drivers/firmware/efi/libstub/efi-stub-helper.c - LeafOS-Devices/android_kernel_samsung_gta4xl - Gitiles

 /*
  * Helper functions used by the EFI stub on multiple
  * architectures. This should be #included by the EFI stub
  * implementation files.
  *
  * Copyright 2011 Intel Corporation; author Matt Fleming
  *
  * 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 <asm/efi.h>

 #include "efistub.h"

 /*
  * Some firmware implementations have problems reading files in one go.
  * A read chunk size of 1MB seems to work for most platforms.
  *
  * Unfortunately, reading files in chunks triggers *other* bugs on some
  * platforms, so we provide a way to disable this workaround, which can
  * be done by passing "efi=nochunk" on the EFI boot stub command line.
  *
  * If you experience issues with initrd images being corrupt it's worth
  * trying efi=nochunk, but chunking is enabled by default because there
  * are far more machines that require the workaround than those that
  * break with it enabled.
  */
 #define EFI_READ_CHUNK_SIZE	(1024 * 1024)

 static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;

 #define EFI_MMAP_NR_SLACK_SLOTS	8

 struct file_info {
 	efi_file_handle_t *handle;
 	u64 size;
 };

 void efi_printk(efi_system_table_t *sys_table_arg, char *str)
 {
 	char *s8;

 	for (s8 = str; *s8; s8++) {
 		efi_char16_t ch[2] = { 0 };

 		ch[0] = *s8;
 		if (*s8 == '\n') {
 			efi_char16_t nl[2] = { '\r', 0 };
 			efi_char16_printk(sys_table_arg, nl);
 		}

 		efi_char16_printk(sys_table_arg, ch);
 	}
 }

 static inline bool mmap_has_headroom(unsigned long buff_size,
 				     unsigned long map_size,
 				     unsigned long desc_size)
 {
 	unsigned long slack = buff_size - map_size;

 	return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
 }

 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
 				struct efi_boot_memmap *map)
 {
 	efi_memory_desc_t *m = NULL;
 	efi_status_t status;
 	unsigned long key;
 	u32 desc_version;

 	*map->desc_size =	sizeof(*m);
 	*map->map_size =	*map->desc_size * 32;
 	*map->buff_size =	*map->map_size;
 again:
 	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 				*map->map_size, (void **)&m);
 	if (status != EFI_SUCCESS)
 		goto fail;

 	*map->desc_size = 0;
 	key = 0;
 	status = efi_call_early(get_memory_map, map->map_size, m,
 				&key, map->desc_size, &desc_version);
 	if (status == EFI_BUFFER_TOO_SMALL ||
 	    !mmap_has_headroom(*map->buff_size, *map->map_size,
 			       *map->desc_size)) {
 		efi_call_early(free_pool, m);
 		/*
 		 * Make sure there is some entries of headroom so that the
 		 * buffer can be reused for a new map after allocations are
 		 * no longer permitted.  Its unlikely that the map will grow to
 		 * exceed this headroom once we are ready to trigger
 		 * ExitBootServices()
 		 */
 		*map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
 		*map->buff_size = *map->map_size;
 		goto again;
 	}

 	if (status != EFI_SUCCESS)
 		efi_call_early(free_pool, m);

 	if (map->key_ptr && status == EFI_SUCCESS)
 		*map->key_ptr = key;
 	if (map->desc_ver && status == EFI_SUCCESS)
 		*map->desc_ver = desc_version;

 fail:
 	*map->map = m;
 	return status;
 }


 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
 {
 	efi_status_t status;
 	unsigned long map_size, buff_size;
 	unsigned long membase  = EFI_ERROR;
 	struct efi_memory_map map;
 	efi_memory_desc_t *md;
 	struct efi_boot_memmap boot_map;

 	boot_map.map =		(efi_memory_desc_t **)&map.map;
 	boot_map.map_size =	&map_size;
 	boot_map.desc_size =	&map.desc_size;
 	boot_map.desc_ver =	NULL;
 	boot_map.key_ptr =	NULL;
 	boot_map.buff_size =	&buff_size;

 	status = efi_get_memory_map(sys_table_arg, &boot_map);
 	if (status != EFI_SUCCESS)
 		return membase;

 	map.map_end = map.map + map_size;

 	for_each_efi_memory_desc_in_map(&map, md) {
 		if (md->attribute & EFI_MEMORY_WB) {
 			if (membase > md->phys_addr)
 				membase = md->phys_addr;
 		}
 	}

 	efi_call_early(free_pool, map.map);

 	return membase;
 }

 /*
  * Allocate at the highest possible address that is not above 'max'.
  */
 efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
 			    unsigned long size, unsigned long align,
 			    unsigned long *addr, unsigned long max)
 {
 	unsigned long map_size, desc_size, buff_size;
 	efi_memory_desc_t *map;
 	efi_status_t status;
 	unsigned long nr_pages;
 	u64 max_addr = 0;
 	int i;
 	struct efi_boot_memmap boot_map;

 	boot_map.map =		&map;
 	boot_map.map_size =	&map_size;
 	boot_map.desc_size =	&desc_size;
 	boot_map.desc_ver =	NULL;
 	boot_map.key_ptr =	NULL;
 	boot_map.buff_size =	&buff_size;

 	status = efi_get_memory_map(sys_table_arg, &boot_map);
 	if (status != EFI_SUCCESS)
 		goto fail;

