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> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 15 | |
| 16 | #include <asm/uaccess.h> |
| 17 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 18 | /** |
| 19 | * itimer_get_remtime - get remaining time for the timer |
| 20 | * |
| 21 | * @timer: the timer to read |
| 22 | * |
| 23 | * Returns the delta between the expiry time and now, which can be |
| 24 | * less than zero or 1usec for an pending expired timer |
| 25 | */ |
| 26 | static struct timeval itimer_get_remtime(struct hrtimer *timer) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 27 | { |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 28 | ktime_t rem = hrtimer_get_remaining(timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 29 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 30 | /* |
| 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. |
| 34 | */ |
| 35 | if (hrtimer_active(timer)) { |
| 36 | if (rem.tv64 <= 0) |
| 37 | rem.tv64 = NSEC_PER_USEC; |
| 38 | } else |
| 39 | rem.tv64 = 0; |
| 40 | |
| 41 | return ktime_to_timeval(rem); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | } |
| 43 | |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame^] | 44 | static void get_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
| 45 | struct itimerval *value) |
| 46 | { |
| 47 | cputime_t cval, cinterval; |
| 48 | struct cpu_itimer *it = &tsk->signal->it[clock_id]; |
| 49 | |
| 50 | spin_lock_irq(&tsk->sighand->siglock); |
| 51 | |
| 52 | cval = it->expires; |
| 53 | cinterval = it->incr; |
| 54 | if (!cputime_eq(cval, cputime_zero)) { |
| 55 | struct task_cputime cputime; |
| 56 | cputime_t t; |
| 57 | |
| 58 | thread_group_cputimer(tsk, &cputime); |
| 59 | if (clock_id == CPUCLOCK_PROF) |
| 60 | t = cputime_add(cputime.utime, cputime.stime); |
| 61 | else |
| 62 | /* CPUCLOCK_VIRT */ |
| 63 | t = cputime.utime; |
| 64 | |
| 65 | if (cputime_le(cval, t)) |
| 66 | /* about to fire */ |
| 67 | cval = jiffies_to_cputime(1); |
| 68 | else |
| 69 | cval = cputime_sub(cval, t); |
| 70 | } |
| 71 | |
| 72 | spin_unlock_irq(&tsk->sighand->siglock); |
| 73 | |
| 74 | cputime_to_timeval(cval, &value->it_value); |
| 75 | cputime_to_timeval(cinterval, &value->it_interval); |
| 76 | } |
| 77 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | int do_getitimer(int which, struct itimerval *value) |
| 79 | { |
| 80 | struct task_struct *tsk = current; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | |
| 82 | switch (which) { |
| 83 | case ITIMER_REAL: |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 84 | spin_lock_irq(&tsk->sighand->siglock); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 85 | value->it_value = itimer_get_remtime(&tsk->signal->real_timer); |
| 86 | value->it_interval = |
| 87 | ktime_to_timeval(tsk->signal->it_real_incr); |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 88 | spin_unlock_irq(&tsk->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | break; |
| 90 | case ITIMER_VIRTUAL: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame^] | 91 | get_cpu_itimer(tsk, CPUCLOCK_VIRT, value); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 92 | break; |
| 93 | case ITIMER_PROF: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame^] | 94 | get_cpu_itimer(tsk, CPUCLOCK_PROF, value); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 95 | break; |
| 96 | default: |
| 97 | return(-EINVAL); |
| 98 | } |
| 99 | return 0; |
| 100 | } |
| 101 | |
Heiko Carstens | b290ebe | 2009-01-14 14:14:06 +0100 | [diff] [blame] | 102 | SYSCALL_DEFINE2(getitimer, int, which, struct itimerval __user *, value) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 103 | { |
| 104 | int error = -EFAULT; |
| 105 | struct itimerval get_buffer; |
| 106 | |
| 107 | if (value) { |
| 108 | error = do_getitimer(which, &get_buffer); |
