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 <[email protected]>
sjhung · Nov 28, 2012 · b01578d · b01578d
1 parent 7069ed6
commit b01578d
Showing 1 changed file with 2 additions and 2 deletions.
diff --git 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) &&