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// SPDX-License-Identifier: GPL-2.0
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/*
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 * kexec_file for LoongArch
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 *
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 * Author: Youling Tang <[email protected]>
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 * Copyright (C) 2025 KylinSoft Corporation.
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 *
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 * Most code is derived from LoongArch port of kexec-tools
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 */
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#define pr_fmt(fmt) "kexec_file: " fmt
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#include <linux/ioport.h>
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#include <linux/kernel.h>
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#include <linux/kexec.h>
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#include <linux/memblock.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/vmalloc.h>
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#include <asm/bootinfo.h>
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const struct kexec_file_ops * const kexec_file_loaders[] = {
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	&kexec_efi_ops,
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	&kexec_elf_ops,
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	NULL
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};
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int arch_kimage_file_post_load_cleanup(struct kimage *image)
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{
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	vfree(image->elf_headers);
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	image->elf_headers = NULL;
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	image->elf_headers_sz = 0;
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	return kexec_image_post_load_cleanup_default(image);
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}
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/* Add the "kexec_file" command line parameter to command line. */
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static void cmdline_add_loader(unsigned long *cmdline_tmplen, char *modified_cmdline)
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{
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	int loader_strlen;
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	loader_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "kexec_file ");
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	*cmdline_tmplen += loader_strlen;
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}
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/* Add the "initrd=start,size" command line parameter to command line. */
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static void cmdline_add_initrd(struct kimage *image, unsigned long *cmdline_tmplen,
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				char *modified_cmdline, unsigned long initrd)
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{
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	int initrd_strlen;
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	initrd_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "initrd=0x%lx,0x%lx ",
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		initrd, image->initrd_buf_len);
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	*cmdline_tmplen += initrd_strlen;
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}
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#ifdef CONFIG_CRASH_DUMP
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static int prepare_elf_headers(void **addr, unsigned long *sz)
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{
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	int ret, nr_ranges;
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	uint64_t i;
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	phys_addr_t start, end;
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	struct crash_mem *cmem;
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	nr_ranges = 2; /* for exclusion of crashkernel region */
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	for_each_mem_range(i, &start, &end)
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		nr_ranges++;
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	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
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	if (!cmem)
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		return -ENOMEM;
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	cmem->max_nr_ranges = nr_ranges;
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	cmem->nr_ranges = 0;
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	for_each_mem_range(i, &start, &end) {
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		cmem->ranges[cmem->nr_ranges].start = start;
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		cmem->ranges[cmem->nr_ranges].end = end - 1;
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		cmem->nr_ranges++;
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	}
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	/* Exclude crashkernel region */
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	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
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	if (ret < 0)
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		goto out;
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	if (crashk_low_res.end) {
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		ret = crash_exclude_mem_range(cmem, crashk_low_res.start, crashk_low_res.end);
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		if (ret < 0)
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			goto out;
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	}
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	ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
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out:
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	kfree(cmem);
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	return ret;
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}
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/*
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 * Add the "mem=size@start" command line parameter to command line, indicating the
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 * memory region the new kernel can use to boot into.
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 */
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static void cmdline_add_mem(unsigned long *cmdline_tmplen, char *modified_cmdline)
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{
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	int mem_strlen = 0;
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	mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
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		crashk_res.end - crashk_res.start + 1, crashk_res.start);
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	*cmdline_tmplen += mem_strlen;
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	if (crashk_low_res.end) {
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		mem_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "mem=0x%llx@0x%llx ",
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			crashk_low_res.end - crashk_low_res.start + 1, crashk_low_res.start);
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		*cmdline_tmplen += mem_strlen;
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	}
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}
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/* Add the "elfcorehdr=size@start" command line parameter to command line. */
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static void cmdline_add_elfcorehdr(struct kimage *image, unsigned long *cmdline_tmplen,
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				   char *modified_cmdline, unsigned long elfcorehdr_sz)
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{
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	int elfcorehdr_strlen = 0;
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	elfcorehdr_strlen = sprintf(modified_cmdline + (*cmdline_tmplen), "elfcorehdr=0x%lx@0x%lx ",
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		elfcorehdr_sz, image->elf_load_addr);
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	*cmdline_tmplen += elfcorehdr_strlen;
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}
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#endif
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/*
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 * Try to add the initrd to the image. If it is not possible to find valid
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 * locations, this function will undo changes to the image and return non zero.
