--- /dev/null
+/*
+ * linux/kernel/itimer.c
+ *
+ * Copyright (C) 1992 Darren Senn
+ */
+
+/* These are all the functions necessary to implement itimers */
+
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/syscalls.h>
+#include <linux/time.h>
+#include <linux/posix-timers.h>
+#include <linux/hrtimer.h>
+#include <trace/events/timer.h>
+
+#include <asm/uaccess.h>
+
+/**
+ * itimer_get_remtime - get remaining time for the timer
+ *
+ * @timer: the timer to read
+ *
+ * Returns the delta between the expiry time and now, which can be
+ * less than zero or 1usec for an pending expired timer
+ */
+static struct timeval itimer_get_remtime(struct hrtimer *timer)
+{
+ ktime_t rem = hrtimer_get_remaining(timer);
+
+ /*
+ * Racy but safe: if the itimer expires after the above
+ * hrtimer_get_remtime() call but before this condition
+ * then we return 0 - which is correct.
+ */
+ if (hrtimer_active(timer)) {
+ if (rem.tv64 <= 0)
+ rem.tv64 = NSEC_PER_USEC;
+ } else
+ rem.tv64 = 0;
+
+ return ktime_to_timeval(rem);
+}
+
+static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+ struct itimerval *const value)
+{
+ cputime_t cval, cinterval;
+ struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+ spin_lock_irq(&tsk->sighand->siglock);
+
+ cval = it->expires;
+ cinterval = it->incr;
+ if (cval) {
+ struct task_cputime cputime;
+ cputime_t t;
+
+ thread_group_cputimer(tsk, &cputime);
+ if (clock_id == CPUCLOCK_PROF)
+ t = cputime.utime + cputime.stime;
+ else
+ /* CPUCLOCK_VIRT */
+ t = cputime.utime;
+
+ if (cval < t)
+ /* about to fire */
+ cval = cputime_one_jiffy;
+ else
+ cval = cval - t;
+ }
+
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ cputime_to_timeval(cval, &value->it_value);
+ cputime_to_timeval(cinterval, &value->it_interval);
+}
+
+int do_getitimer(int which, struct itimerval *value)
+{
+ struct task_struct *tsk = current;
+
+ switch (which) {
+ case ITIMER_REAL:
+ spin_lock_irq(&tsk->sighand->siglock);
+ value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
+ value->it_interval =
+ ktime_to_timeval(tsk->signal->it_real_incr);
+ spin_unlock_irq(&tsk->sighand->siglock);
+ break;
+ case ITIMER_VIRTUAL:
+ get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
+ break;
+ case ITIMER_PROF:
+ get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
+ break;
+ default:
+ return(-EINVAL);
+ }
+ return 0;
+}
+
+SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
+{
+ int error = -EFAULT;
+ struct itimerval get_buffer;
+
+ if (value) {
+ error = do_getitimer(which, &get_buffer);
+ if (!error &&
+ copy_to_user(value, &get_buffer, sizeof(get_buffer)))
+ error = -EFAULT;
+ }
+ return error;
+}
+
+
+/*
+ * The timer is automagically restarted, when interval != 0
+ */
+enum hrtimer_restart it_real_fn(struct hrtimer *timer)
+{
+ struct signal_struct *sig =
+ container_of(timer, struct signal_struct, real_timer);
+
+ trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
+ kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
+
+ return HRTIMER_NORESTART;
+}
+
+static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns)
+{
+ struct timespec ts;
+ s64 cpu_ns;
+
+ cputime_to_timespec(ct, &ts);
+ cpu_ns = timespec_to_ns(&ts);
+
+ return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns;
+}
+
+static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
+ const struct itimerval *const value,
+ struct itimerval *const ovalue)
+{
+ cputime_t cval, nval, cinterval, ninterval;
+ s64 ns_ninterval, ns_nval;
+ u32 error, incr_error;
+ struct cpu_itimer *it = &tsk->signal->it[clock_id];
+
+ nval = timeval_to_cputime(&value->it_value);
+ ns_nval = timeval_to_ns(&value->it_value);
+ ninterval = timeval_to_cputime(&value->it_interval);
+ ns_ninterval = timeval_to_ns(&value->it_interval);
+
+ error = cputime_sub_ns(nval, ns_nval);
+ incr_error = cputime_sub_ns(ninterval, ns_ninterval);
+
+ spin_lock_irq(&tsk->sighand->siglock);
+
+ cval = it->expires;
+ cinterval = it->incr;
+ if (cval || nval) {
+ if (nval > 0)
+ nval += cputime_one_jiffy;
+ set_process_cpu_timer(tsk, clock_id, &nval, &cval);
+ }
+ it->expires = nval;
+ it->incr = ninterval;
+ it->error = error;
+ it->incr_error = incr_error;
+ trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
+ ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
+
+ spin_unlock_irq(&tsk->sighand->siglock);
+
+ if (ovalue) {
+ cputime_to_timeval(cval, &ovalue->it_value);
+ cputime_to_timeval(cinterval, &ovalue->it_interval);
+ }
+}
+
+/*
+ * Returns true if the timeval is in canonical form
+ */
+#define timeval_valid(t) \
+ (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
+
+int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
+{
+ struct task_struct *tsk = current;
+ struct hrtimer *timer;
+ ktime_t expires;
+
+ /*
+ * Validate the timevals in value.
