From b01578de45614c085be319229a52774b61ffe6fb Mon Sep 17 00:00:00 2001
From: Marcelo Tosatti <mtosatti@redhat.com>
Date: Tue, 27 Nov 2012 23:28:49 -0200
Subject: [PATCH] x86: pvclock: make sure rdtsc doesnt speculate out of region
Originally from Jeremy Fitzhardinge.
pvclock_get_time_values, which contains the memory barriers
will be removed by next patch.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
arch/x86/kernel/pvclock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/pvclock.c b/arch/x86/kernel/pvclock.c
index 42eb3300dfc6c..12e47e2104910 100644
--- a/arch/x86/kernel/pvclock.c
+++ b/arch/x86/kernel/pvclock.c
@@ -97,10 +97,10 @@ 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);
if ((valid_flags & PVCLOCK_TSC_STABLE_BIT) &&
--
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