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 */
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int load_other_segments(struct kimage *image,
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			unsigned long kernel_load_addr, unsigned long kernel_size,
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			char *initrd, unsigned long initrd_len, char *cmdline, unsigned long cmdline_len)
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{
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	int ret = 0;
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	unsigned long cmdline_tmplen = 0;
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	unsigned long initrd_load_addr = 0;
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	unsigned long orig_segments = image->nr_segments;
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	char *modified_cmdline = NULL;
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	struct kexec_buf kbuf;
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	kbuf.image = image;
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	/* Don't allocate anything below the kernel */
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	kbuf.buf_min = kernel_load_addr + kernel_size;
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	modified_cmdline = kzalloc(COMMAND_LINE_SIZE, GFP_KERNEL);
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	if (!modified_cmdline)
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		return -EINVAL;
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	cmdline_add_loader(&cmdline_tmplen, modified_cmdline);
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	/* Ensure it's null terminated */
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	modified_cmdline[COMMAND_LINE_SIZE - 1] = '\0';
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#ifdef CONFIG_CRASH_DUMP
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	/* Load elf core header */
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	if (image->type == KEXEC_TYPE_CRASH) {
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		void *headers;
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		unsigned long headers_sz;
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		ret = prepare_elf_headers(&headers, &headers_sz);
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		if (ret < 0) {
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			pr_err("Preparing elf core header failed\n");
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			goto out_err;
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		}
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		kbuf.buffer = headers;
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		kbuf.bufsz = headers_sz;
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		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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		kbuf.memsz = headers_sz;
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		kbuf.buf_align = SZ_64K; /* largest supported page size */
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		kbuf.buf_max = ULONG_MAX;
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		kbuf.top_down = true;
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		ret = kexec_add_buffer(&kbuf);
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		if (ret < 0) {
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			vfree(headers);
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			goto out_err;
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		}
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		image->elf_headers = headers;
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		image->elf_load_addr = kbuf.mem;
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		image->elf_headers_sz = headers_sz;
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		kexec_dprintk("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
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			      image->elf_load_addr, kbuf.bufsz, kbuf.memsz);
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		/* Add the mem=size@start parameter to the command line */
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		cmdline_add_mem(&cmdline_tmplen, modified_cmdline);
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		/* Add the elfcorehdr=size@start parameter to the command line */
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		cmdline_add_elfcorehdr(image, &cmdline_tmplen, modified_cmdline, headers_sz);
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	}
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#endif
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	/* Load initrd */
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	if (initrd) {
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		kbuf.buffer = initrd;
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		kbuf.bufsz = initrd_len;
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		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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		kbuf.memsz = initrd_len;
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		kbuf.buf_align = 0;
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		/* within 1GB-aligned window of up to 32GB in size */
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		kbuf.buf_max = round_down(kernel_load_addr, SZ_1G) + (unsigned long)SZ_1G * 32;
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		kbuf.top_down = false;
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		ret = kexec_add_buffer(&kbuf);
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		if (ret < 0)
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			goto out_err;
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		initrd_load_addr = kbuf.mem;
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		kexec_dprintk("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
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			      initrd_load_addr, kbuf.bufsz, kbuf.memsz);
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		/* Add the initrd=start,size parameter to the command line */
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		cmdline_add_initrd(image, &cmdline_tmplen, modified_cmdline, initrd_load_addr);
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	}
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	if (cmdline_len + cmdline_tmplen > COMMAND_LINE_SIZE) {
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		pr_err("Appending command line exceeds COMMAND_LINE_SIZE\n");
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		ret = -EINVAL;
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		goto out_err;
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	}
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	memcpy(modified_cmdline + cmdline_tmplen, cmdline, cmdline_len);
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	cmdline = modified_cmdline;
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	image->arch.cmdline_ptr = (unsigned long)cmdline;
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	return 0;
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out_err:
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	image->nr_segments = orig_segments;
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	kfree(modified_cmdline);
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	return ret;
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}
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