diff options
Diffstat (limited to 'arch/x86/kernel/tsc.c')
| -rw-r--r-- | arch/x86/kernel/tsc.c | 75 |
1 files changed, 59 insertions, 16 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index a78e73da4a74..344698852146 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -48,6 +48,8 @@ static DEFINE_STATIC_KEY_FALSE(__use_tsc); int tsc_clocksource_reliable; +static int __read_mostly tsc_force_recalibrate; + static u32 art_to_tsc_numerator; static u32 art_to_tsc_denominator; static u64 art_to_tsc_offset; @@ -215,7 +217,7 @@ static void __init cyc2ns_init_secondary_cpus(void) /* * Scheduler clock - returns current time in nanosec units. */ -u64 native_sched_clock(void) +noinstr u64 native_sched_clock(void) { if (static_branch_likely(&__use_tsc)) { u64 tsc_now = rdtsc(); @@ -248,7 +250,7 @@ u64 native_sched_clock_from_tsc(u64 tsc) /* We need to define a real function for sched_clock, to override the weak default version */ #ifdef CONFIG_PARAVIRT -unsigned long long sched_clock(void) +noinstr u64 sched_clock(void) { return paravirt_sched_clock(); } @@ -258,8 +260,7 @@ bool using_native_sched_clock(void) return static_call_query(pv_sched_clock) == native_sched_clock; } #else -unsigned long long -sched_clock(void) __attribute__((alias("native_sched_clock"))); +u64 sched_clock(void) __attribute__((alias("native_sched_clock"))); bool using_native_sched_clock(void) { return true; } #endif @@ -292,6 +293,7 @@ __setup("notsc", notsc_setup); static int no_sched_irq_time; static int no_tsc_watchdog; +static int tsc_as_watchdog; static int __init tsc_setup(char *str) { @@ -301,8 +303,22 @@ static int __init tsc_setup(char *str) no_sched_irq_time = 1; if (!strcmp(str, "unstable")) mark_tsc_unstable("boot parameter"); - if (!strcmp(str, "nowatchdog")) + if (!strcmp(str, "nowatchdog")) { no_tsc_watchdog = 1; + if (tsc_as_watchdog) + pr_alert("%s: Overriding earlier tsc=watchdog with tsc=nowatchdog\n", + __func__); + tsc_as_watchdog = 0; + } + if (!strcmp(str, "recalibrate")) + tsc_force_recalibrate = 1; + if (!strcmp(str, "watchdog")) { + if (no_tsc_watchdog) + pr_alert("%s: tsc=watchdog overridden by earlier tsc=nowatchdog\n", + __func__); + else + tsc_as_watchdog = 1; + } return 1; } @@ -912,8 +928,7 @@ void recalibrate_cpu_khz(void) cpu_khz_old, cpu_khz); #endif } - -EXPORT_SYMBOL(recalibrate_cpu_khz); +EXPORT_SYMBOL_GPL(recalibrate_cpu_khz); static unsigned long long cyc2ns_suspend; @@ -1186,6 +1201,12 @@ static void __init tsc_disable_clocksource_watchdog(void) clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY; } +bool tsc_clocksource_watchdog_disabled(void) +{ + return !(clocksource_tsc.flags & CLOCK_SOURCE_MUST_VERIFY) && + tsc_as_watchdog && !no_tsc_watchdog; +} + static void __init check_system_tsc_reliable(void) { #if defined(CONFIG_MGEODEGX1) || defined(CONFIG_MGEODE_LX) || defined(CONFIG_X86_GENERIC) @@ -1374,6 +1395,25 @@ restart: else freq = calc_pmtimer_ref(delta, ref_start, ref_stop); + /* Will hit this only if tsc_force_recalibrate has been set */ + if (boot_cpu_has(X86_FEATURE_TSC_KNOWN_FREQ)) { + + /* Warn if the deviation exceeds 500 ppm */ + if (abs(tsc_khz - freq) > (tsc_khz >> 11)) { + pr_warn("Warning: TSC freq calibrated by CPUID/MSR differs from what is calibrated by HW timer, please check with vendor!!\n"); + pr_info("Previous calibrated TSC freq:\t %lu.%03lu MHz\n", + (unsigned long)tsc_khz / 1000, + (unsigned long)tsc_khz % 1000); + } + + pr_info("TSC freq recalibrated by [%s]:\t %lu.%03lu MHz\n", + hpet ? "HPET" : "PM_TIMER", + (unsigned long)freq / 1000, + (unsigned long)freq % 1000); + + return; + } + /* Make sure we're within 1% */ if (abs(tsc_khz - freq) > tsc_khz/100) goto out; @@ -1407,8 +1447,10 @@ static int __init init_tsc_clocksource(void) if (!boot_cpu_has(X86_FEATURE_TSC) || !tsc_khz) return 0; - if (tsc_unstable) - goto unreg; + if (tsc_unstable) { + clocksource_unregister(&clocksource_tsc_early); + return 0; + } if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3)) clocksource_tsc.flags |= CLOCK_SOURCE_SUSPEND_NONSTOP; @@ -1421,9 +1463,10 @@ 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); -unreg: clocksource_unregister(&clocksource_tsc_early); - return 0; + + if (!tsc_force_recalibrate) + return 0; } schedule_delayed_work(&tsc_irqwork, 0); @@ -1510,6 +1553,11 @@ void __init tsc_early_init(void) void __init tsc_init(void) { + if (!cpu_feature_enabled(X86_FEATURE_TSC)) { + setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); + return; + } + /* * native_calibrate_cpu_early can only calibrate using methods that are * available early in boot. @@ -1517,11 +1565,6 @@ void __init tsc_init(void) if (x86_platform.calibrate_cpu == native_calibrate_cpu_early) x86_platform.calibrate_cpu = native_calibrate_cpu; - if (!boot_cpu_has(X86_FEATURE_TSC)) { - setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); - return; - } - if (!tsc_khz) { /* We failed to determine frequencies earlier, try again */ if (!determine_cpu_tsc_frequencies(false)) { |