1 // SPDX-License-Identifier: GPL-2.0-only
3 * Hibernation support specific for i386 - temporary page tables
5 * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl>
9 #include <linux/suspend.h>
10 #include <linux/memblock.h>
13 #include <asm/pgtable.h>
14 #include <asm/mmzone.h>
15 #include <asm/sections.h>
16 #include <asm/suspend.h>
18 /* Pointer to the temporary resume page tables */
21 /* The following three functions are based on the analogous code in
22 * arch/x86/mm/init_32.c
26 * Create a middle page table on a resume-safe page and put a pointer to it in
27 * the given global directory entry. This only returns the gd entry
28 * in non-PAE compilation mode, since the middle layer is folded.
30 static pmd_t *resume_one_md_table_init(pgd_t *pgd)
37 pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC);
41 set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
42 p4d = p4d_offset(pgd, 0);
43 pud = pud_offset(p4d, 0);
45 BUG_ON(pmd_table != pmd_offset(pud, 0));
47 p4d = p4d_offset(pgd, 0);
48 pud = pud_offset(p4d, 0);
49 pmd_table = pmd_offset(pud, 0);
56 * Create a page table on a resume-safe page and place a pointer to it in
57 * a middle page directory entry.
59 static pte_t *resume_one_page_table_init(pmd_t *pmd)
62 pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
66 set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
68 BUG_ON(page_table != pte_offset_kernel(pmd, 0));
73 return pte_offset_kernel(pmd, 0);
77 * This maps the physical memory to kernel virtual address space, a total
78 * of max_low_pfn pages, by creating page tables starting from address
79 * PAGE_OFFSET. The page tables are allocated out of resume-safe pages.
81 static int resume_physical_mapping_init(pgd_t *pgd_base)
89 pgd_idx = pgd_index(PAGE_OFFSET);
90 pgd = pgd_base + pgd_idx;
93 for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
94 pmd = resume_one_md_table_init(pgd);
98 if (pfn >= max_low_pfn)
101 for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
102 if (pfn >= max_low_pfn)
105 /* Map with big pages if possible, otherwise create
106 * normal page tables.
107 * NOTE: We can mark everything as executable here
109 if (boot_cpu_has(X86_FEATURE_PSE)) {
110 set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
115 pte = resume_one_page_table_init(pmd);
119 max_pte = pte + PTRS_PER_PTE;
120 for (; pte < max_pte; pte++, pfn++) {
121 if (pfn >= max_low_pfn)
124 set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
133 static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
135 #ifdef CONFIG_X86_PAE
138 /* Init entries of the first-level page table to the zero page */
139 for (i = 0; i < PTRS_PER_PGD; i++)
141 __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
145 static int set_up_temporary_text_mapping(pgd_t *pgd_base)
151 pgd = pgd_base + pgd_index(restore_jump_address);
153 pmd = resume_one_md_table_init(pgd);
157 if (boot_cpu_has(X86_FEATURE_PSE)) {
158 set_pmd(pmd + pmd_index(restore_jump_address),
159 __pmd((jump_address_phys & PMD_MASK) | pgprot_val(PAGE_KERNEL_LARGE_EXEC)));
161 pte = resume_one_page_table_init(pmd);
164 set_pte(pte + pte_index(restore_jump_address),
165 __pte((jump_address_phys & PAGE_MASK) | pgprot_val(PAGE_KERNEL_EXEC)));
171 asmlinkage int swsusp_arch_resume(void)
175 resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
179 resume_init_first_level_page_table(resume_pg_dir);
181 error = set_up_temporary_text_mapping(resume_pg_dir);
185 error = resume_physical_mapping_init(resume_pg_dir);
189 temp_pgt = __pa(resume_pg_dir);
191 error = relocate_restore_code();
195 /* We have got enough memory and from now on we cannot recover */