Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 10 | #include <linux/interrupt.h> |
| 11 | #include <linux/syscalls.h> |
| 12 | #include <linux/time.h> |
| 13 | #include <linux/posix-timers.h> |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 14 | #include <linux/hrtimer.h> |
Xiao Guangrong | 3f0a525 | 2009-08-10 10:52:30 +0800 | [diff] [blame] | 15 | #include <trace/events/timer.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | #include <asm/uaccess.h> |
| 18 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 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) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | { |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 29 | ktime_t rem = hrtimer_get_remaining(timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 30 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 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); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | } |
| 44 | |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 45 | static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
Stanislaw Gruszka | 8356b5f | 2009-07-29 12:15:27 +0200 | [diff] [blame] | 46 | struct itimerval *const value) |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 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; |
| 55 | if (!cputime_eq(cval, cputime_zero)) { |
| 56 | struct task_cputime cputime; |
| 57 | cputime_t t; |
| 58 | |
| 59 | thread_group_cputimer(tsk, &cputime); |
| 60 | if (clock_id == CPUCLOCK_PROF) |
| 61 | t = cputime_add(cputime.utime, cputime.stime); |
| 62 | else |
| 63 | /* CPUCLOCK_VIRT */ |
| 64 | t = cputime.utime; |
| 65 | |
| 66 | if (cputime_le(cval, t)) |
| 67 | /* about to fire */ |
Stanislaw Gruszka | a42548a | 2009-07-29 12:15:29 +0200 | [diff] [blame] | 68 | cval = cputime_one_jiffy; |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 69 | else |
| 70 | cval = cputime_sub(cval, t); |
| 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | int do_getitimer(int which, struct itimerval *value) |
| 80 | { |
| 81 | struct task_struct *tsk = current; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
| 83 | switch (which) { |
| 84 | case ITIMER_REAL: |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 85 | spin_lock_irq(&tsk->sighand->siglock); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 86 | value->it_value = itimer_get_remtime(&tsk->signal->real_timer); |
| 87 | value->it_interval = |
| 88 | ktime_to_timeval(tsk->signal->it_real_incr); |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 89 | spin_unlock_irq(&tsk->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | break; |
| 91 | case ITIMER_VIRTUAL: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 92 | get_cpu_itimer(tsk, CPUCLOCK_VIRT, value); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 93 | break; |
| 94 | case ITIMER_PROF: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 95 | get_cpu_itimer(tsk, CPUCLOCK_PROF, value); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 96 | break; |
| 97 | default: |
| 98 | return(-EINVAL); |
| 99 | } |
| 100 | return 0; |
| 101 | } |
| 102 | |
Heiko Carstens | b290ebe | 2009-01-14 14:14:06 +0100 | [diff] [blame] | 103 | SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 117 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 118 | /* |
| 119 | * The timer is automagically restarted, when interval != 0 |
| 120 | */ |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 121 | enum hrtimer_restart it_real_fn(struct hrtimer *timer) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 122 | { |
Roman Zippel | 05cfb61 | 2006-03-26 01:38:12 -0800 | [diff] [blame] | 123 | struct signal_struct *sig = |
Daniel Walker | 0719e37 | 2007-10-18 03:06:11 -0700 | [diff] [blame] | 124 | container_of(timer, struct signal_struct, real_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 125 | |
Xiao Guangrong | 3f0a525 | 2009-08-10 10:52:30 +0800 | [diff] [blame] | 126 | trace_itimer_expire(ITIMER_REAL, sig->leader_pid, 0); |
