source: mainline/generic/src/mm/frame.c@ d43d2f7

/*
 * 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 <typedefs.h>
#include <arch/types.h>
#include <mm/heap.h>
#include <mm/frame.h>
#include <mm/vm.h>
#include <panic.h>
#include <debug.h>
#include <list.h>
#include <synch/spinlock.h>
#include <arch/asm.h>
#include <arch.h>
#include <print.h>
#include <align.h>

spinlock_t zone_head_lock;       /**< this lock protects zone_head list */
link_t zone_head;                /**< list of all zones in the system */

/** Blacklist containing non-available areas of memory.
 *
 * This blacklist is used to exclude frames that cannot be allocated
 * (e.g. kernel memory) from available memory map.
 */
region_t zone_blacklist[ZONE_BLACKLIST_SIZE];
count_t zone_blacklist_count = 0;

static struct buddy_system_operations  zone_buddy_system_operations = {
        .find_buddy = zone_buddy_find_buddy,
        .bisect = zone_buddy_bisect,
        .coalesce = zone_buddy_coalesce,
        .set_order = zone_buddy_set_order,
        .get_order = zone_buddy_get_order,
        .mark_busy = zone_buddy_mark_busy,
};

/** Initialize physical memory management
 *
 * Initialize physical memory managemnt.
 */
void frame_init(void)
{
        if (config.cpu_active == 1) {
                zone_init();
                frame_region_not_free(KA2PA(config.base), config.kernel_size);
        }

        frame_arch_init();
}

/** Allocate power-of-two frames of physical memory.
 *
 * @param flags Flags for host zone selection and address processing.
 * @param order Allocate exactly 2^order frames.
 *
 * @return Allocated frame.
 */
__address frame_alloc(int flags, __u8 order) 
{
        ipl_t ipl;
        link_t *cur, *tmp;
        zone_t *z;
        zone_t *zone = NULL;
        frame_t *frame = NULL;
        __address v;
        
loop:
        ipl = interrupts_disable();
        spinlock_lock(&zone_head_lock);

        /*
         * First, find suitable frame zone.
         */
        for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
                z = list_get_instance(cur, zone_t, link);
                
                spinlock_lock(&z->lock);

                /* Check if the zone has 2^order frames area available  */
                if (buddy_system_can_alloc(z->buddy_system, order)) {
                        zone = z;
                        break;
                }
                
                spinlock_unlock(&z->lock);
        }
        
        if (!zone) {
                if (flags & FRAME_PANIC)
                        panic("Can't allocate frame.\n");
                
                /*
                 * TODO: Sleep until frames are available again.
                 */
                spinlock_unlock(&zone_head_lock);
                interrupts_restore(ipl);

                panic("Sleep not implemented.\n");
                goto loop;
        }
                

        /* Allocate frames from zone buddy system */
        tmp = buddy_system_alloc(zone->buddy_system, order);
        
        ASSERT(tmp);
        
        /* Update zone information. */
        zone->free_count -= (1 << order);
        zone->busy_count += (1 << order);

        /* Frame will be actually a first frame of the block. */
        frame = list_get_instance(tmp, frame_t, buddy_link);
        
        /* get frame address */
        v = FRAME2ADDR(zone, frame);

        spinlock_unlock(&zone->lock);
        spinlock_unlock(&zone_head_lock);
        interrupts_restore(ipl);


        if (flags & FRAME_KA)
                v = PA2KA(v);
        
        return v;
}

/** Free a frame.
 *
 * Find respective frame structrue for supplied addr.
 * Decrement frame reference count.
 * If it drops to zero, move the frame structure to free list.
 *
 * @param addr Address of the frame to be freed. It must be a multiple of FRAME_SIZE.
 */
void frame_free(__address addr)
{
        ipl_t ipl;
        link_t *cur;
        zone_t *z;
        zone_t *zone = NULL;
        frame_t *frame;
        ASSERT(addr % FRAME_SIZE == 0);
        
        ipl = interrupts_disable();
        spinlock_lock(&zone_head_lock);
        
        /*
         * First, find host frame zone for addr.
         */
        for (cur = zone_head.next; cur != &zone_head; cur = cur->next) {
                z = list_get_instance(cur, zone_t, link);
                
                spinlock_lock(&z->lock);
                
                if (IS_KA(addr))
                        addr = KA2PA(addr);
                
