ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/kernel/time/posix-cpu-timers.c b/marvell/linux/kernel/time/posix-cpu-timers.c
new file mode 100644
index 0000000..eacb0ca
--- /dev/null
+++ b/marvell/linux/kernel/time/posix-cpu-timers.c
@@ -0,0 +1,1416 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Implement CPU time clocks for the POSIX clock interface.
+ */
+
+#include <linux/sched/signal.h>
+#include <linux/sched/cputime.h>
+#include <linux/posix-timers.h>
+#include <linux/errno.h>
+#include <linux/math64.h>
+#include <linux/uaccess.h>
+#include <linux/kernel_stat.h>
+#include <trace/events/timer.h>
+#include <linux/tick.h>
+#include <linux/workqueue.h>
+#include <linux/compat.h>
+#include <linux/sched/deadline.h>
+
+#include "posix-timers.h"
+
+static void posix_cpu_timer_rearm(struct k_itimer *timer);
+
+void posix_cputimers_group_init(struct posix_cputimers *pct, u64 cpu_limit)
+{
+ posix_cputimers_init(pct);
+ if (cpu_limit != RLIM_INFINITY) {
+ pct->bases[CPUCLOCK_PROF].nextevt = cpu_limit * NSEC_PER_SEC;
+ pct->timers_active = true;
+ }
+}
+
+/*
+ * Called after updating RLIMIT_CPU to run cpu timer and update
+ * tsk->signal->posix_cputimers.bases[clock].nextevt expiration cache if
+ * necessary. Needs siglock protection since other code may update the
+ * expiration cache as well.
+ */
+void update_rlimit_cpu(struct task_struct *task, unsigned long rlim_new)
+{
+ u64 nsecs = rlim_new * NSEC_PER_SEC;
+
+ spin_lock_irq(&task->sighand->siglock);
+ set_process_cpu_timer(task, CPUCLOCK_PROF, &nsecs, NULL);
+ spin_unlock_irq(&task->sighand->siglock);
+}
+
+/*
+ * Functions for validating access to tasks.
+ */
+static struct task_struct *lookup_task(const pid_t pid, bool thread,
+ bool gettime)
+{
+ struct task_struct *p;
+
+ /*
+ * If the encoded PID is 0, then the timer is targeted at current
+ * or the process to which current belongs.
+ */
+ if (!pid)
+ return thread ? current : current->group_leader;
+
+ p = find_task_by_vpid(pid);
+ if (!p)
+ return p;
+
+ if (thread)
+ return same_thread_group(p, current) ? p : NULL;
+
+ if (gettime) {
+ /*
+ * For clock_gettime(PROCESS) the task does not need to be
+ * the actual group leader. tsk->sighand gives
+ * access to the group's clock.
+ *
+ * Timers need the group leader because they take a
+ * reference on it and store the task pointer until the
+ * timer is destroyed.
+ */
+ return (p == current || thread_group_leader(p)) ? p : NULL;
+ }
+
+ /*
+ * For processes require that p is group leader.
+ */
+ return has_group_leader_pid(p) ? p : NULL;
+}
+
+static struct task_struct *__get_task_for_clock(const clockid_t clock,
+ bool getref, bool gettime)
+{
+ const bool thread = !!CPUCLOCK_PERTHREAD(clock);
+ const pid_t pid = CPUCLOCK_PID(clock);
+ struct task_struct *p;
+
+ if (CPUCLOCK_WHICH(clock) >= CPUCLOCK_MAX)
+ return NULL;
+
+ rcu_read_lock();
+ p = lookup_task(pid, thread, gettime);
+ if (p && getref)
+ get_task_struct(p);
+ rcu_read_unlock();
+ return p;
+}
+
+static inline struct task_struct *get_task_for_clock(const clockid_t clock)
+{
+ return __get_task_for_clock(clock, true, false);
+}
+
+static inline struct task_struct *get_task_for_clock_get(const clockid_t clock)
+{
+ return __get_task_for_clock(clock, true, true);
+}
+
+static inline int validate_clock_permissions(const clockid_t clock)
+{
+ return __get_task_for_clock(clock, false, false) ? 0 : -EINVAL;
+}
+
+/*
+ * Update expiry time from increment, and increase overrun count,
+ * given the current clock sample.
+ */
+static u64 bump_cpu_timer(struct k_itimer *timer, u64 now)
+{
+ u64 delta, incr, expires = timer->it.cpu.node.expires;
+ int i;
+
+ if (!timer->it_interval)
+ return expires;
+
+ if (now < expires)
+ return expires;
+
+ incr = timer->it_interval;
+ delta = now + incr - expires;
+
+ /* Don't use (incr*2 < delta), incr*2 might overflow. */
+ for (i = 0; incr < delta - incr; i++)
+ incr = incr << 1;
+
+ for (; i >= 0; incr >>= 1, i--) {
+ if (delta < incr)
+ continue;
+
+ timer->it.cpu.node.expires += incr;
+ timer->it_overrun += 1LL << i;
+ delta -= incr;
+ }
+ return timer->it.cpu.node.expires;
+}
+
+/* Check whether all cache entries contain U64_MAX, i.e. eternal expiry time */
+static inline bool expiry_cache_is_inactive(const struct posix_cputimers *pct)
+{
+ return !(~pct->bases[CPUCLOCK_PROF].nextevt |
+ ~pct->bases[CPUCLOCK_VIRT].nextevt |
+ ~pct->bases[CPUCLOCK_SCHED].nextevt);
+}
+
+static int
+posix_cpu_clock_getres(const clockid_t which_clock, struct timespec64 *tp)
+{
+ int error = validate_clock_permissions(which_clock);
+
+ if (!error) {
+ tp->tv_sec = 0;
+ tp->tv_nsec = ((NSEC_PER_SEC + HZ - 1) / HZ);
+ if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
+ /*
+ * If sched_clock is using a cycle counter, we
+ * don't have any idea of its true resolution
+ * exported, but it is much more than 1s/HZ.
