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-rw-r--r--kernel/posix-cpu-timers.c1672
1 files changed, 1672 insertions, 0 deletions
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
new file mode 100644
index 0000000..4e5288a
--- /dev/null
+++ b/kernel/posix-cpu-timers.c
@@ -0,0 +1,1672 @@
+/*
+ * Implement CPU time clocks for the POSIX clock interface.
+ */
+
+#include <linux/sched.h>
+#include <linux/posix-timers.h>
+#include <linux/errno.h>
+#include <linux/math64.h>
+#include <asm/uaccess.h>
+#include <linux/kernel_stat.h>
+
+/*
+ * Allocate the thread_group_cputime structure appropriately and fill in the
+ * current values of the fields. Called from copy_signal() via
+ * thread_group_cputime_clone_thread() when adding a second or subsequent
+ * thread to a thread group. Assumes interrupts are enabled when called.
+ */
+int thread_group_cputime_alloc(struct task_struct *tsk)
+{
+ struct signal_struct *sig = tsk->signal;
+ struct task_cputime *cputime;
+
+ /*
+ * If we have multiple threads and we don't already have a
+ * per-CPU task_cputime struct (checked in the caller), allocate
+ * one and fill it in with the times accumulated so far. We may
+ * race with another thread so recheck after we pick up the sighand
+ * lock.
+ */
+ cputime = alloc_percpu(struct task_cputime);
+ if (cputime == NULL)
+ return -ENOMEM;
+ spin_lock_irq(&tsk->sighand->siglock);
+ if (sig->cputime.totals) {
+ spin_unlock_irq(&tsk->sighand->siglock);
+ free_percpu(cputime);
+ return 0;
+ }
+ sig->cputime.totals = cputime;
+ cputime = per_cpu_ptr(sig->cputime.totals, smp_processor_id());
+ cputime->utime = tsk->utime;
+ cputime->stime = tsk->stime;
+ cputime->sum_exec_runtime = tsk->se.sum_exec_runtime;
+ spin_unlock_irq(&tsk->sighand->siglock);
+ return 0;
+}
+
+/**
+ * thread_group_cputime - Sum the thread group time fields across all CPUs.
+ *
+ * @tsk: The task we use to identify the thread group.
+ * @times: task_cputime structure in which we return the summed fields.
+ *
+ * Walk the list of CPUs to sum the per-CPU time fields in the thread group
+ * time structure.
+ */
+void thread_group_cputime(
+ struct task_struct *tsk,
+ struct task_cputime *times)
+{
+ struct signal_struct *sig;
+ int i;
+ struct task_cputime *tot;
+
+ sig = tsk->signal;
+ if (unlikely(!sig) || !sig->cputime.totals) {
+ times->utime = tsk->utime;
+ times->stime = tsk->stime;
+ times->sum_exec_runtime = tsk->se.sum_exec_runtime;
+ return;
+ }
+ times->stime = times->utime = cputime_zero;
+ times->sum_exec_runtime = 0;
+ for_each_possible_cpu(i) {
+ tot = per_cpu_ptr(tsk->signal->cputime.totals, i);
+ times->utime = cputime_add(times->utime, tot->utime);
+ times->stime = cputime_add(times->stime, tot->stime);
+ times->sum_exec_runtime += tot->sum_exec_runtime;
+ }
+}
+
+/*
+ * Called after updating RLIMIT_CPU to set timer expiration if necessary.
+ */
+void update_rlimit_cpu(unsigned long rlim_new)
+{
+ cputime_t cputime;
+
+ cputime = secs_to_cputime(rlim_new);
+ if (cputime_eq(current->signal->it_prof_expires, cputime_zero) ||
+ cputime_lt(current->signal->it_prof_expires, cputime)) {
+ spin_lock_irq(&current->sighand->siglock);
+ set_process_cpu_timer(current, CPUCLOCK_PROF, &cputime, NULL);
+ spin_unlock_irq(&current->sighand->siglock);
+ }
+}
+
+static int check_clock(const clockid_t which_clock)
+{
+ int error = 0;
+ struct task_struct *p;
+ const pid_t pid = CPUCLOCK_PID(which_clock);
+
+ if (CPUCLOCK_WHICH(which_clock) >= CPUCLOCK_MAX)
+ return -EINVAL;
+
+ if (pid == 0)
+ return 0;
+
+ read_lock(&tasklist_lock);
+ p = find_task_by_vpid(pid);
+ if (!p || !(CPUCLOCK_PERTHREAD(which_clock) ?
+ same_thread_group(p, current) : thread_group_leader(p))) {
+ error = -EINVAL;
+ }
+ read_unlock(&tasklist_lock);
+
+ return error;
+}
+
+static inline union cpu_time_count
+timespec_to_sample(const clockid_t which_clock, const struct timespec *tp)
+{
+ union cpu_time_count ret;
+ ret.sched = 0; /* high half always zero when .cpu used */
+ if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
+ ret.sched = (unsigned long long)tp->tv_sec * NSEC_PER_SEC + tp->tv_nsec;
+ } else {
+ ret.cpu = timespec_to_cputime(tp);
+ }
+ return ret;
+}
+
+static void sample_to_timespec(const clockid_t which_clock,
+ union cpu_time_count cpu,
+ struct timespec *tp)
+{
+ if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED)
+ *tp = ns_to_timespec(cpu.sched);
+ else
+ cputime_to_timespec(cpu.cpu, tp);
+}
+
+static inline int cpu_time_before(const clockid_t which_clock,
+ union cpu_time_count now,
+ union cpu_time_count then)
+{
+ if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
+ return now.sched < then.sched;
+ } else {
+ return cputime_lt(now.cpu, then.cpu);
+ }
+}
+static inline void cpu_time_add(const clockid_t which_clock,
+ union cpu_time_count *acc,
+ union cpu_time_count val)
+{
+ if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
+ acc->sched += val.sched;
+ } else {
+ acc->cpu = cputime_add(acc->cpu, val.cpu);
+ }
+}
+static inline union cpu_time_count cpu_time_sub(const clockid_t which_clock,
+ union cpu_time_count a,
+ union cpu_time_count b)
+{
+ if (CPUCLOCK_WHICH(which_clock) == CPUCLOCK_SCHED) {
+ a.sched -= b.sched;
+ } else {
+ a.cpu = cputime_sub(a.cpu, b.cpu);
+ }
+ return a;
+}
+
+/*
+ * Divide and limit the result to res >= 1
+ *
+ * This is necessary to prevent signal delivery starvation, when the result of
+ * the division would be rounded down to 0.
