Subversion Repositories HelenOS

Rev

Rev 4339 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
1 jermar 1
/*
2071 jermar 2
 * Copyright (c) 2001-2004 Jakub Jermar
1 jermar 3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
13
 *   documentation and/or other materials provided with the distribution.
14
 * - The name of the author may not be used to endorse or promote products
15
 *   derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
1731 jermar 29
/** @addtogroup time
1702 cejka 30
 * @{
31
 */
32
 
1264 jermar 33
/**
1702 cejka 34
 * @file
1264 jermar 35
 * @brief   High-level clock interrupt handler.
36
 *
37
 * This file contains the clock() function which is the source
38
 * of preemption. It is also responsible for executing expired
39
 * timeouts.
40
 */
41
 
1 jermar 42
#include <time/clock.h>
43
#include <time/timeout.h>
44
#include <config.h>
45
#include <synch/spinlock.h>
46
#include <synch/waitq.h>
47
#include <func.h>
48
#include <proc/scheduler.h>
49
#include <cpu.h>
50
#include <arch.h>
788 jermar 51
#include <adt/list.h>
1104 jermar 52
#include <atomic.h>
391 jermar 53
#include <proc/thread.h>
1434 palkovsky 54
#include <sysinfo/sysinfo.h>
55
#include <arch/barrier.h>
2015 jermar 56
#include <mm/frame.h>
57
#include <ddi/ddi.h>
1 jermar 58
 
2275 decky 59
/* Pointer to variable with uptime */
60
uptime_t *uptime;
61
 
62
/** Physical memory area of the real time clock */
2015 jermar 63
static parea_t clock_parea;
64
 
1434 palkovsky 65
/* Variable holding fragment of second, so that we would update
66
 * seconds correctly
67
 */
1780 jermar 68
static unative_t secfrag = 0;
1434 palkovsky 69
 
70
/** Initialize realtime clock counter
71
 *
72
 * The applications (and sometimes kernel) need to access accurate
73
 * information about realtime data. We allocate 1 page with these
74
 * data and update it periodically.
75
 */
76
void clock_counter_init(void)
77
{
78
    void *faddr;
79
 
2015 jermar 80
    faddr = frame_alloc(ONE_FRAME, FRAME_ATOMIC);
1434 palkovsky 81
    if (!faddr)
4339 svoboda 82
        panic("Cannot allocate page for clock.");
1434 palkovsky 83
 
2275 decky 84
    uptime = (uptime_t *) PA2KA(faddr);
85
 
86
    uptime->seconds1 = 0;
87
    uptime->seconds2 = 0;
88
    uptime->useconds = 0;
1434 palkovsky 89
 
2015 jermar 90
    clock_parea.pbase = (uintptr_t) faddr;
91
    clock_parea.frames = 1;
92
    ddi_parea_register(&clock_parea);
93
 
94
    /*
95
     * Prepare information for the userspace so that it can successfully
96
     * physmem_map() the clock_parea.
97
     */
98
    sysinfo_set_item_val("clock.cacheable", NULL, (unative_t) true);
99
    sysinfo_set_item_val("clock.faddr", NULL, (unative_t) faddr);
1434 palkovsky 100
}
101
 
102
 
103
/** Update public counters
104
 *
105
 * Update it only on first processor
106
 * TODO: Do we really need so many write barriers?
107
 */
108
static void clock_update_counters(void)
109
{
110
    if (CPU->id == 0) {
2275 decky 111
        secfrag += 1000000 / HZ;
1434 palkovsky 112
        if (secfrag >= 1000000) {
1438 palkovsky 113
            secfrag -= 1000000;
2275 decky 114
            uptime->seconds1++;
1434 palkovsky 115
            write_barrier();
2275 decky 116
            uptime->useconds = secfrag;
1438 palkovsky 117
            write_barrier();
2275 decky 118
            uptime->seconds2 = uptime->seconds1;
1434 palkovsky 119
        } else
2275 decky 120
            uptime->useconds += 1000000 / HZ;
1434 palkovsky 121
    }
122
}
123
 
107 decky 124
/** Clock routine
125
 *
126
 * Clock routine executed from clock interrupt handler
413 jermar 127
 * (assuming interrupts_disable()'d). Runs expired timeouts
107 decky 128
 * and preemptive scheduling.
129
 *
1 jermar 130
 */
131
void clock(void)
132
{
133
    link_t *l;
134
    timeout_t *h;
411 jermar 135
    timeout_handler_t f;
1 jermar 136
    void *arg;
1457 jermar 137
    count_t missed_clock_ticks = CPU->missed_clock_ticks;
2745 decky 138
    unsigned int i;
1 jermar 139
 
140
    /*
141
     * To avoid lock ordering problems,
142
     * run all expired timeouts as you visit them.
143
     */
1457 jermar 144
    for (i = 0; i <= missed_clock_ticks; i++) {
1434 palkovsky 145
        clock_update_counters();
1431 jermar 146
        spinlock_lock(&CPU->timeoutlock);
147
        while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) {
148
            h = list_get_instance(l, timeout_t, link);
149
            spinlock_lock(&h->lock);
150
            if (h->ticks-- != 0) {
151
                spinlock_unlock(&h->lock);
152
                break;
153
            }
154
            list_remove(l);
155
            f = h->handler;
156
            arg = h->arg;
157
            timeout_reinitialize(h);
158
            spinlock_unlock(&h->lock); 
159
            spinlock_unlock(&CPU->timeoutlock);
160
 
161
            f(arg);
162
 
163
            spinlock_lock(&CPU->timeoutlock);
1 jermar 164
        }
15 jermar 165
        spinlock_unlock(&CPU->timeoutlock);
1 jermar 166
    }
1431 jermar 167
    CPU->missed_clock_ticks = 0;
1 jermar 168
 
169
    /*
15 jermar 170
     * Do CPU usage accounting and find out whether to preempt THREAD.
1 jermar 171
     */
172
 
15 jermar 173
    if (THREAD) {
1780 jermar 174
        uint64_t ticks;
221 jermar 175
 
15 jermar 176
        spinlock_lock(&CPU->lock);
1457 jermar 177
        CPU->needs_relink += 1 + missed_clock_ticks;
15 jermar 178
        spinlock_unlock(&CPU->lock);   
1 jermar 179
 
15 jermar 180
        spinlock_lock(&THREAD->lock);
1457 jermar 181
        if ((ticks = THREAD->ticks)) {
182
            if (ticks >= 1 + missed_clock_ticks)
183
                THREAD->ticks -= 1 + missed_clock_ticks;
184
            else
185
                THREAD->ticks = 0;
186
        }
221 jermar 187
        spinlock_unlock(&THREAD->lock);
188
 
189
        if (!ticks && !PREEMPTION_DISABLED) {
3694 svoboda 190
#ifdef CONFIG_UDEBUG
191
            istate_t *istate;
192
#endif
1 jermar 193
            scheduler();
3674 svoboda 194
#ifdef CONFIG_UDEBUG
195
            /*
196
             * Give udebug chance to stop the thread
3694 svoboda 197
             * before it begins executing userspace code.
3674 svoboda 198
             */
3694 svoboda 199
            istate = THREAD->udebug.uspace_state;
200
            if (istate && istate_from_uspace(istate))
3674 svoboda 201
                udebug_before_thread_runs();
202
#endif
1 jermar 203
        }
204
    }
205
 
206
}
1702 cejka 207
 
1731 jermar 208
/** @}
1702 cejka 209
 */