X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=arch%2Fx86%2Fkernel%2Fvsyscall_64.c;fp=arch%2Fx86%2Fkernel%2Fvsyscall_64.c;h=44153afc9067558cef387ba3237ffcf439ca3800;hb=b0f4b285d7ed174804658539129a834270f4829a;hp=6f3d3d4cd97338162e6889f4eaae86b744f2a2ab;hpb=5250d329e38cdf7580faeb9c53c17d3588d7d19c;p=safe%2Fjmp%2Flinux-2.6

diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c
index 6f3d3d4..44153af 100644
--- a/arch/x86/kernel/vsyscall_64.c
+++ b/arch/x86/kernel/vsyscall_64.c
@@ -131,7 +131,16 @@ static __always_inline void do_vgettimeofday(struct timeval * tv)
 			gettimeofday(tv,NULL);
 			return;
 		}
+
+		/*
+		 * 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();
 		now = vread();
+		rdtsc_barrier();
+
 		base = __vsyscall_gtod_data.clock.cycle_last;
 		mask = __vsyscall_gtod_data.clock.mask;
 		mult = __vsyscall_gtod_data.clock.mult;