diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 21 | ||||
| -rw-r--r-- | arch/x86/kernel/vsyscall_gtod.c | 23 |
2 files changed, 21 insertions, 23 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index 56b0c338061e..b6025f9e36c6 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -950,7 +950,7 @@ core_initcall(cpufreq_tsc); static struct clocksource clocksource_tsc; /* - * We compare the TSC to the cycle_last value in the clocksource + * We used to compare the TSC to the cycle_last value in the clocksource * structure to avoid a nasty time-warp. This can be observed in a * very small window right after one CPU updated cycle_last under * xtime/vsyscall_gtod lock and the other CPU reads a TSC value which @@ -960,26 +960,23 @@ static struct clocksource clocksource_tsc; * due to the unsigned delta calculation of the time keeping core * code, which is necessary to support wrapping clocksources like pm * timer. + * + * This sanity check is now done in the core timekeeping code. + * checking the result of read_tsc() - cycle_last for being negative. + * That works because CLOCKSOURCE_MASK(64) does not mask out any bit. */ static cycle_t read_tsc(struct clocksource *cs) { - cycle_t ret = (cycle_t)get_cycles(); - - return ret >= clocksource_tsc.cycle_last ? - ret : clocksource_tsc.cycle_last; -} - -static void resume_tsc(struct clocksource *cs) -{ - if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3)) - clocksource_tsc.cycle_last = 0; + return (cycle_t)get_cycles(); } +/* + * .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc() + */ static struct clocksource clocksource_tsc = { .name = "tsc", .rating = 300, .read = read_tsc, - .resume = resume_tsc, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_MUST_VERIFY, diff --git a/arch/x86/kernel/vsyscall_gtod.c b/arch/x86/kernel/vsyscall_gtod.c index 9531fbb123ba..c7d791f32b98 100644 --- a/arch/x86/kernel/vsyscall_gtod.c +++ b/arch/x86/kernel/vsyscall_gtod.c @@ -31,29 +31,30 @@ void update_vsyscall(struct timekeeper *tk) gtod_write_begin(vdata); /* copy vsyscall data */ - vdata->vclock_mode = tk->clock->archdata.vclock_mode; - vdata->cycle_last = tk->clock->cycle_last; - vdata->mask = tk->clock->mask; - vdata->mult = tk->mult; - vdata->shift = tk->shift; + vdata->vclock_mode = tk->tkr.clock->archdata.vclock_mode; + vdata->cycle_last = tk->tkr.cycle_last; + vdata->mask = tk->tkr.mask; + vdata->mult = tk->tkr.mult; + vdata->shift = tk->tkr.shift; vdata->wall_time_sec = tk->xtime_sec; - vdata->wall_time_snsec = tk->xtime_nsec; + vdata->wall_time_snsec = tk->tkr.xtime_nsec; vdata->monotonic_time_sec = tk->xtime_sec + tk->wall_to_monotonic.tv_sec; - vdata->monotonic_time_snsec = tk->xtime_nsec + vdata->monotonic_time_snsec = tk->tkr.xtime_nsec + ((u64)tk->wall_to_monotonic.tv_nsec - << tk->shift); + << tk->tkr.shift); while (vdata->monotonic_time_snsec >= - (((u64)NSEC_PER_SEC) << tk->shift)) { + (((u64)NSEC_PER_SEC) << tk->tkr.shift)) { vdata->monotonic_time_snsec -= - ((u64)NSEC_PER_SEC) << tk->shift; + ((u64)NSEC_PER_SEC) << tk->tkr.shift; vdata->monotonic_time_sec++; } vdata->wall_time_coarse_sec = tk->xtime_sec; - vdata->wall_time_coarse_nsec = (long)(tk->xtime_nsec >> tk->shift); + vdata->wall_time_coarse_nsec = (long)(tk->tkr.xtime_nsec >> + tk->tkr.shift); vdata->monotonic_time_coarse_sec = vdata->wall_time_coarse_sec + tk->wall_to_monotonic.tv_sec; |