+ */
+static inline cputime_t cputime_div_non_zero(cputime_t time, unsigned long div)
+{
+ cputime_t res = cputime_div(time, div);
+
+ return max_t(cputime_t, res, 1);
+}
+
+/*
+ * Update expiry time from increment, and increase overrun count,
+ * given the current clock sample.
+ */
+static void bump_cpu_timer(struct k_itimer *timer,
+ union cpu_time_count now)
+{
+ int i;
+
+ if (timer->it.cpu.incr.sched == 0)
+ return;
+
+ if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
+ unsigned long long delta, incr;
+
+ if (now.sched < timer->it.cpu.expires.sched)
+ return;
+ incr = timer->it.cpu.incr.sched;
+ delta = now.sched + incr - timer->it.cpu.expires.sched;
+ /* 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.expires.sched += incr;
+ timer->it_overrun += 1 << i;
+ delta -= incr;
+ }
+ } else {
+ cputime_t delta, incr;
+
+ if (cputime_lt(now.cpu, timer->it.cpu.expires.cpu))
+ return;
+ incr = timer->it.cpu.incr.cpu;
+ delta = cputime_sub(cputime_add(now.cpu, incr),
+ timer->it.cpu.expires.cpu);
+ /* Don't use (incr*2 < delta), incr*2 might overflow. */
+ for (i = 0; cputime_lt(incr, cputime_sub(delta, incr)); i++)
+ incr = cputime_add(incr, incr);
+ for (; i >= 0; incr = cputime_halve(incr), i--) {
+ if (cputime_lt(delta, incr))
+ continue;
+ timer->it.cpu.expires.cpu =
+ cputime_add(timer->it.cpu.expires.cpu, incr);
+ timer->it_overrun += 1 << i;
+ delta = cputime_sub(delta, incr);
+ }
+ }
+}
+
+static inline cputime_t prof_ticks(struct task_struct *p)
+{
+ return cputime_add(p->utime, p->stime);
+}
+static inline cputime_t virt_ticks(struct task_struct *p)
+{
+ return p->utime;
+}
+
+int posix_cpu_clock_getres(const clockid_t which_clock, struct timespec *tp)
+{
+ int error = check_clock(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;
+}
+
+int posix_cpu_clock_set(const clockid_t which_clock, const struct timespec *tp)
+{
+ /*
+ * You can never reset a CPU clock, but we check for other errors
+ * in the call before failing with EPERM.
+ */
+ int error = check_clock(which_clock);
+ if (error == 0) {
+ error = -EPERM;
+ }
+ return error;
+}
+
+
+/*
+ * Sample a per-thread clock for the given task.
+ */
+static int cpu_clock_sample(const clockid_t which_clock, struct task_struct *p,
+ union cpu_time_count *cpu)
+{
+ switch (CPUCLOCK_WHICH(which_clock)) {
+ default:
+ return -EINVAL;
+ case CPUCLOCK_PROF:
+ cpu->cpu = prof_ticks(p);
+ break;
+ case CPUCLOCK_VIRT:
+ cpu->cpu = virt_ticks(p);
+ break;
+ case CPUCLOCK_SCHED:
+ cpu->sched = p->se.sum_exec_runtime + task_delta_exec(p);
+ break;
+ }
+ return 0;
+}
+
+/*
+ * Sample a process (thread group) clock for the given group_leader task.
+ * Must be called with tasklist_lock held for reading.
+ */
+static int cpu_clock_sample_group(const clockid_t which_clock,
+ struct task_struct *p,
+ union cpu_time_count *cpu)
+{
+ struct task_cputime cputime;
+
+ thread_group_cputime(p, &cputime);
+ switch (CPUCLOCK_WHICH(which_clock)) {
+ default:
+ return -EINVAL;
+ case CPUCLOCK_PROF:
+ cpu->cpu = cputime_add(cputime.utime, cputime.stime);
+ break;
+ case CPUCLOCK_VIRT:
+ cpu->cpu = cputime.utime;
+ break;
+ case CPUCLOCK_SCHED:
+ cpu->sched = cputime.sum_exec_runtime + task_delta_exec(p);
+ break;
+ }
+ return 0;
+}
+
+
+int posix_cpu_clock_get(const clockid_t which_clock, struct timespec *tp)
+{
+ const pid_t pid = CPUCLOCK_PID(which_clock);
+ int error = -EINVAL;
+ union cpu_time_count rtn;
+
+ if (pid == 0) {
+ /*
+ * Special case constant value for our own clocks.
+ * We don't have to do any lookup to find ourselves.
+ */
+ if (CPUCLOCK_PERTHREAD(which_clock)) {
+ /*
+ * Sampling just ourselves we can do with no locking.
+ */
+ error = cpu_clock_sample(which_clock,
+ current, &rtn);
+ } else {
+ read_lock(&tasklist_lock);
+ error = cpu_clock_sample_group(which_clock,
+ current, &rtn);
+ read_unlock(&tasklist_lock);
+ }
+ } else {
+ /*
+ * Find the given PID, and validate that the caller
+ * should be able to see it.
+ */
+ struct task_struct *p;
+ rcu_read_lock();
+ p = find_task_by_vpid(pid);
+ if (p) {
+ if (CPUCLOCK_PERTHREAD(which_clock)) {
+ if (same_thread_group(p, current)) {
+ error = cpu_clock_sample(which_clock,
+ p, &rtn);
+ }
+ } else {
+ read_lock(&tasklist_lock);
+ if (thread_group_leader(p) && p->signal) {
+ error =
+ cpu_clock_sample_group(which_clock,
+ p, &rtn);
+ }
+ read_unlock(&tasklist_lock);
+ }
+ }
+ rcu_read_unlock();
+ }
+
+ if (error)
+ return error;
+ sample_to_timespec(which_clock, rtn, tp);
+ return 0;
+}
+
+
+/*
+ * Validate the clockid_t for a new CPU-clock timer, and initialize the timer.
