source: mainline/genarch/src/mm/as_pt.c@ 37c57f2

/*
 * 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 <genarch/mm/page_pt.h>
#include <mm/page.h>
#include <mm/frame.h>
#include <mm/as.h>
#include <arch/mm/page.h>
#include <arch/mm/as.h>
#include <arch/types.h>
#include <typedefs.h>
#include <memstr.h>
#include <arch.h>

static pte_t *ptl0_create(int flags);

static void pt_lock(as_t *as, bool lock);
static void pt_unlock(as_t *as, bool unlock);

as_operations_t as_pt_operations = {
        .page_table_create = ptl0_create,
        .page_table_lock = pt_lock,
        .page_table_unlock = pt_unlock
};

/** Create PTL0.
 *
 * PTL0 of 4-level page table will be created for each address space.
 *
 * @param flags Flags can specify whether ptl0 is for the kernel address space.
 *
 * @return New PTL0.
 */
pte_t *ptl0_create(int flags)
{
        pte_t *src_ptl0, *dst_ptl0;
        ipl_t ipl;

        dst_ptl0 = (pte_t *) PA2KA(PFN2ADDR(frame_alloc(ONE_FRAME, FRAME_KA | FRAME_PANIC)));

        if (flags & FLAG_AS_KERNEL) {
                memsetb((__address) dst_ptl0, PAGE_SIZE, 0);
        } else {
                __address src, dst;
        
                /*
                 * Copy the kernel address space portion to new PTL0.
                 */
                 
                ipl = interrupts_disable();
                spinlock_lock(&AS_KERNEL->lock);                
                src_ptl0 = (pte_t *) PA2KA((__address) AS_KERNEL->page_table);

                src = (__address) &src_ptl0[PTL0_INDEX(KERNEL_ADDRESS_SPACE_START)];
                dst = (__address) &dst_ptl0[PTL0_INDEX(KERNEL_ADDRESS_SPACE_START)];

                memsetb((__address) dst_ptl0, PAGE_SIZE, 0);
                memcpy((void *) dst, (void *) src, PAGE_SIZE - (src - (__address) src_ptl0));
                spinlock_unlock(&AS_KERNEL->lock);
                interrupts_restore(ipl);
        }

        return (pte_t *) KA2PA((__address) dst_ptl0);
}

/** Lock page tables.
 *
 * Lock only the address space.
 * Interrupts must be disabled.
 *
 * @param as Address space.
 * @param lock If false, do not attempt to lock the address space.
 */
void pt_lock(as_t *as, bool lock)
{
        if (lock)
                spinlock_lock(&as->lock);
}

/** Unlock page tables.
 *
 * Unlock the address space.
 * Interrupts must be disabled.
 *
 * @param as Address space.
 * @param unlock If false, do not attempt to unlock the address space.
 */
void pt_unlock(as_t *as, bool unlock)
{
        if (unlock)
                spinlock_unlock(&as->lock);
}