diff options
| author | Ingo Molnar <mingo@elte.hu> | 2009-06-11 17:55:42 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-06-11 17:55:42 +0200 |
| commit | 940010c5a314a7bd9b498593bc6ba1718ac5aec5 (patch) | |
| tree | d141e08ced08c40c6a8e3ab2cdecde5ff14e560f /arch/x86/kernel/tsc.c | |
| parent | 8dc8e5e8bc0ce00b0f656bf972f67cd8a72759e5 (diff) | |
| parent | 991ec02cdca33b03a132a0cacfe6f0aa0be9aa8d (diff) | |
Merge branch 'linus' into perfcounters/core
Conflicts:
arch/x86/kernel/irqinit.c
arch/x86/kernel/irqinit_64.c
arch/x86/kernel/traps.c
arch/x86/mm/fault.c
include/linux/sched.h
kernel/exit.c
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index d57de05dc43..3e1c057e98f 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -384,13 +384,13 @@ unsigned long native_calibrate_tsc(void) { u64 tsc1, tsc2, delta, ref1, ref2; unsigned long tsc_pit_min = ULONG_MAX, tsc_ref_min = ULONG_MAX; - unsigned long flags, latch, ms, fast_calibrate, tsc_khz; + unsigned long flags, latch, ms, fast_calibrate, hv_tsc_khz; int hpet = is_hpet_enabled(), i, loopmin; - tsc_khz = get_hypervisor_tsc_freq(); - if (tsc_khz) { + hv_tsc_khz = get_hypervisor_tsc_freq(); + if (hv_tsc_khz) { printk(KERN_INFO "TSC: Frequency read from the hypervisor\n"); - return tsc_khz; + return hv_tsc_khz; } local_irq_save(flags); @@ -710,7 +710,16 @@ static cycle_t read_tsc(struct clocksource *cs) #ifdef CONFIG_X86_64 static cycle_t __vsyscall_fn vread_tsc(void) { - cycle_t ret = (cycle_t)vget_cycles(); + cycle_t ret; + + /* + * 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(); + ret = (cycle_t)vget_cycles(); + rdtsc_barrier(); return ret >= __vsyscall_gtod_data.clock.cycle_last ? ret : __vsyscall_gtod_data.clock.cycle_last; |