arch/riscv/kernel/hibernate.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Hibernation support for RISCV
  *
  * Copyright (C) 2023 StarFive Technology Co., Ltd.
  *
  * Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
  */

 #include <asm/barrier.h>
 #include <asm/cacheflush.h>
 #include <asm/mmu_context.h>
 #include <asm/page.h>
 #include <asm/pgalloc.h>
 #include <asm/pgtable.h>
 #include <asm/sections.h>
 #include <asm/set_memory.h>
 #include <asm/smp.h>
 #include <asm/suspend.h>

 #include <linux/cpu.h>
 #include <linux/memblock.h>
 #include <linux/pm.h>
 #include <linux/sched.h>
 #include <linux/suspend.h>
 #include <linux/utsname.h>

 /* The logical cpu number we should resume on, initialised to a non-cpu number. */
 static int sleep_cpu = -EINVAL;

 /* Pointer to the temporary resume page table. */
 static pgd_t *resume_pg_dir;

 /* CPU context to be saved. */
 struct suspend_context *hibernate_cpu_context;
 EXPORT_SYMBOL_GPL(hibernate_cpu_context);

 unsigned long relocated_restore_code;
 EXPORT_SYMBOL_GPL(relocated_restore_code);

 /**
  * struct arch_hibernate_hdr_invariants - container to store kernel build version.
  * @uts_version: to save the build number and date so that we do not resume with
  *		a different kernel.
  */
 struct arch_hibernate_hdr_invariants {
 	char		uts_version[__NEW_UTS_LEN + 1];
 };

 /**
  * struct arch_hibernate_hdr - helper parameters that help us to restore the image.
  * @invariants: container to store kernel build version.
  * @hartid: to make sure same boot_cpu executes the hibernate/restore code.
  * @saved_satp: original page table used by the hibernated image.
  * @restore_cpu_addr: the kernel's image address to restore the CPU context.
  */
 static struct arch_hibernate_hdr {
 	struct arch_hibernate_hdr_invariants invariants;
 	unsigned long	hartid;
 	unsigned long	saved_satp;
 	unsigned long	restore_cpu_addr;
 } resume_hdr;

 static void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
 {
 	memset(i, 0, sizeof(*i));
 	memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
 }

 /*
  * Check if the given pfn is in the 'nosave' section.
  */
 int pfn_is_nosave(unsigned long pfn)
 {
 	unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
 	unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);

 	return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn));
 }

 void notrace save_processor_state(void)
 {
 }

 void notrace restore_processor_state(void)
 {
 }

 /*
  * Helper parameters need to be saved to the hibernation image header.
  */
 int arch_hibernation_header_save(void *addr, unsigned int max_size)
 {
 	struct arch_hibernate_hdr *hdr = addr;

 	if (max_size < sizeof(*hdr))
 		return -EOVERFLOW;

 	arch_hdr_invariants(&hdr->invariants);

 	hdr->hartid = cpuid_to_hartid_map(sleep_cpu);
 	hdr->saved_satp = csr_read(CSR_SATP);
 	hdr->restore_cpu_addr = (unsigned long)__hibernate_cpu_resume;

 	return 0;
 }
 EXPORT_SYMBOL_GPL(arch_hibernation_header_save);

 /*
  * Retrieve the helper parameters from the hibernation image header.
  */
 int arch_hibernation_header_restore(void *addr)
 {
 	struct arch_hibernate_hdr_invariants invariants;
 	struct arch_hibernate_hdr *hdr = addr;
 	int ret = 0;

 	arch_hdr_invariants(&invariants);

 	if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
 		pr_crit("Hibernate image not generated by this kernel!\n");
 		return -EINVAL;
 	}

 	sleep_cpu = riscv_hartid_to_cpuid(hdr->hartid);
 	if (sleep_cpu < 0) {
 		pr_crit("Hibernated on a CPU not known to this kernel!\n");
 		sleep_cpu = -EINVAL;
 		return -EINVAL;
 	}

