| 1 | |
| 2 | * linux/kernel/itimer.c
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| 3 | *
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| 4 | * Copyright (C) 1992 Darren Senn
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| 5 |
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| 6 |
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| 7 |
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| 8 |
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| 9 | #include <linux/mm.h>
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| 10 | #include <linux/smp_lock.h>
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| 11 | #include <linux/interrupt.h>
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| 12 | #include <linux/syscalls.h>
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| 13 | #include <linux/time.h>
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| 14 | #include <linux/posix-timers.h>
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| 15 |
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| 16 | #include <asm/uaccess.h>
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| 17 |
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| 18 | static unsigned long it_real_value(struct signal_struct *sig)
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| 19 | {
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| 20 | unsigned long val = 0;
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| 21 | if (timer_pending(&sig->real_timer)) {
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| 22 | val = sig->real_timer.expires - jiffies;
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| 23 |
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| 24 |
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| 25 | if ((long) val <= 0)
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| 26 | val = 1;
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| 27 | }
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| 28 | return val;
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| 29 | }
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| 30 |
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| 31 | int do_getitimer(int which, struct itimerval *value)
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| 32 | {
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| 33 | struct task_struct *tsk = current;
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| 34 | unsigned long interval, val;
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| 35 | cputime_t cinterval, cval;
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| 36 |
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| 37 | switch (which) {
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| 38 | case ITIMER_REAL:
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| 39 | spin_lock_irq(&tsk->sighand->siglock);
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| 40 | interval = tsk->signal->it_real_incr;
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| 41 | val = it_real_value(tsk->signal);
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| 42 | spin_unlock_irq(&tsk->sighand->siglock);
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| 43 | jiffies_to_timeval(val, &value->it_value);
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| 44 | jiffies_to_timeval(interval, &value->it_interval);
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| 45 | break;
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| 46 | case ITIMER_VIRTUAL:
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| 47 | read_lock(&tasklist_lock);
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| 48 | spin_lock_irq(&tsk->sighand->siglock);
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| 49 | cval = tsk->signal->it_virt_expires;
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| 50 | cinterval = tsk->signal->it_virt_incr;
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| 51 | if (!cputime_eq(cval, cputime_zero)) {
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| 52 | struct task_struct *t = tsk;
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| 53 | cputime_t utime = tsk->signal->utime;
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| 54 | do {
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| 55 | utime = cputime_add(utime, t->utime);
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| 56 | t = next_thread(t);
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| 57 | } while (t != tsk);
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| 58 | if (cputime_le(cval, utime)) {
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| 59 | cval = jiffies_to_cputime(1);
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| 60 | } else {
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| 61 | cval = cputime_sub(cval, utime);
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| 62 | }
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| 63 | }
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| 64 | spin_unlock_irq(&tsk->sighand->siglock);
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| 65 | read_unlock(&tasklist_lock);
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| 66 | cputime_to_timeval(cval, &value->it_value);
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| 67 | cputime_to_timeval(cinterval, &value->it_interval);
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| 68 | break;
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| 69 | case ITIMER_PROF:
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| 70 | read_lock(&tasklist_lock);
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| 71 | spin_lock_irq(&tsk->sighand->siglock);
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| 72 | cval = tsk->signal->it_prof_expires;
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| 73 | cinterval = tsk->signal->it_prof_incr;
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| 74 | if (!cputime_eq(cval, cputime_zero)) {
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| 75 | struct task_struct *t = tsk;
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| 76 | cputime_t ptime = cputime_add(tsk->signal->utime,
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| 77 | tsk->signal->stime);
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| 78 | do {
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| 79 | ptime = cputime_add(ptime,
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| 80 | cputime_add(t->utime,
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| 81 | t->stime));
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| 82 | t = next_thread(t);
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| 83 | } while (t != tsk);
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| 84 | if (cputime_le(cval, ptime)) {
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| 85 | cval = jiffies_to_cputime(1);
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| 86 | } else {
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| 87 | cval = cputime_sub(cval, ptime);
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| 88 | }
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| 89 | }
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| 90 | spin_unlock_irq(&tsk->sighand->siglock);
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| 91 | read_unlock(&tasklist_lock);
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| 92 | cputime_to_timeval(cval, &value->it_value);
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| 93 | cputime_to_timeval(cinterval, &value->it_interval);
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| 94 | break;
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| 95 | default:
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| 96 | return(-EINVAL);
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| 97 | }
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| 98 | return 0;
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| 99 | }
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| 100 |
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| 101 | asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
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| 102 | {
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| 103 | int error = -EFAULT;
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| 104 | struct itimerval get_buffer;
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| 105 |
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| 106 | if (value) {
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| 107 | error = do_getitimer(which, &get_buffer);
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| 108 | if (!error &&
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| 109 | copy_to_user(value, &get_buffer, sizeof(get_buffer)))
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| 110 | error = -EFAULT;
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| 111 | }
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| 112 | return error;
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| 113 | }
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| 114 |
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| 115 |
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| 116 | void it_real_fn(unsigned long __data)
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| 117 | {
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| 118 | struct task_struct * p = (struct task_struct *) __data;
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| 119 | unsigned long inc = p->signal->it_real_incr;
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| 120 |
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| 121 | send_group_sig_info(SIGALRM, SEND_SIG_PRIV, p);
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| 122 |
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| 123 | |
| 124 | * Now restart the timer if necessary. We don't need any locking
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| 125 | * here because do_setitimer makes sure we have finished running
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| 126 | * before it touches anything.