+ */
+ tp->tv_nsec = 1;
+ }
+ }
+ return error;
+}
+
+static int
+posix_cpu_clock_set(const clockid_t clock, const struct timespec64 *tp)
+{
+ int error = validate_clock_permissions(clock);
+
+ /*
+ * You can never reset a CPU clock, but we check for other errors
+ * in the call before failing with EPERM.
+ */
+ return error ? : -EPERM;
+}
+
+/*
+ * Sample a per-thread clock for the given task. clkid is validated.
+ */
+static u64 cpu_clock_sample(const clockid_t clkid, struct task_struct *p)
+{
+ u64 utime, stime;
+
+ if (clkid == CPUCLOCK_SCHED)
+ return task_sched_runtime(p);
+
+ task_cputime(p, &utime, &stime);
+
+ switch (clkid) {
+ case CPUCLOCK_PROF:
+ return utime + stime;
+ case CPUCLOCK_VIRT:
+ return utime;
+ default:
+ WARN_ON_ONCE(1);
+ }
+ return 0;
+}
+
+static inline void store_samples(u64 *samples, u64 stime, u64 utime, u64 rtime)
+{
+ samples[CPUCLOCK_PROF] = stime + utime;
+ samples[CPUCLOCK_VIRT] = utime;
+ samples[CPUCLOCK_SCHED] = rtime;
+}
+
+static void task_sample_cputime(struct task_struct *p, u64 *samples)
+{
+ u64 stime, utime;
+
+ task_cputime(p, &utime, &stime);
+ store_samples(samples, stime, utime, p->se.sum_exec_runtime);
+}
+
+static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
+ u64 *samples)
+{
+ u64 stime, utime, rtime;
+
+ utime = atomic64_read(&at->utime);
+ stime = atomic64_read(&at->stime);
+ rtime = atomic64_read(&at->sum_exec_runtime);
+ store_samples(samples, stime, utime, rtime);
+}
+
+/*
+ * Set cputime to sum_cputime if sum_cputime > cputime. Use cmpxchg
+ * to avoid race conditions with concurrent updates to cputime.
+ */
+static inline void __update_gt_cputime(atomic64_t *cputime, u64 sum_cputime)
+{
+ u64 curr_cputime;
+retry:
+ curr_cputime = atomic64_read(cputime);
+ if (sum_cputime > curr_cputime) {
+ if (atomic64_cmpxchg(cputime, curr_cputime, sum_cputime) != curr_cputime)
+ goto retry;
+ }
+}
+
+static void update_gt_cputime(struct task_cputime_atomic *cputime_atomic,
+ struct task_cputime *sum)
+{
+ __update_gt_cputime(&cputime_atomic->utime, sum->utime);
+ __update_gt_cputime(&cputime_atomic->stime, sum->stime);
+ __update_gt_cputime(&cputime_atomic->sum_exec_runtime, sum->sum_exec_runtime);
+}
+
+/**
+ * thread_group_sample_cputime - Sample cputime for a given task
+ * @tsk: Task for which cputime needs to be started
+ * @samples: Storage for time samples
+ *
+ * Called from sys_getitimer() to calculate the expiry time of an active
+ * timer. That means group cputime accounting is already active. Called
+ * with task sighand lock held.
+ *
+ * Updates @times with an uptodate sample of the thread group cputimes.
+ */
+void thread_group_sample_cputime(struct task_struct *tsk, u64 *samples)
+{
+ struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+ struct posix_cputimers *pct = &tsk->signal->posix_cputimers;
+
+ WARN_ON_ONCE(!pct->timers_active);
+
+ proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples);
+}
+
+/**
+ * thread_group_start_cputime - Start cputime and return a sample
+ * @tsk: Task for which cputime needs to be started
+ * @samples: Storage for time samples
+ *
+ * The thread group cputime accouting is avoided when there are no posix
+ * CPU timers armed. Before starting a timer it's required to check whether
+ * the time accounting is active. If not, a full update of the atomic
+ * accounting store needs to be done and the accounting enabled.
+ *
+ * Updates @times with an uptodate sample of the thread group cputimes.
+ */
+static void thread_group_start_cputime(struct task_struct *tsk, u64 *samples)
+{
+ struct thread_group_cputimer *cputimer = &tsk->signal->cputimer;
+ struct posix_cputimers *pct = &tsk->signal->posix_cputimers;
+
+ /* Check if cputimer isn't running. This is accessed without locking. */
+ if (!READ_ONCE(pct->timers_active)) {
+ struct task_cputime sum;
+
+ /*
+ * The POSIX timer interface allows for absolute time expiry
+ * values through the TIMER_ABSTIME flag, therefore we have
+ * to synchronize the timer to the clock every time we start it.
+ */
+ thread_group_cputime(tsk, &sum);
+ update_gt_cputime(&cputimer->cputime_atomic, &sum);
+
+ /*
+ * We're setting timers_active without a lock. Ensure this
+ * only gets written to in one operation. We set it after
+ * update_gt_cputime() as a small optimization, but
+ * barriers are not required because update_gt_cputime()
+ * can handle concurrent updates.
+ */
+ WRITE_ONCE(pct->timers_active, true);
+ }
+ proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples);
+}
+
+static void __thread_group_cputime(struct task_struct *tsk, u64 *samples)
+{
+ struct task_cputime ct;
+
+ thread_group_cputime(tsk, &ct);
+ store_samples(samples, ct.stime, ct.utime, ct.sum_exec_runtime);
+}
+
+/*
+ * Sample a process (thread group) clock for the given task clkid. If the
+ * group's cputime accounting is already enabled, read the atomic
+ * store. Otherwise a full update is required. Task's sighand lock must be
+ * held to protect the task traversal on a full update. clkid is already
+ * validated.