 #ifdef CONFIG_SMP
 	ret = bringup_hibernate_cpu(sleep_cpu);
 	if (ret) {
 		sleep_cpu = -EINVAL;
 		return ret;
 	}
 #endif
 	resume_hdr = *hdr;

 	return ret;
 }
 EXPORT_SYMBOL_GPL(arch_hibernation_header_restore);

 int swsusp_arch_suspend(void)
 {
 	int ret = 0;

 	if (__cpu_suspend_enter(hibernate_cpu_context)) {
 		sleep_cpu = smp_processor_id();
 		suspend_save_csrs(hibernate_cpu_context);
 		ret = swsusp_save();
 	} else {
 		suspend_restore_csrs(hibernate_cpu_context);
 		flush_tlb_all();
 		flush_icache_all();

 		/*
 		 * Tell the hibernation core that we've just restored the memory.
 		 */
 		in_suspend = 0;
 		sleep_cpu = -EINVAL;
 	}

 	return ret;
 }

 static int temp_pgtable_map_pte(pmd_t *dst_pmdp, pmd_t *src_pmdp, unsigned long start,
 				unsigned long end, pgprot_t prot)
 {
 	pte_t *src_ptep;
 	pte_t *dst_ptep;

 	if (pmd_none(READ_ONCE(*dst_pmdp))) {
 		dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC);
 		if (!dst_ptep)
 			return -ENOMEM;

 		pmd_populate_kernel(NULL, dst_pmdp, dst_ptep);
 	}

 	dst_ptep = pte_offset_kernel(dst_pmdp, start);
 	src_ptep = pte_offset_kernel(src_pmdp, start);

 	do {
 		pte_t pte = READ_ONCE(*src_ptep);

 		if (pte_present(pte))
 			set_pte(dst_ptep, __pte(pte_val(pte) | pgprot_val(prot)));
 	} while (dst_ptep++, src_ptep++, start += PAGE_SIZE, start < end);

 	return 0;
 }

 static int temp_pgtable_map_pmd(pud_t *dst_pudp, pud_t *src_pudp, unsigned long start,
 				unsigned long end, pgprot_t prot)
 {
 	unsigned long next;
 	unsigned long ret;
 	pmd_t *src_pmdp;
 	pmd_t *dst_pmdp;

 	if (pud_none(READ_ONCE(*dst_pudp))) {
 		dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC);
 		if (!dst_pmdp)
 			return -ENOMEM;

 		pud_populate(NULL, dst_pudp, dst_pmdp);
 	}

 	dst_pmdp = pmd_offset(dst_pudp, start);
 	src_pmdp = pmd_offset(src_pudp, start);

 	do {
 		pmd_t pmd = READ_ONCE(*src_pmdp);

 		next = pmd_addr_end(start, end);

 		if (pmd_none(pmd))
 			continue;

 		if (pmd_leaf(pmd)) {
 			set_pmd(dst_pmdp, __pmd(pmd_val(pmd) | pgprot_val(prot)));
 		} else {
 			ret = temp_pgtable_map_pte(dst_pmdp, src_pmdp, start, next, prot);
 			if (ret)
 				return -ENOMEM;
 		}
 	} while (dst_pmdp++, src_pmdp++, start = next, start != end);

 	return 0;
 }

 static int temp_pgtable_map_pud(p4d_t *dst_p4dp, p4d_t *src_p4dp, unsigned long start,
 				unsigned long end, pgprot_t prot)
 {
 	unsigned long next;
 	unsigned long ret;
 	pud_t *dst_pudp;
 	pud_t *src_pudp;

 	if (p4d_none(READ_ONCE(*dst_p4dp))) {
 		dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);
 		if (!dst_pudp)
 			return -ENOMEM;

 		p4d_populate(NULL, dst_p4dp, dst_pudp);
 	}

 	dst_pudp = pud_offset(dst_p4dp, start);
 	src_pudp = pud_offset(src_p4dp, start);

