diff options
| -rw-r--r-- | include/linux/capability.h | 7 | ||||
| -rw-r--r-- | include/linux/posix-timers.h | 2 | ||||
| -rw-r--r-- | include/linux/time.h | 2 | ||||
| -rw-r--r-- | kernel/time/alarmtimer.c | 330 |
4 files changed, 340 insertions, 1 deletions
diff --git a/include/linux/capability.h b/include/linux/capability.h index 16ee8b49a200..7cb23eae693d 100644 --- a/include/linux/capability.h +++ b/include/linux/capability.h @@ -355,7 +355,12 @@ struct cpu_vfs_cap_data { #define CAP_SYSLOG 34 -#define CAP_LAST_CAP CAP_SYSLOG +/* Allow triggering something that will wake the system */ + +#define CAP_WAKE_ALARM 35 + + +#define CAP_LAST_CAP CAP_WAKE_ALARM #define cap_valid(x) ((x) >= 0 && (x) <= CAP_LAST_CAP) diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index d51243ae0726..808227d40a64 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -5,6 +5,7 @@ #include <linux/list.h> #include <linux/sched.h> #include <linux/timex.h> +#include <linux/alarmtimer.h> union cpu_time_count { cputime_t cpu; @@ -80,6 +81,7 @@ struct k_itimer { unsigned long incr; unsigned long expires; } mmtimer; + struct alarm alarmtimer; } it; }; diff --git a/include/linux/time.h b/include/linux/time.h index 4ea5a75fcacd..b3061782dec3 100644 --- a/include/linux/time.h +++ b/include/linux/time.h @@ -295,6 +295,8 @@ struct itimerval { #define CLOCK_REALTIME_COARSE 5 #define CLOCK_MONOTONIC_COARSE 6 #define CLOCK_BOOTTIME 7 +#define CLOCK_REALTIME_ALARM 8 +#define CLOCK_BOOTTIME_ALARM 9 /* * The IDs of various hardware clocks: diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c index 48c2ee949e61..4058ad79d55f 100644 --- a/kernel/time/alarmtimer.c +++ b/kernel/time/alarmtimer.c @@ -215,6 +215,21 @@ static int alarmtimer_suspend(struct device *dev) } +static void alarmtimer_freezerset(ktime_t absexp, enum alarmtimer_type type) +{ + ktime_t delta; + unsigned long flags; + struct alarm_base *base = &alarm_bases[type]; + + delta = ktime_sub(absexp, base->gettime()); + + spin_lock_irqsave(&freezer_delta_lock, flags); + if (!freezer_delta.tv64 || (delta.tv64 < freezer_delta.tv64)) + freezer_delta = delta; + spin_unlock_irqrestore(&freezer_delta_lock, flags); +} + + /************************************************************************** * alarm kernel interface code */ @@ -279,6 +294,309 @@ void alarm_cancel(struct alarm *alarm) } +/************************************************************************** + * alarm posix interface code + */ + +/* + * clock2alarm - helper that converts from clockid to alarmtypes + * @clockid: clockid. + * + * Helper function that converts from clockids to alarmtypes + */ +static enum alarmtimer_type clock2alarm(clockid_t clockid) +{ + if (clockid == CLOCK_REALTIME_ALARM) + return ALARM_REALTIME; + if (clockid == CLOCK_BOOTTIME_ALARM) + return ALARM_BOOTTIME; + return -1; +} + +/* + * alarm_handle_timer - Callback for posix timers + * @alarm: alarm that fired + * + * Posix timer callback for expired alarm timers. + */ +static void alarm_handle_timer(struct alarm *alarm) +{ + struct k_itimer *ptr = container_of(alarm, struct k_itimer, + it.alarmtimer); + if (posix_timer_event(ptr, 0) != 0) + ptr->it_overrun++; +} + +/* + * alarm_clock_getres - posix getres interface + * @which_clock: clockid + * @tp: timespec to fill + * + * Returns the granularity of underlying alarm base clock + */ +static int alarm_clock_getres(const clockid_t which_clock, struct timespec *tp) +{ + clockid_t baseid = alarm_bases[clock2alarm(which_clock)].base_clockid; + + return