summaryrefslogtreecommitdiffstats
path: root/arch/x86/power/hibernate.c
blob: 5b81d19cd114c7d5d44a51545d3caf8fff241d1f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
// SPDX-License-Identifier: GPL-2.0
/*
 * Hibernation support for x86
 *
 * Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
 * Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
 * Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
 */
#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/suspend.h>
#include <linux/scatterlist.h>
#include <linux/kdebug.h>
#include <linux/cpu.h>
#include <linux/pgtable.h>
#include <linux/types.h>
#include <linux/crc32.h>

#include <asm/e820/api.h>
#include <asm/init.h>
#include <asm/proto.h>
#include <asm/page.h>
#include <asm/mtrr.h>
#include <asm/sections.h>
#include <asm/suspend.h>
#include <asm/tlbflush.h>

/*
 * Address to jump to in the last phase of restore in order to get to the image
 * kernel's text (this value is passed in the image header).
 */
unsigned long restore_jump_address __visible;
unsigned long jump_address_phys;

/*
 * Value of the cr3 register from before the hibernation (this value is passed
 * in the image header).
 */
unsigned long restore_cr3 __visible;
unsigned long temp_pgt __visible;
unsigned long relocated_restore_code __visible;

/**
 *	pfn_is_nosave - check if given pfn is in the 'nosave' section
 */
int pfn_is_nosave(unsigned long pfn)
{
	unsigned long nosave_begin_pfn;
	unsigned long nosave_end_pfn;

	nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
	nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;

	return pfn >= nosave_begin_pfn && pfn < nosave_end_pfn;
}

struct restore_data_record {
	unsigned long jump_address;
	unsigned long jump_address_phys;
	unsigned long cr3;
	unsigned long magic;
	unsigned long e820_checksum;
};

/**
 * compute_e820_crc32 - calculate crc32 of a given e820 table
 *
 * @table: the e820 table to be calculated
 *
 * Return: the resulting checksum
 */
static inline u32 compute_e820_crc32(struct e820_table *table)
{
	int size = offsetof(struct e820_table, entries) +
		sizeof(struct e820_entry) * table->nr_entries;

	return ~crc32_le(~0, (unsigned char const *)table, size);
}

#ifdef CONFIG_X86_64
#define RESTORE_MAGIC	0x23456789ABCDEF02UL
#else
#define RESTORE_MAGIC	0x12345679UL
#endif

/**
 *	arch_hibernation_header_save - populate the architecture specific part
 *		of a hibernation image header
 *	@addr: address to save the data at
 */
int arch_hibernation_header_save(void *addr, unsigned int max_size)
{
	struct restore_data_record *rdr = addr;

	if (max_size < sizeof(struct restore_data_record))
		return -EOVERFLOW;
	rdr->magic = RESTORE_MAGIC;
	rdr->jump_address = (unsigned long)restore_registers;
	rdr->jump_address_phys = __pa_symbol(restore_registers);

	/*
	 * The restore code fixes up CR3 and CR4 in the following sequence:
	 *
	 * [in hibernation asm]
	 * 1. CR3 <= temporary page tables
	 * 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
	 * 3. CR3 <= rdr->cr3
	 * 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
	 * [in restore_processor_state()]
	 * 5. CR4 <= saved CR4
	 * 6. CR3 <= saved CR3
	 *
	 * Our mmu_cr4_features has CR4.PCIDE=0, and toggling
	 * CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
	 * rdr->cr3 needs to point to valid page tables but must not
	 * have any of the PCID bits set.
	 */
	rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;

	rdr->e820_checksum = compute_e820_crc32(e820_table_firmware);
	return 0;
}

/**
 *	arch_hibernation_header_restore - read the architecture specific data
 *		from the hibernation image header
 *	@addr: address to read the data from
 */
int arch_hibernation_header_restore(void *addr)
{
	struct restore_data_record *rdr = addr;

	if (rdr->magic != RESTORE_MAGIC) {
		pr_crit("Unrecognized hibernate image header format!\n");
		return -EINVAL;
	}

	restore_jump_address = rdr->jump_address;
	jump_address_phys = rdr->jump_address_phys;
	restore_cr3 = rdr->cr3;

	if (rdr->e820_checksum != compute_e820_crc32(e820_table_firmware)) {
		pr_crit("Hibernate inconsistent memory map detected!\n");
		return -ENODEV;
	}

	return 0;
}

int relocate_restore_code(void)
{
	pgd_t *pgd;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	relocated_restore_code = get_safe_page(GFP_ATOMIC);
	if (!relocated_restore_code)
		return -ENOMEM;

	__memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);

	/* Make the page containing the relocated code executable */
	pgd = (pgd_t *)__va(read_cr3_pa()) +
		pgd_index(relocated_restore_code);
	p4d = p4d_offset(pgd, relocated_restore_code);
	if (p4d_leaf(*p4d)) {
		set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
		goto out;
	}
	pud = pud_offset(p4d, relocated_restore_code);
	if (pud_leaf(*pud)) {
		set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
		goto out;
	}
	pmd = pmd_offset(pud, relocated_restore_code);
	if (pmd_leaf(*pmd)) {
		set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
		goto out;
	}
	pte = pte_offset_kernel(pmd, relocated_restore_code);
	set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
out:
	__flush_tlb_all();
	return 0;
}

int arch_resume_nosmt(void)
{
	int ret = 0;
	/*
	 * We reached this while coming out of hibernation. This means
	 * that SMT siblings are sleeping in hlt, as mwait is not safe
	 * against control transition during resume (see comment in
	 * hibernate_resume_nonboot_cpu_disable()).
	 *
	 * If the resumed kernel has SMT disabled, we have to take all the
	 * SMT siblings out of hlt, and offline them again so that they
	 * end up in mwait proper.
	 *
	 * Called with hotplug disabled.
	 */
	cpu_hotplug_enable();
	if (cpu_smt_control == CPU_SMT_DISABLED ||
			cpu_smt_control == CPU_SMT_FORCE_DISABLED) {
		enum cpuhp_smt_control old = cpu_smt_control;

		ret = cpuhp_smt_enable();
		if (ret)
			goto out;
		ret = cpuhp_smt_disable(old);
		if (ret)
			goto out;
	}
out:
	cpu_hotplug_disable();
	return ret;
}