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: &info, pgd_page: pgd, pstart: mstart, pend: 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