From 59a93c27c4892f04dfd8f91f8b64d0d6eae43e6e Mon Sep 17 00:00:00 2001 From: Todd Poynor Date: Thu, 9 Aug 2012 00:37:27 -0700 Subject: alarmtimer: Implement minimum alarm interval for allowing suspend alarmtimer suspend return -EBUSY if the next alarm will fire in less than 2 seconds. This allows one RTC seconds tick to occur subsequent to this check before the alarm wakeup time is set, ensuring the wakeup time is still in the future (assuming the RTC does not tick one more second prior to setting the alarm). If suspend is rejected due to an imminent alarm, hold a wakeup source for 2 seconds to process the alarm prior to reattempting suspend. If setting the alarm incurs an -ETIME for an alarm set in the past, or any other problem setting the alarm, abort suspend and hold a wakelock for 1 second while the alarm is allowed to be serviced or other hopefully transient conditions preventing the alarm clear up. Signed-off-by: Todd Poynor Signed-off-by: John Stultz --- kernel/time/alarmtimer.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index aa27d39..54e7145 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -46,6 +46,8 @@ static struct alarm_base { static ktime_t freezer_delta; static DEFINE_SPINLOCK(freezer_delta_lock); +static struct wakeup_source *ws; + #ifdef CONFIG_RTC_CLASS /* rtc timer and device for setting alarm wakeups at suspend */ static struct rtc_timer rtctimer; @@ -250,6 +252,7 @@ static int alarmtimer_suspend(struct device *dev) unsigned long flags; struct rtc_device *rtc; int i; + int ret; spin_lock_irqsave(&freezer_delta_lock, flags); min = freezer_delta; @@ -279,8 +282,10 @@ static int alarmtimer_suspend(struct device *dev) if (min.tv64 == 0) return 0; - /* XXX - Should we enforce a minimum sleep time? */ - WARN_ON(min.tv64 < NSEC_PER_SEC); + if (ktime_to_ns(min) < 2 * NSEC_PER_SEC) { + __pm_wakeup_event(ws, 2 * MSEC_PER_SEC); + return -EBUSY; + } /* Setup an rtc timer to fire that far in the future */ rtc_timer_cancel(rtc, &rtctimer); @@ -288,9 +293,11 @@ static int alarmtimer_suspend(struct device *dev) now = rtc_tm_to_ktime(tm); now = ktime_add(now, min); - rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0)); - - return 0; + /* Set alarm, if in the past reject suspend briefly to handle */ + ret = rtc_timer_start(rtc, &rtctimer, now, ktime_set(0, 0)); + if (ret < 0) + __pm_wakeup_event(ws, MSEC_PER_SEC); + return ret; } #else static int alarmtimer_suspend(struct device *dev) @@ -821,6 +828,7 @@ static int __init alarmtimer_init(void) error = PTR_ERR(pdev); goto out_drv; } + ws = wakeup_source_register("alarmtimer"); return 0; out_drv: -- cgit v1.1 From dae373be9fec6f850159a05af3a1c36236a70d43 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 13 Sep 2012 19:12:16 -0400 Subject: alarmtimer: Use hrtimer per-alarm instead of per-base MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Arve Hjønnevåg reported numerous crashes from the "BUG_ON(timer->state != HRTIMER_STATE_CALLBACK)" check in __run_hrtimer after it called alarmtimer_fired. It ends up the alarmtimer code was not properly handling possible failures of hrtimer_try_to_cancel, and because these faulres occur when the underlying base hrtimer is being run, this limits the ability to properly handle modifications to any alarmtimers on that base. Because much of the logic duplicates the hrtimer logic, it seems that we might as well have a per-alarmtimer hrtimer, and avoid the extra complextity of trying to multiplex many alarmtimers off of one hrtimer. Thus this patch moves the hrtimer to the alarm structure and simplifies the management logic. Changelog: v2: * Includes a fix for double alarm_start calls found by Arve