arch/x86/kernel/machine_kexec_64.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * handle transition of Linux booting another kernel
  * Copyright (C) 2002-2005 Eric Biederman  <ebiederm@xmission.com>
  */

 #define pr_fmt(fmt)	"kexec: " fmt

 #include <linux/mm.h>
 #include <linux/kexec.h>
 #include <linux/string.h>
 #include <linux/gfp.h>
 #include <linux/reboot.h>
 #include <linux/numa.h>
 #include <linux/ftrace.h>
 #include <linux/io.h>
 #include <linux/suspend.h>
 #include <linux/vmalloc.h>
 #include <linux/efi.h>

 #include <asm/init.h>
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mmu_context.h>
 #include <asm/io_apic.h>
 #include <asm/debugreg.h>
 #include <asm/kexec-bzimage64.h>
 #include <asm/setup.h>
 #include <asm/set_memory.h>

 #ifdef CONFIG_ACPI
 /*
  * Used while adding mapping for ACPI tables.
  * Can be reused when other iomem regions need be mapped
  */
 struct init_pgtable_data {
 	struct x86_mapping_info *info;
 	pgd_t *level4p;
 };

 static int mem_region_callback(struct resource *res, void *arg)
 {
 	struct init_pgtable_data *data = arg;
 	unsigned long mstart, mend;

 	mstart = res->start;
 	mend = mstart + resource_size(res) - 1;

 	return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend);
 }

 static int
 map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p)
 {
 	struct init_pgtable_data data;
 	unsigned long flags;
 	int ret;

 	data.info = info;
 	data.level4p = level4p;
 	flags = IORESOURCE_MEM | IORESOURCE_BUSY;

 	ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1,
 				  &data, mem_region_callback);
 	if (ret && ret != -EINVAL)
 		return ret;

 	/* ACPI tables could be located in ACPI Non-volatile Storage region */
 	ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1,
 				  &data, mem_region_callback);
 	if (ret && ret != -EINVAL)
 		return ret;

 	return 0;
 }
 #else
 static int map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) { return 0; }
 #endif

 #ifdef CONFIG_KEXEC_FILE
 const struct kexec_file_ops * const kexec_file_loaders[] = {
 		&kexec_bzImage64_ops,
 		NULL
 };
 #endif

 static int
 map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p)
 {
 #ifdef CONFIG_EFI
 	unsigned long mstart, mend;

 	if (!efi_enabled(EFI_BOOT))
 		return 0;

 	mstart = (boot_params.efi_info.efi_systab |
 			((u64)boot_params.efi_info.efi_systab_hi<<32));

 	if (efi_enabled(EFI_64BIT))
 		mend = mstart + sizeof(efi_system_table_64_t);
 	else
 		mend = mstart + sizeof(efi_system_table_32_t);

 	if (!mstart)
 		return 0;

 	return kernel_ident_mapping_init(info, level4p, mstart, mend);
 #endif
 	return 0;
 }

 static void free_transition_pgtable(struct kimage *image)
 {
 	free_page((unsigned long)image->arch.p4d);
 	image->arch.p4d = NULL;
 	free_page((unsigned long)image->arch.pud);
 	image->arch.pud = NULL;
 	free_page((unsigned long)image->arch.pmd);
 	image->arch.pmd = NULL;
 	free_page((unsigned long)image->arch.pte);
 	image->arch.pte = NULL;
 }

 static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
 {
 	pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
 	unsigned long vaddr, paddr;
 	int result = -ENOMEM;
 	p4d_t *p4d;
 	pud_t *pud;
 	pmd_t *pmd;
 	pte_t *pte;

 	vaddr = (unsigned long)relocate_kernel;
 	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
 	pgd += pgd_index(vaddr);
 	if (!pgd_present(*pgd)) {
 		p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL);
 		if (!p4d)
 			goto err;
 		image->arch.p4d = p4d;
 		set_pgd(pgd, __pgd(__pa(p4d) | _KERNPG_TABLE));
 	}
 	p4d = p4d_offset(pgd, vaddr);
 	if (!p4d_present(*p4d)) {
 		pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
 		if (!pud)
 			goto err;
 		image->arch.pud = pud;
 		set_p4d(p4d, __p4d(__pa(pud) | _KERNPG_TABLE));
 	}
 	pud = pud_offset(p4d, vaddr);
 	if (!pud_present(*pud)) {
 		pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
 		if (!pmd)
 			goto err;
 		image->arch.pmd = pmd;
 		set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
 	}
 	pmd = pmd_offset(pud, vaddr);
 	if (!pmd_present(*pmd)) {
 		pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
 		if (!pte)
 			goto err;
 		image->arch.pte = pte;
 		set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
 	}
 	pte = pte_offset_kernel(pmd, vaddr);

 	if (sev_active())
 		prot = PAGE_KERNEL_EXEC;

