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check bitmap boundary

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This commit is contained in:
Stefan Lankes 2014-12-27 23:26:31 +01:00
parent 2214869297
commit 0b49fb79a9
1 changed files with 11 additions and 3 deletions
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14
mm/memory.c
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@ -169,22 +169,27 @@ int memory_init(void)
// parse multiboot information for available memory
if (mb_info) {
if (mb_info->flags & MULTIBOOT_INFO_MEM_MAP) {
size_t end_addr;
multiboot_memory_map_t* mmap = (multiboot_memory_map_t*) ((size_t) mb_info->mmap_addr);
multiboot_memory_map_t* mmap_end = (void*) ((size_t) mb_info->mmap_addr + mb_info->mmap_length);
// mark available memory as free
while (mmap < mmap_end) {
if (mmap->type == MULTIBOOT_MEMORY_AVAILABLE) {
for (addr=mmap->addr; addr < mmap->addr + mmap->len; addr += PAGE_SIZE) {
/* set the available memory as "unused" */
addr = mmap->addr;
end_addr = addr + mmap->len;
while ((addr < end_addr) && (addr < (BITMAP_SIZE*8*PAGE_SIZE))) {
page_clear_mark(addr >> PAGE_BITS);
addr += PAGE_SIZE;
atomic_int32_inc(&total_pages);
atomic_int32_inc(&total_available_pages);
}
}
mmap++;
}
}
else if (mb_info->flags & MULTIBOOT_INFO_MEM) {
} else if (mb_info->flags & MULTIBOOT_INFO_MEM) {
size_t page;
size_t pages_lower = mb_info->mem_lower >> 2; /* KiB to page number */
size_t pages_upper = mb_info->mem_upper >> 2;
@ -192,6 +197,9 @@ int memory_init(void)
for (page=0; page<pages_lower; page++)
page_clear_mark(page);
if (pages_upper > BITMAP_SIZE*8-256)
pages_upper = BITMAP_SIZE*8-256;
for (page=0; page<pages_upper; page++)
page_clear_mark(page + 256); /* 1 MiB == 256 pages offset */