 	/*
 	 * Enforce minimum alignment that EFI or Linux requires when
 	 * requesting a specific address.  We are doing page-based (or
 	 * larger) allocations, and both the address and size must meet
 	 * alignment constraints.
 	 */
 	if (align < EFI_ALLOC_ALIGN)
 		align = EFI_ALLOC_ALIGN;

 	size = round_up(size, EFI_ALLOC_ALIGN);
 	nr_pages = size / EFI_PAGE_SIZE;
 again:
 	for (i = 0; i < map_size / desc_size; i++) {
 		efi_memory_desc_t *desc;
 		unsigned long m = (unsigned long)map;
 		u64 start, end;

 		desc = (efi_memory_desc_t *)(m + (i * desc_size));
 		if (desc->type != EFI_CONVENTIONAL_MEMORY)
 			continue;

 		if (desc->num_pages < nr_pages)
 			continue;

 		start = desc->phys_addr;
 		end = start + desc->num_pages * EFI_PAGE_SIZE;

 		if (end > max)
 			end = max;

 		if ((start + size) > end)
 			continue;

 		if (round_down(end - size, align) < start)
 			continue;

 		start = round_down(end - size, align);

 		/*
 		 * Don't allocate at 0x0. It will confuse code that
 		 * checks pointers against NULL.
 		 */
 		if (start == 0x0)
 			continue;

 		if (start > max_addr)
 			max_addr = start;
 	}

 	if (!max_addr)
 		status = EFI_NOT_FOUND;
 	else {
 		status = efi_call_early(allocate_pages,
 					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 					nr_pages, &max_addr);
 		if (status != EFI_SUCCESS) {
 			max = max_addr;
 			max_addr = 0;
 			goto again;
 		}

 		*addr = max_addr;
 	}

 	efi_call_early(free_pool, map);
 fail:
 	return status;
 }

 /*
  * Allocate at the lowest possible address.
  */
 efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
 			   unsigned long size, unsigned long align,
 			   unsigned long *addr)
 {
 	unsigned long map_size, desc_size, buff_size;
 	efi_memory_desc_t *map;
 	efi_status_t status;
 	unsigned long nr_pages;
 	int i;
 	struct efi_boot_memmap boot_map;

 	boot_map.map =		&map;
 	boot_map.map_size =	&map_size;
 	boot_map.desc_size =	&desc_size;
 	boot_map.desc_ver =	NULL;
 	boot_map.key_ptr =	NULL;
 	boot_map.buff_size =	&buff_size;

 	status = efi_get_memory_map(sys_table_arg, &boot_map);
 	if (status != EFI_SUCCESS)
 		goto fail;

 	/*
 	 * Enforce minimum alignment that EFI or Linux requires when
 	 * requesting a specific address.  We are doing page-based (or
 	 * larger) allocations, and both the address and size must meet
 	 * alignment constraints.
 	 */
 	if (align < EFI_ALLOC_ALIGN)
 		align = EFI_ALLOC_ALIGN;

 	size = round_up(size, EFI_ALLOC_ALIGN);
 	nr_pages = size / EFI_PAGE_SIZE;
 	for (i = 0; i < map_size / desc_size; i++) {
 		efi_memory_desc_t *desc;
 		unsigned long m = (unsigned long)map;
 		u64 start, end;

 		desc = (efi_memory_desc_t *)(m + (i * desc_size));

 		if (desc->type != EFI_CONVENTIONAL_MEMORY)
 			continue;

 		if (desc->num_pages < nr_pages)
 			continue;

 		start = desc->phys_addr;
 		end = start + desc->num_pages * EFI_PAGE_SIZE;

 		/*
 		 * Don't allocate at 0x0. It will confuse code that
 		 * checks pointers against NULL. Skip the first 8
 		 * bytes so we start at a nice even number.
 		 */
 		if (start == 0x0)
 			start += 8;

 		start = round_up(start, align);
 		if ((start + size) > end)
 			continue;

 		status = efi_call_early(allocate_pages,
 					EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 					nr_pages, &start);
 		if (status == EFI_SUCCESS) {
 			*addr = start;
 			break;
 		}
 	}

 	if (i == map_size / desc_size)
 		status = EFI_NOT_FOUND;

 	efi_call_early(free_pool, map);
 fail:
 	return status;
 }

 void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
 	      unsigned long addr)
 {
 	unsigned long nr_pages;

 	if (!size)
 		return;

 	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 	efi_call_early(free_pages, addr, nr_pages);
 }

 static 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 = efi_call_proto(efi_file_handle, 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 = efi_call_proto(efi_file_handle, 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 = efi_call_early(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 = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
 				&info_sz, info);
 	if (status == EFI_BUFFER_TOO_SMALL) {
 		efi_call_early(free_pool, info);
 		goto grow;
 	}

 	*file_sz = info->file_size;
 	efi_call_early(free_pool, info);

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

 	return status;
 }

 static efi_status_t efi_file_read(void *handle, unsigned long *size, void *addr)
 {
 	return efi_call_proto(efi_file_handle, read, handle, size, addr);
 }

 static efi_status_t efi_file_close(void *handle)
 {
 	return efi_call_proto(efi_file_handle, close, handle);
 }

 /*
  * Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
  * option, e.g. efi=nochunk.
  *
  * It should be noted that efi= is parsed in two very different
  * environments, first in the early boot environment of the EFI boot
  * stub, and subsequently during the kernel boot.
  */
 efi_status_t efi_parse_options(char *cmdline)
 {
 	char *str;

 	/*
 	 * Currently, the only efi= option we look for is 'nochunk', which
 	 * is intended to work around known issues on certain x86 UEFI
 	 * versions. So ignore for now on other architectures.
 	 */
 	if (!IS_ENABLED(CONFIG_X86))
 		return EFI_SUCCESS;

 	/*
 	 * If no EFI parameters were specified on the cmdline we've got
 	 * nothing to do.
 	 */
 	str = strstr(cmdline, "efi=");
 	if (!str)
 		return EFI_SUCCESS;

 	/* Skip ahead to first argument */
 	str += strlen("efi=");

 	/*
 	 * Remember, because efi= is also used by the kernel we need to
 	 * skip over arguments we don't understand.
 	 */
 	while (*str) {
 		if (!strncmp(str, "nochunk", 7)) {
 			str += strlen("nochunk");
 			__chunk_size = -1UL;
 		}

