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/*

 * Copyright (C) 2001-2005 Jakub Jermar

 * Copyright (C) 2005 Sergey Bondari

 * 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.

 */

/*

 * Locking order

 *

 * In order to access particular zone, the process must first lock

 * the zones.lock, then lock the zone and then unlock the zones.lock.

 * This insures, that we can fiddle with the zones in runtime without

 * affecting the processes.

 *

 */

#include <typedefs.h>

#include <arch/types.h>

#include <mm/frame.h>

#include <mm/as.h>

#include <panic.h>

#include <debug.h>

#include <adt/list.h>

#include <synch/spinlock.h>

#include <arch/asm.h>

#include <arch.h>

#include <print.h>

#include <align.h>

#include <mm/slab.h>

typedef struct {

    count_t refcount;   /**< tracking of shared frames  */

    __u8 buddy_order;   /**< buddy system block order */

    link_t buddy_link;  /**< link to the next free block inside one order */

    void *parent;           /**< If allocated by slab, this points there */

}frame_t;

typedef struct {

    SPINLOCK_DECLARE(lock); /**< this lock protects everything below */

    pfn_t base; /**< frame_no of the first frame in the frames array */

    count_t count;          /**< Size of zone */

    frame_t *frames;    /**< array of frame_t structures in this zone */

    count_t free_count; /**< number of free frame_t structures */

    count_t busy_count; /**< number of busy frame_t structures */

    buddy_system_t * buddy_system; /**< buddy system for the zone */

    int flags;

}zone_t;

/*

 * The zoneinfo.lock must be locked when accessing zoneinfo structure.

 * Some of the attributes in zone_t structures are 'read-only'

 */

struct {

    SPINLOCK_DECLARE(lock);

    int count;

    zone_t *info[ZONES_MAX];

}zones;

/*********************************/

/* Helper functions */

static inline index_t frame_index(zone_t *zone, frame_t *frame)

{

    return (index_t)(frame - zone->frames);

}

static inline index_t frame_index_abs(zone_t *zone, frame_t *frame)

{

    return (index_t)(frame - zone->frames) + zone->base;

}

static inline int frame_index_valid(zone_t *zone, index_t index)

{

    return index >= 0 && index < zone->count;

}

/** Compute pfn_t from frame_t pointer & zone pointer */

static index_t make_frame_index(zone_t *zone, frame_t *frame)

{

    return frame - zone->frames;

}

/** Initialize frame structure

 *

 * Initialize frame structure.

 *

 * @param frame Frame structure to be initialized.

 */

static void frame_initialize(frame_t *frame)

{

    frame->refcount = 1;

    frame->buddy_order = 0;

}

/*************************************/

/* Zoneinfo functions */

/**

 * Insert-sort zone into zones list

 */

static void zones_add_zone(zone_t *zone)

{

    int i;

    spinlock_lock(&zones.lock);

    /* Try to merge */

    if (zone->flags & ZONE_JOIN) {

        for (i=0; i < zones.count; i++) {

            spinlock_lock(&zones.info[i]->lock);

            /* Join forward, join backward */

            panic("Not implemented");

            spinlock_unlock(&zones.info[i]->lock);

        }

        spinlock_unlock(&zones.lock);

    } else {

        if (zones.count+1 == ZONES_MAX)

            panic("Maximum zone(%d) count exceeded.", ZONES_MAX);

        zones.info[zones.count++] = zone;

    }

    spinlock_unlock(&zones.lock);

}

/**

 * Try to find a zone where can we find the frame

 *

 * @param hint Start searching in zone 'hint'

 * @param lock Lock zone if true

 *

 * Assume interrupts disable

 */

static zone_t * find_zone_and_lock(pfn_t frame, int *pzone)

{

    int i;

    int hint = pzone ? *pzone : 0;

    zone_t *z;

    spinlock_lock(&zones.lock);

    if (hint >= zones.count || hint < 0)

        hint = 0;

    i = hint;

    do {

        z = zones.info[i];

        spinlock_lock(&z->lock);

        if (z->base <= frame && z->base + z->count > frame) {

            spinlock_unlock(&zones.lock); /* Unlock the global lock */

            if (pzone)

                *pzone = i;

            return z;

        }

        spinlock_unlock(&z->lock);

        i++;

        if (i >= zones.count)

            i = 0;

    } while(i != hint);

    spinlock_unlock(&zones.lock);

    return NULL;

}

/**

 * Find AND LOCK zone that can allocate order frames

 *

 * Assume interrupts are disabled!!

