diff options
Diffstat (limited to 'arch/x86/power/hibernate.c')
| -rw-r--r-- | arch/x86/power/hibernate.c | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/arch/x86/power/hibernate.c b/arch/x86/power/hibernate.c new file mode 100644 index 000000000000..bcddf09b5aa3 --- /dev/null +++ b/arch/x86/power/hibernate.c @@ -0,0 +1,248 @@ +// 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 <crypto/hash.h> + +#include <asm/e820/api.h> +#include <asm/init.h> +#include <asm/proto.h> +#include <asm/page.h> +#include <asm/pgtable.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; +} + + +#define MD5_DIGEST_SIZE 16 + +struct restore_data_record { + unsigned long jump_address; + unsigned long jump_address_phys; + unsigned long cr3; + unsigned long magic; + u8 e820_digest[MD5_DIGEST_SIZE]; +}; + +#if IS_BUILTIN(CONFIG_CRYPTO_MD5) +/** + * get_e820_md5 - calculate md5 according to given e820 table + * + * @table: the e820 table to be calculated + * @buf: the md5 result to be stored to + */ +static int get_e820_md5(struct e820_table *table, void *buf) +{ + struct crypto_shash *tfm; + struct shash_desc *desc; + int size; + int ret = 0; + + tfm = crypto_alloc_shash("md5", 0, 0); + if (IS_ERR(tfm)) + return -ENOMEM; + + desc = kmalloc(sizeof(struct shash_desc) + crypto_shash_descsize(tfm), + GFP_KERNEL); + if (!desc) { + ret = -ENOMEM; + goto free_tfm; + } + + desc->tfm = tfm; + desc->flags = 0; + + size = offsetof(struct e820_table, entries) + + sizeof(struct e820_entry) * table->nr_entries; + + if (crypto_shash_digest(desc, (u8 *)table, size, buf)) + ret = -EINVAL; + + kzfree(desc); + +free_tfm: + crypto_free_shash(tfm); + return ret; +} + +static int hibernation_e820_save(void *buf) +{ + return get_e820_md5(e820_table_firmware, buf); +} + +static bool hibernation_e820_mismatch(void *buf) +{ + int ret; + u8 result[MD5_DIGEST_SIZE]; + + memset(result, 0, MD5_DIGEST_SIZE); + /* If there is no digest in suspend kernel, let it go. */ + if (!memcmp(result, buf, MD5_DIGEST_SIZE)) + return false; + + ret = get_e820_md5(e820_table_firmware, result); + if (ret) + return true; + + return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false; +} +#else +static int hibernation_e820_save(void *buf) +{ + return 0; +} + +static bool hibernation_e820_mismatch(void *buf) +{ + /* If md5 is not builtin for restore kernel, let it go. */ + return false; +} +#endif + +#ifdef CONFIG_X86_64 +#define RESTORE_MAGIC 0x23456789ABCDEF01UL +#else +#define RESTORE_MAGIC 0x12345678UL +#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; + + return hibernation_e820_save(rdr->e820_digest); +} + +/** + * 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 (hibernation_e820_mismatch(rdr->e820_digest)) { + 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_large(*p4d)) { + set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX)); + goto out; + } + pud = pud_offset(p4d, relocated_restore_code); + if (pud_large(*pud)) { + set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX)); + goto out; + } + pmd = pmd_offset(pud, relocated_restore_code); + if (pmd_large(*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; +} |