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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 | // SPDX-License-Identifier: GPL-2.0 /* * Helper routines for building identity mapping page tables. This is * included by both the compressed kernel and the regular kernel. */ static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page, unsigned long addr, unsigned long end) { addr &= PMD_MASK; for (; addr < end; addr += PMD_SIZE) { pmd_t *pmd = pmd_page + pmd_index(addr); if (pmd_present(*pmd)) continue; set_pmd(pmd, __pmd((addr - info->offset) | info->page_flag)); } } static int ident_pud_init(struct x86_mapping_info *info, pud_t *pud_page, unsigned long addr, unsigned long end) { unsigned long next; for (; addr < end; addr = next) { pud_t *pud = pud_page + pud_index(addr); pmd_t *pmd; next = (addr & PUD_MASK) + PUD_SIZE; if (next > end) next = end; if (info->direct_gbpages) { pud_t pudval; if (pud_present(*pud)) continue; addr &= PUD_MASK; pudval = __pud((addr - info->offset) | info->page_flag); set_pud(pud, pudval); continue; } if (pud_present(*pud)) { pmd = pmd_offset(pud, 0); ident_pmd_init(info, pmd, addr, next); continue; } pmd = (pmd_t *)info->alloc_pgt_page(info->context); if (!pmd) return -ENOMEM; ident_pmd_init(info, pmd, addr, next); set_pud(pud, __pud(__pa(pmd) | info->kernpg_flag)); } return 0; } static int ident_p4d_init(struct x86_mapping_info *info, p4d_t *p4d_page, unsigned long addr, unsigned long end) { unsigned long next; int result; for (; addr < end; addr = next) { p4d_t *p4d = p4d_page + p4d_index(addr); pud_t *pud; next = (addr & P4D_MASK) + P4D_SIZE; if (next > end) next = end; if (p4d_present(*p4d)) { pud = pud_offset(p4d, 0); result = ident_pud_init(info, pud, addr, next); if (result) return result; continue; } pud = (pud_t *)info->alloc_pgt_page(info->context); if (!pud) return -ENOMEM; result = ident_pud_init(info, pud, addr, next); if (result) return result; set_p4d(p4d, __p4d(__pa(pud) | info->kernpg_flag)); } return 0; } int kernel_ident_mapping_init(struct x86_mapping_info *info, pgd_t *pgd_page, unsigned long pstart, unsigned long pend) { unsigned long addr = pstart + info->offset; unsigned long end = pend + info->offset; unsigned long next; int result; /* Set the default pagetable flags if not supplied */ if (!info->kernpg_flag) info->kernpg_flag = _KERNPG_TABLE; /* Filter out unsupported __PAGE_KERNEL_* bits: */ info->kernpg_flag &= __default_kernel_pte_mask; for (; addr < end; addr = next) { pgd_t *pgd = pgd_page + pgd_index(addr); p4d_t *p4d; next = (addr & PGDIR_MASK) + PGDIR_SIZE; if (next > end) next = end; if (pgd_present(*pgd)) { p4d = p4d_offset(pgd, 0); result = ident_p4d_init(info, p4d, addr, next); if (result) return result; continue; } p4d = (p4d_t *)info->alloc_pgt_page(info->context); if (!p4d) return -ENOMEM; result = ident_p4d_init(info, p4d, addr, next); if (result) return result; if (pgtable_l5_enabled()) { set_pgd(pgd, __pgd(__pa(p4d) | info->kernpg_flag)); } else { /* * With p4d folded, pgd is equal to p4d. * The pgd entry has to point to the pud page table in this case. */ pud_t *pud = pud_offset(p4d, 0); set_pgd(pgd, __pgd(__pa(pud) | info->kernpg_flag)); } } return 0; } |