drivers/firmware/efi/libstub/arm-stub.c - third_party/linux - Git at Google

 /*
  * EFI stub implementation that is shared by arm and arm64 architectures.
  * This should be #included by the EFI stub implementation files.
  *
  * Copyright (C) 2013,2014 Linaro Limited
  *     Roy Franz <roy.franz@linaro.org
  * Copyright (C) 2013 Red Hat, Inc.
  *     Mark Salter <msalter@redhat.com>
  *
  * This file is part of the Linux kernel, and is made available under the
  * terms of the GNU General Public License version 2.
  *
  */

 #include <linux/efi.h>
 #include <linux/sort.h>
 #include <asm/efi.h>

 #include "efistub.h"

 static int efi_secureboot_enabled(efi_system_table_t *sys_table_arg)
 {
 	static efi_guid_t const var_guid = EFI_GLOBAL_VARIABLE_GUID;
 	static efi_char16_t const var_name[] = {
 		'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };

 	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
 	unsigned long size = sizeof(u8);
 	efi_status_t status;
 	u8 val;

 	status = f_getvar((efi_char16_t *)var_name, (efi_guid_t *)&var_guid,
 			  NULL, &size, &val);

 	switch (status) {
 	case EFI_SUCCESS:
 		return val;
 	case EFI_NOT_FOUND:
 		return 0;
 	default:
 		return 1;
 	}
 }

 efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
 			     void *__image, void **__fh)
 {
 	efi_file_io_interface_t *io;
 	efi_loaded_image_t *image = __image;
 	efi_file_handle_t *fh;
 	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
 	efi_status_t status;
 	void *handle = (void *)(unsigned long)image->device_handle;

 	status = sys_table_arg->boottime->handle_protocol(handle,
 				 &fs_proto, (void **)&io);
 	if (status != EFI_SUCCESS) {
 		efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
 		return status;
 	}

 	status = io->open_volume(io, &fh);
 	if (status != EFI_SUCCESS)
 		efi_printk(sys_table_arg, "Failed to open volume\n");

 	*__fh = fh;
 	return status;
 }

 efi_status_t efi_file_close(void *handle)
 {
 	efi_file_handle_t *fh = handle;

 	return fh->close(handle);
 }

 efi_status_t
 efi_file_read(void *handle, unsigned long *size, void *addr)
 {
 	efi_file_handle_t *fh = handle;

 	return fh->read(handle, size, addr);
 }


 efi_status_t
 efi_file_size(efi_system_table_t *sys_table_arg, void *__fh,
 	      efi_char16_t *filename_16, void **handle, u64 *file_sz)
 {
 	efi_file_handle_t *h, *fh = __fh;
 	efi_file_info_t *info;
 	efi_status_t status;
 	efi_guid_t info_guid = EFI_FILE_INFO_ID;
 	unsigned long info_sz;

 	status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
 	if (status != EFI_SUCCESS) {
 		efi_printk(sys_table_arg, "Failed to open file: ");
 		efi_char16_printk(sys_table_arg, filename_16);
 		efi_printk(sys_table_arg, "\n");
 		return status;
 	}

 	*handle = h;

 	info_sz = 0;
 	status = h->get_info(h, &info_guid, &info_sz, NULL);
 	if (status != EFI_BUFFER_TOO_SMALL) {
 		efi_printk(sys_table_arg, "Failed to get file info size\n");
 		return status;
 	}

 grow:
 	status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
 				 info_sz, (void **)&info);
 	if (status != EFI_SUCCESS) {
 		efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
 		return status;
 	}

 	status = h->get_info(h, &info_guid, &info_sz,
 						   info);
 	if (status == EFI_BUFFER_TOO_SMALL) {
 		sys_table_arg->boottime->free_pool(info);
 		goto grow;
 	}

 	*file_sz = info->file_size;
 	sys_table_arg->boottime->free_pool(info);

 	if (status != EFI_SUCCESS)
 		efi_printk(sys_table_arg, "Failed to get initrd info\n");

 	return status;
 }


 void efi_char16_printk(efi_system_table_t *sys_table_arg,
 			      efi_char16_t *str)
 {
 	struct efi_simple_text_output_protocol *out;

 	out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
 	out->output_string(out, str);
 }