| 109 | if (!error && |
| 110 | copy_to_user(value, &get_buffer, sizeof(get_buffer))) |
| 111 | error = -EFAULT; |
| 112 | } |
| 113 | return error; |
| 114 | } |
| 115 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 117 | /* |
| 118 | * The timer is automagically restarted, when interval != 0 |
| 119 | */ |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 120 | enum hrtimer_restart it_real_fn(struct hrtimer *timer) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | { |
Roman Zippel | 05cfb61 | 2006-03-26 01:38:12 -0800 | [diff] [blame] | 122 | struct signal_struct *sig = |
Daniel Walker | 0719e37 | 2007-10-18 03:06:11 -0700 | [diff] [blame] | 123 | container_of(timer, struct signal_struct, real_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | |
Oleg Nesterov | fea9d17 | 2008-02-08 04:19:19 -0800 | [diff] [blame] | 125 | kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 126 | |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 127 | return HRTIMER_NORESTART; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | } |
| 129 | |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame^] | 130 | static void set_cpu_itimer(struct task_struct *tsk, unsigned int clock_id, |
| 131 | struct itimerval *value, struct itimerval *ovalue) |
| 132 | { |
| 133 | cputime_t cval, cinterval, nval, ninterval; |
| 134 | struct cpu_itimer *it = &tsk->signal->it[clock_id]; |
| 135 | |
| 136 | nval = timeval_to_cputime(&value->it_value); |
| 137 | ninterval = timeval_to_cputime(&value->it_interval); |
| 138 | |
| 139 | spin_lock_irq(&tsk->sighand->siglock); |
| 140 | |
| 141 | cval = it->expires; |
| 142 | cinterval = it->incr; |
| 143 | if (!cputime_eq(cval, cputime_zero) || |
| 144 | !cputime_eq(nval, cputime_zero)) { |
| 145 | if (cputime_gt(nval, cputime_zero)) |
| 146 | nval = cputime_add(nval, jiffies_to_cputime(1)); |
| 147 | set_process_cpu_timer(tsk, clock_id, &nval, &cval); |
| 148 | } |
| 149 | it->expires = nval; |
| 150 | it->incr = ninterval; |
| 151 | |
| 152 | spin_unlock_irq(&tsk->sighand->siglock); |
| 153 | |
| 154 | if (ovalue) { |
| 155 | cputime_to_timeval(cval, &ovalue->it_value); |
| 156 | cputime_to_timeval(cinterval, &ovalue->it_interval); |
| 157 | } |
| 158 | } |
| 159 | |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 160 | /* |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 161 | * Returns true if the timeval is in canonical form |
| 162 | */ |
| 163 | #define timeval_valid(t) \ |
| 164 | (((t)->tv_sec >= 0) && (((unsigned long) (t)->tv_usec) < USEC_PER_SEC)) |
| 165 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 166 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) |
| 167 | { |
| 168 | struct task_struct *tsk = current; |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 169 | struct hrtimer *timer; |
| 170 | ktime_t expires; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 172 | /* |
| 173 | * Validate the timevals in value. |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 174 | */ |
Adrian Bunk | 35bab75 | 2007-05-08 00:30:49 -0700 | [diff] [blame] | 175 | if (!timeval_valid(&value->it_value) || |
| 176 | !timeval_valid(&value->it_interval)) |
| 177 | return -EINVAL; |
Thomas Gleixner | 7d99b7d | 2006-03-25 03:06:35 -0800 | [diff] [blame] | 178 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | switch (which) { |
| 180 | case ITIMER_REAL: |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 181 | again: |
| 182 | spin_lock_irq(&tsk->sighand->siglock); |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 183 | timer = &tsk->signal->real_timer; |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 184 | if (ovalue) { |
| 185 | ovalue->it_value = itimer_get_remtime(timer); |
| 186 | ovalue->it_interval |
| 187 | = ktime_to_timeval(tsk->signal->it_real_incr); |
Oleg Nesterov | f01b1b0 | 2005-06-28 20:44:47 -0700 | [diff] [blame] | 188 | } |