 	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
 	return 0;
 err:
 	return result;
 }

 static void *alloc_pgt_page(void *data)
 {
 	struct kimage *image = (struct kimage *)data;
 	struct page *page;
 	void *p = NULL;

 	page = kimage_alloc_control_pages(image, 0);
 	if (page) {
 		p = page_address(page);
 		clear_page(p);
 	}

 	return p;
 }

 static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 {
 	struct x86_mapping_info info = {
 		.alloc_pgt_page	= alloc_pgt_page,
 		.context	= image,
 		.page_flag	= __PAGE_KERNEL_LARGE_EXEC,
 		.kernpg_flag	= _KERNPG_TABLE_NOENC,
 	};
 	unsigned long mstart, mend;
 	pgd_t *level4p;
 	int result;
 	int i;

 	level4p = (pgd_t *)__va(start_pgtable);
 	clear_page(level4p);

 	if (sev_active()) {
 		info.page_flag   |= _PAGE_ENC;
 		info.kernpg_flag |= _PAGE_ENC;
 	}

 	if (direct_gbpages)
 		info.direct_gbpages = true;

 	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,
 						 level4p, mstart, mend);
 		if (result)
 			return result;
 	}

 	/*
 	 * segments's mem ranges could be outside 0 ~ max_pfn,
 	 * for example when jump back to original kernel from kexeced kernel.
 	 * or first kernel is booted with user mem map, and second kernel
 	 * could be loaded out of that range.
 	 */
 	for (i = 0; i < image->nr_segments; i++) {
 		mstart = image->segment[i].mem;
 		mend   = mstart + image->segment[i].memsz;

 		result = kernel_ident_mapping_init(&info,
 						 level4p, mstart, mend);

 		if (result)
 			return result;
 	}

 	/*
 	 * Prepare EFI systab and ACPI tables for kexec kernel since they are
 	 * not covered by pfn_mapped.
 	 */
 	result = map_efi_systab(&info, level4p);
 	if (result)
 		return result;

 	result = map_acpi_tables(&info, level4p);
 	if (result)
 		return result;

 	return init_transition_pgtable(image, level4p);
 }

 static void set_idt(void *newidt, u16 limit)
 {
 	struct desc_ptr curidt;

 	/* x86-64 supports unaliged loads & stores */
 	curidt.size    = limit;
 	curidt.address = (unsigned long)newidt;

 	__asm__ __volatile__ (
 		"lidtq %0\n"
 		: : "m" (curidt)
 		);
 };


 static void set_gdt(void *newgdt, u16 limit)
 {
 	struct desc_ptr curgdt;

 	/* x86-64 supports unaligned loads & stores */
 	curgdt.size    = limit;
 	curgdt.address = (unsigned long)newgdt;

 	__asm__ __volatile__ (
 		"lgdtq %0\n"
 		: : "m" (curgdt)
 		);
 };

 static void load_segments(void)
 {
 	__asm__ __volatile__ (
 		"\tmovl %0,%%ds\n"
 		"\tmovl %0,%%es\n"
 		"\tmovl %0,%%ss\n"
 		"\tmovl %0,%%fs\n"
 		"\tmovl %0,%%gs\n"
 		: : "a" (__KERNEL_DS) : "memory"
 		);
 }

 #ifdef CONFIG_KEXEC_FILE
 /* Update purgatory as needed after various image segments have been prepared */
 static int arch_update_purgatory(struct kimage *image)
 {
 	int ret = 0;

 	if (!image->file_mode)
 		return 0;

 	/* Setup copying of backup region */
 	if (image->type == KEXEC_TYPE_CRASH) {
 		ret = kexec_purgatory_get_set_symbol(image,
 				"purgatory_backup_dest",
 				&image->arch.backup_load_addr,
 				sizeof(image->arch.backup_load_addr), 0);
 		if (ret)
 			return ret;

 		ret = kexec_purgatory_get_set_symbol(image,
 				"purgatory_backup_src",
 				&image->arch.backup_src_start,
 				sizeof(image->arch.backup_src_start), 0);
 		if (ret)
 			return ret;

 		ret = kexec_purgatory_get_set_symbol(image,
 				"purgatory_backup_sz",
 				&image->arch.backup_src_sz,
 				sizeof(image->arch.backup_src_sz), 0);
 		if (ret)
 			return ret;
 	}

 	return ret;
 }
 #else /* !CONFIG_KEXEC_FILE */
 static inline int arch_update_purgatory(struct kimage *image)
 {
 	return 0;
 }
 #endif /* CONFIG_KEXEC_FILE */

 int machine_kexec_prepare(struct kimage *image)
 {
 	unsigned long start_pgtable;
 	int result;

 	/* Calculate the offsets */
 	start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;

 	/* Setup the identity mapped 64bit page table */
 	result = init_pgtable(image, start_pgtable);
 	if (result)
 		return result;

 	/* update purgatory as needed */
 	result = arch_update_purgatory(image);
 	if (result)
 		return result;

 	return 0;
 }

 void machine_kexec_cleanup(struct kimage *image)
 {
 	free_transition_pgtable(image);
 }

 /*
  * Do not allocate memory (or fail in any way) in machine_kexec().
  * We are past the point of no return, committed to rebooting now.
  */
 void machine_kexec(struct kimage *image)
 {
 	unsigned long page_list[PAGES_NR];
 	void *control_page;
 	int save_ftrace_enabled;

