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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> | |
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> | |
2ff678b8 | 15 | #include <linux/hrtimer.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 | { |
2ff678b8 | 29 | ktime_t rem = hrtimer_get_remaining(timer); |
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 | ||
45 | int do_getitimer(int which, struct itimerval *value) | |
46 | { | |
47 | struct task_struct *tsk = current; | |
1da177e4 LT |
48 | cputime_t cinterval, cval; |
49 | ||
50 | switch (which) { | |
51 | case ITIMER_REAL: | |
2ff678b8 TG |
52 | value->it_value = itimer_get_remtime(&tsk->signal->real_timer); |
53 | value->it_interval = | |
54 | ktime_to_timeval(tsk->signal->it_real_incr); | |
1da177e4 LT |
55 | break; |
56 | case ITIMER_VIRTUAL: | |
57 | read_lock(&tasklist_lock); | |
58 | spin_lock_irq(&tsk->sighand->siglock); | |
59 | cval = tsk->signal->it_virt_expires; | |
60 | cinterval = tsk->signal->it_virt_incr; | |
61 | if (!cputime_eq(cval, cputime_zero)) { | |
62 | struct task_struct *t = tsk; | |
63 | cputime_t utime = tsk->signal->utime; | |
64 | do { | |
65 | utime = cputime_add(utime, t->utime); | |
66 | t = next_thread(t); | |
67 | } while (t != tsk); | |
68 | if (cputime_le(cval, utime)) { /* about to fire */ | |
69 | cval = jiffies_to_cputime(1); | |
70 | } else { | |
71 | cval = cputime_sub(cval, utime); | |
72 | } | |
73 | } | |
74 | spin_unlock_irq(&tsk->sighand->siglock); | |
75 | read_unlock(&tasklist_lock); | |
76 | cputime_to_timeval(cval, &value->it_value); | |
77 | cputime_to_timeval(cinterval, &value->it_interval); | |
78 | break; | |
79 | case ITIMER_PROF: | |
80 | read_lock(&tasklist_lock); | |
81 | spin_lock_irq(&tsk->sighand->siglock); | |
82 | cval = tsk->signal->it_prof_expires; | |
83 | cinterval = tsk->signal->it_prof_incr; | |
84 | if (!cputime_eq(cval, cputime_zero)) { | |
85 | struct task_struct *t = tsk; | |
86 | cputime_t ptime = cputime_add(tsk->signal->utime, | |
87 | tsk->signal->stime); | |
88 | do { | |
89 | ptime = cputime_add(ptime, | |
90 | cputime_add(t->utime, | |
91 | t->stime)); | |
92 | t = next_thread(t); | |
93 | } while (t != tsk); | |
94 | if (cputime_le(cval, ptime)) { /* about to fire */ | |
95 | cval = jiffies_to_cputime(1); | |
96 | } else { | |
97 | cval = cputime_sub(cval, ptime); | |
98 | } | |
99 | } | |
100 | spin_unlock_irq(&tsk->sighand->siglock); | |
101 | read_unlock(&tasklist_lock); | |
102 | cputime_to_timeval(cval, &value->it_value); | |
103 | cputime_to_timeval(cinterval, &value->it_interval); | |
104 | break; | |
105 | default: | |
106 | return(-EINVAL); | |
107 | } | |
108 | return 0; | |
109 | } | |
110 | ||
111 | asmlinkage long sys_getitimer(int which, struct itimerval __user *value) | |
112 | { | |
113 | int error = -EFAULT; | |
114 | struct itimerval get_buffer; | |
115 | ||
116 | if (value) { | |
117 | error = do_getitimer(which, &get_buffer); | |
118 | if (!error && | |
119 | copy_to_user(value, &get_buffer, sizeof(get_buffer))) | |
120 | error = -EFAULT; | |
121 | } | |
122 | return error; | |
123 | } | |
124 | ||
1da177e4 | 125 | |
2ff678b8 TG |
126 | /* |
127 | * The timer is automagically restarted, when interval != 0 | |
128 | */ | |
129 | int it_real_fn(void *data) | |
1da177e4 | 130 | { |
2ff678b8 | 131 | struct task_struct *tsk = (struct task_struct *) data; |
1da177e4 | 132 | |
2ff678b8 | 133 | send_group_sig_info(SIGALRM, SEND_SIG_PRIV, tsk); |
1da177e4 | 134 | |
2ff678b8 TG |
135 | if (tsk->signal->it_real_incr.tv64 != 0) { |
136 | hrtimer_forward(&tsk->signal->real_timer, | |
137 | tsk->signal->it_real_incr); | |
138 | ||
139 | return HRTIMER_RESTART; | |
140 | } | |
141 | return HRTIMER_NORESTART; | |