 		/* Group words together, delimited by "," */
 		while (*str && *str != ',')
 			str++;

 		if (*str == ',')
 			str++;
 	}

 	return EFI_SUCCESS;
 }

 /*
  * Check the cmdline for a LILO-style file= arguments.
  *
  * We only support loading a file from the same filesystem as
  * the kernel image.
  */
 efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
 				  efi_loaded_image_t *image,
 				  char *cmd_line, char *option_string,
 				  unsigned long max_addr,
 				  unsigned long *load_addr,
 				  unsigned long *load_size)
 {
 	struct file_info *files;
 	unsigned long file_addr;
 	u64 file_size_total;
 	efi_file_handle_t *fh = NULL;
 	efi_status_t status;
 	int nr_files;
 	char *str;
 	int i, j, k;

 	file_addr = 0;
 	file_size_total = 0;

 	str = cmd_line;

 	j = 0;			/* See close_handles */

 	if (!load_addr || !load_size)
 		return EFI_INVALID_PARAMETER;

 	*load_addr = 0;
 	*load_size = 0;

 	if (!str || !*str)
 		return EFI_SUCCESS;

 	for (nr_files = 0; *str; nr_files++) {
 		str = strstr(str, option_string);
 		if (!str)
 			break;

 		str += strlen(option_string);

 		/* Skip any leading slashes */
 		while (*str == '/' || *str == '\\')
 			str++;

 		while (*str && *str != ' ' && *str != '\n')
 			str++;
 	}

 	if (!nr_files)
 		return EFI_SUCCESS;

 	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
 				nr_files * sizeof(*files), (void **)&files);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
 		goto fail;
 	}

 	str = cmd_line;
 	for (i = 0; i < nr_files; i++) {
 		struct file_info *file;
 		efi_char16_t filename_16[256];
 		efi_char16_t *p;

 		str = strstr(str, option_string);
 		if (!str)
 			break;

 		str += strlen(option_string);

 		file = &files[i];
 		p = filename_16;

 		/* Skip any leading slashes */
 		while (*str == '/' || *str == '\\')
 			str++;

 		while (*str && *str != ' ' && *str != '\n') {
 			if ((u8 *)p >= (u8 *)filename_16 + sizeof(filename_16))
 				break;

 			if (*str == '/') {
 				*p++ = '\\';
 				str++;
 			} else {
 				*p++ = *str++;
 			}
 		}

 		*p = '\0';

 		/* Only open the volume once. */
 		if (!i) {
 			status = efi_open_volume(sys_table_arg, image,
 						 (void **)&fh);
 			if (status != EFI_SUCCESS)
 				goto free_files;
 		}

 		status = efi_file_size(sys_table_arg, fh, filename_16,
 				       (void **)&file->handle, &file->size);
 		if (status != EFI_SUCCESS)
 			goto close_handles;

 		file_size_total += file->size;
 	}

 	if (file_size_total) {
 		unsigned long addr;

 		/*
 		 * Multiple files need to be at consecutive addresses in memory,
 		 * so allocate enough memory for all the files.  This is used
 		 * for loading multiple files.
 		 */
 		status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
 				    &file_addr, max_addr);
 		if (status != EFI_SUCCESS) {
 			pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
 			goto close_handles;
 		}

 		/* We've run out of free low memory. */
 		if (file_addr > max_addr) {
 			pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
 			status = EFI_INVALID_PARAMETER;
 			goto free_file_total;
 		}

 		addr = file_addr;
 		for (j = 0; j < nr_files; j++) {
 			unsigned long size;

 			size = files[j].size;
 			while (size) {
 				unsigned long chunksize;

 				if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
 					chunksize = __chunk_size;
 				else
 					chunksize = size;

 				status = efi_file_read(files[j].handle,
 						       &chunksize,
 						       (void *)addr);
 				if (status != EFI_SUCCESS) {
 					pr_efi_err(sys_table_arg, "Failed to read file\n");
 					goto free_file_total;
 				}
 				addr += chunksize;
 				size -= chunksize;
 			}

 			efi_file_close(files[j].handle);
 		}

 	}

 	efi_call_early(free_pool, files);

 	*load_addr = file_addr;
 	*load_size = file_size_total;

 	return status;

 free_file_total:
 	efi_free(sys_table_arg, file_size_total, file_addr);

 close_handles:
 	for (k = j; k < i; k++)
 		efi_file_close(files[k].handle);
 free_files:
 	efi_call_early(free_pool, files);
 fail:
 	*load_addr = 0;
 	*load_size = 0;

 	return status;
 }
 /*
  * Relocate a kernel image, either compressed or uncompressed.
  * In the ARM64 case, all kernel images are currently
  * uncompressed, and as such when we relocate it we need to
  * allocate additional space for the BSS segment. Any low
  * memory that this function should avoid needs to be
  * unavailable in the EFI memory map, as if the preferred
  * address is not available the lowest available address will
  * be used.
  */
 efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
 				 unsigned long *image_addr,
 				 unsigned long image_size,
 				 unsigned long alloc_size,
 				 unsigned long preferred_addr,
 				 unsigned long alignment)
 {
 	unsigned long cur_image_addr;
 	unsigned long new_addr = 0;
 	efi_status_t status;
 	unsigned long nr_pages;
 	efi_physical_addr_t efi_addr = preferred_addr;

 	if (!image_addr || !image_size || !alloc_size)
 		return EFI_INVALID_PARAMETER;
 	if (alloc_size < image_size)
 		return EFI_INVALID_PARAMETER;

 	cur_image_addr = *image_addr;

 	/*
 	 * The EFI firmware loader could have placed the kernel image
 	 * anywhere in memory, but the kernel has restrictions on the
 	 * max physical address it can run at.  Some architectures
 	 * also have a prefered address, so first try to relocate
 	 * to the preferred address.  If that fails, allocate as low
 	 * as possible while respecting the required alignment.
 	 */
 	nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
 	status = efi_call_early(allocate_pages,
 				EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
 				nr_pages, &efi_addr);
 	new_addr = efi_addr;
 	/*
 	 * If preferred address allocation failed allocate as low as
 	 * possible.
 	 */
 	if (status != EFI_SUCCESS) {
 		status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
 				       &new_addr);
 	}
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
 		return status;
 	}

