diff options
Diffstat (limited to 'arch/x86/kernel/tsc.c')
-rw-r--r-- | arch/x86/kernel/tsc.c | 334 |
1 files changed, 209 insertions, 125 deletions
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c index fb4302738410..e9f777bfed40 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -26,6 +26,7 @@ #include <asm/apic.h> #include <asm/intel-family.h> #include <asm/i8259.h> +#include <asm/uv/uv.h> unsigned int __read_mostly cpu_khz; /* TSC clocks / usec, not used here */ EXPORT_SYMBOL(cpu_khz); @@ -33,16 +34,13 @@ EXPORT_SYMBOL(cpu_khz); unsigned int __read_mostly tsc_khz; EXPORT_SYMBOL(tsc_khz); +#define KHZ 1000 + /* * TSC can be unstable due to cpufreq or due to unsynced TSCs */ static int __read_mostly tsc_unstable; -/* native_sched_clock() is called before tsc_init(), so - we must start with the TSC soft disabled to prevent - erroneous rdtsc usage on !boot_cpu_has(X86_FEATURE_TSC) processors */ -static int __read_mostly tsc_disabled = -1; - static DEFINE_STATIC_KEY_FALSE(__use_tsc); int tsc_clocksource_reliable; @@ -60,7 +58,7 @@ struct cyc2ns { static DEFINE_PER_CPU_ALIGNED(struct cyc2ns, cyc2ns); -void cyc2ns_read_begin(struct cyc2ns_data *data) +void __always_inline cyc2ns_read_begin(struct cyc2ns_data *data) { int seq, idx; @@ -77,7 +75,7 @@ void cyc2ns_read_begin(struct cyc2ns_data *data) } while (unlikely(seq != this_cpu_read(cyc2ns.seq.sequence))); } -void cyc2ns_read_end(void) +void __always_inline cyc2ns_read_end(void) { preempt_enable_notrace(); } @@ -106,24 +104,7 @@ void cyc2ns_read_end(void) * -johnstul@us.ibm.com "math is hard, lets go shopping!" */ -static void cyc2ns_data_init(struct cyc2ns_data *data) -{ - data->cyc2ns_mul = 0; - data->cyc2ns_shift = 0; - data->cyc2ns_offset = 0; -} - -static void __init cyc2ns_init(int cpu) -{ - struct cyc2ns *c2n = &per_cpu(cyc2ns, cpu); - - cyc2ns_data_init(&c2n->data[0]); - cyc2ns_data_init(&c2n->data[1]); - - seqcount_init(&c2n->seq); -} - -static inline unsigned long long cycles_2_ns(unsigned long long cyc) +static __always_inline unsigned long long cycles_2_ns(unsigned long long cyc) { struct cyc2ns_data data; unsigned long long ns; @@ -138,18 +119,11 @@ static inline unsigned long long cycles_2_ns(unsigned long long cyc) return ns; } -static void set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_now) +static void __set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_now) { unsigned long long ns_now; struct cyc2ns_data data; struct cyc2ns *c2n; - unsigned long flags; - - local_irq_save(flags); - sched_clock_idle_sleep_event(); - - if (!khz) - goto done; ns_now = cycles_2_ns(tsc_now); @@ -181,13 +155,56 @@ static void set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_ c2n->data[0] = data; raw_write_seqcount_latch(&c2n->seq); c2n->data[1] = data; +} + +static void set_cyc2ns_scale(unsigned long khz, int cpu, unsigned long long tsc_now) +{ + unsigned long flags; + + local_irq_save(flags); + sched_clock_idle_sleep_event(); + + if (khz) + __set_cyc2ns_scale(khz, cpu, tsc_now); -done: sched_clock_idle_wakeup_event(); local_irq_restore(flags); } /* + * Initialize cyc2ns for boot cpu + */ +static void __init cyc2ns_init_boot_cpu(void) +{ + struct cyc2ns *c2n = this_cpu_ptr(&cyc2ns); + + seqcount_init(&c2n->seq); + __set_cyc2ns_scale(tsc_khz, smp_processor_id(), rdtsc()); +} + +/* + * Secondary CPUs do not run through tsc_init(), so set up + * all the scale factors for all CPUs, assuming the same + * speed as the bootup CPU. (cpufreq notifiers will fix this + * up if their speed diverges) + */ +static void __init cyc2ns_init_secondary_cpus(void) +{ + unsigned int cpu, this_cpu = smp_processor_id(); + struct