+ * This is called from sys_timer_create with the new timer already locked.
+ */
+int posix_cpu_timer_create(struct k_itimer *new_timer)
+{
+ int ret = 0;
+ const pid_t pid = CPUCLOCK_PID(new_timer->it_clock);
+ struct task_struct *p;
+
+ if (CPUCLOCK_WHICH(new_timer->it_clock) >= CPUCLOCK_MAX)
+ return -EINVAL;
+
+ INIT_LIST_HEAD(&new_timer->it.cpu.entry);
+ new_timer->it.cpu.incr.sched = 0;
+ new_timer->it.cpu.expires.sched = 0;
+
+ read_lock(&tasklist_lock);
+ if (CPUCLOCK_PERTHREAD(new_timer->it_clock)) {
+ if (pid == 0) {
+ p = current;
+ } else {
+ p = find_task_by_vpid(pid);
+ if (p && !same_thread_group(p, current))
+ p = NULL;
+ }
+ } else {
+ if (pid == 0) {
+ p = current->group_leader;
+ } else {
+ p = find_task_by_vpid(pid);
+ if (p && !thread_group_leader(p))
+ p = NULL;
+ }
+ }
+ new_timer->it.cpu.task = p;
+ if (p) {
+ get_task_struct(p);
+ } else {
+ ret = -EINVAL;
+ }
+ read_unlock(&tasklist_lock);
+
+ return ret;
+}
+
+/*
+ * 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.)
+ */
+int posix_cpu_timer_del(struct k_itimer *timer)
+{
+ struct task_struct *p = timer->it.cpu.task;
+ int ret = 0;
+
+ if (likely(p != NULL)) {
+ read_lock(&tasklist_lock);
+ if (unlikely(p->signal == NULL)) {
+ /*
+ * We raced with the reaping of the task.
+ * The deletion should have cleared us off the list.
+ */
+ BUG_ON(!list_empty(&timer->it.cpu.entry));
+ } else {
+ spin_lock(&p->sighand->siglock);
+ if (timer->it.cpu.firing)
+ ret = TIMER_RETRY;
+ else
+ list_del(&timer->it.cpu.entry);
+ spin_unlock(&p->sighand->siglock);
+ }
+ read_unlock(&tasklist_lock);
+
+ if (!ret)
+ put_task_struct(p);
+ }
+
+ return ret;
+}
+
+/*
+ * Clean out CPU timers still ticking when a thread exited. The task
+ * pointer is cleared, and the expiry time is replaced with the residual
+ * time for later timer_gettime calls to return.
+ * This must be called with the siglock held.
+ */
+static void cleanup_timers(struct list_head *head,
+ cputime_t utime, cputime_t stime,
+ unsigned long long sum_exec_runtime)
+{
+ struct cpu_timer_list *timer, *next;
+ cputime_t ptime = cputime_add(utime, stime);
+
+ list_for_each_entry_safe(timer, next, head, entry) {
+ list_del_init(&timer->entry);
+ if (cputime_lt(timer->expires.cpu, ptime)) {
+ timer->expires.cpu = cputime_zero;
+ } else {
+ timer->expires.cpu = cputime_sub(timer->expires.cpu,
+ ptime);
+ }
+ }
+
+ ++head;
+ list_for_each_entry_safe(timer, next, head, entry) {
+ list_del_init(&timer->entry);
+ if (cputime_lt(timer->expires.cpu, utime)) {
+ timer->expires.cpu = cputime_zero;
+ } else {
+ timer->expires.cpu = cputime_sub(timer->expires.cpu,
+ utime);
+ }
+ }
+
+ ++head;
+ list_for_each_entry_safe(timer, next, head, entry) {
+ list_del_init(&timer->entry);
+ if (timer->expires.sched < sum_exec_runtime) {
+ timer->expires.sched = 0;
+ } else {
+ timer->expires.sched -= sum_exec_runtime;
+ }
+ }
+}
+
+/*
+ * 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->cpu_timers,
+ tsk->utime, tsk->stime, tsk->se.sum_exec_runtime);
+
+}
+void posix_cpu_timers_exit_group(struct task_struct *tsk)
+{
+ struct task_cputime cputime;
+
+ thread_group_cputime(tsk, &cputime);
+ cleanup_timers(tsk->signal->cpu_timers,
+ cputime.utime, cputime.stime, cputime.sum_exec_runtime);
+}
+
+static void clear_dead_task(struct k_itimer *timer, union cpu_time_count now)
+{
+ /*
+ * That's all for this thread or process.
+ * We leave our residual in expires to be reported.
+ */
+ put_task_struct(timer->it.cpu.task);
+ timer->it.cpu.task = NULL;
+ timer->it.cpu.expires = cpu_time_sub(timer->it_clock,
+ timer->it.cpu.expires,
+ now);
+}
+
+/*
+ * Insert the timer on the appropriate list before any timers that
+ * expire later. This must be called with the tasklist_lock held
+ * for reading, and interrupts disabled.
+ */
+static void arm_timer(struct k_itimer *timer, union cpu_time_count now)
+{
+ struct task_struct *p = timer->it.cpu.task;
+ struct list_head *head, *listpos;
+ struct cpu_timer_list *const nt = &timer->it.cpu;
+ struct cpu_timer_list *next;
+ unsigned long i;
+
+ head = (CPUCLOCK_PERTHREAD(timer->it_clock) ?
+ p->cpu_timers : p->signal->cpu_timers);
+ head += CPUCLOCK_WHICH(timer->it_clock);
+
+ BUG_ON(!irqs_disabled());
+ spin_lock(&p->sighand->siglock);
+
+ listpos = head;
+ if (CPUCLOCK_WHICH(timer->it_clock) == CPUCLOCK_SCHED) {
+ list_for_each_entry(next, head, entry) {
+ if (next->expires.sched > nt->expires.sched)
+ break;
+ listpos = &next->entry;
+ }
+ } else {
+ list_for_each_entry(next, head, entry) {
+ if (cputime_gt(next->expires.cpu, nt->expires.cpu))
+ break;
+ listpos = &next->entry;
+ }
+ }
+ list_add(&nt->entry, listpos);
+
+ if (listpos == head) {
+ /*
+ * We are the new earliest-expiring timer.