 	do {
 		pud_t pud = READ_ONCE(*src_pudp);

 		next = pud_addr_end(start, end);

 		if (pud_none(pud))
 			continue;

 		if (pud_leaf(pud)) {
 			set_pud(dst_pudp, __pud(pud_val(pud) | pgprot_val(prot)));
 		} else {
 			ret = temp_pgtable_map_pmd(dst_pudp, src_pudp, start, next, prot);
 			if (ret)
 				return -ENOMEM;
 		}
 	} while (dst_pudp++, src_pudp++, start = next, start != end);

 	return 0;
 }

 static int temp_pgtable_map_p4d(pgd_t *dst_pgdp, pgd_t *src_pgdp, unsigned long start,
 				unsigned long end, pgprot_t prot)
 {
 	unsigned long next;
 	unsigned long ret;
 	p4d_t *dst_p4dp;
 	p4d_t *src_p4dp;

 	if (pgd_none(READ_ONCE(*dst_pgdp))) {
 		dst_p4dp = (p4d_t *)get_safe_page(GFP_ATOMIC);
 		if (!dst_p4dp)
 			return -ENOMEM;

 		pgd_populate(NULL, dst_pgdp, dst_p4dp);
 	}

 	dst_p4dp = p4d_offset(dst_pgdp, start);
 	src_p4dp = p4d_offset(src_pgdp, start);

 	do {
 		p4d_t p4d = READ_ONCE(*src_p4dp);

 		next = p4d_addr_end(start, end);

 		if (p4d_none(p4d))
 			continue;

 		if (p4d_leaf(p4d)) {
 			set_p4d(dst_p4dp, __p4d(p4d_val(p4d) | pgprot_val(prot)));
 		} else {
 			ret = temp_pgtable_map_pud(dst_p4dp, src_p4dp, start, next, prot);
 			if (ret)
 				return -ENOMEM;
 		}
 	} while (dst_p4dp++, src_p4dp++, start = next, start != end);

 	return 0;
 }

 static int temp_pgtable_mapping(pgd_t *pgdp, unsigned long start, unsigned long end, pgprot_t prot)
 {
 	pgd_t *dst_pgdp = pgd_offset_pgd(pgdp, start);
 	pgd_t *src_pgdp = pgd_offset_k(start);
 	unsigned long next;
 	unsigned long ret;

 	do {
 		pgd_t pgd = READ_ONCE(*src_pgdp);

 		next = pgd_addr_end(start, end);

 		if (pgd_none(pgd))
 			continue;

 		if (pgd_leaf(pgd)) {
 			set_pgd(dst_pgdp, __pgd(pgd_val(pgd) | pgprot_val(prot)));
 		} else {
 			ret = temp_pgtable_map_p4d(dst_pgdp, src_pgdp, start, next, prot);
 			if (ret)
 				return -ENOMEM;
 		}
 	} while (dst_pgdp++, src_pgdp++, start = next, start != end);

 	return 0;
 }

 static unsigned long relocate_restore_code(void)
 {
 	void *page = (void *)get_safe_page(GFP_ATOMIC);

 	if (!page)
 		return -ENOMEM;

 	copy_page(page, hibernate_core_restore_code);

 	/* Make the page containing the relocated code executable. */
 	set_memory_x((unsigned long)page, 1);

 	return (unsigned long)page;
 }

 int swsusp_arch_resume(void)
 {
 	unsigned long end = (unsigned long)pfn_to_virt(max_low_pfn);
 	unsigned long start = PAGE_OFFSET;
 	int ret;

 	/*
 	 * Memory allocated by get_safe_page() will be dealt with by the hibernation core,
 	 * we don't need to free it here.
 	 */
 	resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
 	if (!resume_pg_dir)
 		return -ENOMEM;

 	/*
 	 * Create a temporary page table and map the whole linear region as executable and
 	 * writable.
 	 */
 	ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE | _PAGE_EXEC));
 	if (ret)
 		return ret;

