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

 /*
  * FDT related Helper functions used by the EFI stub on multiple
  * architectures. This should be #included by the EFI stub
  * implementation files.
  *
  * Copyright 2013 Linaro Limited; author Roy Franz
  *
  * 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/libfdt.h>
 #include <asm/efi.h>

 #include "efistub.h"

 #define EFI_DT_ADDR_CELLS_DEFAULT 2
 #define EFI_DT_SIZE_CELLS_DEFAULT 2

 static void fdt_update_cell_size(efi_system_table_t *sys_table, void *fdt)
 {
 	int offset;

 	offset = fdt_path_offset(fdt, "/");
 	/* Set the #address-cells and #size-cells values for an empty tree */

 	fdt_setprop_u32(fdt, offset, "#address-cells",
 			EFI_DT_ADDR_CELLS_DEFAULT);

 	fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT);
 }

 static efi_status_t update_fdt(efi_system_table_t *sys_table, void *orig_fdt,
 			       unsigned long orig_fdt_size,
 			       void *fdt, int new_fdt_size, char *cmdline_ptr,
 			       u64 initrd_addr, u64 initrd_size)
 {
 	int node, num_rsv;
 	int status;
 	u32 fdt_val32;
 	u64 fdt_val64;

 	/* Do some checks on provided FDT, if it exists*/
 	if (orig_fdt) {
 		if (fdt_check_header(orig_fdt)) {
 			pr_efi_err(sys_table, "Device Tree header not valid!\n");
 			return EFI_LOAD_ERROR;
 		}
 		/*
 		 * We don't get the size of the FDT if we get if from a
 		 * configuration table.
 		 */
 		if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
 			pr_efi_err(sys_table, "Truncated device tree! foo!\n");
 			return EFI_LOAD_ERROR;
 		}
 	}

 	if (orig_fdt) {
 		status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
 	} else {
 		status = fdt_create_empty_tree(fdt, new_fdt_size);
 		if (status == 0) {
 			/*
 			 * Any failure from the following function is non
 			 * critical
 			 */
 			fdt_update_cell_size(sys_table, fdt);
 		}
 	}

 	if (status != 0)
 		goto fdt_set_fail;

 	/*
 	 * Delete all memory reserve map entries. When booting via UEFI,
 	 * kernel will use the UEFI memory map to find reserved regions.
 	 */
 	num_rsv = fdt_num_mem_rsv(fdt);
 	while (num_rsv-- > 0)
 		fdt_del_mem_rsv(fdt, num_rsv);

 	node = fdt_subnode_offset(fdt, 0, "chosen");
 	if (node < 0) {
 		node = fdt_add_subnode(fdt, 0, "chosen");
 		if (node < 0) {
 			status = node; /* node is error code when negative */
 			goto fdt_set_fail;
 		}
 	}

 	if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
 		status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
 				     strlen(cmdline_ptr) + 1);
 		if (status)
 			goto fdt_set_fail;
 	}

 	/* Set initrd address/end in device tree, if present */
 	if (initrd_size != 0) {
 		u64 initrd_image_end;
 		u64 initrd_image_start = cpu_to_fdt64(initrd_addr);

 		status = fdt_setprop(fdt, node, "linux,initrd-start",
 				     &initrd_image_start, sizeof(u64));
 		if (status)
 			goto fdt_set_fail;
 		initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
 		status = fdt_setprop(fdt, node, "linux,initrd-end",
 				     &initrd_image_end, sizeof(u64));
 		if (status)
 			goto fdt_set_fail;
 	}

 	/* Add FDT entries for EFI runtime services in chosen node. */
 	node = fdt_subnode_offset(fdt, 0, "chosen");
 	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
 	status = fdt_setprop(fdt, node, "linux,uefi-system-table",
 			     &fdt_val64, sizeof(fdt_val64));
 	if (status)
 		goto fdt_set_fail;

 	fdt_val64 = U64_MAX; /* placeholder */
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
 			     &fdt_val64,  sizeof(fdt_val64));
 	if (status)
 		goto fdt_set_fail;

 	fdt_val32 = U32_MAX; /* placeholder */
 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
 			     &fdt_val32,  sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;

 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
 			     &fdt_val32, sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;

