Messages in this thread Patch in this message | | | From | Jeremy Fitzhardinge <> | Subject | [PATCH 1/5] x86/pvclock: make sure rdtsc doesn't speculate out of region | Date | Mon, 5 Oct 2009 17:50:07 -0700 |
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rdtsc is not necessarily ordered with surrounding instructions so we need to make sure that it doesn't get sampled out of order with respect to reading the time_info.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> --- arch/x86/kernel/pvclock.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c index 03801f2..963f349 100644 --- a/arch/x86/kernel/pvclock.c +++ b/arch/x86/kernel/pvclock.c @@ -117,10 +117,10 @@ cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src) do { version = pvclock_get_time_values(&shadow, src); - barrier(); + rdtsc_barrier(); offset = pvclock_get_nsec_offset(&shadow); ret = shadow.system_timestamp + offset; - barrier(); + rdtsc_barrier(); } while (version != src->version); return ret; -- 1.6.2.5
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