 	/*
 	 * We know source/dest won't overlap since both memory ranges
 	 * have been allocated by UEFI, so we can safely use memcpy.
 	 */
 	memcpy((void *)new_addr, (void *)cur_image_addr, image_size);

 	/* Return the new address of the relocated image. */
 	*image_addr = new_addr;

 	return status;
 }

 /*
  * Get the number of UTF-8 bytes corresponding to an UTF-16 character.
  * This overestimates for surrogates, but that is okay.
  */
 static int efi_utf8_bytes(u16 c)
 {
 	return 1 + (c >= 0x80) + (c >= 0x800);
 }

 /*
  * Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
  */
 static u8 *efi_utf16_to_utf8(u8 *dst, const u16 *src, int n)
 {
 	unsigned int c;

 	while (n--) {
 		c = *src++;
 		if (n && c >= 0xd800 && c <= 0xdbff &&
 		    *src >= 0xdc00 && *src <= 0xdfff) {
 			c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
 			src++;
 			n--;
 		}
 		if (c >= 0xd800 && c <= 0xdfff)
 			c = 0xfffd; /* Unmatched surrogate */
 		if (c < 0x80) {
 			*dst++ = c;
 			continue;
 		}
 		if (c < 0x800) {
 			*dst++ = 0xc0 + (c >> 6);
 			goto t1;
 		}
 		if (c < 0x10000) {
 			*dst++ = 0xe0 + (c >> 12);
 			goto t2;
 		}
 		*dst++ = 0xf0 + (c >> 18);
 		*dst++ = 0x80 + ((c >> 12) & 0x3f);
 	t2:
 		*dst++ = 0x80 + ((c >> 6) & 0x3f);
 	t1:
 		*dst++ = 0x80 + (c & 0x3f);
 	}

 	return dst;
 }

 #ifndef MAX_CMDLINE_ADDRESS
 #define MAX_CMDLINE_ADDRESS	ULONG_MAX
 #endif

 /*
  * Convert the unicode UEFI command line to ASCII to pass to kernel.
  * Size of memory allocated return in *cmd_line_len.
  * Returns NULL on error.
  */
 char *efi_convert_cmdline(efi_system_table_t *sys_table_arg,
 			  efi_loaded_image_t *image,
 			  int *cmd_line_len)
 {
 	const u16 *s2;
 	u8 *s1 = NULL;
 	unsigned long cmdline_addr = 0;
 	int load_options_chars = image->load_options_size / 2; /* UTF-16 */
 	const u16 *options = image->load_options;
 	int options_bytes = 0;  /* UTF-8 bytes */
 	int options_chars = 0;  /* UTF-16 chars */
 	efi_status_t status;
 	u16 zero = 0;

 	if (options) {
 		s2 = options;
 		while (*s2 && *s2 != '\n'
 		       && options_chars < load_options_chars) {
 			options_bytes += efi_utf8_bytes(*s2++);
 			options_chars++;
 		}
 	}

 	if (!options_chars) {
 		/* No command line options, so return empty string*/
 		options = &zero;
 	}

 	options_bytes++;	/* NUL termination */

 	status = efi_high_alloc(sys_table_arg, options_bytes, 0,
 				&cmdline_addr, MAX_CMDLINE_ADDRESS);
 	if (status != EFI_SUCCESS)
 		return NULL;

 	s1 = (u8 *)cmdline_addr;
 	s2 = (const u16 *)options;

 	s1 = efi_utf16_to_utf8(s1, s2, options_chars);
 	*s1 = '\0';

 	*cmd_line_len = options_bytes;
 	return (char *)cmdline_addr;
 }

 /*
  * Handle calling ExitBootServices according to the requirements set out by the
  * spec.  Obtains the current memory map, and returns that info after calling
  * ExitBootServices.  The client must specify a function to perform any
  * processing of the memory map data prior to ExitBootServices.  A client
  * specific structure may be passed to the function via priv.  The client
  * function may be called multiple times.
  */
 efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
 				    void *handle,
 				    struct efi_boot_memmap *map,
 				    void *priv,
 				    efi_exit_boot_map_processing priv_func)
 {
 	efi_status_t status;

 	status = efi_get_memory_map(sys_table_arg, map);

 	if (status != EFI_SUCCESS)
 		goto fail;

 	status = priv_func(sys_table_arg, map, priv);
 	if (status != EFI_SUCCESS)
 		goto free_map;

 	status = efi_call_early(exit_boot_services, handle, *map->key_ptr);

 	if (status == EFI_INVALID_PARAMETER) {
 		/*
 		 * The memory map changed between efi_get_memory_map() and
 		 * exit_boot_services().  Per the UEFI Spec v2.6, Section 6.4:
 		 * EFI_BOOT_SERVICES.ExitBootServices we need to get the
 		 * updated map, and try again.  The spec implies one retry
 		 * should be sufficent, which is confirmed against the EDK2
 		 * implementation.  Per the spec, we can only invoke
 		 * get_memory_map() and exit_boot_services() - we cannot alloc
 		 * so efi_get_memory_map() cannot be used, and we must reuse
 		 * the buffer.  For all practical purposes, the headroom in the
 		 * buffer should account for any changes in the map so the call
 		 * to get_memory_map() is expected to succeed here.
 		 */
 		*map->map_size = *map->buff_size;
 		status = efi_call_early(get_memory_map,
 					map->map_size,
 					*map->map,
 					map->key_ptr,
 					map->desc_size,
 					map->desc_ver);

