// SPDX-License-Identifier: GPL-2.0 /* * Hibernation support for x86 * * Copyright (c) 2007 Rafael J. Wysocki * Copyright (c) 2002 Pavel Machek * Copyright (c) 2001 Patrick Mochel */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * 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; }