+ * If we are a thread timer, there can always
+ * be a process timer telling us to stop earlier.
+ */
+
+ if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
+ switch (CPUCLOCK_WHICH(timer->it_clock)) {
+ default:
+ BUG();
+ case CPUCLOCK_PROF:
+ if (cputime_eq(p->cputime_expires.prof_exp,
+ cputime_zero) ||
+ cputime_gt(p->cputime_expires.prof_exp,
+ nt->expires.cpu))
+ p->cputime_expires.prof_exp =
+ nt->expires.cpu;
+ break;
+ case CPUCLOCK_VIRT:
+ if (cputime_eq(p->cputime_expires.virt_exp,
+ cputime_zero) ||
+ cputime_gt(p->cputime_expires.virt_exp,
+ nt->expires.cpu))
+ p->cputime_expires.virt_exp =
+ nt->expires.cpu;
+ break;
+ case CPUCLOCK_SCHED:
+ if (p->cputime_expires.sched_exp == 0 ||
+ p->cputime_expires.sched_exp >
+ nt->expires.sched)
+ p->cputime_expires.sched_exp =
+ nt->expires.sched;
+ break;
+ }
+ } else {
+ /*
+ * For a process timer, set the cached expiration time.
+ */
+ switch (CPUCLOCK_WHICH(timer->it_clock)) {
+ default:
+ BUG();
+ case CPUCLOCK_VIRT:
+ if (!cputime_eq(p->signal->it_virt_expires,
+ cputime_zero) &&
+ cputime_lt(p->signal->it_virt_expires,
+ timer->it.cpu.expires.cpu))
+ break;
+ p->signal->cputime_expires.virt_exp =
+ timer->it.cpu.expires.cpu;
+ break;
+ case CPUCLOCK_PROF:
+ if (!cputime_eq(p->signal->it_prof_expires,
+ cputime_zero) &&
+ cputime_lt(p->signal->it_prof_expires,
+ timer->it.cpu.expires.cpu))
+ break;
+ i = p->signal->rlim[RLIMIT_CPU].rlim_cur;
+ if (i != RLIM_INFINITY &&
+ i <= cputime_to_secs(timer->it.cpu.expires.cpu))
+ break;
+ p->signal->cputime_expires.prof_exp =
+ timer->it.cpu.expires.cpu;
+ break;
+ case CPUCLOCK_SCHED:
+ p->signal->cputime_expires.sched_exp =
+ timer->it.cpu.expires.sched;
+ break;
+ }
+ }
+ }
+
+ spin_unlock(&p->sighand->siglock);
+}
+
+/*
+ * The timer is locked, fire it and arrange for its reload.
+ */
+static void cpu_timer_fire(struct k_itimer *timer)
+{
+ 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);
+ timer->it.cpu.expires.sched = 0;
+ } else if (timer->it.cpu.incr.sched == 0) {
+ /*
+ * One-shot timer. Clear it as soon as it's fired.
+ */
+ posix_timer_event(timer, 0);
+ timer->it.cpu.expires.sched = 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_schedule(timer);
+ }
+}
+
+/*
+ * 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.)
+ */
+int posix_cpu_timer_set(struct k_itimer *timer, int flags,
+ struct itimerspec *new, struct itimerspec *old)
+{
+ struct task_struct *p = timer->it.cpu.task;
+ union cpu_time_count old_expires, new_expires, val;
+ int ret;
+
+ if (unlikely(p == NULL)) {
+ /*
+ * Timer refers to a dead task's clock.
+ */
+ return -ESRCH;
+ }
+
+ new_expires = timespec_to_sample(timer->it_clock, &new->it_value);
+
+ read_lock(&tasklist_lock);
+ /*
+ * We need the tasklist_lock to protect against reaping that
+ * clears p->signal. If p has just been reaped, we can no
+ * longer get any information about it at all.
+ */
+ if (unlikely(p->signal == NULL)) {
+ read_unlock(&tasklist_lock);
+ put_task_struct(p);
+ timer->it.cpu.task = NULL;
+ return -ESRCH;
+ }
+
+ /*
+ * Disarm any old timer after extracting its expiry time.
+ */
+ BUG_ON(!irqs_disabled());
+
+ ret = 0;
+ spin_lock(&p->sighand->siglock);
+ old_expires = timer->it.cpu.expires;
+ if (unlikely(timer->it.cpu.firing)) {
+ timer->it.cpu.firing = -1;
+ ret = TIMER_RETRY;
+ } else
+ list_del_init(&timer->it.cpu.entry);
+ spin_unlock(&p->sighand->siglock);
+
+ /*
+ * 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)) {
+ cpu_clock_sample(timer->it_clock, p, &val);
+ } else {
+ cpu_clock_sample_group(timer->it_clock, p, &val);
+ }
+
+ if (old) {
+ if (old_expires.sched == 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.
+ */
+ bump_cpu_timer(timer, val);
+ if (cpu_time_before(timer->it_clock, val,
+ timer->it.cpu.expires)) {
+ old_expires = cpu_time_sub(
+ timer->it_clock,
+ timer->it.cpu.expires, val);
+ sample_to_timespec(timer->it_clock,
+ old_expires,
+ &old->it_value);
+ } 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).
+ */
+ read_unlock(&tasklist_lock);
+ goto out;
+ }
+
+ if (new_expires.sched != 0 && !(flags & TIMER_ABSTIME)) {
+ cpu_time_add(timer->it_clock, &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).
+ */
+ timer->it.cpu.expires = new_expires;
+ if (new_expires.sched != 0 &&
+ (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
+ cpu_time_before(timer->it_clock, val, new_expires)) {
+ arm_timer(timer, val);
+ }
+
+ read_unlock(&tasklist_lock);
+
+ /*
+ * Install the new reload setting, and
+ * set up the signal and overrun bookkeeping.