+ */
+static u64 cpu_clock_sample_group(const clockid_t clkid, struct task_struct *p,
+ bool start)
+{
+ struct thread_group_cputimer *cputimer = &p->signal->cputimer;
+ struct posix_cputimers *pct = &p->signal->posix_cputimers;
+ u64 samples[CPUCLOCK_MAX];
+
+ if (!READ_ONCE(pct->timers_active)) {
+ if (start)
+ thread_group_start_cputime(p, samples);
+ else
+ __thread_group_cputime(p, samples);
+ } else {
+ proc_sample_cputime_atomic(&cputimer->cputime_atomic, samples);
+ }
+
+ return samples[clkid];
+}
+
+static int posix_cpu_clock_get(const clockid_t clock, struct timespec64 *tp)
+{
+ const clockid_t clkid = CPUCLOCK_WHICH(clock);
+ struct task_struct *tsk;
+ u64 t;
+
+ tsk = get_task_for_clock_get(clock);
+ if (!tsk)
+ return -EINVAL;
+
+ if (CPUCLOCK_PERTHREAD(clock))
+ t = cpu_clock_sample(clkid, tsk);
+ else
+ t = cpu_clock_sample_group(clkid, tsk, false);
+ put_task_struct(tsk);
+
+ *tp = ns_to_timespec64(t);
+ return 0;
+}
+
+/*
+ * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
+ * This is called from sys_timer_create() and do_cpu_nanosleep() with the
+ * new timer already all-zeros initialized.
+ */
+static int posix_cpu_timer_create(struct k_itimer *new_timer)
+{
+ struct task_struct *p = get_task_for_clock(new_timer->it_clock);
+
+ if (!p)
+ return -EINVAL;
+
+ new_timer->kclock = &clock_posix_cpu;
+ timerqueue_init(&new_timer->it.cpu.node);
+ new_timer->it.cpu.task = p;
+ return 0;
+}
+
+/*
+ * Clean up a CPU-clock timer that is about to be destroyed.
+ * This is called from timer deletion with the timer already locked.
+ * If we return TIMER_RETRY, it's necessary to release the timer's lock
+ * and try again. (This happens when the timer is in the middle of firing.)
+ */
+static int posix_cpu_timer_del(struct k_itimer *timer)
+{
+ struct cpu_timer *ctmr = &timer->it.cpu;
+ struct task_struct *p = ctmr->task;
+ struct sighand_struct *sighand;
+ unsigned long flags;
+ int ret = 0;
+
+ if (WARN_ON_ONCE(!p))
+ return -EINVAL;
+
+ /*
+ * Protect against sighand release/switch in exit/exec and process/
+ * thread timer list entry concurrent read/writes.
+ */
+ sighand = lock_task_sighand(p, &flags);
+ if (unlikely(sighand == NULL)) {
+ /*
+ * This raced with the reaping of the task. The exit cleanup
+ * should have removed this timer from the timer queue.
+ */
+ WARN_ON_ONCE(ctmr->head || timerqueue_node_queued(&ctmr->node));
+ } else {
+ if (timer->it.cpu.firing)
+ ret = TIMER_RETRY;
+ else
+ cpu_timer_dequeue(ctmr);
+
+ unlock_task_sighand(p, &flags);
+ }
+
+ if (!ret)
+ put_task_struct(p);
+
+ return ret;
+}
+
+static void cleanup_timerqueue(struct timerqueue_head *head)
+{
+ struct timerqueue_node *node;
+ struct cpu_timer *ctmr;
+
+ while ((node = timerqueue_getnext(head))) {
+ timerqueue_del(head, node);
+ ctmr = container_of(node, struct cpu_timer, node);
+ ctmr->head = NULL;
+ }
+}
+
+/*
+ * Clean out CPU timers which are still armed when a thread exits. The
+ * timers are only removed from the list. No other updates are done. The
+ * corresponding posix timers are still accessible, but cannot be rearmed.
+ *
+ * This must be called with the siglock held.
+ */
+static void cleanup_timers(struct posix_cputimers *pct)
+{
+ cleanup_timerqueue(&pct->bases[CPUCLOCK_PROF].tqhead);
+ cleanup_timerqueue(&pct->bases[CPUCLOCK_VIRT].tqhead);
+ cleanup_timerqueue(&pct->bases[CPUCLOCK_SCHED].tqhead);
+}
+
+/*
+ * These are both called with the siglock held, when the current thread
+ * is being reaped. When the final (leader) thread in the group is reaped,
+ * posix_cpu_timers_exit_group will be called after posix_cpu_timers_exit.
+ */
+void posix_cpu_timers_exit(struct task_struct *tsk)
+{
+ cleanup_timers(&tsk->posix_cputimers);
+}
+void posix_cpu_timers_exit_group(struct task_struct *tsk)
+{
+ cleanup_timers(&tsk->signal->posix_cputimers);
+}
+
+/*
+ * Insert the timer on the appropriate list before any timers that
+ * expire later. This must be called with the sighand lock held.
+ */
+static void arm_timer(struct k_itimer *timer)
+{
+ int clkidx = CPUCLOCK_WHICH(timer->it_clock);
+ struct cpu_timer *ctmr = &timer->it.cpu;
+ u64 newexp = cpu_timer_getexpires(ctmr);
+ struct task_struct *p = ctmr->task;
+ struct posix_cputimer_base *base;
+
+ if (CPUCLOCK_PERTHREAD(timer->it_clock))
+ base = p->posix_cputimers.bases + clkidx;
+ else
+ base = p->signal->posix_cputimers.bases + clkidx;
+
+ if (!cpu_timer_enqueue(&base->tqhead, ctmr))
+ return;
+
+ /*
+ * We are the new earliest-expiring POSIX 1.b timer, hence
+ * need to update expiration cache. Take into account that
+ * for process timers we share expiration cache with itimers
+ * and RLIMIT_CPU and for thread timers with RLIMIT_RTTIME.
+ */
+ if (newexp < base->nextevt)
+ base->nextevt = newexp;
+
+ if (CPUCLOCK_PERTHREAD(timer->it_clock))
+ tick_dep_set_task(p, TICK_DEP_BIT_POSIX_TIMER);
+ else
+ tick_dep_set_signal(p->signal, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+/*
+ * The timer is locked, fire it and arrange for its reload.