 /*
  * This function handles the architcture specific differences between arm and
  * arm64 regarding where the kernel image must be loaded and any memory that
  * must be reserved. On failure it is required to free all
  * all allocations it has made.
  */
 efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
 				 unsigned long *image_addr,
 				 unsigned long *image_size,
 				 unsigned long *reserve_addr,
 				 unsigned long *reserve_size,
 				 unsigned long dram_base,
 				 efi_loaded_image_t *image);
 /*
  * EFI entry point for the arm/arm64 EFI stubs.  This is the entrypoint
  * that is described in the PE/COFF header.  Most of the code is the same
  * for both archictectures, with the arch-specific code provided in the
  * handle_kernel_image() function.
  */
 unsigned long efi_entry(void *handle, efi_system_table_t *sys_table,
 			       unsigned long *image_addr)
 {
 	efi_loaded_image_t *image;
 	efi_status_t status;
 	unsigned long image_size = 0;
 	unsigned long dram_base;
 	/* addr/point and size pairs for memory management*/
 	unsigned long initrd_addr;
 	u64 initrd_size = 0;
 	unsigned long fdt_addr = 0;  /* Original DTB */
 	unsigned long fdt_size = 0;
 	char *cmdline_ptr = NULL;
 	int cmdline_size = 0;
 	unsigned long new_fdt_addr;
 	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
 	unsigned long reserve_addr = 0;
 	unsigned long reserve_size = 0;

 	/* Check if we were booted by the EFI firmware */
 	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
 		goto fail;

 	pr_efi(sys_table, "Booting Linux Kernel...\n");

 	/*
 	 * Get a handle to the loaded image protocol.  This is used to get
 	 * information about the running image, such as size and the command
 	 * line.
 	 */
 	status = sys_table->boottime->handle_protocol(handle,
 					&loaded_image_proto, (void *)&image);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
 		goto fail;
 	}

 	dram_base = get_dram_base(sys_table);
 	if (dram_base == EFI_ERROR) {
 		pr_efi_err(sys_table, "Failed to find DRAM base\n");
 		goto fail;
 	}
 	status = handle_kernel_image(sys_table, image_addr, &image_size,
 				     &reserve_addr,
 				     &reserve_size,
 				     dram_base, image);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Failed to relocate kernel\n");
 		goto fail;
 	}

 	/*
 	 * Get the command line from EFI, using the LOADED_IMAGE
 	 * protocol. We are going to copy the command line into the
 	 * device tree, so this can be allocated anywhere.
 	 */
 	cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
 	if (!cmdline_ptr) {
 		pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
 		goto fail_free_image;
 	}

 	status = efi_parse_options(cmdline_ptr);
 	if (status != EFI_SUCCESS)
 		pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");

 	/*
 	 * Unauthenticated device tree data is a security hazard, so
 	 * ignore 'dtb=' unless UEFI Secure Boot is disabled.
 	 */
 	if (efi_secureboot_enabled(sys_table)) {
 		pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
 	} else {
 		status = handle_cmdline_files(sys_table, image, cmdline_ptr,
 					      "dtb=",
 					      ~0UL, &fdt_addr, &fdt_size);

 		if (status != EFI_SUCCESS) {
 			pr_efi_err(sys_table, "Failed to load device tree!\n");
 			goto fail_free_cmdline;
 		}
 	}

 	if (fdt_addr) {
 		pr_efi(sys_table, "Using DTB from command line\n");
 	} else {
 		/* Look for a device tree configuration table entry. */
 		fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
 		if (fdt_addr)
 			pr_efi(sys_table, "Using DTB from configuration table\n");
 	}

 	if (!fdt_addr)
 		pr_efi(sys_table, "Generating empty DTB\n");

 	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
 				      "initrd=", dram_base + SZ_512M,
 				      (unsigned long *)&initrd_addr,
 				      (unsigned long *)&initrd_size);
 	if (status != EFI_SUCCESS)
 		pr_efi_err(sys_table, "Failed initrd from command line!\n");

 	new_fdt_addr = fdt_addr;
 	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
 				&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
 				initrd_addr, initrd_size, cmdline_ptr,
 				fdt_addr, fdt_size);

 	/*
 	 * If all went well, we need to return the FDT address to the
 	 * calling function so it can be passed to kernel as part of
 	 * the kernel boot protocol.
 	 */
 	if (status == EFI_SUCCESS)
 		return new_fdt_addr;

 	pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");

 	efi_free(sys_table, initrd_size, initrd_addr);
 	efi_free(sys_table, fdt_size, fdt_addr);

 fail_free_cmdline:
 	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);

 fail_free_image:
 	efi_free(sys_table, image_size, *image_addr);
 	efi_free(sys_table, reserve_size, reserve_addr);
 fail:
 	return EFI_ERROR;
 }

