[linux.git] / drivers / of / kexec.c

// 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;

		/* 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;
		}
	}

	/* 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;
}
Commit	Line	Data
b30be4dc RH	1	// SPDX-License-Identifier: GPL-2.0-only
	2	/*
	3	* Copyright (C) 2020 Arm Limited
	4	*
	5	* Based on arch/arm64/kernel/machine_kexec_file.c:
	6	* Copyright (C) 2018 Linaro Limited
	7	*
	8	* And arch/powerpc/kexec/file_load.c:
	9	* Copyright (C) 2016 IBM Corporation
	10	*/
	11
b69a2afd	12	#include <linux/ima.h>
b30be4dc RH	13	#include <linux/kernel.h>
b30be4dc RH	14	#include <linux/kexec.h>
fee3ff99	15	#include <linux/memblock.h>
b30be4dc RH	16	#include <linux/libfdt.h>
	17	#include <linux/of.h>
	18	#include <linux/of_fdt.h>
	19	#include <linux/random.h>
8587ca6f	20	#include <linux/slab.h>
b30be4dc RH	21	#include <linux/types.h>
b30be4dc RH	22
b30be4dc RH	23	#define RNG_SEED_SIZE 128
	24
	25	/*
	26	* Additional space needed for the FDT buffer so that we can add initrd,
	27	* bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr.
	28	*/
	29	#define FDT_EXTRA_SPACE 0x1000
	30
	31	/**
	32	* fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
	33	*
	34	* @fdt: Flattened device tree for the current kernel.
	35	* @start: Starting address of the reserved memory.
	36	* @size: Size of the reserved memory.
	37	*
	38	* Return: 0 on success, or negative errno on error.
	39	*/
	40	static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
	41	{
	42	int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
	43
	44	for (i = 0; i < num_rsvs; i++) {
	45	u64 rsv_start, rsv_size;
	46
	47	ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
	48	if (ret) {
	49	pr_err("Malformed device tree.\n");
	50	return -EINVAL;
	51	}
	52
	53	if (rsv_start == start && rsv_size == size) {
	54	ret = fdt_del_mem_rsv(fdt, i);
	55	if (ret) {
	56	pr_err("Error deleting device tree reservation.\n");
	57	return -EINVAL;
	58	}
	59
	60	return 0;
	61	}
	62	}
	63
	64	return -ENOENT;
	65	}
	66
fee3ff99 LR	67	/**
	68	* get_addr_size_cells - Get address and size of root node
	69	*
	70	* @addr_cells: Return address of the root node
	71	* @size_cells: Return size of the root node
	72	*
	73	* Return: 0 on success, or negative errno on error.
	74	*/
	75	static int get_addr_size_cells(int addr_cells, int size_cells)
	76	{
	77	struct device_node *root;
	78
	79	root = of_find_node_by_path("/");
	80	if (!root)
	81	return -EINVAL;
	82
	83	*addr_cells = of_n_addr_cells(root);
	84	*size_cells = of_n_size_cells(root);
	85
	86	of_node_put(root);
	87
	88	return 0;
	89	}
	90
	91	/**
	92	* do_get_kexec_buffer - Get address and size of device tree property
	93	*
	94	* @prop: Device tree property
	95	* @len: Size of @prop
	96	* @addr: Return address of the node
	97	* @size: Return size of the node
	98	*
	99	* Return: 0 on success, or negative errno on error.
	100	*/
	101	static int do_get_kexec_buffer(const void prop, int len, unsigned long addr,
	102	size_t *size)
	103	{
	104	int ret, addr_cells, size_cells;
	105
	106	ret = get_addr_size_cells(&addr_cells, &size_cells);
	107	if (ret)
	108	return ret;
	109
	110	if (len < 4 * (addr_cells + size_cells))
	111	return -ENOENT;
	112
	113	*addr = of_read_number(prop, addr_cells);
	114	size = of_read_number(prop + 4 addr_cells, size_cells);
	115
	116	return 0;
	117	}
	118
b69a2afd	119	#ifdef CONFIG_HAVE_IMA_KEXEC
fee3ff99 LR	120	/**
	121	* ima_get_kexec_buffer - get IMA buffer from the previous kernel
	122	* @addr: On successful return, set to point to the buffer contents.