 	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
 			     &fdt_val32, sizeof(fdt_val32));
 	if (status)
 		goto fdt_set_fail;

 	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
 		efi_status_t efi_status;

 		efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64),
 						  (u8 *)&fdt_val64);
 		if (efi_status == EFI_SUCCESS) {
 			status = fdt_setprop(fdt, node, "kaslr-seed",
 					     &fdt_val64, sizeof(fdt_val64));
 			if (status)
 				goto fdt_set_fail;
 		} else if (efi_status != EFI_NOT_FOUND) {
 			return efi_status;
 		}
 	}
 	return EFI_SUCCESS;

 fdt_set_fail:
 	if (status == -FDT_ERR_NOSPACE)
 		return EFI_BUFFER_TOO_SMALL;

 	return EFI_LOAD_ERROR;
 }

 static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
 {
 	int node = fdt_path_offset(fdt, "/chosen");
 	u64 fdt_val64;
 	u32 fdt_val32;
 	int err;

 	if (node < 0)
 		return EFI_LOAD_ERROR;

 	fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
 	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
 				  &fdt_val64, sizeof(fdt_val64));
 	if (err)
 		return EFI_LOAD_ERROR;

 	fdt_val32 = cpu_to_fdt32(*map->map_size);
 	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
 				  &fdt_val32, sizeof(fdt_val32));
 	if (err)
 		return EFI_LOAD_ERROR;

 	fdt_val32 = cpu_to_fdt32(*map->desc_size);
 	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-size",
 				  &fdt_val32, sizeof(fdt_val32));
 	if (err)
 		return EFI_LOAD_ERROR;

 	fdt_val32 = cpu_to_fdt32(*map->desc_ver);
 	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-ver",
 				  &fdt_val32, sizeof(fdt_val32));
 	if (err)
 		return EFI_LOAD_ERROR;

 	return EFI_SUCCESS;
 }

 #ifndef EFI_FDT_ALIGN
 #define EFI_FDT_ALIGN EFI_PAGE_SIZE
 #endif

 struct exit_boot_struct {
 	efi_memory_desc_t *runtime_map;
 	int *runtime_entry_count;
 	void *new_fdt_addr;
 };

 static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg,
 				   struct efi_boot_memmap *map,
 				   void *priv)
 {
 	struct exit_boot_struct *p = priv;
 	/*
 	 * Update the memory map with virtual addresses. The function will also
 	 * populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
 	 * entries so that we can pass it straight to SetVirtualAddressMap()
 	 */
 	efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
 			p->runtime_map, p->runtime_entry_count);

 	return update_fdt_memmap(p->new_fdt_addr, map);
 }

 #ifndef MAX_FDT_SIZE
 #define MAX_FDT_SIZE	SZ_2M
 #endif

 /*
  * Allocate memory for a new FDT, then add EFI, commandline, and
  * initrd related fields to the FDT.  This routine increases the
  * FDT allocation size until the allocated memory is large
  * enough.  EFI allocations are in EFI_PAGE_SIZE granules,
  * which are fixed at 4K bytes, so in most cases the first
  * allocation should succeed.
  * EFI boot services are exited at the end of this function.
  * There must be no allocations between the get_memory_map()
  * call and the exit_boot_services() call, so the exiting of
  * boot services is very tightly tied to the creation of the FDT
  * with the final memory map in it.
  */

 efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
 					    void *handle,
 					    unsigned long *new_fdt_addr,
 					    unsigned long max_addr,
 					    u64 initrd_addr, u64 initrd_size,
 					    char *cmdline_ptr,
 					    unsigned long fdt_addr,
 					    unsigned long fdt_size)
 {
 	unsigned long map_size, desc_size, buff_size;
 	u32 desc_ver;
 	unsigned long mmap_key;
 	efi_memory_desc_t *memory_map, *runtime_map;
 	efi_status_t status;
 	int runtime_entry_count = 0;
 	struct efi_boot_memmap map;
 	struct exit_boot_struct priv;

 	map.map =	&runtime_map;
 	map.map_size =	&map_size;
 	map.desc_size =	&desc_size;
 	map.desc_ver =	&desc_ver;
 	map.key_ptr =	&mmap_key;
 	map.buff_size =	&buff_size;