 /*
  * This is the base address at which to start allocating virtual memory ranges
  * for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
  * any allocation we choose, and eliminate the risk of a conflict after kexec.
  * The value chosen is the largest non-zero power of 2 suitable for this purpose
  * both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
  * be mapped efficiently.
  * Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
  * map everything below 1 GB.
  */
 #define EFI_RT_VIRTUAL_BASE	SZ_512M

 static int cmp_mem_desc(const void *l, const void *r)
 {
 	const efi_memory_desc_t *left = l, *right = r;

 	return (left->phys_addr > right->phys_addr) ? 1 : -1;
 }

 /*
  * Returns whether region @left ends exactly where region @right starts,
  * or false if either argument is NULL.
  */
 static bool regions_are_adjacent(efi_memory_desc_t *left,
 				 efi_memory_desc_t *right)
 {
 	u64 left_end;

 	if (left == NULL || right == NULL)
 		return false;

 	left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;

 	return left_end == right->phys_addr;
 }

 /*
  * Returns whether region @left and region @right have compatible memory type
  * mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
  */
 static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
 						      efi_memory_desc_t *right)
 {
 	static const u64 mem_type_mask = EFI_MEMORY_WB | EFI_MEMORY_WT |
 					 EFI_MEMORY_WC | EFI_MEMORY_UC |
 					 EFI_MEMORY_RUNTIME;

 	return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
 }

 /*
  * efi_get_virtmap() - create a virtual mapping for the EFI memory map
  *
  * This function populates the virt_addr fields of all memory region descriptors
  * in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
  * are also copied to @runtime_map, and their total count is returned in @count.
  */
 void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
 		     unsigned long desc_size, efi_memory_desc_t *runtime_map,
 		     int *count)
 {
 	u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
 	efi_memory_desc_t *in, *prev = NULL, *out = runtime_map;
 	int l;

 	/*
 	 * To work around potential issues with the Properties Table feature
 	 * introduced in UEFI 2.5, which may split PE/COFF executable images
 	 * in memory into several RuntimeServicesCode and RuntimeServicesData
 	 * regions, we need to preserve the relative offsets between adjacent
 	 * EFI_MEMORY_RUNTIME regions with the same memory type attributes.
 	 * The easiest way to find adjacent regions is to sort the memory map
 	 * before traversing it.
 	 */
 	sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);

 	for (l = 0; l < map_size; l += desc_size, prev = in) {
 		u64 paddr, size;

 		in = (void *)memory_map + l;
 		if (!(in->attribute & EFI_MEMORY_RUNTIME))
 			continue;

 		paddr = in->phys_addr;
 		size = in->num_pages * EFI_PAGE_SIZE;

 		/*
 		 * Make the mapping compatible with 64k pages: this allows
 		 * a 4k page size kernel to kexec a 64k page size kernel and
 		 * vice versa.
 		 */
 		if (!regions_are_adjacent(prev, in) ||
 		    !regions_have_compatible_memory_type_attrs(prev, in)) {

 			paddr = round_down(in->phys_addr, SZ_64K);
 			size += in->phys_addr - paddr;

 			/*
 			 * Avoid wasting memory on PTEs by choosing a virtual
 			 * base that is compatible with section mappings if this
 			 * region has the appropriate size and physical
 			 * alignment. (Sections are 2 MB on 4k granule kernels)
 			 */
 			if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
 				efi_virt_base = round_up(efi_virt_base, SZ_2M);
 			else
 				efi_virt_base = round_up(efi_virt_base, SZ_64K);
 		}

 		in->virt_addr = efi_virt_base + in->phys_addr - paddr;
 		efi_virt_base += size;

 		memcpy(out, in, desc_size);
 		out = (void *)out + desc_size;
 		++*count;
 	}
 }
	/*
	* EFI stub implementation that is shared by arm and arm64 architectures.
	* This should be #included by the EFI stub implementation files.
	*
	* Copyright (C) 2013,2014 Linaro Limited
	* Roy Franz <roy.franz@linaro.org
	* Copyright (C) 2013 Red Hat, Inc.
	* Mark Salter <msalter@redhat.com>
	*
	* This file is part of the Linux kernel, and is made available under the
	* terms of the GNU General Public License version 2.
	*
	*/