+ */
+ timer->it.cpu.incr = timespec_to_sample(timer->it_clock,
+ &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.sched != 0 &&
+ (timer->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE &&
+ !cpu_time_before(timer->it_clock, 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) {
+ sample_to_timespec(timer->it_clock,
+ timer->it.cpu.incr, &old->it_interval);
+ }
+ return ret;
+}
+
+void posix_cpu_timer_get(struct k_itimer *timer, struct itimerspec *itp)
+{
+ union cpu_time_count now;
+ struct task_struct *p = timer->it.cpu.task;
+ int clear_dead;
+
+ /*
+ * Easy part: convert the reload time.
+ */
+ sample_to_timespec(timer->it_clock,
+ timer->it.cpu.incr, &itp->it_interval);
+
+ if (timer->it.cpu.expires.sched == 0) { /* Timer not armed at all. */
+ itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
+ return;
+ }
+
+ if (unlikely(p == NULL)) {
+ /*
+ * This task already died and the timer will never fire.
+ * In this case, expires is actually the dead value.
+ */
+ dead:
+ sample_to_timespec(timer->it_clock, timer->it.cpu.expires,
+ &itp->it_value);
+ return;
+ }
+
+ /*
+ * Sample the clock to take the difference with the expiry time.
+ */
+ if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
+ cpu_clock_sample(timer->it_clock, p, &now);
+ clear_dead = p->exit_state;
+ } else {
+ read_lock(&tasklist_lock);
+ if (unlikely(p->signal == NULL)) {
+ /*
+ * The process has been reaped.
+ * We can't even collect a sample any more.
+ * Call the timer disarmed, nothing else to do.
+ */
+ put_task_struct(p);
+ timer->it.cpu.task = NULL;
+ timer->it.cpu.expires.sched = 0;
+ read_unlock(&tasklist_lock);
+ goto dead;
+ } else {
+ cpu_clock_sample_group(timer->it_clock, p, &now);
+ clear_dead = (unlikely(p->exit_state) &&
+ thread_group_empty(p));
+ }
+ read_unlock(&tasklist_lock);
+ }
+
+ if ((timer->it_sigev_notify & ~SIGEV_THREAD_ID) == SIGEV_NONE) {
+ if (timer->it.cpu.incr.sched == 0 &&
+ cpu_time_before(timer->it_clock,
+ timer->it.cpu.expires, now)) {
+ /*
+ * Do-nothing timer expired and has no reload,
+ * so it's as if it was never set.
+ */
+ timer->it.cpu.expires.sched = 0;
+ itp->it_value.tv_sec = itp->it_value.tv_nsec = 0;
+ return;
+ }
+ /*
+ * Account for any expirations and reloads that should
+ * have happened.
+ */
+ bump_cpu_timer(timer, now);
+ }
+
+ if (unlikely(clear_dead)) {
+ /*
+ * We've noticed that the thread is dead, but
+ * not yet reaped. Take this opportunity to
+ * drop our task ref.
+ */
+ clear_dead_task(timer, now);
+ goto dead;
+ }
+
+ if (cpu_time_before(timer->it_clock, now, timer->it.cpu.expires)) {
+ sample_to_timespec(timer->it_clock,
+ cpu_time_sub(timer->it_clock,
+ timer->it.cpu.expires, now),
+ &itp->it_value);
+ } 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;
+ }
+}
+
+/*
+ * 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)
+{
+ int maxfire;
+ struct list_head *timers = tsk->cpu_timers;
+ struct signal_struct *const sig = tsk->signal;
+
+ maxfire = 20;
+ tsk->cputime_expires.prof_exp = cputime_zero;
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *t = list_first_entry(timers,
+ struct cpu_timer_list,
+ entry);
+ if (!--maxfire || cputime_lt(prof_ticks(tsk), t->expires.cpu)) {
+ tsk->cputime_expires.prof_exp = t->expires.cpu;
+ break;
+ }
+ t->firing = 1;
+ list_move_tail(&t->entry, firing);
+ }
+
+ ++timers;
+ maxfire = 20;
+ tsk->cputime_expires.virt_exp = cputime_zero;
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *t = list_first_entry(timers,
+ struct cpu_timer_list,
+ entry);
+ if (!--maxfire || cputime_lt(virt_ticks(tsk), t->expires.cpu)) {
+ tsk->cputime_expires.virt_exp = t->expires.cpu;
+ break;
+ }
+ t->firing = 1;
+ list_move_tail(&t->entry, firing);
+ }
+
+ ++timers;
+ maxfire = 20;
+ tsk->cputime_expires.sched_exp = 0;
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *t = list_first_entry(timers,
+ struct cpu_timer_list,
+ entry);
+ if (!--maxfire || tsk->se.sum_exec_runtime < t->expires.sched) {
+ tsk->cputime_expires.sched_exp = t->expires.sched;
+ break;
+ }
+ t->firing = 1;
+ list_move_tail(&t->entry, firing);
+ }
+
+ /*
+ * Check for the special case thread timers.
+ */
+ if (sig->rlim[RLIMIT_RTTIME].rlim_cur != RLIM_INFINITY) {
+ unsigned long hard = sig->rlim[RLIMIT_RTTIME].rlim_max;
+ unsigned long *soft = &sig->rlim[RLIMIT_RTTIME].rlim_cur;
+
+ if (hard != RLIM_INFINITY &&
+ tsk->rt.timeout > DIV_ROUND_UP(hard, USEC_PER_SEC/HZ)) {
+ /*
+ * At the hard limit, we just die.
+ * No need to calculate anything else now.
+ */
+ __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
+ return;
+ }
+ if (tsk->rt.timeout > DIV_ROUND_UP(*soft, USEC_PER_SEC/HZ)) {
+ /*
+ * At the soft limit, send a SIGXCPU every second.
+ */
+ if (sig->rlim[RLIMIT_RTTIME].rlim_cur
+ < sig->rlim[RLIMIT_RTTIME].rlim_max) {
+ sig->rlim[RLIMIT_RTTIME].rlim_cur +=
+ USEC_PER_SEC;
+ }
+ printk(KERN_INFO
+ "RT Watchdog Timeout: %s[%d]\n",
+ tsk->comm, task_pid_nr(tsk));
+ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ }
+ }
+}
+
+/*
+ * 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)
+{
+ int maxfire;
+ struct signal_struct *const sig = tsk->signal;
+ cputime_t utime, ptime, virt_expires, prof_expires;
+ unsigned long long sum_sched_runtime, sched_expires;
+ struct list_head *timers = sig->cpu_timers;
+ struct task_cputime cputime;
+
+ /*
+ * Don't sample the current process CPU clocks if there are no timers.
