.global test_page
+.global test_syscall_insn
+
+.pushsection ".text", "ax"
+.balign 4096
+test_page: .globl test_page
+	.fill 4094,1,0xcc
+
+test_syscall_insn:
+	syscall
+
+.ifne . - test_page - 4096
+	.error "test page is not one page long"
+.endif
+.popsection
+
 .section .note.GNU-stack,"",%progbits
diff --git a/tools/testing/selftests/x86/sysret_rip.c b/tools/testing/selftests/x86/sysret_rip.c
index 84d74be1d902..b30de9aaa6d4 100644
--- a/tools/testing/selftests/x86/sysret_rip.c
+++ b/tools/testing/selftests/x86/sysret_rip.c
@@ -22,21 +22,13 @@
 #include <sys/mman.h>
 #include <assert.h>
 
-
-asm (
-	".pushsection \".text\", \"ax\"\n\t"
-	".balign 4096\n\t"
-	"test_page: .globl test_page\n\t"
-	".fill 4094,1,0xcc\n\t"
-	"test_syscall_insn:\n\t"
-	"syscall\n\t"
-	".ifne . - test_page - 4096\n\t"
-	".error \"test page is not one page long\"\n\t"
-	".endif\n\t"
-	".popsection"
-    );
-
+/*
+ * These items are in clang_helpers_64.S, in order to avoid clang inline asm
+ * limitations:
+ */
+void test_syscall_ins(void);
 extern const char test_page[];
+
 static void const *current_test_page_addr = test_page;
 
 static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
-- 
2.45.2

[PATCH v4 5/7] selftests/x86: avoid -no-pie warnings from clang during compilation

[John Hubbard]

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

...clang warns that -no-pie is "unused during compilation".

This occurs because clang only wants to see -no-pie during linking.
Here, we don't have a separate linking stage, so a compiler warning is
unavoidable without (wastefully) restructuring the Makefile.

Avoid the warning by simply disabling that warning, for clang builds.

Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/Makefile | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/tools/testing/selftests/x86/Makefile b/tools/testing/selftests/x86/Makefile
index d0bb32bd5538..5c8757a25998 100644
--- a/tools/testing/selftests/x86/Makefile
+++ b/tools/testing/selftests/x86/Makefile
@@ -40,6 +40,13 @@ CFLAGS := -O2 -g -std=gnu99 -pthread -Wall $(KHDR_INCLUDES)
 # call32_from_64 in thunks.S uses absolute addresses.
 ifeq ($(CAN_BUILD_WITH_NOPIE),1)
 CFLAGS += -no-pie
+
+ifneq ($(LLVM),)
+# clang only wants to see -no-pie during linking. Here, we don't have a separate
+# linking stage, so a compiler warning is unavoidable without (wastefully)
+# restructuring the Makefile. Avoid this by simply disabling that warning.
+CFLAGS += -Wno-unused-command-line-argument
+endif
 endif
 
 define gen-target-rule-32
-- 
2.45.2

[PATCH v4 6/7] selftests/x86: remove (or use) unused variables and functions

[John Hubbard]

When building with clang, via:

    make LLVM=1 -C tools/testing/selftests

...quite a few functions are variables are generating "unused" warnings.
Fix the warnings by deleting the unused items.

One item, the "nerrs" variable in vsdo_restorer.c's main(), is unused
but probably wants to be returned from main(), as a non-zero result.
That result is also unused right now, so another option would be to
delete it entirely, but this way, main() also gets fixed. It was missing
a return value.

Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/amx.c               | 16 ----------------
 tools/testing/selftests/x86/fsgsbase.c          |  6 ------
 tools/testing/selftests/x86/syscall_arg_fault.c |  1 -
 tools/testing/selftests/x86/test_vsyscall.c     |  5 -----
 tools/testing/selftests/x86/vdso_restorer.c     |  2 ++
 5 files changed, 2 insertions(+), 28 deletions(-)

diff --git a/tools/testing/selftests/x86/amx.c b/tools/testing/selftests/x86/amx.c
index 95aad6d8849b..1fdf35a4d7f6 100644
--- a/tools/testing/selftests/x86/amx.c
+++ b/tools/testing/selftests/x86/amx.c
@@ -39,16 +39,6 @@ struct xsave_buffer {
 	};
 };
 
