diff --git a/Documentation/devicetree/bindings/timer/renesas,ostm.yaml b/Documentation/devicetree/bindings/timer/renesas,ostm.yaml index 8b06a681764e..e8c642166462 100644 --- a/Documentation/devicetree/bindings/timer/renesas,ostm.yaml +++ b/Documentation/devicetree/bindings/timer/renesas,ostm.yaml @@ -26,6 +26,7 @@ properties: - renesas,r9a07g043-ostm # RZ/G2UL and RZ/Five - renesas,r9a07g044-ostm # RZ/G2{L,LC} - renesas,r9a07g054-ostm # RZ/V2L + - renesas,r9a09g057-ostm # RZ/V2H(P) - const: renesas,ostm # Generic reg: @@ -58,6 +59,7 @@ if: - renesas,r9a07g043-ostm - renesas,r9a07g044-ostm - renesas,r9a07g054-ostm + - renesas,r9a09g057-ostm then: required: - resets diff --git a/arch/powerpc/include/asm/vdso/gettimeofday.h b/arch/powerpc/include/asm/vdso/gettimeofday.h index 78302f6c2580..c6390890a60c 100644 --- a/arch/powerpc/include/asm/vdso/gettimeofday.h +++ b/arch/powerpc/include/asm/vdso/gettimeofday.h @@ -13,6 +13,17 @@ #define VDSO_HAS_TIME 1 +/* + * powerpc specific delta calculation. + * + * This variant removes the masking of the subtraction because the + * clocksource mask of all VDSO capable clocksources on powerpc is U64_MAX + * which would result in a pointless operation. The compiler cannot + * optimize it away as the mask comes from the vdso data and is not compile + * time constant. + */ +#define VDSO_DELTA_NOMASK 1 + static __always_inline int do_syscall_2(const unsigned long _r0, const unsigned long _r3, const unsigned long _r4) { @@ -104,21 +115,6 @@ static inline bool vdso_clocksource_ok(const struct vdso_data *vd) } #define vdso_clocksource_ok vdso_clocksource_ok -/* - * powerpc specific delta calculation. - * - * This variant removes the masking of the subtraction because the - * clocksource mask of all VDSO capable clocksources on powerpc is U64_MAX - * which would result in a pointless operation. The compiler cannot - * optimize it away as the mask comes from the vdso data and is not compile - * time constant. - */ -static __always_inline u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) -{ - return (cycles - last) * mult; -} -#define vdso_calc_delta vdso_calc_delta - #ifndef __powerpc64__ static __always_inline u64 vdso_shift_ns(u64 ns, unsigned long shift) { diff --git a/arch/s390/include/asm/vdso/gettimeofday.h b/arch/s390/include/asm/vdso/gettimeofday.h index db84942eb78f..7937765ccfa5 100644 --- a/arch/s390/include/asm/vdso/gettimeofday.h +++ b/arch/s390/include/asm/vdso/gettimeofday.h @@ -6,16 +6,13 @@ #define VDSO_HAS_CLOCK_GETRES 1 +#define VDSO_DELTA_NOMASK 1 + #include #include #include #include -#define vdso_calc_delta __arch_vdso_calc_delta -static __always_inline u64 __arch_vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) -{ - return (cycles - last) * mult; -} static __always_inline const struct vdso_data *__arch_get_vdso_data(void) { diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index fe196f49d278..07e8817278a4 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -169,6 +169,7 @@ config X86 select GENERIC_TIME_VSYSCALL select GENERIC_GETTIMEOFDAY select GENERIC_VDSO_TIME_NS + select GENERIC_VDSO_OVERFLOW_PROTECT select GUP_GET_PXX_LOW_HIGH if X86_PAE select HARDIRQS_SW_RESEND select HARDLOCKUP_CHECK_TIMESTAMP if X86_64 diff --git a/arch/x86/include/asm/vdso/gettimeofday.h b/arch/x86/include/asm/vdso/gettimeofday.h index 8e048ca980df..0ef36190abe6 100644 --- a/arch/x86/include/asm/vdso/gettimeofday.h +++ b/arch/x86/include/asm/vdso/gettimeofday.h @@ -300,7 +300,7 @@ static inline bool arch_vdso_cycles_ok(u64 cycles) #define vdso_cycles_ok arch_vdso_cycles_ok /* - * x86 specific delta calculation. + * x86 specific calculation of nanoseconds for the current cycle count * * The regular implementation assumes that clocksource reads are globally * monotonic. The TSC can be slightly off across sockets which can cause @@ -308,8 +308,8 @@ static