 	/* Move the restore code to a new page so that it doesn't get overwritten by itself. */
 	relocated_restore_code = relocate_restore_code();
 	if (relocated_restore_code == -ENOMEM)
 		return -ENOMEM;

 	/*
 	 * Map the __hibernate_cpu_resume() address to the temporary page table so that the
 	 * restore code can jumps to it after finished restore the image. The next execution
 	 * code doesn't find itself in a different address space after switching over to the
 	 * original page table used by the hibernated image.
 	 * The __hibernate_cpu_resume() mapping is unnecessary for RV32 since the kernel and
 	 * linear addresses are identical, but different for RV64. To ensure consistency, we
 	 * map it for both RV32 and RV64 kernels.
 	 * Additionally, we should ensure that the page is writable before restoring the image.
 	 */
 	start = (unsigned long)resume_hdr.restore_cpu_addr;
 	end = start + PAGE_SIZE;

 	ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE));
 	if (ret)
 		return ret;

 	hibernate_restore_image(resume_hdr.saved_satp, (PFN_DOWN(__pa(resume_pg_dir)) | satp_mode),
 				resume_hdr.restore_cpu_addr);

 	return 0;
 }

 #ifdef CONFIG_PM_SLEEP_SMP
 int hibernate_resume_nonboot_cpu_disable(void)
 {
 	if (sleep_cpu < 0) {
 		pr_err("Failing to resume from hibernate on an unknown CPU\n");
 		return -ENODEV;
 	}

 	return freeze_secondary_cpus(sleep_cpu);
 }
 #endif

 static int __init riscv_hibernate_init(void)
 {
 	hibernate_cpu_context = kzalloc(sizeof(*hibernate_cpu_context), GFP_KERNEL);

 	if (WARN_ON(!hibernate_cpu_context))
 		return -ENOMEM;

 	return 0;
 }

 early_initcall(riscv_hibernate_init);
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Hibernation support for RISCV
	*
	* Copyright (C) 2023 StarFive Technology Co., Ltd.
	*
	* Author: Jee Heng Sia <jeeheng.sia@starfivetech.com>
	*/

	#include <asm/barrier.h>
	#include <asm/cacheflush.h>
	#include <asm/mmu_context.h>
	#include <asm/page.h>
	#include <asm/pgalloc.h>
	#include <asm/pgtable.h>
	#include <asm/sections.h>
	#include <asm/set_memory.h>
	#include <asm/smp.h>
	#include <asm/suspend.h>

	#include <linux/cpu.h>
	#include <linux/memblock.h>
	#include <linux/pm.h>
	#include <linux/sched.h>
	#include <linux/suspend.h>
	#include <linux/utsname.h>

	/* The logical cpu number we should resume on, initialised to a non-cpu number. */
	static int sleep_cpu = -EINVAL;

	/* Pointer to the temporary resume page table. */
	static pgd_t *resume_pg_dir;

	/* CPU context to be saved. */
	struct suspend_context *hibernate_cpu_context;
	EXPORT_SYMBOL_GPL(hibernate_cpu_context);

	unsigned long relocated_restore_code;
	EXPORT_SYMBOL_GPL(relocated_restore_code);

	/**
	* struct arch_hibernate_hdr_invariants - container to store kernel build version.
	* @uts_version: to save the build number and date so that we do not resume with
	* a different kernel.
	*/
	struct arch_hibernate_hdr_invariants {
	char uts_version[__NEW_UTS_LEN + 1];
	};

	/**
	* struct arch_hibernate_hdr - helper parameters that help us to restore the image.
	* @invariants: container to store kernel build version.
	* @hartid: to make sure same boot_cpu executes the hibernate/restore code.
	* @saved_satp: original page table used by the hibernated image.
	* @restore_cpu_addr: the kernel's image address to restore the CPU context.
	*/
	static struct arch_hibernate_hdr {
	struct arch_hibernate_hdr_invariants invariants;
	unsigned long hartid;
	unsigned long saved_satp;
	unsigned long restore_cpu_addr;
	} resume_hdr;

	static void arch_hdr_invariants(struct arch_hibernate_hdr_invariants *i)
	{
	memset(i, 0, sizeof(*i));
	memcpy(i->uts_version, init_utsname()->version, sizeof(i->uts_version));
	}

