diff options
-rw-r--r-- | arch/x86/kernel/tsc.c | 11 | ||||
-rw-r--r-- | arch/x86/kernel/vsyscall_64.c | 8 |
2 files changed, 10 insertions, 9 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index d57de05dc430..cf8611d991e0 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) | |||
710 | #ifdef CONFIG_X86_64 | 710 | #ifdef CONFIG_X86_64 |
711 | static cycle_t __vsyscall_fn vread_tsc(void) | 711 | static cycle_t __vsyscall_fn vread_tsc(void) |
712 | { | 712 | { |
713 | cycle_t ret = (cycle_t)vget_cycles(); | 713 | cycle_t ret; |
714 | |||
715 | /* | ||
716 | * Surround the RDTSC by barriers, to make sure it's not | ||
717 | * speculated to outside the seqlock critical section and | ||
718 | * does not cause time warps: | ||
719 | */ | ||
720 | rdtsc_barrier(); | ||
721 | ret = (cycle_t)vget_cycles(); | ||
722 | rdtsc_barrier(); | ||
714 | 723 | ||
715 | return ret >= __vsyscall_gtod_data.clock.cycle_last ? | 724 | return ret >= __vsyscall_gtod_data.clock.cycle_last ? |
716 | ret : __vsyscall_gtod_data.clock.cycle_last; | 725 | ret : __vsyscall_gtod_data.clock.cycle_last; |
diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 44153afc9067..25ee06a80aad 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c | |||
@@ -132,15 +132,7 @@ static __always_inline void do_vgettimeofday(struct timeval * tv) | |||
132 | return; | 132 | return; |
133 | } | 133 | } |
134 | 134 | ||
135 | /* | ||
136 | * Surround the RDTSC by barriers, to make sure it's not | ||
137 | * speculated to outside the seqlock critical section and | ||
138 | * does not cause time warps: | ||
139 | */ | ||
140 | rdtsc_barrier(); | ||
141 | now = vread(); | 135 | now = vread(); |
142 | rdtsc_barrier(); | ||
143 | |||
144 | base = __vsyscall_gtod_data.clock.cycle_last; | 136 | base = __vsyscall_gtod_data.clock.cycle_last; |
145 | mask = __vsyscall_gtod_data.clock.mask; | 137 | mask = __vsyscall_gtod_data.clock.mask; |
146 | mult = __vsyscall_gtod_data.clock.mult; | 138 | mult = __vsyscall_gtod_data.clock.mult; |