Commit | Line | Data |
---|---|---|
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 LT |
16 | |
17 | #include <asm/uaccess.h> | |
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)) { | |
37 | if (rem.tv64 <= 0) | |
38 | rem.tv64 = NSEC_PER_USEC; | |
39 | } else | |
40 | rem.tv64 = 0; | |
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 SG |
47 | { |
48 | cputime_t cval, cinterval; | |
49 | struct cpu_itimer *it = &tsk->signal->it[clock_id]; | |
50 | ||
51 | spin_lock_irq(&tsk->sighand->siglock); | |
52 | ||
53 | cval = it->expires; | |
54 | cinterval = it->incr; | |
64861634 | 55 | if (cval) { |
42c4ab41 SG |
56 | struct task_cputime cputime; |
57 | cputime_t t; | |
58 | ||
59 | thread_group_cputimer(tsk, &cputime); | |
60 | if (clock_id == CPUCLOCK_PROF) | |
64861634 | 61 | t = cputime.utime + cputime.stime; |
42c4ab41 SG |
62 | else |
63 | /* CPUCLOCK_VIRT */ | |
64 | t = cputime.utime; | |
65 | ||
64861634 | 66 | if (cval < t) |
42c4ab41 | 67 | /* about to fire */ |
a42548a1 | 68 | cval = cputime_one_jiffy; |
42c4ab41 | 69 | else |
64861634 | 70 | cval = cval - t; |
42c4ab41 SG |
71 | } |
72 | ||
73 | spin_unlock_irq(&tsk->sighand->siglock); | |
74 | ||
75 | cputime_to_timeval(cval, &value->it_value); | |
76 | cputime_to_timeval(cinterval, &value->it_interval); | |
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 | ||
8356b5f9 SG |
132 | static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns) |
133 | { | |
134 | struct timespec ts; | |
135 | s64 cpu_ns; | |
136 | ||
137 | cputime_to_timespec(ct, &ts); | |
138 | cpu_ns = timespec_to_ns(&ts); | |
139 | ||
140 | return (cpu_ns <= real_ns) ? 0 : cpu_ns - real_ns; | |
141 | } | |
142 | ||
42c4ab41 | 143 | static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
8356b5f9 SG |
144 | const struct itimerval *const value, |
145 | struct itimerval *const ovalue) | |
42c4ab41 | 146 | { |
8356b5f9 SG |
147 | cputime_t cval, nval, cinterval, ninterval; |
148 | s64 ns_ninterval, ns_nval; | |
8747d793 | 149 | u32 error, incr_error; |
42c4ab41 SG |
150 | struct cpu_itimer *it = &tsk->signal->it[clock_id]; |
151 | ||
152 | nval = timeval_to_cputime(&value->it_value); | |
8356b5f9 | 153 | ns_nval = timeval_to_ns(&value->it_value); |
42c4ab41 | 154 | ninterval = timeval_to_cputime(&value->it_interval); |
8356b5f9 SG |
155 | ns_ninterval = timeval_to_ns(&value->it_interval); |
156 | ||
8747d793 SG |
157 | error = cputime_sub_ns(nval, ns_nval); |
158 | incr_error = cputime_sub_ns(ninterval, ns_ninterval); | |
42c4ab41 SG |
159 | |
160 | spin_lock_irq(&tsk->sighand->siglock); | |
161 | ||
162 | cval = it->expires; | |
163 | cinterval = it->incr; | |
64861634 MS |
164 | if (cval || nval) { |
165 | if (nval > 0) | |
166 | nval += cputime_one_jiffy; | |
42c4ab41 SG |
167 | set_process_cpu_timer(tsk, clock_id, &nval, &cval); |
168 | } | |
169 | it->expires = nval; | |
170 | it->incr = ninterval; | |
8747d793 SG |
171 | it->error = error; |
172 | it->incr_error = incr_error; | |
3f0a525e XG |
173 | trace_itimer_state(clock_id == CPUCLOCK_VIRT ? |
174 | ITIMER_VIRTUAL : ITIMER_PROF, value, nval); | |
42c4ab41 SG |
175 | |
176 | spin_unlock_irq(&tsk->sighand->siglock); | |
177 | ||
178 | if (ovalue) { | |
179 | cputime_to_timeval(cval, &ovalue->it_value); | |
180 | cputime_to_timeval(cinterval, &ovalue->it_interval); | |
181 | } | |
182 | } | |
183 | ||
7d99b7d6 TG |
184 | /* |
185 | * Returns true if the timeval is in canonical form | |
186 | */ | |
187 | #define timeval_valid(t) \ | |
188 | (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC)) | |
189 | ||
1da177e4 LT |
190 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) |
191 | { | |
192 | struct task_struct *tsk = current; | |
2ff678b8 TG |
193 | struct hrtimer *timer; |
194 | ktime_t expires; | |
1da177e4 | 195 | |
7d99b7d6 TG |
196 | /* |
197 | * Validate the timevals in value. | |
