/* * Hibernation support for x86-64 * * Distribute under GPLv2 * * 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 /* Defined in hibernate_asm_64.S */ extern asmlinkage __visible int restore_image(void); /* * 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_level4_pgt __visible; unsigned long relocated_restore_code __visible; static int set_up_temporary_text_mapping(pgd_t *pgd) { pmd_t *pmd; pud_t *pud; p4d_t *p4d; /* * The new mapping only has to cover the page containing the image * kernel's entry point (jump_address_phys), because the switch over to * it is carried out by relocated code running from a page allocated * specifically for this purpose and covered by the identity mapping, so * the temporary kernel text mapping is only needed for the final jump. * Moreover, in that mapping the virtual address of the image kernel's * entry point must be the same as its virtual address in the image * kernel (restore_jump_address), so the image kernel's * restore_registers() code doesn't find itself in a different area of * the virtual address space after switching over to the original page * tables used by the image kernel. */ if (IS_ENABLED(CONFIG_X86_5LEVEL)) { p4d = (p4d_t *)get_safe_page(GFP_ATOMIC); if (!p4d) return -ENOMEM; } pud = (pud_t *)get_safe_page(GFP_ATOMIC); if (!pud) return -ENOMEM; pmd = (pmd_t *)get_safe_page(GFP_ATOMIC); if (!pmd) return -ENOMEM; set_pmd(pmd + pmd_index(restore_jump_address), __pmd((jump_address_phys & PMD_MASK) | __PAGE_KERNEL_LARGE_EXEC)); set_pud(pud + pud_index(restore_jump_address), __pud(__pa(pmd) | _KERNPG_TABLE)); if (IS_ENABLED(CONFIG_X86_5LEVEL)) { set_p4d(p4d + p4d_index(restore_jump_address), __p4d(__pa(pud) | _KERNPG_TABLE)); set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(p4d) | _KERNPG_TABLE)); } else { /* No p4d for 4-level paging: point the pgd to the pud page table */ set_pgd(pgd + pgd_index(restore_jump_address), __pgd(__pa(pud) | _KERNPG_TABLE)); } return 0; } static void *alloc_pgt_page(void *context) { return (void *)get_safe_page(GFP_ATOMIC); } static int set_up_temporary_mappings(void) { struct x86_mapping_info info = { .alloc_pgt_page = alloc_pgt_page, .page_flag = __PAGE_KERNEL_LARGE_EXEC, .offset = __PAGE_OFFSET, }; unsigned long mstart, mend; pgd_t *pgd; int result; int i; pgd = (pgd_t *)get_safe_page(GFP_ATOMIC); if (!pgd) return -ENOMEM; /* Prepare a temporary mapping for the kernel text */ result = set_up_temporary_text_mapping(pgd); if (result) return result; /* Set up the direct mapping from scratch */ for (i = 0; i < nr_pfn_mapped; i++) { mstart = pfn_mapped[i].start << PAGE_SHIFT; mend = pfn_mapped[i].end << PAGE_SHIFT; result = kernel_ident_mapping_init(&info, pgd, mstart, mend); if (result) return result; } temp_level4_pgt = __pa(pgd); return 0; } static 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; } int swsusp_arch_resume(void) { int error; /* We have got enough memory and from now on we cannot recover */ error = set_up_temporary_mappings(); if (error) return error; error = relocate_restore_code(); if (error) return error; restore_image(); return 0; } /* * pfn_is_nosave - check if given pfn is in the 'nosave' section */ int pfn_is_nosave(unsigned long pfn) { unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT; unsigned long 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]; }; #define RESTORE_MAGIC 0x23456789ABCDEF01UL #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 scatterlist sg; struct crypto_ahash *tfm; int size; int ret = 0; tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC); if (IS_ERR(tfm)) return -ENOMEM; { AHASH_REQUEST_ON_STACK(req, tfm); size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries; ahash_request_set_tfm(req, tfm); sg_init_one(&sg, (u8 *)table, size); ahash_request_set_callback(req, 0, NULL, NULL); ahash_request_set_crypt(req, &sg, buf, size); if (crypto_ahash_digest(req)) ret = -EINVAL; ahash_request_zero(req); } crypto_free_ahash(tfm); return ret; } static void hibernation_e820_save(void *buf) { 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 void hibernation_e820_save(void *buf) { } static bool hibernation_e820_mismatch(void *buf) { /* If md5 is not builtin for restore kernel, let it go. */ return false; } #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->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->magic = RESTORE_MAGIC; hibernation_e820_save(rdr->e820_digest); 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; restore_jump_address = rdr->jump_address; jump_address_phys = rdr->jump_address_phys; restore_cr3 = rdr->cr3; if (rdr->magic != RESTORE_MAGIC) { pr_crit("Unrecognized hibernate image header format!\n"); return -EINVAL; } if (hibernation_e820_mismatch(rdr->e820_digest)) { pr_crit("Hibernate inconsistent memory map detected!\n"); return -ENODEV; } return 0; }