 		/* exit_boot_services() was called, thus cannot free */
 		if (status != EFI_SUCCESS)
 			goto fail;

 		status = priv_func(sys_table_arg, map, priv);
 		/* exit_boot_services() was called, thus cannot free */
 		if (status != EFI_SUCCESS)
 			goto fail;

 		status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
 	}

 	/* exit_boot_services() was called, thus cannot free */
 	if (status != EFI_SUCCESS)
 		goto fail;

 	return EFI_SUCCESS;

 free_map:
 	efi_call_early(free_pool, *map->map);
 fail:
 	return status;
 }
	/*
	* Helper functions used by the EFI stub on multiple
	* architectures. This should be #included by the EFI stub
	* implementation files.
	*
	* Copyright 2011 Intel Corporation; author Matt Fleming
	*
	* 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 <asm/efi.h>

	#include "efistub.h"

	/*
	* Some firmware implementations have problems reading files in one go.
	* A read chunk size of 1MB seems to work for most platforms.
	*
	* Unfortunately, reading files in chunks triggers other bugs on some
	* platforms, so we provide a way to disable this workaround, which can
	* be done by passing "efi=nochunk" on the EFI boot stub command line.
	*
	* If you experience issues with initrd images being corrupt it's worth
	* trying efi=nochunk, but chunking is enabled by default because there
	* are far more machines that require the workaround than those that
	* break with it enabled.
	*/
	#define EFI_READ_CHUNK_SIZE (1024 * 1024)

	static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;

	#define EFI_MMAP_NR_SLACK_SLOTS 8

	struct file_info {
	efi_file_handle_t *handle;
	u64 size;
	};

	void efi_printk(efi_system_table_t sys_table_arg, char str)
	{
	char *s8;

	for (s8 = str; *s8; s8++) {
	efi_char16_t ch[2] = { 0 };

	ch[0] = *s8;
	if (*s8 == '\n') {
	efi_char16_t nl[2] = { '\r', 0 };
	efi_char16_printk(sys_table_arg, nl);
	}

	efi_char16_printk(sys_table_arg, ch);
	}
	}

	static inline bool mmap_has_headroom(unsigned long buff_size,
	unsigned long map_size,
	unsigned long desc_size)
	{
	unsigned long slack = buff_size - map_size;

	return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
	}

	efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
	struct efi_boot_memmap *map)
	{
	efi_memory_desc_t *m = NULL;
	efi_status_t status;
	unsigned long key;
	u32 desc_version;

	map->desc_size = sizeof(m);
	map->map_size = map->desc_size * 32;
	map->buff_size = map->map_size;
	again:
	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
	map->map_size, (void *)&m);
	if (status != EFI_SUCCESS)
	goto fail;

	*map->desc_size = 0;
	key = 0;
	status = efi_call_early(get_memory_map, map->map_size, m,
	&key, map->desc_size, &desc_version);
	if (status == EFI_BUFFER_TOO_SMALL \|\|
	!mmap_has_headroom(map->buff_size, map->map_size,
	*map->desc_size)) {
	efi_call_early(free_pool, m);
	/*
	* Make sure there is some entries of headroom so that the
	* buffer can be reused for a new map after allocations are
	* no longer permitted. Its unlikely that the map will grow to
	* exceed this headroom once we are ready to trigger
	* ExitBootServices()
	*/
	map->map_size += map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
	map->buff_size = map->map_size;
	goto again;
	}

	if (status != EFI_SUCCESS)
	efi_call_early(free_pool, m);

	if (map->key_ptr && status == EFI_SUCCESS)
	*map->key_ptr = key;
	if (map->desc_ver && status == EFI_SUCCESS)
	*map->desc_ver = desc_version;

	fail:
	*map->map = m;
	return status;
	}


	unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
	{
	efi_status_t status;
	unsigned long map_size, buff_size;
	unsigned long membase = EFI_ERROR;
	struct efi_memory_map map;
	efi_memory_desc_t *md;
	struct efi_boot_memmap boot_map;

	boot_map.map = (efi_memory_desc_t **)&map.map;
	boot_map.map_size = &map_size;
	boot_map.desc_size = &map.desc_size;
	boot_map.desc_ver = NULL;
	boot_map.key_ptr = NULL;
	boot_map.buff_size = &buff_size;

	status = efi_get_memory_map(sys_table_arg, &boot_map);
	if (status != EFI_SUCCESS)
	return membase;

	map.map_end = map.map + map_size;

	for_each_efi_memory_desc_in_map(&map, md) {
	if (md->attribute & EFI_MEMORY_WB) {
	if (membase > md->phys_addr)
	membase = md->phys_addr;
	}
	}

	efi_call_early(free_pool, map.map);

	return membase;
	}

	/*
	* Allocate at the highest possible address that is not above 'max'.
	*/
	efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
	unsigned long size, unsigned long align,
	unsigned long *addr, unsigned long max)
	{
	unsigned long map_size, desc_size, buff_size;
	efi_memory_desc_t *map;
	efi_status_t status;
	unsigned long nr_pages;
	u64 max_addr = 0;
	int i;
	struct efi_boot_memmap boot_map;

	boot_map.map = &map;
	boot_map.map_size = &map_size;
	boot_map.desc_size = &desc_size;
	boot_map.desc_ver = NULL;
	boot_map.key_ptr = NULL;
	boot_map.buff_size = &buff_size;

	status = efi_get_memory_map(sys_table_arg, &boot_map);
	if (status != EFI_SUCCESS)
	goto fail;

	/*
	* Enforce minimum alignment that EFI or Linux requires when
	* requesting a specific address. We are doing page-based (or
	* larger) allocations, and both the address and size must meet
	* alignment constraints.
	*/
	if (align < EFI_ALLOC_ALIGN)
	align = EFI_ALLOC_ALIGN;

	size = round_up(size, EFI_ALLOC_ALIGN);
	nr_pages = size / EFI_PAGE_SIZE;
	again:
	for (i = 0; i < map_size / desc_size; i++) {
	efi_memory_desc_t *desc;
	unsigned long m = (unsigned long)map;
	u64 start, end;

	desc = (efi_memory_desc_t )(m + (i desc_size));
	if (desc->type != EFI_CONVENTIONAL_MEMORY)
	continue;

	if (desc->num_pages < nr_pages)
	continue;

	start = desc->phys_addr;
	end = start + desc->num_pages * EFI_PAGE_SIZE;

	if (end > max)
	end = max;

	if ((start + size) > end)
	continue;

	if (round_down(end - size, align) < start)
	continue;

	start = round_down(end - size, align);

