source: bootcd/isolinux/syslinux-6.03/core/mem/init.c

#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "malloc.h"
#include "core.h"
#include <syslinux/memscan.h>
#include <dprintf.h>

struct free_arena_header __core_malloc_head[NHEAP];

//static __hugebss char main_heap[128 << 10];
extern char __lowmem_heap[];
extern char free_high_memory[];

#define E820_MEM_MAX 0xfff00000 /* 4 GB - 1 MB */
int scan_highmem_area(void *data, addr_t start, addr_t len,
                      enum syslinux_memmap_types type)
{
        struct free_arena_header *fp;

        (void)data;

        dprintf("start = %x, len = %x, type = %d", start, len, type);

        if (start < 0x100000 || start > E820_MEM_MAX
                             || type != SMT_FREE)
                return 0;

        if (start < __com32.cs_memsize) {
                len -= __com32.cs_memsize - start;
                start = __com32.cs_memsize;
        }
        if (len > E820_MEM_MAX - start)
                len = E820_MEM_MAX - start;

        if (len >= 2 * sizeof(struct arena_header)) {
                fp = (struct free_arena_header *)start;
                fp->a.attrs = ARENA_TYPE_USED | (HEAP_MAIN << ARENA_HEAP_POS);
#ifdef DEBUG_MALLOC
                fp->a.magic = ARENA_MAGIC;
#endif
                ARENA_SIZE_SET(fp->a.attrs, len);
                dprintf("will inject a block start:0x%x size 0x%x", start, len);
                __inject_free_block(fp);
        }

        __com32.cs_memsize = start + len; /* update the HighMemSize */
        return 0;
}

#if 0
static void mpool_dump(enum heap heap)
{
        struct free_arena_header *head = &__core_malloc_head[heap];
        struct free_arena_header *fp;
        int size, type, i = 0;
        addr_t start, end;

        fp = head->next_free;
        while (fp != head) {
                size = ARENA_SIZE_GET(fp->a.attrs);
                type = ARENA_TYPE_GET(fp->a.attrs);
                start = (addr_t)fp;
                end = start + size;
                printf("area[%d]: start = 0x%08x, end = 0x%08x, type = %d\n",
                        i++, start, end, type);
                fp = fp->next_free;
        }
}
#endif

uint16_t *bios_free_mem;
void mem_init(void)
{
        struct free_arena_header *fp;
        int i;

        //dprintf("enter");

        /* Initialize the head nodes */
        fp = &__core_malloc_head[0];
        for (i = 0 ; i < NHEAP ; i++) {
        fp->a.next = fp->a.prev = fp->next_free = fp->prev_free = fp;
        fp->a.attrs = ARENA_TYPE_HEAD | (i << ARENA_HEAP_POS);
        fp->a.tag = MALLOC_HEAD;
        fp++;
        }
        
        //dprintf("__lowmem_heap = 0x%p bios_free = 0x%p",
        //      __lowmem_heap, *bios_free_mem);
        
        /* Initialize the lowmem heap */
        fp = (struct free_arena_header *)__lowmem_heap;
        fp->a.attrs = ARENA_TYPE_USED | (HEAP_LOWMEM << ARENA_HEAP_POS);
        ARENA_SIZE_SET(fp->a.attrs, (*bios_free_mem << 10) - (uintptr_t)fp);
#ifdef DEBUG_MALLOC
        fp->a.magic = ARENA_MAGIC;
#endif
        __inject_free_block(fp);

        /* Initialize the main heap */
        __com32.cs_memsize = (size_t)free_high_memory;
        syslinux_scan_memory(scan_highmem_area, NULL);
}