	/*
	* Check if the given pfn is in the 'nosave' section.
	*/
	int pfn_is_nosave(unsigned long pfn)
	{
	unsigned long nosave_begin_pfn = sym_to_pfn(&__nosave_begin);
	unsigned long nosave_end_pfn = sym_to_pfn(&__nosave_end - 1);

	return ((pfn >= nosave_begin_pfn) && (pfn <= nosave_end_pfn));
	}

	void notrace save_processor_state(void)
	{
	}

	void notrace restore_processor_state(void)
	{
	}

	/*
	* Helper parameters need to be saved to the hibernation image header.
	*/
	int arch_hibernation_header_save(void *addr, unsigned int max_size)
	{
	struct arch_hibernate_hdr *hdr = addr;

	if (max_size < sizeof(*hdr))
	return -EOVERFLOW;

	arch_hdr_invariants(&hdr->invariants);

	hdr->hartid = cpuid_to_hartid_map(sleep_cpu);
	hdr->saved_satp = csr_read(CSR_SATP);
	hdr->restore_cpu_addr = (unsigned long)__hibernate_cpu_resume;

	return 0;
	}
	EXPORT_SYMBOL_GPL(arch_hibernation_header_save);

	/*
	* Retrieve the helper parameters from the hibernation image header.
	*/
	int arch_hibernation_header_restore(void *addr)
	{
	struct arch_hibernate_hdr_invariants invariants;
	struct arch_hibernate_hdr *hdr = addr;
	int ret = 0;

	arch_hdr_invariants(&invariants);

	if (memcmp(&hdr->invariants, &invariants, sizeof(invariants))) {
	pr_crit("Hibernate image not generated by this kernel!\n");
	return -EINVAL;
	}

	sleep_cpu = riscv_hartid_to_cpuid(hdr->hartid);
	if (sleep_cpu < 0) {
	pr_crit("Hibernated on a CPU not known to this kernel!\n");
	sleep_cpu = -EINVAL;
	return -EINVAL;
	}

	#ifdef CONFIG_SMP
	ret = bringup_hibernate_cpu(sleep_cpu);
	if (ret) {
	sleep_cpu = -EINVAL;
	return ret;
	}
	#endif
	resume_hdr = *hdr;

	return ret;
	}
	EXPORT_SYMBOL_GPL(arch_hibernation_header_restore);

	int swsusp_arch_suspend(void)
	{
	int ret = 0;

	if (__cpu_suspend_enter(hibernate_cpu_context)) {
	sleep_cpu = smp_processor_id();
	suspend_save_csrs(hibernate_cpu_context);
	ret = swsusp_save();
	} else {
	suspend_restore_csrs(hibernate_cpu_context);
	flush_tlb_all();
	flush_icache_all();

	/*
	* Tell the hibernation core that we've just restored the memory.
	*/
	in_suspend = 0;
	sleep_cpu = -EINVAL;
	}

	return ret;
	}

	static int temp_pgtable_map_pte(pmd_t dst_pmdp, pmd_t src_pmdp, unsigned long start,
	unsigned long end, pgprot_t prot)
	{
	pte_t *src_ptep;
	pte_t *dst_ptep;

	if (pmd_none(READ_ONCE(*dst_pmdp))) {
	dst_ptep = (pte_t *)get_safe_page(GFP_ATOMIC);
	if (!dst_ptep)
	return -ENOMEM;

	pmd_populate_kernel(NULL, dst_pmdp, dst_ptep);
	}

	dst_ptep = pte_offset_kernel(dst_pmdp, start);
	src_ptep = pte_offset_kernel(src_pmdp, start);

	do {
	pte_t pte = READ_ONCE(*src_ptep);

