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// SPDX-License-Identifier: GPL-2.0
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/*
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 * Load EFI vmlinux file for the kexec_file_load syscall.
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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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#define pr_fmt(fmt)	"kexec_file(EFI): " fmt
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#include <linux/err.h>
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/kexec.h>
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#include <linux/pe.h>
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#include <linux/string.h>
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#include <asm/byteorder.h>
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#include <asm/cpufeature.h>
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#include <asm/image.h>
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static int efi_kexec_probe(const char *kernel_buf, unsigned long kernel_len)
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{
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	const struct loongarch_image_header *h = (const struct loongarch_image_header *)kernel_buf;
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	if (!h || (kernel_len < sizeof(*h))) {
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		kexec_dprintk("No LoongArch image header.\n");
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		return -EINVAL;
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	}
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	if (!loongarch_header_check_dos_sig(h)) {
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		kexec_dprintk("No LoongArch PE image header.\n");
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		return -EINVAL;
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	}
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	return 0;
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}
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static void *efi_kexec_load(struct kimage *image,
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				char *kernel, unsigned long kernel_len,
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				char *initrd, unsigned long initrd_len,
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				char *cmdline, unsigned long cmdline_len)
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{
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	int ret;
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	unsigned long text_offset, kernel_segment_number;
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	struct kexec_buf kbuf;
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	struct kexec_segment *kernel_segment;
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	struct loongarch_image_header *h;
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	h = (struct loongarch_image_header *)kernel;
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	if (!h->kernel_asize)
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		return ERR_PTR(-EINVAL);
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	/*
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	 * Load the kernel
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	 * FIXME: Non-relocatable kernel rejected for kexec_file (require CONFIG_RELOCATABLE)
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	 */
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	kbuf.image = image;
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	kbuf.buf_max = ULONG_MAX;
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	kbuf.top_down = false;
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	kbuf.buffer = kernel;
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	kbuf.bufsz = kernel_len;
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	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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	kbuf.memsz = le64_to_cpu(h->kernel_asize);
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	text_offset = le64_to_cpu(h->text_offset);
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	kbuf.buf_min = text_offset;
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	kbuf.buf_align = SZ_2M;
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	kernel_segment_number = image->nr_segments;
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	/*
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	 * The location of the kernel segment may make it impossible to
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	 * satisfy the other segment requirements, so we try repeatedly
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	 * to find a location that will work.
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	 */
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	while ((ret = kexec_add_buffer(&kbuf)) == 0) {
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		/* Try to load additional data */
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		kernel_segment = &image->segment[kernel_segment_number];
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		ret = load_other_segments(image, kernel_segment->mem,
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					  kernel_segment->memsz, initrd,
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					  initrd_len, cmdline, cmdline_len);
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		if (!ret)
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			break;
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		/*
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		 * We couldn't find space for the other segments; erase the
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		 * kernel segment and try the next available hole.
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		 */
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		image->nr_segments -= 1;
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		kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz;
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		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
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	}
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	if (ret < 0) {
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		pr_err("Could not find any suitable kernel location!");
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		return ERR_PTR(ret);
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	}
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	kernel_segment = &image->segment[kernel_segment_number];
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	/* Make sure the second kernel jumps to the correct "kernel_entry" */
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	image->start = kernel_segment->mem + h->kernel_entry - text_offset;
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	kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
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		      kernel_segment->mem, kbuf.bufsz, kernel_segment->memsz);
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	return NULL;
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}
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const struct kexec_file_ops kexec_efi_ops = {
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	.probe = efi_kexec_probe,
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	.load = efi_kexec_load,
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};
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