	123	* @size: On successful return, set to the buffer size.
	124	*
	125	* Return: 0 on success, negative errno on error.
	126	*/
b69a2afd	127	int __init ima_get_kexec_buffer(void *addr, size_t size)
fee3ff99 LR	128	{
	129	int ret, len;
	130	unsigned long tmp_addr;
cbf9c4b9	131	unsigned long start_pfn, end_pfn;
fee3ff99 LR	132	size_t tmp_size;
	133	const void *prop;
	134
fee3ff99 LR	135	prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
	136	if (!prop)
	137	return -ENOENT;
	138
	139	ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
	140	if (ret)
	141	return ret;
	142
cbf9c4b9 VJ	143	/* Do some sanity on the returned size for the ima-kexec buffer */
	144	if (!tmp_size)
	145	return -ENOENT;
	146
	147	/*
	148	* Calculate the PFNs for the buffer and ensure
	149	* they are with in addressable memory.
	150	*/
	151	start_pfn = PHYS_PFN(tmp_addr);
	152	end_pfn = PHYS_PFN(tmp_addr + tmp_size - 1);
	153	if (!page_is_ram(start_pfn) \|\| !page_is_ram(end_pfn)) {
	154	pr_warn("IMA buffer at 0x%lx, size = 0x%zx beyond memory\n",
	155	tmp_addr, tmp_size);
	156	return -EINVAL;
	157	}
	158
fee3ff99 LR	159	*addr = __va(tmp_addr);
	160	*size = tmp_size;
	161
	162	return 0;
	163	}
	164
	165	/**
	166	* ima_free_kexec_buffer - free memory used by the IMA buffer
	167	*/
b69a2afd	168	int __init ima_free_kexec_buffer(void)
fee3ff99 LR	169	{
	170	int ret;
	171	unsigned long addr;
	172	size_t size;
	173	struct property *prop;
	174
fee3ff99 LR	175	prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
	176	if (!prop)
	177	return -ENOENT;
	178
	179	ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
	180	if (ret)
	181	return ret;
	182
	183	ret = of_remove_property(of_chosen, prop);
	184	if (ret)
	185	return ret;
	186
f0362a25 RR	187	memblock_free_late(addr, size);
f0362a25 RR	188	return 0;
fee3ff99	189	}
b69a2afd	190	#endif
fee3ff99 LR	191
	192	/**
	193	* remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
	194	*
	195	* @fdt: Flattened Device Tree to update
	196	* @chosen_node: Offset to the chosen node in the device tree
	197	*
	198	* The IMA measurement buffer is of no use to a subsequent kernel, so we always
	199	* remove it from the device tree.
	200	*/
	201	static void remove_ima_buffer(void *fdt, int chosen_node)
	202	{
	203	int ret, len;
	204	unsigned long addr;
	205	size_t size;
	206	const void *prop;
	207
	208	if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
	209	return;
	210
	211	prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
	212	if (!prop)
	213	return;
	214
	215	ret = do_get_kexec_buffer(prop, len, &addr, &size);
	216	fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
	217	if (ret)
	218	return;
	219
	220	ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
	221	if (!ret)
	222	pr_debug("Removed old IMA buffer reservation.\n");
	223	}
	224
	225	#ifdef CONFIG_IMA_KEXEC
fee3ff99 LR	226	/**
	227	* setup_ima_buffer - add IMA buffer information to the fdt
	228	* @image: kexec image being loaded.
	229	* @fdt: Flattened device tree for the next kernel.
	230	* @chosen_node: Offset to the chosen node.
	231	*
	232	* Return: 0 on success, or negative errno on error.
