drivers/of/kexec.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2020 Arm Limited
  *
  * Based on arch/arm64/kernel/machine_kexec_file.c:
  *  Copyright (C) 2018 Linaro Limited
  *
  * And arch/powerpc/kexec/file_load.c:
  *  Copyright (C) 2016  IBM Corporation
  */

 #include <linux/ima.h>
 #include <linux/kernel.h>
 #include <linux/kexec.h>
 #include <linux/memblock.h>
 #include <linux/libfdt.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/types.h>

 #define RNG_SEED_SIZE		128

 /*
  * Additional space needed for the FDT buffer so that we can add initrd,
  * bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr.
  */
 #define FDT_EXTRA_SPACE 0x1000

 /**
  * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
  *
  * @fdt:	Flattened device tree for the current kernel.
  * @start:	Starting address of the reserved memory.
  * @size:	Size of the reserved memory.
  *
  * Return: 0 on success, or negative errno on error.
  */
 static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
 {
 	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);

 	for (i = 0; i < num_rsvs; i++) {
 		u64 rsv_start, rsv_size;

 		ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
 		if (ret) {
 			pr_err("Malformed device tree.\n");
 			return -EINVAL;
 		}

 		if (rsv_start == start && rsv_size == size) {
 			ret = fdt_del_mem_rsv(fdt, i);
 			if (ret) {
 				pr_err("Error deleting device tree reservation.\n");
 				return -EINVAL;
 			}

 			return 0;
 		}
 	}

 	return -ENOENT;
 }

 /**
  * get_addr_size_cells - Get address and size of root node
  *
  * @addr_cells: Return address of the root node
  * @size_cells: Return size of the root node
  *
  * Return: 0 on success, or negative errno on error.
  */
 static int get_addr_size_cells(int *addr_cells, int *size_cells)
 {
 	struct device_node *root;

 	root = of_find_node_by_path("/");
 	if (!root)
 		return -EINVAL;

 	*addr_cells = of_n_addr_cells(root);
 	*size_cells = of_n_size_cells(root);

 	of_node_put(root);

 	return 0;
 }

 /**
  * do_get_kexec_buffer - Get address and size of device tree property
  *
  * @prop: Device tree property
  * @len: Size of @prop
  * @addr: Return address of the node
  * @size: Return size of the node
  *
  * Return: 0 on success, or negative errno on error.
  */
 static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
 			       size_t *size)
 {
 	int ret, addr_cells, size_cells;

 	ret = get_addr_size_cells(&addr_cells, &size_cells);
 	if (ret)
 		return ret;

 	if (len < 4 * (addr_cells + size_cells))
 		return -ENOENT;

 	*addr = of_read_number(prop, addr_cells);
 	*size = of_read_number(prop + 4 * addr_cells, size_cells);

 	return 0;
 }

 #ifdef CONFIG_HAVE_IMA_KEXEC
 /**
  * ima_get_kexec_buffer - get IMA buffer from the previous kernel
  * @addr:	On successful return, set to point to the buffer contents.
  * @size:	On successful return, set to the buffer size.
  *
  * Return: 0 on success, negative errno on error.
  */
 int __init ima_get_kexec_buffer(void **addr, size_t *size)
 {
 	int ret, len;
 	unsigned long tmp_addr;
 	unsigned long start_pfn, end_pfn;
 	size_t tmp_size;
 	const void *prop;

 	prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
 	if (!prop)
 		return -ENOENT;

 	ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
 	if (ret)
 		return ret;

 	/* Do some sanity on the returned size for the ima-kexec buffer */
 	if (!tmp_size)
 		return -ENOENT;

 	/*
 	 * Calculate the PFNs for the buffer and ensure
 	 * they are with in addressable memory.
 	 */
 	start_pfn = PHYS_PFN(tmp_addr);
 	end_pfn = PHYS_PFN(tmp_addr + tmp_size - 1);
 	if (!page_is_ram(start_pfn) || !page_is_ram(end_pfn)) {
 		pr_warn("IMA buffer at 0x%lx, size = 0x%zx beyond memory\n",
 			tmp_addr, tmp_size);
 		return -EINVAL;
 	}

