xref: /openbmc/linux/kernel/time/posix-stubs.c (revision e4781421e883340b796da5a724bda7226817990b)
1 /*
2  * Dummy stubs used when CONFIG_POSIX_TIMERS=n
3  *
4  * Created by:  Nicolas Pitre, July 2016
5  * Copyright:   (C) 2016 Linaro Limited
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License version 2 as
9  * published by the Free Software Foundation.
10  */
11 
12 #include <linux/linkage.h>
13 #include <linux/kernel.h>
14 #include <linux/sched.h>
15 #include <linux/errno.h>
16 #include <linux/syscalls.h>
17 #include <linux/ktime.h>
18 #include <linux/timekeeping.h>
19 #include <linux/posix-timers.h>
20 
21 asmlinkage long sys_ni_posix_timers(void)
22 {
23 	pr_err_once("process %d (%s) attempted a POSIX timer syscall "
24 		    "while CONFIG_POSIX_TIMERS is not set\n",
25 		    current->pid, current->comm);
26 	return -ENOSYS;
27 }
28 
29 #define SYS_NI(name)  SYSCALL_ALIAS(sys_##name, sys_ni_posix_timers)
30 
31 SYS_NI(timer_create);
32 SYS_NI(timer_gettime);
33 SYS_NI(timer_getoverrun);
34 SYS_NI(timer_settime);
35 SYS_NI(timer_delete);
36 SYS_NI(clock_adjtime);
37 SYS_NI(getitimer);
38 SYS_NI(setitimer);
39 #ifdef __ARCH_WANT_SYS_ALARM
40 SYS_NI(alarm);
41 #endif
42 
43 /*
44  * We preserve minimal support for CLOCK_REALTIME and CLOCK_MONOTONIC
45  * as it is easy to remain compatible with little code. CLOCK_BOOTTIME
46  * is also included for convenience as at least systemd uses it.
47  */
48 
49 SYSCALL_DEFINE2(clock_settime, const clockid_t, which_clock,
50 		const struct timespec __user *, tp)
51 {
52 	struct timespec new_tp;
53 
54 	if (which_clock != CLOCK_REALTIME)
55 		return -EINVAL;
56 	if (copy_from_user(&new_tp, tp, sizeof (*tp)))
57 		return -EFAULT;
58 	return do_sys_settimeofday(&new_tp, NULL);
59 }
60 
61 SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock,
62 		struct timespec __user *,tp)
63 {
64 	struct timespec kernel_tp;
65 
66 	switch (which_clock) {
67 	case CLOCK_REALTIME: ktime_get_real_ts(&kernel_tp); break;
68 	case CLOCK_MONOTONIC: ktime_get_ts(&kernel_tp); break;
69 	case CLOCK_BOOTTIME: get_monotonic_boottime(&kernel_tp); break;
70 	default: return -EINVAL;
71 	}
72 	if (copy_to_user(tp, &kernel_tp, sizeof (kernel_tp)))
73 		return -EFAULT;
74 	return 0;
75 }
76 
77 SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp)
78 {
79 	struct timespec rtn_tp = {
80 		.tv_sec = 0,
81 		.tv_nsec = hrtimer_resolution,
82 	};
83 
84 	switch (which_clock) {
85 	case CLOCK_REALTIME:
86 	case CLOCK_MONOTONIC:
87 	case CLOCK_BOOTTIME:
88 		if (copy_to_user(tp, &rtn_tp, sizeof(rtn_tp)))
89 			return -EFAULT;
90 		return 0;
91 	default:
92 		return -EINVAL;
93 	}
94 }
95 
96 SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
97 		const struct timespec __user *, rqtp,
98 		struct timespec __user *, rmtp)
99 {
100 	struct timespec t;
101 
102 	switch (which_clock) {
103 	case CLOCK_REALTIME:
104 	case CLOCK_MONOTONIC:
105 	case CLOCK_BOOTTIME:
106 		if (copy_from_user(&t, rqtp, sizeof (struct timespec)))
107 			return -EFAULT;
108 		if (!timespec_valid(&t))
109 			return -EINVAL;
110 		return hrtimer_nanosleep(&t, rmtp, flags & TIMER_ABSTIME ?
111 					 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
112 					 which_clock);
113 	default:
114 		return -EINVAL;
115 	}
116 }
117 
118 #ifdef CONFIG_COMPAT
119 long clock_nanosleep_restart(struct restart_block *restart_block)
120 {
121 	return hrtimer_nanosleep_restart(restart_block);
122 }
123 #endif
124