Oleg Nesterov | fea9d17 | 2008-02-08 04:19:19 -0800 | [diff] [blame] | 127 | kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 129 | return HRTIMER_NORESTART; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | } |
| 131 | |
Stanislaw Gruszka | 8356b5f | 2009-07-29 12:15:27 +0200 | [diff] [blame] | 132 | static inline u32 cputime_sub_ns(cputime_t ct, s64 real_ns) |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 133 | { |
Stanislaw Gruszka | 8356b5f | 2009-07-29 12:15:27 +0200 | [diff] [blame] | 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 | |
| 143 | static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
| 144 | const struct itimerval *const value, |
| 145 | struct itimerval *const ovalue) |
| 146 | { |
| 147 | cputime_t cval, nval, cinterval, ninterval; |
| 148 | s64 ns_ninterval, ns_nval; |
Stanislaw Gruszka | 8747d79 | 2009-11-17 14:14:12 -0800 | [diff] [blame] | 149 | u32 error, incr_error; |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 150 | struct cpu_itimer *it = &tsk->signal->it[clock_id]; |
| 151 | |
| 152 | nval = timeval_to_cputime(&value->it_value); |
Stanislaw Gruszka | 8356b5f | 2009-07-29 12:15:27 +0200 | [diff] [blame] | 153 | ns_nval = timeval_to_ns(&value->it_value); |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 154 | ninterval = timeval_to_cputime(&value->it_interval); |
Stanislaw Gruszka | 8356b5f | 2009-07-29 12:15:27 +0200 | [diff] [blame] | 155 | ns_ninterval = timeval_to_ns(&value->it_interval); |
| 156 | |
Stanislaw Gruszka | 8747d79 | 2009-11-17 14:14:12 -0800 | [diff] [blame] | 157 | error = cputime_sub_ns(nval, ns_nval); |
| 158 | incr_error = cputime_sub_ns(ninterval, ns_ninterval); |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 159 | |
| 160 | spin_lock_irq(&tsk->sighand->siglock); |
| 161 | |
| 162 | cval = it->expires; |
| 163 | cinterval = it->incr; |
| 164 | if (!cputime_eq(cval, cputime_zero) || |
| 165 | !cputime_eq(nval, cputime_zero)) { |
| 166 | if (cputime_gt(nval, cputime_zero)) |
Stanislaw Gruszka | a42548a | 2009-07-29 12:15:29 +0200 | [diff] [blame] | 167 | nval = cputime_add(nval, cputime_one_jiffy); |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 168 | set_process_cpu_timer(tsk, clock_id, &nval, &cval); |
| 169 | } |
| 170 | it->expires = nval; |
| 171 | it->incr = ninterval; |
Stanislaw Gruszka | 8747d79 | 2009-11-17 14:14:12 -0800 | [diff] [blame] | 172 | it->error = error; |
| 173 | it->incr_error = incr_error; |
Xiao Guangrong | 3f0a525 | 2009-08-10 10:52:30 +0800 | [diff] [blame] | 174 | trace_itimer_state(clock_id == CPUCLOCK_VIRT ? |
| 175 | ITIMER_VIRTUAL : ITIMER_PROF, value, nval); |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 176 | |
| 177 | spin_unlock_irq(&tsk->sighand->siglock); |
| 178 | |
| 179 | if (ovalue) { |
| 180 | cputime_to_timeval(cval, &ovalue->it_value); |
| 181 | cputime_to_timeval(cinterval, &ovalue->it_interval); |
| 182 | } |
| 183 | } |
| 184 | |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 185 | /* |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) |
| 192 | { |
| 193 | struct task_struct *tsk = current; |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 194 | struct hrtimer *timer; |
| 195 | ktime_t expires; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 197 | /* |
| 198 | * Validate the timevals in value. |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 199 | */ |
Adrian Bunk | 35bab75 | 2007-05-08 00:30:49 -0700 | [diff] [blame] | 200 | if (!timeval_valid(&value->it_value) || |
| 201 | !timeval_valid(&value->it_interval)) |
| 202 | return -EINVAL; |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 203 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | switch (which) { |
| 205 | case ITIMER_REAL: |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 206 | again: |