 	*addr = __va(tmp_addr);
 	*size = tmp_size;

 	return 0;
 }

 /**
  * ima_free_kexec_buffer - free memory used by the IMA buffer
  */
 int __init ima_free_kexec_buffer(void)
 {
 	int ret;
 	unsigned long addr;
 	size_t size;
 	struct property *prop;

 	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
 	if (!prop)
 		return -ENOENT;

 	ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
 	if (ret)
 		return ret;

 	ret = of_remove_property(of_chosen, prop);
 	if (ret)
 		return ret;

 	memblock_free_late(addr, size);
 	return 0;
 }
 #endif

 /**
  * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
  *
  * @fdt: Flattened Device Tree to update
  * @chosen_node: Offset to the chosen node in the device tree
  *
  * The IMA measurement buffer is of no use to a subsequent kernel, so we always
  * remove it from the device tree.
  */
 static void remove_ima_buffer(void *fdt, int chosen_node)
 {
 	int ret, len;
 	unsigned long addr;
 	size_t size;
 	const void *prop;

 	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
 		return;

 	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
 	if (!prop)
 		return;

 	ret = do_get_kexec_buffer(prop, len, &addr, &size);
 	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
 	if (ret)
 		return;

 	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
 	if (!ret)
 		pr_debug("Removed old IMA buffer reservation.\n");
 }

 #ifdef CONFIG_IMA_KEXEC
 /**
  * setup_ima_buffer - add IMA buffer information to the fdt
  * @image:		kexec image being loaded.
  * @fdt:		Flattened device tree for the next kernel.
  * @chosen_node:	Offset to the chosen node.
  *
  * Return: 0 on success, or negative errno on error.
  */
 static int setup_ima_buffer(const struct kimage *image, void *fdt,
 			    int chosen_node)
 {
 	int ret;

 	if (!image->ima_buffer_size)
 		return 0;

 	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
 				       "linux,ima-kexec-buffer",
 				       image->ima_buffer_addr,
 				       image->ima_buffer_size);
 	if (ret < 0)
 		return -EINVAL;

 	ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
 			      image->ima_buffer_size);
 	if (ret)
 		return -EINVAL;

 	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
 		 image->ima_buffer_addr, image->ima_buffer_size);

 	return 0;
 }
 #else /* CONFIG_IMA_KEXEC */
 static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
 				   int chosen_node)
 {
 	return 0;
 }
 #endif /* CONFIG_IMA_KEXEC */

 /*
  * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
  *
  * @image:		kexec image being loaded.
  * @initrd_load_addr:	Address where the next initrd will be loaded.
  * @initrd_len:		Size of the next initrd, or 0 if there will be none.
  * @cmdline:		Command line for the next kernel, or NULL if there will
  *			be none.
  * @extra_fdt_size:	Additional size for the new FDT buffer.
  *
  * Return: fdt on success, or NULL errno on error.
  */
 void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 				   unsigned long initrd_load_addr,
 				   unsigned long initrd_len,
 				   const char *cmdline, size_t extra_fdt_size)
 {
 	void *fdt;
 	int ret, chosen_node, len;
 	const void *prop;
 	size_t fdt_size;

 	fdt_size = fdt_totalsize(initial_boot_params) +
 		   (cmdline ? strlen(cmdline) : 0) +
 		   FDT_EXTRA_SPACE +
 		   extra_fdt_size;
 	fdt = kvmalloc(fdt_size, GFP_KERNEL);
 	if (!fdt)
 		return NULL;

 	ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
 	if (ret < 0) {
 		pr_err("Error %d setting up the new device tree.\n", ret);
 		goto out;
 	}

 	/* Remove memory reservation for the current device tree. */
 	ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
 				       fdt_totalsize(initial_boot_params));
 	if (ret == -EINVAL) {
 		pr_err("Error removing memory reservation.\n");
 		goto out;
 	}

 	chosen_node = fdt_path_offset(fdt, "/chosen");
 	if (chosen_node == -FDT_ERR_NOTFOUND)
 		chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
 					      "chosen");
 	if (chosen_node < 0) {
 		ret = chosen_node;
 		goto out;
 	}

 	ret = fdt_delprop(fdt, chosen_node, "linux,elfcorehdr");
 	if (ret && ret != -FDT_ERR_NOTFOUND)
 		goto out;
 	ret = fdt_delprop(fdt, chosen_node, "linux,usable-memory-range");
 	if (ret && ret != -FDT_ERR_NOTFOUND)
 		goto out;

