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  */
pfn_is_nosave(unsigned long pfn)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  */
compute_e820_crc32(struct e820_table * table)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  */
arch_hibernation_header_save(void * addr,unsigned int max_size)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  */
arch_hibernation_header_restore(void * addr)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 
relocate_restore_code(void)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_large(*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_large(*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_large(*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 
arch_resume_nosmt(void)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