2 * linux/kernel/itimer.c
4 * Copyright (C) 1992 Darren Senn
7 /* These are all the functions necessary to implement itimers */
10 #include <linux/interrupt.h>
11 #include <linux/syscalls.h>
12 #include <linux/time.h>
13 #include <linux/posix-timers.h>
14 #include <linux/hrtimer.h>
16 #include <asm/uaccess.h>
19 * itimer_get_remtime - get remaining time for the timer
21 * @timer: the timer to read
23 * Returns the delta between the expiry time and now, which can be
24 * less than zero or 1usec for an pending expired timer
26 static struct timeval
itimer_get_remtime(struct hrtimer
*timer
)
28 ktime_t rem
= hrtimer_get_remaining(timer
);
31 * Racy but safe: if the itimer expires after the above
32 * hrtimer_get_remtime() call but before this condition
33 * then we return 0 - which is correct.
35 if (hrtimer_active(timer
)) {
37 rem
.tv64
= NSEC_PER_USEC
;
41 return ktime_to_timeval(rem
);
44 int do_getitimer(int which
, struct itimerval
*value
)
46 struct task_struct
*tsk
= current
;
47 cputime_t cinterval
, cval
;
51 spin_lock_irq(&tsk
->sighand
->siglock
);
52 value
->it_value
= itimer_get_remtime(&tsk
->signal
->real_timer
);
54 ktime_to_timeval(tsk
->signal
->it_real_incr
);
55 spin_unlock_irq(&tsk
->sighand
->siglock
);
58 read_lock(&tasklist_lock
);
59 spin_lock_irq(&tsk
->sighand
->siglock
);
60 cval
= tsk
->signal
->it_virt_expires
;
61 cinterval
= tsk
->signal
->it_virt_incr
;
62 if (!cputime_eq(cval
, cputime_zero
)) {
63 struct task_struct
*t
= tsk
;
64 cputime_t utime
= tsk
->signal
->utime
;
66 utime
= cputime_add(utime
, t
->utime
);
69 if (cputime_le(cval
, utime
)) { /* about to fire */
70 cval
= jiffies_to_cputime(1);
72 cval
= cputime_sub(cval
, utime
);
75 spin_unlock_irq(&tsk
->sighand
->siglock
);
76 read_unlock(&tasklist_lock
);
77 cputime_to_timeval(cval
, &value
->it_value
);
78 cputime_to_timeval(cinterval
, &value
->it_interval
);
81 read_lock(&tasklist_lock
);
82 spin_lock_irq(&tsk
->sighand
->siglock
);
83 cval
= tsk
->signal
->it_prof_expires
;
84 cinterval
= tsk
->signal
->it_prof_incr
;
85 if (!cputime_eq(cval
, cputime_zero
)) {
86 struct task_struct
*t
= tsk
;
87 cputime_t ptime
= cputime_add(tsk
->signal
->utime
,
90 ptime
= cputime_add(ptime
,
95 if (cputime_le(cval
, ptime
)) { /* about to fire */
96 cval
= jiffies_to_cputime(1);
98 cval
= cputime_sub(cval
, ptime
);
101 spin_unlock_irq(&tsk
->sighand
->siglock
);
102 read_unlock(&tasklist_lock
);
103 cputime_to_timeval(cval
, &value
->it_value
);
104 cputime_to_timeval(cinterval
, &value
->it_interval
);
112 asmlinkage
long sys_getitimer(int which
, struct itimerval __user
*value
)
115 struct itimerval get_buffer
;
118 error
= do_getitimer(which
, &get_buffer
);
120 copy_to_user(value
, &get_buffer
, sizeof(get_buffer
)))
128 * The timer is automagically restarted, when interval != 0
130 enum hrtimer_restart
it_real_fn(struct hrtimer
*timer
)
132 struct signal_struct
*sig
=
133 container_of(timer
, struct signal_struct
, real_timer
);
135 send_group_sig_info(SIGALRM
, SEND_SIG_PRIV
, sig
->tsk
);
137 return HRTIMER_NORESTART
;
141 * We do not care about correctness. We just sanitize the values so
142 * the ktime_t operations which expect normalized values do not
143 * break. This converts negative values to long timeouts similar to
144 * the code in kernel versions < 2.6.16
146 * Print a limited number of warning messages when an invalid timeval
149 static void fixup_timeval(struct timeval
*tv
, int interval
)
151 static int warnlimit
= 10;
157 "setitimer: %s (pid = %d) provided "
158 "invalid timeval %s: tv_sec = %ld tv_usec = %ld\n",
159 current
->comm
, current
->pid
,
160 interval
? "it_interval" : "it_value",
161 tv
->tv_sec
, (long) tv
->tv_usec
);
165 if (tmp
>= USEC_PER_SEC
) {
166 tv
->tv_usec
= tmp
% USEC_PER_SEC
;
167 tv
->tv_sec
+= tmp
/ USEC_PER_SEC
;
172 tv
->tv_sec
= LONG_MAX
;
176 * Returns true if the timeval is in canonical form
178 #define timeval_valid(t) \
179 (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
182 * Check for invalid timevals, sanitize them and print a limited
183 * number of warnings.
185 static void check_itimerval(struct itimerval
*value
) {
187 if (unlikely(!timeval_valid(&value
->it_value
)))
188 fixup_timeval(&value
->it_value
, 0);
190 if (unlikely(!timeval_valid(&value
->it_interval
)))
191 fixup_timeval(&value
->it_interval
, 1);
194 int do_setitimer(int which
, struct itimerval
*value
, struct itimerval
*ovalue
)
196 struct task_struct
*tsk
= current
;
197 struct hrtimer
*timer
;
199 cputime_t cval
, cinterval
, nval
, ninterval
;
202 * Validate the timevals in value.