 	/* Did we boot using an initrd? */
 	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", &len);
 	if (prop) {
 		u64 tmp_start, tmp_end, tmp_size;

 		tmp_start = of_read_number(prop, len / 4);

 		prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", &len);
 		if (!prop) {
 			ret = -EINVAL;
 			goto out;
 		}

 		tmp_end = of_read_number(prop, len / 4);

 		/*
 		 * kexec reserves exact initrd size, while firmware may
 		 * reserve a multiple of PAGE_SIZE, so check for both.
 		 */
 		tmp_size = tmp_end - tmp_start;
 		ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size);
 		if (ret == -ENOENT)
 			ret = fdt_find_and_del_mem_rsv(fdt, tmp_start,
 						       round_up(tmp_size, PAGE_SIZE));
 		if (ret == -EINVAL)
 			goto out;
 	}

 	/* add initrd-* */
 	if (initrd_load_addr) {
 		ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-start",
 				      initrd_load_addr);
 		if (ret)
 			goto out;

 		ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
 				      initrd_load_addr + initrd_len);
 		if (ret)
 			goto out;

 		ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
 		if (ret)
 			goto out;

 	} else {
 		ret = fdt_delprop(fdt, chosen_node, "linux,initrd-start");
 		if (ret && (ret != -FDT_ERR_NOTFOUND))
 			goto out;

 		ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
 		if (ret && (ret != -FDT_ERR_NOTFOUND))
 			goto out;
 	}

 	if (image->type == KEXEC_TYPE_CRASH) {
 		/* add linux,elfcorehdr */
 		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
 				"linux,elfcorehdr", image->elf_load_addr,
 				image->elf_headers_sz);
 		if (ret)
 			goto out;

 		/*
 		 * Avoid elfcorehdr from being stomped on in kdump kernel by
 		 * setting up memory reserve map.
 		 */
 		ret = fdt_add_mem_rsv(fdt, image->elf_load_addr,
 				      image->elf_headers_sz);
 		if (ret)
 			goto out;

 #ifdef CONFIG_CRASH_DUMP
 		/* add linux,usable-memory-range */
 		ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
 				"linux,usable-memory-range", crashk_res.start,
 				crashk_res.end - crashk_res.start + 1);
 		if (ret)
 			goto out;

 		if (crashk_low_res.end) {
 			ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
 					"linux,usable-memory-range",
 					crashk_low_res.start,
 					crashk_low_res.end - crashk_low_res.start + 1);
 			if (ret)
 				goto out;
 		}
 #endif
 	}

 	/* add bootargs */
 	if (cmdline) {
 		ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
 		if (ret)
 			goto out;
 	} else {
 		ret = fdt_delprop(fdt, chosen_node, "bootargs");
 		if (ret && (ret != -FDT_ERR_NOTFOUND))
 			goto out;
 	}

 	/* add kaslr-seed */
 	ret = fdt_delprop(fdt, chosen_node, "kaslr-seed");
 	if (ret == -FDT_ERR_NOTFOUND)
 		ret = 0;
 	else if (ret)
 		goto out;

 	if (rng_is_initialized()) {
 		u64 seed = get_random_u64();

 		ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed);
 		if (ret)
 			goto out;
 	} else {
 		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
 			  "kaslr-seed");
 	}

 	/* add rng-seed */
 	if (rng_is_initialized()) {
 		void *rng_seed;

 		ret = fdt_setprop_placeholder(fdt, chosen_node, "rng-seed",
 				RNG_SEED_SIZE, &rng_seed);
 		if (ret)
 			goto out;
 		get_random_bytes(rng_seed, RNG_SEED_SIZE);
 	} else {
 		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
 			  "rng-seed");
 	}

