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| author | Linus Torvalds | 2009-06-11 01:15:59 +0200 |
|---|---|---|
| committer | Linus Torvalds | 2009-06-11 01:15:59 +0200 |
| commit | 595dc54a1da91408a52c4b962f3deeb1109aaca0 (patch) | |
| tree | 918dd8ad8bfb44410b16fea7901c3a81111fa831 /arch/x86/kernel/tsc.c | |
| parent | Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/ker... (diff) | |
| parent | x86: move rdtsc_barrier() into the TSC vread method (diff) | |
| download | kernel-qcow2-linux-595dc54a1da91408a52c4b962f3deeb1109aaca0.tar.gz kernel-qcow2-linux-595dc54a1da91408a52c4b962f3deeb1109aaca0.tar.xz kernel-qcow2-linux-595dc54a1da91408a52c4b962f3deeb1109aaca0.zip | |
Merge branch 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: move rdtsc_barrier() into the TSC vread method
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 84d27356c3d0..3e1c057e98fe 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -710,7 +710,16 @@ static cycle_t read_tsc(struct clocksource *cs) #ifdef CONFIG_X86_64 static cycle_t __vsyscall_fn vread_tsc(void) { - cycle_t ret = (cycle_t)vget_cycles(); + cycle_t ret; + + /* + * Surround the RDTSC by barriers, to make sure it's not + * speculated to outside the seqlock critical section and + * does not cause time warps: + */ + rdtsc_barrier(); + ret = (cycle_t)vget_cycles(); + rdtsc_barrier(); return ret >= __vsyscall_gtod_data.clock.cycle_last ? ret : __vsyscall_gtod_data.clock.cycle_last; |