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