hibernate.c

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