 #ifdef CONFIG_KEXEC_JUMP
 	if (image->preserve_context)
 		save_processor_state();
 #endif

 	save_ftrace_enabled = __ftrace_enabled_save();

 	/* Interrupts aren't acceptable while we reboot */
 	local_irq_disable();
 	hw_breakpoint_disable();

 	if (image->preserve_context) {
 #ifdef CONFIG_X86_IO_APIC
 		/*
 		 * We need to put APICs in legacy mode so that we can
 		 * get timer interrupts in second kernel. kexec/kdump
 		 * paths already have calls to restore_boot_irq_mode()
 		 * in one form or other. kexec jump path also need one.
 		 */
 		clear_IO_APIC();
 		restore_boot_irq_mode();
 #endif
 	}

 	control_page = page_address(image->control_code_page) + PAGE_SIZE;
 	memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);

 	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
 	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
 	page_list[PA_TABLE_PAGE] =
 	  (unsigned long)__pa(page_address(image->control_code_page));

 	if (image->type == KEXEC_TYPE_DEFAULT)
 		page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
 						<< PAGE_SHIFT);

 	/*
 	 * The segment registers are funny things, they have both a
 	 * visible and an invisible part.  Whenever the visible part is
 	 * set to a specific selector, the invisible part is loaded
 	 * with from a table in memory.  At no other time is the
 	 * descriptor table in memory accessed.
 	 *
 	 * I take advantage of this here by force loading the
 	 * segments, before I zap the gdt with an invalid value.
 	 */
 	load_segments();
 	/*
 	 * The gdt & idt are now invalid.
 	 * If you want to load them you must set up your own idt & gdt.
 	 */
 	set_gdt(phys_to_virt(0), 0);
 	set_idt(phys_to_virt(0), 0);

 	/* now call it */
 	image->start = relocate_kernel((unsigned long)image->head,
 				       (unsigned long)page_list,
 				       image->start,
 				       image->preserve_context,
 				       sme_active());

 #ifdef CONFIG_KEXEC_JUMP
 	if (image->preserve_context)
 		restore_processor_state();
 #endif

 	__ftrace_enabled_restore(save_ftrace_enabled);
 }

 void arch_crash_save_vmcoreinfo(void)
 {
 	u64 sme_mask = sme_me_mask;

 	VMCOREINFO_NUMBER(phys_base);
 	VMCOREINFO_SYMBOL(init_top_pgt);
 	vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
 			pgtable_l5_enabled());

 #ifdef CONFIG_NUMA
 	VMCOREINFO_SYMBOL(node_data);
 	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
 #endif
 	vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
 			      kaslr_offset());
 	VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
 	VMCOREINFO_NUMBER(sme_mask);
 }

 /* arch-dependent functionality related to kexec file-based syscall */

 #ifdef CONFIG_KEXEC_FILE
 void *arch_kexec_kernel_image_load(struct kimage *image)
 {
 	vfree(image->arch.elf_headers);
 	image->arch.elf_headers = NULL;

 	if (!image->fops || !image->fops->load)
 		return ERR_PTR(-ENOEXEC);

 	return image->fops->load(image, image->kernel_buf,
 				 image->kernel_buf_len, image->initrd_buf,
 				 image->initrd_buf_len, image->cmdline_buf,
 				 image->cmdline_buf_len);
 }

 /*
  * Apply purgatory relocations.
  *
  * @pi:		Purgatory to be relocated.
  * @section:	Section relocations applying to.
  * @relsec:	Section containing RELAs.
  * @symtabsec:	Corresponding symtab.
  *
  * TODO: Some of the code belongs to generic code. Move that in kexec.c.
  */
 int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
 				     Elf_Shdr *section, const Elf_Shdr *relsec,
 				     const Elf_Shdr *symtabsec)
 {
 	unsigned int i;
 	Elf64_Rela *rel;
 	Elf64_Sym *sym;
 	void *location;
 	unsigned long address, sec_base, value;
 	const char *strtab, *name, *shstrtab;
 	const Elf_Shdr *sechdrs;

 	/* String & section header string table */
 	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
 	strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset;
 	shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;

 	rel = (void *)pi->ehdr + relsec->sh_offset;

 	pr_debug("Applying relocate section %s to %u\n",
 		 shstrtab + relsec->sh_name, relsec->sh_info);

 	for (i = 0; i < relsec->sh_size / sizeof(*rel); i++) {

 		/*
 		 * rel[i].r_offset contains byte offset from beginning
 		 * of section to the storage unit affected.
 		 *
 		 * This is location to update. This is temporary buffer
 		 * where section is currently loaded. This will finally be
 		 * loaded to a different address later, pointed to by
 		 * ->sh_addr. kexec takes care of moving it
 		 *  (kexec_load_segment()).
 		 */
 		location = pi->purgatory_buf;
 		location += section->sh_offset;
 		location += rel[i].r_offset;

