// 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; 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); ident_pud_init(info, pud, addr, next); continue; } pud = (pud_t *)info->alloc_pgt_page(info->context); if (!pud) return -ENOMEM; ident_pud_init(info, pud, addr, next); 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; 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 (IS_ENABLED(CONFIG_X86_5LEVEL)) { 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; }