 	/*
 	 * Get a copy of the current memory map that we will use to prepare
 	 * the input for SetVirtualAddressMap(). We don't have to worry about
 	 * subsequent allocations adding entries, since they could not affect
 	 * the number of EFI_MEMORY_RUNTIME regions.
 	 */
 	status = efi_get_memory_map(sys_table, &map);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
 		return status;
 	}

 	pr_efi(sys_table,
 	       "Exiting boot services and installing virtual address map...\n");

 	map.map = &memory_map;
 	status = efi_high_alloc(sys_table, MAX_FDT_SIZE, EFI_FDT_ALIGN,
 				new_fdt_addr, max_addr);
 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table,
 			   "Unable to allocate memory for new device tree.\n");
 		goto fail;
 	}

 	/*
 	 * Now that we have done our final memory allocation (and free)
 	 * we can get the memory map key needed for exit_boot_services().
 	 */
 	status = efi_get_memory_map(sys_table, &map);
 	if (status != EFI_SUCCESS)
 		goto fail_free_new_fdt;

 	status = update_fdt(sys_table, (void *)fdt_addr, fdt_size,
 			    (void *)*new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
 			    initrd_addr, initrd_size);

 	if (status != EFI_SUCCESS) {
 		pr_efi_err(sys_table, "Unable to construct new device tree.\n");
 		goto fail_free_new_fdt;
 	}

 	priv.runtime_map = runtime_map;
 	priv.runtime_entry_count = &runtime_entry_count;
 	priv.new_fdt_addr = (void *)*new_fdt_addr;
 	status = efi_exit_boot_services(sys_table, handle, &map, &priv,
 					exit_boot_func);

 	if (status == EFI_SUCCESS) {
 		efi_set_virtual_address_map_t *svam;

 		/* Install the new virtual address map */
 		svam = sys_table->runtime->set_virtual_address_map;
 		status = svam(runtime_entry_count * desc_size, desc_size,
 			      desc_ver, runtime_map);

 		/*
 		 * We are beyond the point of no return here, so if the call to
 		 * SetVirtualAddressMap() failed, we need to signal that to the
 		 * incoming kernel but proceed normally otherwise.
 		 */
 		if (status != EFI_SUCCESS) {
 			int l;

 			/*
 			 * Set the virtual address field of all
 			 * EFI_MEMORY_RUNTIME entries to 0. This will signal
 			 * the incoming kernel that no virtual translation has
 			 * been installed.
 			 */
 			for (l = 0; l < map_size; l += desc_size) {
 				efi_memory_desc_t *p = (void *)memory_map + l;

 				if (p->attribute & EFI_MEMORY_RUNTIME)
 					p->virt_addr = 0;
 			}
 		}
 		return EFI_SUCCESS;
 	}

 	pr_efi_err(sys_table, "Exit boot services failed.\n");

 fail_free_new_fdt:
 	efi_free(sys_table, MAX_FDT_SIZE, *new_fdt_addr);

 fail:
 	sys_table->boottime->free_pool(runtime_map);
 	return EFI_LOAD_ERROR;
 }

 void *get_fdt(efi_system_table_t *sys_table, unsigned long *fdt_size)
 {
 	efi_guid_t fdt_guid = DEVICE_TREE_GUID;
 	efi_config_table_t *tables;
 	void *fdt;
 	int i;

 	tables = (efi_config_table_t *) sys_table->tables;
 	fdt = NULL;

 	for (i = 0; i < sys_table->nr_tables; i++)
 		if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
 			fdt = (void *) tables[i].table;
 			if (fdt_check_header(fdt) != 0) {
 				pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
 				return NULL;
 			}
 			*fdt_size = fdt_totalsize(fdt);
 			break;
 	 }

 	return fdt;
 }
	/*
	* FDT related Helper functions used by the EFI stub on multiple
	* architectures. This should be #included by the EFI stub
	* implementation files.
	*
	* Copyright 2013 Linaro Limited; author Roy Franz
	*
	* 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/libfdt.h>
	#include <asm/efi.h>

	#include "efistub.h"

