void multiboot_mmap(paddr_t mb_info_phys) {
vaddr_t mb_info = PHYSTOKBSS(mb_info_phys);
vmmap(KTEXT, mb_info + 4);
size_t mb_size = *((size_t *)mb_info);
vmmap(KTEXT, mb_info + mb_size);
// the first 8 bytes are size + reserved
struct multiboot_tag *tag = (struct multiboot_tag *)(mb_info + 8);
while (tag->type != MULTIBOOT_TAG_TYPE_END) {
if (tag->type != MULTIBOOT_TAG_TYPE_BASIC_MEMINFO) {
tag = (struct multiboot_tag *)((vaddr_t)tag + ((tag->size + 7) & (uint32_t)~7));
continue;
}
struct multiboot_tag_basic_meminfo *meminfo = (struct multiboot_tag_basic_meminfo *)tag;
/* mem_upper is the amount of upper memory in kb */
/* upper memory begins at 1M (hence + 1024) */
HardwareInfo.mem_max = (meminfo->mem_upper + 1024) * 1024;
frame_alloc_init(HardwareInfo.mem_max);
break;
}
tag = (struct multiboot_tag *)(mb_info + 8);
while (tag->type != MULTIBOOT_TAG_TYPE_END) {
if (tag->type == MULTIBOOT_TAG_TYPE_MMAP) {
struct multiboot_tag_mmap *mmap = (struct multiboot_tag_mmap *)tag;
struct multiboot_mmap_entry *entry = (struct multiboot_mmap_entry *)&mmap->entries;
for (int i = 0; i < (int)tag->size; i += mmap->entry_size) {
if (entry->type == MULTIBOOT_MEMORY_AVAILABLE) {
frame_clear_range((paddr_t)entry->addr, (paddr_t)entry->addr + (paddr_t)entry->len);
}
entry = (struct multiboot_mmap_entry *)((vaddr_t)entry + (vaddr_t)mmap->entry_size);
}
}
if (tag->type == MULTIBOOT_TAG_TYPE_MODULE) {
struct multiboot_tag_module *mod = (struct multiboot_tag_module *)tag;
InitrdStart = mod->mod_start;
InitrdEnd = mod->mod_end;
/* In order to load the initrd, we map it into kernel space,
then extend the kernel brk to ensure malloc can't access it */
frame_set_range(InitrdStart, InitrdEnd);
Initrd = (cpiohdr_t *)PHYSTOKBSS(InitrdStart);
}
tag = (struct multiboot_tag *)((vaddr_t)tag + ((tag->size + 7) & (uint32_t)~7));
}
}
void *mmap(void *addr, size_t size, int prot, int flags, handle_t f, off_t offset) {
if (flags & MAP_ANONYMOUS) {
addr = vmalloc(addr, size, MEM_RESERVE | MEM_COMMIT, map_protect(prot), 'MMAP');
} else {
addr = vmmap(addr, size, map_protect(prot), f, offset);
if (!addr) return MAP_FAILED;
}
return addr;
}