Cc: Arve Hjønnevåg Cc: Colin Cross Cc: Thomas Gleixner Reported-by: Arve Hjønnevåg Tested-by: Arve Hjønnevåg Signed-off-by: John Stultz --- kernel/time/alarmtimer.c | 94 ++++++++++++++---------------------------------- 1 file changed, 27 insertions(+), 67 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 54e7145..b1560eb 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -37,7 +37,6 @@ static struct alarm_base { spinlock_t lock; struct timerqueue_head timerqueue; - struct hrtimer timer; ktime_t (*gettime)(void); clockid_t base_clockid; } alarm_bases[ALARM_NUMTYPE]; @@ -132,21 +131,17 @@ static inline void alarmtimer_rtc_timer_init(void) { } * @base: pointer to the base where the timer is being run * @alarm: pointer to alarm being enqueued. * - * Adds alarm to a alarm_base timerqueue and if necessary sets - * an hrtimer to run. + * Adds alarm to a alarm_base timerqueue * * Must hold base->lock when calling. */ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) { + if (alarm->state & ALARMTIMER_STATE_ENQUEUED) + timerqueue_del(&base->timerqueue, &alarm->node); + timerqueue_add(&base->timerqueue, &alarm->node); alarm->state |= ALARMTIMER_STATE_ENQUEUED; - - if (&alarm->node == timerqueue_getnext(&base->timerqueue)) { - hrtimer_try_to_cancel(&base->timer); - hrtimer_start(&base->timer, alarm->node.expires, - HRTIMER_MODE_ABS); - } } /** @@ -154,28 +149,17 @@ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) * @base: pointer to the base where the timer is running * @alarm: pointer to alarm being removed * - * Removes alarm to a alarm_base timerqueue and if necessary sets - * a new timer to run. + * Removes alarm to a alarm_base timerqueue * * Must hold base->lock when calling. */ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) { - struct timerqueue_node *next = timerqueue_getnext(&base->timerqueue); - if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED)) return; timerqueue_del(&base->timerqueue, &alarm->node); alarm->state &= ~ALARMTIMER_STATE_ENQUEUED; - - if (next == &alarm->node) { - hrtimer_try_to_cancel(&base->timer); - next = timerqueue_getnext(&base->timerqueue); - if (!next) - return; - hrtimer_start(&base->timer, next->expires, HRTIMER_MODE_ABS); - } } @@ -190,42 +174,23 @@ static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) */ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) { - struct alarm_base *base = container_of(timer, struct alarm_base, timer); - struct timerqueue_node *next; + struct alarm *alarm = container_of(timer, struct alarm, timer); + struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; - ktime_t now; int ret = HRTIMER_NORESTART; int restart = ALARMTIMER_NORESTART; spin_lock_irqsave(&base->lock, flags); - now = base->gettime(); - while ((next = timerqueue_getnext(&base->timerqueue))) { - struct alarm *alarm; - ktime_t expired = next->expires; - - if (expired.tv64 > now.tv64) - break; - - alarm = container_of(next, struct alarm, node); - - timerqueue_del(&base->timerqueue, &alarm->node); - alarm->state &= ~ALARMTIMER_STATE_ENQUEUED; - - alarm->state |= ALARMTIMER_STATE_CALLBACK; - spin_unlock_irqrestore(&base->lock, flags); - if (alarm->function) - restart = alarm->function(alarm, now); - spin_lock_irqsave(&base->lock, flags); - alarm->state &= ~ALARMTIMER_STATE_CALLBACK; + alarmtimer_remove(base, alarm); + spin_unlock_irqrestore(&base->lock, flags); - if (restart != ALARMTIMER_NORESTART) { - timerqueue_add(&base->timerqueue, &alarm->node); - alarm->state |= ALARMTIMER_STATE_ENQUEUED; - } - } + if (alarm->function) + restart = alarm->function(alarm, base->gettime()); - if (next) { - hrtimer_set_expires(&base->timer, next->expires); + spin_lock_irqsave(&base->lock, flags); + if (restart != ALARMTIMER_NORESTART) { + hrtimer_set_expires(&alarm->timer, alarm->node.expires); + alarmtimer_enqueue(base, alarm); ret = HRTIMER_RESTART; } spin_unlock_irqrestore(&base->lock, flags); @@ -331,6 +296,9 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, enum alarmtimer_restart (*function)(struct alarm *, ktime_t)) { timerqueue_init(&alarm->node); + hrtimer_init(&alarm->timer, alarm_bases[type].base_clockid, + HRTIMER_MODE_ABS); + alarm->timer.function = alarmtimer_fired; alarm->function = function; alarm->type = type; alarm->state = ALARMTIMER_STATE_INACTIVE; @@ -341,17 +309,19 @@ void alarm_init(struct alarm *alarm, enum alarmtimer_type type, * @alarm: ptr to alarm to set * @start: time to run the alarm */ -void alarm_start(struct alarm *alarm, ktime_t start) +int alarm_start(struct alarm *alarm, ktime_t start) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; + int ret; spin_lock_irqsave(&base->lock, flags); - if (alarmtimer_active(alarm)) - alarmtimer_remove(base, alarm); alarm->node.expires = start; alarmtimer_enqueue(base, alarm); + ret = hrtimer_start(&alarm->timer, alarm->node.expires, + HRTIMER_MODE_ABS); spin_unlock_irqrestore(&base->lock, flags); + return ret; } /** @@ -365,18 +335,12 @@ int alarm_try_to_cancel(struct alarm *alarm) { struct alarm_base *base = &alarm_bases[alarm->type]; unsigned long flags; - int ret = -1; - spin_lock_irqsave(&base->lock, flags); - - if (alarmtimer_callback_running(alarm)) - goto out; + int ret; - if (alarmtimer_is_queued(alarm)) { + spin_lock_irqsave(&base->lock, flags); + ret = hrtimer_try_to_cancel(&alarm->timer); + if (ret >= 0) alarmtimer_remove(base, alarm); - ret = 1; - } else - ret = 0; -out: spin_unlock_irqrestore(&base->lock, flags); return ret; } @@ -809,10 +773,6 @@ static int __init alarmtimer_init(void) for (i = 0; i < ALARM_NUMTYPE; i++) { timerqueue_init_head(&alarm_bases[i].timerqueue); spin_lock_init(&alarm_bases[i].lock); - hrtimer_init(&alarm_bases[i].timer, - alarm_bases[i].base_clockid, - HRTIMER_MODE_ABS); - alarm_bases[i].timer.function = alarmtimer_fired; } error = alarmtimer_rtc_interface_setup(); -- cgit v1.1 From a65bcc12ad74b3efe78847945a1e36cfcbcbc4e6 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Thu, 13 Sep 2012 19:25:22 -0400 Subject: alarmtimer: Rename alarmtimer_remove to alarmtimer_dequeue MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Now that alarmtimer_remove has been simplified, change its name to _dequeue to better match its paired _enqueue function. Cc: Arve Hjønnevåg Cc: Colin Cross Cc: Thomas Gleixner Signed-off-by: John Stultz --- kernel/time/alarmtimer.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index b1560eb..f11d83b 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -145,7 +145,7 @@ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) } /** - * alarmtimer_remove - Removes an alarm timer from an alarm_base timerqueue + * alarmtimer_dequeue - Removes an alarm timer from an alarm_base timerqueue * @base: pointer to the base where the timer is running * @alarm: pointer to alarm being removed * @@ -153,7 +153,7 @@ static void alarmtimer_enqueue(struct alarm_base *base, struct alarm *alarm) * * Must hold base->lock when calling. */ -static void alarmtimer_remove(struct alarm_base *base, struct alarm *alarm) +static void alarmtimer_dequeue(struct alarm_base *base, struct alarm *alarm) { if (!