xref: /linux/arch/um/os-Linux/time.c (revision 6e8331ac6973435b1e7604c30f2ad394035b46e1)
1 /*
2  * Copyright (C) 2000, 2001, 2002 Jeff Dike (jdike@karaya.com)
3  * Licensed under the GPL
4  */
5 
6 #include <stdio.h>
7 #include <stdlib.h>
8 #include <unistd.h>
9 #include <time.h>
10 #include <sys/time.h>
11 #include <signal.h>
12 #include <errno.h>
13 #include "user_util.h"
14 #include "kern_util.h"
15 #include "user.h"
16 #include "process.h"
17 #include "kern_constants.h"
18 #include "os.h"
19 
20 static void set_interval(int timer_type)
21 {
22 	int usec = 1000000/hz();
23 	struct itimerval interval = ((struct itimerval) { { 0, usec },
24 							  { 0, usec } });
25 
26 	if(setitimer(timer_type, &interval, NULL) == -1)
27 		panic("setitimer failed - errno = %d\n", errno);
28 }
29 
30 void enable_timer(void)
31 {
32 	set_interval(ITIMER_VIRTUAL);
33 }
34 
35 void disable_timer(void)
36 {
37 	struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
38 	if((setitimer(ITIMER_VIRTUAL, &disable, NULL) < 0) ||
39 	   (setitimer(ITIMER_REAL, &disable, NULL) < 0))
40 		printk("disnable_timer - setitimer failed, errno = %d\n",
41 		       errno);
42 	/* If there are signals already queued, after unblocking ignore them */
43 	set_handler(SIGALRM, SIG_IGN, 0, -1);
44 	set_handler(SIGVTALRM, SIG_IGN, 0, -1);
45 }
46 
47 void switch_timers(int to_real)
48 {
49 	struct itimerval disable = ((struct itimerval) { { 0, 0 }, { 0, 0 }});
50 	struct itimerval enable = ((struct itimerval) { { 0, 1000000/hz() },
51 							{ 0, 1000000/hz() }});
52 	int old, new;
53 
54 	if(to_real){
55 		old = ITIMER_VIRTUAL;
56 		new = ITIMER_REAL;
57 	}
58 	else {
59 		old = ITIMER_REAL;
60 		new = ITIMER_VIRTUAL;
61 	}
62 
63 	if((setitimer(old, &disable, NULL) < 0) ||
64 	   (setitimer(new, &enable, NULL)))
65 		printk("switch_timers - setitimer failed, errno = %d\n",
66 		       errno);
67 }
68 
69 #ifdef UML_CONFIG_MODE_TT
70 void uml_idle_timer(void)
71 {
72 	if(signal(SIGVTALRM, SIG_IGN) == SIG_ERR)
73 		panic("Couldn't unset SIGVTALRM handler");
74 
75 	set_handler(SIGALRM, (__sighandler_t) alarm_handler,
76 		    SA_RESTART, SIGUSR1, SIGIO, SIGWINCH, SIGVTALRM, -1);
77 	set_interval(ITIMER_REAL);
78 }
79 #endif
80 
81 unsigned long long os_nsecs(void)
82 {
83 	struct timeval tv;
84 
85 	gettimeofday(&tv, NULL);
86 	return((unsigned long long) tv.tv_sec * BILLION + tv.tv_usec * 1000);
87 }
88 
89 void idle_sleep(int secs)
90 {
91 	struct timespec ts;
92 
93 	ts.tv_sec = secs;
94 	ts.tv_nsec = 0;
95 	nanosleep(&ts, NULL);
96 }
97 
98 void user_time_init(void)
99 {
100 	set_interval(ITIMER_VIRTUAL);
101 }
102