+ */
+ if (!timeval_valid(&value->it_value) ||
+ !timeval_valid(&value->it_interval))
+ return -EINVAL;
+
+ switch (which) {
+ case ITIMER_REAL:
+again:
+ spin_lock_irq(&tsk->sighand->siglock);
+ timer = &tsk->signal->real_timer;
+ if (ovalue) {
+ ovalue->it_value = itimer_get_remtime(timer);
+ ovalue->it_interval
+ = ktime_to_timeval(tsk->signal->it_real_incr);
+ }
+ /* We are sharing ->siglock with it_real_fn() */
+ if (hrtimer_try_to_cancel(timer) < 0) {
+ spin_unlock_irq(&tsk->sighand->siglock);
+ hrtimer_wait_for_timer(&tsk->signal->real_timer);
+ goto again;
+ }
+ expires = timeval_to_ktime(value->it_value);
+ if (expires.tv64 != 0) {
+ tsk->signal->it_real_incr =
+ timeval_to_ktime(value->it_interval);
+ hrtimer_start(timer, expires, HRTIMER_MODE_REL);
+ } else
+ tsk->signal->it_real_incr.tv64 = 0;
+
+ trace_itimer_state(ITIMER_REAL, value, 0);
+ spin_unlock_irq(&tsk->sighand->siglock);
+ break;
+ case ITIMER_VIRTUAL:
+ set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
+ break;
+ case ITIMER_PROF:
+ set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
+}
+
+/**
+ * alarm_setitimer - set alarm in seconds
+ *
+ * @seconds: number of seconds until alarm
+ * 0 disables the alarm
+ *
+ * Returns the remaining time in seconds of a pending timer or 0 when
+ * the timer is not active.
+ *
+ * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
+ * negative timeval settings which would cause immediate expiry.
+ */
+unsigned int alarm_setitimer(unsigned int seconds)
+{
+ struct itimerval it_new, it_old;
+
+#if BITS_PER_LONG < 64
+ if (seconds > INT_MAX)
+ seconds = INT_MAX;
+#endif
+ it_new.it_value.tv_sec = seconds;
+ it_new.it_value.tv_usec = 0;
+ it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
+
+ do_setitimer(ITIMER_REAL, &it_new, &it_old);
+
+ /*
+ * We can't return 0 if we have an alarm pending ... And we'd
+ * better return too much than too little anyway
+ */
+ if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
+ it_old.it_value.tv_usec >= 500000)
+ it_old.it_value.tv_sec++;
+
+ return it_old.it_value.tv_sec;
+}
+
+SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
+ struct itimerval __user *, ovalue)
+{
+ struct itimerval set_buffer, get_buffer;
+ int error;
+
+ if (value) {
+ if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
+ return -EFAULT;
+ } else {
+ memset(&set_buffer, 0, sizeof(set_buffer));
+ printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
+ " Misfeature support will be removed\n",
+ current->comm);
+ }
+
+ error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
+ if (error || !ovalue)
+ return error;
+
+ if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
+ return -EFAULT;
+ return 0;
+}
Code Review / kvmfornfv.git / blobdiff