inline bool arch_vdso_cycles_ok(u64 cycles) * jump. * * Therefore it needs to be verified that @cycles are greater than - * @last. If not then use @last, which is the base time of the current - * conversion period. + * @vd->cycles_last. If not then use @vd->cycles_last, which is the base + * time of the current conversion period. * * This variant also uses a custom mask because while the clocksource mask of * all the VDSO capable clocksources on x86 is U64_MAX, the above code uses @@ -317,25 +317,37 @@ static inline bool arch_vdso_cycles_ok(u64 cycles) * declares everything with the MSB/Sign-bit set as invalid. Therefore the * effective mask is S64_MAX. */ -static __always_inline -u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) +static __always_inline u64 vdso_calc_ns(const struct vdso_data *vd, u64 cycles, u64 base) { + u64 delta = cycles - vd->cycle_last; + /* + * Negative motion and deltas which can cause multiplication + * overflow require special treatment. This check covers both as + * negative motion is guaranteed to be greater than @vd::max_cycles + * due to unsigned comparison. + * * Due to the MSB/Sign-bit being used as invalid marker (see - * arch_vdso_cycles_valid() above), the effective mask is S64_MAX. + * arch_vdso_cycles_valid() above), the effective mask is S64_MAX, + * but that case is also unlikely and will also take the unlikely path + * here. */ - u64 delta = (cycles - last) & S64_MAX; + if (unlikely(delta > vd->max_cycles)) { + /* + * Due to the above mentioned TSC wobbles, filter out + * negative motion. Per the above masking, the effective + * sign bit is now bit 62. + */ + if (delta & (1ULL << 62)) + return base >> vd->shift; - /* - * Due to the above mentioned TSC wobbles, filter out negative motion. - * Per the above masking, the effective sign bit is now bit 62. - */ - if (unlikely(delta & (1ULL << 62))) - return 0; + /* Handle multiplication overflow gracefully */ + return mul_u64_u32_add_u64_shr(delta & S64_MAX, vd->mult, base, vd->shift); + } - return delta * mult; + return ((delta * vd->mult) + base) >> vd->shift; } -#define vdso_calc_delta vdso_calc_delta +#define vdso_calc_ns vdso_calc_ns #endif /* !__ASSEMBLY__ */ diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 8d4a52056684..5bb43cc1a8df 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -331,7 +331,7 @@ static u64 notrace hisi_161010101_read_cntvct_el0(void) return __hisi_161010101_read_reg(cntvct_el0); } -static struct ate_acpi_oem_info hisi_161010101_oem_info[] = { +static const struct ate_acpi_oem_info hisi_161010101_oem_info[] = { /* * Note that trailing spaces are required to properly match * the OEM table information. diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c index 8da972dc1713..3fcbd02b2483 100644 --- a/drivers/clocksource/renesas-ostm.c +++ b/drivers/clocksource/renesas-ostm.c @@ -210,6 +210,7 @@ static int __init ostm_init(struct device_node *np) pr_info("%pOF: used for clock events\n", np); } + of_node_set_flag(np, OF_POPULATED); return 0; err_cleanup: @@ -224,7 +225,7 @@ static int __init ostm_init(struct device_node *np) TIMER_OF_DECLARE(ostm, "renesas,ostm", ostm_init); -#ifdef CONFIG_ARCH_RZG2L +#if defined(CONFIG_ARCH_RZG2L) || defined(CONFIG_ARCH_R9A09G057) static int __init ostm_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; diff --git a/drivers/clocksource/timer-ti-dm.c b/drivers/clocksource/timer-ti-dm.c index 56acf2617262..b7a34b1a975e 100644 --- a/drivers/clocksource/timer-ti-dm.c +++ b/drivers/clocksource/timer-ti-dm.c @@ -129,7 +129,6 @@ struct dmtimer { void __iomem *func_base; /* function register base */ atomic_t enabled; - unsigned long rate; unsigned reserved:1; unsigned posted:1; unsigned omap1:1; diff --git a/include/linux/math64.h b/include/linux/math64.h index bf74478926d4..d34def7f9a8c 100644 --- a/include/linux/math64.h +++ b/include/linux/math64.h @@ -4,8 +4,8 @@ #include #include -#include #include +#include #if BITS_PER_LONG == 64 @@ -179,16 +179,12 @@ static __always_inline u64 mul_u64_u64_shr(u64 a, u64 mul, unsigned int shift) #ifndef mul_u64_u32_shr static __always_inline u64 mul_u64_u32_shr(u64 a, u32 mul, unsigned int shift) { - u32 ah, al; + u32 ah = a >> 32, al = a; u64 ret; - al = a; - ah = a >> 32; - ret = mul_u32_u32(al, mul) >> shift; if (ah) ret += mul_u32_u32(ah, mul) << (32 - shift); - return ret; } #endif /* mul_u64_u32_shr */ diff --git a/include/linux/timerqueue.h b/include/linux/timerqueue.h index 62973f7d4610..d306d9dd2207 100644 --- a/include/linux/timerqueue.h +++ b/include/linux/timerqueue.h @@ -37,11 +37,6 @@ static inline bool timerqueue_node_queued(struct timerqueue_node *node) return !RB_EMPTY_NODE(&node->node); } -static inline bool timerqueue_node_expires(struct timerqueue_node *node) -{ - return node->expires; -} - static inline void timerqueue_init_head(struct timerqueue_head *head) { head->rb_root = RB_ROOT_CACHED; diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h index c71ddb6d4691..d04d394db064 100644 --- a/include/vdso/datapage.h +++ b/include/vdso/datapage.h @@ -61,6 +61,7 @@ struct vdso_timestamp { * @seq: timebase sequence counter * @clock_mode: clock mode * @cycle_last: timebase at clocksource init + * @max_cycles: maximum cycles which won't overflow 64bit multiplication * @mask: clocksource mask * @mult: clocksource multiplier * @shift: clocksource shift @@ -92,6 +93,9 @@ struct vdso_data { s32 clock_mode; u64 cycle_last; +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT + u64 max_cycles; +#endif u64 mask; u32 mult; u32 shift; diff --git a/include/vdso/math64.h b/include/vdso/math64.h index 7da703ee5561..22ae212f8b28 100644 --- a/include/vdso/math64.h +++ b/include/vdso/math64.h @@ -21,4 +21,42 @@ __iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder) return ret; } +#if defined(CONFIG_ARCH_SUPPORTS_INT128) && defined(__SIZEOF_INT128__) + +#ifndef mul_u64_u32_add_u64_shr +static __always_inline u64 mul_u64_u32_add_u64_shr(u64 a, u32 mul, u64 b, unsigned int shift) +{ + return (u64)((((unsigned __int128)a * mul) + b) >> shift); +} +#endif /* mul_u64_u32_add_u64_shr */ + +#else + +#ifndef mul_u64_u32_add_u64_shr +#ifndef mul_u32_u32 +static inline u64 mul_u32_u32(u32 a, u32 b) +{ + return (u64)a * b; +} +#define mul_u32_u32 mul_u32_u32 +#endif +static __always_inline u64 mul_u64_u32_add_u64_shr(u64 a, u32 mul, u64 b, unsigned int shift) +{ + u32 ah = a >> 32, al = a; + bool ovf; + u64 ret; + + ovf = __builtin_add_overflow(mul_u32_u32(al, mul), b, &ret); + ret >>= shift; + if (ovf && shift) + ret += 1ULL << (64 - shift); + if (ah) + ret += mul_u32_u32(ah, mul) << (32 - shift); + + return ret; +} +#endif /* mul_u64_u32_add_u64_shr */ + +#endif + #endif /* __VDSO_MATH64_H */ diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index fc3b1a06c981..8ebb6d5a106b 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -202,7 +202,7 @@ config HIGH_RES_TIMERS the size of the kernel image. config CLOCKSOURCE_WATCHDOG_MAX_SKEW_US - int "Clocksource watchdog maximum allowable skew (in μs)" + int "Clocksource watchdog maximum allowable skew (in microseconds)" depends on CLOCKSOURCE_WATCHDOG range 50 1000 default 125 diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c index a7ca458cdd9c..60a6484831b1 100644 --- a/kernel/time/clockevents.c +++ b/kernel/time/clockevents.c @@ -677,7 +677,7 @@ static ssize_t current_device_show(struct device *dev, raw_spin_lock_irq(&clockevents_lock); td = tick_get_tick_dev(dev); if (td && td->evtdev) - count = snprintf(buf, PAGE_SIZE, "%s\n", td->evtdev->name); + count = sysfs_emit(buf, "%s\n", td->evtdev->name); raw_spin_unlock_irq(&clockevents_lock); return count; } diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index e5b260aa0e02..d25ba49e313c 