[PATCH] hrtimers: fixup itimer conversion
[linux-3.10.git] / kernel / itimer.c
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>
10 #include <linux/smp_lock.h>
11 #include <linux/interrupt.h>
12 #include <linux/syscalls.h>
13 #include <linux/time.h>
14 #include <linux/posix-timers.h>
15 #include <linux/hrtimer.h>
16
17 #include <asm/uaccess.h>
18
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)
28 {
29         ktime_t rem = hrtimer_get_remaining(timer);
30
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);
43 }
44
45 int do_getitimer(int which, struct itimerval *value)
46 {
47         struct task_struct *tsk = current;
48         cputime_t cinterval, cval;
49
50         switch (which) {
51         case ITIMER_REAL:
52                 spin_lock_irq(&tsk->sighand->siglock);
53                 value->it_value = itimer_get_remtime(&tsk->signal->real_timer);
54                 value->it_interval =
55                         ktime_to_timeval(tsk->signal->it_real_incr);
56                 spin_unlock_irq(&tsk->sighand->siglock);
57                 break;
58         case ITIMER_VIRTUAL:
59                 read_lock(&tasklist_lock);
60                 spin_lock_irq(&tsk->sighand->siglock);
61                 cval = tsk->signal->it_virt_expires;
62                 cinterval = tsk->signal->it_virt_incr;
63                 if (!cputime_eq(cval, cputime_zero)) {
64                         struct task_struct *t = tsk;
65                         cputime_t utime = tsk->signal->utime;
66                         do {
67                                 utime = cputime_add(utime, t->utime);
68                                 t = next_thread(t);
69                         } while (t != tsk);
70                         if (cputime_le(cval, utime)) { /* about to fire */
71                                 cval = jiffies_to_cputime(1);
72                         } else {
73                                 cval = cputime_sub(cval, utime);
74                         }
75                 }
76                 spin_unlock_irq(&tsk->sighand->siglock);
77                 read_unlock(&tasklist_lock);
78                 cputime_to_timeval(cval, &value->it_value);
79                 cputime_to_timeval(cinterval, &value->it_interval);
80                 break;
81         case ITIMER_PROF:
82                 read_lock(&tasklist_lock);
83                 spin_lock_irq(&tsk->sighand->siglock);
84                 cval = tsk->signal->it_prof_expires;
85                 cinterval = tsk->signal->it_prof_incr;
86                 if (!cputime_eq(cval, cputime_zero)) {
87                         struct task_struct *t = tsk;
88                         cputime_t ptime = cputime_add(tsk->signal->utime,
89                                                       tsk->signal->stime);
90                         do {
91                                 ptime = cputime_add(ptime,
92                                                     cputime_add(t->utime,
93                                                                 t->stime));
94                                 t = next_thread(t);
95                         } while (t != tsk);
96                         if (cputime_le(cval, ptime)) { /* about to fire */
97                                 cval = jiffies_to_cputime(1);
98                         } else {
99                                 cval = cputime_sub(cval, ptime);
100                         }
101                 }
102                 spin_unlock_irq(&tsk->sighand->siglock);
103                 read_unlock(&tasklist_lock);
104                 cputime_to_timeval(cval, &value->it_value);
105                 cputime_to_timeval(cinterval, &value->it_interval);
106                 break;
107         default:
108                 return(-EINVAL);
109         }
110         return 0;
111 }
112
113 asmlinkage long sys_getitimer(int which, struct itimerval __user *value)
114 {
115         int error = -EFAULT;
116         struct itimerval get_buffer;
117
118         if (value) {
119                 error = do_getitimer(which, &get_buffer);
120                 if (!error &&
121                     copy_to_user(value, &get_buffer, sizeof(get_buffer)))
122                         error = -EFAULT;
123         }
124         return error;
125 }
126
127
128 /*
129  * The timer is automagically restarted, when interval != 0
130  */
131 int it_real_fn(void *data)
132 {
133         struct task_struct *tsk = (struct task_struct *) data;
134
135         send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk);
136
137         if (tsk->signal->it_real_incr.tv64 != 0) {
138                 hrtimer_forward(&tsk->signal->real_timer,
139                                tsk->signal->it_real_incr);
140
141                 return HRTIMER_RESTART;
142         }
143         return HRTIMER_NORESTART;
144 }
145