(alarm->state & ALARMTIMER_STATE_ENQUEUED)) return; @@ -181,7 +181,7 @@ static enum hrtimer_restart alarmtimer_fired(struct hrtimer *timer) int restart = ALARMTIMER_NORESTART; spin_lock_irqsave(&base->lock, flags); - alarmtimer_remove(base, alarm); + alarmtimer_dequeue(base, alarm); spin_unlock_irqrestore(&base->lock, flags); if (alarm->function) @@ -340,7 +340,7 @@ int alarm_try_to_cancel(struct alarm *alarm) spin_lock_irqsave(&base->lock, flags); ret = hrtimer_try_to_cancel(&alarm->timer); if (ret >= 0) - alarmtimer_remove(base, alarm); + alarmtimer_dequeue(base, alarm); spin_unlock_irqrestore(&base->lock, flags); return ret; } -- cgit v1.1 From b3c869d35b9b014f63ac0beacd31c57372084d01 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 4 Sep 2012 12:42:27 -0400 Subject: jiffies: Remove compile time assumptions about CLOCK_TICK_RATE CLOCK_TICK_RATE is used to accurately caclulate exactly how a tick will be at a given HZ. This is useful, because while we'd expect NSEC_PER_SEC/HZ, the underlying hardware will have some granularity limit, so we won't be able to have exactly HZ ticks per second. This slight error can cause timekeeping quality problems when using the jiffies or other jiffies driven clocksources. Thus we currently use compile time CLOCK_TICK_RATE value to generate SHIFTED_HZ and NSEC_PER_JIFFIES, which we then use to adjust the jiffies clocksource to correct this error. Unfortunately though, since CLOCK_TICK_RATE is a compile time value, and the jiffies clocksource is registered very early during boot, there are a number of cases where there are different possible hardware timers that have different tick rates. This causes problems in cases like ARM where there are numerous different types of hardware, each having their own compile-time CLOCK_TICK_RATE, making it hard to accurately support different hardware with a single kernel. For the most part, this doesn't matter all that much, as not too many systems actually utilize the jiffies or jiffies driven clocksource. Usually there are other highres clocksources who's granularity error is negligable. Even so, we have some complicated calcualtions that we do everywhere to handle these edge cases. This patch removes the compile time SHIFTED_HZ value, and introduces a register_refined_jiffies() function. This results in the default jiffies clock as being assumed a perfect HZ freq, and allows archtectures that care about jiffies accuracy to call register_refined_jiffies() with the tick rate, specified dynamically at boot. This allows us, where necessary, to not have a compile time CLOCK_TICK_RATE constant, simplifies the jiffies code, and still provides a way to have an accurate jiffies clock. NOTE: Since this patch does not add register_refinied_jiffies() calls for every arch, it may cause time quality regressions in some cases. Its likely these will not be noticable, but if they are an issue, adding the following to the end of setup_arch() should resolve the regression: register_refinied_jiffies(CLOCK_TICK_RATE) Cc: Catalin Marinas Cc: Arnd Bergmann Cc: Richard Cochran Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz --- kernel/time/jiffies.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c index 46da053..6629bf7 100644 --- a/kernel/time/jiffies.c +++ b/kernel/time/jiffies.c @@ -37,7 +37,7 @@ * requested HZ value. It is also not recommended * for "tick-less" systems. */ -#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/SHIFTED_HZ)) +#define NSEC_PER_JIFFY ((NSEC_PER_SEC+HZ/2)/HZ) /* Since jiffies uses a simple NSEC_PER_JIFFY multiplier * conversion, the .shift value could be zero. However @@ -95,3 +95,33 @@ struct clocksource * __init __weak clocksource_default_clock(void) { return &clocksource_jiffies; } + +struct clocksource refined_jiffies; + +int register_refined_jiffies(long cycles_per_second) +{ + u64 nsec_per_tick, shift_hz; + long cycles_per_tick; + + + + refined_jiffies = clocksource_jiffies; + refined_jiffies.name = "refined-jiffies"; + refined_jiffies.rating++; + + /* Calc cycles per tick */ + cycles_per_tick = (cycles_per_second + HZ/2)/HZ; + /* shift_hz stores hz<<8 for extra accuracy */ + shift_hz = (u64)cycles_per_second << 8; + shift_hz += cycles_per_tick/2; + do_div(shift_hz, cycles_per_tick); + /* Calculate nsec_per_tick using shift_hz */ + nsec_per_tick = (u64)NSEC_PER_SEC << 8; + nsec_per_tick += (u32)shift_hz/2; + do_div(nsec_per_tick, (u32)shift_hz); + + refined_jiffies.mult = ((u32)nsec_per_tick) << JIFFIES_SHIFT; + + clocksource_register(&refined_jiffies); + return 0; +} -- cgit v1.1 From d7b4202e0581683f1a14fe598633da0067f5241e Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 4 Sep 2012 15:12:07 -0400 Subject: time: Move timekeeper structure to timekeeper_internal.h for vsyscall changes We're going to need to access the timekeeper in update_vsyscall, so make the structure available for those who need it. Cc: Tony Luck Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Andy Lutomirski Cc: Martin Schwidefsky Cc: Paul Turner Cc: Steven Rostedt Cc: Richard Cochran Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz --- kernel/time/timekeeping.c | 56 +---------------------------------------------- 1 file changed, 1 insertion(+), 55 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index d3b91e7..02c19d3 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -8,6 +8,7 @@ * */ +#include #include #include #include @@ -21,61 +22,6 @@ #include #include -/* Structure holding internal timekeeping values. */ -struct timekeeper { - /* Current clocksource used for timekeeping. */ - struct clocksource *clock; - /* NTP adjusted clock multiplier */ - u32 mult; - /* The shift value of the current clocksource. */ - u32 shift; - /* Number of clock cycles in one NTP interval. */ - cycle_t cycle_interval; - /* Number of clock shifted nano seconds in one NTP interval. */ - u64 xtime_interval; - /* shifted nano seconds left over when rounding cycle_interval */ - s64 xtime_remainder; - /* Raw nano seconds accumulated per NTP interval. */ - u32 raw_interval; - - /* Current CLOCK_REALTIME time in seconds */ - u64 xtime_sec; - /* Clock shifted nano seconds */ - u64 xtime_nsec; - - /* Difference between accumulated time and NTP time in ntp - * shifted nano seconds. */ - s64 ntp_error; - /* Shift conversion between clock shifted nano seconds and - * ntp shifted nano seconds. */ - u32 ntp_error_shift; - - /* - * wall_to_monotonic is what we need to add to xtime (or xtime corrected - * for sub jiffie times) to get to monotonic time. Monotonic is pegged - * at zero at system boot time, so wall_to_monotonic will be negative, - * however, we will ALWAYS keep the tv_nsec part positive so we can use - * the usual normalization. - * - * wall_to_monotonic is moved after resume from suspend for the - * monotonic time not to jump. We need to add total_sleep_time to - * wall_to_monotonic to get the real boot based time offset. - * - * - wall_to_monotonic is no longer the boot time, getboottime must be - * used instead. - */ - struct timespec wall_to_monotonic; - /* Offset clock monotonic -> clock realtime */ - ktime_t offs_real; - /* time spent in suspend */ - struct timespec total_sleep_time; - /* Offset clock monotonic -> clock boottime */ - ktime_t offs_boot; - /* The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock. */ - struct timespec raw_time; - /* Seqlock for all timekeeper values */ - seqlock_t lock; -}; static struct timekeeper timekeeper; -- cgit v1.1 From 706394211648117762edfaeffd6fc04bf3b1a75d Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 4 Sep 2012 15:34:21 -0400 Subject: time: Convert CONFIG_GENERIC_TIME_VSYSCALL to CONFIG_GENERIC_TIME_VSYSCALL_OLD To help migrate archtectures over to the new update_vsyscall method, redfine CONFIG_GENERIC_TIME_VSYSCALL as CONFIG_GENERIC_TIME_VSYSCALL_OLD Cc: Tony Luck Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Andy Lutomirski Cc: Martin Schwidefsky Cc: Paul Turner Cc: Steven Rostedt Cc: Richard Cochran Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz --- kernel/time/Kconfig | 2 +- kernel/time/timekeeping.