cyc2ns *c2n = this_cpu_ptr(&cyc2ns); + struct cyc2ns_data *data = c2n->data; + + for_each_possible_cpu(cpu) { + if (cpu != this_cpu) { + seqcount_init(&c2n->seq); + c2n = per_cpu_ptr(&cyc2ns, cpu); + c2n->data[0] = data[0]; + c2n->data[1] = data[1]; + } + } +} + +/* * Scheduler clock - returns current time in nanosec units. */ u64 native_sched_clock(void) @@ -230,7 +247,7 @@ unsigned long long sched_clock(void) bool using_native_sched_clock(void) { - return pv_time_ops.sched_clock == native_sched_clock; + return pv_ops.time.sched_clock == native_sched_clock; } #else unsigned long long @@ -248,8 +265,7 @@ EXPORT_SYMBOL_GPL(check_tsc_unstable); #ifdef CONFIG_X86_TSC int __init notsc_setup(char *str) { - pr_warn("Kernel compiled with CONFIG_X86_TSC, cannot disable TSC completely\n"); - tsc_disabled = 1; + mark_tsc_unstable("boot parameter notsc"); return 1; } #else @@ -317,7 +333,7 @@ static unsigned long calc_hpet_ref(u64 deltatsc, u64 hpet1, u64 hpet2) hpet2 -= hpet1; tmp = ((u64)hpet2 * hpet_readl(HPET_PERIOD)); do_div(tmp, 1000000); - do_div(deltatsc, tmp); + deltatsc = div64_u64(deltatsc, tmp); return (unsigned long) deltatsc; } @@ -620,7 +636,7 @@ unsigned long native_calibrate_tsc(void) case INTEL_FAM6_KABYLAKE_DESKTOP: crystal_khz = 24000; /* 24.0 MHz */ break; - case INTEL_FAM6_ATOM_DENVERTON: + case INTEL_FAM6_ATOM_GOLDMONT_X: crystal_khz = 25000; /* 25.0 MHz */ break; case INTEL_FAM6_ATOM_GOLDMONT: @@ -665,30 +681,17 @@ static unsigned long cpu_khz_from_cpuid(void) return eax_base_mhz * 1000; } -/** - * native_calibrate_cpu - calibrate the cpu on boot +/* + * calibrate cpu using pit, hpet, and ptimer methods. They are available + * later in boot after acpi is initialized. */ -unsigned long native_calibrate_cpu(void) +static unsigned long pit_hpet_ptimer_calibrate_cpu(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; + unsigned long flags, latch, ms; int hpet = is_hpet_enabled(), i, loopmin; - fast_calibrate = cpu_khz_from_cpuid(); - if (fast_calibrate) - return fast_calibrate; - - fast_calibrate = cpu_khz_from_msr(); - if (fast_calibrate) - return fast_calibrate; - - local_irq_save(flags); - fast_calibrate = quick_pit_calibrate(); - local_irq_restore(flags); - if (fast_calibrate) - return fast_calibrate; - /* * Run 5 calibration loops to get the lowest frequency value * (the best estimate). We use two different calibration modes @@ -831,6 +834,37 @@ unsigned long native_calibrate_cpu(void) return tsc_pit_min; } +/** + * native_calibrate_cpu_early - can calibrate the cpu early in boot + */ +unsigned long native_calibrate_cpu_early(void) +{ + unsigned long flags, fast_calibrate = cpu_khz_from_cpuid(); + + if (!fast_calibrate) + fast_calibrate = cpu_khz_from_msr(); + if (!fast_calibrate) { + local_irq_save(flags); + fast_calibrate = quick_pit_calibrate(); + local_irq_restore(flags); + } + return fast_calibrate; +} + + +/** + * native_calibrate_cpu - calibrate the cpu + */ +static unsigned long native_calibrate_cpu(void) +{ + unsigned long tsc_freq = native_calibrate_cpu_early(); + + if (!tsc_freq) + tsc_freq = pit_hpet_ptimer_calibrate_cpu(); + + return tsc_freq; +} + void recalibrate_cpu_khz(void) { #ifndef CONFIG_SMP @@ -1067,6 +1101,7 @@ static struct clocksource clocksource_tsc_early = { .resume = tsc_resume, .mark_unstable = tsc_cs_mark_unstable, .tick_stable = tsc_cs_tick_stable, + .list = LIST_HEAD_INIT(clocksource_tsc_early.list), }; /* @@ -1086,6 +1121,7 @@ static struct clocksource clocksource_tsc = { .resume = tsc_resume, .mark_unstable = tsc_cs_mark_unstable, .tick_stable = tsc_cs_tick_stable, + .list = LIST_HEAD_INIT(clocksource_tsc.list), }; void