[linux-2.6-block.git] / arch / x86 / power / hibernate_64.c

/*
 * Hibernation support for x86-64
 *
 * Distribute under GPLv2
 *
 * 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>

/* 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 = NULL;
	pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
	pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);

	/* Filter out unsupported __PAGE_KERNEL* bits: */
	pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
	pgprot_val(pgtable_prot)  &= __default_kernel_pte_mask;

	/*
	 * 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 (pgtable_l5_enabled) {
		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) | pgprot_val(pmd_text_prot)));
	set_pud(pud + pud_index(restore_jump_address),
		__pud(__pa(pmd) | pgprot_val(pgtable_prot)));
	if (p4d) {
		p4d_t new_p4d = __p4d(__pa(pud) | pgprot_val(pgtable_prot));
		pgd_t new_pgd = __pgd(__pa(p4d) | pgprot_val(pgtable_prot));

		set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
	} else {
		/* No p4d for 4-level paging: point the pgd to the pud page table */
		pgd_t new_pgd = __pgd(__pa(pud) | pgprot_val(pgtable_prot));
		set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
	}

	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;
}

asmlinkage 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;
}
Commit	Line	Data
ef8b03fa RW	1	/*
	2	* Hibernation support for x86-64
	3	*
	4	* Distribute under GPLv2
	5	*
	6	* Copyright (c) 2007 Rafael J. Wysocki <rjw@sisk.pl>
a2531293	7	* Copyright (c) 2002 Pavel Machek <pavel@ucw.cz>
ef8b03fa RW	8	* Copyright (c) 2001 Patrick Mochel <mochel@osdl.org>
	9	*/
	10
5a0e3ad6	11	#include <linux/gfp.h>
ef8b03fa RW	12	#include <linux/smp.h>
ef8b03fa RW	13	#include <linux/suspend.h>
62a03def CY	14	#include <linux/scatterlist.h>
	15	#include <linux/kdebug.h>
	16
	17	#include <crypto/hash.h>
8b78c21d	18
5520b7e7	19	#include <asm/e820/api.h>
8b78c21d	20	#include <asm/init.h>
ef8b03fa RW	21	#include <asm/proto.h>
	22	#include <asm/page.h>
	23	#include <asm/pgtable.h>
	24	#include <asm/mtrr.h>
7f8998c7	25	#include <asm/sections.h>
a8af7898	26	#include <asm/suspend.h>
65c0554b	27	#include <asm/tlbflush.h>
ef8b03fa	28
261f0ce5	29	/* Defined in hibernate_asm_64.S */
2605fc21	30	extern asmlinkage __visible int restore_image(void);
ef8b03fa RW	31
	32	/*
	33	* Address to jump to in the last phase of restore in order to get to the image
	34	* kernel's text (this value is passed in the image header).
	35	*/
d6efc2f7	36	unsigned long restore_jump_address __visible;
65c0554b	37	unsigned long jump_address_phys;
ef8b03fa RW	38
	39	/*
	40	* Value of the cr3 register from before the hibernation (this value is passed
	41	* in the image header).
	42	*/
d6efc2f7	43	unsigned long restore_cr3 __visible;
ef8b03fa	44
c226fab4	45	unsigned long temp_level4_pgt __visible;
ef8b03fa	46
65c0554b RW	47	unsigned long relocated_restore_code __visible;
65c0554b RW	48
c226fab4	49	static int set_up_temporary_text_mapping(pgd_t *pgd)
65c0554b RW	50	{
	51	pmd_t *pmd;
	52	pud_t *pud;
91f606a8	53	p4d_t *p4d = NULL;
fb43d6cb DH	54	pgprot_t pgtable_prot = __pgprot(_KERNPG_TABLE);
	55	pgprot_t pmd_text_prot = __pgprot(__PAGE_KERNEL_LARGE_EXEC);
	56
	57	/* Filter out unsupported __PAGE_KERNEL* bits: */
	58	pgprot_val(pmd_text_prot) &= __default_kernel_pte_mask;