	if (pte_present(pte))
	set_pte(dst_ptep, __pte(pte_val(pte) \| pgprot_val(prot)));
	} while (dst_ptep++, src_ptep++, start += PAGE_SIZE, start < end);

	return 0;
	}

	static int temp_pgtable_map_pmd(pud_t dst_pudp, pud_t src_pudp, unsigned long start,
	unsigned long end, pgprot_t prot)
	{
	unsigned long next;
	unsigned long ret;
	pmd_t *src_pmdp;
	pmd_t *dst_pmdp;

	if (pud_none(READ_ONCE(*dst_pudp))) {
	dst_pmdp = (pmd_t *)get_safe_page(GFP_ATOMIC);
	if (!dst_pmdp)
	return -ENOMEM;

	pud_populate(NULL, dst_pudp, dst_pmdp);
	}

	dst_pmdp = pmd_offset(dst_pudp, start);
	src_pmdp = pmd_offset(src_pudp, start);

	do {
	pmd_t pmd = READ_ONCE(*src_pmdp);

	next = pmd_addr_end(start, end);

	if (pmd_none(pmd))
	continue;

	if (pmd_leaf(pmd)) {
	set_pmd(dst_pmdp, __pmd(pmd_val(pmd) \| pgprot_val(prot)));
	} else {
	ret = temp_pgtable_map_pte(dst_pmdp, src_pmdp, start, next, prot);
	if (ret)
	return -ENOMEM;
	}
	} while (dst_pmdp++, src_pmdp++, start = next, start != end);

	return 0;
	}

	static int temp_pgtable_map_pud(p4d_t dst_p4dp, p4d_t src_p4dp, unsigned long start,
	unsigned long end, pgprot_t prot)
	{
	unsigned long next;
	unsigned long ret;
	pud_t *dst_pudp;
	pud_t *src_pudp;

	if (p4d_none(READ_ONCE(*dst_p4dp))) {
	dst_pudp = (pud_t *)get_safe_page(GFP_ATOMIC);
	if (!dst_pudp)
	return -ENOMEM;

	p4d_populate(NULL, dst_p4dp, dst_pudp);
	}

	dst_pudp = pud_offset(dst_p4dp, start);
	src_pudp = pud_offset(src_p4dp, start);

	do {
	pud_t pud = READ_ONCE(*src_pudp);

	next = pud_addr_end(start, end);

	if (pud_none(pud))
	continue;

	if (pud_leaf(pud)) {
	set_pud(dst_pudp, __pud(pud_val(pud) \| pgprot_val(prot)));
	} else {
	ret = temp_pgtable_map_pmd(dst_pudp, src_pudp, start, next, prot);
	if (ret)
	return -ENOMEM;
	}
	} while (dst_pudp++, src_pudp++, start = next, start != end);

	return 0;
	}

	static int temp_pgtable_map_p4d(pgd_t dst_pgdp, pgd_t src_pgdp, unsigned long start,
	unsigned long end, pgprot_t prot)
	{
	unsigned long next;
	unsigned long ret;
	p4d_t *dst_p4dp;
	p4d_t *src_p4dp;

	if (pgd_none(READ_ONCE(*dst_pgdp))) {
	dst_p4dp = (p4d_t *)get_safe_page(GFP_ATOMIC);
	if (!dst_p4dp)
	return -ENOMEM;

	pgd_populate(NULL, dst_pgdp, dst_p4dp);
	}

	dst_p4dp = p4d_offset(dst_pgdp, start);
	src_p4dp = p4d_offset(src_pgdp, start);

	do {
	p4d_t p4d = READ_ONCE(*src_p4dp);

	next = p4d_addr_end(start, end);

	if (p4d_none(p4d))
	continue;

	if (p4d_leaf(p4d)) {
	set_p4d(dst_p4dp, __p4d(p4d_val(p4d) \| pgprot_val(prot)));
	} else {
	ret = temp_pgtable_map_pud(dst_p4dp, src_p4dp, start, next, prot);
	if (ret)
	return -ENOMEM;
	}
	} while (dst_p4dp++, src_p4dp++, start = next, start != end);