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| 127 | * Note, we KNOW we are (or should be) at a jiffie edge here so
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| 128 | * we don't need the +1 stuff. Also, we want to use the prior
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| 129 | * expire value so as to not "slip" a jiffie if we are late.
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| 130 | * Deal with requesting a time prior to "now" here rather than
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| 131 | * in add_timer.
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| 132 |
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| 133 | if (!inc)
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| 134 | return;
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| 135 | while (time_before_eq(p->signal->real_timer.expires, jiffies))
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| 136 | p->signal->real_timer.expires += inc;
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| 137 | add_timer(&p->signal->real_timer);
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| 138 | }
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| 139 |
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| 140 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
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| 141 | {
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| 142 | struct task_struct *tsk = current;
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| 143 | unsigned long val, interval, expires;
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| 144 | cputime_t cval, cinterval, nval, ninterval;
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| 145 |
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| 146 | switch (which) {
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| 147 | case ITIMER_REAL:
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| 148 | again:
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| 149 | spin_lock_irq(&tsk->sighand->siglock);
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| 150 | interval = tsk->signal->it_real_incr;
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| 151 | val = it_real_value(tsk->signal);
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| 152 |
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| 153 | if (try_to_del_timer_sync(&tsk->signal->real_timer) < 0) {
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| 154 | spin_unlock_irq(&tsk->sighand->siglock);
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| 155 | goto again;
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| 156 | }
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| 157 | tsk->signal->it_real_incr =
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| 158 | timeval_to_jiffies(&value->it_interval);
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| 159 | expires = timeval_to_jiffies(&value->it_value);
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| 160 | if (expires)
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| 161 | mod_timer(&tsk->signal->real_timer,
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| 162 | jiffies + 1 + expires);
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| 163 | spin_unlock_irq(&tsk->sighand->siglock);
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| 164 | if (ovalue) {
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| 165 | jiffies_to_timeval(val, &ovalue->it_value);
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| 166 | jiffies_to_timeval(interval,
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| 167 | &ovalue->it_interval);
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| 168 | }
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| 169 | break;
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| 170 | case ITIMER_VIRTUAL:
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| 171 | nval = timeval_to_cputime(&value->it_value);
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| 172 | ninterval = timeval_to_cputime(&value->it_interval);
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| 173 | read_lock(&tasklist_lock);
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| 174 | spin_lock_irq(&tsk->sighand->siglock);
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| 175 | cval = tsk->signal->it_virt_expires;
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| 176 | cinterval = tsk->signal->it_virt_incr;
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| 177 | if (!cputime_eq(cval, cputime_zero) ||
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| 178 | !cputime_eq(nval, cputime_zero)) {
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| 179 | if (cputime_gt(nval, cputime_zero))
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| 180 | nval = cputime_add(nval,
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| 181 | jiffies_to_cputime(1));
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| 182 | set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
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| 183 | &nval, &cval);
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| 184 | }
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| 185 | tsk->signal->it_virt_expires = nval;
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| 186 | tsk->signal->it_virt_incr = ninterval;
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| 187 | spin_unlock_irq(&tsk->sighand->siglock);
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| 188 | read_unlock(&tasklist_lock);
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| 189 | if (ovalue) {
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| 190 | cputime_to_timeval(cval, &ovalue->it_value);
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| 191 | cputime_to_timeval(cinterval, &ovalue->it_interval);
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| 192 | }
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| 193 | break;
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| 194 | case ITIMER_PROF:
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| 195 | nval = timeval_to_cputime(&value->it_value);
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| 196 | ninterval = timeval_to_cputime(&value->it_interval);
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| 197 | read_lock(&tasklist_lock);
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| 198 | spin_lock_irq(&tsk->sighand->siglock);
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| 199 | cval = tsk->signal->it_prof_expires;
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| 200 | cinterval = tsk->signal->it_prof_incr;
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| 201 | if (!cputime_eq(cval, cputime_zero) ||
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| 202 | !cputime_eq(nval, cputime_zero)) {
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| 203 | if (cputime_gt(nval, cputime_zero))
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| 204 | nval = cputime_add(nval,
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| 205 | jiffies_to_cputime(1));
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| 206 | set_process_cpu_timer(tsk, CPUCLOCK_PROF,
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| 207 | &nval, &cval);
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| 208 | }
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| 209 | tsk->signal->it_prof_expires = nval;
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| 210 | tsk->signal->it_prof_incr = ninterval;
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| 211 | spin_unlock_irq(&tsk->sighand->siglock);
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| 212 | read_unlock(&tasklist_lock);
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| 213 | if (ovalue) {
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| 214 | cputime_to_timeval(cval, &ovalue->it_value);
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| 215 | cputime_to_timeval(cinterval, &ovalue->it_interval);
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| 216 | }
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| 217 | break;
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| 218 | default:
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| 219 | return -EINVAL;
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| 220 | }
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| 221 | return 0;
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| 222 | }
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| 223 |
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| 224 | asmlinkage long sys_setitimer(int which,
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| 225 | struct itimerval __user *value,
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| 226 | struct itimerval __user *ovalue)
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| 227 | {
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| 228 | struct itimerval set_buffer, get_buffer;
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| 229 | int error;
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| 230 |
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| 231 | if (value) {
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| 232 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
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| 233 | return -EFAULT;
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| 234 | } else
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| 235 | memset((char *) &set_buffer, 0, sizeof(set_buffer));
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| 236 |
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| 237 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
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| 238 | if (error || !ovalue)
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| 239 | return error;
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| 240 |
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| 241 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
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| 242 | return -EFAULT;
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| 243 | return 0;
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| 244 | }
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