	59	pgprot_val(pgtable_prot) &= __default_kernel_pte_mask;
65c0554b RW	60
	61	/*
	62	* The new mapping only has to cover the page containing the image
	63	* kernel's entry point (jump_address_phys), because the switch over to
	64	* it is carried out by relocated code running from a page allocated
	65	* specifically for this purpose and covered by the identity mapping, so
	66	* the temporary kernel text mapping is only needed for the final jump.
	67	* Moreover, in that mapping the virtual address of the image kernel's
	68	* entry point must be the same as its virtual address in the image
	69	* kernel (restore_jump_address), so the image kernel's
	70	* restore_registers() code doesn't find itself in a different area of
	71	* the virtual address space after switching over to the original page
	72	* tables used by the image kernel.
	73	*/
06c830a4	74
91f606a8	75	if (pgtable_l5_enabled) {
06c830a4 KS	76	p4d = (p4d_t *)get_safe_page(GFP_ATOMIC);
	77	if (!p4d)
	78	return -ENOMEM;
	79	}
	80
65c0554b RW	81	pud = (pud_t *)get_safe_page(GFP_ATOMIC);
	82	if (!pud)
	83	return -ENOMEM;
	84
	85	pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
	86	if (!pmd)
	87	return -ENOMEM;
	88
	89	set_pmd(pmd + pmd_index(restore_jump_address),
fb43d6cb	90	__pmd((jump_address_phys & PMD_MASK) \| pgprot_val(pmd_text_prot)));
65c0554b	91	set_pud(pud + pud_index(restore_jump_address),
fb43d6cb	92	__pud(__pa(pmd) \| pgprot_val(pgtable_prot)));
91f606a8	93	if (p4d) {
fb43d6cb DH	94	p4d_t new_p4d = __p4d(__pa(pud) \| pgprot_val(pgtable_prot));
	95	pgd_t new_pgd = __pgd(__pa(p4d) \| pgprot_val(pgtable_prot));
	96
	97	set_p4d(p4d + p4d_index(restore_jump_address), new_p4d);
	98	set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
06c830a4 KS	99	} else {
06c830a4 KS	100	/* No p4d for 4-level paging: point the pgd to the pud page table */
05189820	101	pgd_t new_pgd = __pgd(__pa(pud) \| pgprot_val(pgtable_prot));
fb43d6cb	102	set_pgd(pgd + pgd_index(restore_jump_address), new_pgd);
06c830a4	103	}
65c0554b RW	104
	105	return 0;
	106	}
ef8b03fa	107
8b78c21d	108	static void alloc_pgt_page(void context)
ef8b03fa	109	{
8b78c21d	110	return (void *)get_safe_page(GFP_ATOMIC);
ef8b03fa RW	111	}
	112
	113	static int set_up_temporary_mappings(void)
	114	{
8b78c21d YL	115	struct x86_mapping_info info = {
8b78c21d YL	116	.alloc_pgt_page = alloc_pgt_page,
66aad4fd	117	.page_flag = __PAGE_KERNEL_LARGE_EXEC,
e4630fdd	118	.offset = __PAGE_OFFSET,
8b78c21d YL	119	};
8b78c21d YL	120	unsigned long mstart, mend;
c226fab4	121	pgd_t *pgd;
8b78c21d YL	122	int result;
8b78c21d YL	123	int i;
ef8b03fa	124
c226fab4 RW	125	pgd = (pgd_t *)get_safe_page(GFP_ATOMIC);
c226fab4 RW	126	if (!pgd)
ef8b03fa RW	127	return -ENOMEM;
ef8b03fa RW	128
65c0554b	129	/* Prepare a temporary mapping for the kernel text */
c226fab4	130	result = set_up_temporary_text_mapping(pgd);
65c0554b RW	131	if (result)
65c0554b RW	132	return result;
ef8b03fa RW	133
ef8b03fa RW	134	/* Set up the direct mapping from scratch */
8b78c21d YL	135	for (i = 0; i < nr_pfn_mapped; i++) {
	136	mstart = pfn_mapped[i].start << PAGE_SHIFT;
	137	mend = pfn_mapped[i].end << PAGE_SHIFT;
	138
c226fab4	139	result = kernel_ident_mapping_init(&info, pgd, mstart, mend);
8b78c21d YL	140	if (result)
8b78c21d YL	141	return result;
ef8b03fa	142	}
8b78c21d	143
5d87f493	144	temp_level4_pgt = __pa(pgd);
ef8b03fa RW	145	return 0;
