arch/arm64/kernel/machine_kexec_file.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 /*
  * kexec_file for arm64
  *
  * Copyright (C) 2018 Linaro Limited
  * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
  *
  * Most code is derived from arm64 port of kexec-tools
  */

 #define pr_fmt(fmt) "kexec_file: " fmt

 #include <linux/ioport.h>
 #include <linux/kernel.h>
 #include <linux/kexec.h>
 #include <linux/libfdt.h>
 #include <linux/memblock.h>
 #include <linux/of_fdt.h>
 #include <linux/random.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include <linux/types.h>
 #include <linux/vmalloc.h>
 #include <asm/byteorder.h>

 /* relevant device tree properties */
 #define FDT_PROP_KEXEC_ELFHDR	"linux,elfcorehdr"
 #define FDT_PROP_MEM_RANGE	"linux,usable-memory-range"
 #define FDT_PROP_INITRD_START	"linux,initrd-start"
 #define FDT_PROP_INITRD_END	"linux,initrd-end"
 #define FDT_PROP_BOOTARGS	"bootargs"
 #define FDT_PROP_KASLR_SEED	"kaslr-seed"
 #define FDT_PROP_RNG_SEED	"rng-seed"
 #define RNG_SEED_SIZE		128

 const struct kexec_file_ops * const kexec_file_loaders[] = {
 	&kexec_image_ops,
 	NULL
 };

 int arch_kimage_file_post_load_cleanup(struct kimage *image)
 {
 	vfree(image->arch.dtb);
 	image->arch.dtb = NULL;

 	vfree(image->arch.elf_headers);
 	image->arch.elf_headers = NULL;
 	image->arch.elf_headers_sz = 0;

 	return kexec_image_post_load_cleanup_default(image);
 }

 static int setup_dtb(struct kimage *image,
 		     unsigned long initrd_load_addr, unsigned long initrd_len,
 		     char *cmdline, void *dtb)
 {
 	int off, ret;

 	ret = fdt_path_offset(dtb, "/chosen");
 	if (ret < 0)
 		goto out;

 	off = ret;

 	ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
 	if (ret && ret != -FDT_ERR_NOTFOUND)
 		goto out;
 	ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
 	if (ret && ret != -FDT_ERR_NOTFOUND)
 		goto out;

 	if (image->type == KEXEC_TYPE_CRASH) {
 		/* add linux,elfcorehdr */
 		ret = fdt_appendprop_addrrange(dtb, 0, off,
 				FDT_PROP_KEXEC_ELFHDR,
 				image->arch.elf_headers_mem,
 				image->arch.elf_headers_sz);
 		if (ret)
 			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

 		/* add linux,usable-memory-range */
 		ret = fdt_appendprop_addrrange(dtb, 0, off,
 				FDT_PROP_MEM_RANGE,
 				crashk_res.start,
 				crashk_res.end - crashk_res.start + 1);
 		if (ret)
 			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
 	}

 	/* add bootargs */
 	if (cmdline) {
 		ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
 		if (ret)
 			goto out;
 	} else {
 		ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS);
 		if (ret && (ret != -FDT_ERR_NOTFOUND))
 			goto out;
 	}

 	/* add initrd-* */
 	if (initrd_load_addr) {
 		ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START,
 				      initrd_load_addr);
 		if (ret)
 			goto out;

 		ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END,
 				      initrd_load_addr + initrd_len);
 		if (ret)
 			goto out;
 	} else {
 		ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START);
 		if (ret && (ret != -FDT_ERR_NOTFOUND))
 			goto out;

 		ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END);
 		if (ret && (ret != -FDT_ERR_NOTFOUND))
 			goto out;
 	}

 	/* add kaslr-seed */
 	ret = fdt_delprop(dtb, off, FDT_PROP_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(dtb, off, FDT_PROP_KASLR_SEED, seed);
 		if (ret)
 			goto out;
 	} else {
 		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
 				FDT_PROP_KASLR_SEED);
 	}