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -20,6 +20,16 @@ #include "tick-internal.h" #include "timekeeping_internal.h" +static noinline u64 cycles_to_nsec_safe(struct clocksource *cs, u64 start, u64 end) +{ + u64 delta = clocksource_delta(end, start, cs->mask); + + if (likely(delta < cs->max_cycles)) + return clocksource_cyc2ns(delta, cs->mult, cs->shift); + + return mul_u64_u32_shr(delta, cs->mult, cs->shift); +} + /** * clocks_calc_mult_shift - calculate mult/shift factors for scaled math of clocks * @mult: pointer to mult variable @@ -222,8 +232,8 @@ enum wd_read_status { static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow, u64 *wdnow) { unsigned int nretries, max_retries; - u64 wd_end, wd_end2, wd_delta; int64_t wd_delay, wd_seq_delay; + u64 wd_end, wd_end2; max_retries = clocksource_get_max_watchdog_retry(); for (nretries = 0; nretries <= max_retries; nretries++) { @@ -234,9 +244,7 @@ static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow, wd_end2 = watchdog->read(watchdog); local_irq_enable(); - wd_delta = clocksource_delta(wd_end, *wdnow, watchdog->mask); - wd_delay = clocksource_cyc2ns(wd_delta, watchdog->mult, - watchdog->shift); + wd_delay = cycles_to_nsec_safe(watchdog, *wdnow, wd_end); if (wd_delay <= WATCHDOG_MAX_SKEW) { if (nretries > 1 || nretries >= max_retries) { pr_warn("timekeeping watchdog on CPU%d: %s retried %d times before success\n", @@ -254,8 +262,7 @@ static enum wd_read_status cs_watchdog_read(struct clocksource *cs, u64 *csnow, * report system busy, reinit the watchdog and skip the current * watchdog test. */ - wd_delta = clocksource_delta(wd_end2, wd_end, watchdog->mask); - wd_seq_delay = clocksource_cyc2ns(wd_delta, watchdog->mult, watchdog->shift); + wd_seq_delay = cycles_to_nsec_safe(watchdog, wd_end, wd_end2); if (wd_seq_delay > WATCHDOG_MAX_SKEW/2) goto skip_test; } @@ -366,8 +373,7 @@ void clocksource_verify_percpu(struct clocksource *cs) delta = (csnow_end - csnow_mid) & cs->mask; if (delta < 0) cpumask_set_cpu(cpu, &cpus_ahead); - delta = clocksource_delta(csnow_end, csnow_begin, cs->mask); - cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift); + cs_nsec = cycles_to_nsec_safe(cs, csnow_begin, csnow_end); if (cs_nsec > cs_nsec_max) cs_nsec_max = cs_nsec; if (cs_nsec < cs_nsec_min) @@ -398,8 +404,8 @@ static inline void clocksource_reset_watchdog(void) static void clocksource_watchdog(struct timer_list *unused) { - u64 csnow, wdnow, cslast, wdlast, delta; int64_t wd_nsec, cs_nsec, interval; + u64 csnow, wdnow, cslast, wdlast; int next_cpu, reset_pending; struct clocksource *cs; enum wd_read_status read_ret; @@ -456,12 +462,8 @@ static void clocksource_watchdog(struct timer_list *unused) continue; } - delta = clocksource_delta(wdnow, cs->wd_last, watchdog->mask); - wd_nsec = clocksource_cyc2ns(delta, watchdog->mult, - watchdog->shift); - - delta = clocksource_delta(csnow, cs->cs_last, cs->mask); - cs_nsec = clocksource_cyc2ns(delta, cs->mult, cs->shift); + wd_nsec = cycles_to_nsec_safe(watchdog, cs->wd_last, wdnow); + cs_nsec = cycles_to_nsec_safe(cs, cs->cs_last, csnow); wdlast = cs->wd_last; /* save these in case we print them */ cslast = cs->cs_last; cs->cs_last = csnow; @@ -832,7 +834,7 @@ void clocksource_start_suspend_timing(struct clocksource *cs, u64 start_cycles) */ u64 clocksource_stop_suspend_timing(struct clocksource *cs, u64 cycle_now) { - u64 now, delta, nsec = 0; + u64 now, nsec = 0; if (!suspend_clocksource) return 0; @@ -847,12 +849,8 @@ u64 clocksource_stop_suspend_timing(struct clocksource *cs, u64 cycle_now) else now = suspend_clocksource->read(suspend_clocksource); - if (now > suspend_start) { - delta = clocksource_delta(now, suspend_start, - suspend_clocksource->mask); - nsec = mul_u64_u32_shr(delta, suspend_clocksource->mult, - suspend_clocksource->shift); - } + if (now > suspend_start) + nsec = cycles_to_nsec_safe(suspend_clocksource, suspend_start, now); /* * Disable the suspend timer to save power if current clocksource is @@ -1336,7 +1334,7 @@ static ssize_t current_clocksource_show(struct device *dev, ssize_t count = 0; mutex_lock(&clocksource_mutex); - count = snprintf(buf, PAGE_SIZE, "%s\n", curr_clocksource->name); + count = sysfs_emit(buf, "%s\n", curr_clocksource->name); mutex_unlock(&clocksource_mutex); return count; diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c index 70625dff62ce..492c14aac642 100644 --- a/kernel/time/hrtimer.c +++ b/kernel/time/hrtimer.c @@ -644,17 +644,12 @@ static inline ktime_t hrtimer_update_base(struct hrtimer_cpu_base *base) /* * Is the high resolution mode active ? */ -static inline int __hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base) +static inline int hrtimer_hres_active(struct hrtimer_cpu_base *cpu_base) { return IS_ENABLED(CONFIG_HIGH_RES_TIMERS) ? cpu_base->hres_active : 0; } -static inline int hrtimer_hres_active(void) -{ - return __hrtimer_hres_active(this_cpu_ptr(&hrtimer_bases)); -} - static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base, struct hrtimer *next_timer, ktime_t expires_next) @@ -678,7 +673,7 @@ static void __hrtimer_reprogram(struct hrtimer_cpu_base *cpu_base, * set. So we'd effectively block all timers until the T2 event * fires. */ - if (!__hrtimer_hres_active(cpu_base) || cpu_base->hang_detected) + if (!hrtimer_hres_active(cpu_base) || cpu_base->hang_detected) return; tick_program_event(expires_next, 1); @@ -789,12 +784,12 @@ static void retrigger_next_event(void *arg) * function call will take care of the reprogramming in case the * CPU was in a NOHZ idle sleep. */ - if (!__hrtimer_hres_active(base) && !tick_nohz_active) + if (!hrtimer_hres_active(base) && !tick_nohz_active) return; raw_spin_lock(&base->lock); hrtimer_update_base(base); - if (__hrtimer_hres_active(base)) + if (hrtimer_hres_active(base)) hrtimer_force_reprogram(base, 0); else hrtimer_update_next_event(base); @@ -951,7 +946,7 @@ void clock_was_set(unsigned int bases) cpumask_var_t mask; int cpu; - if (!__hrtimer_hres_active(cpu_base) && !tick_nohz_active) + if (!hrtimer_hres_active(cpu_base) && !tick_nohz_active) goto out_timerfd; if (!zalloc_cpumask_var(&mask, GFP_KERNEL)) { @@ -1491,7 +1486,7 @@ u64 hrtimer_get_next_event(void) raw_spin_lock_irqsave(&cpu_base->lock, flags); - if (!__hrtimer_hres_active(cpu_base)) + if (!hrtimer_hres_active(cpu_base)) expires = __hrtimer_get_next_event(cpu_base, HRTIMER_ACTIVE_ALL); raw_spin_unlock_irqrestore(&cpu_base->lock, flags); @@ -1514,7 +1509,7 @@ u64 hrtimer_next_event_without(const struct hrtimer *exclude) raw_spin_lock_irqsave(&cpu_base->lock, flags); - if (__hrtimer_hres_active(cpu_base)) { + if (hrtimer_hres_active(cpu_base)) { unsigned int active; if (!cpu_base->softirq_activated) { @@ -1875,25 +1870,7 @@ void hrtimer_interrupt(struct clock_event_device *dev) tick_program_event(expires_next, 1); pr_warn_once("hrtimer: interrupt took %llu ns\n", ktime_to_ns(delta)); } - -/* called with interrupts disabled */ -static inline void __hrtimer_peek_ahead_timers(void) -{ - struct tick_device *td; - - if (!hrtimer_hres_active()) - return; - - td = this_cpu_ptr(&tick_cpu_device); - if (td && td->evtdev) - hrtimer_interrupt(td->evtdev); -} - -#else /* CONFIG_HIGH_RES_TIMERS */ - -static inline void __hrtimer_peek_ahead_timers(void) { } - -#endif /* !CONFIG_HIGH_RES_TIMERS */ +#endif /* !CONFIG_HIGH_RES_TIMERS */ /* * Called from run_local_timers in hardirq context every jiffy @@ -1904,7 +1881,7 @@ void hrtimer_run_queues(void) unsigned long flags; ktime_t now; - if (__hrtimer_hres_active(cpu_base)) + if (hrtimer_hres_active(cpu_base)) return; /* diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index b58dffc58a8f..4e18db1819f8 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -237,7 +237,9 @@ static void timekeeping_check_update(struct timekeeper *tk, u64 offset) } } -static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr) +static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles); + +static inline u64 timekeeping_debug_get_ns(const struct tk_read_base *tkr) { struct timekeeper *tk = &tk_core.timekeeper; u64 now, last, mask, max, delta; @@ -264,34 +266,23 @@ static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr) * Try to catch underflows by checking if we are seeing small * mask-relative negative values. */ - if (unlikely((~delta & mask) < (mask >> 3))) { + if (unlikely((~delta & mask) < (mask >> 3))) tk->underflow_seen = 1; - delta = 0; - } - /* Cap delta value to the max_cycles values to avoid mult overflows */ - if (unlikely(delta > max)) { + /* Check for multiplication overflows */ + if (unlikely(delta > max)) tk->overflow_seen = 1; - delta = tkr->clock->max_cycles; - } - return delta; + /* timekeeping_cycles_to_ns() handles both under and overflow */ + return timekeeping_cycles_to_ns(tkr, now); } #else static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset) { } -static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr) +static inline u64 timekeeping_debug_get_ns(const struct tk_read_base *tkr) { - u64 cycle_now, delta; - - /* read clocksource */ - cycle_now = tk_clock_read(tkr); - - /* calculate the delta since the last update_wall_time */ - delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask); - - return delta; + BUG(); } #endif @@ -370,32 +361,46 @@ static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock) } /* Timekeeper helper functions. */ - -static inline u64 timekeeping_delta_to_ns(const struct tk_read_base *tkr, u64 delta) +static noinline u64 delta_to_ns_safe(const struct tk_read_base *tkr, u64 delta) { - u64 nsec; - - nsec = delta * tkr->mult + tkr->xtime_nsec; - nsec >>= tkr->shift; - - return nsec; -} - -static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr) -{ - u64 delta; - - delta = timekeeping_get_delta(tkr); - return timekeeping_delta_to_ns(tkr, delta); + return mul_u64_u32_add_u64_shr(delta, tkr->mult, tkr->xtime_nsec, tkr->shift); } static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles) { - u64 delta; + /* Calculate the delta since the last update_wall_time() */ + u64 mask = tkr->mask, delta = (cycles - tkr->cycle_last) & mask; - /* calculate the delta since the last update_wall_time */ - delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask); - return timekeeping_delta_to_ns(tkr, delta); + /* + * This detects both negative motion and the case where the delta + * overflows the multiplication with tkr->mult. + */ + if (unlikely(delta > tkr->clock->max_cycles)) { + /* + * Handle clocksource inconsistency between CPUs to prevent + * time from going backwards by checking for the MSB of the + * mask being set in the delta. + */ + if (delta & ~(mask >> 1)) + return tkr->xtime_nsec >> tkr->shift; + + return delta_to_ns_safe(tkr, delta); + } + + return ((delta * tkr->mult) + tkr->xtime_nsec) >> tkr->shift; +} + +static __always_inline u64 __timekeeping_get_ns(const struct tk_read_base *tkr) +{ + return timekeeping_cycles_to_ns(tkr, tk_clock_read(tkr)); +} + +static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr) +{ + if (IS_ENABLED(CONFIG_DEBUG_TIMEKEEPING)) + return timekeeping_debug_get_ns(tkr); + + return __timekeeping_get_ns(tkr); } /** @@ -431,14 +436,6 @@ static void update_fast_timekeeper(const struct tk_read_base *tkr, memcpy(base + 1, base, sizeof(*base)); } -static __always_inline u64 fast_tk_get_delta_ns(struct tk_read_base *tkr) -{ - u64 delta, cycles = tk_clock_read(tkr); - - delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask); - return timekeeping_delta_to_ns(tkr, delta); -} - static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf) { struct tk_read_base *tkr; @@ -449,7 +446,7 @@ static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf) seq = raw_read_seqcount_latch(&tkf->seq); tkr = tkf->base + (seq & 0x01); now = ktime_to_ns(tkr->base); - now += fast_tk_get_delta_ns(tkr); + now += __timekeeping_get_ns(tkr); } while (raw_read_seqcount_latch_retry(&tkf->seq, seq)); return now; @@ -565,7 +562,7 @@ static __always_inline u64 __ktime_get_real_fast(struct tk_fast *tkf, u64 *mono) tkr = tkf->base + (seq & 0x01); basem = ktime_to_ns(tkr->base); baser = ktime_to_ns(tkr->base_real); - delta = fast_tk_get_delta_ns(tkr); + delta = __timekeeping_get_ns(tkr); } while (raw_read_seqcount_latch_retry(&tkf->seq, seq)); if (mono) @@ -800,10 +797,15 @@ static void timekeeping_forward_now(struct timekeeper *tk) tk->tkr_mono.cycle_last = cycle_now; tk->tkr_raw.cycle_last = cycle_now; - tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult; - tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult; + while (delta > 0) { + u64 max = tk->tkr_mono.clock->max_cycles; + u64 incr = delta < max ? delta : max; - tk_normalize_xtime(tk); + tk->tkr_mono.xtime_nsec += incr * tk->tkr_mono.mult; + tk->tkr_raw.xtime_nsec += incr * tk->tkr_raw.mult; + tk_normalize_xtime(tk); + delta -= incr; + } } /** diff --git a/kernel/time/vsyscall.c b/kernel/time/vsyscall.c index f0d5062d9cbc..9193d6133e5d 100644 --- a/kernel/time/vsyscall.c +++ b/kernel/time/vsyscall.c @@ -22,10 +22,16 @@ static inline void update_vdso_data(struct vdso_data *vdata, u64 nsec, sec; vdata[CS_HRES_COARSE].cycle_last = tk->tkr_mono.cycle_last; +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT + vdata[CS_HRES_COARSE].max_cycles = tk->tkr_mono.clock->max_cycles; +#endif vdata[CS_HRES_COARSE].mask = tk->tkr_mono.mask; vdata[CS_HRES_COARSE].mult = tk->tkr_mono.mult; vdata[CS_HRES_COARSE].shift = tk->tkr_mono.shift; vdata[CS_RAW].cycle_last = tk->tkr_raw.cycle_last; +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT + vdata[CS_RAW].max_cycles = tk->tkr_raw.clock->max_cycles; +#endif vdata[CS_RAW].mask = tk->tkr_raw.mask; vdata[CS_RAW].mult = tk->tkr_raw.mult; vdata[CS_RAW].shift = tk->tkr_raw.shift; diff --git a/lib/vdso/Kconfig b/lib/vdso/Kconfig index d883ac299508..c46c2300517c 100644 --- a/lib/vdso/Kconfig +++ b/lib/vdso/Kconfig @@ -30,4 +30,11 @@ config GENERIC_VDSO_TIME_NS Selected by architectures which support time namespaces in the VDSO +config GENERIC_VDSO_OVERFLOW_PROTECT + bool + help + Select to add multiplication overflow protection to the VDSO + time getter functions for the price of an extra conditional + in the hotpath. + endif diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c index ce2f69552003..899850bd6f0b 100644 --- a/lib/vdso/gettimeofday.c +++ b/lib/vdso/gettimeofday.c @@ -5,15 +5,23 @@ #include #include -#ifndef vdso_calc_delta -/* - * Default implementation which works for all sane clocksources. That - * obviously excludes x86/TSC. - */ -static __always_inline -u64 vdso_calc_delta(u64 cycles, u64 last, u64 mask, u32 mult) +#ifndef vdso_calc_ns + +#ifdef VDSO_DELTA_NOMASK +# define VDSO_DELTA_MASK(vd) ULLONG_MAX +#else +# define VDSO_DELTA_MASK(vd) (vd->mask) +#endif + +#ifdef CONFIG_GENERIC_VDSO_OVERFLOW_PROTECT +static __always_inline bool vdso_delta_ok(const struct vdso_data *vd, u64 delta) { - return ((cycles - last) & mask) * mult; + return delta < vd->max_cycles; +} +#else +static __always_inline bool vdso_delta_ok(const struct vdso_data *vd, u64 delta) +{ + return true; } #endif @@ -24,6 +32,21 @@ static __always_inline u64 vdso_shift_ns(u64 ns, u32 shift) } #endif +/* + * Default implementation which works for all sane clocksources. That + * obviously excludes x86/TSC. + */ +static __always_inline u64 vdso_calc_ns(const struct vdso_data *vd, u64 cycles, u64 base) +{ + u64 delta = (cycles - vd->cycle_last) & VDSO_DELTA_MASK(vd); + + if (likely(vdso_delta_ok(vd, delta))) + return