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index fd42bd4..489c861 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -13,7 +13,7 @@ config ARCH_CLOCKSOURCE_DATA bool # Timekeeping vsyscall support -config GENERIC_TIME_VSYSCALL +config GENERIC_TIME_VSYSCALL_OLD bool # ktime_t scalar 64bit nsec representation diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 02c19d3..7c28513 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -199,7 +199,7 @@ static void timekeeping_update(struct timekeeper *tk, bool clearntp) ntp_clear(); } xt = tk_xtime(tk); - update_vsyscall(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult); + update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult); } /** -- cgit v1.1 From 576094b7f0aaf41aadab9b7d4e5bd85faa432711 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 11 Sep 2012 19:58:13 -0400 Subject: time: Introduce new GENERIC_TIME_VSYSCALL Now that we moved everyone over to GENERIC_TIME_VSYSCALL_OLD, introduce the new declaration and config option for the new update_vsyscall method. Cc: Tony Luck Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Andy Lutomirski Cc: Martin Schwidefsky Cc: Paul Turner Cc: Steven Rostedt Cc: Richard Cochran Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz --- kernel/time/Kconfig | 4 ++++ kernel/time/timekeeping.c | 14 +------------- 2 files changed, 5 insertions(+), 13 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig index 489c861..8601f0d 100644 --- a/kernel/time/Kconfig +++ b/kernel/time/Kconfig @@ -13,6 +13,10 @@ config ARCH_CLOCKSOURCE_DATA bool # Timekeeping vsyscall support +config GENERIC_TIME_VSYSCALL + bool + +# Timekeeping vsyscall support config GENERIC_TIME_VSYSCALL_OLD bool diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 7c28513..ce61801 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -42,15 +42,6 @@ static inline void tk_normalize_xtime(struct timekeeper *tk) } } -static struct timespec tk_xtime(struct timekeeper *tk) -{ - struct timespec ts; - - ts.tv_sec = tk->xtime_sec; - ts.tv_nsec = (long)(tk->xtime_nsec >> tk->shift); - return ts; -} - static void tk_set_xtime(struct timekeeper *tk, const struct timespec *ts) { tk->xtime_sec = ts->tv_sec; @@ -192,14 +183,11 @@ static inline s64 timekeeping_get_ns_raw(struct timekeeper *tk) /* must hold write on timekeeper.lock */ static void timekeeping_update(struct timekeeper *tk, bool clearntp) { - struct timespec xt; - if (clearntp) { tk->ntp_error = 0; ntp_clear(); } - xt = tk_xtime(tk); - update_vsyscall_old(&xt, &tk->wall_to_monotonic, tk->clock, tk->mult); + update_vsyscall(tk); } /** -- cgit v1.1 From 92bb1fcf57a0c2e45f7e67fbf0a8ed475a749236 Mon Sep 17 00:00:00 2001 From: John Stultz Date: Tue, 4 Sep 2012 15:38:12 -0400 Subject: time: Only do nanosecond rounding on GENERIC_TIME_VSYSCALL_OLD systems We only do rounding to the next nanosecond so we don't see minor 1ns inconsistencies in the vsyscall implementations. Since we're changing the vsyscall implementations to avoid this, conditionalize the rounding only to the GENERIC_TIME_VSYSCALL_OLD architectures. Cc: Tony Luck Cc: Paul Mackerras Cc: Benjamin Herrenschmidt Cc: Andy Lutomirski Cc: