1 /* 2 * Helper routines for building identity mapping page tables. This is 3 * included by both the compressed kernel and the regular kernel. 4 */ 5 6 static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page, 7 unsigned long addr, unsigned long end) 8 { 9 addr &= PMD_MASK; 10 for (; addr < end; addr += PMD_SIZE) { 11 pmd_t *pmd = pmd_page + pmd_index(addr); 12 13 if (pmd_present(*pmd)) 14 continue; 15 16 set_pmd(pmd, __pmd((addr - info->offset) | info->pmd_flag)); 17 } 18 } 19 20 static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page, 21 unsigned long addr, unsigned long end) 22 { 23 unsigned long next; 24 25 for (; addr < end; addr = next) { 26 pud_t *pud = pud_page + pud_index(addr); 27 pmd_t *pmd; 28 29 next = (addr & PUD_MASK) + PUD_SIZE; 30 if (next > end) 31 next = end; 32 33 if (pud_present(*pud)) { 34 pmd = pmd_offset(pud, 0); 35 ident_pmd_init(info, pmd, addr, next); 36 continue; 37 } 38 pmd = (pmd_t *)info->alloc_pgt_page(info->context); 39 if (!pmd) 40 return -ENOMEM; 41 ident_pmd_init(info, pmd, addr, next); 42 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE)); 43 } 44 45 return 0; 46 } 47 48 int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page, 49 unsigned long pstart, unsigned long pend) 50 { 51 unsigned long addr = pstart + info->offset; 52 unsigned long end = pend + info->offset; 53 unsigned long next; 54 int result; 55 56 for (; addr < end; addr = next) { 57 pgd_t *pgd = pgd_page + pgd_index(addr); 58 pud_t *pud; 59 60 next = (addr & PGDIR_MASK) + PGDIR_SIZE; 61 if (next > end) 62 next = end; 63 64 if (pgd_present(*pgd)) { 65 pud = pud_offset(pgd, 0); 66 result = ident_pud_init(info, pud, addr, next); 67 if (result) 68 return result; 69 continue; 70 } 71 72 pud = (pud_t *)info->alloc_pgt_page(info->context); 73 if (!pud) 74 return -ENOMEM; 75 result = ident_pud_init(info, pud, addr, next); 76 if (result) 77 return result; 78 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE)); 79 } 80 81 return 0; 82 } 83