From d88e7b3e35cff2c318042990d70828f64c3ae296 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 14 Jun 2024 12:59:02 +0300 Subject: x86/mm: Introduce kernel_ident_mapping_free() The helper complements kernel_ident_mapping_init(): it frees the identity mapping that was previously allocated. It will be used in the error path to free a partially allocated mapping or if the mapping is no longer needed. The caller provides a struct x86_mapping_info with the free_pgd_page() callback hooked up and the pgd_t to free. Signed-off-by: Kirill A. Shutemov Signed-off-by: Borislav Petkov (AMD) Acked-by: Kai Huang Tested-by: Tao Liu Link: https://lore.kernel.org/r/20240614095904.1345461-18-kirill.shutemov@linux.intel.com --- arch/x86/mm/ident_map.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 73 insertions(+) (limited to 'arch/x86/mm') diff --git a/arch/x86/mm/ident_map.c b/arch/x86/mm/ident_map.c index 968d7005f4a7..c45127265f2f 100644 --- a/arch/x86/mm/ident_map.c +++ b/arch/x86/mm/ident_map.c @@ -4,6 +4,79 @@ * included by both the compressed kernel and the regular kernel. */ +static void free_pte(struct x86_mapping_info *info, pmd_t *pmd) +{ + pte_t *pte = pte_offset_kernel(pmd, 0); + + info->free_pgt_page(pte, info->context); +} + +static void free_pmd(struct x86_mapping_info *info, pud_t *pud) +{ + pmd_t *pmd = pmd_offset(pud, 0); + int i; + + for (i = 0; i < PTRS_PER_PMD; i++) { + if (!pmd_present(pmd[i])) + continue; + + if (pmd_leaf(pmd[i])) + continue; + + free_pte(info, &pmd[i]); + } + + info->free_pgt_page(pmd, info->context); +} + +static void free_pud(struct x86_mapping_info *info, p4d_t *p4d) +{ + pud_t *pud = pud_offset(p4d, 0); + int i; + + for (i = 0; i < PTRS_PER_PUD; i++) { + if (!pud_present(pud[i])) + continue; + + if (pud_leaf(pud[i])) + continue; + + free_pmd(info, &pud[i]); + } + + info->free_pgt_page(pud, info->context); +} + +static void free_p4d(struct x86_mapping_info *info, pgd_t *pgd) +{ + p4d_t *p4d = p4d_offset(pgd, 0); + int i; + + for (i = 0; i < PTRS_PER_P4D; i++) { + if (!p4d_present(p4d[i])) + continue; + + free_pud(info, &p4d[i]); + } + + if (pgtable_l5_enabled()) + info->free_pgt_page(p4d, info->context); +} + +void kernel_ident_mapping_free(struct x86_mapping_info *info, pgd_t *pgd) +{ + int i; + + for (i = 0; i < PTRS_PER_PGD; i++) { + if (!pgd_present(pgd[i])) + continue; + + free_p4d(info, &pgd[i]); + } + + info->free_pgt_page(pgd, info->context); +} + static void ident_pmd_init(struct x86_mapping_info *info, pmd_t *pmd_page, unsigned long addr, unsigned long end) { -- cgit v1.2.3