146 int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue)
147 {
148         struct task_struct *tsk = current;
149         struct hrtimer *timer;
150         ktime_t expires;
151         cputime_t cval, cinterval, nval, ninterval;
152
153         switch (which) {
154         case ITIMER_REAL:
155 again:
156                 spin_lock_irq(&tsk->sighand->siglock);
157                 timer = &tsk->signal->real_timer;
158                 /* We are sharing ->siglock with it_real_fn() */
159                 if (hrtimer_try_to_cancel(timer) < 0) {
160                         spin_unlock_irq(&tsk->sighand->siglock);
161                         goto again;
162                 }
163                 if (ovalue) {
164                         ovalue->it_value = itimer_get_remtime(timer);
165                         ovalue->it_interval
166                                 = ktime_to_timeval(tsk->signal->it_real_incr);
167                 }
168                 tsk->signal->it_real_incr =
169                         timeval_to_ktime(value->it_interval);
170                 expires = timeval_to_ktime(value->it_value);
171                 if (expires.tv64 != 0)
172                         hrtimer_start(timer, expires, HRTIMER_REL);
173                 spin_unlock_irq(&tsk->sighand->siglock);
174                 break;
175         case ITIMER_VIRTUAL:
176                 nval = timeval_to_cputime(&value->it_value);
177                 ninterval = timeval_to_cputime(&value->it_interval);
178                 read_lock(&tasklist_lock);
179                 spin_lock_irq(&tsk->sighand->siglock);
180                 cval = tsk->signal->it_virt_expires;
181                 cinterval = tsk->signal->it_virt_incr;
182                 if (!cputime_eq(cval, cputime_zero) ||
183                     !cputime_eq(nval, cputime_zero)) {
184                         if (cputime_gt(nval, cputime_zero))
185                                 nval = cputime_add(nval,
186                                                    jiffies_to_cputime(1));
187                         set_process_cpu_timer(tsk, CPUCLOCK_VIRT,
188                                               &nval, &cval);
189                 }
190                 tsk->signal->it_virt_expires = nval;
191                 tsk->signal->it_virt_incr = ninterval;
192                 spin_unlock_irq(&tsk->sighand->siglock);
193                 read_unlock(&tasklist_lock);
194                 if (ovalue) {
195                         cputime_to_timeval(cval, &ovalue->it_value);
196                         cputime_to_timeval(cinterval, &ovalue->it_interval);
197                 }
198                 break;
199         case ITIMER_PROF:
200                 nval = timeval_to_cputime(&value->it_value);
201                 ninterval = timeval_to_cputime(&value->it_interval);
202                 read_lock(&tasklist_lock);
203                 spin_lock_irq(&tsk->sighand->siglock);
204                 cval = tsk->signal->it_prof_expires;
205                 cinterval = tsk->signal->it_prof_incr;
206                 if (!cputime_eq(cval, cputime_zero) ||
207                     !cputime_eq(nval, cputime_zero)) {
208                         if (cputime_gt(nval, cputime_zero))
209                                 nval = cputime_add(nval,
210                                                    jiffies_to_cputime(1));
211                         set_process_cpu_timer(tsk, CPUCLOCK_PROF,
212                                               &nval, &cval);
213                 }
214                 tsk->signal->it_prof_expires = nval;
215                 tsk->signal->it_prof_incr = ninterval;
216                 spin_unlock_irq(&tsk->sighand->siglock);
217                 read_unlock(&tasklist_lock);
218                 if (ovalue) {
219                         cputime_to_timeval(cval, &ovalue->it_value);
220                         cputime_to_timeval(cinterval, &ovalue->it_interval);
221                 }
222                 break;
223         default:
224                 return -EINVAL;
225         }
226         return 0;
227 }
228
229 asmlinkage long sys_setitimer(int which,
230                               struct itimerval __user *value,
231                               struct itimerval __user *ovalue)
232 {
233         struct itimerval set_buffer, get_buffer;
234         int error;
235
236         if (value) {
237                 if(copy_from_user(&set_buffer, value, sizeof(set_buffer)))
238                         return -EFAULT;
239         } else
240                 memset((char *) &set_buffer, 0, sizeof(set_buffer));
241
242         error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL);
243         if (error || !ovalue)
244                 return error;
245
246         if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer)))
247                 return -EFAULT; 
248         return 0;
249 }