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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - kernel/itimer.c
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 spin_lock_irq(&tsk
->sighand
->siglock
);
59 cval
= tsk
->signal
->it_virt_expires
;
60 cinterval
= tsk
->signal
->it_virt_incr
;
61 if (!cputime_eq(cval
, cputime_zero
)) {
62 struct task_cputime cputime
;
65 thread_group_cputimer(tsk
, &cputime
);
66 utime
= cputime
.utime
;
67 if (cputime_le(cval
, utime
)) { /* about to fire */
68 cval
= jiffies_to_cputime(1);
70 cval
= cputime_sub(cval
, utime
);
73 spin_unlock_irq(&tsk
->sighand
->siglock
);
74 cputime_to_timeval(cval
, &value
->it_value
);
75 cputime_to_timeval(cinterval
, &value
->it_interval
);
78 spin_lock_irq(&tsk
->sighand
->siglock
);
79 cval
= tsk
->signal
->it_prof_expires
;
80 cinterval
= tsk
->signal
->it_prof_incr
;
81 if (!cputime_eq(cval
, cputime_zero
)) {
82 struct task_cputime times
;
85 thread_group_cputimer(tsk
, ×
);
86 ptime
= cputime_add(times
.utime
, times
.stime
);
87 if (cputime_le(cval
, ptime
)) { /* about to fire */
88 cval
= jiffies_to_cputime(1);
90 cval
= cputime_sub(cval
, ptime
);
93 spin_unlock_irq(&tsk
->sighand
->siglock
);
94 cputime_to_timeval(cval
, &value
->it_value
);
95 cputime_to_timeval(cinterval
, &value
->it_interval
);
103 SYSCALL_DEFINE2(getitimer
, int, which
, struct itimerval __user
*, value
)
106 struct itimerval get_buffer
;
109 error
= do_getitimer(which
, &get_buffer
);
111 copy_to_user(value
, &get_buffer
, sizeof(get_buffer
)))
119 * The timer is automagically restarted, when interval != 0
121 enum hrtimer_restart
it_real_fn(struct hrtimer
*timer
)
123 struct signal_struct
*sig
=
124 container_of(timer
, struct signal_struct
, real_timer
);
126 kill_pid_info(SIGALRM
, SEND_SIG_PRIV
, sig
->leader_pid
);
128 return HRTIMER_NORESTART
;
132 * Returns true if the timeval is in canonical form
134 #define timeval_valid(t) \
135 (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
137 int do_setitimer(int which
, struct itimerval
*value
, struct itimerval
*ovalue
)
139 struct task_struct
*tsk
= current
;
140 struct hrtimer
*timer
;
142 cputime_t cval
, cinterval
, nval
, ninterval
;
145 * Validate the timevals in value.
147 if (!timeval_valid(&value
->it_value
) ||
148 !timeval_valid(&value
->it_interval
))
154 spin_lock_irq(&tsk
->sighand
->siglock
);
155 timer
= &tsk
->signal
->real_timer
;
157 ovalue
->it_value
= itimer_get_remtime(timer
);
159 = ktime_to_timeval(tsk
->signal
->it_real_incr
);
161 /* We are sharing ->siglock with it_real_fn() */
162 if (hrtimer_try_to_cancel(timer
) < 0) {
163 spin_unlock_irq(&tsk
->sighand
->siglock
);
166 expires
= timeval_to_ktime(value
->it_value
);
167 if (expires
.tv64
!= 0) {
168 tsk
->signal
->it_real_incr
=
169 timeval_to_ktime(value
->it_interval
);
170 hrtimer_start(timer
, expires
, HRTIMER_MODE_REL
);
172 tsk
->signal
->it_real_incr
.tv64
= 0;
174 spin_unlock_irq(&tsk
->sighand
->siglock
);
177 nval
= timeval_to_cputime(&value
->it_value
);
178 ninterval
= timeval_to_cputime(&value
->it_interval
);
179 spin_lock_irq(&tsk
->sighand
->siglock
);
180 cval
= tsk
->signal
->it_virt_expires
;
181 cinterval
= tsk
->signal
->it_virt_incr
;
182 if (!cputime_eq(cval
, cputime_zero
) ||
183 !cputime_eq(nval
, cputime_zero
)) {
184 if (cputime_gt(nval
, cputime_zero
))
185 nval
= cputime_add(nval
,
186 jiffies_to_cputime(1));
187 set_process_cpu_timer(tsk
, CPUCLOCK_VIRT
,
190 tsk
->signal
->it_virt_expires
= nval
;
191 tsk
->signal
->it_virt_incr
= ninterval
;
192 spin_unlock_irq(&tsk
->sighand
->siglock
);
194 cputime_to_timeval(cval
, &ovalue
->it_value
);
195 cputime_to_timeval(cinterval
, &ovalue
->it_interval
);
199 nval
= timeval_to_cputime(&value
->it_value
);
200 ninterval
= timeval_to_cputime(&value
->it_interval
);
201 spin_lock_irq(&tsk
->sighand
->siglock
);
202 cval
= tsk
->signal
->it_prof_expires
;
203 cinterval
= tsk
->signal
->it_prof_incr
;
204 if (!cputime_eq(cval
, cputime_zero
) ||
205 !cputime_eq(nval
, cputime_zero
)) {
206 if (cputime_gt(nval
, cputime_zero
))
207 nval
= cputime_add(nval
,
208 jiffies_to_cputime(1));
209 set_process_cpu_timer(tsk
, CPUCLOCK_PROF
,
212 tsk
->signal
->it_prof_expires
= nval
;
213 tsk
->signal
->it_prof_incr
= ninterval
;
214 spin_unlock_irq(&tsk
->sighand
->siglock
);
216 cputime_to_timeval(cval
, &ovalue
->it_value
);
217 cputime_to_timeval(cinterval
, &ovalue
->it_interval
);
227 * alarm_setitimer - set alarm in seconds
229 * @seconds: number of seconds until alarm
230 * 0 disables the alarm
232 * Returns the remaining time in seconds of a pending timer or 0 when
233 * the timer is not active.
235 * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
236 * negative timeval settings which would cause immediate expiry.
238 unsigned int alarm_setitimer(unsigned int seconds
)
240 struct itimerval it_new
, it_old
;
242 #if BITS_PER_LONG < 64
243 if (seconds
> INT_MAX
)
246 it_new
.it_value
.tv_sec
= seconds
;
247 it_new
.it_value
.tv_usec
= 0;
248 it_new
.it_interval
.tv_sec
= it_new
.it_interval
.tv_usec
= 0;
250 do_setitimer(ITIMER_REAL
, &it_new
, &it_old
);
253 * We can't return 0 if we have an alarm pending ... And we'd
254 * better return too much than too little anyway
256 if ((!it_old
.it_value
.tv_sec
&& it_old
.it_value
.tv_usec
) ||
257 it_old
.it_value
.tv_usec
>= 500000)
258 it_old
.it_value
.tv_sec
++;
260 return it_old
.it_value
.tv_sec
;
263 SYSCALL_DEFINE3(setitimer
, int, which
, struct itimerval __user
*, value
,
264 struct itimerval __user
*, ovalue
)
266 struct itimerval set_buffer
, get_buffer
;
270 if(copy_from_user(&set_buffer
, value
, sizeof(set_buffer
)))
273 memset((char *) &set_buffer
, 0, sizeof(set_buffer
));
275 error
= do_setitimer(which
, &set_buffer
, ovalue
? &get_buffer
: NULL
);
276 if (error
|| !ovalue
)
279 if (copy_to_user(ovalue
, &get_buffer
, sizeof(get_buffer
)))