cregit-Linux how code gets into the kernel

Release 4.14 arch/x86/power/hibernate_32.c

Directory: arch/x86/power
/*
 * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Rafael J. Wysocki10080.65%150.00%
Kirill A. Shutemov2419.35%150.00%
Total124100.00%2100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Rafael J. Wysocki80100.00%1100.00%
Total80100.00%1100.00%

/* * 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; }

Contributors

PersonTokensPropCommitsCommitProp
Rafael J. Wysocki19998.03%150.00%
Borislav Petkov41.97%150.00%
Total203100.00%2100.00%


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 }

Contributors

PersonTokensPropCommitsCommitProp
Rafael J. Wysocki50100.00%1100.00%
Total50100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Rafael J. Wysocki56100.00%1100.00%
Total56100.00%1100.00%

/* * 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); }

Contributors

PersonTokensPropCommitsCommitProp
Vivek Goyal49100.00%1100.00%
Total49100.00%1100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Rafael J. Wysocki51886.05%444.44%
Vivek Goyal508.31%111.11%
Kirill A. Shutemov243.99%111.11%
Borislav Petkov40.66%111.11%
Tejun Heo30.50%111.11%
Geert Uytterhoeven30.50%111.11%
Total602100.00%9100.00%
Directory: arch/x86/power
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