Merge tag 'seccomp-v4.16-rc3' of https://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6-block.git] / kernel / time / itimer.c
CommitLineData
b2441318 1// SPDX-License-Identifier: GPL-2.0
1da177e4
LT
2/*
3 * linux/kernel/itimer.c
4 *
5 * Copyright (C) 1992 Darren Senn
6 */
7
8/* These are all the functions necessary to implement itimers */
9
10#include <linux/mm.h>
1da177e4
LT
11#include <linux/interrupt.h>
12#include <linux/syscalls.h>
13#include <linux/time.h>
3f07c014 14#include <linux/sched/signal.h>
32ef5517 15#include <linux/sched/cputime.h>
1da177e4 16#include <linux/posix-timers.h>
2ff678b8 17#include <linux/hrtimer.h>
3f0a525e 18#include <trace/events/timer.h>
54ad9c46 19#include <linux/compat.h>
1da177e4 20
7c0f6ba6 21#include <linux/uaccess.h>
1da177e4 22
2ff678b8
TG
23/**
24 * itimer_get_remtime - get remaining time for the timer
25 *
26 * @timer: the timer to read
27 *
28 * Returns the delta between the expiry time and now, which can be
29 * less than zero or 1usec for an pending expired timer
30 */
31static struct timeval itimer_get_remtime(struct hrtimer *timer)
1da177e4 32{
51cbb524 33 ktime_t rem = __hrtimer_get_remaining(timer, true);
1da177e4 34
2ff678b8
TG
35 /*
36 * Racy but safe: if the itimer expires after the above
37 * hrtimer_get_remtime() call but before this condition
38 * then we return 0 - which is correct.
39 */
40 if (hrtimer_active(timer)) {
2456e855
TG
41 if (rem <= 0)
42 rem = NSEC_PER_USEC;
2ff678b8 43 } else
2456e855 44 rem = 0;
2ff678b8
TG
45
46 return ktime_to_timeval(rem);
1da177e4
LT
47}
48
42c4ab41 49static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
8356b5f9 50 struct itimerval *const value)
42c4ab41 51{
858cf3a8 52 u64 val, interval;
42c4ab41
SG
53 struct cpu_itimer *it = &tsk->signal->it[clock_id];
54
55 spin_lock_irq(&tsk->sighand->siglock);
56
858cf3a8
FW
57 val = it->expires;
58 interval = it->incr;
59 if (val) {
ebd7e7fc 60 struct task_cputime cputime;
858cf3a8 61 u64 t;
42c4ab41
SG
62
63 thread_group_cputimer(tsk, &cputime);
64 if (clock_id == CPUCLOCK_PROF)
858cf3a8 65 t = cputime.utime + cputime.stime;
42c4ab41
SG
66 else
67 /* CPUCLOCK_VIRT */
858cf3a8 68 t = cputime.utime;
42c4ab41 69
858cf3a8 70 if (val < t)
42c4ab41 71 /* about to fire */
858cf3a8 72 val = TICK_NSEC;
42c4ab41 73 else
858cf3a8 74 val -= t;
42c4ab41
SG
75 }
76
77 spin_unlock_irq(&tsk->sighand->siglock);
78
858cf3a8
FW
79 value->it_value = ns_to_timeval(val);
80 value->it_interval = ns_to_timeval(interval);
42c4ab41
SG
81}
82
1da177e4
LT
83int do_getitimer(int which, struct itimerval *value)
84{
85 struct task_struct *tsk = current;
1da177e4
LT
86
87 switch (which) {
88 case ITIMER_REAL:
bc1978d4 89 spin_lock_irq(&tsk->sighand->siglock);
2ff678b8
TG
90 value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
91 value->it_interval =
92 ktime_to_timeval(tsk->signal->it_real_incr);
bc1978d4 93 spin_unlock_irq(&tsk->sighand->siglock);
1da177e4
LT
94 break;
95 case ITIMER_VIRTUAL:
42c4ab41 96 get_cpu_itimer(tsk, CPUCLOCK_VIRT, value);
