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/*

 * Copyright (C) 2001-2006 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.

 */

/*

 * This file contains address space manipulation functions.

 * Roughly speaking, this is a higher-level client of

 * Virtual Address Translation (VAT) subsystem.

 */

#include <mm/as.h>

#include <mm/page.h>

#include <mm/frame.h>

#include <mm/tlb.h>

#include <mm/heap.h>

#include <arch/mm/page.h>

#include <genarch/mm/page_pt.h>

#include <arch/mm/asid.h>

#include <arch/mm/as.h>

#include <arch/types.h>

#include <typedefs.h>

#include <synch/spinlock.h>

#include <config.h>

#include <list.h>

#include <panic.h>

#include <arch/asm.h>

#include <debug.h>

#include <memstr.h>

#include <arch.h>

#include <print.h>

#define KAS_START_INDEX     PTL0_INDEX(KERNEL_ADDRESS_SPACE_START)

#define KAS_END_INDEX       PTL0_INDEX(KERNEL_ADDRESS_SPACE_END)

#define KAS_INDICES     (1+(KAS_END_INDEX-KAS_START_INDEX))

/*

 * Here we assume that PFN (Physical Frame Number) space

 * is smaller than the width of index_t. UNALLOCATED_PFN

 * can be then used to mark mappings wich were not

 * yet allocated a physical frame.

 */

#define UNALLOCATED_PFN     ((index_t) -1)

/** Create address space. */

/*

 * FIXME: this interface must be meaningful for all possible VAT

 *    (Virtual Address Translation) mechanisms.

 */

as_t *as_create(pte_t *ptl0)

{

    as_t *as;

    as = (as_t *) malloc(sizeof(as_t));

    if (as) {

        spinlock_initialize(&as->lock, "as_lock");

        list_initialize(&as->as_area_head);

        as->asid = asid_get();

        as->ptl0 = ptl0;

        if (!as->ptl0) {

            pte_t *src_ptl0, *dst_ptl0;

            src_ptl0 = (pte_t *) PA2KA((__address) GET_PTL0_ADDRESS());

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

//          memsetb((__address) dst_ptl0, PAGE_SIZE, 0);

//          memcpy((void *) &dst_ptl0[KAS_START_INDEX], (void *) &src_ptl0[KAS_START_INDEX], KAS_INDICES);

            memcpy((void *) dst_ptl0,(void *) src_ptl0, PAGE_SIZE);

            as->ptl0 = (pte_t *) KA2PA((__address) dst_ptl0);

        }

    }

    return as;

}

/** Create address space area of common attributes.

 *

 * The created address space area is added to the target address space.

 *

 * @param as Target address space.

 * @param type Type of area.

 * @param size Size of area in multiples of PAGE_SIZE.

 * @param base Base address of area.

 *

 * @return Address space area on success or NULL on failure.

 */

as_area_t *as_area_create(as_t *as, as_area_type_t type, size_t size, __address base)

{

    ipl_t ipl;

    as_area_t *a;

    if (base % PAGE_SIZE)

        panic("addr not aligned to a page boundary");

    ipl = interrupts_disable();

    spinlock_lock(&as->lock);

    /*

     * TODO: test as_area which is to be created doesn't overlap with an existing one.

     */

    a = (as_area_t *) malloc(sizeof(as_area_t));

    if (a) {

        int i;

        a->mapping = (index_t *) malloc(size * sizeof(index_t));

        if (!a->mapping) {

            free(a);

            spinlock_unlock(&as->lock);

            interrupts_restore(ipl);

            return NULL;

        }

        for (i=0; i<size; i++) {

            /*

             * Frames will be allocated on-demand by

             * as_page_fault() or preloaded by

             * as_area_set_mapping().