	/*
	* Don't allocate at 0x0. It will confuse code that
	* checks pointers against NULL.
	*/
	if (start == 0x0)
	continue;

	if (start > max_addr)
	max_addr = start;
	}

	if (!max_addr)
	status = EFI_NOT_FOUND;
	else {
	status = efi_call_early(allocate_pages,
	EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
	nr_pages, &max_addr);
	if (status != EFI_SUCCESS) {
	max = max_addr;
	max_addr = 0;
	goto again;
	}

	*addr = max_addr;
	}

	efi_call_early(free_pool, map);
	fail:
	return status;
	}

	/*
	* Allocate at the lowest possible address.
	*/
	efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
	unsigned long size, unsigned long align,
	unsigned long *addr)
	{
	unsigned long map_size, desc_size, buff_size;
	efi_memory_desc_t *map;
	efi_status_t status;
	unsigned long nr_pages;
	int i;
	struct efi_boot_memmap boot_map;

	boot_map.map = &map;
	boot_map.map_size = &map_size;
	boot_map.desc_size = &desc_size;
	boot_map.desc_ver = NULL;
	boot_map.key_ptr = NULL;
	boot_map.buff_size = &buff_size;

	status = efi_get_memory_map(sys_table_arg, &boot_map);
	if (status != EFI_SUCCESS)
	goto fail;

	/*
	* Enforce minimum alignment that EFI or Linux requires when
	* requesting a specific address. We are doing page-based (or
	* larger) allocations, and both the address and size must meet
	* alignment constraints.
	*/
	if (align < EFI_ALLOC_ALIGN)
	align = EFI_ALLOC_ALIGN;

	size = round_up(size, EFI_ALLOC_ALIGN);
	nr_pages = size / EFI_PAGE_SIZE;
	for (i = 0; i < map_size / desc_size; i++) {
	efi_memory_desc_t *desc;
	unsigned long m = (unsigned long)map;
	u64 start, end;

	desc = (efi_memory_desc_t )(m + (i desc_size));

	if (desc->type != EFI_CONVENTIONAL_MEMORY)
	continue;

	if (desc->num_pages < nr_pages)
	continue;

	start = desc->phys_addr;
	end = start + desc->num_pages * EFI_PAGE_SIZE;

	/*
	* Don't allocate at 0x0. It will confuse code that
	* checks pointers against NULL. Skip the first 8
	* bytes so we start at a nice even number.
	*/
	if (start == 0x0)
	start += 8;

	start = round_up(start, align);
	if ((start + size) > end)
	continue;

	status = efi_call_early(allocate_pages,
	EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
	nr_pages, &start);
	if (status == EFI_SUCCESS) {
	*addr = start;
	break;
	}
	}

	if (i == map_size / desc_size)
	status = EFI_NOT_FOUND;

	efi_call_early(free_pool, map);
	fail:
	return status;
	}

	void efi_free(efi_system_table_t *sys_table_arg, unsigned long size,
	unsigned long addr)
	{
	unsigned long nr_pages;

	if (!size)
	return;

	nr_pages = round_up(size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
	efi_call_early(free_pages, addr, nr_pages);
	}

	static 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 = efi_call_proto(efi_file_handle, 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 = efi_call_proto(efi_file_handle, 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 = efi_call_early(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 = efi_call_proto(efi_file_handle, get_info, h, &info_guid,
	&info_sz, info);
	if (status == EFI_BUFFER_TOO_SMALL) {
	efi_call_early(free_pool, info);
	goto grow;
	}

	*file_sz = info->file_size;
	efi_call_early(free_pool, info);

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

	return status;
	}

	static efi_status_t efi_file_read(void handle, unsigned long size, void *addr)
	{
	return efi_call_proto(efi_file_handle, read, handle, size, addr);
	}

	static efi_status_t efi_file_close(void *handle)
	{
	return efi_call_proto(efi_file_handle, close, handle);
	}

	/*
	* Parse the ASCII string 'cmdline' for EFI options, denoted by the efi=
	* option, e.g. efi=nochunk.
	*
	* It should be noted that efi= is parsed in two very different
	* environments, first in the early boot environment of the EFI boot
	* stub, and subsequently during the kernel boot.
	*/
	efi_status_t efi_parse_options(char *cmdline)
	{
	char *str;

	/*
	* Currently, the only efi= option we look for is 'nochunk', which
	* is intended to work around known issues on certain x86 UEFI
	* versions. So ignore for now on other architectures.
	*/
	if (!IS_ENABLED(CONFIG_X86))
	return EFI_SUCCESS;

	/*
	* If no EFI parameters were specified on the cmdline we've got
	* nothing to do.
	*/
	str = strstr(cmdline, "efi=");
	if (!str)
	return EFI_SUCCESS;

	/* Skip ahead to first argument */
	str += strlen("efi=");

	/*
	* Remember, because efi= is also used by the kernel we need to
	* skip over arguments we don't understand.
	*/
	while (*str) {
	if (!strncmp(str, "nochunk", 7)) {
	str += strlen("nochunk");
	__chunk_size = -1UL;
	}