 		/* Final address of the location */
 		address = section->sh_addr + rel[i].r_offset;

 		/*
 		 * rel[i].r_info contains information about symbol table index
 		 * w.r.t which relocation must be made and type of relocation
 		 * to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
 		 * these respectively.
 		 */
 		sym = (void *)pi->ehdr + symtabsec->sh_offset;
 		sym += ELF64_R_SYM(rel[i].r_info);

 		if (sym->st_name)
 			name = strtab + sym->st_name;
 		else
 			name = shstrtab + sechdrs[sym->st_shndx].sh_name;

 		pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
 			 name, sym->st_info, sym->st_shndx, sym->st_value,
 			 sym->st_size);

 		if (sym->st_shndx == SHN_UNDEF) {
 			pr_err("Undefined symbol: %s\n", name);
 			return -ENOEXEC;
 		}

 		if (sym->st_shndx == SHN_COMMON) {
 			pr_err("symbol '%s' in common section\n", name);
 			return -ENOEXEC;
 		}

 		if (sym->st_shndx == SHN_ABS)
 			sec_base = 0;
 		else if (sym->st_shndx >= pi->ehdr->e_shnum) {
 			pr_err("Invalid section %d for symbol %s\n",
 			       sym->st_shndx, name);
 			return -ENOEXEC;
 		} else
 			sec_base = pi->sechdrs[sym->st_shndx].sh_addr;

 		value = sym->st_value;
 		value += sec_base;
 		value += rel[i].r_addend;

 		switch (ELF64_R_TYPE(rel[i].r_info)) {
 		case R_X86_64_NONE:
 			break;
 		case R_X86_64_64:
 			*(u64 *)location = value;
 			break;
 		case R_X86_64_32:
 			*(u32 *)location = value;
 			if (value != *(u32 *)location)
 				goto overflow;
 			break;
 		case R_X86_64_32S:
 			*(s32 *)location = value;
 			if ((s64)value != *(s32 *)location)
 				goto overflow;
 			break;
 		case R_X86_64_PC32:
 		case R_X86_64_PLT32:
 			value -= (u64)address;
 			*(u32 *)location = value;
 			break;
 		default:
 			pr_err("Unknown rela relocation: %llu\n",
 			       ELF64_R_TYPE(rel[i].r_info));
 			return -ENOEXEC;
 		}
 	}
 	return 0;

 overflow:
 	pr_err("Overflow in relocation type %d value 0x%lx\n",
 	       (int)ELF64_R_TYPE(rel[i].r_info), value);
 	return -ENOEXEC;
 }
 #endif /* CONFIG_KEXEC_FILE */

 static int
 kexec_mark_range(unsigned long start, unsigned long end, bool protect)
 {
 	struct page *page;
 	unsigned int nr_pages;

 	/*
 	 * For physical range: [start, end]. We must skip the unassigned
 	 * crashk resource with zero-valued "end" member.
 	 */
 	if (!end || start > end)
 		return 0;

 	page = pfn_to_page(start >> PAGE_SHIFT);
 	nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
 	if (protect)
 		return set_pages_ro(page, nr_pages);
 	else
 		return set_pages_rw(page, nr_pages);
 }

 static void kexec_mark_crashkres(bool protect)
 {
 	unsigned long control;

 	kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);

 	/* Don't touch the control code page used in crash_kexec().*/
 	control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
 	/* Control code page is located in the 2nd page. */
 	kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
 	control += KEXEC_CONTROL_PAGE_SIZE;
 	kexec_mark_range(control, crashk_res.end, protect);
 }

 void arch_kexec_protect_crashkres(void)
 {
 	kexec_mark_crashkres(true);
 }

 void arch_kexec_unprotect_crashkres(void)
 {
 	kexec_mark_crashkres(false);
 }

 /*
  * During a traditional boot under SME, SME will encrypt the kernel,
  * so the SME kexec kernel also needs to be un-encrypted in order to
  * replicate a normal SME boot.
  *
  * During a traditional boot under SEV, the kernel has already been
  * loaded encrypted, so the SEV kexec kernel needs to be encrypted in
  * order to replicate a normal SEV boot.
  */
 int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
 {
 	if (sev_active())
 		return 0;

 	/*
 	 * If SME is active we need to be sure that kexec pages are
 	 * not encrypted because when we boot to the new kernel the
 	 * pages won't be accessed encrypted (initially).
 	 */
 	return set_memory_decrypted((unsigned long)vaddr, pages);
 }

 void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
 {
 	if (sev_active())
 		return;

 	/*
 	 * If SME is active we need to reset the pages back to being
 	 * an encrypted mapping before freeing them.
 	 */
 	set_memory_encrypted((unsigned long)vaddr, pages);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* handle transition of Linux booting another kernel
	* Copyright (C) 2002-2005 Eric Biederman <ebiederm@xmission.com>
	*/

	#define pr_fmt(fmt) "kexec: " fmt

	#include <linux/mm.h>
	#include <linux/kexec.h>
	#include <linux/string.h>
	#include <linux/gfp.h>
	#include <linux/reboot.h>
	#include <linux/numa.h>
	#include <linux/ftrace.h>
	#include <linux/io.h>
	#include <linux/suspend.h>
	#include <linux/vmalloc.h>
	#include <linux/efi.h>