	146	}
	147
65c0554b RW	148	static int relocate_restore_code(void)
	149	{
	150	pgd_t *pgd;
06c830a4	151	p4d_t *p4d;
65c0554b	152	pud_t *pud;
06c830a4 KS	153	pmd_t *pmd;
06c830a4 KS	154	pte_t *pte;
65c0554b RW	155
	156	relocated_restore_code = get_safe_page(GFP_ATOMIC);
	157	if (!relocated_restore_code)
	158	return -ENOMEM;
	159
c0944883	160	memcpy((void *)relocated_restore_code, core_restore_code, PAGE_SIZE);
65c0554b RW	161
65c0554b RW	162	/* Make the page containing the relocated code executable */
6c690ee1 AL	163	pgd = (pgd_t *)__va(read_cr3_pa()) +
6c690ee1 AL	164	pgd_index(relocated_restore_code);
06c830a4 KS	165	p4d = p4d_offset(pgd, relocated_restore_code);
	166	if (p4d_large(*p4d)) {
	167	set_p4d(p4d, __p4d(p4d_val(*p4d) & ~_PAGE_NX));
	168	goto out;
	169	}
	170	pud = pud_offset(p4d, relocated_restore_code);
65c0554b RW	171	if (pud_large(*pud)) {
65c0554b RW	172	set_pud(pud, __pud(pud_val(*pud) & ~_PAGE_NX));
06c830a4 KS	173	goto out;
	174	}
	175	pmd = pmd_offset(pud, relocated_restore_code);
	176	if (pmd_large(*pmd)) {
	177	set_pmd(pmd, __pmd(pmd_val(*pmd) & ~_PAGE_NX));
	178	goto out;
65c0554b	179	}
06c830a4 KS	180	pte = pte_offset_kernel(pmd, relocated_restore_code);
	181	set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_NX));
	182	out:
65c0554b	183	__flush_tlb_all();
65c0554b RW	184	return 0;
	185	}
	186
328008a7	187	asmlinkage int swsusp_arch_resume(void)
ef8b03fa RW	188	{
	189	int error;
	190
	191	/* We have got enough memory and from now on we cannot recover */
65c0554b RW	192	error = set_up_temporary_mappings();
65c0554b RW	193	if (error)
ef8b03fa RW	194	return error;
ef8b03fa RW	195
65c0554b RW	196	error = relocate_restore_code();
	197	if (error)
	198	return error;
ef8b03fa RW	199
	200	restore_image();
	201	return 0;
	202	}
	203
	204	/*
	205	* pfn_is_nosave - check if given pfn is in the 'nosave' section
	206	*/
	207
	208	int pfn_is_nosave(unsigned long pfn)
	209	{
	210	unsigned long nosave_begin_pfn = __pa_symbol(&__nosave_begin) >> PAGE_SHIFT;
	211	unsigned long nosave_end_pfn = PAGE_ALIGN(__pa_symbol(&__nosave_end)) >> PAGE_SHIFT;
	212	return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
	213	}
	214
62a03def CY	215	#define MD5_DIGEST_SIZE 16
62a03def CY	216
ef8b03fa RW	217	struct restore_data_record {
ef8b03fa RW	218	unsigned long jump_address;
65c0554b	219	unsigned long jump_address_phys;
ef8b03fa RW	220	unsigned long cr3;
ef8b03fa RW	221	unsigned long magic;
62a03def	222	u8 e820_digest[MD5_DIGEST_SIZE];
ef8b03fa RW	223	};
ef8b03fa RW	224
62a03def CY	225	#define RESTORE_MAGIC 0x23456789ABCDEF01UL
	226
	227	#if IS_BUILTIN(CONFIG_CRYPTO_MD5)
	228	/**
bf495573	229	* get_e820_md5 - calculate md5 according to given e820 table
62a03def	230	*
bf495573	231	* @table: the e820 table to be calculated
62a03def CY	232	* @buf: the md5 result to be stored to
62a03def CY	233	*/
bf495573	234	static int get_e820_md5(struct e820_table table, void buf)
62a03def CY	235	{
	236	struct scatterlist sg;
	237	struct crypto_ahash *tfm;
	238	int size;
	239	int ret = 0;
	240
	241	tfm = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
	242	if (IS_ERR(tfm))
	243	return -ENOMEM;
	244
	245	{
	246	AHASH_REQUEST_ON_STACK(req, tfm);
bf495573	247	size = offsetof(struct e820_table, entries) + sizeof(struct e820_entry) * table->nr_entries;
62a03def	248	ahash_request_set_tfm(req, tfm);