 	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
 	if (ret)
 		goto out;

 	remove_ima_buffer(fdt, chosen_node);
 	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));

 out:
 	if (ret) {
 		kvfree(fdt);
 		fdt = NULL;
 	}

 	return fdt;
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (C) 2020 Arm Limited
	*
	* Based on arch/arm64/kernel/machine_kexec_file.c:
	* Copyright (C) 2018 Linaro Limited
	*
	* And arch/powerpc/kexec/file_load.c:
	* Copyright (C) 2016 IBM Corporation
	*/

	#include <linux/ima.h>
	#include <linux/kernel.h>
	#include <linux/kexec.h>
	#include <linux/memblock.h>
	#include <linux/libfdt.h>
	#include <linux/of.h>
	#include <linux/of_fdt.h>
	#include <linux/random.h>
	#include <linux/slab.h>
	#include <linux/types.h>

	#define RNG_SEED_SIZE 128

	/*
	* Additional space needed for the FDT buffer so that we can add initrd,
	* bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr.
	*/
	#define FDT_EXTRA_SPACE 0x1000

	/**
	* fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
	*
	* @fdt: Flattened device tree for the current kernel.
	* @start: Starting address of the reserved memory.
	* @size: Size of the reserved memory.
	*
	* Return: 0 on success, or negative errno on error.
	*/
	static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
	{
	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);

	for (i = 0; i < num_rsvs; i++) {
	u64 rsv_start, rsv_size;

	ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
	if (ret) {
	pr_err("Malformed device tree.\n");
	return -EINVAL;
	}

	if (rsv_start == start && rsv_size == size) {
	ret = fdt_del_mem_rsv(fdt, i);
	if (ret) {
	pr_err("Error deleting device tree reservation.\n");
	return -EINVAL;
	}

	return 0;
	}
	}

	return -ENOENT;
	}

	/**
	* get_addr_size_cells - Get address and size of root node
	*
	* @addr_cells: Return address of the root node
	* @size_cells: Return size of the root node
	*
	* Return: 0 on success, or negative errno on error.
	*/
	static int get_addr_size_cells(int addr_cells, int size_cells)
	{
	struct device_node *root;

	root = of_find_node_by_path("/");
	if (!root)
	return -EINVAL;

	*addr_cells = of_n_addr_cells(root);
	*size_cells = of_n_size_cells(root);

	of_node_put(root);

	return 0;
	}

	/**
	* do_get_kexec_buffer - Get address and size of device tree property
	*
	* @prop: Device tree property
	* @len: Size of @prop
	* @addr: Return address of the node
	* @size: Return size of the node
	*
	* Return: 0 on success, or negative errno on error.
	*/
	static int do_get_kexec_buffer(const void prop, int len, unsigned long addr,
	size_t *size)
	{
	int ret, addr_cells, size_cells;

	ret = get_addr_size_cells(&addr_cells, &size_cells);
	if (ret)
	return ret;

	if (len < 4 * (addr_cells + size_cells))
	return -ENOENT;

	*addr = of_read_number(prop, addr_cells);
	size = of_read_number(prop + 4 addr_cells, size_cells);

	return 0;
	}

	#ifdef CONFIG_HAVE_IMA_KEXEC
	/**
	* ima_get_kexec_buffer - get IMA buffer from the previous kernel
	* @addr: On successful return, set to point to the buffer contents.
	* @size: On successful return, set to the buffer size.
	*
	* Return: 0 on success, negative errno on error.
	*/
	int __init ima_get_kexec_buffer(void *addr, size_t size)
	{
	int ret, len;
	unsigned long tmp_addr;
	unsigned long start_pfn, end_pfn;
	size_t tmp_size;
	const void *prop;

	prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
	if (!prop)
	return -ENOENT;

	ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
	if (ret)
	return ret;

	/* Do some sanity on the returned size for the ima-kexec buffer */
	if (!tmp_size)
	return -ENOENT;

	/*
	* Calculate the PFNs for the buffer and ensure
	* they are with in addressable memory.
	*/
	start_pfn = PHYS_PFN(tmp_addr);
	end_pfn = PHYS_PFN(tmp_addr + tmp_size - 1);
	if (!page_is_ram(start_pfn) \|\| !page_is_ram(end_pfn)) {
	pr_warn("IMA buffer at 0x%lx, size = 0x%zx beyond memory\n",
	tmp_addr, tmp_size);
	return -EINVAL;
	}