	#define EFI_DT_ADDR_CELLS_DEFAULT 2
	#define EFI_DT_SIZE_CELLS_DEFAULT 2

	static void fdt_update_cell_size(efi_system_table_t sys_table, void fdt)
	{
	int offset;

	offset = fdt_path_offset(fdt, "/");
	/* Set the #address-cells and #size-cells values for an empty tree */

	fdt_setprop_u32(fdt, offset, "#address-cells",
	EFI_DT_ADDR_CELLS_DEFAULT);

	fdt_setprop_u32(fdt, offset, "#size-cells", EFI_DT_SIZE_CELLS_DEFAULT);
	}

	static efi_status_t update_fdt(efi_system_table_t sys_table, void orig_fdt,
	unsigned long orig_fdt_size,
	void fdt, int new_fdt_size, char cmdline_ptr,
	u64 initrd_addr, u64 initrd_size)
	{
	int node, num_rsv;
	int status;
	u32 fdt_val32;
	u64 fdt_val64;

	/* Do some checks on provided FDT, if it exists*/
	if (orig_fdt) {
	if (fdt_check_header(orig_fdt)) {
	pr_efi_err(sys_table, "Device Tree header not valid!\n");
	return EFI_LOAD_ERROR;
	}
	/*
	* We don't get the size of the FDT if we get if from a
	* configuration table.
	*/
	if (orig_fdt_size && fdt_totalsize(orig_fdt) > orig_fdt_size) {
	pr_efi_err(sys_table, "Truncated device tree! foo!\n");
	return EFI_LOAD_ERROR;
	}
	}

	if (orig_fdt) {
	status = fdt_open_into(orig_fdt, fdt, new_fdt_size);
	} else {
	status = fdt_create_empty_tree(fdt, new_fdt_size);
	if (status == 0) {
	/*
	* Any failure from the following function is non
	* critical
	*/
	fdt_update_cell_size(sys_table, fdt);
	}
	}

	if (status != 0)
	goto fdt_set_fail;

	/*
	* Delete all memory reserve map entries. When booting via UEFI,
	* kernel will use the UEFI memory map to find reserved regions.
	*/
	num_rsv = fdt_num_mem_rsv(fdt);
	while (num_rsv-- > 0)
	fdt_del_mem_rsv(fdt, num_rsv);

	node = fdt_subnode_offset(fdt, 0, "chosen");
	if (node < 0) {
	node = fdt_add_subnode(fdt, 0, "chosen");
	if (node < 0) {
	status = node; /* node is error code when negative */
	goto fdt_set_fail;
	}
	}

	if ((cmdline_ptr != NULL) && (strlen(cmdline_ptr) > 0)) {
	status = fdt_setprop(fdt, node, "bootargs", cmdline_ptr,
	strlen(cmdline_ptr) + 1);
	if (status)
	goto fdt_set_fail;
	}

	/* Set initrd address/end in device tree, if present */
	if (initrd_size != 0) {
	u64 initrd_image_end;
	u64 initrd_image_start = cpu_to_fdt64(initrd_addr);

	status = fdt_setprop(fdt, node, "linux,initrd-start",
	&initrd_image_start, sizeof(u64));
	if (status)
	goto fdt_set_fail;
	initrd_image_end = cpu_to_fdt64(initrd_addr + initrd_size);
	status = fdt_setprop(fdt, node, "linux,initrd-end",
	&initrd_image_end, sizeof(u64));
	if (status)
	goto fdt_set_fail;
	}

	/* Add FDT entries for EFI runtime services in chosen node. */
	node = fdt_subnode_offset(fdt, 0, "chosen");
	fdt_val64 = cpu_to_fdt64((u64)(unsigned long)sys_table);
	status = fdt_setprop(fdt, node, "linux,uefi-system-table",
	&fdt_val64, sizeof(fdt_val64));
	if (status)
	goto fdt_set_fail;

	fdt_val64 = U64_MAX; /* placeholder */
	status = fdt_setprop(fdt, node, "linux,uefi-mmap-start",
	&fdt_val64, sizeof(fdt_val64));
	if (status)
	goto fdt_set_fail;

	fdt_val32 = U32_MAX; /* placeholder */
	status = fdt_setprop(fdt, node, "linux,uefi-mmap-size",
	&fdt_val32, sizeof(fdt_val32));
	if (status)
	goto fdt_set_fail;

