- x86_page_table* l1pt = (x86_page_table*)L1_BASE_VADDR;
- x86_page_table* l2pt = (x86_page_table*)L2_VADDR(l1_inx);
-
- // See if attr make sense
- assert(attr <= 128);
-
- if (!l1pt->entry[l1_inx]) {
- x86_page_table* new_l1pt_pa = pmm_alloc_page();
-
- // 物理内存已满!
- if (!new_l1pt_pa) {
- return 0;
- }
-
- l1pt->entry[l1_inx] = NEW_L1_ENTRY(attr, new_l1pt_pa);
- memset((void*)L2_VADDR(l1_inx), 0, PG_SIZE);
- }
-
- x86_pte_t l2pte = l2pt->entry[l2_inx];
- if (l2pte) {
- if (!forced) {
- return 0;
- }
- if (HAS_FLAGS(l2pte, PG_PRESENT)) {
- assert_msg(pmm_free_page(GET_PG_ADDR(l2pte)), "fail to release physical page");
- }
- }
-
- l2pt->entry[l2_inx] = NEW_L2_ENTRY(attr, pa);
-
- return 1;
-}
-
-void*
-vmm_map_page(void* va, void* pa, pt_attr tattr)
-{
- // 显然,对空指针进行映射没有意义。
- if (!pa || !va) {
- return NULL;
- }
-
- assert(((uintptr_t)va & 0xFFFU) == 0) assert(((uintptr_t)pa & 0xFFFU) == 0);
-
- uint32_t l1_index = L1_INDEX(va);
- uint32_t l2_index = L2_INDEX(va);
- x86_page_table* l1pt = (x86_page_table*)L1_BASE_VADDR;
-
- // 在页表与页目录中找到一个可用的空位进行映射(位于va或其附近)
- x86_pte_t l1pte = l1pt->entry[l1_index];
- x86_page_table* l2pt = (x86_page_table*)L2_VADDR(l1_index);
- while (l1pte && l1_index < PG_MAX_ENTRIES) {
- if (l2_index == PG_MAX_ENTRIES) {
- l1_index++;
- l2_index = 0;
- l1pte = l1pt->entry[l1_index];
- l2pt = (x86_page_table*)L2_VADDR(l1_index);
- }
- // 页表有空位,只需要开辟一个新的 PTE (Level 2)
- if (l2pt && !l2pt->entry[l2_index]) {
- l2pt->entry[l2_index] = NEW_L2_ENTRY(tattr, pa);
- return (void*)V_ADDR(l1_index, l2_index, PG_OFFSET(va));
- }
- l2_index++;
- }
-
- // 页目录与所有页表已满!
- if (l1_index > PG_MAX_ENTRIES) {
- return NULL;
- }
-
- if (!__vmm_map_internal(l1_index, l2_index, (uintptr_t)pa, tattr, false)) {
- return NULL;
- }
-
- return (void*)V_ADDR(l1_index, l2_index, PG_OFFSET(va));
-}
-
-void*
-vmm_fmap_page(void* va, void* pa, pt_attr tattr)
-{
- if (!pa || !va) {
- return NULL;
- }
-
- assert(((uintptr_t)va & 0xFFFU) == 0) assert(((uintptr_t)pa & 0xFFFU) == 0);