             */

            a->mapping[i] = UNALLOCATED_PFN;

        }

        spinlock_initialize(&a->lock, "as_area_lock");

        link_initialize(&a->link);         

        a->type = type;

        a->size = size;

        a->base = base;

        list_append(&a->link, &as->as_area_head);

    }

    spinlock_unlock(&as->lock);

    interrupts_restore(ipl);

    return a;

}

/** Load mapping for address space area.

 *

 * Initialize a->mapping.

 *

 * @param a   Target address space area.

 * @param vpn Page number relative to area start.

 * @param pfn Frame number to map.

 */

void as_area_set_mapping(as_area_t *a, index_t vpn, index_t pfn)

{

    ASSERT(vpn < a->size);

    ASSERT(a->mapping[vpn] == UNALLOCATED_PFN);

    ASSERT(pfn != UNALLOCATED_PFN);

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&a->lock);

    a->mapping[vpn] = pfn;

    spinlock_unlock(&a->lock);

    interrupts_restore(ipl);

}

/** Handle page fault within the current address space.

 *

 * This is the high-level page fault handler.

 * Interrupts are assumed disabled.

 *

 * @param page Faulting page.

 *

 * @return 0 on page fault, 1 on success.

 */

int as_page_fault(__address page)

{

    int flags;

    link_t *cur;

    as_area_t *a, *area = NULL;

    index_t vpn;

    __address frame;

    ASSERT(AS);

    spinlock_lock(&AS->lock);

    /*

     * Search this areas of this address space for presence of 'page'.

     */

    for (cur = AS->as_area_head.next; cur != &AS->as_area_head; cur = cur->next) {

        a = list_get_instance(cur, as_area_t, link);

        spinlock_lock(&a->lock);

        if ((page >= a->base) && (page < a->base + a->size * PAGE_SIZE)) {

            /*

             * We found the area containing 'page'.

             * TODO: access checking

             */

            vpn = (page - a->base) / PAGE_SIZE;

            area = a;

            break;

        }

        spinlock_unlock(&a->lock);

    }

    if (!area) {

        /*

         * No area contained mapping for 'page'.

         * Signal page fault to low-level handler.

         */

        spinlock_unlock(&AS->lock);

        return 0;

    }

    /*

     * Note: area->lock is held.

     */

    /*

     * Decide if a frame needs to be allocated.

     * If so, allocate it and adjust area->mapping map.

     */

    if (area->mapping[vpn] == UNALLOCATED_PFN) {

        frame = frame_alloc(0, ONE_FRAME, NULL);

        memsetb(PA2KA(frame), FRAME_SIZE, 0);

        area->mapping[vpn] = frame / FRAME_SIZE;

        ASSERT(area->mapping[vpn] != UNALLOCATED_PFN);

    } else

        frame = area->mapping[vpn] * FRAME_SIZE;

    switch (area->type) {

        case AS_AREA_TEXT:

            flags = PAGE_EXEC | PAGE_READ | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;

            break;

        case AS_AREA_DATA:

        case AS_AREA_STACK:

            flags = PAGE_READ | PAGE_WRITE | PAGE_USER | PAGE_PRESENT | PAGE_CACHEABLE;

            break;

        default:

            panic("unexpected as_area_type_t %d", area->type);

    }

    /*

     * Map 'page' to 'frame'.

     * Note that TLB shootdown is not attempted as only new information is being

     * inserted into page tables.

     */

    page_mapping_insert(page, AS->asid, frame, flags, (__address) AS->ptl0);

    spinlock_unlock(&area->lock);

    spinlock_unlock(&AS->lock);

    return 1;

}

/** Install address space on CPU.

 *

 * @param as Address space.

 */

void as_install(as_t *as)

{

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&as->lock);

    ASSERT(as->ptl0);

    SET_PTL0_ADDRESS(as->ptl0);

    spinlock_unlock(&as->lock);

    interrupts_restore(ipl);

    /*

     * Perform architecture-specific steps.

     * (e.g. invalidate TLB, install ASID etc.)

     */

    as_install_arch(as);

    AS = as;

}