	/* Group words together, delimited by "," */
	while (str && str != ',')
	str++;

	if (*str == ',')
	str++;
	}

	return EFI_SUCCESS;
	}

	/*
	* Check the cmdline for a LILO-style file= arguments.
	*
	* We only support loading a file from the same filesystem as
	* the kernel image.
	*/
	efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg,
	efi_loaded_image_t *image,
	char cmd_line, char option_string,
	unsigned long max_addr,
	unsigned long *load_addr,
	unsigned long *load_size)
	{
	struct file_info *files;
	unsigned long file_addr;
	u64 file_size_total;
	efi_file_handle_t *fh = NULL;
	efi_status_t status;
	int nr_files;
	char *str;
	int i, j, k;

	file_addr = 0;
	file_size_total = 0;

	str = cmd_line;

	j = 0; /* See close_handles */

	if (!load_addr \|\| !load_size)
	return EFI_INVALID_PARAMETER;

	*load_addr = 0;
	*load_size = 0;

	if (!str \|\| !*str)
	return EFI_SUCCESS;

	for (nr_files = 0; *str; nr_files++) {
	str = strstr(str, option_string);
	if (!str)
	break;

	str += strlen(option_string);

	/* Skip any leading slashes */
	while (str == '/' \|\| str == '\\')
	str++;

	while (str && str != ' ' && *str != '\n')
	str++;
	}

	if (!nr_files)
	return EFI_SUCCESS;

	status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
	nr_files * sizeof(files), (void *)&files);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table_arg, "Failed to alloc mem for file handle list\n");
	goto fail;
	}

	str = cmd_line;
	for (i = 0; i < nr_files; i++) {
	struct file_info *file;
	efi_char16_t filename_16[256];
	efi_char16_t *p;

	str = strstr(str, option_string);
	if (!str)
	break;

	str += strlen(option_string);

	file = &files[i];
	p = filename_16;

	/* Skip any leading slashes */
	while (str == '/' \|\| str == '\\')
	str++;

	while (str && str != ' ' && *str != '\n') {
	if ((u8 )p >= (u8 )filename_16 + sizeof(filename_16))
	break;

	if (*str == '/') {
	*p++ = '\\';
	str++;
	} else {
	p++ = str++;
	}
	}

	*p = '\0';

	/* Only open the volume once. */
	if (!i) {
	status = efi_open_volume(sys_table_arg, image,
	(void **)&fh);
	if (status != EFI_SUCCESS)
	goto free_files;
	}

	status = efi_file_size(sys_table_arg, fh, filename_16,
	(void **)&file->handle, &file->size);
	if (status != EFI_SUCCESS)
	goto close_handles;

	file_size_total += file->size;
	}

	if (file_size_total) {
	unsigned long addr;

	/*
	* Multiple files need to be at consecutive addresses in memory,
	* so allocate enough memory for all the files. This is used
	* for loading multiple files.
	*/
	status = efi_high_alloc(sys_table_arg, file_size_total, 0x1000,
	&file_addr, max_addr);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table_arg, "Failed to alloc highmem for files\n");
	goto close_handles;
	}

	/* We've run out of free low memory. */
	if (file_addr > max_addr) {
	pr_efi_err(sys_table_arg, "We've run out of free low memory\n");
	status = EFI_INVALID_PARAMETER;
	goto free_file_total;
	}

	addr = file_addr;
	for (j = 0; j < nr_files; j++) {
	unsigned long size;

	size = files[j].size;
	while (size) {
	unsigned long chunksize;

	if (IS_ENABLED(CONFIG_X86) && size > __chunk_size)
	chunksize = __chunk_size;
	else
	chunksize = size;

	status = efi_file_read(files[j].handle,
	&chunksize,
	(void *)addr);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table_arg, "Failed to read file\n");
	goto free_file_total;
	}
	addr += chunksize;
	size -= chunksize;
	}

	efi_file_close(files[j].handle);
	}

	}

	efi_call_early(free_pool, files);

	*load_addr = file_addr;
	*load_size = file_size_total;

	return status;

	free_file_total:
	efi_free(sys_table_arg, file_size_total, file_addr);

	close_handles:
	for (k = j; k < i; k++)
	efi_file_close(files[k].handle);
	free_files:
	efi_call_early(free_pool, files);
	fail:
	*load_addr = 0;
	*load_size = 0;

	return status;
	}
	/*
	* Relocate a kernel image, either compressed or uncompressed.
	* In the ARM64 case, all kernel images are currently
	* uncompressed, and as such when we relocate it we need to
	* allocate additional space for the BSS segment. Any low
	* memory that this function should avoid needs to be
	* unavailable in the EFI memory map, as if the preferred
	* address is not available the lowest available address will
	* be used.
	*/
	efi_status_t efi_relocate_kernel(efi_system_table_t *sys_table_arg,
	unsigned long *image_addr,
	unsigned long image_size,
	unsigned long alloc_size,
	unsigned long preferred_addr,
	unsigned long alignment)
	{
	unsigned long cur_image_addr;
	unsigned long new_addr = 0;
	efi_status_t status;
	unsigned long nr_pages;
	efi_physical_addr_t efi_addr = preferred_addr;

	if (!image_addr \|\| !image_size \|\| !alloc_size)
	return EFI_INVALID_PARAMETER;
	if (alloc_size < image_size)
	return EFI_INVALID_PARAMETER;

	cur_image_addr = *image_addr;

	/*
	* The EFI firmware loader could have placed the kernel image
	* anywhere in memory, but the kernel has restrictions on the
	* max physical address it can run at. Some architectures
	* also have a prefered address, so first try to relocate
	* to the preferred address. If that fails, allocate as low
	* as possible while respecting the required alignment.
	*/
	nr_pages = round_up(alloc_size, EFI_ALLOC_ALIGN) / EFI_PAGE_SIZE;
	status = efi_call_early(allocate_pages,
	EFI_ALLOCATE_ADDRESS, EFI_LOADER_DATA,
	nr_pages, &efi_addr);
	new_addr = efi_addr;
	/*
	* If preferred address allocation failed allocate as low as
	* possible.
	*/
	if (status != EFI_SUCCESS) {
	status = efi_low_alloc(sys_table_arg, alloc_size, alignment,
	&new_addr);
	}
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table_arg, "Failed to allocate usable memory for kernel.\n");
	return status;
	}