	233	*/
	234	static int setup_ima_buffer(const struct kimage image, void fdt,
	235	int chosen_node)
	236	{
28db15d4	237	int ret;
fee3ff99 LR	238
	239	if (!image->ima_buffer_size)
	240	return 0;
	241
28db15d4 LR	242	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
	243	"linux,ima-kexec-buffer",
	244	image->ima_buffer_addr,
	245	image->ima_buffer_size);
fee3ff99 LR	246	if (ret < 0)
	247	return -EINVAL;
	248
	249	ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
	250	image->ima_buffer_size);
	251	if (ret)
	252	return -EINVAL;
	253
	254	pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
	255	image->ima_buffer_addr, image->ima_buffer_size);
	256
	257	return 0;
	258	}
	259	#else /* CONFIG_IMA_KEXEC */
	260	static inline int setup_ima_buffer(const struct kimage image, void fdt,
	261	int chosen_node)
	262	{
	263	return 0;
	264	}
	265	#endif /* CONFIG_IMA_KEXEC */
	266
b30be4dc RH	267	/*
	268	* of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
	269	*
	270	* @image: kexec image being loaded.
	271	* @initrd_load_addr: Address where the next initrd will be loaded.
	272	* @initrd_len: Size of the next initrd, or 0 if there will be none.
	273	* @cmdline: Command line for the next kernel, or NULL if there will
	274	* be none.
	275	* @extra_fdt_size: Additional size for the new FDT buffer.
	276	*
	277	* Return: fdt on success, or NULL errno on error.
	278	*/
	279	void of_kexec_alloc_and_setup_fdt(const struct kimage image,
	280	unsigned long initrd_load_addr,
	281	unsigned long initrd_len,
	282	const char *cmdline, size_t extra_fdt_size)
	283	{
	284	void *fdt;
e553ad8d	285	int ret, chosen_node, len;
b30be4dc RH	286	const void *prop;
	287	size_t fdt_size;
	288
	289	fdt_size = fdt_totalsize(initial_boot_params) +
	290	(cmdline ? strlen(cmdline) : 0) +
	291	FDT_EXTRA_SPACE +
	292	extra_fdt_size;
	293	fdt = kvmalloc(fdt_size, GFP_KERNEL);
	294	if (!fdt)
	295	return NULL;
	296
	297	ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
	298	if (ret < 0) {
	299	pr_err("Error %d setting up the new device tree.\n", ret);
	300	goto out;
	301	}
	302
	303	/* Remove memory reservation for the current device tree. */
	304	ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
	305	fdt_totalsize(initial_boot_params));
	306	if (ret == -EINVAL) {
	307	pr_err("Error removing memory reservation.\n");
	308	goto out;
	309	}
	310
	311	chosen_node = fdt_path_offset(fdt, "/chosen");
	312	if (chosen_node == -FDT_ERR_NOTFOUND)
	313	chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
	314	"chosen");
	315	if (chosen_node < 0) {
	316	ret = chosen_node;
	317	goto out;
	318	}
	319
cc6ef3d1	320	ret = fdt_delprop(fdt, chosen_node, "linux,elfcorehdr");
b30be4dc RH	321	if (ret && ret != -FDT_ERR_NOTFOUND)
b30be4dc RH	322	goto out;
cc6ef3d1	323	ret = fdt_delprop(fdt, chosen_node, "linux,usable-memory-range");
b30be4dc RH	324	if (ret && ret != -FDT_ERR_NOTFOUND)
	325	goto out;
	326
	327	/* Did we boot using an initrd? */
e553ad8d	328	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", &len);
b30be4dc RH	329	if (prop) {
	330	u64 tmp_start, tmp_end, tmp_size;
	331
e553ad8d	332	tmp_start = of_read_number(prop, len / 4);
b30be4dc	333
e553ad8d	334	prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", &len);
b30be4dc RH	335	if (!prop) {
	336	ret = -EINVAL;
	337	goto out;
	338	}
	339
e553ad8d	340	tmp_end = of_read_number(prop, len / 4);
b30be4dc RH	341
	342	/*
	343	* kexec reserves exact initrd size, while firmware may
	344	* reserve a multiple of PAGE_SIZE, so check for both.
