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