1da177e4 LT |
142 | } |
143 | ||
144 | int do_setitimer(int which, struct itimerval *value, struct itimerval *ovalue) | |
145 | { | |
146 | struct task_struct *tsk = current; | |
2ff678b8 TG |
147 | struct hrtimer *timer; |
148 | ktime_t expires; | |
1da177e4 LT |
149 | cputime_t cval, cinterval, nval, ninterval; |
150 | ||
151 | switch (which) { | |
152 | case ITIMER_REAL: | |
2ff678b8 TG |
153 | timer = &tsk->signal->real_timer; |
154 | hrtimer_cancel(timer); | |
1da177e4 | 155 | if (ovalue) { |
2ff678b8 TG |
156 | ovalue->it_value = itimer_get_remtime(timer); |
157 | ovalue->it_interval | |
158 | = ktime_to_timeval(tsk->signal->it_real_incr); | |
1da177e4 | 159 | } |
2ff678b8 TG |
160 | tsk->signal->it_real_incr = |
161 | timeval_to_ktime(value->it_interval); | |
162 | expires = timeval_to_ktime(value->it_value); | |
163 | if (expires.tv64 != 0) | |
164 | hrtimer_start(timer, expires, HRTIMER_REL); | |
1da177e4 LT |
165 | break; |
166 | case ITIMER_VIRTUAL: | |
167 | nval = timeval_to_cputime(&value->it_value); | |
168 | ninterval = timeval_to_cputime(&value->it_interval); | |
169 | read_lock(&tasklist_lock); | |
170 | spin_lock_irq(&tsk->sighand->siglock); | |
171 | cval = tsk->signal->it_virt_expires; | |
172 | cinterval = tsk->signal->it_virt_incr; | |
173 | if (!cputime_eq(cval, cputime_zero) || | |
174 | !cputime_eq(nval, cputime_zero)) { | |
175 | if (cputime_gt(nval, cputime_zero)) | |
176 | nval = cputime_add(nval, | |
177 | jiffies_to_cputime(1)); | |
178 | set_process_cpu_timer(tsk, CPUCLOCK_VIRT, | |
179 | &nval, &cval); | |
180 | } | |
181 | tsk->signal->it_virt_expires = nval; | |
182 | tsk->signal->it_virt_incr = ninterval; | |
183 | spin_unlock_irq(&tsk->sighand->siglock); | |
184 | read_unlock(&tasklist_lock); | |
185 | if (ovalue) { | |
186 | cputime_to_timeval(cval, &ovalue->it_value); | |
187 | cputime_to_timeval(cinterval, &ovalue->it_interval); | |
188 | } | |
189 | break; | |
190 | case ITIMER_PROF: | |
191 | nval = timeval_to_cputime(&value->it_value); | |
192 | ninterval = timeval_to_cputime(&value->it_interval); | |
193 | read_lock(&tasklist_lock); | |
194 | spin_lock_irq(&tsk->sighand->siglock); | |
195 | cval = tsk->signal->it_prof_expires; | |
196 | cinterval = tsk->signal->it_prof_incr; | |
197 | if (!cputime_eq(cval, cputime_zero) || | |
198 | !cputime_eq(nval, cputime_zero)) { | |
199 | if (cputime_gt(nval, cputime_zero)) | |
200 | nval = cputime_add(nval, | |
201 | jiffies_to_cputime(1)); | |
202 | set_process_cpu_timer(tsk, CPUCLOCK_PROF, | |
203 | &nval, &cval); | |
204 | } | |
205 | tsk->signal->it_prof_expires = nval; | |
206 | tsk->signal->it_prof_incr = ninterval; | |
207 | spin_unlock_irq(&tsk->sighand->siglock); | |
208 | read_unlock(&tasklist_lock); | |
209 | if (ovalue) { | |
210 | cputime_to_timeval(cval, &ovalue->it_value); | |
211 | cputime_to_timeval(cinterval, &ovalue->it_interval); | |
212 | } | |
213 | break; | |
214 | default: | |
215 | return -EINVAL; | |
216 | } | |
217 | return 0; | |
218 | } | |
219 | ||
220 | asmlinkage long sys_setitimer(int which, | |
221 | struct itimerval __user *value, | |
222 | struct itimerval __user *ovalue) | |
223 | { | |
224 | struct itimerval set_buffer, get_buffer; | |
225 | int error; | |
226 | ||
227 | if (value) { | |
228 | if(copy_from_user(&set_buffer, value, sizeof(set_buffer))) | |
229 | return -EFAULT; | |
230 | } else | |
231 | memset((char *) &set_buffer, 0, sizeof(set_buffer)); | |
232 | ||
233 | error = do_setitimer(which, &set_buffer, ovalue ? &get_buffer : NULL); | |
234 | if (error || !ovalue) | |
235 | return error; | |
236 | ||
237 | if (copy_to_user(ovalue, &get_buffer, sizeof(get_buffer))) | |
238 | return -EFAULT; | |
239 | return 0; | |
240 | } |