Messages in this thread Patch in this message | | | From | Ben Hutchings <> | Date | Sun, 03 Feb 2019 14:45:08 +0100 | Subject | [PATCH 3.16 305/305] x86/vdso: Fix vDSO syscall fallback asm constraint regression |
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3.16.63-rc1 review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski <luto@kernel.org>
commit 02e425668f5c9deb42787d10001a3b605993ad15 upstream.
When I added the missing memory outputs, I failed to update the index of the first argument (ebx) on 32-bit builds, which broke the fallbacks. Somehow I must have screwed up my testing or gotten lucky.
Add another test to cover gettimeofday() as well.
Signed-off-by: Andy Lutomirski <luto@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 715bd9d12f84 ("x86/vdso: Fix asm constraints on vDSO syscall fallbacks") Link: http://lkml.kernel.org/r/21bd45ab04b6d838278fa5bebfa9163eceffa13c.1538608971.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> [bwh: Backported to 3.16: - Drop selftest changes - Adjust filename] Tested-by: Matthew Whitehead <tedheadster@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- arch/x86/vdso/vclock_gettime.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
--- a/arch/x86/vdso/vclock_gettime.c +++ b/arch/x86/vdso/vclock_gettime.c @@ -147,11 +147,11 @@ notrace static long vdso_fallback_gettim asm ( "mov %%ebx, %%edx \n" - "mov %2, %%ebx \n" + "mov %[clock], %%ebx \n" "call __kernel_vsyscall \n" "mov %%edx, %%ebx \n" : "=a" (ret), "=m" (*ts) - : "0" (__NR_clock_gettime), "g" (clock), "c" (ts) + : "0" (__NR_clock_gettime), [clock] "g" (clock), "c" (ts) : "memory", "edx"); return ret; } @@ -162,11 +162,11 @@ notrace static long vdso_fallback_gtod(s asm ( "mov %%ebx, %%edx \n" - "mov %2, %%ebx \n" + "mov %[tv], %%ebx \n" "call __kernel_vsyscall \n" "mov %%edx, %%ebx \n" : "=a" (ret), "=m" (*tv), "=m" (*tz) - : "0" (__NR_gettimeofday), "g" (tv), "c" (tz) + : "0" (__NR_gettimeofday), [tv] "g" (tv), "c" (tz) : "memory", "edx"); return ret; }
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