+ */
+ if (list_empty(&timers[CPUCLOCK_PROF]) &&
+ cputime_eq(sig->it_prof_expires, cputime_zero) &&
+ sig->rlim[RLIMIT_CPU].rlim_cur == RLIM_INFINITY &&
+ list_empty(&timers[CPUCLOCK_VIRT]) &&
+ cputime_eq(sig->it_virt_expires, cputime_zero) &&
+ list_empty(&timers[CPUCLOCK_SCHED]))
+ return;
+
+ /*
+ * Collect the current process totals.
+ */
+ thread_group_cputime(tsk, &cputime);
+ utime = cputime.utime;
+ ptime = cputime_add(utime, cputime.stime);
+ sum_sched_runtime = cputime.sum_exec_runtime;
+ maxfire = 20;
+ prof_expires = cputime_zero;
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *tl = list_first_entry(timers,
+ struct cpu_timer_list,
+ entry);
+ if (!--maxfire || cputime_lt(ptime, tl->expires.cpu)) {
+ prof_expires = tl->expires.cpu;
+ break;
+ }
+ tl->firing = 1;
+ list_move_tail(&tl->entry, firing);
+ }
+
+ ++timers;
+ maxfire = 20;
+ virt_expires = cputime_zero;
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *tl = list_first_entry(timers,
+ struct cpu_timer_list,
+ entry);
+ if (!--maxfire || cputime_lt(utime, tl->expires.cpu)) {
+ virt_expires = tl->expires.cpu;
+ break;
+ }
+ tl->firing = 1;
+ list_move_tail(&tl->entry, firing);
+ }
+
+ ++timers;
+ maxfire = 20;
+ sched_expires = 0;
+ while (!list_empty(timers)) {
+ struct cpu_timer_list *tl = list_first_entry(timers,
+ struct cpu_timer_list,
+ entry);
+ if (!--maxfire || sum_sched_runtime < tl->expires.sched) {
+ sched_expires = tl->expires.sched;
+ break;
+ }
+ tl->firing = 1;
+ list_move_tail(&tl->entry, firing);
+ }
+
+ /*
+ * Check for the special case process timers.
+ */
+ if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
+ if (cputime_ge(ptime, sig->it_prof_expires)) {
+ /* ITIMER_PROF fires and reloads. */
+ sig->it_prof_expires = sig->it_prof_incr;
+ if (!cputime_eq(sig->it_prof_expires, cputime_zero)) {
+ sig->it_prof_expires = cputime_add(
+ sig->it_prof_expires, ptime);
+ }
+ __group_send_sig_info(SIGPROF, SEND_SIG_PRIV, tsk);
+ }
+ if (!cputime_eq(sig->it_prof_expires, cputime_zero) &&
+ (cputime_eq(prof_expires, cputime_zero) ||
+ cputime_lt(sig->it_prof_expires, prof_expires))) {
+ prof_expires = sig->it_prof_expires;
+ }
+ }
+ if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
+ if (cputime_ge(utime, sig->it_virt_expires)) {
+ /* ITIMER_VIRTUAL fires and reloads. */
+ sig->it_virt_expires = sig->it_virt_incr;
+ if (!cputime_eq(sig->it_virt_expires, cputime_zero)) {
+ sig->it_virt_expires = cputime_add(
+ sig->it_virt_expires, utime);
+ }
+ __group_send_sig_info(SIGVTALRM, SEND_SIG_PRIV, tsk);
+ }
+ if (!cputime_eq(sig->it_virt_expires, cputime_zero) &&
+ (cputime_eq(virt_expires, cputime_zero) ||
+ cputime_lt(sig->it_virt_expires, virt_expires))) {
+ virt_expires = sig->it_virt_expires;
+ }
+ }
+ if (sig->rlim[RLIMIT_CPU].rlim_cur != RLIM_INFINITY) {
+ unsigned long psecs = cputime_to_secs(ptime);
+ cputime_t x;
+ if (psecs >= sig->rlim[RLIMIT_CPU].rlim_max) {
+ /*
+ * At the hard limit, we just die.
+ * No need to calculate anything else now.
+ */
+ __group_send_sig_info(SIGKILL, SEND_SIG_PRIV, tsk);
+ return;
+ }
+ if (psecs >= sig->rlim[RLIMIT_CPU].rlim_cur) {
+ /*
+ * At the soft limit, send a SIGXCPU every second.
+ */
+ __group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
+ if (sig->rlim[RLIMIT_CPU].rlim_cur
+ < sig->rlim[RLIMIT_CPU].rlim_max) {
+ sig->rlim[RLIMIT_CPU].rlim_cur++;
+ }
+ }
+ x = secs_to_cputime(sig->rlim[RLIMIT_CPU].rlim_cur);
+ if (cputime_eq(prof_expires, cputime_zero) ||
+ cputime_lt(x, prof_expires)) {
+ prof_expires = x;
+ }
+ }
+
+ if (!cputime_eq(prof_expires, cputime_zero) &&
+ (cputime_eq(sig->cputime_expires.prof_exp, cputime_zero) ||
+ cputime_gt(sig->cputime_expires.prof_exp, prof_expires)))
+ sig->cputime_expires.prof_exp = prof_expires;
+ if (!cputime_eq(virt_expires, cputime_zero) &&
+ (cputime_eq(sig->cputime_expires.virt_exp, cputime_zero) ||
+ cputime_gt(sig->cputime_expires.virt_exp, virt_expires)))
+ sig->cputime_expires.virt_exp = virt_expires;
+ if (sched_expires != 0 &&
+ (sig->cputime_expires.sched_exp == 0 ||
+ sig->cputime_expires.sched_exp > sched_expires))
+ sig->cputime_expires.sched_exp = sched_expires;
+}
+
+/*
+ * This is called from the signal code (via do_schedule_next_timer)
+ * when the last timer signal was delivered and we have to reload the timer.
