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