1 files changed, 301 insertions, 0 deletions

diff --git a/kernel/time/itimer.c b/kernel/time/itimer.c
new file mode 100644
index 000000000000..8d262b467573
--- /dev/null
+++ b/kernel/time/itimer.c
@@ -0,0 +1,301 @@
+/*
+ * 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);
+                        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;
+}