	*addr = __va(tmp_addr);
	*size = tmp_size;

	return 0;
	}

	/**
	* ima_free_kexec_buffer - free memory used by the IMA buffer
	*/
	int __init ima_free_kexec_buffer(void)
	{
	int ret;
	unsigned long addr;
	size_t size;
	struct property *prop;

	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
	if (!prop)
	return -ENOENT;

	ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
	if (ret)
	return ret;

	ret = of_remove_property(of_chosen, prop);
	if (ret)
	return ret;

	memblock_free_late(addr, size);
	return 0;
	}
	#endif

	/**
	* remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
	*
	* @fdt: Flattened Device Tree to update
	* @chosen_node: Offset to the chosen node in the device tree
	*
	* The IMA measurement buffer is of no use to a subsequent kernel, so we always
	* remove it from the device tree.
	*/
	static void remove_ima_buffer(void *fdt, int chosen_node)
	{
	int ret, len;
	unsigned long addr;
	size_t size;
	const void *prop;

	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
	return;

	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
	if (!prop)
	return;

	ret = do_get_kexec_buffer(prop, len, &addr, &size);
	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
	if (ret)
	return;

	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
	if (!ret)
	pr_debug("Removed old IMA buffer reservation.\n");
	}

	#ifdef CONFIG_IMA_KEXEC
	/**
	* setup_ima_buffer - add IMA buffer information to the fdt
	* @image: kexec image being loaded.
	* @fdt: Flattened device tree for the next kernel.
	* @chosen_node: Offset to the chosen node.
	*
	* Return: 0 on success, or negative errno on error.
	*/
	static int setup_ima_buffer(const struct kimage image, void fdt,
	int chosen_node)
	{
	int ret;

	if (!image->ima_buffer_size)
	return 0;

	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
	"linux,ima-kexec-buffer",
	image->ima_buffer_addr,
	image->ima_buffer_size);
	if (ret < 0)
	return -EINVAL;

	ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
	image->ima_buffer_size);
	if (ret)
	return -EINVAL;

	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
	image->ima_buffer_addr, image->ima_buffer_size);

	return 0;
	}
	#else /* CONFIG_IMA_KEXEC */
	static inline int setup_ima_buffer(const struct kimage image, void fdt,
	int chosen_node)
	{
	return 0;
	}
	#endif /* CONFIG_IMA_KEXEC */

	/*
	* of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
	*
	* @image: kexec image being loaded.
	* @initrd_load_addr: Address where the next initrd will be loaded.
	* @initrd_len: Size of the next initrd, or 0 if there will be none.
	* @cmdline: Command line for the next kernel, or NULL if there will
	* be none.
	* @extra_fdt_size: Additional size for the new FDT buffer.
	*
	* Return: fdt on success, or NULL errno on error.
	*/
	void of_kexec_alloc_and_setup_fdt(const struct kimage image,
	unsigned long initrd_load_addr,
	unsigned long initrd_len,
	const char *cmdline, size_t extra_fdt_size)
	{
	void *fdt;
	int ret, chosen_node, len;
	const void *prop;
	size_t fdt_size;

	fdt_size = fdt_totalsize(initial_boot_params) +
	(cmdline ? strlen(cmdline) : 0) +
	FDT_EXTRA_SPACE +
	extra_fdt_size;
	fdt = kvmalloc(fdt_size, GFP_KERNEL);
	if (!fdt)
	return NULL;

	ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
	if (ret < 0) {
	pr_err("Error %d setting up the new device tree.\n", ret);
	goto out;
	}