1da177e4
LT
97 break;
98 case ITIMER_PROF:
42c4ab41 99 get_cpu_itimer(tsk, CPUCLOCK_PROF, value);
1da177e4
LT
100 break;
101 default:
102 return(-EINVAL);
103 }
104 return 0;
105}
106
b290ebe2 107SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value)
1da177e4
LT
108{
109 int error = -EFAULT;
110 struct itimerval get_buffer;
111
112 if (value) {
113 error = do_getitimer(which, &get_buffer);
114 if (!error &&
115 copy_to_user(value, &get_buffer, sizeof(get_buffer)))
116 error = -EFAULT;
117 }
118 return error;
119}
120
54ad9c46
AV
121#ifdef CONFIG_COMPAT
122COMPAT_SYSCALL_DEFINE2(getitimer, int, which,
123 struct compat_itimerval __user *, it)
124{
125 struct itimerval kit;
126 int error = do_getitimer(which, &kit);
127
128 if (!error && put_compat_itimerval(it, &kit))
129 error = -EFAULT;
130 return error;
131}
132#endif
133
1da177e4 134
2ff678b8
TG
135/*
136 * The timer is automagically restarted, when interval != 0
137 */
c9cb2e3d 138enum hrtimer_restart it_real_fn(struct hrtimer *timer)
1da177e4 139{
05cfb614 140 struct signal_struct *sig =
0719e370 141 container_of(timer, struct signal_struct, real_timer);
1da177e4 142
3f0a525e 143 trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0);
fea9d175 144 kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid);
2ff678b8 145
2ff678b8 146 return HRTIMER_NORESTART;
1da177e4
LT
147}
148
42c4ab41 149static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id,
8356b5f9
SG
150 const struct itimerval *const value,
151 struct itimerval *const ovalue)
42c4ab41 152{
858cf3a8 153 u64 oval, nval, ointerval, ninterval;
42c4ab41
SG
154 struct cpu_itimer *it = &tsk->signal->it[clock_id];
155
35eb7258
TG
156 /*
157 * Use the to_ktime conversion because that clamps the maximum
158 * value to KTIME_MAX and avoid multiplication overflows.
159 */
160 nval = ktime_to_ns(timeval_to_ktime(value->it_value));
161 ninterval = ktime_to_ns(timeval_to_ktime(value->it_interval));
42c4ab41
SG
162
163 spin_lock_irq(&tsk->sighand->siglock);
164
858cf3a8
FW
165 oval = it->expires;
166 ointerval = it->incr;
167 if (oval || nval) {
64861634 168 if (nval > 0)
858cf3a8
FW
169 nval += TICK_NSEC;
170 set_process_cpu_timer(tsk, clock_id, &nval, &oval);
42c4ab41
SG
171 }
172 it->expires = nval;
173 it->incr = ninterval;
3f0a525e
XG
174 trace_itimer_state(clock_id == CPUCLOCK_VIRT ?
175 ITIMER_VIRTUAL : ITIMER_PROF, value, nval);
42c4ab41
SG
176
177 spin_unlock_irq(&tsk->sighand->siglock);
178
179 if (ovalue) {
858cf3a8
FW
180 ovalue->it_value = ns_to_timeval(oval);
181 ovalue->it_interval = ns_to_timeval(ointerval);
42c4ab41
SG
182 }
183}
184
7d99b7d6
TG
185/*
186 * Returns true if the timeval is in canonical form
187 */
188#define timeval_valid(t) \
189 (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC))
190
1da177e4
LT
191int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
192{
193 struct task_struct *tsk = current;
2ff678b8
TG
194 struct hrtimer *timer;
195 ktime_t expires;
1da177e4 196
7d99b7d6
TG
197 /*
198 * Validate the timevals in value.
