root/arch/x86/power/hibernate_64.c

DEFINITIONS

1. set_up_temporary_text_mapping
2. alloc_pgt_page
3. set_up_temporary_mappings
4. swsusp_arch_resume

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Hibernation support for x86-64
   4  *
   5  * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
   6  * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
   7  * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
   8  */
   9 
  10 #include <linux/gfp.h>
  11 #include <linux/smp.h>
  12 #include <linux/suspend.h>
  13 #include <linux/scatterlist.h>
  14 #include <linux/kdebug.h>
  15 
  16 #include <crypto/hash.h>
  17 
  18 #include <asm/e820/api.h>
  19 #include <asm/init.h>
  20 #include <asm/proto.h>
  21 #include <asm/page.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/mtrr.h>
  24 #include <asm/sections.h>
  25 #include <asm/suspend.h>
  26 #include <asm/tlbflush.h>
  27 
  28 static int set_up_temporary_text_mapping(pgd_t *pgd)
  29 {
  30         pmd_t *pmd;
  31         pud_t *pud;
  32         p4d_t *p4d = NULL;
  33         pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
  34         pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
  35 
  36         /* Filter out unsupported __PAGE_KERNEL* bits: */
  37         pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
  38         pgprot_val(pgtable_prot)  &= __default_kernel_pte_mask;
  39 
  40         /*
  41          * The new mapping only has to cover the page containing the image
  42          * kernel's entry point (jump_address_phys), because the switch over to
  43          * it is carried out by relocated code running from a page allocated
  44          * specifically for this purpose and covered by the identity mapping, so
  45          * the temporary kernel text mapping is only needed for the final jump.
  46          * Moreover, in that mapping the virtual address of the image kernel's
  47          * entry point must be the same as its virtual address in the image
  48          * kernel (restore_jump_address), so the image kernel's
  49          * restore_registers() code doesn't find itself in a different area of
  50          * the virtual address space after switching over to the original page
  51          * tables used by the image kernel.
  52          */
  53 
  54         if (pgtable_l5_enabled()) {
  55                 p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
  56                 if (!p4d)
  57                         return -ENOMEM;
  58         }
  59 
  60         pud = (pud_t *)get_safe_page(GFP_ATOMIC);
  61         if (!pud)
  62                 return -ENOMEM;
  63 
  64         pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
  65         if (!pmd)
  66                 return -ENOMEM;
  67 
  68         set_pmd(pmd + pmd_index(restore_jump_address),
  69                 __pmd((jump_address_phys & PMD_MASK) | pgprot_val(pmd_text_prot)));
  70         set_pud(pud + pud_index(restore_jump_address),
  71                 __pud(__pa(pmd) | pgprot_val(pgtable_prot)));
  72         if (p4d) {
  73                 p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
  74                 pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
  75 
  76                 set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
  77                 set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
  78         } else {
  79                 /* No p4d for 4-level paging: point the pgd to the pud page table */
  80                 pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
  81                 set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
  82         }
  83 
  84         return 0;
  85 }
  86 
  87 static void *alloc_pgt_page(void *context)
  88 {
  89         return (void *)get_safe_page(GFP_ATOMIC);
  90 }
  91 
  92 static int set_up_temporary_mappings(void)
  93 {
  94         struct x86_mapping_info info = {
  95                 .alloc_pgt_page = alloc_pgt_page,
  96                 .page_flag      = __PAGE_KERNEL_LARGE_EXEC,
  97                 .offset         = __PAGE_OFFSET,
  98         };
  99         unsigned long mstart, mend;
 100         pgd_t *pgd;
 101         int result;
 102         int i;
 103 
 104         pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
 105         if (!pgd)
 106                 return -ENOMEM;
 107 
 108         /* Prepare a temporary mapping for the kernel text */
 109         result = set_up_temporary_text_mapping(pgd);
 110         if (result)
 111                 return result;
 112 
 113         /* Set up the direct mapping from scratch */
 114         for (i = 0; i < nr_pfn_mapped; i++) {
 115                 mstart = pfn_mapped[i].start << PAGE_SHIFT;
 116                 mend   = pfn_mapped[i].end << PAGE_SHIFT;
 117 
 118                 result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
 119                 if (result)
 120                         return result;
 121         }
 122 
 123         temp_pgt = __pa(pgd);
 124         return 0;
 125 }
 126 
 127 asmlinkage int swsusp_arch_resume(void)
 128 {
 129         int error;
 130 
 131         /* We have got enough memory and from now on we cannot recover */
 132         error = set_up_temporary_mappings();
 133         if (error)
 134                 return error;
 135 
 136         error = relocate_restore_code();
 137         if (error)
 138                 return error;
 139 
 140         restore_image();
 141         return 0;
 142 }