                /*
                 * Check if addr belongs to z.
                 */
                if ((addr >= z->base) && (addr <= z->base + (z->free_count + z->busy_count) * FRAME_SIZE)) {
                        zone = z;
                        break;
                }
                spinlock_unlock(&z->lock);
        }
        
        ASSERT(zone != NULL);
        
        frame = ADDR2FRAME(zone, addr);

        ASSERT(frame->refcount);

        if (!--frame->refcount) {
                buddy_system_free(zone->buddy_system, &frame->buddy_link);
        }

        /* Update zone information. */
        zone->free_count += (1 << frame->buddy_order);
        zone->busy_count -= (1 << frame->buddy_order);
        
        spinlock_unlock(&zone->lock);
        spinlock_unlock(&zone_head_lock);
        interrupts_restore(ipl);
}

/** Mark frame region not free.
 *
 * Mark frame region not free.
 *
 * @param base Base address of non-available region.
 * @param size Size of non-available region.
 */
void frame_region_not_free(__address base, size_t size)
{
        index_t index;
        index = zone_blacklist_count++;

        /* Force base to the nearest lower address frame boundary. */
        base &= ~(FRAME_SIZE - 1);
        /* Align size to frame boundary. */
        size = ALIGN(size, FRAME_SIZE);

        ASSERT(zone_blacklist_count <= ZONE_BLACKLIST_SIZE);
        zone_blacklist[index].base = base;
        zone_blacklist[index].size = size;
}


/** Initialize zonekeeping
 *
 * Initialize zonekeeping.
 */
void zone_init(void)
{
        spinlock_initialize(&zone_head_lock);
        list_initialize(&zone_head);
}

/** Create frame zones in region of available memory.
 *
 * Avoid any black listed areas of non-available memory.
 * Assume that the black listed areas cannot overlap
 * one another or cross available memory region boundaries.
 *
 * @param base Base address of available memory region.
 * @param size Size of the region.
 */
void zone_create_in_region(__address base, size_t size) {
        int i;
        zone_t * z;
        __address s;
        size_t sz;
        
        ASSERT(base % FRAME_SIZE == 0);
        ASSERT(size % FRAME_SIZE == 0);
        
        if (!size)
                return;

        for (i = 0; i < zone_blacklist_count; i++) {
                if (zone_blacklist[i].base >= base && zone_blacklist[i].base < base + size) {
                        s = base; sz = zone_blacklist[i].base - base;
                        ASSERT(base != s || sz != size);
                        zone_create_in_region(s, sz);
                        
                        s = zone_blacklist[i].base + zone_blacklist[i].size;
                        sz = (base + size) - (zone_blacklist[i].base + zone_blacklist[i].size);
                        ASSERT(base != s || sz != size);
                        zone_create_in_region(s, sz);
                        return;
                
                }
        }
        
        z = zone_create(base, size, 0);

        if (!z) {
                panic("Cannot allocate zone (%dB).\n", size);
        }
        
        zone_attach(z);
}


/** Create frame zone
 *
 * Create new frame zone.
 *
 * @param start Physical address of the first frame within the zone.
 * @param size Size of the zone. Must be a multiple of FRAME_SIZE.
 * @param flags Zone flags.
 *
 * @return Initialized zone.
 */
zone_t * zone_create(__address start, size_t size, int flags)
{
        zone_t *z;
        count_t cnt;
        int i;
        __u8 max_order;

        ASSERT(start % FRAME_SIZE == 0);
        ASSERT(size % FRAME_SIZE == 0);
        
        cnt = size / FRAME_SIZE;
        
        z = (zone_t *) early_malloc(sizeof(zone_t));
        if (z) {
                link_initialize(&z->link);
                spinlock_initialize(&z->lock);
        
                z->base = start;
                z->flags = flags;

                z->free_count = cnt;
                z->busy_count = 0;
                
                z->frames = (frame_t *) early_malloc(cnt * sizeof(frame_t));
                if (!z->frames) {
                        early_free(z);
                        return NULL;
                }
                
                for (i = 0; i<cnt; i++) {
                        frame_initialize(&z->frames[i], z);
                }
                