 *

 * @param pzone Pointer to preferred zone or NULL, on return contains zone number

 */

static zone_t * find_free_zone_lock(__u8 order, int *pzone)

{

    int i;

    zone_t *z;

    int hint = pzone ? *pzone : 0;

    spinlock_lock(&zones.lock);

    if (hint >= zones.count)

        hint = 0;

    i = hint;

    do {

        z = zones.info[i];

        spinlock_lock(&z->lock);

        /* Check if the zone has 2^order frames area available  */

        if (buddy_system_can_alloc(z->buddy_system, order)) {

            spinlock_unlock(&zones.lock);

            if (pzone)

                *pzone = i;

            return z;

        }

        spinlock_unlock(&z->lock);

        if (++i >= zones.count)

            i = 0;

    } while(i != hint);

    spinlock_unlock(&zones.lock);

    return NULL;

}

/********************************************/

/* Buddy system functions */

/** Buddy system find_block implementation

 *

 * Find block that is parent of current list.

 * That means go to lower addresses, until such block is found

 *

 * @param order - Order of parent must be different then this parameter!!

 */

static link_t *zone_buddy_find_block(buddy_system_t *b, link_t *child,

                     __u8 order)

{

    frame_t * frame;

    zone_t * zone;

    index_t index;

    frame = list_get_instance(child, frame_t, buddy_link);

    zone = (zone_t *) b->data;

    index = frame_index(zone, frame);

    do {

        if (zone->frames[index].buddy_order != order) {

            return &zone->frames[index].buddy_link;

        }

    } while(index-- > 0);

    return NULL;

}

/** 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

 */

static link_t * zone_buddy_find_buddy(buddy_system_t *b, link_t * block)

{

    frame_t * frame;

    zone_t * zone;

    index_t index;

    bool is_left, is_right;

    frame = list_get_instance(block, frame_t, buddy_link);

    zone = (zone_t *) b->data;

    ASSERT(IS_BUDDY_ORDER_OK(frame_index_abs(zone, frame), frame->buddy_order));

    is_left = IS_BUDDY_LEFT_BLOCK_ABS(zone, frame);

    is_right = IS_BUDDY_RIGHT_BLOCK_ABS(zone, frame);

    ASSERT(is_left ^ is_right);

    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

 */

static 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)

 */

static 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

 */

static 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

 */

static __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

 *

 */

static 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;

}

/** Buddy system mark_available implementation

 *

 * @param b Buddy system

 * @param block Buddy system block

 *

 */

static void zone_buddy_mark_available(buddy_system_t *b, link_t * block) {

    frame_t * frame;

    frame = list_get_instance(block, frame_t, buddy_link);

    frame->refcount = 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,

    .mark_available = zone_buddy_mark_available,

    .find_block = zone_buddy_find_block

};

/*************************************/

/* Zone functions */

/** Allocate frame in particular zone

 *

 * Assume zone is locked

 *

 * @return Frame index in zone

 */

static pfn_t zone_frame_alloc(zone_t *zone,__u8 order, int flags, int *status)

{

    pfn_t v;

    link_t *tmp;

    frame_t *frame;

    /* 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 = make_frame_index(zone, frame);

    return v;

}

/** Free frame from zone

 *

 * Assume zone is locked

 */

static void zone_frame_free(zone_t *zone, index_t frame_idx)

{

    frame_t *frame;

    __u8 order;

    frame = &zone->frames[frame_idx];

    /* remember frame order */

    order = frame->buddy_order;

    ASSERT(frame->refcount);

    if (!--frame->refcount) {

        buddy_system_free(zone->buddy_system, &frame->buddy_link);

    }

    /* Update zone information. */

    zone->free_count += (1 << order);

    zone->busy_count -= (1 << order);

}

/** Return frame from zone */

static frame_t * zone_get_frame(zone_t *zone, index_t frame_idx)

{

    ASSERT(frame_idx < zone->count);

    return &zone->frames[frame_idx];

}

/** Mark frame in zone unavailable to allocation */

static void zone_mark_unavailable(zone_t *zone, index_t frame_idx)

{

    frame_t *frame;

    link_t *link;

    frame = zone_get_frame(zone, frame_idx);

    link = buddy_system_alloc_block(zone->buddy_system,

                    &frame->buddy_link);

    ASSERT(link);

    zone->free_count--;

}

/** 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 conffram Address of configuration frame

 * @param flags Zone flags.

 *

 * @return Initialized zone.