7d99b7d6 199 */
35bab756
AB
200 if (!timeval_valid(&value->it_value) ||
201 !timeval_valid(&value->it_interval))
202 return -EINVAL;
7d99b7d6 203
1da177e4
LT
204 switch (which) {
205 case ITIMER_REAL:
bc1978d4
TG
206again:
207 spin_lock_irq(&tsk->sighand->siglock);
2ff678b8 208 timer = &tsk->signal->real_timer;
1da177e4 209 if (ovalue) {
2ff678b8
TG
210 ovalue->it_value = itimer_get_remtime(timer);
211 ovalue->it_interval
212 = ktime_to_timeval(tsk->signal->it_real_incr);
1da177e4 213 }
a16a1c09
TG
214 /* We are sharing ->siglock with it_real_fn() */
215 if (hrtimer_try_to_cancel(timer) < 0) {
216 spin_unlock_irq(&tsk->sighand->siglock);
217 goto again;
218 }
2ff678b8 219 expires = timeval_to_ktime(value->it_value);
2456e855 220 if (expires != 0) {
8bfd9a7a
TG
221 tsk->signal->it_real_incr =
222 timeval_to_ktime(value->it_interval);
c9cb2e3d 223 hrtimer_start(timer, expires, HRTIMER_MODE_REL);
8bfd9a7a 224 } else
2456e855 225 tsk->signal->it_real_incr = 0;
8bfd9a7a 226
3f0a525e 227 trace_itimer_state(ITIMER_REAL, value, 0);
bc1978d4 228 spin_unlock_irq(&tsk->sighand->siglock);
1da177e4
LT
229 break;
230 case ITIMER_VIRTUAL:
42c4ab41 231 set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue);
1da177e4
LT
232 break;
233 case ITIMER_PROF:
42c4ab41 234 set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue);
1da177e4
LT
235 break;
236 default:
237 return -EINVAL;
238 }
239 return 0;
240}
241
74ba181e
NP
242#ifdef __ARCH_WANT_SYS_ALARM
243
c08b8a49
TG
244/**
245 * alarm_setitimer - set alarm in seconds
246 *
247 * @seconds: number of seconds until alarm
248 * 0 disables the alarm
249 *
250 * Returns the remaining time in seconds of a pending timer or 0 when
251 * the timer is not active.
252 *
253 * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid
254 * negative timeval settings which would cause immediate expiry.
255 */
74ba181e 256static unsigned int alarm_setitimer(unsigned int seconds)
c08b8a49
TG
257{
258 struct itimerval it_new, it_old;
259
260#if BITS_PER_LONG < 64
261 if (seconds > INT_MAX)
262 seconds = INT_MAX;
263#endif
264 it_new.it_value.tv_sec = seconds;
265 it_new.it_value.tv_usec = 0;
266 it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
267
268 do_setitimer(ITIMER_REAL, &it_new, &it_old);
269
270 /*
271 * We can't return 0 if we have an alarm pending ... And we'd
272 * better return too much than too little anyway
273 */
274 if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) ||
275 it_old.it_value.tv_usec >= 500000)
276 it_old.it_value.tv_sec++;
277
278 return it_old.it_value.tv_sec;
279}
280
74ba181e
NP
281/*
282 * For backwards compatibility? This can be done in libc so Alpha
283 * and all newer ports shouldn't need it.
284 */
285SYSCALL_DEFINE1(alarm, unsigned int, seconds)
286{
287 return alarm_setitimer(seconds);
288}
289
290#endif
291
362e9c07
HC
292SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value,
293 struct itimerval __user *, ovalue)
1da177e4
LT
294{
295 struct itimerval set_buffer, get_buffer;
296 int error;
297
298 if (value) {
299 if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
300 return -EFAULT;
aa2bf9bc 301 } else {
9886f444
TG
302 memset(&set_buffer, 0, sizeof(set_buffer));
303 printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer."
304 " Misfeature support will be removed\n",
305 current->comm);
aa2bf9bc 306 }
1da177e4
LT
307
308 error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
309 if (error || !ovalue)
310 return error;
311
312 if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
0719e370 313 return -EFAULT;
1da177e4
LT
314 return 0;
315}
54ad9c46
AV
316
317#ifdef CONFIG_COMPAT
318COMPAT_SYSCALL_DEFINE3(setitimer, int, which,
319 struct compat_itimerval __user *, in,
320 struct compat_itimerval __user *, out)
321{
322 struct itimerval kin, kout;
323 int error;
324
325 if (in) {
326 if (get_compat_itimerval(&kin, in))
327 return -EFAULT;
328 } else {
329 memset(&kin, 0, sizeof(kin));
330 }
331
332 error = do_setitimer(which, &kin, out ? &kout : NULL);
333 if (error || !out)
334 return error;
335 if (put_compat_itimerval(out, &kout))
336 return -EFAULT;
337 return 0;
338}
339#endif