bf495573	249	sg_init_one(&sg, (u8 *)table, size);
62a03def CY	250	ahash_request_set_callback(req, 0, NULL, NULL);
	251	ahash_request_set_crypt(req, &sg, buf, size);
	252
	253	if (crypto_ahash_digest(req))
	254	ret = -EINVAL;
	255	ahash_request_zero(req);
	256	}
	257	crypto_free_ahash(tfm);
	258
	259	return ret;
	260	}
	261
	262	static void hibernation_e820_save(void *buf)
	263	{
544a0f47	264	get_e820_md5(e820_table_firmware, buf);
62a03def CY	265	}
	266
	267	static bool hibernation_e820_mismatch(void *buf)
	268	{
	269	int ret;
	270	u8 result[MD5_DIGEST_SIZE];
	271
	272	memset(result, 0, MD5_DIGEST_SIZE);
	273	/* If there is no digest in suspend kernel, let it go. */
	274	if (!memcmp(result, buf, MD5_DIGEST_SIZE))
	275	return false;
	276
544a0f47	277	ret = get_e820_md5(e820_table_firmware, result);
62a03def CY	278	if (ret)
	279	return true;
	280
	281	return memcmp(result, buf, MD5_DIGEST_SIZE) ? true : false;
	282	}
	283	#else
	284	static void hibernation_e820_save(void *buf)
	285	{
	286	}
	287
	288	static bool hibernation_e820_mismatch(void *buf)
	289	{
	290	/* If md5 is not builtin for restore kernel, let it go. */
	291	return false;
	292	}
	293	#endif
ef8b03fa RW	294
	295	/**
	296	* arch_hibernation_header_save - populate the architecture specific part
	297	* of a hibernation image header
	298	* @addr: address to save the data at
	299	*/
	300	int arch_hibernation_header_save(void *addr, unsigned int max_size)
	301	{
	302	struct restore_data_record *rdr = addr;
	303
	304	if (max_size < sizeof(struct restore_data_record))
	305	return -EOVERFLOW;
c0944883 KC	306	rdr->jump_address = (unsigned long)restore_registers;
c0944883 KC	307	rdr->jump_address_phys = __pa_symbol(restore_registers);
f34902c5 AL	308
	309	/*
	310	* The restore code fixes up CR3 and CR4 in the following sequence:
	311	*
	312	* [in hibernation asm]
	313	* 1. CR3 <= temporary page tables
	314	* 2. CR4 <= mmu_cr4_features (from the kernel that restores us)
	315	* 3. CR3 <= rdr->cr3
	316	* 4. CR4 <= mmu_cr4_features (from us, i.e. the image kernel)
	317	* [in restore_processor_state()]
	318	* 5. CR4 <= saved CR4
	319	* 6. CR3 <= saved CR3
	320	*
	321	* Our mmu_cr4_features has CR4.PCIDE=0, and toggling
	322	* CR4.PCIDE while CR3's PCID bits are nonzero is illegal, so
	323	* rdr->cr3 needs to point to valid page tables but must not
	324	* have any of the PCID bits set.
	325	*/
	326	rdr->cr3 = restore_cr3 & ~CR3_PCID_MASK;
	327
ef8b03fa	328	rdr->magic = RESTORE_MAGIC;
62a03def CY	329
	330	hibernation_e820_save(rdr->e820_digest);
	331
ef8b03fa RW	332	return 0;
	333	}
	334
	335	/**
	336	* arch_hibernation_header_restore - read the architecture specific data
	337	* from the hibernation image header
	338	* @addr: address to read the data from
	339	*/
	340	int arch_hibernation_header_restore(void *addr)
	341	{
	342	struct restore_data_record *rdr = addr;
	343
	344	restore_jump_address = rdr->jump_address;
65c0554b	345	jump_address_phys = rdr->jump_address_phys;
ef8b03fa	346	restore_cr3 = rdr->cr3;
62a03def CY	347
	348	if (rdr->magic != RESTORE_MAGIC) {
	349	pr_crit("Unrecognized hibernate image header format!\n");
	350	return -EINVAL;
	351	}
	352
	353	if (hibernation_e820_mismatch(rdr->e820_digest)) {
	354	pr_crit("Hibernate inconsistent memory map detected!\n");
	355	return -ENODEV;
	356	}
	357
	358	return 0;
ef8b03fa	359	}