	#include <linux/efi.h>
	#include <linux/sort.h>
	#include <asm/efi.h>

	#include "efistub.h"

	static int efi_secureboot_enabled(efi_system_table_t *sys_table_arg)
	{
	static efi_guid_t const var_guid = EFI_GLOBAL_VARIABLE_GUID;
	static efi_char16_t const var_name[] = {
	'S', 'e', 'c', 'u', 'r', 'e', 'B', 'o', 'o', 't', 0 };

	efi_get_variable_t *f_getvar = sys_table_arg->runtime->get_variable;
	unsigned long size = sizeof(u8);
	efi_status_t status;
	u8 val;

	status = f_getvar((efi_char16_t )var_name, (efi_guid_t )&var_guid,
	NULL, &size, &val);

	switch (status) {
	case EFI_SUCCESS:
	return val;
	case EFI_NOT_FOUND:
	return 0;
	default:
	return 1;
	}
	}

	efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
	void __image, void *__fh)
	{
	efi_file_io_interface_t *io;
	efi_loaded_image_t *image = __image;
	efi_file_handle_t *fh;
	efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
	efi_status_t status;
	void handle = (void )(unsigned long)image->device_handle;

	status = sys_table_arg->boottime->handle_protocol(handle,
	&fs_proto, (void **)&io);
	if (status != EFI_SUCCESS) {
	efi_printk(sys_table_arg, "Failed to handle fs_proto\n");
	return status;
	}

	status = io->open_volume(io, &fh);
	if (status != EFI_SUCCESS)
	efi_printk(sys_table_arg, "Failed to open volume\n");

	*__fh = fh;
	return status;
	}

	efi_status_t efi_file_close(void *handle)
	{
	efi_file_handle_t *fh = handle;

	return fh->close(handle);
	}

	efi_status_t
	efi_file_read(void handle, unsigned long size, void *addr)
	{
	efi_file_handle_t *fh = handle;

	return fh->read(handle, size, addr);
	}


	efi_status_t
	efi_file_size(efi_system_table_t sys_table_arg, void __fh,
	efi_char16_t filename_16, void handle, u64 file_sz)
	{
	efi_file_handle_t h, fh = __fh;
	efi_file_info_t *info;
	efi_status_t status;
	efi_guid_t info_guid = EFI_FILE_INFO_ID;
	unsigned long info_sz;

	status = fh->open(fh, &h, filename_16, EFI_FILE_MODE_READ, (u64)0);
	if (status != EFI_SUCCESS) {
	efi_printk(sys_table_arg, "Failed to open file: ");
	efi_char16_printk(sys_table_arg, filename_16);
	efi_printk(sys_table_arg, "\n");
	return status;
	}

	*handle = h;

	info_sz = 0;
	status = h->get_info(h, &info_guid, &info_sz, NULL);
	if (status != EFI_BUFFER_TOO_SMALL) {
	efi_printk(sys_table_arg, "Failed to get file info size\n");
	return status;
	}

	grow:
	status = sys_table_arg->boottime->allocate_pool(EFI_LOADER_DATA,
	info_sz, (void **)&info);
	if (status != EFI_SUCCESS) {
	efi_printk(sys_table_arg, "Failed to alloc mem for file info\n");
	return status;
	}

	status = h->get_info(h, &info_guid, &info_sz,
	info);
	if (status == EFI_BUFFER_TOO_SMALL) {
	sys_table_arg->boottime->free_pool(info);
	goto grow;
	}

	*file_sz = info->file_size;
	sys_table_arg->boottime->free_pool(info);

	if (status != EFI_SUCCESS)
	efi_printk(sys_table_arg, "Failed to get initrd info\n");

	return status;
	}



	void efi_char16_printk(efi_system_table_t *sys_table_arg,
	efi_char16_t *str)
	{
	struct efi_simple_text_output_protocol *out;

	out = (struct efi_simple_text_output_protocol *)sys_table_arg->con_out;
	out->output_string(out, str);
	}


