scheduler.c

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/*
 * Copyright (C) 2006 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <proc/scheduler.h>
#include <proc/thread.h>
#include <arch.h>
#include <arch/register.h>
#include <arch/context.h>
#include <arch/stack.h>
#include <arch/mm/tlb.h>
#include <config.h>
#include <align.h>

void before_task_runs_arch(void)
{
}

void before_thread_runs_arch(void)
{
        __address base;
        
        base = ALIGN_DOWN(config.base, 1<<KERNEL_PAGE_WIDTH);

        if ((__address) THREAD->kstack < base || (__address) THREAD->kstack > base + (1<<(KERNEL_PAGE_WIDTH))) {
                /*
                 * Kernel stack of this thread is not mapped by DTR[TR_KERNEL].
                 * Use DTR[TR_KSTACK1] and DTR[TR_KSTACK2] to map it.
                 */
                 
                /* purge DTR[TR_STACK1] and DTR[TR_STACK2] */
                dtr_purge((__address) THREAD->kstack, PAGE_WIDTH+1);
                
                /* insert DTR[TR_STACK1] and DTR[TR_STACK2] */
                dtlb_kernel_mapping_insert((__address) THREAD->kstack, KA2PA(THREAD->kstack), true, DTR_KSTACK1);
                dtlb_kernel_mapping_insert((__address) THREAD->kstack + PAGE_SIZE, KA2PA(THREAD->kstack) + FRAME_SIZE, true, DTR_KSTACK2);
        }
        
        /*
         * Record address of kernel backing store to bank 0 r22.
         * Record address of kernel stack to bank 0 r23.
         * These values will be found there after switch from userspace.
         */
        __asm__ volatile (
                "bsw.0\n"
                "mov r22 = %0\n"
                "mov r23 = %1\n"
                "bsw.1\n"
                :
                : "r" (&THREAD->kstack[THREAD_STACK_SIZE]),
                  "r" (&THREAD->kstack[THREAD_STACK_SIZE - SP_DELTA])
                );
}

void after_thread_ran_arch(void)
{
}

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