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1 jermar 1
/*
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 * Copyright (C) 2001-2004 Jakub Jermar
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 *
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 * - Redistributions of source code must retain the above copyright
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 *   notice, this list of conditions and the following disclaimer.
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 * - Redistributions in binary form must reproduce the above copyright
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 *   notice, this list of conditions and the following disclaimer in the
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 *   documentation and/or other materials provided with the distribution.
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 * - The name of the author may not be used to endorse or promote products
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 *   derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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 */
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1731 jermar 29
/** @addtogroup time
1702 cejka 30
 * @{
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 */
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1264 jermar 33
/**
1702 cejka 34
 * @file
1264 jermar 35
 * @brief   High-level clock interrupt handler.
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 *
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 * This file contains the clock() function which is the source
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 * of preemption. It is also responsible for executing expired
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 * timeouts.
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 */
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1 jermar 42
#include <time/clock.h>
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#include <time/timeout.h>
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#include <arch/types.h>
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#include <config.h>
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#include <synch/spinlock.h>
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#include <synch/waitq.h>
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#include <func.h>
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#include <proc/scheduler.h>
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#include <cpu.h>
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#include <arch.h>
788 jermar 52
#include <adt/list.h>
1104 jermar 53
#include <atomic.h>
391 jermar 54
#include <proc/thread.h>
1434 palkovsky 55
#include <sysinfo/sysinfo.h>
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#include <arch/barrier.h>
2015 jermar 57
#include <mm/frame.h>
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#include <ddi/ddi.h>
1 jermar 59
 
2015 jermar 60
/** Physical memory area of the real time clock. */
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static parea_t clock_parea;
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1434 palkovsky 63
/* Pointers to public variables with time */
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struct ptime {
1780 jermar 65
    unative_t seconds1;
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    unative_t useconds;
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    unative_t seconds2;
1434 palkovsky 68
};
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struct ptime *public_time;
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/* Variable holding fragment of second, so that we would update
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 * seconds correctly
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 */
1780 jermar 73
static unative_t secfrag = 0;
1434 palkovsky 74
 
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/** Initialize realtime clock counter
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 *
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 * The applications (and sometimes kernel) need to access accurate
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 * information about realtime data. We allocate 1 page with these
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 * data and update it periodically.
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 */
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void clock_counter_init(void)
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{
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    void *faddr;
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2015 jermar 85
    faddr = frame_alloc(ONE_FRAME, FRAME_ATOMIC);
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    if (!faddr)
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        panic("Cannot allocate page for clock");
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2015 jermar 89
    public_time = (struct ptime *) PA2KA(faddr);
1434 palkovsky 90
 
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        /* TODO: We would need some arch dependent settings here */
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    public_time->seconds1 = 0;
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    public_time->seconds2 = 0;
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    public_time->useconds = 0;
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2015 jermar 96
    clock_parea.pbase = (uintptr_t) faddr;
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    clock_parea.vbase = (uintptr_t) public_time;
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    clock_parea.frames = 1;
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    clock_parea.cacheable = true;
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    ddi_parea_register(&clock_parea);
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    /*
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     * Prepare information for the userspace so that it can successfully
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     * physmem_map() the clock_parea.
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     */
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    sysinfo_set_item_val("clock.cacheable", NULL, (unative_t) true);
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    sysinfo_set_item_val("clock.fcolor", NULL, (unative_t)
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        PAGE_COLOR(clock_parea.vbase));
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    sysinfo_set_item_val("clock.faddr", NULL, (unative_t) faddr);
1434 palkovsky 110
}
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/** Update public counters
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 *
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 * Update it only on first processor
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 * TODO: Do we really need so many write barriers?
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 */
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static void clock_update_counters(void)
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{
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    if (CPU->id == 0) {
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        secfrag += 1000000/HZ;
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        if (secfrag >= 1000000) {
1438 palkovsky 123
            secfrag -= 1000000;
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            public_time->seconds1++;
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            write_barrier();
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            public_time->useconds = secfrag;
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            write_barrier();
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            public_time->seconds2 = public_time->seconds1;
1434 palkovsky 129
        } else
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            public_time->useconds += 1000000/HZ;
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    }
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}
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107 decky 134
/** Clock routine
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 *
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 * Clock routine executed from clock interrupt handler
413 jermar 137
 * (assuming interrupts_disable()'d). Runs expired timeouts
107 decky 138
 * and preemptive scheduling.
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 *
1 jermar 140
 */
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void clock(void)
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{
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    link_t *l;
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    timeout_t *h;
411 jermar 145
    timeout_handler_t f;
1 jermar 146
    void *arg;
1457 jermar 147
    count_t missed_clock_ticks = CPU->missed_clock_ticks;
1431 jermar 148
    int i;
1 jermar 149
 
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    /*
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     * To avoid lock ordering problems,
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     * run all expired timeouts as you visit them.
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     */
1457 jermar 154
    for (i = 0; i <= missed_clock_ticks; i++) {
1434 palkovsky 155
        clock_update_counters();
1431 jermar 156
        spinlock_lock(&CPU->timeoutlock);
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        while ((l = CPU->timeout_active_head.next) != &CPU->timeout_active_head) {
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            h = list_get_instance(l, timeout_t, link);
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            spinlock_lock(&h->lock);
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            if (h->ticks-- != 0) {
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                spinlock_unlock(&h->lock);
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                break;
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            }
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            list_remove(l);
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            f = h->handler;
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            arg = h->arg;
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            timeout_reinitialize(h);
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            spinlock_unlock(&h->lock); 
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            spinlock_unlock(&CPU->timeoutlock);
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            f(arg);
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            spinlock_lock(&CPU->timeoutlock);
1 jermar 174
        }
15 jermar 175
        spinlock_unlock(&CPU->timeoutlock);
1 jermar 176
    }
1431 jermar 177
    CPU->missed_clock_ticks = 0;
1 jermar 178
 
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    /*
15 jermar 180
     * Do CPU usage accounting and find out whether to preempt THREAD.
1 jermar 181
     */
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15 jermar 183
    if (THREAD) {
1780 jermar 184
        uint64_t ticks;
221 jermar 185
 
15 jermar 186
        spinlock_lock(&CPU->lock);
1457 jermar 187
        CPU->needs_relink += 1 + missed_clock_ticks;
15 jermar 188
        spinlock_unlock(&CPU->lock);   
1 jermar 189
 
15 jermar 190
        spinlock_lock(&THREAD->lock);
1457 jermar 191
        if ((ticks = THREAD->ticks)) {
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            if (ticks >= 1 + missed_clock_ticks)
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                THREAD->ticks -= 1 + missed_clock_ticks;
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            else
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                THREAD->ticks = 0;
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        }
221 jermar 197
        spinlock_unlock(&THREAD->lock);
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        if (!ticks && !PREEMPTION_DISABLED) {
1 jermar 200
            scheduler();
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        }
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    }
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}
1702 cejka 205
 
1731 jermar 206
/** @}
1702 cejka 207
 */