Martin Schwidefsky Cc: Paul Turner Cc: Steven Rostedt Cc: Richard Cochran Cc: Prarit Bhargava Cc: Thomas Gleixner Signed-off-by: John Stultz --- kernel/time/timekeeping.c | 45 +++++++++++++++++++++++++++++++-------------- 1 file changed, 31 insertions(+), 14 deletions(-) (limited to 'kernel/time') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index ce61801..16280ff 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1062,6 +1062,33 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset, return offset; } +#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD +static inline void old_vsyscall_fixup(struct timekeeper *tk) +{ + s64 remainder; + + /* + * Store only full nanoseconds into xtime_nsec after rounding + * it up and add the remainder to the error difference. + * XXX - This is necessary to avoid small 1ns inconsistnecies caused + * by truncating the remainder in vsyscalls. However, it causes + * additional work to be done in timekeeping_adjust(). Once + * the vsyscall implementations are converted to use xtime_nsec + * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD + * users are removed, this can be killed. + */ + remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1); + tk->xtime_nsec -= remainder; + tk->xtime_nsec += 1ULL << tk->shift; + tk->ntp_error += remainder << tk->ntp_error_shift; + +} +#else +#define old_vsyscall_fixup(tk) +#endif + + + /** * update_wall_time - Uses the current clocksource to increment the wall time * @@ -1073,7 +1100,6 @@ static void update_wall_time(void) cycle_t offset; int shift = 0, maxshift; unsigned long flags; - s64 remainder; write_seqlock_irqsave(&tk->lock, flags); @@ -1115,20 +1141,11 @@ static void update_wall_time(void) /* correct the clock when NTP error is too big */ timekeeping_adjust(tk, offset); - /* - * Store only full nanoseconds into xtime_nsec after rounding - * it up and add the remainder to the error difference. - * XXX - This is necessary to avoid small 1ns inconsistnecies caused - * by truncating the remainder in vsyscalls. However, it causes - * additional work to be done in timekeeping_adjust(). Once - * the vsyscall implementations are converted to use xtime_nsec - * (shifted nanoseconds), this can be killed. - */ - remainder = tk->xtime_nsec & ((1ULL << tk->shift) - 1); - tk->xtime_nsec -= remainder; - tk->xtime_nsec += 1ULL << tk->shift; - tk->ntp_error += remainder << tk->ntp_error_shift; + * XXX This can be killed once everyone converts + * to the new update_vsyscall. + */ + old_vsyscall_fixup(tk); /* * Finally, make sure that after the rounding -- cgit v1.1 From 5b3900cd409466c0070b234d941650685ad0c791 Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Tue, 9 Oct 2012 10:18:23 +0300 Subject: timekeeping: Cast raw_interval to u64 to avoid shift overflow We fixed a bunch of integer overflows in timekeeping code during the 3.6 cycle. I did an audit based on that and found this potential overflow. Signed-off-by: Dan Carpenter Acked-by: John Stultz Link: http://lkml.kernel.org/r/20121009071823.GA19159@elgon.mountain Signed-off-by: Thomas Gleixner Cc: stable@vger.kernel.org --- kernel/time/timekeeping.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/time') diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 16280ff..3eb3fc7c 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -1045,7 +1045,7 @@ static cycle_t logarithmic_accumulation(struct timekeeper *tk, cycle_t offset, accumulate_nsecs_to_secs(tk); /* Accumulate raw time */ - raw_nsecs = tk->raw_interval << shift; + raw_nsecs = (u64)tk->raw_interval << shift; raw_nsecs += tk->raw_time.tv_nsec; if (raw_nsecs >= NSEC_PER_SEC) { u64 raw_secs = raw_nsecs; -- cgit v1.1