LXR linux/arch/x86/power/hibernate

   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#include <linux/pgtable.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/mtrr.h>
  24#include <asm/sections.h>
  25#include <asm/suspend.h>
  26#include <asm/tlbflush.h>
  27
  28static 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
  87static void *alloc_pgt_page(void *context)
  88{
  89        return (void *)get_safe_page(GFP_ATOMIC);
  90}
  91
  92static 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
 127asmlinkage 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}
 143