| 86,51 → 86,3 |
|---|
| |
| paging_on(); |
| } |
| |
| /* |
| * Besides mapping pages to frames, this function also sets the present bit of |
| * the page's specifier in both page directory and respective page table. If |
| * the page table for this page has not been allocated so far, it will take |
| * care of it and allocate the necessary frame. |
| * |
| * PAGE_CACHEABLE flag: when set, it turns caches for that page on |
| * PAGE_NOT_PRESENT flag: when set, it marks the page not present |
| * PAGE_USER flag: when set, the page is accessible from userspace |
| * |
| * When the root parameter is non-zero, it is used as the page directory address. |
| * Otherwise, the page directory address is read from CPU. |
| */ |
| void map_page_to_frame(__address page, __address frame, int flags, __address root) |
| { |
| struct page_specifier *pd, *pt; |
| __address dba, newpt; |
| int pde, pte; |
| |
| if (root) dba = root; |
| else dba = read_cr3(); |
| |
| pde = page >> 22; /* page directory entry */ |
| pte = (page >> 12) & 0x3ff; /* page table entry */ |
| |
| pd = (struct page_specifier *) PA2KA(dba); |
| |
| if (!pd[pde].present) { |
| /* |
| * There is currently no page table for this address. Allocate |
| * frame for the page table and clean it. |
| */ |
| newpt = frame_alloc(FRAME_KA); |
| pd[pde].frame_address = KA2PA(newpt) >> 12; |
| memsetb(newpt, PAGE_SIZE, 0); |
| pd[pde].present = 1; |
| pd[pde].uaccessible = 1; |
| } |
| |
| pt = (struct page_specifier *) PA2KA((pd[pde].frame_address << 12)); |
| |
| pt[pte].frame_address = frame >> 12; |
| pt[pte].present = !(flags & PAGE_NOT_PRESENT); |
| pt[pte].page_cache_disable = !(flags & PAGE_CACHEABLE); |
| pt[pte].uaccessible = (flags & PAGE_USER) != 0; |
| pt[pte].writeable = (flags & PAGE_WRITE) != 0; |
| } |