-static inline uint64_t xgetbv(uint32_t index)
-{
-	uint32_t eax, edx;
-
-	asm volatile("xgetbv;"
-		     : "=a" (eax), "=d" (edx)
-		     : "c" (index));
-	return eax + ((uint64_t)edx << 32);
-}
-
 static inline void xsave(struct xsave_buffer *xbuf, uint64_t rfbm)
 {
 	uint32_t rfbm_lo = rfbm;
@@ -164,12 +154,6 @@ static inline void clear_xstate_header(struct xsave_buffer *buffer)
 	memset(&buffer->header, 0, sizeof(buffer->header));
 }
 
-static inline uint64_t get_xstatebv(struct xsave_buffer *buffer)
-{
-	/* XSTATE_BV is at the beginning of the header: */
-	return *(uint64_t *)&buffer->header;
-}
-
 static inline void set_xstatebv(struct xsave_buffer *buffer, uint64_t bv)
 {
 	/* XSTATE_BV is at the beginning of the header: */
diff --git a/tools/testing/selftests/x86/fsgsbase.c b/tools/testing/selftests/x86/fsgsbase.c
index 8c780cce941d..50cf32de6313 100644
--- a/tools/testing/selftests/x86/fsgsbase.c
+++ b/tools/testing/selftests/x86/fsgsbase.c
@@ -109,11 +109,6 @@ static inline void wrgsbase(unsigned long gsbase)
 	asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory");
 }
 
-static inline void wrfsbase(unsigned long fsbase)
-{
-	asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory");
-}
-
 enum which_base { FS, GS };
 
 static unsigned long read_base(enum which_base which)
@@ -212,7 +207,6 @@ static void mov_0_gs(unsigned long initial_base, bool schedule)
 }
 
 static volatile unsigned long remote_base;
-static volatile bool remote_hard_zero;
 static volatile unsigned int ftx;
 
 /*
diff --git a/tools/testing/selftests/x86/syscall_arg_fault.c b/tools/testing/selftests/x86/syscall_arg_fault.c
index 461fa41a4d02..48ab065a76f9 100644
--- a/tools/testing/selftests/x86/syscall_arg_fault.c
+++ b/tools/testing/selftests/x86/syscall_arg_fault.c
@@ -29,7 +29,6 @@ static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *),
 		err(1, "sigaction");
 }
 
-static volatile sig_atomic_t sig_traps;
 static sigjmp_buf jmpbuf;
 
 static volatile sig_atomic_t n_errs;
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
index d4c8e8d79d38..1c9895cfc660 100644
--- a/tools/testing/selftests/x86/test_vsyscall.c
+++ b/tools/testing/selftests/x86/test_vsyscall.c
@@ -97,11 +97,6 @@ static inline long sys_gtod(struct timeval *tv, struct timezone *tz)
 	return syscall(SYS_gettimeofday, tv, tz);
 }
 
-static inline int sys_clock_gettime(clockid_t id, struct timespec *ts)
-{
-	return syscall(SYS_clock_gettime, id, ts);
-}
-
 static inline long sys_time(time_t *t)
 {
 	return syscall(SYS_time, t);
diff --git a/tools/testing/selftests/x86/vdso_restorer.c b/tools/testing/selftests/x86/vdso_restorer.c
index fe99f2434155..ac8d8e1e9805 100644
--- a/tools/testing/selftests/x86/vdso_restorer.c
+++ b/tools/testing/selftests/x86/vdso_restorer.c
@@ -92,4 +92,6 @@ int main()
 		printf("[FAIL]\t!SA_SIGINFO handler was not called\n");
 		nerrs++;
 	}
+
+	return nerrs;
 }
-- 
2.45.2

[PATCH v4 7/7] selftests/x86: fix printk warnings reported by clang

[John Hubbard]

These warnings are all of the form, "the format specified a short
(signed or unsigned) int, but the value is a full length int".

Acked-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
---
 tools/testing/selftests/x86/sigreturn.c     |  2 +-
 tools/testing/selftests/x86/test_vsyscall.c | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/x86/sigreturn.c b/tools/testing/selftests/x86/sigreturn.c
index 5d7961a5f7f6..0b75b29f794b 100644
--- a/tools/testing/selftests/x86/sigreturn.c
+++ b/tools/testing/selftests/x86/sigreturn.c
@@ -487,7 +487,7 @@ static void sigtrap(int sig, siginfo_t *info, void *ctx_void)
 	greg_t asm_ss = ctx->uc_mcontext.gregs[REG_CX];
 	if (asm_ss != sig_ss && sig == SIGTRAP) {
 		/* Sanity check failure. */
-		printf("[FAIL]\tSIGTRAP: ss = %hx, frame ss = %hx, ax = %llx\n",
+		printf("[FAIL]\tSIGTRAP: ss = %hx, frame ss = %x, ax = %llx\n",
 		       ss, *ssptr(ctx), (unsigned long long)asm_ss);
 		nerrs++;
 	}
diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c
index 1c9895cfc660..6de11b4df458 100644
--- a/tools/testing/selftests/x86/test_vsyscall.c
+++ b/tools/testing/selftests/x86/test_vsyscall.c
@@ -247,7 +247,7 @@ static void test_getcpu(int cpu)
 
