diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index a2c9dd8bfc6f..fb4302738410 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -1006,8 +1006,6 @@ static void __init detect_art(void) /* clocksource code */ -static struct clocksource clocksource_tsc; - static void tsc_resume(struct clocksource *cs) { tsc_verify_tsc_adjust(true); @@ -1058,12 +1056,31 @@ static void tsc_cs_tick_stable(struct clocksource *cs) /* * .mask MUST be CLOCKSOURCE_MASK(64). See comment above read_tsc() */ +static struct clocksource clocksource_tsc_early = { + .name = "tsc-early", + .rating = 299, + .read = read_tsc, + .mask = CLOCKSOURCE_MASK(64), + .flags = CLOCK_SOURCE_IS_CONTINUOUS | + CLOCK_SOURCE_MUST_VERIFY, + .archdata = { .vclock_mode = VCLOCK_TSC }, + .resume = tsc_resume, + .mark_unstable = tsc_cs_mark_unstable, + .tick_stable = tsc_cs_tick_stable, +}; + +/* + * Must mark VALID_FOR_HRES early such that when we unregister tsc_early + * this one will immediately take over. We will only register if TSC has + * been found good. + */ static struct clocksource clocksource_tsc = { .name = "tsc", .rating = 300, .read = read_tsc, .mask = CLOCKSOURCE_MASK(64), .flags = CLOCK_SOURCE_IS_CONTINUOUS | + CLOCK_SOURCE_VALID_FOR_HRES | CLOCK_SOURCE_MUST_VERIFY, .archdata = { .vclock_mode = VCLOCK_TSC }, .resume = tsc_resume, @@ -1187,8 +1204,8 @@ static void tsc_refine_calibration_work(struct work_struct *work) int cpu; /* Don't bother refining TSC on unstable systems */ - if (check_tsc_unstable()) - goto out; + if (tsc_unstable) + return; /* * Since the work is started early in boot, we may be @@ -1240,9 +1257,13 @@ static void tsc_refine_calibration_work(struct work_struct *work) set_cyc2ns_scale(tsc_khz, cpu, tsc_stop); out: + if (tsc_unstable) + return; + if (boot_cpu_has(X86_FEATURE_ART)) art_related_clocksource = &clocksource_tsc; clocksource_register_khz(&clocksource_tsc, tsc_khz); + clocksource_unregister(&clocksource_tsc_early); } @@ -1251,13 +1272,11 @@ static int __init init_tsc_clocksource(void) if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz) return 0; + if (check_tsc_unstable()) + return 0; + if (tsc_clocksource_reliable) clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY; - /* lower the rating if we already know its unstable: */ - if (check_tsc_unstable()) { - clocksource_tsc.rating = 0; - clocksource_tsc.flags &= ~CLOCK_SOURCE_IS_CONTINUOUS; - } if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3)) clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP; @@ -1270,6 +1289,7 @@ static int __init init_tsc_clocksource(void) if (boot_cpu_has(X86_FEATURE_ART)) art_related_clocksource = &clocksource_tsc; clocksource_register_khz(&clocksource_tsc, tsc_khz); + clocksource_unregister(&clocksource_tsc_early); return 0; } @@ -1374,9 +1394,12 @@ void __init tsc_init(void) check_system_tsc_reliable(); - if (unsynchronized_tsc()) + if (unsynchronized_tsc()) { mark_tsc_unstable("TSCs unsynchronized"); + return; + } + clocksource_register_khz(&clocksource_tsc_early, tsc_khz); detect_art(); }