diff options
Diffstat (limited to 'arch/x86/power/suspend.c')
| -rw-r--r-- | arch/x86/power/suspend.c | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/arch/x86/power/suspend.c b/arch/x86/power/suspend.c new file mode 100644 index 00000000000..a0020b913f3 --- /dev/null +++ b/arch/x86/power/suspend.c @@ -0,0 +1,172 @@ +/* + * Suspend support specific for i386 - temporary page tables + * + * Distribute under GPLv2 + * + * Copyright (c) 2006 Rafael J. Wysocki <rjw@sisk.pl> + */ + +#include <linux/suspend.h> +#include <linux/bootmem.h> + +#include <asm/system.h> +#include <asm/page.h> +#include <asm/pgtable.h> + +/* Defined in arch/i386/power/swsusp.S */ +extern int restore_image(void); + +/* References to section boundaries */ +extern const void __nosave_begin, __nosave_end; + +/* Pointer to the temporary resume page tables */ +pgd_t *resume_pg_dir; + +/* The following three functions are based on the analogous code in + * arch/i386/mm/init.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) +{ + 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)); + pud = pud_offset(pgd, 0); + + BUG_ON(pmd_table != pmd_offset(pud, 0)); +#else + pud = pud_offset(pgd, 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 (cpu_has_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 +} + +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); +} |