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 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 } 143