	#include <asm/init.h>
	#include <asm/pgtable.h>
	#include <asm/tlbflush.h>
	#include <asm/mmu_context.h>
	#include <asm/io_apic.h>
	#include <asm/debugreg.h>
	#include <asm/kexec-bzimage64.h>
	#include <asm/setup.h>
	#include <asm/set_memory.h>

	#ifdef CONFIG_ACPI
	/*
	* Used while adding mapping for ACPI tables.
	* Can be reused when other iomem regions need be mapped
	*/
	struct init_pgtable_data {
	struct x86_mapping_info *info;
	pgd_t *level4p;
	};

	static int mem_region_callback(struct resource res, void arg)
	{
	struct init_pgtable_data *data = arg;
	unsigned long mstart, mend;

	mstart = res->start;
	mend = mstart + resource_size(res) - 1;

	return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend);
	}

	static int
	map_acpi_tables(struct x86_mapping_info info, pgd_t level4p)
	{
	struct init_pgtable_data data;
	unsigned long flags;
	int ret;

	data.info = info;
	data.level4p = level4p;
	flags = IORESOURCE_MEM \| IORESOURCE_BUSY;

	ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1,
	&data, mem_region_callback);
	if (ret && ret != -EINVAL)
	return ret;

	/* ACPI tables could be located in ACPI Non-volatile Storage region */
	ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1,
	&data, mem_region_callback);
	if (ret && ret != -EINVAL)
	return ret;

	return 0;
	}
	#else
	static int map_acpi_tables(struct x86_mapping_info info, pgd_t level4p) { return 0; }
	#endif

	#ifdef CONFIG_KEXEC_FILE
	const struct kexec_file_ops * const kexec_file_loaders[] = {
	&kexec_bzImage64_ops,
	NULL
	};
	#endif

	static int
	map_efi_systab(struct x86_mapping_info info, pgd_t level4p)
	{
	#ifdef CONFIG_EFI
	unsigned long mstart, mend;

	if (!efi_enabled(EFI_BOOT))
	return 0;

	mstart = (boot_params.efi_info.efi_systab \|
	((u64)boot_params.efi_info.efi_systab_hi<<32));

	if (efi_enabled(EFI_64BIT))
	mend = mstart + sizeof(efi_system_table_64_t);
	else
	mend = mstart + sizeof(efi_system_table_32_t);

	if (!mstart)
	return 0;

	return kernel_ident_mapping_init(info, level4p, mstart, mend);
	#endif
	return 0;
	}

	static void free_transition_pgtable(struct kimage *image)
	{
	free_page((unsigned long)image->arch.p4d);
	image->arch.p4d = NULL;
	free_page((unsigned long)image->arch.pud);
	image->arch.pud = NULL;
	free_page((unsigned long)image->arch.pmd);
	image->arch.pmd = NULL;
	free_page((unsigned long)image->arch.pte);
	image->arch.pte = NULL;
	}

	static int init_transition_pgtable(struct kimage image, pgd_t pgd)
	{
	pgprot_t prot = PAGE_KERNEL_EXEC_NOENC;
	unsigned long vaddr, paddr;
	int result = -ENOMEM;
	p4d_t *p4d;
	pud_t *pud;
	pmd_t *pmd;
	pte_t *pte;

	vaddr = (unsigned long)relocate_kernel;
	paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
	pgd += pgd_index(vaddr);
	if (!pgd_present(*pgd)) {
	p4d = (p4d_t *)get_zeroed_page(GFP_KERNEL);
	if (!p4d)
	goto err;
	image->arch.p4d = p4d;
	set_pgd(pgd, __pgd(__pa(p4d) \| _KERNPG_TABLE));
	}
	p4d = p4d_offset(pgd, vaddr);
	if (!p4d_present(*p4d)) {
	pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
	if (!pud)
	goto err;
	image->arch.pud = pud;
	set_p4d(p4d, __p4d(__pa(pud) \| _KERNPG_TABLE));
	}
	pud = pud_offset(p4d, vaddr);
	if (!pud_present(*pud)) {
	pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
	if (!pmd)
	goto err;
	image->arch.pmd = pmd;
	set_pud(pud, __pud(__pa(pmd) \| _KERNPG_TABLE));
	}
	pmd = pmd_offset(pud, vaddr);
	if (!pmd_present(*pmd)) {
	pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
	if (!pte)
	goto err;
	image->arch.pte = pte;
	set_pmd(pmd, __pmd(__pa(pte) \| _KERNPG_TABLE));
	}
	pte = pte_offset_kernel(pmd, vaddr);

	if (sev_active())
	prot = PAGE_KERNEL_EXEC;

	set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, prot));
	return 0;
	err:
	return result;
	}

	static void alloc_pgt_page(void data)
	{
	struct kimage image = (struct kimage )data;
	struct page *page;
	void *p = NULL;