	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-size",
	&fdt_val32, sizeof(fdt_val32));
	if (status)
	goto fdt_set_fail;

	status = fdt_setprop(fdt, node, "linux,uefi-mmap-desc-ver",
	&fdt_val32, sizeof(fdt_val32));
	if (status)
	goto fdt_set_fail;

	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) {
	efi_status_t efi_status;

	efi_status = efi_get_random_bytes(sys_table, sizeof(fdt_val64),
	(u8 *)&fdt_val64);
	if (efi_status == EFI_SUCCESS) {
	status = fdt_setprop(fdt, node, "kaslr-seed",
	&fdt_val64, sizeof(fdt_val64));
	if (status)
	goto fdt_set_fail;
	} else if (efi_status != EFI_NOT_FOUND) {
	return efi_status;
	}
	}
	return EFI_SUCCESS;

	fdt_set_fail:
	if (status == -FDT_ERR_NOSPACE)
	return EFI_BUFFER_TOO_SMALL;

	return EFI_LOAD_ERROR;
	}

	static efi_status_t update_fdt_memmap(void fdt, struct efi_boot_memmap map)
	{
	int node = fdt_path_offset(fdt, "/chosen");
	u64 fdt_val64;
	u32 fdt_val32;
	int err;

	if (node < 0)
	return EFI_LOAD_ERROR;

	fdt_val64 = cpu_to_fdt64((unsigned long)*map->map);
	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-start",
	&fdt_val64, sizeof(fdt_val64));
	if (err)
	return EFI_LOAD_ERROR;

	fdt_val32 = cpu_to_fdt32(*map->map_size);
	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-size",
	&fdt_val32, sizeof(fdt_val32));
	if (err)
	return EFI_LOAD_ERROR;

	fdt_val32 = cpu_to_fdt32(*map->desc_size);
	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-size",
	&fdt_val32, sizeof(fdt_val32));
	if (err)
	return EFI_LOAD_ERROR;

	fdt_val32 = cpu_to_fdt32(*map->desc_ver);
	err = fdt_setprop_inplace(fdt, node, "linux,uefi-mmap-desc-ver",
	&fdt_val32, sizeof(fdt_val32));
	if (err)
	return EFI_LOAD_ERROR;

	return EFI_SUCCESS;
	}

	#ifndef EFI_FDT_ALIGN
	#define EFI_FDT_ALIGN EFI_PAGE_SIZE
	#endif

	struct exit_boot_struct {
	efi_memory_desc_t *runtime_map;
	int *runtime_entry_count;
	void *new_fdt_addr;
	};

	static efi_status_t exit_boot_func(efi_system_table_t *sys_table_arg,
	struct efi_boot_memmap *map,
	void *priv)
	{
	struct exit_boot_struct *p = priv;
	/*
	* Update the memory map with virtual addresses. The function will also
	* populate @runtime_map with copies of just the EFI_MEMORY_RUNTIME
	* entries so that we can pass it straight to SetVirtualAddressMap()
	*/
	efi_get_virtmap(map->map, map->map_size, *map->desc_size,
	p->runtime_map, p->runtime_entry_count);

	return update_fdt_memmap(p->new_fdt_addr, map);
	}

	#ifndef MAX_FDT_SIZE
	#define MAX_FDT_SIZE SZ_2M
	#endif

	/*
	* Allocate memory for a new FDT, then add EFI, commandline, and
	* initrd related fields to the FDT. This routine increases the
	* FDT allocation size until the allocated memory is large
	* enough. EFI allocations are in EFI_PAGE_SIZE granules,
	* which are fixed at 4K bytes, so in most cases the first
	* allocation should succeed.
	* EFI boot services are exited at the end of this function.
	* There must be no allocations between the get_memory_map()
	* call and the exit_boot_services() call, so the exiting of
	* boot services is very tightly tied to the creation of the FDT
	* with the final memory map in it.
	*/

	efi_status_t allocate_new_fdt_and_exit_boot(efi_system_table_t *sys_table,
	void *handle,
	unsigned long *new_fdt_addr,
	unsigned long max_addr,
	u64 initrd_addr, u64 initrd_size,
	char *cmdline_ptr,
	unsigned long fdt_addr,
	unsigned long fdt_size)
	{
	unsigned long map_size, desc_size, buff_size;
	u32 desc_ver;
	unsigned long mmap_key;
	efi_memory_desc_t memory_map, runtime_map;
	efi_status_t status;
	int runtime_entry_count = 0;
	struct efi_boot_memmap map;
	struct exit_boot_struct priv;

	map.map = &runtime_map;
	map.map_size = &map_size;
	map.desc_size = &desc_size;
	map.desc_ver = &desc_ver;
	map.key_ptr = &mmap_key;
	map.buff_size = &buff_size;