 	/* add rng-seed */
 	if (rng_is_initialized()) {
 		void *rng_seed;
 		ret = fdt_setprop_placeholder(dtb, off, FDT_PROP_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",
 				FDT_PROP_RNG_SEED);
 	}

 out:
 	if (ret)
 		return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;

 	return 0;
 }

 /*
  * More space needed so that we can add initrd, bootargs, kaslr-seed,
  * rng-seed, userable-memory-range and elfcorehdr.
  */
 #define DTB_EXTRA_SPACE 0x1000

 static int create_dtb(struct kimage *image,
 		      unsigned long initrd_load_addr, unsigned long initrd_len,
 		      char *cmdline, void **dtb)
 {
 	void *buf;
 	size_t buf_size;
 	size_t cmdline_len;
 	int ret;

 	cmdline_len = cmdline ? strlen(cmdline) : 0;
 	buf_size = fdt_totalsize(initial_boot_params)
 			+ cmdline_len + DTB_EXTRA_SPACE;

 	for (;;) {
 		buf = vmalloc(buf_size);
 		if (!buf)
 			return -ENOMEM;

 		/* duplicate a device tree blob */
 		ret = fdt_open_into(initial_boot_params, buf, buf_size);
 		if (ret)
 			return -EINVAL;

 		ret = setup_dtb(image, initrd_load_addr, initrd_len,
 				cmdline, buf);
 		if (ret) {
 			vfree(buf);
 			if (ret == -ENOMEM) {
 				/* unlikely, but just in case */
 				buf_size += DTB_EXTRA_SPACE;
 				continue;
 			} else {
 				return ret;
 			}
 		}

 		/* trim it */
 		fdt_pack(buf);
 		*dtb = buf;

 		return 0;
 	}
 }

 static int prepare_elf_headers(void **addr, unsigned long *sz)
 {
 	struct crash_mem *cmem;
 	unsigned int nr_ranges;
 	int ret;
 	u64 i;
 	phys_addr_t start, end;

 	nr_ranges = 1; /* for exclusion of crashkernel region */
 	for_each_mem_range(i, &start, &end)
 		nr_ranges++;

 	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
 	if (!cmem)
 		return -ENOMEM;

 	cmem->max_nr_ranges = nr_ranges;
 	cmem->nr_ranges = 0;
 	for_each_mem_range(i, &start, &end) {
 		cmem->ranges[cmem->nr_ranges].start = start;
 		cmem->ranges[cmem->nr_ranges].end = end - 1;
 		cmem->nr_ranges++;
 	}

 	/* Exclude crashkernel region */
 	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

 	if (!ret)
 		ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);

 	kfree(cmem);
 	return ret;
 }

 /*
  * Tries to add the initrd and DTB to the image. If it is not possible to find
  * valid locations, this function will undo changes to the image and return non
  * zero.
  */
 int load_other_segments(struct kimage *image,
 			unsigned long kernel_load_addr,
 			unsigned long kernel_size,
 			char *initrd, unsigned long initrd_len,
 			char *cmdline)
 {
 	struct kexec_buf kbuf;
 	void *headers, *dtb = NULL;
 	unsigned long headers_sz, initrd_load_addr = 0, dtb_len,
 		      orig_segments = image->nr_segments;
 	int ret = 0;

 	kbuf.image = image;
 	/* not allocate anything below the kernel */
 	kbuf.buf_min = kernel_load_addr + kernel_size;

