1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Load EFI vmlinux file for the kexec_file_load syscall.
4 *
5 * Author: Youling Tang <tangyouling@kylinos.cn>
6 * Copyright (C) 2025 KylinSoft Corporation.
7 */
8
9 #define pr_fmt(fmt) "kexec_file(EFI): " fmt
10
11 #include <linux/err.h>
12 #include <linux/errno.h>
13 #include <linux/kernel.h>
14 #include <linux/kexec.h>
15 #include <linux/pe.h>
16 #include <linux/string.h>
17 #include <asm/byteorder.h>
18 #include <asm/cpufeature.h>
19 #include <asm/image.h>
20
efi_kexec_probe(const char * kernel_buf,unsigned long kernel_len)21 static int efi_kexec_probe(const char *kernel_buf, unsigned long kernel_len)
22 {
23 const struct loongarch_image_header *h = (const struct loongarch_image_header *)kernel_buf;
24
25 if (!h || (kernel_len < sizeof(*h))) {
26 kexec_dprintk("No LoongArch image header.\n");
27 return -EINVAL;
28 }
29
30 if (!loongarch_header_check_dos_sig(h)) {
31 kexec_dprintk("No LoongArch PE image header.\n");
32 return -EINVAL;
33 }
34
35 return 0;
36 }
37
efi_kexec_load(struct kimage * image,char * kernel,unsigned long kernel_len,char * initrd,unsigned long initrd_len,char * cmdline,unsigned long cmdline_len)38 static void *efi_kexec_load(struct kimage *image,
39 char *kernel, unsigned long kernel_len,
40 char *initrd, unsigned long initrd_len,
41 char *cmdline, unsigned long cmdline_len)
42 {
43 int ret;
44 unsigned long text_offset, kernel_segment_number;
45 struct kexec_buf kbuf;
46 struct kexec_segment *kernel_segment;
47 struct loongarch_image_header *h;
48
49 h = (struct loongarch_image_header *)kernel;
50 if (!h->kernel_asize)
51 return ERR_PTR(-EINVAL);
52
53 /*
54 * Load the kernel
55 * FIXME: Non-relocatable kernel rejected for kexec_file (require CONFIG_RELOCATABLE)
56 */
57 kbuf.image = image;
58 kbuf.buf_max = ULONG_MAX;
59 kbuf.top_down = false;
60
61 kbuf.buffer = kernel;
62 kbuf.bufsz = kernel_len;
63 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
64 kbuf.memsz = le64_to_cpu(h->kernel_asize);
65 text_offset = le64_to_cpu(h->text_offset);
66 kbuf.buf_min = text_offset;
67 kbuf.buf_align = SZ_2M;
68
69 kernel_segment_number = image->nr_segments;
70
71 /*
72 * The location of the kernel segment may make it impossible to
73 * satisfy the other segment requirements, so we try repeatedly
74 * to find a location that will work.
75 */
76 while ((ret = kexec_add_buffer(&kbuf)) == 0) {
77 /* Try to load additional data */
78 kernel_segment = &image->segment[kernel_segment_number];
79 ret = load_other_segments(image, kernel_segment->mem,
80 kernel_segment->memsz, initrd,
81 initrd_len, cmdline, cmdline_len);
82 if (!ret)
83 break;
84
85 /*
86 * We couldn't find space for the other segments; erase the
87 * kernel segment and try the next available hole.
88 */
89 image->nr_segments -= 1;
90 kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz;
91 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
92 }
93
94 if (ret < 0) {
95 pr_err("Could not find any suitable kernel location!");
96 return ERR_PTR(ret);
97 }
98
99 kernel_segment = &image->segment[kernel_segment_number];
100
101 /* Make sure the second kernel jumps to the correct "kernel_entry" */
102 image->start = kernel_segment->mem + h->kernel_entry - text_offset;
103
104 kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
105 kernel_segment->mem, kbuf.bufsz, kernel_segment->memsz);
106
107 return NULL;
108 }
109
110 const struct kexec_file_ops kexec_efi_ops = {
111 .probe = efi_kexec_probe,
112 .load = efi_kexec_load,
113 };
114