 */

static zone_t * zone_construct(pfn_t start, count_t count,

                   zone_t *z, int flags)

{

    int i;

    __u8 max_order;

    spinlock_initialize(&z->lock, "zone_lock");

    z->base = start;

    z->count = count;

    z->flags = flags;

    z->free_count = count;

    z->busy_count = 0;

    /*

     * Compute order for buddy system, initialize

     */

    for (max_order = 0; count >> max_order; max_order++)

        ;

    z->buddy_system = (buddy_system_t *)&z[1];

    buddy_system_create(z->buddy_system, max_order,

                &zone_buddy_system_operations,

                (void *) z);

    /* Allocate frames _after_ the conframe */

    /* Check sizes */

    z->frames = (frame_t *)((void *)z->buddy_system+buddy_conf_size(max_order));

    for (i = 0; i<count; i++) {

        frame_initialize(&z->frames[i]);

    }

    /* Stuffing frames */

    for (i = 0; i < count; i++) {

        z->frames[i].refcount = 0;

        buddy_system_free(z->buddy_system, &z->frames[i].buddy_link);

    }

    return z;

}

/** Compute configuration data size for zone */

__address zone_conf_size(pfn_t start, count_t count)

{

    int size = sizeof(zone_t) + count*sizeof(frame_t);

    int max_order;

    for (max_order = 0; count >> max_order; max_order++)

        ;

    size += buddy_conf_size(max_order);

    return size;

}

/** Create and add zone to system

 *

 * @param confframe Where configuration frame is supposed to be.

 *                  Always check, that we will not disturb the kernel and possibly init.

 *                  If confframe is given _outside_ this zone, it is expected,

 *                  that the area is already marked BUSY and big enough

 *                  to contain zone_conf_size() amount of data

 */

void zone_create(pfn_t start, count_t count, pfn_t confframe, int flags)

{

    zone_t *z;

    __address addr,endaddr;

    count_t confcount;

    int i;

    /* Theoretically we could have here 0, practically make sure

     * nobody tries to do that. If some platform requires, remove

     * the assert

     */

    ASSERT(confframe);

    /* If conframe is supposed to be inside our zone, then make sure

     * it does not span kernel & init

     */

    confcount = SIZE2FRAMES(zone_conf_size(start,count));

    if (confframe >= start && confframe < start+count) {

        for (;confframe < start+count;confframe++) {

            addr = PFN2ADDR(confframe);

            endaddr =  PFN2ADDR (confframe + confcount);

            if (overlaps(addr, endaddr, KA2PA(config.base),

                     KA2PA(config.base+config.kernel_size)))

                continue;

            if (config.init_addr)

                if (overlaps(addr,endaddr,

                         KA2PA(config.init_addr),

                         KA2PA(config.init_addr+config.init_size)))

                    continue;

            break;

        }

        if (confframe >= start+count)

            panic("Cannot find configuration data for zone.");

    }

    z = zone_construct(start, count, (zone_t *)PA2KA(PFN2ADDR(confframe)), flags);

    zones_add_zone(z);

    /* If confdata in zone, mark as unavailable */

    if (confframe >= start && confframe < start+count)

        for (i=confframe; i<confframe+confcount; i++) {

            zone_mark_unavailable(z, i - z->base);

        }

}

/***************************************/

/* Frame functions */

/** Set parent of frame */

void frame_set_parent(pfn_t pfn, void *data, int hint)

{

    zone_t *zone = find_zone_and_lock(pfn, &hint);

    ASSERT(zone);

    zone_get_frame(zone, pfn-zone->base)->parent = data;

    spinlock_unlock(&zone->lock);

}

void * frame_get_parent(pfn_t pfn, int hint)

{

    zone_t *zone = find_zone_and_lock(pfn, &hint);

    void *res;

    ASSERT(zone);

    res = zone_get_frame(zone, pfn - zone->base)->parent;

    spinlock_unlock(&zone->lock);

    return res;

}

/** 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.

 * @param pzone Preferred zone

 *

 * @return Allocated frame.

 */

pfn_t frame_alloc_generic(__u8 order, int flags, int * status, int *pzone)

{

    ipl_t ipl;

    int freed;

    pfn_t v;

    zone_t *zone;

loop:

    ipl = interrupts_disable();

    /*

     * First, find suitable frame zone.