+ */
+static void cpu_timer_fire(struct k_itimer *timer)
+{
+ struct cpu_timer *ctmr = &timer->it.cpu;
+
+ if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
+ /*
+ * User don't want any signal.
+ */
+ cpu_timer_setexpires(ctmr, 0);
+ } else if (unlikely(timer->sigq == NULL)) {
+ /*
+ * This a special case for clock_nanosleep,
+ * not a normal timer from sys_timer_create.
+ */
+ wake_up_process(timer->it_process);
+ cpu_timer_setexpires(ctmr, 0);
+ } else if (!timer->it_interval) {
+ /*
+ * One-shot timer. Clear it as soon as it's fired.
+ */
+ posix_timer_event(timer, 0);
+ cpu_timer_setexpires(ctmr, 0);
+ } else if (posix_timer_event(timer, ++timer->it_requeue_pending)) {
+ /*
+ * The signal did not get queued because the signal
+ * was ignored, so we won't get any callback to
+ * reload the timer. But we need to keep it
+ * ticking in case the signal is deliverable next time.
+ */
+ posix_cpu_timer_rearm(timer);
+ ++timer->it_requeue_pending;
+ }
+}
+
+/*
+ * Guts of sys_timer_settime for CPU timers.
+ * This is called with the timer locked and interrupts disabled.
+ * If we return TIMER_RETRY, it's necessary to release the timer's lock
+ * and try again. (This happens when the timer is in the middle of firing.)
+ */
+static int posix_cpu_timer_set(struct k_itimer *timer, int timer_flags,
+ struct itimerspec64 *new, struct itimerspec64 *old)
+{
+ clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
+ u64 old_expires, new_expires, old_incr, val;
+ struct cpu_timer *ctmr = &timer->it.cpu;
+ struct task_struct *p = ctmr->task;
+ struct sighand_struct *sighand;
+ unsigned long flags;
+ int ret = 0;
+
+ if (WARN_ON_ONCE(!p))
+ return -EINVAL;
+
+ /*
+ * Use the to_ktime conversion because that clamps the maximum
+ * value to KTIME_MAX and avoid multiplication overflows.
+ */
+ new_expires = ktime_to_ns(timespec64_to_ktime(new->it_value));
+
+ /*
+ * Protect against sighand release/switch in exit/exec and p->cpu_timers
+ * and p->signal->cpu_timers read/write in arm_timer()
+ */
+ sighand = lock_task_sighand(p, &flags);
+ /*
+ * If p has just been reaped, we can no
+ * longer get any information about it at all.
+ */
+ if (unlikely(sighand == NULL))
+ return -ESRCH;
+
+ /*
+ * Disarm any old timer after extracting its expiry time.
+ */
+ old_incr = timer->it_interval;
+ old_expires = cpu_timer_getexpires(ctmr);
+
+ if (unlikely(timer->it.cpu.firing)) {
+ timer->it.cpu.firing = -1;
+ ret = TIMER_RETRY;
+ } else {
+ cpu_timer_dequeue(ctmr);
+ }
+
+ /*
+ * We need to sample the current value to convert the new
+ * value from to relative and absolute, and to convert the
+ * old value from absolute to relative. To set a process
+ * timer, we need a sample to balance the thread expiry
+ * times (in arm_timer). With an absolute time, we must
+ * check if it's already passed. In short, we need a sample.
+ */
+ if (CPUCLOCK_PERTHREAD(timer->it_clock))
+ val = cpu_clock_sample(clkid, p);
+ else
+ val = cpu_clock_sample_group(clkid, p, true);
+
+ if (old) {
+ if (old_expires == 0) {
+ old->it_value.tv_sec = 0;
+ old->it_value.tv_nsec = 0;
+ } else {
+ /*
+ * Update the timer in case it has overrun already.
+ * If it has, we'll report it as having overrun and
+ * with the next reloaded timer already ticking,
+ * though we are swallowing that pending
+ * notification here to install the new setting.
+ */
+ u64 exp = bump_cpu_timer(timer, val);
+
+ if (val < exp) {
+ old_expires = exp - val;
+ old->it_value = ns_to_timespec64(old_expires);
+ } else {
+ old->it_value.tv_nsec = 1;
+ old->it_value.tv_sec = 0;
+ }
+ }
+ }
+
+ if (unlikely(ret)) {
+ /*
+ * We are colliding with the timer actually firing.
+ * Punt after filling in the timer's old value, and
+ * disable this firing since we are already reporting
+ * it as an overrun (thanks to bump_cpu_timer above).
+ */
+ unlock_task_sighand(p, &flags);
+ goto out;
+ }
+
+ if (new_expires != 0 && !(timer_flags & TIMER_ABSTIME)) {
+ new_expires += val;
+ }
+
+ /*
+ * Install the new expiry time (or zero).
+ * For a timer with no notification action, we don't actually
+ * arm the timer (we'll just fake it for timer_gettime).
+ */
+ cpu_timer_setexpires(ctmr, new_expires);
+ if (new_expires != 0 && val < new_expires) {
+ arm_timer(timer);
+ }
+
+ unlock_task_sighand(p, &flags);
+ /*
+ * Install the new reload setting, and
+ * set up the signal and overrun bookkeeping.
+ */
+ timer->it_interval = timespec64_to_ktime(new->it_interval);
+
+ /*
+ * This acts as a modification timestamp for the timer,
+ * so any automatic reload attempt will punt on seeing
+ * that we have reset the timer manually.
+ */
+ timer->it_requeue_pending = (timer->it_requeue_pending + 2) &
+ ~REQUEUE_PENDING;
+ timer->it_overrun_last = 0;
+ timer->it_overrun = -1;
+
+ if (new_expires != 0 && !(val < new_expires)) {
+ /*
+ * The designated time already passed, so we notify
+ * immediately, even if the thread never runs to
+ * accumulate more time on this clock.