 	/* load elf core header */
 	if (image->type == KEXEC_TYPE_CRASH) {
 		ret = prepare_elf_headers(&headers, &headers_sz);
 		if (ret) {
 			pr_err("Preparing elf core header failed\n");
 			goto out_err;
 		}

 		kbuf.buffer = headers;
 		kbuf.bufsz = headers_sz;
 		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 		kbuf.memsz = headers_sz;
 		kbuf.buf_align = SZ_64K; /* largest supported page size */
 		kbuf.buf_max = ULONG_MAX;
 		kbuf.top_down = true;

 		ret = kexec_add_buffer(&kbuf);
 		if (ret) {
 			vfree(headers);
 			goto out_err;
 		}
 		image->arch.elf_headers = headers;
 		image->arch.elf_headers_mem = kbuf.mem;
 		image->arch.elf_headers_sz = headers_sz;

 		pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 			 image->arch.elf_headers_mem, kbuf.bufsz, kbuf.memsz);
 	}

 	/* load initrd */
 	if (initrd) {
 		kbuf.buffer = initrd;
 		kbuf.bufsz = initrd_len;
 		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 		kbuf.memsz = initrd_len;
 		kbuf.buf_align = 0;
 		/* within 1GB-aligned window of up to 32GB in size */
 		kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
 						+ (unsigned long)SZ_1G * 32;
 		kbuf.top_down = false;

 		ret = kexec_add_buffer(&kbuf);
 		if (ret)
 			goto out_err;
 		initrd_load_addr = kbuf.mem;

 		pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 				initrd_load_addr, kbuf.bufsz, kbuf.memsz);
 	}

 	/* load dtb */
 	ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
 	if (ret) {
 		pr_err("Preparing for new dtb failed\n");
 		goto out_err;
 	}

 	dtb_len = fdt_totalsize(dtb);
 	kbuf.buffer = dtb;
 	kbuf.bufsz = dtb_len;
 	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
 	kbuf.memsz = dtb_len;
 	/* not across 2MB boundary */
 	kbuf.buf_align = SZ_2M;
 	kbuf.buf_max = ULONG_MAX;
 	kbuf.top_down = true;

 	ret = kexec_add_buffer(&kbuf);
 	if (ret)
 		goto out_err;
 	image->arch.dtb = dtb;
 	image->arch.dtb_mem = kbuf.mem;

 	pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
 			kbuf.mem, kbuf.bufsz, kbuf.memsz);

 	return 0;

 out_err:
 	image->nr_segments = orig_segments;
 	vfree(dtb);
 	return ret;
 }
	// SPDX-License-Identifier: GPL-2.0
	/*
	* kexec_file for arm64
	*
	* Copyright (C) 2018 Linaro Limited
	* Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
	*
	* Most code is derived from arm64 port of kexec-tools
	*/

	#define pr_fmt(fmt) "kexec_file: " fmt

	#include <linux/ioport.h>
	#include <linux/kernel.h>
	#include <linux/kexec.h>
	#include <linux/libfdt.h>
	#include <linux/memblock.h>
	#include <linux/of_fdt.h>
	#include <linux/random.h>
	#include <linux/slab.h>
	#include <linux/string.h>
	#include <linux/types.h>
	#include <linux/vmalloc.h>
	#include <asm/byteorder.h>

	/* relevant device tree properties */
	#define FDT_PROP_KEXEC_ELFHDR "linux,elfcorehdr"
	#define FDT_PROP_MEM_RANGE "linux,usable-memory-range"
	#define FDT_PROP_INITRD_START "linux,initrd-start"
	#define FDT_PROP_INITRD_END "linux,initrd-end"
	#define FDT_PROP_BOOTARGS "bootargs"
	#define FDT_PROP_KASLR_SEED "kaslr-seed"
	#define FDT_PROP_RNG_SEED "rng-seed"
	#define RNG_SEED_SIZE 128

	const struct kexec_file_ops * const kexec_file_loaders[] = {
	&kexec_image_ops,
	NULL
	};

	int arch_kimage_file_post_load_cleanup(struct kimage *image)
	{
	vfree(image->arch.dtb);
	image->arch.dtb = NULL;

	vfree(image->arch.elf_headers);
	image->arch.elf_headers = NULL;
	image->arch.elf_headers_sz = 0;

	return kexec_image_post_load_cleanup_default(image);
	}

	static int setup_dtb(struct kimage *image,
	unsigned long initrd_load_addr, unsigned long initrd_len,
	char cmdline, void dtb)
	{
	int off, ret;

	ret = fdt_path_offset(dtb, "/chosen");
	if (ret < 0)
	goto out;

	off = ret;

	ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
	if (ret && ret != -FDT_ERR_NOTFOUND)
	goto out;
	ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
	if (ret && ret != -FDT_ERR_NOTFOUND)
	goto out;

	if (image->type == KEXEC_TYPE_CRASH) {
	/* add linux,elfcorehdr */
	ret = fdt_appendprop_addrrange(dtb, 0, off,
	FDT_PROP_KEXEC_ELFHDR,
	image->arch.elf_headers_mem,
	image->arch.elf_headers_sz);
	if (ret)
	return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

	/* add linux,usable-memory-range */
	ret = fdt_appendprop_addrrange(dtb, 0, off,
	FDT_PROP_MEM_RANGE,
	crashk_res.start,
	crashk_res.end - crashk_res.start + 1);
	if (ret)
	return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
	}

	/* add bootargs */
	if (cmdline) {
	ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
	if (ret)
	goto out;
	} else {
	ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS);
	if (ret && (ret != -FDT_ERR_NOTFOUND))
	goto out;
	}

	/* add initrd-* */
	if (initrd_load_addr) {
	ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START,
	initrd_load_addr);
	if (ret)
	goto out;

	ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END,
	initrd_load_addr + initrd_len);
	if (ret)
	goto out;
	} else {
	ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START);
	if (ret && (ret != -FDT_ERR_NOTFOUND))
	goto out;

	ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END);
	if (ret && (ret != -FDT_ERR_NOTFOUND))
	goto out;
	}

	/* add kaslr-seed */
	ret = fdt_delprop(dtb, off, FDT_PROP_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(dtb, off, FDT_PROP_KASLR_SEED, seed);
	if (ret)
	goto out;
	} else {
	pr_notice("RNG is not initialised: omitting \"%s\" property\n",
	FDT_PROP_KASLR_SEED);
	}

	/* add rng-seed */
	if (rng_is_initialized()) {
	void *rng_seed;
	ret = fdt_setprop_placeholder(dtb, off, FDT_PROP_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",
	FDT_PROP_RNG_SEED);
	}

	out:
	if (ret)
	return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;

	return 0;
	}

	/*
	* More space needed so that we can add initrd, bootargs, kaslr-seed,
	* rng-seed, userable-memory-range and elfcorehdr.
	*/
	#define DTB_EXTRA_SPACE 0x1000

	static int create_dtb(struct kimage *image,
	unsigned long initrd_load_addr, unsigned long initrd_len,
	char cmdline, void *dtb)
	{
	void *buf;
	size_t buf_size;
	size_t cmdline_len;
	int ret;

	cmdline_len = cmdline ? strlen(cmdline) : 0;
	buf_size = fdt_totalsize(initial_boot_params)
	+ cmdline_len + DTB_EXTRA_SPACE;

	for (;;) {
	buf = vmalloc(buf_size);
	if (!buf)
	return -ENOMEM;

	/* duplicate a device tree blob */
	ret = fdt_open_into(initial_boot_params, buf, buf_size);
	if (ret)
	return -EINVAL;

	ret = setup_dtb(image, initrd_load_addr, initrd_len,
	cmdline, buf);
	if (ret) {
	vfree(buf);
	if (ret == -ENOMEM) {
	/* unlikely, but just in case */
	buf_size += DTB_EXTRA_SPACE;
	continue;
	} else {
	return ret;
	}
	}