7d99b7d6 | 198 | */ |
35bab756 AB |
199 | if (!timeval_valid(&value->it_value) || |
200 | !timeval_valid(&value->it_interval)) | |
201 | return -EINVAL; | |
7d99b7d6 | 202 | |
1da177e4 LT |
203 | switch (which) { |
204 | case ITIMER_REAL: | |
bc1978d4 TG |
205 | again: |
206 | spin_lock_irq(&tsk->sighand->siglock); | |
2ff678b8 | 207 | timer = &tsk->signal->real_timer; |
1da177e4 | 208 | if (ovalue) { |
2ff678b8 TG |
209 | ovalue->it_value = itimer_get_remtime(timer); |
210 | ovalue->it_interval | |
211 | = ktime_to_timeval(tsk->signal->it_real_incr); | |
1da177e4 | 212 | } |
a16a1c09 TG |
213 | /* We are sharing ->siglock with it_real_fn() */ |
214 | if (hrtimer_try_to_cancel(timer) < 0) { | |
215 | spin_unlock_irq(&tsk->sighand->siglock); | |
216 | goto again; | |
217 | } | |
2ff678b8 | 218 | expires = timeval_to_ktime(value->it_value); |
8bfd9a7a TG |
219 | if (expires.tv64 != 0) { |
220 | tsk->signal->it_real_incr = | |
221 | timeval_to_ktime(value->it_interval); | |
c9cb2e3d | 222 | hrtimer_start(timer, expires, HRTIMER_MODE_REL); |
8bfd9a7a TG |
223 | } else |
224 | tsk->signal->it_real_incr.tv64 = 0; | |
225 | ||
3f0a525e | 226 | trace_itimer_state(ITIMER_REAL, value, 0); |
bc1978d4 | 227 | spin_unlock_irq(&tsk->sighand->siglock); |
1da177e4 LT |
228 | break; |
229 | case ITIMER_VIRTUAL: | |
42c4ab41 | 230 | set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue); |
1da177e4 LT |
231 | break; |
232 | case ITIMER_PROF: | |
42c4ab41 | 233 | set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue); |
1da177e4 LT |
234 | break; |
235 | default: | |
236 | return -EINVAL; | |
237 | } | |
238 | return 0; | |
239 | } | |
240 | ||
c08b8a49 TG |
241 | /** |
242 | * alarm_setitimer - set alarm in seconds | |
243 | * | |
244 | * @seconds: number of seconds until alarm | |
245 | * 0 disables the alarm | |
246 | * | |
247 | * Returns the remaining time in seconds of a pending timer or 0 when | |
248 | * the timer is not active. | |
249 | * | |
250 | * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid | |
251 | * negative timeval settings which would cause immediate expiry. | |
252 | */ | |
253 | unsigned int alarm_setitimer(unsigned int seconds) | |
254 | { | |
255 | struct itimerval it_new, it_old; | |
256 | ||
257 | #if BITS_PER_LONG < 64 | |
258 | if (seconds > INT_MAX) | |
259 | seconds = INT_MAX; | |
260 | #endif | |
261 | it_new.it_value.tv_sec = seconds; | |
262 | it_new.it_value.tv_usec = 0; | |
263 | it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; | |
264 | ||
265 | do_setitimer(ITIMER_REAL, &it_new, &it_old); | |
266 | ||
267 | /* | |
268 | * We can't return 0 if we have an alarm pending ... And we'd | |
269 | * better return too much than too little anyway | |
270 | */ | |
271 | if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) || | |
272 | it_old.it_value.tv_usec >= 500000) | |
273 | it_old.it_value.tv_sec++; | |
274 | ||
275 | return it_old.it_value.tv_sec; | |
276 | } | |
277 | ||
362e9c07 HC |
278 | SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, |
279 | struct itimerval __user *, ovalue) | |
1da177e4 LT |
280 | { |
281 | struct itimerval set_buffer, get_buffer; | |
282 | int error; | |
283 | ||
284 | if (value) { | |
285 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) | |
286 | return -EFAULT; | |
aa2bf9bc | 287 | } else { |
9886f444 TG |
288 | memset(&set_buffer, 0, sizeof(set_buffer)); |
289 | printk_once(KERN_WARNING "%s calls setitimer() with new_value NULL pointer." | |
290 | " Misfeature support will be removed\n", | |
291 | current->comm); | |
aa2bf9bc | 292 | } |
1da177e4 LT |
293 | |
294 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); | |
295 | if (error || !ovalue) | |
296 | return error; | |
297 | ||
298 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) | |
0719e370 | 299 | return -EFAULT; |
1da177e4 LT |
300 | return 0; |
301 | } |