	/*
	* Get a copy of the current memory map that we will use to prepare
	* the input for SetVirtualAddressMap(). We don't have to worry about
	* subsequent allocations adding entries, since they could not affect
	* the number of EFI_MEMORY_RUNTIME regions.
	*/
	status = efi_get_memory_map(sys_table, &map);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Unable to retrieve UEFI memory map.\n");
	return status;
	}

	pr_efi(sys_table,
	"Exiting boot services and installing virtual address map...\n");

	map.map = &memory_map;
	status = efi_high_alloc(sys_table, MAX_FDT_SIZE, EFI_FDT_ALIGN,
	new_fdt_addr, max_addr);
	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table,
	"Unable to allocate memory for new device tree.\n");
	goto fail;
	}

	/*
	* Now that we have done our final memory allocation (and free)
	* we can get the memory map key needed for exit_boot_services().
	*/
	status = efi_get_memory_map(sys_table, &map);
	if (status != EFI_SUCCESS)
	goto fail_free_new_fdt;

	status = update_fdt(sys_table, (void *)fdt_addr, fdt_size,
	(void )new_fdt_addr, MAX_FDT_SIZE, cmdline_ptr,
	initrd_addr, initrd_size);

	if (status != EFI_SUCCESS) {
	pr_efi_err(sys_table, "Unable to construct new device tree.\n");
	goto fail_free_new_fdt;
	}

	priv.runtime_map = runtime_map;
	priv.runtime_entry_count = &runtime_entry_count;
	priv.new_fdt_addr = (void )new_fdt_addr;
	status = efi_exit_boot_services(sys_table, handle, &map, &priv,
	exit_boot_func);

	if (status == EFI_SUCCESS) {
	efi_set_virtual_address_map_t *svam;

	/* Install the new virtual address map */
	svam = sys_table->runtime->set_virtual_address_map;
	status = svam(runtime_entry_count * desc_size, desc_size,
	desc_ver, runtime_map);

	/*
	* We are beyond the point of no return here, so if the call to
	* SetVirtualAddressMap() failed, we need to signal that to the
	* incoming kernel but proceed normally otherwise.
	*/
	if (status != EFI_SUCCESS) {
	int l;

	/*
	* Set the virtual address field of all
	* EFI_MEMORY_RUNTIME entries to 0. This will signal
	* the incoming kernel that no virtual translation has
	* been installed.
	*/
	for (l = 0; l < map_size; l += desc_size) {
	efi_memory_desc_t p = (void )memory_map + l;

	if (p->attribute & EFI_MEMORY_RUNTIME)
	p->virt_addr = 0;
	}
	}
	return EFI_SUCCESS;
	}

	pr_efi_err(sys_table, "Exit boot services failed.\n");

	fail_free_new_fdt:
	efi_free(sys_table, MAX_FDT_SIZE, *new_fdt_addr);

	fail:
	sys_table->boottime->free_pool(runtime_map);
	return EFI_LOAD_ERROR;
	}

	void get_fdt(efi_system_table_t sys_table, unsigned long *fdt_size)
	{
	efi_guid_t fdt_guid = DEVICE_TREE_GUID;
	efi_config_table_t *tables;
	void *fdt;
	int i;

	tables = (efi_config_table_t *) sys_table->tables;
	fdt = NULL;

	for (i = 0; i < sys_table->nr_tables; i++)
	if (efi_guidcmp(tables[i].guid, fdt_guid) == 0) {
	fdt = (void *) tables[i].table;
	if (fdt_check_header(fdt) != 0) {
	pr_efi_err(sys_table, "Invalid header detected on UEFI supplied FDT, ignoring ...\n");
	return NULL;
	}
	*fdt_size = fdt_totalsize(fdt);
	break;
	}

	return fdt;
	}