Thomas Gleixner | a16a1c0 | 2006-02-01 03:05:09 -0800 | [diff] [blame] | 189 | /* We are sharing ->siglock with it_real_fn() */ |
| 190 | if (hrtimer_try_to_cancel(timer) < 0) { |
| 191 | spin_unlock_irq(&tsk->sighand->siglock); |
| 192 | goto again; |
| 193 | } |
Thomas Gleixner | 2ff678b | 2006-01-09 20:52:34 -0800 | [diff] [blame] | 194 | expires = timeval_to_ktime(value->it_value); |
Thomas Gleixner | 8bfd9a7 | 2007-02-16 01:28:12 -0800 | [diff] [blame] | 195 | if (expires.tv64 != 0) { |
| 196 | tsk->signal->it_real_incr = |
| 197 | timeval_to_ktime(value->it_interval); |
Thomas Gleixner | c9cb2e3 | 2007-02-16 01:27:49 -0800 | [diff] [blame] | 198 | hrtimer_start(timer, expires, HRTIMER_MODE_REL); |
Thomas Gleixner | 8bfd9a7 | 2007-02-16 01:28:12 -0800 | [diff] [blame] | 199 | } else |
| 200 | tsk->signal->it_real_incr.tv64 = 0; |
| 201 | |
Thomas Gleixner | bc1978d | 2006-02-01 03:05:08 -0800 | [diff] [blame] | 202 | spin_unlock_irq(&tsk->sighand->siglock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | break; |
| 204 | case ITIMER_VIRTUAL: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame^] | 205 | set_cpu_itimer(tsk, CPUCLOCK_VIRT, value, ovalue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 206 | break; |
| 207 | case ITIMER_PROF: |
Stanislaw Gruszka | 42c4ab4 | 2009-07-29 12:15:26 +0200 | [diff] [blame^] | 208 | set_cpu_itimer(tsk, CPUCLOCK_PROF, value, ovalue); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | break; |
| 210 | default: |
| 211 | return -EINVAL; |
| 212 | } |
| 213 | return 0; |
| 214 | } |
| 215 | |
Thomas Gleixner | c08b8a4 | 2006-03-25 03:06:33 -0800 | [diff] [blame] | 216 | /** |
| 217 | * alarm_setitimer - set alarm in seconds |
| 218 | * |
| 219 | * @seconds: number of seconds until alarm |
| 220 | * 0 disables the alarm |
| 221 | * |
| 222 | * Returns the remaining time in seconds of a pending timer or 0 when |
| 223 | * the timer is not active. |
| 224 | * |
| 225 | * On 32 bit machines the seconds value is limited to (INT_MAX/2) to avoid |
| 226 | * negative timeval settings which would cause immediate expiry. |
| 227 | */ |
| 228 | unsigned int alarm_setitimer(unsigned int seconds) |
| 229 | { |
| 230 | struct itimerval it_new, it_old; |
| 231 | |
| 232 | #if BITS_PER_LONG < 64 |
| 233 | if (seconds > INT_MAX) |
| 234 | seconds = INT_MAX; |
| 235 | #endif |
| 236 | it_new.it_value.tv_sec = seconds; |
| 237 | it_new.it_value.tv_usec = 0; |
| 238 | it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0; |
| 239 | |
| 240 | do_setitimer(ITIMER_REAL, &it_new, &it_old); |
| 241 | |
| 242 | /* |
| 243 | * We can't return 0 if we have an alarm pending ... And we'd |
| 244 | * better return too much than too little anyway |
| 245 | */ |
| 246 | if ((!it_old.it_value.tv_sec && it_old.it_value.tv_usec) || |
| 247 | it_old.it_value.tv_usec >= 500000) |
| 248 | it_old.it_value.tv_sec++; |
| 249 | |
| 250 | return it_old.it_value.tv_sec; |
| 251 | } |
| 252 | |
Heiko Carstens | 362e9c0 | 2009-01-14 14:14:07 +0100 | [diff] [blame] | 253 | SYSCALL_DEFINE3(setitimer, int, which, struct itimerval __user *, value, |
| 254 | struct itimerval __user *, ovalue) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 255 | { |
| 256 | struct itimerval set_buffer, get_buffer; |
| 257 | int error; |
| 258 | |
| 259 | if (value) { |
| 260 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) |
| 261 | return -EFAULT; |
| 262 | } else |
| 263 | memset((char *) &set_buffer, 0, sizeof(set_buffer)); |
| 264 | |
| 265 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); |
| 266 | if (error || !ovalue) |
| 267 | return error; |
| 268 | |
| 269 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) |
Daniel Walker | 0719e37 | 2007-10-18 03:06:11 -0700 | [diff] [blame] | 270 | return -EFAULT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | return 0; |
| 272 | } |