| 103,6 → 103,8 |
|---|
| * TLB shootdown should follow in order to make effects of |
| * this call visible. |
| * |
| * Empty page tables except PTL0 are freed. |
| * |
| * The address space must be locked and interrupts must be disabled. |
| * |
| * @param as Address space to wich page belongs. |
| 111,7 → 113,13 |
|---|
| void pt_mapping_remove(as_t *as, __address page) |
| { |
| pte_t *ptl0, *ptl1, *ptl2, *ptl3; |
| bool empty = true; |
| int i; |
| |
| /* |
| * First, remove the mapping, if it exists. |
| */ |
| |
| ptl0 = (pte_t *) PA2KA((__address) as->page_table); |
| |
| if (GET_PTL1_FLAGS(ptl0, PTL0_INDEX(page)) & PAGE_NOT_PRESENT) |
| 131,6 → 139,86 |
|---|
| |
| /* Destroy the mapping. Setting to PAGE_NOT_PRESENT is not sufficient. */ |
| memsetb((__address) &ptl3[PTL3_INDEX(page)], sizeof(pte_t), 0); |
| |
| /* |
| * Second, free all empty tables along the way from PTL3 down to PTL0. |
| */ |
| |
| /* check PTL3 */ |
| for (i = 0; i < PTL3_ENTRIES; i++) { |
| if (PTE_VALID(&ptl3[i])) { |
| empty = false; |
| break; |
| } |
| } |
| if (empty) { |
| /* |
| * PTL3 is empty. |
| * Release the frame and remove PTL3 pointer from preceding table. |
| */ |
| frame_free(ADDR2PFN(KA2PA((__address) ptl3))); |
| if (PTL2_ENTRIES) |
| memsetb((__address) &ptl2[PTL2_INDEX(page)], sizeof(pte_t), 0); |
| else if (PTL1_ENTRIES) |
| memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0); |
| else |
| memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0); |
| } else { |
| /* |
| * PTL3 is not empty. |
| * Therefore, there must be a path from PTL0 to PTL3 and |
| * thus nothing to free in higher levels. |
| */ |
| return; |
| } |
| |
| /* check PTL2, empty is still true */ |
| if (PTL2_ENTRIES) { |
| for (i = 0; i < PTL2_ENTRIES; i++) { |
| if (PTE_VALID(&ptl2[i])) { |
| empty = false; |
| break; |
| } |
| } |
| if (empty) { |
| /* |
| * PTL2 is empty. |
| * Release the frame and remove PTL2 pointer from preceding table. |
| */ |
| frame_free(ADDR2PFN(KA2PA((__address) ptl2))); |
| if (PTL1_ENTRIES) |
| memsetb((__address) &ptl1[PTL1_INDEX(page)], sizeof(pte_t), 0); |
| else |
| memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0); |
| } |
| else { |
| /* |
| * PTL2 is not empty. |
| * Therefore, there must be a path from PTL0 to PTL2 and |
| * thus nothing to free in higher levels. |
| */ |
| return; |
| } |
| } |
| |
| /* check PTL1, empty is still true */ |
| if (PTL1_ENTRIES) { |
| for (i = 0; i < PTL1_ENTRIES; i++) { |
| if (PTE_VALID(&ptl1[i])) { |
| empty = false; |
| break; |
| } |
| } |
| if (empty) { |
| /* |
| * PTL1 is empty. |
| * Release the frame and remove PTL1 pointer from preceding table. |
| */ |
| frame_free(ADDR2PFN(KA2PA((__address) ptl1))); |
| memsetb((__address) &ptl0[PTL0_INDEX(page)], sizeof(pte_t), 0); |
| } |
| } |
| |
| } |
| |
| /** Find mapping for virtual page in hierarchical page tables. |