204 * Note: Although the spec requires that invalid values shall
205 * return -EINVAL, we just fixup the value and print a limited
206 * number of warnings in order not to break users of this
207 * historical misfeature.
209 * Scheduled for replacement in March 2007
211 check_itimerval(value
);
216 spin_lock_irq(&tsk
->sighand
->siglock
);
217 timer
= &tsk
->signal
->real_timer
;
219 ovalue
->it_value
= itimer_get_remtime(timer
);
221 = ktime_to_timeval(tsk
->signal
->it_real_incr
);
223 /* We are sharing ->siglock with it_real_fn() */
224 if (hrtimer_try_to_cancel(timer
) < 0) {
225 spin_unlock_irq(&tsk
->sighand
->siglock
);
228 expires
= timeval_to_ktime(value
->it_value
);
229 if (expires
.tv64
!= 0) {
230 tsk
->signal
->it_real_incr
=
231 timeval_to_ktime(value
->it_interval
);
232 hrtimer_start(timer
, expires
, HRTIMER_MODE_REL
);
234 tsk
->signal
->it_real_incr
.tv64
= 0;
236 spin_unlock_irq(&tsk
->sighand
->siglock
);
239 nval
= timeval_to_cputime(&value
->it_value
);
240 ninterval
= timeval_to_cputime(&value
->it_interval
);
241 read_lock(&tasklist_lock
);
242 spin_lock_irq(&tsk
->sighand
->siglock
);
243 cval
= tsk
->signal
->it_virt_expires
;
244 cinterval
= tsk
->signal
->it_virt_incr
;
245 if (!cputime_eq(cval
, cputime_zero
) ||
246 !cputime_eq(nval
, cputime_zero
)) {
247 if (cputime_gt(nval
, cputime_zero
))
248 nval
= cputime_add(nval
,
249 jiffies_to_cputime(1));
250 set_process_cpu_timer(tsk
, CPUCLOCK_VIRT
,
253 tsk
->signal
->it_virt_expires
= nval
;
254 tsk
->signal
->it_virt_incr
= ninterval
;
255 spin_unlock_irq(&tsk
->sighand
->siglock
);
256 read_unlock(&tasklist_lock
);
258 cputime_to_timeval(cval
, &ovalue
->it_value
);
259 cputime_to_timeval(cinterval
, &ovalue
->it_interval
);
263 nval
= timeval_to_cputime(&value
->it_value
);
264 ninterval
= timeval_to_cputime(&value
->it_interval
);
265 read_lock(&tasklist_lock
);
266 spin_lock_irq(&tsk
->sighand
->siglock
);
267 cval
= tsk
->signal
->it_prof_expires
;
268 cinterval
= tsk
->signal
->it_prof_incr
;
269 if (!cputime_eq(cval
, cputime_zero
) ||
270 !cputime_eq(nval
, cputime_zero
)) {
271 if (cputime_gt(nval
, cputime_zero
))
272 nval
= cputime_add(nval
,
273 jiffies_to_cputime(1));
274 set_process_cpu_timer(tsk
, CPUCLOCK_PROF
,
277 tsk
->signal
->it_prof_expires
= nval
;
278 tsk
->signal
->it_prof_incr
= ninterval
;
279 spin_unlock_irq(&tsk
->sighand
->siglock
);
280 read_unlock(&tasklist_lock
);
282 cputime_to_timeval(cval
, &ovalue
->it_value
);
283 cputime_to_timeval(cinterval
, &ovalue
->it_interval
);
293 * alarm_setitimer - set alarm in seconds
295 * @seconds: number of seconds until alarm
296 * 0 disables the alarm
298 * Returns the remaining time in seconds of a pending timer or 0 when
299 * the timer is not active.
301 * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
302 * negative timeval settings which would cause immediate expiry.
304 unsigned int alarm_setitimer(unsigned int seconds
)
306 struct itimerval it_new
, it_old
;
308 #if BITS_PER_LONG < 64
309 if (seconds
> INT_MAX
)
312 it_new
.it_value
.tv_sec
= seconds
;
313 it_new
.it_value
.tv_usec
= 0;
314 it_new
.it_interval
.tv_sec
= it_new
.it_interval
.tv_usec
= 0;
316 do_setitimer(ITIMER_REAL
, &it_new
, &it_old
);
319 * We can't return 0 if we have an alarm pending ... And we'd
320 * better return too much than too little anyway
322 if ((!it_old
.it_value
.tv_sec
&& it_old
.it_value
.tv_usec
) ||
323 it_old
.it_value
.tv_usec
>= 500000)
324 it_old
.it_value
.tv_sec
++;
326 return it_old
.it_value
.tv_sec
;
329 asmlinkage
long sys_setitimer(int which
,
330 struct itimerval __user
*value
,
331 struct itimerval __user
*ovalue
)
333 struct itimerval set_buffer
, get_buffer
;
337 if(copy_from_user(&set_buffer
, value
, sizeof(set_buffer
)))
340 memset((char *) &set_buffer
, 0, sizeof(set_buffer
));
342 error
= do_setitimer(which
, &set_buffer
, ovalue
? &get_buffer
: NULL
);
343 if (error
|| !ovalue
)
346 if (copy_to_user(ovalue
, &get_buffer
, sizeof(get_buffer
)))