     */

    zone = find_free_zone_lock(order,pzone);

    /* If no memory, reclaim some slab memory,

       if it does not help, reclaim all */

    if (!zone && !(flags & FRAME_NO_RECLAIM)) {

        freed = slab_reclaim(0);

        if (freed)

            zone = find_free_zone_lock(order,pzone);

        if (!zone) {

            freed = slab_reclaim(SLAB_RECLAIM_ALL);

            if (freed)

                zone = find_free_zone_lock(order,pzone);

        }

    }

    if (!zone) {

        if (flags & FRAME_PANIC)

            panic("Can't allocate frame.\n");

        /*

         * TODO: Sleep until frames are available again.

         */

        interrupts_restore(ipl);

        if (flags & FRAME_ATOMIC) {

            ASSERT(status != NULL);

            if (status)

                *status = FRAME_NO_MEMORY;

            return NULL;

        }

        panic("Sleep not implemented.\n");

        goto loop;

    }

    v = zone_frame_alloc(zone,order,flags,status);

    v += zone->base;

    spinlock_unlock(&zone->lock);

    interrupts_restore(ipl);

    if (status)

        *status = FRAME_OK;

    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 frame Frame no to be freed.

 */

void frame_free(pfn_t pfn)

{

    ipl_t ipl;

    zone_t *zone;

    ipl = interrupts_disable();

    /*

     * First, find host frame zone for addr.

     */

    zone = find_zone_and_lock(pfn,NULL);

    ASSERT(zone);

    zone_frame_free(zone, pfn-zone->base);

    spinlock_unlock(&zone->lock);

    interrupts_restore(ipl);

}

/** Mark given range unavailable in frame zones */

void frame_mark_unavailable(pfn_t start, count_t count)

{

    int i;

    zone_t *zone;

    int prefzone = 0;

    for (i=0; i<count; i++) {

        zone = find_zone_and_lock(start+i,&prefzone);

        if (!zone) /* PFN not found */

            continue;

        zone_mark_unavailable(zone, start+i-zone->base);

        spinlock_unlock(&zone->lock);

    }

}

/** Initialize physical memory management

 *

 * Initialize physical memory managemnt.

 */

void frame_init(void)

{

    if (config.cpu_active == 1) {

        zones.count = 0;

        spinlock_initialize(&zones.lock,"zones_glob_lock");

    }

    /* Tell the architecture to create some memory */

    frame_arch_init();

    if (config.cpu_active == 1) {

        frame_mark_unavailable(ADDR2PFN(KA2PA(config.base)),

                       SIZE2FRAMES(config.kernel_size));

        if (config.init_size > 0)

            frame_mark_unavailable(ADDR2PFN(KA2PA(config.init_addr)),

                           SIZE2FRAMES(config.init_size));

    }

}

/** Prints list of zones

 *

 */

void zone_print_list(void) {

    zone_t *zone = NULL;

    int i;

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&zones.lock);

    printf("Base address\tFree Frames\tBusy Frames\n");

    printf("------------\t-----------\t-----------\n");

    for (i=0;i<zones.count;i++) {

        zone = zones.info[i];

        spinlock_lock(&zone->lock);

        printf("%L\t%d\t\t%d\n",PFN2ADDR(zone->base),

               zone->free_count, zone->busy_count);

        spinlock_unlock(&zone->lock);

    }

    spinlock_unlock(&zones.lock);

    interrupts_restore(ipl);

}

/** Prints zone details

 *

 * @param base Zone base address

 */

void zone_print_one(int znum) {

    zone_t *zone = NULL;

    ipl_t ipl;

    ipl = interrupts_disable();

    spinlock_lock(&zones.lock);

    if (znum >= zones.count || znum < 0) {

        printf("Zone number out of bounds.\n");

        spinlock_unlock(&zones.lock);

        interrupts_restore(ipl);

        return;

    }

    zone = zones.info[znum];

    spinlock_lock(&zone->lock);

    printf("Memory zone information\n\n");

    printf("Zone base address: %P\n", PFN2ADDR(zone->base));

    printf("Zone size: %d frames (%dK)\n", zone->count, ((zone->count) * FRAME_SIZE) >> 10);

    printf("Allocated space: %d frames (%dK)\n", zone->busy_count, (zone->busy_count * FRAME_SIZE) >> 10);

    printf("Available space: %d (%dK)\n", zone->free_count, (zone->free_count * FRAME_SIZE) >> 10);

    printf("\nBuddy allocator structures:\n\n");

    buddy_system_structure_print(zone->buddy_system, FRAME_SIZE);

    spinlock_unlock(&zone->lock);

    spinlock_unlock(&zones.lock);

    interrupts_restore(ipl);

}