+ */
+void posix_cpu_timer_schedule(struct k_itimer *timer)
+{
+ struct task_struct *p = timer->it.cpu.task;
+ union cpu_time_count now;
+
+ if (unlikely(p == NULL))
+ /*
+ * The task was cleaned up already, no future firings.
+ */
+ goto out;
+
+ /*
+ * Fetch the current sample and update the timer's expiry time.
+ */
+ if (CPUCLOCK_PERTHREAD(timer->it_clock)) {
+ cpu_clock_sample(timer->it_clock, p, &now);
+ bump_cpu_timer(timer, now);
+ if (unlikely(p->exit_state)) {
+ clear_dead_task(timer, now);
+ goto out;
+ }
+ read_lock(&tasklist_lock); /* arm_timer needs it. */
+ } else {
+ read_lock(&tasklist_lock);
+ if (unlikely(p->signal == NULL)) {
+ /*
+ * The process has been reaped.
+ * We can't even collect a sample any more.
+ */
+ put_task_struct(p);
+ timer->it.cpu.task = p = NULL;
+ timer->it.cpu.expires.sched = 0;
+ goto out_unlock;
+ } else if (unlikely(p->exit_state) && thread_group_empty(p)) {
+ /*
+ * We've noticed that the thread is dead, but
+ * not yet reaped. Take this opportunity to
+ * drop our task ref.
+ */
+ clear_dead_task(timer, now);
+ goto out_unlock;
+ }
+ cpu_clock_sample_group(timer->it_clock, p, &now);
+ bump_cpu_timer(timer, now);
+ /* Leave the tasklist_lock locked for the call below. */
+ }
+
+ /*
+ * Now re-arm for the new expiry time.
+ */
+ arm_timer(timer, now);
+
+out_unlock:
+ read_unlock(&tasklist_lock);
+
+out:
+ timer->it_overrun_last = timer->it_overrun;
+ timer->it_overrun = -1;
+ ++timer->it_requeue_pending;
+}
+
+/**
+ * task_cputime_zero - Check a task_cputime struct for all zero fields.
+ *
+ * @cputime: The struct to compare.
+ *
+ * Checks @cputime to see if all fields are zero. Returns true if all fields
+ * are zero, false if any field is nonzero.
+ */
+static inline int task_cputime_zero(const struct task_cputime *cputime)
+{
+ if (cputime_eq(cputime->utime, cputime_zero) &&
+ cputime_eq(cputime->stime, cputime_zero) &&
+ cputime->sum_exec_runtime == 0)
+ return 1;
+ return 0;
+}
+
+/**
+ * task_cputime_expired - Compare two task_cputime entities.
+ *
+ * @sample: The task_cputime structure to be checked for expiration.
+ * @expires: Expiration times, against which @sample will be checked.
+ *
+ * Checks @sample against @expires to see if any field of @sample has expired.
+ * Returns true if any field of the former is greater than the corresponding
+ * field of the latter if the latter field is set. Otherwise returns false.
+ */
+static inline int task_cputime_expired(const struct task_cputime *sample,
+ const struct task_cputime *expires)
+{
+ if (!cputime_eq(expires->utime, cputime_zero) &&
+ cputime_ge(sample->utime, expires->utime))
+ return 1;
+ if (!cputime_eq(expires->stime, cputime_zero) &&
+ cputime_ge(cputime_add(sample->utime, sample->stime),
+ expires->stime))
+ return 1;
+ if (expires->sum_exec_runtime != 0 &&
+ sample->sum_exec_runtime >= expires->sum_exec_runtime)
+ return 1;
+ return 0;
+}
+
+/**
+ * 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 int fastpath_timer_check(struct task_struct *tsk)
+{
+ struct signal_struct *sig;
+
+ /* tsk == current, ensure it is safe to use ->signal/sighand */
+ if (unlikely(tsk->exit_state))
+ return 0;
+
+ if (!task_cputime_zero(&tsk->cputime_expires)) {
+ struct task_cputime task_sample = {
+ .utime = tsk->utime,
+ .stime = tsk->stime,
+ .sum_exec_runtime = tsk->se.sum_exec_runtime
+ };
+
+ if (task_cputime_expired(&task_sample, &tsk->cputime_expires))
+ return 1;
+ }
+
+ sig = tsk->signal;
+ if (!task_cputime_zero(&sig->cputime_expires)) {
+ struct task_cputime group_sample;
+
+ thread_group_cputime(tsk, &group_sample);
+ if (task_cputime_expired(&group_sample, &sig->cputime_expires))
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * 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(struct task_struct *tsk)
+{
+ LIST_HEAD(firing);
+ struct k_itimer *timer, *next;
+
+ BUG_ON(!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;
+
+ spin_lock(&tsk->sighand->siglock);
+ /*
+ * 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.
+ */
+ spin_unlock(&tsk->sighand->siglock);
+
+ /*
+ * Now that all the timers on our list have the firing flag,
+ * noone 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.entry) {
+ int firing;
+ spin_lock(&timer->it_lock);
+ list_del_init(&timer->it.cpu.entry);
+ 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(firing >= 0)) {
+ cpu_timer_fire(timer);
+ }
+ spin_unlock(&timer->it_lock);
+ }
+}
+
+/*
+ * Set one of the process-wide special case CPU timers.
+ * The tsk->sighand->siglock must be held by the caller.
+ * The *newval argument is relative and we update it to be absolute, *oldval
+ * is absolute and we update it to be relative.
+ */
+void set_process_cpu_timer(struct task_struct *tsk, unsigned int clock_idx,
+ cputime_t *newval, cputime_t *oldval)
+{
+ union cpu_time_count now;
+ struct list_head *head;
+
+ BUG_ON(clock_idx == CPUCLOCK_SCHED);
+ cpu_clock_sample_group(clock_idx, tsk, &now);
+
+ if (oldval) {
+ if (!cputime_eq(*oldval, cputime_zero)) {
+ if (cputime_le(*oldval, now.cpu)) {
+ /* Just about to fire. */
+ *oldval = jiffies_to_cputime(1);
+ } else {
+ *oldval = cputime_sub(*oldval, now.cpu);
+ }
+ }
+
+ if (cputime_eq(*newval, cputime_zero))
+ return;
+ *newval = cputime_add(*newval, now.cpu);
+
+ /*
+ * If the RLIMIT_CPU timer will expire before the
+ * ITIMER_PROF timer, we have nothing else to do.