mark_tsc_unstable(char *reason) @@ -1098,13 +1134,9 @@ void mark_tsc_unstable(char *reason) clear_sched_clock_stable(); disable_sched_clock_irqtime(); pr_info("Marking TSC unstable due to %s\n", reason); - /* Change only the rating, when not registered */ - if (clocksource_tsc.mult) { - clocksource_mark_unstable(&clocksource_tsc); - } else { - clocksource_tsc.flags |= CLOCK_SOURCE_UNSTABLE; - clocksource_tsc.rating = 0; - } + + clocksource_mark_unstable(&clocksource_tsc_early); + clocksource_mark_unstable(&clocksource_tsc); } EXPORT_SYMBOL_GPL(mark_tsc_unstable); @@ -1179,6 +1211,45 @@ struct system_counterval_t convert_art_to_tsc(u64 art) } EXPORT_SYMBOL(convert_art_to_tsc); +/** + * convert_art_ns_to_tsc() - Convert ART in nanoseconds to TSC. + * @art_ns: ART (Always Running Timer) in unit of nanoseconds + * + * PTM requires all timestamps to be in units of nanoseconds. When user + * software requests a cross-timestamp, this function converts system timestamp + * to TSC. + * + * This is valid when CPU feature flag X86_FEATURE_TSC_KNOWN_FREQ is set + * indicating the tsc_khz is derived from CPUID[15H]. Drivers should check + * that this flag is set before conversion to TSC is attempted. + * + * Return: + * struct system_counterval_t - system counter value with the pointer to the + * corresponding clocksource + * @cycles: System counter value + * @cs: Clocksource corresponding to system counter value. Used + * by timekeeping code to verify comparibility of two cycle + * values. + */ + +struct system_counterval_t convert_art_ns_to_tsc(u64 art_ns) +{ + u64 tmp, res, rem; + + rem = do_div(art_ns, USEC_PER_SEC); + + res = art_ns * tsc_khz; + tmp = rem * tsc_khz; + + do_div(tmp, USEC_PER_SEC); + res += tmp; + + return (struct system_counterval_t) { .cs = art_related_clocksource, + .cycles = res}; +} +EXPORT_SYMBOL(convert_art_ns_to_tsc); + + static void tsc_refine_calibration_work(struct work_struct *work); static DECLARE_DELAYED_WORK(tsc_irqwork, tsc_refine_calibration_work); /** @@ -1205,7 +1276,7 @@ static void tsc_refine_calibration_work(struct work_struct *work) /* Don't bother refining TSC on unstable systems */ if (tsc_unstable) - return; + goto unreg; /* * Since the work is started early in boot, we may be @@ -1258,22 +1329,23 @@ static void tsc_refine_calibration_work(struct work_struct *work) out: if (tsc_unstable) - return; + goto unreg; 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); } static int __init init_tsc_clocksource(void) { - if (!boot_cpu_has(X86_FEATURE_TSC) || tsc_disabled > 0 || !tsc_khz) + if (!boot_cpu_has(X86_FEATURE_TSC) || !tsc_khz) return 0; - if (check_tsc_unstable()) - return 0; + if (tsc_unstable) + goto unreg; if (tsc_clocksource_reliable) clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY; @@ -1289,6 +1361,7 @@ 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); +unreg: clocksource_unregister(&clocksource_tsc_early); return 0; } @@ -1302,40 +1375,22 @@ static int __init init_tsc_clocksource(void) */ device_initcall(init_tsc_clocksource); -void __init tsc_early_delay_calibrate(void) +static bool __init determine_cpu_tsc_frequencies(bool early) { - unsigned long lpj; - - if (!boot_cpu_has(X86_FEATURE_TSC)) - return; + /* Make sure that cpu and tsc are not already calibrated */ + WARN_ON(cpu_khz || tsc_khz); - cpu_khz = x86_platform.calibrate_cpu(); - tsc_khz = x86_platform.calibrate_tsc(); - - tsc_khz = tsc_khz ? : cpu_khz; - if (!tsc_khz) - return; - - lpj = tsc_khz * 1000; - do_div(lpj, HZ); - loops_per_jiffy = lpj; -} - -void __init tsc_init(void) -{ - u64 lpj, cyc; - int cpu; - - if (!boot_cpu_has(X86_FEATURE_TSC)) { - setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); - return; + if (early) { + cpu_khz = x86_platform.calibrate_cpu(); + tsc_khz = x86_platform.calibrate_tsc(); + } else { + /* We should not be here with non-native cpu calibration */ + WARN_ON(x86_platform.calibrate_cpu != native_calibrate_cpu); + cpu_khz = pit_hpet_ptimer_calibrate_cpu(); } - cpu_khz = x86_platform.calibrate_cpu(); - tsc_khz = x86_platform.calibrate_tsc(); - /* - * Trust non-zero tsc_khz as authorative, + * Trust non-zero tsc_khz as authoritative, * and use it to sanity check cpu_khz, * which will be off if system timer is off. */ @@ -1344,52 +1399,81 @@ void __init tsc_init(void) else if (abs(cpu_khz - tsc_khz) * 10 > tsc_khz) cpu_khz = tsc_khz; - if (!tsc_khz) { - mark_tsc_unstable("could not calculate TSC khz"); - setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); - return; - } + if (tsc_khz == 0) + return false; pr_info("Detected %lu.%03lu MHz processor\n", - (unsigned long)cpu_khz / 1000, - (unsigned long)cpu_khz % 1000); + (unsigned long)cpu_khz / KHZ, + (unsigned long)cpu_khz % KHZ); if (cpu_khz != tsc_khz) { pr_info("Detected %lu.%03lu MHz TSC", - (unsigned long)tsc_khz / 1000, - (unsigned long)tsc_khz % 1000); + (unsigned long)tsc_khz / KHZ, + (unsigned long)tsc_khz % KHZ); } + return true; +} + +static unsigned long __init get_loops_per_jiffy(void) +{ + u64 lpj = (u64)tsc_khz * KHZ; + do_div(lpj, HZ); + return lpj; +} + +static void __init tsc_enable_sched_clock(void) +{ /* Sanitize TSC ADJUST before cyc2ns gets initialized */ tsc_store_and_check_tsc_adjust(true); + cyc2ns_init_boot_cpu(); + static_branch_enable(&__use_tsc); +} + +void __init tsc_early_init(void) +{ + if (!boot_cpu_has(X86_FEATURE_TSC)) + return; + /* Don't change UV TSC multi-chassis synchronization */ + if (is_early_uv_system()) + return; + if (!determine_cpu_tsc_frequencies(true)) + return; + loops_per_jiffy = get_loops_per_jiffy(); + + tsc_enable_sched_clock(); +} +void __init tsc_init(void) +{ /* - * Secondary CPUs do not run through tsc_init(), so set up - * all the scale factors for all CPUs, assuming the same - * speed as the bootup CPU. (cpufreq notifiers will fix this - * up if their speed diverges) + * native_calibrate_cpu_early can only calibrate using methods that are + * available early in boot. */ - cyc = rdtsc(); - for_each_possible_cpu(cpu) { - cyc2ns_init(cpu); - set_cyc2ns_scale(tsc_khz, cpu, cyc); - } + if (x86_platform.calibrate_cpu == native_calibrate_cpu_early) + x86_platform.calibrate_cpu = native_calibrate_cpu; - if (tsc_disabled > 0) + if (!boot_cpu_has(X86_FEATURE_TSC)) { + setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); return; + } - /* now allow native_sched_clock() to use rdtsc */ + if (!tsc_khz) { + /* We failed to determine frequencies earlier, try again */ + if (!determine_cpu_tsc_frequencies(false)) { + mark_tsc_unstable("could not calculate TSC khz"); + setup_clear_cpu_cap(X86_FEATURE_TSC_DEADLINE_TIMER); + return; + } + tsc_enable_sched_clock(); + } - tsc_disabled = 0; - static_branch_enable(&__use_tsc); + cyc2ns_init_secondary_cpus(); if (!no_sched_irq_time) enable_sched_clock_irqtime(); - lpj = ((u64)tsc_khz * 1000); - do_div(lpj, HZ); - lpj_fine = lpj; - + lpj_fine = get_loops_per_jiffy(); use_tsc_delay(); check_system_tsc_reliable(); @@ -1416,7 +1500,7 @@ unsigned long calibrate_delay_is_known(void) int constant_tsc = cpu_has(&cpu_data(cpu), X86_FEATURE_CONSTANT_TSC); const struct cpumask *mask = topology_core_cpumask(cpu); - if (tsc_disabled || !constant_tsc || !mask) + if (!constant_tsc || !mask) return 0; sibling = cpumask_any_but(mask, cpu); |