	page = kimage_alloc_control_pages(image, 0);
	if (page) {
	p = page_address(page);
	clear_page(p);
	}

	return p;
	}

	static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
	{
	struct x86_mapping_info info = {
	.alloc_pgt_page = alloc_pgt_page,
	.context = image,
	.page_flag = __PAGE_KERNEL_LARGE_EXEC,
	.kernpg_flag = _KERNPG_TABLE_NOENC,
	};
	unsigned long mstart, mend;
	pgd_t *level4p;
	int result;
	int i;

	level4p = (pgd_t *)__va(start_pgtable);
	clear_page(level4p);

	if (sev_active()) {
	info.page_flag \|= _PAGE_ENC;
	info.kernpg_flag \|= _PAGE_ENC;
	}

	if (direct_gbpages)
	info.direct_gbpages = true;

	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,
	level4p, mstart, mend);
	if (result)
	return result;
	}

	/*
	* segments's mem ranges could be outside 0 ~ max_pfn,
	* for example when jump back to original kernel from kexeced kernel.
	* or first kernel is booted with user mem map, and second kernel
	* could be loaded out of that range.
	*/
	for (i = 0; i < image->nr_segments; i++) {
	mstart = image->segment[i].mem;
	mend = mstart + image->segment[i].memsz;

	result = kernel_ident_mapping_init(&info,
	level4p, mstart, mend);

	if (result)
	return result;
	}

	/*
	* Prepare EFI systab and ACPI tables for kexec kernel since they are
	* not covered by pfn_mapped.
	*/
	result = map_efi_systab(&info, level4p);
	if (result)
	return result;

	result = map_acpi_tables(&info, level4p);
	if (result)
	return result;

	return init_transition_pgtable(image, level4p);
	}

	static void set_idt(void *newidt, u16 limit)
	{
	struct desc_ptr curidt;

	/* x86-64 supports unaliged loads & stores */
	curidt.size = limit;
	curidt.address = (unsigned long)newidt;

	__asm__ __volatile__ (
	"lidtq %0\n"
	: : "m" (curidt)
	);
	};


	static void set_gdt(void *newgdt, u16 limit)
	{
	struct desc_ptr curgdt;

	/* x86-64 supports unaligned loads & stores */
	curgdt.size = limit;
	curgdt.address = (unsigned long)newgdt;

	__asm__ __volatile__ (
	"lgdtq %0\n"
	: : "m" (curgdt)
	);
	};

	static void load_segments(void)
	{
	__asm__ __volatile__ (
	"\tmovl %0,%%ds\n"
	"\tmovl %0,%%es\n"
	"\tmovl %0,%%ss\n"
	"\tmovl %0,%%fs\n"
	"\tmovl %0,%%gs\n"
	: : "a" (__KERNEL_DS) : "memory"
	);
	}

	#ifdef CONFIG_KEXEC_FILE
	/* Update purgatory as needed after various image segments have been prepared */
	static int arch_update_purgatory(struct kimage *image)
	{
	int ret = 0;

	if (!image->file_mode)
	return 0;

	/* Setup copying of backup region */
	if (image->type == KEXEC_TYPE_CRASH) {
	ret = kexec_purgatory_get_set_symbol(image,
	"purgatory_backup_dest",
	&image->arch.backup_load_addr,
	sizeof(image->arch.backup_load_addr), 0);
	if (ret)
	return ret;

	ret = kexec_purgatory_get_set_symbol(image,
	"purgatory_backup_src",
	&image->arch.backup_src_start,
	sizeof(image->arch.backup_src_start), 0);
	if (ret)
	return ret;

	ret = kexec_purgatory_get_set_symbol(image,
	"purgatory_backup_sz",
	&image->arch.backup_src_sz,
	sizeof(image->arch.backup_src_sz), 0);
	if (ret)
	return ret;
	}

	return ret;
	}
	#else /* !CONFIG_KEXEC_FILE */
	static inline int arch_update_purgatory(struct kimage *image)
	{
	return 0;
	}
	#endif /* CONFIG_KEXEC_FILE */

	int machine_kexec_prepare(struct kimage *image)
	{
	unsigned long start_pgtable;
	int result;

	/* Calculate the offsets */
	start_pgtable = page_to_pfn(image->control_code_page) << PAGE_SHIFT;

	/* Setup the identity mapped 64bit page table */
	result = init_pgtable(image, start_pgtable);
	if (result)
	return result;

	/* update purgatory as needed */
	result = arch_update_purgatory(image);
	if (result)
	return result;

	return 0;
	}

	void machine_kexec_cleanup(struct kimage *image)
	{
	free_transition_pgtable(image);
	}

	/*
	* Do not allocate memory (or fail in any way) in machine_kexec().
	* We are past the point of no return, committed to rebooting now.
	*/
	void machine_kexec(struct kimage *image)
	{
	unsigned long page_list[PAGES_NR];
	void *control_page;
	int save_ftrace_enabled;

	#ifdef CONFIG_KEXEC_JUMP
	if (image->preserve_context)
	save_processor_state();
	#endif

	save_ftrace_enabled = __ftrace_enabled_save();