+ */
+ cpu_timer_fire(timer);
+ }
+
+ ret = 0;
+ out:
+ if (old)
+ old->it_interval = ns_to_timespec64(old_incr);
+
+ return ret;
+}
+
+static void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec64 *itp)
+{
+ clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
+ struct cpu_timer *ctmr = &timer->it.cpu;
+ u64 now, expires = cpu_timer_getexpires(ctmr);
+ struct task_struct *p = ctmr->task;
+
+ if (WARN_ON_ONCE(!p))
+ return;
+
+ /*
+ * Easy part: convert the reload time.
+ */
+ itp->it_interval = ktime_to_timespec64(timer->it_interval);
+
+ if (!expires)
+ return;
+
+ /*
+ * Sample the clock to take the difference with the expiry time.
+ */
+ if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
+ now = cpu_clock_sample(clkid, p);
+ } else {
+ struct sighand_struct *sighand;
+ unsigned long flags;
+
+ /*
+ * Protect against sighand release/switch in exit/exec and
+ * also make timer sampling safe if it ends up calling
+ * thread_group_cputime().
+ */
+ sighand = lock_task_sighand(p, &flags);
+ if (unlikely(sighand == NULL)) {
+ /*
+ * The process has been reaped.
+ * We can't even collect a sample any more.
+ * Disarm the timer, nothing else to do.
+ */
+ cpu_timer_setexpires(ctmr, 0);
+ return;
+ } else {
+ now = cpu_clock_sample_group(clkid, p, false);
+ unlock_task_sighand(p, &flags);
+ }
+ }
+
+ if (now < expires) {
+ itp->it_value = ns_to_timespec64(expires - now);
+ } else {
+ /*
+ * The timer should have expired already, but the firing
+ * hasn't taken place yet. Say it's just about to expire.
+ */
+ itp->it_value.tv_nsec = 1;
+ itp->it_value.tv_sec = 0;
+ }
+}
+
+#define MAX_COLLECTED 20
+
+static u64 collect_timerqueue(struct timerqueue_head *head,
+ struct list_head *firing, u64 now)
+{
+ struct timerqueue_node *next;
+ int i = 0;
+
+ while ((next = timerqueue_getnext(head))) {
+ struct cpu_timer *ctmr;
+ u64 expires;
+
+ ctmr = container_of(next, struct cpu_timer, node);
+ expires = cpu_timer_getexpires(ctmr);
+ /* Limit the number of timers to expire at once */
+ if (++i == MAX_COLLECTED || now < expires)
+ return expires;
+
+ ctmr->firing = 1;
+ cpu_timer_dequeue(ctmr);
+ list_add_tail(&ctmr->elist, firing);
+ }
+
+ return U64_MAX;
+}
+
+static void collect_posix_cputimers(struct posix_cputimers *pct, u64 *samples,
+ struct list_head *firing)
+{
+ struct posix_cputimer_base *base = pct->bases;
+ int i;
+
+ for (i = 0; i < CPUCLOCK_MAX; i++, base++) {
+ base->nextevt = collect_timerqueue(&base->tqhead, firing,
+ samples[i]);
+ }
+}
+
+static inline void check_dl_overrun(struct task_struct *tsk)
+{
+ if (tsk->dl.dl_overrun) {
+ tsk->dl.dl_overrun = 0;
+ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ }
+}
+
+static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
+{
+ if (time < limit)
+ return false;
+
+ if (print_fatal_signals) {
+ pr_info("%s Watchdog Timeout (%s): %s[%d]\n",
+ rt ? "RT" : "CPU", hard ? "hard" : "soft",
+ current->comm, task_pid_nr(current));
+ }
+ __group_send_sig_info(signo, SEND_SIG_PRIV, current);
+ return true;
+}
+
+/*
+ * Check for any per-thread CPU timers that have fired and move them off
+ * the tsk->cpu_timers[N] list onto the firing list. Here we update the
+ * tsk->it_*_expires values to reflect the remaining thread CPU timers.
+ */
+static void check_thread_timers(struct task_struct *tsk,
+ struct list_head *firing)
+{
+ struct posix_cputimers *pct = &tsk->posix_cputimers;
+ u64 samples[CPUCLOCK_MAX];
+ unsigned long soft;
+
+ if (dl_task(tsk))
+ check_dl_overrun(tsk);
+
+ if (expiry_cache_is_inactive(pct))
+ return;
+
+ task_sample_cputime(tsk, samples);
+ collect_posix_cputimers(pct, samples, firing);
+
+ /*
+ * Check for the special case thread timers.
+ */
+ soft = task_rlimit(tsk, RLIMIT_RTTIME);
+ if (soft != RLIM_INFINITY) {
+ /* Task RT timeout is accounted in jiffies. RTTIME is usec */
+ unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
+ unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
+
+ /* At the hard limit, send SIGKILL. No further action. */
+ if (hard != RLIM_INFINITY &&
+ check_rlimit(rttime, hard, SIGKILL, true, true))
+ return;
+
+ /* At the soft limit, send a SIGXCPU every second */
+ if (check_rlimit(rttime, soft, SIGXCPU, true, false)) {
+ soft += USEC_PER_SEC;
+ tsk->signal->rlim[RLIMIT_RTTIME].rlim_cur = soft;
+ }
+ }
+
+ if (expiry_cache_is_inactive(pct))
+ tick_dep_clear_task(tsk, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+static inline void stop_process_timers(struct signal_struct *sig)
+{
+ struct posix_cputimers *pct = &sig->posix_cputimers;
+
+ /* Turn off the active flag. This is done without locking. */
+ WRITE_ONCE(pct->timers_active, false);
+ tick_dep_clear_signal(sig, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+static void check_cpu_itimer(struct task_struct *tsk, struct cpu_itimer *it,
+ u64 *expires, u64 cur_time, int signo)
+{
+ if (!it->expires)
+ return;
+
+ if (cur_time >= it->expires) {
+ if (it->incr)
+ it->expires += it->incr;
+ else
+ it->expires = 0;
+
+ trace_itimer_expire(signo == SIGPROF ?