	/* trim it */
	fdt_pack(buf);
	*dtb = buf;

	return 0;
	}
	}

	static int prepare_elf_headers(void *addr, unsigned long sz)
	{
	struct crash_mem *cmem;
	unsigned int nr_ranges;
	int ret;
	u64 i;
	phys_addr_t start, end;

	nr_ranges = 1; /* for exclusion of crashkernel region */
	for_each_mem_range(i, &start, &end)
	nr_ranges++;

	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
	if (!cmem)
	return -ENOMEM;

	cmem->max_nr_ranges = nr_ranges;
	cmem->nr_ranges = 0;
	for_each_mem_range(i, &start, &end) {
	cmem->ranges[cmem->nr_ranges].start = start;
	cmem->ranges[cmem->nr_ranges].end = end - 1;
	cmem->nr_ranges++;
	}

	/* Exclude crashkernel region */
	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

	if (!ret)
	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);

	kfree(cmem);
	return ret;
	}

	/*
	* Tries to add the initrd and DTB to the image. If it is not possible to find
	* valid locations, this function will undo changes to the image and return non
	* zero.
	*/
	int load_other_segments(struct kimage *image,
	unsigned long kernel_load_addr,
	unsigned long kernel_size,
	char *initrd, unsigned long initrd_len,
	char *cmdline)
	{
	struct kexec_buf kbuf;
	void headers, dtb = NULL;
	unsigned long headers_sz, initrd_load_addr = 0, dtb_len,
	orig_segments = image->nr_segments;
	int ret = 0;

	kbuf.image = image;
	/* not allocate anything below the kernel */
	kbuf.buf_min = kernel_load_addr + kernel_size;

	/* load elf core header */
	if (image->type == KEXEC_TYPE_CRASH) {
	ret = prepare_elf_headers(&headers, &headers_sz);
	if (ret) {
	pr_err("Preparing elf core header failed\n");
	goto out_err;
	}

	kbuf.buffer = headers;
	kbuf.bufsz = headers_sz;
	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
	kbuf.memsz = headers_sz;
	kbuf.buf_align = SZ_64K; /* largest supported page size */
	kbuf.buf_max = ULONG_MAX;
	kbuf.top_down = true;

	ret = kexec_add_buffer(&kbuf);
	if (ret) {
	vfree(headers);
	goto out_err;
	}
	image->arch.elf_headers = headers;
	image->arch.elf_headers_mem = kbuf.mem;
	image->arch.elf_headers_sz = headers_sz;

	pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
	image->arch.elf_headers_mem, kbuf.bufsz, kbuf.memsz);
	}

	/* load initrd */
	if (initrd) {
	kbuf.buffer = initrd;
	kbuf.bufsz = initrd_len;
	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
	kbuf.memsz = initrd_len;
	kbuf.buf_align = 0;
	/* within 1GB-aligned window of up to 32GB in size */
	kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
	+ (unsigned long)SZ_1G * 32;
	kbuf.top_down = false;

	ret = kexec_add_buffer(&kbuf);
	if (ret)
	goto out_err;
	initrd_load_addr = kbuf.mem;

	pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
	initrd_load_addr, kbuf.bufsz, kbuf.memsz);
	}

	/* load dtb */
	ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
	if (ret) {
	pr_err("Preparing for new dtb failed\n");
	goto out_err;
	}

	dtb_len = fdt_totalsize(dtb);
	kbuf.buffer = dtb;
	kbuf.bufsz = dtb_len;
	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
	kbuf.memsz = dtb_len;
	/* not across 2MB boundary */
	kbuf.buf_align = SZ_2M;
	kbuf.buf_max = ULONG_MAX;
	kbuf.top_down = true;

	ret = kexec_add_buffer(&kbuf);
	if (ret)
	goto out_err;
	image->arch.dtb = dtb;
	image->arch.dtb_mem = kbuf.mem;

	pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
	kbuf.mem, kbuf.bufsz, kbuf.memsz);

	return 0;

	out_err:
	image->nr_segments = orig_segments;
	vfree(dtb);
	return ret;
	}