	/* Interrupts aren't acceptable while we reboot */
	local_irq_disable();
	hw_breakpoint_disable();

	if (image->preserve_context) {
	#ifdef CONFIG_X86_IO_APIC
	/*
	* We need to put APICs in legacy mode so that we can
	* get timer interrupts in second kernel. kexec/kdump
	* paths already have calls to restore_boot_irq_mode()
	* in one form or other. kexec jump path also need one.
	*/
	clear_IO_APIC();
	restore_boot_irq_mode();
	#endif
	}

	control_page = page_address(image->control_code_page) + PAGE_SIZE;
	memcpy(control_page, relocate_kernel, KEXEC_CONTROL_CODE_MAX_SIZE);

	page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
	page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
	page_list[PA_TABLE_PAGE] =
	(unsigned long)__pa(page_address(image->control_code_page));

	if (image->type == KEXEC_TYPE_DEFAULT)
	page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
	<< PAGE_SHIFT);

	/*
	* The segment registers are funny things, they have both a
	* visible and an invisible part. Whenever the visible part is
	* set to a specific selector, the invisible part is loaded
	* with from a table in memory. At no other time is the
	* descriptor table in memory accessed.
	*
	* I take advantage of this here by force loading the
	* segments, before I zap the gdt with an invalid value.
	*/
	load_segments();
	/*
	* The gdt & idt are now invalid.
	* If you want to load them you must set up your own idt & gdt.
	*/
	set_gdt(phys_to_virt(0), 0);
	set_idt(phys_to_virt(0), 0);

	/* now call it */
	image->start = relocate_kernel((unsigned long)image->head,
	(unsigned long)page_list,
	image->start,
	image->preserve_context,
	sme_active());

	#ifdef CONFIG_KEXEC_JUMP
	if (image->preserve_context)
	restore_processor_state();
	#endif

	__ftrace_enabled_restore(save_ftrace_enabled);
	}

	void arch_crash_save_vmcoreinfo(void)
	{
	u64 sme_mask = sme_me_mask;

	VMCOREINFO_NUMBER(phys_base);
	VMCOREINFO_SYMBOL(init_top_pgt);
	vmcoreinfo_append_str("NUMBER(pgtable_l5_enabled)=%d\n",
	pgtable_l5_enabled());

	#ifdef CONFIG_NUMA
	VMCOREINFO_SYMBOL(node_data);
	VMCOREINFO_LENGTH(node_data, MAX_NUMNODES);
	#endif
	vmcoreinfo_append_str("KERNELOFFSET=%lx\n",
	kaslr_offset());
	VMCOREINFO_NUMBER(KERNEL_IMAGE_SIZE);
	VMCOREINFO_NUMBER(sme_mask);
	}

	/* arch-dependent functionality related to kexec file-based syscall */

	#ifdef CONFIG_KEXEC_FILE
	void arch_kexec_kernel_image_load(struct kimage image)
	{
	vfree(image->arch.elf_headers);
	image->arch.elf_headers = NULL;

	if (!image->fops \|\| !image->fops->load)
	return ERR_PTR(-ENOEXEC);

	return image->fops->load(image, image->kernel_buf,
	image->kernel_buf_len, image->initrd_buf,
	image->initrd_buf_len, image->cmdline_buf,
	image->cmdline_buf_len);
	}

	/*
	* Apply purgatory relocations.
	*
	* @pi: Purgatory to be relocated.
	* @section: Section relocations applying to.
	* @relsec: Section containing RELAs.
	* @symtabsec: Corresponding symtab.
	*
	* TODO: Some of the code belongs to generic code. Move that in kexec.c.
	*/
	int arch_kexec_apply_relocations_add(struct purgatory_info *pi,
	Elf_Shdr section, const Elf_Shdr relsec,
	const Elf_Shdr *symtabsec)
	{
	unsigned int i;
	Elf64_Rela *rel;
	Elf64_Sym *sym;
	void *location;
	unsigned long address, sec_base, value;
	const char strtab, name, *shstrtab;
	const Elf_Shdr *sechdrs;

	/* String & section header string table */
	sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
	strtab = (char *)pi->ehdr + sechdrs[symtabsec->sh_link].sh_offset;
	shstrtab = (char *)pi->ehdr + sechdrs[pi->ehdr->e_shstrndx].sh_offset;

	rel = (void *)pi->ehdr + relsec->sh_offset;

	pr_debug("Applying relocate section %s to %u\n",
	shstrtab + relsec->sh_name, relsec->sh_info);

	for (i = 0; i < relsec->sh_size / sizeof(*rel); i++) {

	/*
	* rel[i].r_offset contains byte offset from beginning
	* of section to the storage unit affected.
	*
	* This is location to update. This is temporary buffer
	* where section is currently loaded. This will finally be
	* loaded to a different address later, pointed to by
	* ->sh_addr. kexec takes care of moving it
	* (kexec_load_segment()).
	*/
	location = pi->purgatory_buf;
	location += section->sh_offset;
	location += rel[i].r_offset;