| 207 | spin_lock_irq(&tsk->sighand->siglock); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 208 | timer = &tsk->signal->real_timer; |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 209 | if (ovalue) { |
| 210 | ovalue->it_value = itimer_get_remtime(timer); |
| 211 | ovalue->it_interval |
| 212 | = ktime_to_timeval(tsk->signal->it_real_incr); |
Oleg Nesterov | f01b1b0 | 2005-06-28 20:44:47 -0700 | [diff] [blame] | 213 | } |
Thomas Gleixner | a16a1c0 | 2006-02-01 03:05:09 -0800 | [diff] [blame] | 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 | } |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 219 | expires = timeval_to_ktime(value->it_value); |
Thomas Gleixner | 8bfd9a7 | 2007-02-16 01:28:12 -0800 | [diff] [blame] | 220 | if (expires.tv64 != 0) { |
| 221 | tsk->signal->it_real_incr = |
| 222 | timeval_to_ktime(value->it_interval); |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 223 | hrtimer_start(timer, expires, HRTIMER_MODE_REL); |
Thomas Gleixner | 8bfd9a7 | 2007-02-16 01:28:12 -0800 | [diff] [blame] | 224 | } else |
| 225 | tsk->signal->it_real_incr.tv64 = 0; |
| 226 | |
Xiao Guangrong | 3f0a525 | 2009-08-10 10:52:30 +0800 | [diff] [blame] | 227 | trace_itimer_state(ITIMER_REAL, value, 0); |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 228 | spin_unlock_irq(&tsk->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | break; |
| 230 | case ITIMER_VIRTUAL: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 231 | set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 232 | break; |
| 233 | case ITIMER_PROF: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame] | 234 | set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | break; |
| 236 | default: |
| 237 | return -EINVAL; |
| 238 | } |
| 239 | return 0; |
| 240 | } |
| 241 | |
Thomas Gleixner | c08b8a4 | 2006-03-25 03:06:33 -0800 | [diff] [blame] | 242 | /** |
| 243 | * alarm_setitimer - set alarm in seconds |
| 244 | * |
| 245 | * @seconds: number of seconds until alarm |
| 246 | * 0 disables the alarm |
| 247 | * |
| 248 | * Returns the remaining time in seconds of a pending timer or 0 when |
| 249 | * the timer is not active. |
| 250 | * |
| 251 | * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid |
| 252 | * negative timeval settings which would cause immediate expiry. |
| 253 | */ |
| 254 | unsigned int alarm_setitimer(unsigned int seconds) |
| 255 | { |
| 256 | struct itimerval it_new, it_old; |
| 257 | |
| 258 | #if BITS_PER_LONG < 64 |
| 259 | if (seconds > INT_MAX) |
| 260 | seconds = INT_MAX; |
| 261 | #endif |
| 262 | it_new.it_value.tv_sec = seconds; |
| 263 | it_new.it_value.tv_usec = 0; |
| 264 | it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; |
| 265 | |
| 266 | do_setitimer(ITIMER_REAL, &it_new, &it_old); |
| 267 | |
| 268 | /* |
| 269 | * We can't return 0 if we have an alarm pending ... And we'd |
| 270 | * better return too much than too little anyway |
| 271 | */ |
| 272 | if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) || |
| 273 | it_old.it_value.tv_usec >= 500000) |
| 274 | it_old.it_value.tv_sec++; |
| 275 | |
| 276 | return it_old.it_value.tv_sec; |
| 277 | } |
| 278 | |
Heiko Carstens | 362e9c0 | 2009-01-14 14:14:07 +0100 | [diff] [blame] | 279 | SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, |
| 280 | struct itimerval __user *, ovalue) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | { |
| 282 | struct itimerval set_buffer, get_buffer; |
| 283 | int error; |
| 284 | |
| 285 | if (value) { |
| 286 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) |
| 287 | return -EFAULT; |
| 288 | } else |
| 289 | memset((char *) &set_buffer, 0, sizeof(set_buffer)); |
| 290 | |
| 291 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); |
| 292 | if (error || !ovalue) |
| 293 | return error; |
| 294 | |
| 295 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) |
Daniel Walker | 0719e37 | 2007-10-18 03:06:11 -0700 | [diff] [blame] | 296 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 297 | return 0; |
| 298 | } |