 	if (ret_sys == 0) {
 		if (cpu_sys != cpu)
-			ksft_print_msg("syscall reported CPU %hu but should be %d\n",
+			ksft_print_msg("syscall reported CPU %u but should be %d\n",
 				       cpu_sys, cpu);
 
 		have_node = true;
@@ -265,10 +265,10 @@ static void test_getcpu(int cpu)
 
 			if (cpu_vdso != cpu || node_vdso != node) {
 				if (cpu_vdso != cpu)
-					ksft_print_msg("vDSO reported CPU %hu but should be %d\n",
+					ksft_print_msg("vDSO reported CPU %u but should be %d\n",
 						       cpu_vdso, cpu);
 				if (node_vdso != node)
-					ksft_print_msg("vDSO reported node %hu but should be %hu\n",
+					ksft_print_msg("vDSO reported node %u but should be %u\n",
 						       node_vdso, node);
 				ksft_test_result_fail("Wrong values\n");
 			} else {
@@ -290,10 +290,10 @@ static void test_getcpu(int cpu)
 
 			if (cpu_vsys != cpu || node_vsys != node) {
 				if (cpu_vsys != cpu)
-					ksft_print_msg("vsyscall reported CPU %hu but should be %d\n",
+					ksft_print_msg("vsyscall reported CPU %u but should be %d\n",
 						       cpu_vsys, cpu);
 				if (node_vsys != node)
-					ksft_print_msg("vsyscall reported node %hu but should be %hu\n",
+					ksft_print_msg("vsyscall reported node %u but should be %u\n",
 						       node_vsys, node);
 				ksft_test_result_fail("Wrong values\n");
 			} else {
-- 
2.45.2

Re: [PATCH v4 0/7] selftests/x86: fix build errors and warnings found via clang

[Shuah Khan]

On 7/4/24 01:24, John Hubbard wrote:
> Changes since v3:
> 
> 1) Rebased onto Linux 6.10-rc6+.
> 
> 2) Added Muhammad's acks for the series.
> 
> Cover letter for v3:
> 
> Hi,
> 
> Dave Hansen, Muhammad Usama Anjum, here is the combined series that we
> discussed yesterday [1].
> 
> As I mentioned then, this is a bit intrusive--but no more than
> necessary, IMHO. Specifically, it moves some clang-un-inlineable things
> out to "pure" assembly code files.
> 
> I've tested this by building with clang, then running each binary on my
> x86_64 test system with today's 6.10-rc1, and comparing the console and
> dmesg output to a gcc-based build without these patches applied. Aside
> from timestamps and virtual addresses, it looks identical.
> 
> Earlier cover letter:
> 
> Just a bunch of build and warnings fixes that show up when building with
> clang. Some of these depend on each other, so I'm sending them as a
> series.
> 
> Changes since v2:
> 
> 1) Dropped my test_FISTTP.c patch, and picked up Muhammad's fix instead,
>     seeing as how that was posted first.
> 
> 2) Updated patch descriptions to reflect that Valentin Obst's build fix
>     for LLVM [1] has already been merged into Linux main.
> 
> 3) Minor wording and typo corrections in the commit logs throughout.
> 
> Changes since the first version:
> 1) Rebased onto Linux 6.10-rc1
> 
> Enjoy!
> 
> [1] https://lore.kernel.org/44428518-4d21-4de7-8587-04eceefb330d@nvidia.com
> 
> thanks,
> John Hubbard
> 
> John Hubbard (6):
>    selftests/x86: fix Makefile dependencies to work with clang
>    selftests/x86: build fsgsbase_restore.c with clang
>    selftests/x86: build sysret_rip.c with clang
>    selftests/x86: avoid -no-pie warnings from clang during compilation
>    selftests/x86: remove (or use) unused variables and functions
>    selftests/x86: fix printk warnings reported by clang
> 

> Muhammad Usama Anjum (1):
>    selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp


Usama and John,

I am seeing checkpatch warnings in this series.

v4-3-7
WARNING: externs should be avoided in .c files
#210: FILE: tools/testing/selftests/x86/fsgsbase_restore.c:46:
+unsigned int dereference_seg_base(void);