	/*
	* This function handles the architcture specific differences between arm and
	* arm64 regarding where the kernel image must be loaded and any memory that
	* must be reserved. On failure it is required to free all
	* all allocations it has made.
	*/
	efi_status_t handle_kernel_image(efi_system_table_t *sys_table,
	unsigned long *image_addr,
	unsigned long *image_size,
	unsigned long *reserve_addr,
	unsigned long *reserve_size,
	unsigned long dram_base,
	efi_loaded_image_t *image);
	/*
	* EFI entry point for the arm/arm64 EFI stubs. This is the entrypoint
	* that is described in the PE/COFF header. Most of the code is the same
	* for both archictectures, with the arch-specific code provided in the
	* handle_kernel_image() function.
	*/
	unsigned long efi_entry(void handle, efi_system_table_t sys_table,
	unsigned long *image_addr)
	{
	efi_loaded_image_t *image;
	efi_status_t status;
	unsigned long image_size = 0;
	unsigned long dram_base;
	/* addr/point and size pairs for memory management*/
	unsigned long initrd_addr;
	u64 initrd_size = 0;
	unsigned long fdt_addr = 0; /* Original DTB */
	unsigned long fdt_size = 0;
	char *cmdline_ptr = NULL;
	int cmdline_size = 0;
	unsigned long new_fdt_addr;
	efi_guid_t loaded_image_proto = LOADED_IMAGE_PROTOCOL_GUID;
	unsigned long reserve_addr = 0;
	unsigned long reserve_size = 0;

	/* Check if we were booted by the EFI firmware */
	if (sys_table->hdr.signature != EFI_SYSTEM_TABLE_SIGNATURE)
	goto fail;

	pr_efi(sys_table, "Booting Linux Kernel...\n");

	/*
	* Get a handle to the loaded image protocol. This is used to get
	* information about the running image, such as size and the command
	* line.
	*/
	status = sys_table->boottime->handle_protocol(handle,
	&loaded_image_proto, (void *)&image);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Failed to get loaded image protocol\n");
	goto fail;
	}

	dram_base = get_dram_base(sys_table);
	if (dram_base == EFI_ERROR) {
	pr_efi_err(sys_table, "Failed to find DRAM base\n");
	goto fail;
	}
	status = handle_kernel_image(sys_table, image_addr, &image_size,
	&reserve_addr,
	&reserve_size,
	dram_base, image);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Failed to relocate kernel\n");
	goto fail;
	}

	/*
	* Get the command line from EFI, using the LOADED_IMAGE
	* protocol. We are going to copy the command line into the
	* device tree, so this can be allocated anywhere.
	*/
	cmdline_ptr = efi_convert_cmdline(sys_table, image, &cmdline_size);
	if (!cmdline_ptr) {
	pr_efi_err(sys_table, "getting command line via LOADED_IMAGE_PROTOCOL\n");
	goto fail_free_image;
	}

	status = efi_parse_options(cmdline_ptr);
	if (status != EFI_SUCCESS)
	pr_efi_err(sys_table, "Failed to parse EFI cmdline options\n");

	/*
	* Unauthenticated device tree data is a security hazard, so
	* ignore 'dtb=' unless UEFI Secure Boot is disabled.
	*/
	if (efi_secureboot_enabled(sys_table)) {
	pr_efi(sys_table, "UEFI Secure Boot is enabled.\n");
	} else {
	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
	"dtb=",
	~0UL, &fdt_addr, &fdt_size);

	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Failed to load device tree!\n");
	goto fail_free_cmdline;
	}
	}

	if (fdt_addr) {
	pr_efi(sys_table, "Using DTB from command line\n");
	} else {
	/* Look for a device tree configuration table entry. */
	fdt_addr = (uintptr_t)get_fdt(sys_table, &fdt_size);
	if (fdt_addr)
	pr_efi(sys_table, "Using DTB from configuration table\n");
	}

	if (!fdt_addr)
	pr_efi(sys_table, "Generating empty DTB\n");

	status = handle_cmdline_files(sys_table, image, cmdline_ptr,
	"initrd=", dram_base + SZ_512M,
	(unsigned long *)&initrd_addr,
	(unsigned long *)&initrd_size);
	if (status != EFI_SUCCESS)
	pr_efi_err(sys_table, "Failed initrd from command line!\n");

	new_fdt_addr = fdt_addr;
	status = allocate_new_fdt_and_exit_boot(sys_table, handle,
	&new_fdt_addr, dram_base + MAX_FDT_OFFSET,
	initrd_addr, initrd_size, cmdline_ptr,
	fdt_addr, fdt_size);

	/*
	* If all went well, we need to return the FDT address to the
	* calling function so it can be passed to kernel as part of
	* the kernel boot protocol.
	*/
	if (status == EFI_SUCCESS)
	return new_fdt_addr;

	pr_efi_err(sys_table, "Failed to update FDT and exit boot services\n");

	efi_free(sys_table, initrd_size, initrd_addr);
	efi_free(sys_table, fdt_size, fdt_addr);

	fail_free_cmdline:
	efi_free(sys_table, cmdline_size, (unsigned long)cmdline_ptr);

	fail_free_image:
	efi_free(sys_table, image_size, *image_addr);
	efi_free(sys_table, reserve_size, reserve_addr);
	fail:
	return EFI_ERROR;
	}