                /*
                 * Create buddy system for the zone
                 */
                for (max_order = 0; cnt >> max_order; max_order++)
                        ;
                z->buddy_system = buddy_system_create(max_order, &zone_buddy_system_operations, (void *) z);
                
                /* Stuffing frames */
                for (i = 0; i<cnt; i++) {
                        z->frames[i].refcount = 0;
                        buddy_system_free(z->buddy_system, &z->frames[i].buddy_link);   
                }
        }
        return z;
}

/** Attach frame zone
 *
 * Attach frame zone to zone list.
 *
 * @param zone Zone to be attached.
 */
void zone_attach(zone_t *zone)
{
        ipl_t ipl;
        
        ipl = interrupts_disable();
        spinlock_lock(&zone_head_lock);
        
        list_append(&zone->link, &zone_head);
        
        spinlock_unlock(&zone_head_lock);
        interrupts_restore(ipl);
}

/** Initialize frame structure
 *
 * Initialize frame structure.
 *
 * @param frame Frame structure to be initialized.
 * @param zone Host frame zone.
 */
void frame_initialize(frame_t *frame, zone_t *zone)
{
        frame->refcount = 1;
        frame->buddy_order = 0;
}


/** Buddy system find_buddy implementation
 *
 * @param b Buddy system.
 * @param block Block for which buddy should be found
 *
 * @return Buddy for given block if found
 */
link_t * zone_buddy_find_buddy(buddy_system_t *b, link_t * block) {
        frame_t * frame;
        zone_t * zone;
        count_t index;
        bool is_left, is_right;

        frame = list_get_instance(block, frame_t, buddy_link);
        zone = (zone_t *) b->data;
        
        is_left = IS_BUDDY_LEFT_BLOCK(zone, frame);
        is_right = !is_left;
        
        /*
         * test left buddy
         */
        if (is_left) {
                index = (FRAME_INDEX(zone, frame)) + (1 << frame->buddy_order);
        } else if (is_right) {
                index = (FRAME_INDEX(zone, frame)) - (1 << frame->buddy_order);
        }
        
        if (FRAME_INDEX_VALID(zone, index)) {
                if (    zone->frames[index].buddy_order == frame->buddy_order && 
                        zone->frames[index].refcount == 0) {
                        return &zone->frames[index].buddy_link;
                }
        }
        
        return NULL;    
}

/** Buddy system bisect implementation
 *
 * @param b Buddy system.
 * @param block Block to bisect
 *
 * @return right block
 */
link_t * zone_buddy_bisect(buddy_system_t *b, link_t * block) {
        frame_t * frame_l, * frame_r;
        frame_l = list_get_instance(block, frame_t, buddy_link);
        frame_r = (frame_l + (1 << (frame_l->buddy_order - 1)));
        return &frame_r->buddy_link;
}

/** Buddy system coalesce implementation
 *
 * @param b Buddy system.
 * @param block_1 First block
 * @param block_2 First block's buddy
 *
 * @return Coalesced block (actually block that represents lower address)
 */
link_t * zone_buddy_coalesce(buddy_system_t *b, link_t * block_1, link_t * block_2) {
        frame_t * frame1, * frame2;
        frame1 = list_get_instance(block_1, frame_t, buddy_link);
        frame2 = list_get_instance(block_2, frame_t, buddy_link);
        return frame1 < frame2 ? block_1 : block_2;
}

/** Buddy system set_order implementation
 *
 * @param b Buddy system.
 * @param block Buddy system block
 * @param order Order to set
 */
void zone_buddy_set_order(buddy_system_t *b, link_t * block, __u8 order) {
        frame_t * frame;
        frame = list_get_instance(block, frame_t, buddy_link);
        frame->buddy_order = order;
}

/** Buddy system get_order implementation
 *
 * @param b Buddy system.
 * @param block Buddy system block
 *
 * @return Order of block
 */
__u8 zone_buddy_get_order(buddy_system_t *b, link_t * block) {
        frame_t * frame;
        frame = list_get_instance(block, frame_t, buddy_link);
        return frame->buddy_order;
}

/** Buddy system mark_busy implementation
 *
 * @param b Buddy system
 * @param block Buddy system block
 *
 */
void zone_buddy_mark_busy(buddy_system_t *b, link_t * block) {
        frame_t * frame;
        frame = list_get_instance(block, frame_t, buddy_link);
        frame->refcount = 1;
}