ARNING: Consecutive strings are generally better as a single string
#156: FILE: tools/testing/selftests/x86/test_FISTTP.c:28:
+	"	fisttps	res16""\n"

WARNING: Consecutive strings are generally better as a single string
#165: FILE: tools/testing/selftests/x86/test_FISTTP.c:48:
+	"	fisttps	res16""\n"

WARNING: Consecutive strings are generally better as a single string
#174: FILE: tools/testing/selftests/x86/test_FISTTP.c:69:
+	"	fisttps	res16""\n"

WARNING: Consecutive strings are generally better as a single string
#183: FILE: tools/testing/selftests/x86/test_FISTTP.c:91:
+	"	fisttps	res16""\n"

total: 0 errors, 5 warnings, 32 lines checked

Can you take a look at these and see if they can be fixed. Send me
v5 with these fixed - I will pull these in for 6.11-rc1

thanks,
-- Shuah

Re: [PATCH v4 0/7] selftests/x86: fix build errors and warnings found via clang

[John Hubbard]

On 7/9/24 1:34 PM, Shuah Khan wrote:
> On 7/4/24 01:24, John Hubbard wrote:
...>> Muhammad Usama Anjum (1):
>>    selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp
> 
> 
> Usama and John,
> 
> I am seeing checkpatch warnings in this series.
> 
> v4-3-7
> WARNING: externs should be avoided in .c files
> #210: FILE: tools/testing/selftests/x86/fsgsbase_restore.c:46:
> +unsigned int dereference_seg_base(void);
> 
> ARNING: Consecutive strings are generally better as a single string
> #156: FILE: tools/testing/selftests/x86/test_FISTTP.c:28:
> +    "    fisttps    res16""\n"
> 
> WARNING: Consecutive strings are generally better as a single string
> #165: FILE: tools/testing/selftests/x86/test_FISTTP.c:48:
> +    "    fisttps    res16""\n"
> 
> WARNING: Consecutive strings are generally better as a single string
> #174: FILE: tools/testing/selftests/x86/test_FISTTP.c:69:
> +    "    fisttps    res16""\n"
> 
> WARNING: Consecutive strings are generally better as a single string
> #183: FILE: tools/testing/selftests/x86/test_FISTTP.c:91:
> +    "    fisttps    res16""\n"
> 
> total: 0 errors, 5 warnings, 32 lines checked
> 
> Can you take a look at these and see if they can be fixed. Send me
> v5 with these fixed - I will pull these in for 6.11-rc1
> 
> thanks,
> -- Shuah

Hi Shuah,

These warnings are pre-existing. For such things, it's usually prudent
to avoid changing them--or at least, not in the same patch.

I think it's best to submit the patch (and series) as-is. If the x86
team wants the above things cleaned up (which I seriously doubt), they'll
let us know.

Yes?


thanks,
-- 
John Hubbard
NVIDIA

Re: [PATCH v4 0/7] selftests/x86: fix build errors and warnings found via clang

[Shuah Khan]

On 7/9/24 14:40, John Hubbard wrote:
> On 7/9/24 1:34 PM, Shuah Khan wrote:
>> On 7/4/24 01:24, John Hubbard wrote:
> ...>> Muhammad Usama Anjum (1):
>>>    selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp
>>
>>
>> Usama and John,
>>
>> I am seeing checkpatch warnings in this series.
>>
>> v4-3-7
>> WARNING: externs should be avoided in .c files
>> #210: FILE: tools/testing/selftests/x86/fsgsbase_restore.c:46:
>> +unsigned int dereference_seg_base(void);

This one looked new though.

thanks,
-- Shuah

Re: [PATCH v4 0/7] selftests/x86: fix build errors and warnings found via clang

[Shuah Khan]

On 7/9/24 14:51, Shuah Khan wrote:
> On 7/9/24 14:40, John Hubbard wrote:
>> On 7/9/24 1:34 PM, Shuah Khan wrote:
>>> On 7/4/24 01:24, John Hubbard wrote:
>> ...>> Muhammad Usama Anjum (1):
>>>>    selftests: x86: test_FISTTP: use fisttps instead of ambiguous fisttp
>>>
>>>
>>> Usama and John,
>>>
>>> I am seeing checkpatch warnings in this series.
>>>
>>> v4-3-7
>>> WARNING: externs should be avoided in .c files
>>> #210: FILE: tools/testing/selftests/x86/fsgsbase_restore.c:46:
>>> +unsigned int dereference_seg_base(void);
> 
> This one looked new though.
> 

Never mind. Looks like there are a few existing warns - pulling
these now for Linux 6.11-rc1.

Thank you both for fixing these.

thanks,
-- Shuah