+ ITIMER_PROF : ITIMER_VIRTUAL,
+ task_tgid(tsk), cur_time);
+ __group_send_sig_info(signo, SEND_SIG_PRIV, tsk);
+ }
+
+ if (it->expires && it->expires < *expires)
+ *expires = it->expires;
+}
+
+/*
+ * Check for any per-thread CPU timers that have fired and move them
+ * off the tsk->*_timers list onto the firing list. Per-thread timers
+ * have already been taken off.
+ */
+static void check_process_timers(struct task_struct *tsk,
+ struct list_head *firing)
+{
+ struct signal_struct *const sig = tsk->signal;
+ struct posix_cputimers *pct = &sig->posix_cputimers;
+ u64 samples[CPUCLOCK_MAX];
+ unsigned long soft;
+
+ /*
+ * If there are no active process wide timers (POSIX 1.b, itimers,
+ * RLIMIT_CPU) nothing to check. Also skip the process wide timer
+ * processing when there is already another task handling them.
+ */
+ if (!READ_ONCE(pct->timers_active) || pct->expiry_active)
+ return;
+
+ /*
+ * Signify that a thread is checking for process timers.
+ * Write access to this field is protected by the sighand lock.
+ */
+ pct->expiry_active = true;
+
+ /*
+ * Collect the current process totals. Group accounting is active
+ * so the sample can be taken directly.
+ */
+ proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic, samples);
+ collect_posix_cputimers(pct, samples, firing);
+
+ /*
+ * Check for the special case process timers.
+ */
+ check_cpu_itimer(tsk, &sig->it[CPUCLOCK_PROF],
+ &pct->bases[CPUCLOCK_PROF].nextevt,
+ samples[CPUCLOCK_PROF], SIGPROF);
+ check_cpu_itimer(tsk, &sig->it[CPUCLOCK_VIRT],
+ &pct->bases[CPUCLOCK_VIRT].nextevt,
+ samples[CPUCLOCK_VIRT], SIGVTALRM);
+
+ soft = task_rlimit(tsk, RLIMIT_CPU);
+ if (soft != RLIM_INFINITY) {
+ /* RLIMIT_CPU is in seconds. Samples are nanoseconds */
+ unsigned long hard = task_rlimit_max(tsk, RLIMIT_CPU);
+ u64 ptime = samples[CPUCLOCK_PROF];
+ u64 softns = (u64)soft * NSEC_PER_SEC;
+ u64 hardns = (u64)hard * NSEC_PER_SEC;
+
+ /* At the hard limit, send SIGKILL. No further action. */
+ if (hard != RLIM_INFINITY &&
+ check_rlimit(ptime, hardns, SIGKILL, false, true))
+ return;
+
+ /* At the soft limit, send a SIGXCPU every second */
+ if (check_rlimit(ptime, softns, SIGXCPU, false, false)) {
+ sig->rlim[RLIMIT_CPU].rlim_cur = soft + 1;
+ softns += NSEC_PER_SEC;
+ }
+
+ /* Update the expiry cache */
+ if (softns < pct->bases[CPUCLOCK_PROF].nextevt)
+ pct->bases[CPUCLOCK_PROF].nextevt = softns;
+ }
+
+ if (expiry_cache_is_inactive(pct))
+ stop_process_timers(sig);
+
+ pct->expiry_active = false;
+}
+
+/*
+ * This is called from the signal code (via posixtimer_rearm)
+ * when the last timer signal was delivered and we have to reload the timer.
+ */
+static void posix_cpu_timer_rearm(struct k_itimer *timer)
+{
+ clockid_t clkid = CPUCLOCK_WHICH(timer->it_clock);
+ struct cpu_timer *ctmr = &timer->it.cpu;
+ struct task_struct *p = ctmr->task;
+ struct sighand_struct *sighand;
+ unsigned long flags;
+ u64 now;
+
+ if (WARN_ON_ONCE(!p))
+ return;
+
+ /*
+ * Fetch the current sample and update the timer's expiry time.
+ */
+ if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
+ now = cpu_clock_sample(clkid, p);
+ bump_cpu_timer(timer, now);
+ if (unlikely(p->exit_state))
+ return;
+
+ /* Protect timer list r/w in arm_timer() */
+ sighand = lock_task_sighand(p, &flags);
+ if (!sighand)
+ return;
+ } else {
+ /*
+ * Protect arm_timer() and timer sampling in case of call to
+ * thread_group_cputime().
+ */
+ sighand = lock_task_sighand(p, &flags);
+ if (unlikely(sighand == NULL)) {
+ /*
+ * The process has been reaped.
+ * We can't even collect a sample any more.
+ */
+ cpu_timer_setexpires(ctmr, 0);
+ return;
+ } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
+ /* If the process is dying, no need to rearm */
+ goto unlock;
+ }
+ now = cpu_clock_sample_group(clkid, p, true);
+ bump_cpu_timer(timer, now);
+ /* Leave the sighand locked for the call below. */
+ }
+
+ /*
+ * Now re-arm for the new expiry time.
+ */
+ arm_timer(timer);
+unlock:
+ unlock_task_sighand(p, &flags);
+}
+
+/**
+ * task_cputimers_expired - Check whether posix CPU timers are expired
+ *
+ * @samples: Array of current samples for the CPUCLOCK clocks
+ * @pct: Pointer to a posix_cputimers container
+ *
+ * Returns true if any member of @samples is greater than the corresponding
+ * member of @pct->bases[CLK].nextevt. False otherwise
+ */
+static inline bool
+task_cputimers_expired(const u64 *samples, struct posix_cputimers *pct)
+{
+ int i;
+
+ for (i = 0; i < CPUCLOCK_MAX; i++) {
+ if (samples[i] >= pct->bases[i].nextevt)
+ return true;
+ }
+ return false;
+}
+
+/**
+ * fastpath_timer_check - POSIX CPU timers fast path.
+ *
+ * @tsk: The task (thread) being checked.
