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/*

 * Copyright (C) 2001-2004 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 <arch/types.h>

#include <func.h>

#include <mm/heap.h>

#include <mm/frame.h>

#include <mm/page.h>

#include <mm/vm.h>

#include <arch/mm/page.h>

#include <config.h>

#include <memstr.h>

#include <panic.h>

#include <synch/spinlock.h>

count_t frames = 0;

count_t frames_free;

__u8 *frame_bitmap;

count_t frame_bitmap_octets;

/*

 * This is for kernel address space frames (allocated with FRAME_KA).

 * Their addresses may not interfere with user address space.

 */

__u8 *frame_kernel_bitmap;

count_t kernel_frames;

count_t kernel_frames_free;

static spinlock_t framelock;

void frame_init(void)

{

        if (config.cpu_active == 1) {

                /*

                 * The bootstrap processor will allocate all necessary memory for frame allocation.

                 */

                frames = config.memory_size / FRAME_SIZE;

                frame_bitmap_octets = frames / 8 + (frames % 8 > 0);

                frame_bitmap = (__u8 *) malloc(frame_bitmap_octets);

                if (!frame_bitmap)

                        panic("malloc/frame_bitmap\n");

                /*

                 * Mark all frames free.

                 */

                memsetb((__address) frame_bitmap, frame_bitmap_octets, 0);

                frames_free = frames;

        /*

         * Will be properly set up by architecture dependent frame init.

         */

        frame_kernel_bitmap = NULL;

        kernel_frames_free = 0;

        kernel_frames = 0; 

    }

    /*

     * No frame allocations/reservations  prior this point.

     */

    frame_arch_init();

    if (config.cpu_active == 1) {

                /*

                 * Create the memory address space map. Marked frames and frame

                 * regions cannot be used for allocation.

                 */

        frame_region_not_free(config.base, config.base + config.kernel_size);

    }

}

/*

 * Allocate a frame.

 */

__address frame_alloc(int flags)

{

    int i;

    pri_t pri;

    __u8 **frame_bitmap_ptr = &frame_bitmap;

    count_t *frames_ptr = &frames, *frames_free_ptr = &frames_free;

    if (flags & FRAME_KA) {

        frame_bitmap_ptr = &frame_kernel_bitmap;

        frames_ptr = &kernel_frames;

        frames_free_ptr = &kernel_frames_free;

    }

loop:

    pri = cpu_priority_high();

    spinlock_lock(&framelock);

    if (*frames_free_ptr) {

        for (i=0; i < *frames_ptr; i++) {

            int m, n;

            m = i / 8;

            n = i % 8;

            if (((*frame_bitmap_ptr)[m] & (1<<n)) == 0) {

                (*frame_bitmap_ptr)[m] |= (1<<n);

                *frames_free_ptr--;

                if (flags & FRAME_KA) {

                    /*

                     * frames_free_ptr points to kernel_frames_free

                     * It is still necessary to decrement frames_free.

                     */

                    frames_free--;

                }

                spinlock_unlock(&framelock);

                cpu_priority_restore(pri);

                if (flags & FRAME_KA) return PA2KA(i*FRAME_SIZE);

                return i*FRAME_SIZE;

            }

        }

        panic("frames_free inconsistent (%d)\n", frames_free);

    }

    spinlock_unlock(&framelock);

    cpu_priority_restore(pri);

    if (flags & FRAME_PANIC)

        panic("unable to allocate frame\n");

    /* TODO: implement sleeping logic here */

    panic("sleep not supported\n");

    goto loop;

}

/*

 * Free a frame.

 */

void frame_free(__address addr)

{

    pri_t pri;

    __u32 frame;

    count_t *frames_free_ptr = &frames_free, *frames_ptr = &frames;

    __u8 **frame_bitmap_ptr = &frame_bitmap;

    if (IS_KA(addr)) {

        frames_free_ptr = &kernel_frames_free;

        frame_bitmap_ptr = &frame_kernel_bitmap;

    }

    pri = cpu_priority_high();

    spinlock_lock(&framelock);

    frame = IS_KA(addr) ? KA2PA(addr) : addr;

    frame /= FRAME_SIZE;

    if (frame < *frames_ptr) {

        int m, n;

        m = frame / 8;

        n = frame % 8;

        if ((*frame_bitmap_ptr)[m] & (1<<n)) {

            (*frame_bitmap_ptr)[m] &= ~(1<<n);

            *frames_free_ptr++;

            if (IS_KA(addr)) {

                /*

                 * frames_free_ptr points to kernel_frames_free

                 * It is still necessary to increment frames_free.

                 */

                 frames_free++;

            }  

        }

        else panic("frame already free\n");

    }

    else panic("frame number too big\n");

    spinlock_unlock(&framelock);

    cpu_priority_restore(pri);

}

/*

 * Don't use this function for normal allocation. Use frame_alloc() instead.

 * Use this function to declare that some special frame is not free.

 */

void frame_not_free(__address addr)

{

    pri_t pri;

    __u32 frame;

    count_t *frames_ptr = &frames, *frames_free_ptr = &frames_free;

    __u8 **frame_bitmap_ptr = &frame_bitmap;

    pri = cpu_priority_high();

    spinlock_lock(&framelock);

    frame = IS_KA(addr) ? KA2PA(addr) : addr;

    frame /= FRAME_SIZE;

    if (frame < *frames_ptr) {

        int m, n;

        m = frame / 8;

        n = frame % 8;

        if (((*frame_bitmap_ptr)[m] & (1<<n)) == 0) {  

            (*frame_bitmap_ptr)[m] |= (1<<n);

            *frames_free_ptr--;

            if (IS_KA(addr)) {

                /*

                 * frames_free_ptr points to kernel_frames_free

                 * It is still necessary to decrement frames_free.

                 */

                frames_free--;

            }

        }

    }

    spinlock_unlock(&framelock);

    cpu_priority_restore(pri);

}

void frame_region_not_free(__address start, __address stop)

{

    __u32 i;

    start /= FRAME_SIZE;

    stop /= FRAME_SIZE;

    for (i = start; i <= stop; i++)

        frame_not_free(i * FRAME_SIZE);

}