vdso_shift_ns((delta * vd->mult) + base, vd->shift); + + return mul_u64_u32_add_u64_shr(delta, vd->mult, base, vd->shift); +} +#endif /* vdso_calc_ns */ + #ifndef __arch_vdso_hres_capable static inline bool __arch_vdso_hres_capable(void) { @@ -49,10 +72,10 @@ static inline bool vdso_cycles_ok(u64 cycles) static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_t clk, struct __kernel_timespec *ts) { - const struct vdso_data *vd; const struct timens_offset *offs = &vdns->offset[clk]; const struct vdso_timestamp *vdso_ts; - u64 cycles, last, ns; + const struct vdso_data *vd; + u64 cycles, ns; u32 seq; s64 sec; @@ -73,10 +96,7 @@ static __always_inline int do_hres_timens(const struct vdso_data *vdns, clockid_ cycles = __arch_get_hw_counter(vd->clock_mode, vd); if (unlikely(!vdso_cycles_ok(cycles))) return -1; - ns = vdso_ts->nsec; - last = vd->cycle_last; - ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult); - ns = vdso_shift_ns(ns, vd->shift); + ns = vdso_calc_ns(vd, cycles, vdso_ts->nsec); sec = vdso_ts->sec; } while (unlikely(vdso_read_retry(vd, seq))); @@ -111,7 +131,7 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk, struct __kernel_timespec *ts) { const struct vdso_timestamp *vdso_ts = &vd->basetime[clk]; - u64 cycles, last, sec, ns; + u64 cycles, sec, ns; u32 seq; /* Allows to compile the high resolution parts out */ @@ -144,10 +164,7 @@ static __always_inline int do_hres(const struct vdso_data *vd, clockid_t clk, cycles = __arch_get_hw_counter(vd->clock_mode, vd); if (unlikely(!vdso_cycles_ok(cycles))) return -1; - ns = vdso_ts->nsec; - last = vd->cycle_last; - ns += vdso_calc_delta(cycles, last, vd->mask, vd->mult); - ns = vdso_shift_ns(ns, vd->shift); + ns = vdso_calc_ns(vd, cycles, vdso_ts->nsec); sec = vdso_ts->sec; } while (unlikely(vdso_read_retry(vd, seq))); diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs index 25a896eed468..e3bb5e89f88d 100644 --- a/rust/kernel/time.rs +++ b/rust/kernel/time.rs @@ -4,6 +4,12 @@ //! //! This module contains the kernel APIs related to time and timers that //! have been ported or wrapped for usage by Rust code in the kernel. +//! +//! C header: [`include/linux/jiffies.h`](srctree/include/linux/jiffies.h). +//! C header: [`include/linux/ktime.h`](srctree/include/linux/ktime.h). + +/// The number of nanoseconds per millisecond. +pub const NSEC_PER_MSEC: i64 = bindings::NSEC_PER_MSEC as i64; /// The time unit of Linux kernel. One jiffy equals (1/HZ) second. pub type Jiffies = core::ffi::c_ulong; @@ -18,3 +24,60 @@ pub fn msecs_to_jiffies(msecs: Msecs) -> Jiffies { // matter what the argument is. unsafe { bindings::__msecs_to_jiffies(msecs) } } + +/// A Rust wrapper around a `ktime_t`. +#[repr(transparent)] +#[derive(Copy, Clone)] +pub struct Ktime { + inner: bindings::ktime_t, +} + +impl Ktime { + /// Create a `Ktime` from a raw `ktime_t`. + #[inline] + pub fn from_raw(inner: bindings::ktime_t) -> Self { + Self { inner } + } + + /// Get the current time using `CLOCK_MONOTONIC`. + #[inline] + pub fn ktime_get() -> Self { + // SAFETY: It is always safe to call `ktime_get` outside of NMI context. + Self::from_raw(unsafe { bindings::ktime_get() }) + } + + /// Divide the number of nanoseconds by a compile-time constant. + #[inline] + fn divns_constant(self) -> i64 { + self.to_ns() / DIV + } + + /// Returns the number of nanoseconds. + #[inline] + pub fn to_ns(self) -> i64 { + self.inner + } + + /// Returns the number of milliseconds. + #[inline] + pub fn to_ms(self) -> i64 { + self.divns_constant::() + } +} + +/// Returns the number of milliseconds between two ktimes. +#[inline] +pub fn ktime_ms_delta(later: Ktime, earlier: Ktime) -> i64 { + (later - earlier).to_ms() +} + +impl core::ops::Sub for Ktime { + type Output = Ktime; + + #[inline] + fn sub(self, other: Ktime) -> Ktime { + Self { + inner: self.inner - other.inner, + } + } +}