arch/x86/power/hibernate_64.c - linux - Git at Google

 /*
  * 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 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 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;
 }
	/*
	* 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 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 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;
	}