+ *
+ * Check the task and thread group timers. If both are zero (there are no
+ * timers set) return false. Otherwise snapshot the task and thread group
+ * timers and compare them with the corresponding expiration times. Return
+ * true if a timer has expired, else return false.
+ */
+static inline bool fastpath_timer_check(struct task_struct *tsk)
+{
+ struct posix_cputimers *pct = &tsk->posix_cputimers;
+ struct signal_struct *sig;
+
+ if (!expiry_cache_is_inactive(pct)) {
+ u64 samples[CPUCLOCK_MAX];
+
+ task_sample_cputime(tsk, samples);
+ if (task_cputimers_expired(samples, pct))
+ return true;
+ }
+
+ sig = tsk->signal;
+ pct = &sig->posix_cputimers;
+ /*
+ * Check if thread group timers expired when timers are active and
+ * no other thread in the group is already handling expiry for
+ * thread group cputimers. These fields are read without the
+ * sighand lock. However, this is fine because this is meant to be
+ * a fastpath heuristic to determine whether we should try to
+ * acquire the sighand lock to handle timer expiry.
+ *
+ * In the worst case scenario, if concurrently timers_active is set
+ * or expiry_active is cleared, but the current thread doesn't see
+ * the change yet, the timer checks are delayed until the next
+ * thread in the group gets a scheduler interrupt to handle the
+ * timer. This isn't an issue in practice because these types of
+ * delays with signals actually getting sent are expected.
+ */
+ if (READ_ONCE(pct->timers_active) && !READ_ONCE(pct->expiry_active)) {
+ u64 samples[CPUCLOCK_MAX];
+
+ proc_sample_cputime_atomic(&sig->cputimer.cputime_atomic,
+ samples);
+
+ if (task_cputimers_expired(samples, pct))
+ return true;
+ }
+
+ if (dl_task(tsk) && tsk->dl.dl_overrun)
+ return true;
+
+ return false;
+}
+
+/*
+ * This is called from the timer interrupt handler. The irq handler has
+ * already updated our counts. We need to check if any timers fire now.
+ * Interrupts are disabled.
+ */
+void run_posix_cpu_timers(void)
+{
+ struct task_struct *tsk = current;
+ struct k_itimer *timer, *next;
+ unsigned long flags;
+ LIST_HEAD(firing);
+
+ lockdep_assert_irqs_disabled();
+
+ /*
+ * The fast path checks that there are no expired thread or thread
+ * group timers. If that's so, just return.
+ */
+ if (!fastpath_timer_check(tsk))
+ return;
+
+ if (!lock_task_sighand(tsk, &flags))
+ return;
+ /*
+ * Here we take off tsk->signal->cpu_timers[N] and
+ * tsk->cpu_timers[N] all the timers that are firing, and
+ * put them on the firing list.
+ */
+ check_thread_timers(tsk, &firing);
+
+ check_process_timers(tsk, &firing);
+
+ /*
+ * We must release these locks before taking any timer's lock.
+ * There is a potential race with timer deletion here, as the
+ * siglock now protects our private firing list. We have set
+ * the firing flag in each timer, so that a deletion attempt
+ * that gets the timer lock before we do will give it up and
+ * spin until we've taken care of that timer below.
+ */
+ unlock_task_sighand(tsk, &flags);
+
+ /*
+ * Now that all the timers on our list have the firing flag,
+ * no one will touch their list entries but us. We'll take
+ * each timer's lock before clearing its firing flag, so no
+ * timer call will interfere.
+ */
+ list_for_each_entry_safe(timer, next, &firing, it.cpu.elist) {
+ int cpu_firing;
+
+ spin_lock(&timer->it_lock);
+ list_del_init(&timer->it.cpu.elist);
+ cpu_firing = timer->it.cpu.firing;
+ timer->it.cpu.firing = 0;
+ /*
+ * The firing flag is -1 if we collided with a reset
+ * of the timer, which already reported this
+ * almost-firing as an overrun. So don't generate an event.
+ */
+ if (likely(cpu_firing >= 0))
+ cpu_timer_fire(timer);
+ spin_unlock(&timer->it_lock);
+ }
+}
+
+/*
+ * Set one of the process-wide special case CPU timers or RLIMIT_CPU.
+ * The tsk->sighand->siglock must be held by the caller.
+ */
+void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid,
+ u64 *newval, u64 *oldval)
+{
+ u64 now, *nextevt;
+
+ if (WARN_ON_ONCE(clkid >= CPUCLOCK_SCHED))
+ return;
+
+ nextevt = &tsk->signal->posix_cputimers.bases[clkid].nextevt;
+ now = cpu_clock_sample_group(clkid, tsk, true);
+
+ if (oldval) {
+ /*
+ * We are setting itimer. The *oldval is absolute and we update
+ * it to be relative, *newval argument is relative and we update
+ * it to be absolute.
+ */
+ if (*oldval) {
+ if (*oldval <= now) {
+ /* Just about to fire. */
+ *oldval = TICK_NSEC;
+ } else {
+ *oldval -= now;
+ }
+ }
+
+ if (!*newval)
+ return;
+ *newval += now;
+ }
+
+ /*
+ * Update expiration cache if this is the earliest timer. CPUCLOCK_PROF
+ * expiry cache is also used by RLIMIT_CPU!.
+ */
+ if (*newval < *nextevt)
+ *nextevt = *newval;
+
+ tick_dep_set_signal(tsk->signal, TICK_DEP_BIT_POSIX_TIMER);
+}
+
+static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
+ const struct timespec64 *rqtp)
+{
+ struct itimerspec64 it;
+ struct k_itimer timer;
+ u64 expires;
+ int error;
+
+ /*
+ * Set up a temporary timer and then wait for it to go off.
