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// 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;
}
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