	/* Final address of the location */
	address = section->sh_addr + rel[i].r_offset;

	/*
	* rel[i].r_info contains information about symbol table index
	* w.r.t which relocation must be made and type of relocation
	* to apply. ELF64_R_SYM() and ELF64_R_TYPE() macros get
	* these respectively.
	*/
	sym = (void *)pi->ehdr + symtabsec->sh_offset;
	sym += ELF64_R_SYM(rel[i].r_info);

	if (sym->st_name)
	name = strtab + sym->st_name;
	else
	name = shstrtab + sechdrs[sym->st_shndx].sh_name;

	pr_debug("Symbol: %s info: %02x shndx: %02x value=%llx size: %llx\n",
	name, sym->st_info, sym->st_shndx, sym->st_value,
	sym->st_size);

	if (sym->st_shndx == SHN_UNDEF) {
	pr_err("Undefined symbol: %s\n", name);
	return -ENOEXEC;
	}

	if (sym->st_shndx == SHN_COMMON) {
	pr_err("symbol '%s' in common section\n", name);
	return -ENOEXEC;
	}

	if (sym->st_shndx == SHN_ABS)
	sec_base = 0;
	else if (sym->st_shndx >= pi->ehdr->e_shnum) {
	pr_err("Invalid section %d for symbol %s\n",
	sym->st_shndx, name);
	return -ENOEXEC;
	} else
	sec_base = pi->sechdrs[sym->st_shndx].sh_addr;

	value = sym->st_value;
	value += sec_base;
	value += rel[i].r_addend;

	switch (ELF64_R_TYPE(rel[i].r_info)) {
	case R_X86_64_NONE:
	break;
	case R_X86_64_64:
	(u64 )location = value;
	break;
	case R_X86_64_32:
	(u32 )location = value;
	if (value != (u32 )location)
	goto overflow;
	break;
	case R_X86_64_32S:
	(s32 )location = value;
	if ((s64)value != (s32 )location)
	goto overflow;
	break;
	case R_X86_64_PC32:
	case R_X86_64_PLT32:
	value -= (u64)address;
	(u32 )location = value;
	break;
	default:
	pr_err("Unknown rela relocation: %llu\n",
	ELF64_R_TYPE(rel[i].r_info));
	return -ENOEXEC;
	}
	}
	return 0;

	overflow:
	pr_err("Overflow in relocation type %d value 0x%lx\n",
	(int)ELF64_R_TYPE(rel[i].r_info), value);
	return -ENOEXEC;
	}
	#endif /* CONFIG_KEXEC_FILE */

	static int
	kexec_mark_range(unsigned long start, unsigned long end, bool protect)
	{
	struct page *page;
	unsigned int nr_pages;

	/*
	* For physical range: [start, end]. We must skip the unassigned
	* crashk resource with zero-valued "end" member.
	*/
	if (!end \|\| start > end)
	return 0;

	page = pfn_to_page(start >> PAGE_SHIFT);
	nr_pages = (end >> PAGE_SHIFT) - (start >> PAGE_SHIFT) + 1;
	if (protect)
	return set_pages_ro(page, nr_pages);
	else
	return set_pages_rw(page, nr_pages);
	}

	static void kexec_mark_crashkres(bool protect)
	{
	unsigned long control;

	kexec_mark_range(crashk_low_res.start, crashk_low_res.end, protect);

	/* Don't touch the control code page used in crash_kexec().*/
	control = PFN_PHYS(page_to_pfn(kexec_crash_image->control_code_page));
	/* Control code page is located in the 2nd page. */
	kexec_mark_range(crashk_res.start, control + PAGE_SIZE - 1, protect);
	control += KEXEC_CONTROL_PAGE_SIZE;
	kexec_mark_range(control, crashk_res.end, protect);
	}

	void arch_kexec_protect_crashkres(void)
	{
	kexec_mark_crashkres(true);
	}

	void arch_kexec_unprotect_crashkres(void)
	{
	kexec_mark_crashkres(false);
	}

	/*
	* During a traditional boot under SME, SME will encrypt the kernel,
	* so the SME kexec kernel also needs to be un-encrypted in order to
	* replicate a normal SME boot.
	*
	* During a traditional boot under SEV, the kernel has already been
	* loaded encrypted, so the SEV kexec kernel needs to be encrypted in
	* order to replicate a normal SEV boot.
	*/
	int arch_kexec_post_alloc_pages(void *vaddr, unsigned int pages, gfp_t gfp)
	{
	if (sev_active())
	return 0;

	/*
	* If SME is active we need to be sure that kexec pages are
	* not encrypted because when we boot to the new kernel the
	* pages won't be accessed encrypted (initially).
	*/
	return set_memory_decrypted((unsigned long)vaddr, pages);
	}

	void arch_kexec_pre_free_pages(void *vaddr, unsigned int pages)
	{
	if (sev_active())
	return;

	/*
	* If SME is active we need to reset the pages back to being
	* an encrypted mapping before freeing them.
	*/
	set_memory_encrypted((unsigned long)vaddr, pages);
	}