+ */
+ memset(&timer, 0, sizeof timer);
+ spin_lock_init(&timer.it_lock);
+ timer.it_clock = which_clock;
+ timer.it_overrun = -1;
+ error = posix_cpu_timer_create(&timer);
+ timer.it_process = current;
+
+ if (!error) {
+ static struct itimerspec64 zero_it;
+ struct restart_block *restart;
+
+ memset(&it, 0, sizeof(it));
+ it.it_value = *rqtp;
+
+ spin_lock_irq(&timer.it_lock);
+ error = posix_cpu_timer_set(&timer, flags, &it, NULL);
+ if (error) {
+ spin_unlock_irq(&timer.it_lock);
+ return error;
+ }
+
+ while (!signal_pending(current)) {
+ if (!cpu_timer_getexpires(&timer.it.cpu)) {
+ /*
+ * Our timer fired and was reset, below
+ * deletion can not fail.
+ */
+ posix_cpu_timer_del(&timer);
+ spin_unlock_irq(&timer.it_lock);
+ return 0;
+ }
+
+ /*
+ * Block until cpu_timer_fire (or a signal) wakes us.
+ */
+ __set_current_state(TASK_INTERRUPTIBLE);
+ spin_unlock_irq(&timer.it_lock);
+ schedule();
+ spin_lock_irq(&timer.it_lock);
+ }
+
+ /*
+ * We were interrupted by a signal.
+ */
+ expires = cpu_timer_getexpires(&timer.it.cpu);
+ error = posix_cpu_timer_set(&timer, 0, &zero_it, &it);
+ if (!error) {
+ /*
+ * Timer is now unarmed, deletion can not fail.
+ */
+ posix_cpu_timer_del(&timer);
+ }
+ spin_unlock_irq(&timer.it_lock);
+
+ while (error == TIMER_RETRY) {
+ /*
+ * We need to handle case when timer was or is in the
+ * middle of firing. In other cases we already freed
+ * resources.
+ */
+ spin_lock_irq(&timer.it_lock);
+ error = posix_cpu_timer_del(&timer);
+ spin_unlock_irq(&timer.it_lock);
+ }
+
+ if ((it.it_value.tv_sec | it.it_value.tv_nsec) == 0) {
+ /*
+ * It actually did fire already.
+ */
+ return 0;
+ }
+
+ error = -ERESTART_RESTARTBLOCK;
+ /*
+ * Report back to the user the time still remaining.
+ */
+ restart = ¤t->restart_block;
+ restart->nanosleep.expires = expires;
+ if (restart->nanosleep.type != TT_NONE)
+ error = nanosleep_copyout(restart, &it.it_value);
+ }
+
+ return error;
+}
+
+static long posix_cpu_nsleep_restart(struct restart_block *restart_block);
+
+static int posix_cpu_nsleep(const clockid_t which_clock, int flags,
+ const struct timespec64 *rqtp)
+{
+ struct restart_block *restart_block = ¤t->restart_block;
+ int error;
+
+ /*
+ * Diagnose required errors first.
+ */
+ if (CPUCLOCK_PERTHREAD(which_clock) &&
+ (CPUCLOCK_PID(which_clock) == 0 ||
+ CPUCLOCK_PID(which_clock) == task_pid_vnr(current)))
+ return -EINVAL;
+
+ error = do_cpu_nanosleep(which_clock, flags, rqtp);
+
+ if (error == -ERESTART_RESTARTBLOCK) {
+
+ if (flags & TIMER_ABSTIME)
+ return -ERESTARTNOHAND;
+
+ restart_block->nanosleep.clockid = which_clock;
+ set_restart_fn(restart_block, posix_cpu_nsleep_restart);
+ }
+ return error;
+}
+
+static long posix_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+ clockid_t which_clock = restart_block->nanosleep.clockid;
+ struct timespec64 t;
+
+ t = ns_to_timespec64(restart_block->nanosleep.expires);
+
+ return do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t);
+}
+
+#define PROCESS_CLOCK make_process_cpuclock(0, CPUCLOCK_SCHED)
+#define THREAD_CLOCK make_thread_cpuclock(0, CPUCLOCK_SCHED)
+
+static int process_cpu_clock_getres(const clockid_t which_clock,
+ struct timespec64 *tp)
+{
+ return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
+}
+static int process_cpu_clock_get(const clockid_t which_clock,
+ struct timespec64 *tp)
+{
+ return posix_cpu_clock_get(PROCESS_CLOCK, tp);
+}
+static int process_cpu_timer_create(struct k_itimer *timer)
+{
+ timer->it_clock = PROCESS_CLOCK;
+ return posix_cpu_timer_create(timer);
+}
+static int process_cpu_nsleep(const clockid_t which_clock, int flags,
+ const struct timespec64 *rqtp)
+{
+ return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp);
+}
+static int thread_cpu_clock_getres(const clockid_t which_clock,
+ struct timespec64 *tp)
+{
+ return posix_cpu_clock_getres(THREAD_CLOCK, tp);
+}
+static int thread_cpu_clock_get(const clockid_t which_clock,
+ struct timespec64 *tp)
+{
+ return posix_cpu_clock_get(THREAD_CLOCK, tp);
+}
+static int thread_cpu_timer_create(struct k_itimer *timer)
+{
+ timer->it_clock = THREAD_CLOCK;
+ return posix_cpu_timer_create(timer);
+}
+
+const struct k_clock clock_posix_cpu = {
+ .clock_getres = posix_cpu_clock_getres,
+ .clock_set = posix_cpu_clock_set,
+ .clock_get = posix_cpu_clock_get,
+ .timer_create = posix_cpu_timer_create,
+ .nsleep = posix_cpu_nsleep,
+ .timer_set = posix_cpu_timer_set,
+ .timer_del = posix_cpu_timer_del,
+ .timer_get = posix_cpu_timer_get,
+ .timer_rearm = posix_cpu_timer_rearm,
+};
+
+const struct k_clock clock_process = {
+ .clock_getres = process_cpu_clock_getres,
+ .clock_get = process_cpu_clock_get,
+ .timer_create = process_cpu_timer_create,
+ .nsleep = process_cpu_nsleep,
+};
+
+const struct k_clock clock_thread = {
+ .clock_getres = thread_cpu_clock_getres,
+ .clock_get = thread_cpu_clock_get,
+ .timer_create = thread_cpu_timer_create,
+};