	return 0;
	}

	static int temp_pgtable_mapping(pgd_t *pgdp, unsigned long start, unsigned long end, pgprot_t prot)
	{
	pgd_t *dst_pgdp = pgd_offset_pgd(pgdp, start);
	pgd_t *src_pgdp = pgd_offset_k(start);
	unsigned long next;
	unsigned long ret;

	do {
	pgd_t pgd = READ_ONCE(*src_pgdp);

	next = pgd_addr_end(start, end);

	if (pgd_none(pgd))
	continue;

	if (pgd_leaf(pgd)) {
	set_pgd(dst_pgdp, __pgd(pgd_val(pgd) \| pgprot_val(prot)));
	} else {
	ret = temp_pgtable_map_p4d(dst_pgdp, src_pgdp, start, next, prot);
	if (ret)
	return -ENOMEM;
	}
	} while (dst_pgdp++, src_pgdp++, start = next, start != end);

	return 0;
	}

	static unsigned long relocate_restore_code(void)
	{
	void page = (void )get_safe_page(GFP_ATOMIC);

	if (!page)
	return -ENOMEM;

	copy_page(page, hibernate_core_restore_code);

	/* Make the page containing the relocated code executable. */
	set_memory_x((unsigned long)page, 1);

	return (unsigned long)page;
	}

	int swsusp_arch_resume(void)
	{
	unsigned long end = (unsigned long)pfn_to_virt(max_low_pfn);
	unsigned long start = PAGE_OFFSET;
	int ret;

	/*
	* Memory allocated by get_safe_page() will be dealt with by the hibernation core,
	* we don't need to free it here.
	*/
	resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
	if (!resume_pg_dir)
	return -ENOMEM;

	/*
	* Create a temporary page table and map the whole linear region as executable and
	* writable.
	*/
	ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE \| _PAGE_EXEC));
	if (ret)
	return ret;

	/* Move the restore code to a new page so that it doesn't get overwritten by itself. */
	relocated_restore_code = relocate_restore_code();
	if (relocated_restore_code == -ENOMEM)
	return -ENOMEM;

	/*
	* Map the __hibernate_cpu_resume() address to the temporary page table so that the
	* restore code can jumps to it after finished restore the image. The next execution
	* code doesn't find itself in a different address space after switching over to the
	* original page table used by the hibernated image.
	* The __hibernate_cpu_resume() mapping is unnecessary for RV32 since the kernel and
	* linear addresses are identical, but different for RV64. To ensure consistency, we
	* map it for both RV32 and RV64 kernels.
	* Additionally, we should ensure that the page is writable before restoring the image.
	*/
	start = (unsigned long)resume_hdr.restore_cpu_addr;
	end = start + PAGE_SIZE;

	ret = temp_pgtable_mapping(resume_pg_dir, start, end, __pgprot(_PAGE_WRITE));
	if (ret)
	return ret;

	hibernate_restore_image(resume_hdr.saved_satp, (PFN_DOWN(__pa(resume_pg_dir)) \| satp_mode),
	resume_hdr.restore_cpu_addr);

	return 0;
	}

	#ifdef CONFIG_PM_SLEEP_SMP
	int hibernate_resume_nonboot_cpu_disable(void)
	{
	if (sleep_cpu < 0) {
	pr_err("Failing to resume from hibernate on an unknown CPU\n");
	return -ENODEV;
	}

	return freeze_secondary_cpus(sleep_cpu);
	}
	#endif

	static int __init riscv_hibernate_init(void)
	{
	hibernate_cpu_context = kzalloc(sizeof(*hibernate_cpu_context), GFP_KERNEL);

	if (WARN_ON(!hibernate_cpu_context))
	return -ENOMEM;

	return 0;
	}

	early_initcall(riscv_hibernate_init);