	/*
	* This is the base address at which to start allocating virtual memory ranges
	* for UEFI Runtime Services. This is in the low TTBR0 range so that we can use
	* any allocation we choose, and eliminate the risk of a conflict after kexec.
	* The value chosen is the largest non-zero power of 2 suitable for this purpose
	* both on 32-bit and 64-bit ARM CPUs, to maximize the likelihood that it can
	* be mapped efficiently.
	* Since 32-bit ARM could potentially execute with a 1G/3G user/kernel split,
	* map everything below 1 GB.
	*/
	#define EFI_RT_VIRTUAL_BASE SZ_512M

	static int cmp_mem_desc(const void l, const void r)
	{
	const efi_memory_desc_t left = l, right = r;

	return (left->phys_addr > right->phys_addr) ? 1 : -1;
	}

	/*
	* Returns whether region @left ends exactly where region @right starts,
	* or false if either argument is NULL.
	*/
	static bool regions_are_adjacent(efi_memory_desc_t *left,
	efi_memory_desc_t *right)
	{
	u64 left_end;

	if (left == NULL \|\| right == NULL)
	return false;

	left_end = left->phys_addr + left->num_pages * EFI_PAGE_SIZE;

	return left_end == right->phys_addr;
	}

	/*
	* Returns whether region @left and region @right have compatible memory type
	* mapping attributes, and are both EFI_MEMORY_RUNTIME regions.
	*/
	static bool regions_have_compatible_memory_type_attrs(efi_memory_desc_t *left,
	efi_memory_desc_t *right)
	{
	static const u64 mem_type_mask = EFI_MEMORY_WB \| EFI_MEMORY_WT \|
	EFI_MEMORY_WC \| EFI_MEMORY_UC \|
	EFI_MEMORY_RUNTIME;

	return ((left->attribute ^ right->attribute) & mem_type_mask) == 0;
	}

	/*
	* efi_get_virtmap() - create a virtual mapping for the EFI memory map
	*
	* This function populates the virt_addr fields of all memory region descriptors
	* in @memory_map whose EFI_MEMORY_RUNTIME attribute is set. Those descriptors
	* are also copied to @runtime_map, and their total count is returned in @count.
	*/
	void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
	unsigned long desc_size, efi_memory_desc_t *runtime_map,
	int *count)
	{
	u64 efi_virt_base = EFI_RT_VIRTUAL_BASE;
	efi_memory_desc_t in, prev = NULL, *out = runtime_map;
	int l;

	/*
	* To work around potential issues with the Properties Table feature
	* introduced in UEFI 2.5, which may split PE/COFF executable images
	* in memory into several RuntimeServicesCode and RuntimeServicesData
	* regions, we need to preserve the relative offsets between adjacent
	* EFI_MEMORY_RUNTIME regions with the same memory type attributes.
	* The easiest way to find adjacent regions is to sort the memory map
	* before traversing it.
	*/
	sort(memory_map, map_size / desc_size, desc_size, cmp_mem_desc, NULL);

	for (l = 0; l < map_size; l += desc_size, prev = in) {
	u64 paddr, size;

	in = (void *)memory_map + l;
	if (!(in->attribute & EFI_MEMORY_RUNTIME))
	continue;

	paddr = in->phys_addr;
	size = in->num_pages * EFI_PAGE_SIZE;

	/*
	* Make the mapping compatible with 64k pages: this allows
	* a 4k page size kernel to kexec a 64k page size kernel and
	* vice versa.
	*/
	if (!regions_are_adjacent(prev, in) \|\|
	!regions_have_compatible_memory_type_attrs(prev, in)) {

	paddr = round_down(in->phys_addr, SZ_64K);
	size += in->phys_addr - paddr;

	/*
	* Avoid wasting memory on PTEs by choosing a virtual
	* base that is compatible with section mappings if this
	* region has the appropriate size and physical
	* alignment. (Sections are 2 MB on 4k granule kernels)
	*/
	if (IS_ALIGNED(in->phys_addr, SZ_2M) && size >= SZ_2M)
	efi_virt_base = round_up(efi_virt_base, SZ_2M);
	else
	efi_virt_base = round_up(efi_virt_base, SZ_64K);
	}

	in->virt_addr = efi_virt_base + in->phys_addr - paddr;
	efi_virt_base += size;

	memcpy(out, in, desc_size);
	out = (void *)out + desc_size;
	++*count;
	}
	}