+ */
+ if (tsk->signal->rlim[RLIMIT_CPU].rlim_cur
+ < cputime_to_secs(*newval))
+ return;
+ }
+
+ /*
+ * Check whether there are any process timers already set to fire
+ * before this one. If so, we don't have anything more to do.
+ */
+ head = &tsk->signal->cpu_timers[clock_idx];
+ if (list_empty(head) ||
+ cputime_ge(list_first_entry(head,
+ struct cpu_timer_list, entry)->expires.cpu,
+ *newval)) {
+ switch (clock_idx) {
+ case CPUCLOCK_PROF:
+ tsk->signal->cputime_expires.prof_exp = *newval;
+ break;
+ case CPUCLOCK_VIRT:
+ tsk->signal->cputime_expires.virt_exp = *newval;
+ break;
+ }
+ }
+}
+
+static int do_cpu_nanosleep(const clockid_t which_clock, int flags,
+ struct timespec *rqtp, struct itimerspec *it)
+{
+ struct k_itimer timer;
+ 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 itimerspec zero_it;
+
+ 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 (timer.it.cpu.expires.sched == 0) {
+ /*
+ * Our timer fired and was reset.
+ */
+ 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.
+ */
+ sample_to_timespec(which_clock, timer.it.cpu.expires, rqtp);
+ posix_cpu_timer_set(&timer, 0, &zero_it, it);
+ 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;
+ }
+
+ return error;
+}
+
+int posix_cpu_nsleep(const clockid_t which_clock, int flags,
+ struct timespec *rqtp, struct timespec __user *rmtp)
+{
+ struct restart_block *restart_block =
+ &current_thread_info()->restart_block;
+ struct itimerspec it;
+ int error;
+
+ /*
+ * Diagnose required errors first.
+ */
+ if (CPUCLOCK_PERTHREAD(which_clock) &&
+ (CPUCLOCK_PID(which_clock) == 0 ||
+ CPUCLOCK_PID(which_clock) == current->pid))
+ return -EINVAL;
+
+ error = do_cpu_nanosleep(which_clock, flags, rqtp, &it);
+
+ if (error == -ERESTART_RESTARTBLOCK) {
+
+ if (flags & TIMER_ABSTIME)
+ return -ERESTARTNOHAND;
+ /*
+ * Report back to the user the time still remaining.
+ */
+ if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+ return -EFAULT;
+
+ restart_block->fn = posix_cpu_nsleep_restart;
+ restart_block->arg0 = which_clock;
+ restart_block->arg1 = (unsigned long) rmtp;
+ restart_block->arg2 = rqtp->tv_sec;
+ restart_block->arg3 = rqtp->tv_nsec;
+ }
+ return error;
+}
+
+long posix_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+ clockid_t which_clock = restart_block->arg0;
+ struct timespec __user *rmtp;
+ struct timespec t;
+ struct itimerspec it;
+ int error;
+
+ rmtp = (struct timespec __user *) restart_block->arg1;
+ t.tv_sec = restart_block->arg2;
+ t.tv_nsec = restart_block->arg3;
+
+ restart_block->fn = do_no_restart_syscall;
+ error = do_cpu_nanosleep(which_clock, TIMER_ABSTIME, &t, &it);
+
+ if (error == -ERESTART_RESTARTBLOCK) {
+ /*
+ * Report back to the user the time still remaining.
+ */
+ if (rmtp != NULL && copy_to_user(rmtp, &it.it_value, sizeof *rmtp))
+ return -EFAULT;
+
+ restart_block->fn = posix_cpu_nsleep_restart;
+ restart_block->arg0 = which_clock;
+ restart_block->arg1 = (unsigned long) rmtp;
+ restart_block->arg2 = t.tv_sec;
+ restart_block->arg3 = t.tv_nsec;
+ }
+ return error;
+
+}
+
+
+#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 timespec *tp)
+{
+ return posix_cpu_clock_getres(PROCESS_CLOCK, tp);
+}
+static int process_cpu_clock_get(const clockid_t which_clock,
+ struct timespec *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,
+ struct timespec *rqtp,
+ struct timespec __user *rmtp)
+{
+ return posix_cpu_nsleep(PROCESS_CLOCK, flags, rqtp, rmtp);
+}
+static long process_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+ return -EINVAL;
+}
+static int thread_cpu_clock_getres(const clockid_t which_clock,
+ struct timespec *tp)
+{
+ return posix_cpu_clock_getres(THREAD_CLOCK, tp);
+}
+static int thread_cpu_clock_get(const clockid_t which_clock,
+ struct timespec *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);
+}
+static int thread_cpu_nsleep(const clockid_t which_clock, int flags,
+ struct timespec *rqtp, struct timespec __user *rmtp)
+{
+ return -EINVAL;
+}
+static long thread_cpu_nsleep_restart(struct restart_block *restart_block)
+{
+ return -EINVAL;
+}
+
+static __init int init_posix_cpu_timers(void)
+{
+ struct k_clock process = {
+ .clock_getres = process_cpu_clock_getres,
+ .clock_get = process_cpu_clock_get,
+ .clock_set = do_posix_clock_nosettime,
+ .timer_create = process_cpu_timer_create,
+ .nsleep = process_cpu_nsleep,
+ .nsleep_restart = process_cpu_nsleep_restart,
+ };
+ struct k_clock thread = {
+ .clock_getres = thread_cpu_clock_getres,
+ .clock_get = thread_cpu_clock_get,
+ .clock_set = do_posix_clock_nosettime,
+ .timer_create = thread_cpu_timer_create,
+ .nsleep = thread_cpu_nsleep,
+ .nsleep_restart = thread_cpu_nsleep_restart,
+ };
+
+ register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
+ register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
+
+ return 0;
+}
+__initcall(init_posix_cpu_timers);
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