1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Load ELF vmlinux file for the kexec_file_load syscall.
4 *
5 * Copyright (c) 2019 Sven Schnelle <svens@stackframe.org>
6 *
7 */
8#include <linux/elf.h>
9#include <linux/kexec.h>
10#include <linux/libfdt.h>
11#include <linux/module.h>
12#include <linux/of_fdt.h>
13#include <linux/slab.h>
14#include <linux/types.h>
15
16static void *elf_load(struct kimage *image, char *kernel_buf,
17			unsigned long kernel_len, char *initrd,
18			unsigned long initrd_len, char *cmdline,
19			unsigned long cmdline_len)
20{
21	int ret, i;
22	unsigned long kernel_load_addr;
23	struct elfhdr ehdr;
24	struct kexec_elf_info elf_info;
25	struct kexec_buf kbuf = { .image = image, .buf_min = 0,
26				  .buf_max = -1UL, };
27
28	ret = kexec_build_elf_info(kernel_buf, kernel_len, &ehdr, &elf_info);
29	if (ret)
30		goto out;
31
32	ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr);
33	if (ret)
34		goto out;
35
36	image->start = __pa(elf_info.ehdr->e_entry);
37
38	for (i = 0; i < image->nr_segments; i++)
39		image->segment[i].mem = __pa(image->segment[i].mem);
40
41	kexec_dprintk("Loaded the kernel at 0x%lx, entry at 0x%lx\n",
42		      kernel_load_addr, image->start);
43
44	if (initrd != NULL) {
45		kbuf.buffer = initrd;
46		kbuf.bufsz = kbuf.memsz = initrd_len;
47		kbuf.buf_align = PAGE_SIZE;
48		kbuf.top_down = false;
49		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
50		ret = kexec_add_buffer(&kbuf);
51		if (ret)
52			goto out;
53
54		kexec_dprintk("Loaded initrd at 0x%lx\n", kbuf.mem);
55		image->arch.initrd_start = kbuf.mem;
56		image->arch.initrd_end = kbuf.mem + initrd_len;
57	}
58
59	if (cmdline != NULL) {
60		kbuf.buffer = cmdline;
61		kbuf.bufsz = kbuf.memsz = ALIGN(cmdline_len, 8);
62		kbuf.buf_align = PAGE_SIZE;
63		kbuf.top_down = false;
64		kbuf.buf_min = PAGE0->mem_free + PAGE_SIZE;
65		kbuf.buf_max = kernel_load_addr;
66		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
67		ret = kexec_add_buffer(&kbuf);
68		if (ret)
69			goto out;
70
71		kexec_dprintk("Loaded cmdline at 0x%lx\n", kbuf.mem);
72		image->arch.cmdline = kbuf.mem;
73	}
74out:
75	return NULL;
76}
77
78const struct kexec_file_ops kexec_elf_ops = {
79	.probe = kexec_elf_probe,
80	.load = elf_load,
81};
82
83const struct kexec_file_ops * const kexec_file_loaders[] = {
84	&kexec_elf_ops,
85	NULL
86};
87