| /* |
| * Hibernation support specific for i386 - temporary page tables |
| * |
| * Distribute under GPLv2 |
| * |
| * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl> |
| */ |
| |
| #include <linux/gfp.h> |
| #include <linux/suspend.h> |
| #include <linux/bootmem.h> |
| |
| #include <asm/page.h> |
| #include <asm/pgtable.h> |
| #include <asm/mmzone.h> |
| #include <asm/sections.h> |
| |
| /* Defined in hibernate_asm_32.S */ |
| extern int restore_image(void); |
| |
| /* Pointer to the temporary resume page tables */ |
| pgd_t *resume_pg_dir; |
| |
| /* The following three functions are based on the analogous code in |
| * arch/x86/mm/init_32.c |
| */ |
| |
| /* |
| * Create a middle page table on a resume-safe page and put a pointer to it in |
| * the given global directory entry. This only returns the gd entry |
| * in non-PAE compilation mode, since the middle layer is folded. |
| */ |
| static pmd_t *resume_one_md_table_init(pgd_t *pgd) |
| { |
| p4d_t *p4d; |
| pud_t *pud; |
| pmd_t *pmd_table; |
| |
| #ifdef CONFIG_X86_PAE |
| pmd_table = (pmd_t *)get_safe_page(GFP_ATOMIC); |
| if (!pmd_table) |
| return NULL; |
| |
| set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT)); |
| p4d = p4d_offset(pgd, 0); |
| pud = pud_offset(p4d, 0); |
| |
| BUG_ON(pmd_table != pmd_offset(pud, 0)); |
| #else |
| p4d = p4d_offset(pgd, 0); |
| pud = pud_offset(p4d, 0); |
| pmd_table = pmd_offset(pud, 0); |
| #endif |
| |
| return pmd_table; |
| } |
| |
| /* |
| * Create a page table on a resume-safe page and place a pointer to it in |
| * a middle page directory entry. |
| */ |
| static pte_t *resume_one_page_table_init(pmd_t *pmd) |
| { |
| if (pmd_none(*pmd)) { |
| pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC); |
| if (!page_table) |
| return NULL; |
| |
| set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE)); |
| |
| BUG_ON(page_table != pte_offset_kernel(pmd, 0)); |
| |
| return page_table; |
| } |
| |
| return pte_offset_kernel(pmd, 0); |
| } |
| |
| /* |
| * This maps the physical memory to kernel virtual address space, a total |
| * of max_low_pfn pages, by creating page tables starting from address |
| * PAGE_OFFSET. The page tables are allocated out of resume-safe pages. |
| */ |
| static int resume_physical_mapping_init(pgd_t *pgd_base) |
| { |
| unsigned long pfn; |
| pgd_t *pgd; |
| pmd_t *pmd; |
| pte_t *pte; |
| int pgd_idx, pmd_idx; |
| |
| pgd_idx = pgd_index(PAGE_OFFSET); |
| pgd = pgd_base + pgd_idx; |
| pfn = 0; |
| |
| for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) { |
| pmd = resume_one_md_table_init(pgd); |
| if (!pmd) |
| return -ENOMEM; |
| |
| if (pfn >= max_low_pfn) |
| continue; |
| |
| for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) { |
| if (pfn >= max_low_pfn) |
| break; |
| |
| /* Map with big pages if possible, otherwise create |
| * normal page tables. |
| * NOTE: We can mark everything as executable here |
| */ |
| if (boot_cpu_has(X86_FEATURE_PSE)) { |
| set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC)); |
| pfn += PTRS_PER_PTE; |
| } else { |
| pte_t *max_pte; |
| |
| pte = resume_one_page_table_init(pmd); |
| if (!pte) |
| return -ENOMEM; |
| |
| max_pte = pte + PTRS_PER_PTE; |
| for (; pte < max_pte; pte++, pfn++) { |
| if (pfn >= max_low_pfn) |
| break; |
| |
| set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC)); |
| } |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| static inline void resume_init_first_level_page_table(pgd_t *pg_dir) |
| { |
| #ifdef CONFIG_X86_PAE |
| int i; |
| |
| /* Init entries of the first-level page table to the zero page */ |
| for (i = 0; i < PTRS_PER_PGD; i++) |
| set_pgd(pg_dir + i, |
| __pgd(__pa(empty_zero_page) | _PAGE_PRESENT)); |
| #endif |
| } |
| |
| asmlinkage int swsusp_arch_resume(void) |
| { |
| int error; |
| |
| resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC); |
| if (!resume_pg_dir) |
| return -ENOMEM; |
| |
| resume_init_first_level_page_table(resume_pg_dir); |
| error = resume_physical_mapping_init(resume_pg_dir); |
| if (error) |
| return error; |
| |
| /* We have got enough memory and from now on we cannot recover */ |
| restore_image(); |
| return 0; |
| } |
| |
| /* |
| * pfn_is_nosave - check if given pfn is in the 'nosave' section |
| */ |
| |
| int pfn_is_nosave(unsigned long pfn) |
| { |
| unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT; |
| unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT; |
| return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn); |
| } |