	/*
	* We know source/dest won't overlap since both memory ranges
	* have been allocated by UEFI, so we can safely use memcpy.
	*/
	memcpy((void )new_addr, (void )cur_image_addr, image_size);

	/* Return the new address of the relocated image. */
	*image_addr = new_addr;

	return status;
	}

	/*
	* Get the number of UTF-8 bytes corresponding to an UTF-16 character.
	* This overestimates for surrogates, but that is okay.
	*/
	static int efi_utf8_bytes(u16 c)
	{
	return 1 + (c >= 0x80) + (c >= 0x800);
	}

	/*
	* Convert an UTF-16 string, not necessarily null terminated, to UTF-8.
	*/
	static u8 efi_utf16_to_utf8(u8 dst, const u16 *src, int n)
	{
	unsigned int c;

	while (n--) {
	c = *src++;
	if (n && c >= 0xd800 && c <= 0xdbff &&
	src >= 0xdc00 && src <= 0xdfff) {
	c = 0x10000 + ((c & 0x3ff) << 10) + (*src & 0x3ff);
	src++;
	n--;
	}
	if (c >= 0xd800 && c <= 0xdfff)
	c = 0xfffd; /* Unmatched surrogate */
	if (c < 0x80) {
	*dst++ = c;
	continue;
	}
	if (c < 0x800) {
	*dst++ = 0xc0 + (c >> 6);
	goto t1;
	}
	if (c < 0x10000) {
	*dst++ = 0xe0 + (c >> 12);
	goto t2;
	}
	*dst++ = 0xf0 + (c >> 18);
	*dst++ = 0x80 + ((c >> 12) & 0x3f);
	t2:
	*dst++ = 0x80 + ((c >> 6) & 0x3f);
	t1:
	*dst++ = 0x80 + (c & 0x3f);
	}

	return dst;
	}

	#ifndef MAX_CMDLINE_ADDRESS
	#define MAX_CMDLINE_ADDRESS ULONG_MAX
	#endif

	/*
	* Convert the unicode UEFI command line to ASCII to pass to kernel.
	* Size of memory allocated return in *cmd_line_len.
	* Returns NULL on error.
	*/
	char efi_convert_cmdline(efi_system_table_t sys_table_arg,
	efi_loaded_image_t *image,
	int *cmd_line_len)
	{
	const u16 *s2;
	u8 *s1 = NULL;
	unsigned long cmdline_addr = 0;
	int load_options_chars = image->load_options_size / 2; /* UTF-16 */
	const u16 *options = image->load_options;
	int options_bytes = 0; /* UTF-8 bytes */
	int options_chars = 0; /* UTF-16 chars */
	efi_status_t status;
	u16 zero = 0;

	if (options) {
	s2 = options;
	while (s2 && s2 != '\n'
	&& options_chars < load_options_chars) {
	options_bytes += efi_utf8_bytes(*s2++);
	options_chars++;
	}
	}

	if (!options_chars) {
	/* No command line options, so return empty string*/
	options = &zero;
	}

	options_bytes++; /* NUL termination */

	status = efi_high_alloc(sys_table_arg, options_bytes, 0,
	&cmdline_addr, MAX_CMDLINE_ADDRESS);
	if (status != EFI_SUCCESS)
	return NULL;

	s1 = (u8 *)cmdline_addr;
	s2 = (const u16 *)options;

	s1 = efi_utf16_to_utf8(s1, s2, options_chars);
	*s1 = '\0';

	*cmd_line_len = options_bytes;
	return (char *)cmdline_addr;
	}

	/*
	* Handle calling ExitBootServices according to the requirements set out by the
	* spec. Obtains the current memory map, and returns that info after calling
	* ExitBootServices. The client must specify a function to perform any
	* processing of the memory map data prior to ExitBootServices. A client
	* specific structure may be passed to the function via priv. The client
	* function may be called multiple times.
	*/
	efi_status_t efi_exit_boot_services(efi_system_table_t *sys_table_arg,
	void *handle,
	struct efi_boot_memmap *map,
	void *priv,
	efi_exit_boot_map_processing priv_func)
	{
	efi_status_t status;

	status = efi_get_memory_map(sys_table_arg, map);

	if (status != EFI_SUCCESS)
	goto fail;

	status = priv_func(sys_table_arg, map, priv);
	if (status != EFI_SUCCESS)
	goto free_map;

	status = efi_call_early(exit_boot_services, handle, *map->key_ptr);

	if (status == EFI_INVALID_PARAMETER) {
	/*
	* The memory map changed between efi_get_memory_map() and
	* exit_boot_services(). Per the UEFI Spec v2.6, Section 6.4:
	* EFI_BOOT_SERVICES.ExitBootServices we need to get the
	* updated map, and try again. The spec implies one retry
	* should be sufficent, which is confirmed against the EDK2
	* implementation. Per the spec, we can only invoke
	* get_memory_map() and exit_boot_services() - we cannot alloc
	* so efi_get_memory_map() cannot be used, and we must reuse
	* the buffer. For all practical purposes, the headroom in the
	* buffer should account for any changes in the map so the call
	* to get_memory_map() is expected to succeed here.
	*/
	map->map_size = map->buff_size;
	status = efi_call_early(get_memory_map,
	map->map_size,
	*map->map,
	map->key_ptr,
	map->desc_size,
	map->desc_ver);

	/* exit_boot_services() was called, thus cannot free */
	if (status != EFI_SUCCESS)
	goto fail;

	status = priv_func(sys_table_arg, map, priv);
	/* exit_boot_services() was called, thus cannot free */
	if (status != EFI_SUCCESS)
	goto fail;

	status = efi_call_early(exit_boot_services, handle, *map->key_ptr);
	}

	/* exit_boot_services() was called, thus cannot free */
	if (status != EFI_SUCCESS)
	goto fail;

	return EFI_SUCCESS;

	free_map:
	efi_call_early(free_pool, *map->map);
	fail:
	return status;
	}