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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>
1 jermar 57
 
1434 palkovsky 58
/* Pointers to public variables with time */
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struct ptime {
1780 jermar 60
	unative_t seconds1;
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	unative_t useconds;
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	unative_t seconds2;
1434 palkovsky 63
};
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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 68
static unative_t secfrag = 0;
1434 palkovsky 69
 
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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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 * 
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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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1760 palkovsky 82
	faddr = frame_alloc(0, FRAME_ATOMIC);
1434 palkovsky 83
	if (!faddr)
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		panic("Cannot allocate page for clock");
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	public_time = (struct ptime *)PA2KA(faddr);
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        /* TODO: We would need some arch dependent settings here */
1438 palkovsky 89
	public_time->seconds1 = 0;
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	public_time->seconds2 = 0;
1434 palkovsky 91
	public_time->useconds = 0; 
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1780 jermar 93
	sysinfo_set_item_val("clock.faddr", NULL, (unative_t)faddr);
1434 palkovsky 94
}
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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 107
			secfrag -= 1000000;
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			public_time->seconds1++;
1434 palkovsky 109
			write_barrier();
1438 palkovsky 110
			public_time->useconds = secfrag;
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			write_barrier();
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			public_time->seconds2 = public_time->seconds1;
1434 palkovsky 113
		} else
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			public_time->useconds += 1000000/HZ;
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	}
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}
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107 decky 118
/** Clock routine
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 *
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 * Clock routine executed from clock interrupt handler
413 jermar 121
 * (assuming interrupts_disable()'d). Runs expired timeouts
107 decky 122
 * and preemptive scheduling.
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 *
1 jermar 124
 */
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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 129
	timeout_handler_t f;
1 jermar 130
	void *arg;
1457 jermar 131
	count_t missed_clock_ticks = CPU->missed_clock_ticks;
1431 jermar 132
	int i;
1 jermar 133
 
134
	/*
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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 138
	for (i = 0; i <= missed_clock_ticks; i++) {
1434 palkovsky 139
		clock_update_counters();
1431 jermar 140
		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 158
		}
15 jermar 159
		spinlock_unlock(&CPU->timeoutlock);
1 jermar 160
	}
1431 jermar 161
	CPU->missed_clock_ticks = 0;
1 jermar 162
 
163
	/*
15 jermar 164
	 * Do CPU usage accounting and find out whether to preempt THREAD.
1 jermar 165
	 */
166
 
15 jermar 167
	if (THREAD) {
1780 jermar 168
		uint64_t ticks;
221 jermar 169
 
15 jermar 170
		spinlock_lock(&CPU->lock);
1457 jermar 171
		CPU->needs_relink += 1 + missed_clock_ticks;
15 jermar 172
		spinlock_unlock(&CPU->lock);	
1 jermar 173
 
15 jermar 174
		spinlock_lock(&THREAD->lock);
1457 jermar 175
		if ((ticks = THREAD->ticks)) {
176
			if (ticks >= 1 + missed_clock_ticks)
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				THREAD->ticks -= 1 + missed_clock_ticks;
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			else
179
				THREAD->ticks = 0;
180
		}
221 jermar 181
		spinlock_unlock(&THREAD->lock);
182
 
183
		if (!ticks && !PREEMPTION_DISABLED) {
1 jermar 184
			scheduler();
185
		}
186
	}
187
 
188
}
1702 cejka 189
 
1731 jermar 190
/** @}
1702 cejka 191
 */