1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Hibernation support for x86
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 #include <linux/gfp.h>
10 #include <linux/smp.h>
11 #include <linux/suspend.h>
12 #include <linux/scatterlist.h>
13 #include <linux/kdebug.h>
14 #include <linux/cpu.h>
15 #include <linux/pgtable.h>
16 #include <linux/types.h>
17 #include <linux/crc32.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 /*
29 * Address to jump to in the last phase of restore in order to get to the image
30 * kernel's text (this value is passed in the image header).
31 */
32 unsigned long restore_jump_address __visible;
33 unsigned long jump_address_phys;
34
35 /*
36 * Value of the cr3 register from before the hibernation (this value is passed
37 * in the image header).
38 */
39 unsigned long restore_cr3 __visible;
40 unsigned long temp_pgt __visible;
41 unsigned long relocated_restore_code __visible;
42
43 /**
44 * pfn_is_nosave - check if given pfn is in the 'nosave' section
45 */
46 int pfn_is_nosave(unsigned long pfn)
47 {
48 unsigned long nosave_begin_pfn;
49 unsigned long nosave_end_pfn;
50
51 nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
52 nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
53
54 return pfn >= nosave_begin_pfn && pfn < nosave_end_pfn;
55 }
56
57 struct restore_data_record {
58 unsigned long jump_address;
59 unsigned long jump_address_phys;
60 unsigned long cr3;
61 unsigned long magic;
62 unsigned long e820_checksum;
63 };
64
65 /**
66 * compute_e820_crc32 - calculate crc32 of a given e820 table
67 *
68 * @table: the e820 table to be calculated
69 *
70 * Return: the resulting checksum
71 */
72 static inline u32 compute_e820_crc32(struct e820_table *table)
73 {
74 int size = offsetof(struct e820_table, entries) +
75 sizeof(struct e820_entry) * table->nr_entries;
76
77 return ~crc32_le(~0, (unsigned char const *)table, size);
78 }
79
80 #ifdef CONFIG_X86_64
81 #define RESTORE_MAGIC 0x23456789ABCDEF02UL
82 #else
83 #define RESTORE_MAGIC 0x12345679UL
84 #endif
85
86 /**
87 * arch_hibernation_header_save - populate the architecture specific part
88 * of a hibernation image header
89 * @addr: address to save the data at
90 */
91 int arch_hibernation_header_save(void *addr, unsigned int max_size)
92 {
93 struct restore_data_record *rdr = addr;
94
95 if (max_size < sizeof(struct restore_data_record))
96 return -EOVERFLOW;
97 rdr->magic = RESTORE_MAGIC;
98 rdr->jump_address = (unsigned long)restore_registers;
99 rdr->jump_address_phys = __pa_symbol(restore_registers);
100
101 /*
102 * The restore code fixes up CR3 and CR4 in the following sequence:
103 *
104 * [in hibernation asm]
105 * 1. CR3 <= temporary page tables
106 * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
107 * 3. CR3 <= rdr->cr3
108 * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
109 * [in restore_processor_state()]
110 * 5. CR4 <= saved CR4
111 * 6. CR3 <= saved CR3
112 *
113 * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
114 * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
115 * rdr->cr3 needs to point to valid page tables but must not
116 * have any of the PCID bits set.
117 */
118 rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
119
120 rdr->e820_checksum = compute_e820_crc32(e820_table_firmware);
121 return 0;
122 }
123
124 /**
125 * arch_hibernation_header_restore - read the architecture specific data
126 * from the hibernation image header
127 * @addr: address to read the data from
128 */
129 int arch_hibernation_header_restore(void *addr)
130 {
131 struct restore_data_record *rdr = addr;
132
133 if (rdr->magic != RESTORE_MAGIC) {
134 pr_crit("Unrecognized hibernate image header format!\n");
135 return -EINVAL;
136 }
137
138 restore_jump_address = rdr->jump_address;
139 jump_address_phys = rdr->jump_address_phys;
140 restore_cr3 = rdr->cr3;
141
142 if (rdr->e820_checksum != compute_e820_crc32(e820_table_firmware)) {
143 pr_crit("Hibernate inconsistent memory map detected!\n");
144 return -ENODEV;
145 }
146
147 return 0;
148 }
149
150 int relocate_restore_code(void)
151 {
152 pgd_t *pgd;
153 p4d_t *p4d;
154 pud_t *pud;
155 pmd_t *pmd;
156 pte_t *pte;
157
158 relocated_restore_code = get_safe_page(GFP_ATOMIC);
159 if (!relocated_restore_code)
160 return -ENOMEM;
161
162 __memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
163
164 /* Make the page containing the relocated code executable */
165 pgd = (pgd_t *)__va(read_cr3_pa()) +
166 pgd_index(relocated_restore_code);
167 p4d = p4d_offset(pgd, relocated_restore_code);
168 if (p4d_leaf(*p4d)) {
169 set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
170 goto out;
171 }
172 pud = pud_offset(p4d, relocated_restore_code);
173 if (pud_leaf(*pud)) {
174 set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
175 goto out;
176 }
177 pmd = pmd_offset(pud, relocated_restore_code);
178 if (pmd_leaf(*pmd)) {
179 set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
180 goto out;
181 }
182 pte = pte_offset_kernel(pmd, relocated_restore_code);
183 set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
184 out:
185 __flush_tlb_all();
186 return 0;
187 }
188
189 int arch_resume_nosmt(void)
190 {
191 int ret = 0;
192 /*
193 * We reached this while coming out of hibernation. This means
194 * that SMT siblings are sleeping in hlt, as mwait is not safe
195 * against control transition during resume (see comment in
196 * hibernate_resume_nonboot_cpu_disable()).
197 *
198 * If the resumed kernel has SMT disabled, we have to take all the
199 * SMT siblings out of hlt, and offline them again so that they
200 * end up in mwait proper.
201 *
202 * Called with hotplug disabled.
203 */
204 cpu_hotplug_enable();
205 if (cpu_smt_control == CPU_SMT_DISABLED ||
206 cpu_smt_control == CPU_SMT_FORCE_DISABLED) {
207 enum cpuhp_smt_control old = cpu_smt_control;
208
209 ret = cpuhp_smt_enable();
210 if (ret)
211 goto out;
212 ret = cpuhp_smt_disable(old);
213 if (ret)
214 goto out;
215 }
216 out:
217 cpu_hotplug_disable();
218 return ret;
219 }
220
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