	/* Remove memory reservation for the current device tree. */
	ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
	fdt_totalsize(initial_boot_params));
	if (ret == -EINVAL) {
	pr_err("Error removing memory reservation.\n");
	goto out;
	}

	chosen_node = fdt_path_offset(fdt, "/chosen");
	if (chosen_node == -FDT_ERR_NOTFOUND)
	chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
	"chosen");
	if (chosen_node < 0) {
	ret = chosen_node;
	goto out;
	}

	ret = fdt_delprop(fdt, chosen_node, "linux,elfcorehdr");
	if (ret && ret != -FDT_ERR_NOTFOUND)
	goto out;
	ret = fdt_delprop(fdt, chosen_node, "linux,usable-memory-range");
	if (ret && ret != -FDT_ERR_NOTFOUND)
	goto out;

	/* Did we boot using an initrd? */
	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", &len);
	if (prop) {
	u64 tmp_start, tmp_end, tmp_size;

	tmp_start = of_read_number(prop, len / 4);

	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", &len);
	if (!prop) {
	ret = -EINVAL;
	goto out;
	}

	tmp_end = of_read_number(prop, len / 4);

	/*
	* kexec reserves exact initrd size, while firmware may
	* reserve a multiple of PAGE_SIZE, so check for both.
	*/
	tmp_size = tmp_end - tmp_start;
	ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size);
	if (ret == -ENOENT)
	ret = fdt_find_and_del_mem_rsv(fdt, tmp_start,
	round_up(tmp_size, PAGE_SIZE));
	if (ret == -EINVAL)
	goto out;
	}

	/* add initrd-* */
	if (initrd_load_addr) {
	ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-start",
	initrd_load_addr);
	if (ret)
	goto out;

	ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
	initrd_load_addr + initrd_len);
	if (ret)
	goto out;

	ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
	if (ret)
	goto out;

	} else {
	ret = fdt_delprop(fdt, chosen_node, "linux,initrd-start");
	if (ret && (ret != -FDT_ERR_NOTFOUND))
	goto out;

	ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
	if (ret && (ret != -FDT_ERR_NOTFOUND))
	goto out;
	}

	if (image->type == KEXEC_TYPE_CRASH) {
	/* add linux,elfcorehdr */
	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
	"linux,elfcorehdr", image->elf_load_addr,
	image->elf_headers_sz);
	if (ret)
	goto out;

	/*
	* Avoid elfcorehdr from being stomped on in kdump kernel by
	* setting up memory reserve map.
	*/
	ret = fdt_add_mem_rsv(fdt, image->elf_load_addr,
	image->elf_headers_sz);
	if (ret)
	goto out;

	#ifdef CONFIG_CRASH_DUMP
	/* add linux,usable-memory-range */
	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
	"linux,usable-memory-range", crashk_res.start,
	crashk_res.end - crashk_res.start + 1);
	if (ret)
	goto out;

	if (crashk_low_res.end) {
	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
	"linux,usable-memory-range",
	crashk_low_res.start,
	crashk_low_res.end - crashk_low_res.start + 1);
	if (ret)
	goto out;
	}
	#endif
	}

	/* add bootargs */
	if (cmdline) {
	ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
	if (ret)
	goto out;
	} else {
	ret = fdt_delprop(fdt, chosen_node, "bootargs");
	if (ret && (ret != -FDT_ERR_NOTFOUND))
	goto out;
	}

	/* add kaslr-seed */
	ret = fdt_delprop(fdt, chosen_node, "kaslr-seed");
	if (ret == -FDT_ERR_NOTFOUND)
	ret = 0;
	else if (ret)
	goto out;

	if (rng_is_initialized()) {
	u64 seed = get_random_u64();

	ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed);
	if (ret)
	goto out;
	} else {
	pr_notice("RNG is not initialised: omitting \"%s\" property\n",
	"kaslr-seed");
	}

	/* add rng-seed */
	if (rng_is_initialized()) {
	void *rng_seed;

	ret = fdt_setprop_placeholder(fdt, chosen_node, "rng-seed",
	RNG_SEED_SIZE, &rng_seed);
	if (ret)
	goto out;
	get_random_bytes(rng_seed, RNG_SEED_SIZE);
	} else {
	pr_notice("RNG is not initialised: omitting \"%s\" property\n",
	"rng-seed");
	}

	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
	if (ret)
	goto out;

	remove_ima_buffer(fdt, chosen_node);
	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));

	out:
	if (ret) {
	kvfree(fdt);
	fdt = NULL;
	}

	return fdt;
	}