cregit-Linux how code gets into the kernel

Release 4.7 arch/x86/power/hibernate_64.c

Directory: arch/x86/power
/*
 * Hibernation support for x86-64
 *
 * Distribute under GPLv2
 *
 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
 * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
 */

#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/suspend.h>

#include <asm/init.h>
#include <asm/proto.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/mtrr.h>
#include <asm/sections.h>
#include <asm/suspend.h>
#include <asm/tlbflush.h>

/* Defined in hibernate_asm_64.S */
extern asmlinkage __visible int restore_image(void);

/*
 * Address to jump to in the last phase of restore in order to get to the image
 * kernel's text (this value is passed in the image header).
 */

unsigned long restore_jump_address __visible;

unsigned long jump_address_phys;

/*
 * Value of the cr3 register from before the hibernation (this value is passed
 * in the image header).
 */

unsigned long restore_cr3 __visible;


pgd_t *temp_level4_pgt __visible;


unsigned long relocated_restore_code __visible;


static int set_up_temporary_text_mapping(void) { pmd_t *pmd; pud_t *pud; /* * The new mapping only has to cover the page containing the image * kernel's entry point (jump_address_phys), because the switch over to * it is carried out by relocated code running from a page allocated * specifically for this purpose and covered by the identity mapping, so * the temporary kernel text mapping is only needed for the final jump. * Moreover, in that mapping the virtual address of the image kernel's * entry point must be the same as its virtual address in the image * kernel (restore_jump_address), so the image kernel's * restore_registers() code doesn't find itself in a different area of * the virtual address space after switching over to the original page * tables used by the image kernel. */ pud = (pud_t *)get_safe_page(GFP_ATOMIC); if (!pud) return -ENOMEM; pmd = (pmd_t *)get_safe_page(GFP_ATOMIC); if (!pmd) return -ENOMEM; set_pmd(pmd + pmd_index(restore_jump_address), __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC)); set_pud(pud + pud_index(restore_jump_address), __pud(__pa(pmd) | _KERNPG_TABLE)); set_pgd(temp_level4_pgt + pgd_index(restore_jump_address), __pgd(__pa(pud) | _KERNPG_TABLE)); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki121100.00%1100.00%
Total121100.00%1100.00%


static void *alloc_pgt_page(void *context) { return (void *)get_safe_page(GFP_ATOMIC); }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki1466.67%266.67%
yinghai luyinghai lu733.33%133.33%
Total21100.00%3100.00%


static int set_up_temporary_mappings(void) { struct x86_mapping_info info = { .alloc_pgt_page = alloc_pgt_page, .pmd_flag = __PAGE_KERNEL_LARGE_EXEC, .kernel_mapping = true, }; unsigned long mstart, mend; int result; int i; temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC); if (!temp_level4_pgt) return -ENOMEM; /* Prepare a temporary mapping for the kernel text */ result = set_up_temporary_text_mapping(); if (result) return result; /* Set up the direct mapping from scratch */ for (i = 0; i < nr_pfn_mapped; i++) { mstart = pfn_mapped[i].start << PAGE_SHIFT; mend = pfn_mapped[i].end << PAGE_SHIFT; result = kernel_ident_mapping_init(&info, temp_level4_pgt, mstart, mend); if (result) return result; } return 0; }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki7152.21%360.00%
yinghai luyinghai lu6346.32%120.00%
andrew mortonandrew morton21.47%120.00%
Total136100.00%5100.00%


static int relocate_restore_code(void) { pgd_t *pgd; pud_t *pud; relocated_restore_code = get_safe_page(GFP_ATOMIC); if (!relocated_restore_code) return -ENOMEM; memcpy((void *)relocated_restore_code, &core_restore_code, PAGE_SIZE); /* Make the page containing the relocated code executable */ pgd = (pgd_t *)__va(read_cr3()) + pgd_index(relocated_restore_code); pud = pud_offset(pgd, relocated_restore_code); if (pud_large(*pud)) { set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX)); } else { pmd_t *pmd = pmd_offset(pud, relocated_restore_code); if (pmd_large(*pmd)) { set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX)); } else { pte_t *pte = pte_offset_kernel(pmd, relocated_restore_code); set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX)); } } __flush_tlb_all(); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki178100.00%3100.00%
Total178100.00%3100.00%


int swsusp_arch_resume(void) { int error; /* We have got enough memory and from now on we cannot recover */ error = set_up_temporary_mappings(); if (error) return error; error = relocate_restore_code(); if (error) return error; restore_image(); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki41100.00%2100.00%
Total41100.00%2100.00%

/* * 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); }

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PersonTokensPropCommitsCommitProp
vivek goyalvivek goyal49100.00%1100.00%
Total49100.00%1100.00%

struct restore_data_record { unsigned long jump_address; unsigned long jump_address_phys; unsigned long cr3; unsigned long magic; }; #define RESTORE_MAGIC 0x123456789ABCDEF0UL /** * arch_hibernation_header_save - populate the architecture specific part * of a hibernation image header * @addr: address to save the data at */
int arch_hibernation_header_save(void *addr, unsigned int max_size) { struct restore_data_record *rdr = addr; if (max_size < sizeof(struct restore_data_record)) return -EOVERFLOW; rdr->jump_address = (unsigned long)&restore_registers; rdr->jump_address_phys = __pa_symbol(&restore_registers); rdr->cr3 = restore_cr3; rdr->magic = RESTORE_MAGIC; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki70100.00%3100.00%
Total70100.00%3100.00%

/** * arch_hibernation_header_restore - read the architecture specific data * from the hibernation image header * @addr: address to read the data from */
int arch_hibernation_header_restore(void *addr) { struct restore_data_record *rdr = addr; restore_jump_address = rdr->jump_address; jump_address_phys = rdr->jump_address_phys; restore_cr3 = rdr->cr3; return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL; }

Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki48100.00%3100.00%
Total48100.00%3100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
rafael j. wysockirafael j. wysocki60979.92%631.58%
yinghai luyinghai lu739.58%15.26%
vivek goyalvivek goyal506.56%15.26%
andi kleenandi kleen141.84%421.05%
geert uytterhoevengeert uytterhoeven30.39%15.26%
bernhard kaindlbernhard kaindl30.39%15.26%
tejun heotejun heo30.39%15.26%
magnus dammmagnus damm30.39%15.26%
andrew mortonandrew morton20.26%15.26%
al viroal viro10.13%15.26%
pavel machekpavel machek10.13%15.26%
Total762100.00%19100.00%
Directory: arch/x86/power
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