aboutsummaryrefslogtreecommitdiff
path: root/arch/um/kernel/time_kern.c
blob: 6516fc52afe01f23ecfbe0365cb251e9d3c8635d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
/* 
 * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
 * Licensed under the GPL
 */

#include "linux/kernel.h"
#include "linux/module.h"
#include "linux/unistd.h"
#include "linux/stddef.h"
#include "linux/spinlock.h"
#include "linux/time.h"
#include "linux/sched.h"
#include "linux/interrupt.h"
#include "linux/init.h"
#include "linux/delay.h"
#include "asm/irq.h"
#include "asm/param.h"
#include "asm/current.h"
#include "kern_util.h"
#include "user_util.h"
#include "time_user.h"
#include "mode.h"
#include "os.h"

u64 jiffies_64 = INITIAL_JIFFIES;

EXPORT_SYMBOL(jiffies_64);

int hz(void)
{
	return(HZ);
}

/*
 * Scheduler clock - returns current time in nanosec units.
 */
unsigned long long sched_clock(void)
{
	return (unsigned long long)jiffies_64 * (1000000000 / HZ);
}

/* Changed at early boot */
int timer_irq_inited = 0;

static int first_tick;
static unsigned long long prev_usecs;
#ifdef CONFIG_UML_REAL_TIME_CLOCK
static long long delta;   		/* Deviation per interval */
#endif

void timer_irq(union uml_pt_regs *regs)
{
	unsigned long long ticks = 0;

	if(!timer_irq_inited){
		/* This is to ensure that ticks don't pile up when
		 * the timer handler is suspended */
		first_tick = 0;
		return;
	}

	if(first_tick){
#ifdef CONFIG_UML_REAL_TIME_CLOCK
		/* We've had 1 tick */
		unsigned long long usecs = os_usecs();

		delta += usecs - prev_usecs;
		prev_usecs = usecs;

		/* Protect against the host clock being set backwards */
		if(delta < 0)
			delta = 0;

		ticks += (delta * HZ) / MILLION;
		delta -= (ticks * MILLION) / HZ;
#else
		ticks = 1;
#endif
	}
	else {
		prev_usecs = os_usecs();
		first_tick = 1;
	}

	while(ticks > 0){
		do_IRQ(TIMER_IRQ, regs);
		ticks--;
	}
}

void boot_timer_handler(int sig)
{
	struct pt_regs regs;

	CHOOSE_MODE((void) 
		    (UPT_SC(&regs.regs) = (struct sigcontext *) (&sig + 1)),
		    (void) (regs.regs.skas.is_user = 0));
	do_timer(&regs);
}

irqreturn_t um_timer(int irq, void *dev, struct pt_regs *regs)
{
	unsigned long flags;

	do_timer(regs);
	write_seqlock_irqsave(&xtime_lock, flags);
	timer();
	write_sequnlock_irqrestore(&xtime_lock, flags);
	return(IRQ_HANDLED);
}

long um_time(int __user *tloc)
{
	struct timeval now;

	do_gettimeofday(&now);
	if (tloc) {
 		if (put_user(now.tv_sec, tloc))
			now.tv_sec = -EFAULT;
	}
	return now.tv_sec;
}

long um_stime(int __user *tptr)
{
	int value;
	struct timespec new;

	if (get_user(value, tptr))
                return -EFAULT;
	new.tv_sec = value;
	new.tv_nsec = 0;
	do_settimeofday(&new);
	return 0;
}

void timer_handler(int sig, union uml_pt_regs *regs)
{
	local_irq_disable();
	update_process_times(CHOOSE_MODE(user_context(UPT_SP(regs)), (regs)->skas.is_user));
	local_irq_enable();
	if(current_thread->cpu == 0)
		timer_irq(regs);
}

static DEFINE_SPINLOCK(timer_spinlock);

unsigned long time_lock(void)
{
	unsigned long flags;

	spin_lock_irqsave(&timer_spinlock, flags);
	return(flags);
}

void time_unlock(unsigned long flags)
{
	spin_unlock_irqrestore(&timer_spinlock, flags);
}

int __init timer_init(void)
{
	int err;

	CHOOSE_MODE(user_time_init_tt(), user_time_init_skas());
	err = request_irq(TIMER_IRQ, um_timer, SA_INTERRUPT, "timer", NULL);
	if(err != 0)
		printk(KERN_ERR "timer_init : request_irq failed - "
		       "errno = %d\n", -err);
	timer_irq_inited = 1;
	return(0);
}

__initcall(timer_init);

/*
 * Overrides for Emacs so that we follow Linus's tabbing style.
 * Emacs will notice this stuff at the end of the file and automatically
 * adjust the settings for this buffer only.  This must remain at the end
 * of the file.
 * ---------------------------------------------------------------------------
 * Local variables:
 * c-file-style: "linux"
 * End:
 */