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// SPDX-License-Identifier: GPL-2.0-only
/*
* Load ELF vmlinux file for the kexec_file_load syscall.
*
* Author: Youling Tang <tangyouling@kylinos.cn>
* Copyright (C) 2025 KylinSoft Corporation.
*/
#define pr_fmt(fmt) "kexec_file(ELF): " fmt
#include <linux/elf.h>
#include <linux/kexec.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/memblock.h>
#include <asm/setup.h>
#define elf_kexec_probe kexec_elf_probe
static int _elf_kexec_load(struct kimage *image,
struct elfhdr *ehdr, struct kexec_elf_info *elf_info,
struct kexec_buf *kbuf, unsigned long *text_offset)
{
int i, ret = -1;
/* Read in the PT_LOAD segments. */
for (i = 0; i < ehdr->e_phnum; i++) {
size_t size;
const struct elf_phdr *phdr;
phdr = &elf_info->proghdrs[i];
if (phdr->p_type != PT_LOAD)
continue;
size = phdr->p_filesz;
if (size > phdr->p_memsz)
size = phdr->p_memsz;
kbuf->buffer = (void *)elf_info->buffer + phdr->p_offset;
kbuf->bufsz = size;
kbuf->buf_align = phdr->p_align;
*text_offset = __pa(phdr->p_paddr);
kbuf->buf_min = *text_offset;
kbuf->memsz = ALIGN(phdr->p_memsz, SZ_64K);
kbuf->mem = KEXEC_BUF_MEM_UNKNOWN;
ret = kexec_add_buffer(kbuf);
if (ret < 0)
break;
}
return ret;
}
static void *elf_kexec_load(struct kimage *image,
char *kernel, unsigned long kernel_len,
char *initrd, unsigned long initrd_len,
char *cmdline, unsigned long cmdline_len)
{
int ret;
unsigned long text_offset, kernel_segment_number;
struct elfhdr ehdr;
struct kexec_buf kbuf;
struct kexec_elf_info elf_info;
struct kexec_segment *kernel_segment;
ret = kexec_build_elf_info(kernel, kernel_len, &ehdr, &elf_info);
if (ret < 0)
return ERR_PTR(ret);
/*
* Load the kernel
* FIXME: Non-relocatable kernel rejected for kexec_file (require CONFIG_RELOCATABLE)
*/
kbuf.image = image;
kbuf.buf_max = ULONG_MAX;
kbuf.top_down = false;
kernel_segment_number = image->nr_segments;
ret = _elf_kexec_load(image, &ehdr, &elf_info, &kbuf, &text_offset);
if (ret < 0)
goto out;
/* Load additional data */
kernel_segment = &image->segment[kernel_segment_number];
ret = load_other_segments(image, kernel_segment->mem, kernel_segment->memsz,
initrd, initrd_len, cmdline, cmdline_len);
if (ret < 0)
goto out;
/* Make sure the second kernel jumps to the correct "kernel_entry". */
image->start = kernel_segment->mem + __pa(ehdr.e_entry) - text_offset;
kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
kernel_segment->mem, kbuf.bufsz, kernel_segment->memsz);
out:
kexec_free_elf_info(&elf_info);
return ret ? ERR_PTR(ret) : NULL;
}
const struct kexec_file_ops kexec_elf_ops = {
.probe = elf_kexec_probe,
.load = elf_kexec_load,
};
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