	345	*/
	346	tmp_size = tmp_end - tmp_start;
	347	ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size);
	348	if (ret == -ENOENT)
	349	ret = fdt_find_and_del_mem_rsv(fdt, tmp_start,
	350	round_up(tmp_size, PAGE_SIZE));
	351	if (ret == -EINVAL)
	352	goto out;
	353	}
	354
	355	/* add initrd-* */
	356	if (initrd_load_addr) {
cc6ef3d1	357	ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-start",
b30be4dc RH	358	initrd_load_addr);
	359	if (ret)
	360	goto out;
	361
cc6ef3d1	362	ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
b30be4dc RH	363	initrd_load_addr + initrd_len);
	364	if (ret)
	365	goto out;
	366
	367	ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
	368	if (ret)
	369	goto out;
	370
	371	} else {
cc6ef3d1	372	ret = fdt_delprop(fdt, chosen_node, "linux,initrd-start");
b30be4dc RH	373	if (ret && (ret != -FDT_ERR_NOTFOUND))
	374	goto out;
	375
cc6ef3d1	376	ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
b30be4dc RH	377	if (ret && (ret != -FDT_ERR_NOTFOUND))
	378	goto out;
	379	}
	380
	381	if (image->type == KEXEC_TYPE_CRASH) {
	382	/* add linux,elfcorehdr */
	383	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
cc6ef3d1	384	"linux,elfcorehdr", image->elf_load_addr,
b30be4dc RH	385	image->elf_headers_sz);
	386	if (ret)
	387	goto out;
	388
	389	/*
	390	* Avoid elfcorehdr from being stomped on in kdump kernel by
	391	* setting up memory reserve map.
	392	*/
	393	ret = fdt_add_mem_rsv(fdt, image->elf_load_addr,
	394	image->elf_headers_sz);
	395	if (ret)
	396	goto out;
	397
	398	/* add linux,usable-memory-range */
	399	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
cc6ef3d1	400	"linux,usable-memory-range", crashk_res.start,
b30be4dc RH	401	crashk_res.end - crashk_res.start + 1);
	402	if (ret)
	403	goto out;
8af6b91f ZL	404
	405	if (crashk_low_res.end) {
	406	ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
	407	"linux,usable-memory-range",
	408	crashk_low_res.start,
	409	crashk_low_res.end - crashk_low_res.start + 1);
	410	if (ret)
	411	goto out;
	412	}
b30be4dc RH	413	}
	414
	415	/* add bootargs */
	416	if (cmdline) {
cc6ef3d1	417	ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
b30be4dc RH	418	if (ret)
	419	goto out;
	420	} else {
cc6ef3d1	421	ret = fdt_delprop(fdt, chosen_node, "bootargs");
b30be4dc RH	422	if (ret && (ret != -FDT_ERR_NOTFOUND))
	423	goto out;
	424	}
	425
	426	/* add kaslr-seed */
cc6ef3d1	427	ret = fdt_delprop(fdt, chosen_node, "kaslr-seed");
b30be4dc RH	428	if (ret == -FDT_ERR_NOTFOUND)
	429	ret = 0;
	430	else if (ret)
	431	goto out;
	432
	433	if (rng_is_initialized()) {
	434	u64 seed = get_random_u64();
	435
cc6ef3d1	436	ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed);
b30be4dc RH	437	if (ret)
	438	goto out;
	439	} else {
	440	pr_notice("RNG is not initialised: omitting \"%s\" property\n",
cc6ef3d1	441	"kaslr-seed");
b30be4dc RH	442	}
	443
	444	/* add rng-seed */
	445	if (rng_is_initialized()) {
	446	void *rng_seed;
	447
cc6ef3d1	448	ret = fdt_setprop_placeholder(fdt, chosen_node, "rng-seed",
b30be4dc RH	449	RNG_SEED_SIZE, &rng_seed);
	450	if (ret)
	451	goto out;
	452	get_random_bytes(rng_seed, RNG_SEED_SIZE);
	453	} else {
	454	pr_notice("RNG is not initialised: omitting \"%s\" property\n",
cc6ef3d1	455	"rng-seed");
b30be4dc RH	456	}
	457
	458	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
fee3ff99 LR	459	if (ret)
	460	goto out;
	461
	462	remove_ima_buffer(fdt, chosen_node);
	463	ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
b30be4dc RH	464
	465	out:
	466	if (ret) {
	467	kvfree(fdt);
	468	fdt = NULL;
	469	}
	470
	471	return fdt;
	472	}