arch/x86/power/hibernate_64.c

   1 /*
   2  * Hibernation support for x86-64
   3  *
   4  * Distribute under GPLv2
   5  *
   6  * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
   7  * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
   8  * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
   9  */
  10
  11 #include <linux/gfp.h>
  12 #include <linux/smp.h>
  13 #include <linux/suspend.h>
  14 #include <linux/scatterlist.h>
  15 #include <linux/kdebug.h>
  16
  17 #include <crypto/hash.h>
  18
  19 #include <asm/e820/api.h>
  20 #include <asm/init.h>
  21 #include <asm/proto.h>
  22 #include <asm/page.h>
  23 #include <asm/pgtable.h>
  24 #include <asm/mtrr.h>
  25 #include <asm/sections.h>
  26 #include <asm/suspend.h>
  27 #include <asm/tlbflush.h>
  28
  29 static int set_up_temporary_text_mapping(pgd_t *pgd)
  30 {
  31         pmd_t *pmd;
  32         pud_t *pud;
  33         p4d_t *p4d = NULL;
  34         pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
  35         pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
  36
  37         /* Filter out unsupported __PAGE_KERNEL* bits: */
  38         pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
  39         pgprot_val(pgtable_prot)  &= __default_kernel_pte_mask;
  40
  41         /*
  42          * The new mapping only has to cover the page containing the image
  43          * kernel's entry point (jump_address_phys), because the switch over to
  44          * it is carried out by relocated code running from a page allocated
  45          * specifically for this purpose and covered by the identity mapping, so
  46          * the temporary kernel text mapping is only needed for the final jump.
  47          * Moreover, in that mapping the virtual address of the image kernel's
  48          * entry point must be the same as its virtual address in the image
  49          * kernel (restore_jump_address), so the image kernel's
  50          * restore_registers() code doesn't find itself in a different area of
  51          * the virtual address space after switching over to the original page
  52          * tables used by the image kernel.
  53          */
  54
  55         if (pgtable_l5_enabled()) {
  56                 p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
  57                 if (!p4d)
  58                         return -ENOMEM;
  59         }
  60
  61         pud = (pud_t *)get_safe_page(GFP_ATOMIC);
  62         if (!pud)
  63                 return -ENOMEM;
  64
  65         pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
  66         if (!pmd)
  67                 return -ENOMEM;
  68
  69         set_pmd(pmd + pmd_index(restore_jump_address),
  70                 __pmd((jump_address_phys & PMD_MASK) | pgprot_val(pmd_text_prot)));
  71         set_pud(pud + pud_index(restore_jump_address),
  72                 __pud(__pa(pmd) | pgprot_val(pgtable_prot)));
  73         if (p4d) {
  74                 p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
  75                 pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));
  76
  77                 set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
  78                 set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
  79         } else {
  80                 /* No p4d for 4-level paging: point the pgd to the pud page table */
  81                 pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
  82                 set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
  83         }
  84
  85         return 0;
  86 }
  87
  88 static void *alloc_pgt_page(void *context)
  89 {
  90         return (void *)get_safe_page(GFP_ATOMIC);
  91 }
  92
  93 static int set_up_temporary_mappings(void)
  94 {
  95         struct x86_mapping_info info = {
  96                 .alloc_pgt_page = alloc_pgt_page,
  97                 .page_flag      = __PAGE_KERNEL_LARGE_EXEC,
  98                 .offset         = __PAGE_OFFSET,
  99         };
 100         unsigned long mstart, mend;
 101         pgd_t *pgd;
 102         int result;
 103         int i;
 104
 105         pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
 106         if (!pgd)
 107                 return -ENOMEM;
 108
 109         /* Prepare a temporary mapping for the kernel text */
 110         result = set_up_temporary_text_mapping(pgd);
 111         if (result)
 112                 return result;
 113
 114         /* Set up the direct mapping from scratch */
 115         for (i = 0; i < nr_pfn_mapped; i++) {
 116                 mstart = pfn_mapped[i].start << PAGE_SHIFT;
 117                 mend   = pfn_mapped[i].end << PAGE_SHIFT;
 118
 119                 result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
 120                 if (result)
 121                         return result;
 122         }
 123
 124         temp_pgt = __pa(pgd);
 125         return 0;
 126 }
 127
 128 asmlinkage int swsusp_arch_resume(void)
 129 {
 130         int error;
 131
 132         /* We have got enough memory and from now on we cannot recover */
 133         error = set_up_temporary_mappings();
 134         if (error)
 135                 return error;
 136
 137         error = relocate_restore_code();
 138         if (error)
 139                 return error;
 140
 141         restore_image();
 142         return 0;
 143 }