hrtimer_get_res(baseid, tp); +} + +/** + * alarm_clock_get - posix clock_get interface + * @which_clock: clockid + * @tp: timespec to fill. + * + * Provides the underlying alarm base time. + */ +static int alarm_clock_get(clockid_t which_clock, struct timespec *tp) +{ + struct alarm_base *base = &alarm_bases[clock2alarm(which_clock)]; + + *tp = ktime_to_timespec(base->gettime()); + return 0; +} + +/** + * alarm_timer_create - posix timer_create interface + * @new_timer: k_itimer pointer to manage + * + * Initializes the k_itimer structure. + */ +static int alarm_timer_create(struct k_itimer *new_timer) +{ + enum alarmtimer_type type; + struct alarm_base *base; + + if (!capable(CAP_WAKE_ALARM)) + return -EPERM; + + type = clock2alarm(new_timer->it_clock); + base = &alarm_bases[type]; + alarm_init(&new_timer->it.alarmtimer, type, alarm_handle_timer); + return 0; +} + +/** + * alarm_timer_get - posix timer_get interface + * @new_timer: k_itimer pointer + * @cur_setting: itimerspec data to fill + * + * Copies the itimerspec data out from the k_itimer + */ +static void alarm_timer_get(struct k_itimer *timr, + struct itimerspec *cur_setting) +{ + cur_setting->it_interval = + ktime_to_timespec(timr->it.alarmtimer.period); + cur_setting->it_value = + ktime_to_timespec(timr->it.alarmtimer.node.expires); + return; +} + +/** + * alarm_timer_del - posix timer_del interface + * @timr: k_itimer pointer to be deleted + * + * Cancels any programmed alarms for the given timer. + */ +static int alarm_timer_del(struct k_itimer *timr) +{ + alarm_cancel(&timr->it.alarmtimer); + return 0; +} + +/** + * alarm_timer_set - posix timer_set interface + * @timr: k_itimer pointer to be deleted + * @flags: timer flags + * @new_setting: itimerspec to be used + * @old_setting: itimerspec being replaced + * + * Sets the timer to new_setting, and starts the timer. + */ +static int alarm_timer_set(struct k_itimer *timr, int flags, + struct itimerspec *new_setting, + struct itimerspec *old_setting) +{ + /* Save old values */ + old_setting->it_interval = + ktime_to_timespec(timr->it.alarmtimer.period); + old_setting->it_value = + ktime_to_timespec(timr->it.alarmtimer.node.expires); + + /* If the timer was already set, cancel it */ + alarm_cancel(&timr->it.alarmtimer); + + /* start the timer */ + alarm_start(&timr->it.alarmtimer, + timespec_to_ktime(new_setting->it_value), + timespec_to_ktime(new_setting->it_interval)); + return 0; +} + +/** + * alarmtimer_nsleep_wakeup - Wakeup function for alarm_timer_nsleep + * @alarm: ptr to alarm that fired + * + * Wakes up the task that set the alarmtimer + */ +static void alarmtimer_nsleep_wakeup(struct alarm *alarm) +{ + struct task_struct *task = (struct task_struct *)alarm->data; + + alarm->data = NULL; + if (task) + wake_up_process(task); +} + +/** + * alarmtimer_do_nsleep - Internal alarmtimer nsleep implementation + * @alarm: ptr to alarmtimer + * @absexp: absolute expiration time + * + * Sets the alarm timer and sleeps until it is fired or interrupted. + */ +static int alarmtimer_do_nsleep(struct alarm *alarm, ktime_t absexp) +{ + alarm->data = (void *)current; + do { + set_current_state(TASK_INTERRUPTIBLE); + alarm_start(alarm, absexp, ktime_set(0, 0)); + if (likely(alarm->data)) + schedule(); + + alarm_cancel(alarm); + } while (alarm->data && !signal_pending(current)); + + __set_current_state(TASK_RUNNING); + + return (alarm->data == NULL); +} + + +/** + * update_rmtp - Update remaining timespec value + * @exp: expiration time + * @type: timer type + * @rmtp: user pointer to remaining timepsec value + * + * Helper function that fills in rmtp value with time between + * now and the exp value + */ +static int update_rmtp(ktime_t exp, enum alarmtimer_type type, + struct timespec __user *rmtp) +{ + struct timespec rmt; + ktime_t rem; + + rem = ktime_sub(exp, alarm_bases[type].gettime()); + + if (rem.tv64 <= 0) + return 0; + rmt = ktime_to_timespec(rem); + + if (copy_to_user(rmtp, &rmt, sizeof(*rmtp))) + return -EFAULT; + + return 1; + +} + +/** + * alarm_timer_nsleep_restart - restartblock alarmtimer nsleep + * @restart: ptr to restart block + * + * Handles restarted clock_nanosleep calls + */ +static long __sched alarm_timer_nsleep_restart(struct restart_block *restart) +{ + enum alarmtimer_type type = restart->nanosleep.index; + ktime_t exp; + struct timespec __user *rmtp; + struct alarm alarm; + int ret = 0; + + exp.tv64 = restart->nanosleep.expires; + alarm_init(&alarm, type, alarmtimer_nsleep_wakeup); + + if (alarmtimer_do_nsleep(&alarm, exp)) + goto out; + + if (freezing(current)) + alarmtimer_freezerset(exp, type); + + rmtp = restart->nanosleep.rmtp; + if (rmtp) { + ret = update_rmtp(exp, type, rmtp); + if (ret <= 0) + goto out; + } + + + /* The other values in restart are already filled in */ + ret = -ERESTART_RESTARTBLOCK; +out: + return ret; +} + +/** + * alarm_timer_nsleep - alarmtimer nanosleep + * @which_clock: clockid + * @flags: determins abstime or relative + * @tsreq: requested sleep time (abs or rel) + * @rmtp: remaining sleep time saved + * + * Handles clock_nanosleep calls against _ALARM clockids + */ +static int alarm_timer_nsleep(const clockid_t which_clock, int flags, + struct timespec *tsreq, struct timespec __user *rmtp) +{ + enum alarmtimer_type type = clock2alarm(which_clock); + struct alarm alarm; + ktime_t exp; + int ret = 0; + struct restart_block *restart; + + if (!capable(CAP_WAKE_ALARM)) + return -EPERM; + + alarm_init(&alarm, type, alarmtimer_nsleep_wakeup); + + exp = timespec_to_ktime(*tsreq); + /* Convert (if necessary) to absolute time */ + if (flags != TIMER_ABSTIME) { + ktime_t now = alarm_bases[type].gettime(); + exp = ktime_add(now, exp); + } + + if (alarmtimer_do_nsleep(&alarm, exp)) + goto out; + + if (freezing(current)) + alarmtimer_freezerset(exp, type); + + /* abs timers don't set remaining time or restart */ + if (flags == TIMER_ABSTIME) { + ret = -ERESTARTNOHAND; + goto out; + } + + if (rmtp) { + ret = update_rmtp(exp, type, rmtp); + if (ret <= 0) + goto out; + } + + restart = ¤t_thread_info()->restart_block; + restart->fn = alarm_timer_nsleep_restart; + restart->nanosleep.index = type; + restart->nanosleep.expires = exp.tv64; + restart->nanosleep.rmtp = rmtp; + ret = -ERESTART_RESTARTBLOCK; + +out: + return ret; +} /************************************************************************** * alarmtimer initialization code @@ -306,6 +624,18 @@ static int __init alarmtimer_init(void) { int error = 0; int i; + struct k_clock alarm_clock = { + .clock_getres = alarm_clock_getres, + .clock_get = alarm_clock_get, + .timer_create = alarm_timer_create, + .timer_set = alarm_timer_set, + .timer_del = alarm_timer_del, + .timer_get = alarm_timer_get, + .nsleep = alarm_timer_nsleep, + }; + + posix_timers_register_clock(CLOCK_REALTIME_ALARM, &alarm_clock); + posix_timers_register_clock(CLOCK_BOOTTIME_ALARM, &alarm_clock); /* Initialize alarm bases */ alarm_bases[ALARM_REALTIME].base_clockid = CLOCK_REALTIME; |