1 | // SPDX-License-Identifier: GPL-2.0 |
2 | /* |
3 | * Kexec image loader |
4 | |
5 | * Copyright (C) 2018 Linaro Limited |
6 | * Author: AKASHI Takahiro <takahiro.akashi@linaro.org> |
7 | */ |
8 | |
9 | #define pr_fmt(fmt) "kexec_file(Image): " 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 | #include <asm/memory.h> |
21 | |
22 | static int image_probe(const char *kernel_buf, unsigned long kernel_len) |
23 | { |
24 | const struct *h = |
25 | (const struct arm64_image_header *)(kernel_buf); |
26 | |
27 | if (!h || (kernel_len < sizeof(*h))) |
28 | return -EINVAL; |
29 | |
30 | if (memcmp(&h->magic, ARM64_IMAGE_MAGIC, sizeof(h->magic))) |
31 | return -EINVAL; |
32 | |
33 | return 0; |
34 | } |
35 | |
36 | static void *image_load(struct kimage *image, |
37 | char *kernel, unsigned long kernel_len, |
38 | char *initrd, unsigned long initrd_len, |
39 | char *cmdline, unsigned long cmdline_len) |
40 | { |
41 | struct *h; |
42 | u64 flags, value; |
43 | bool be_image, be_kernel; |
44 | struct kexec_buf kbuf; |
45 | unsigned long text_offset, kernel_segment_number; |
46 | struct kexec_segment *kernel_segment; |
47 | int ret; |
48 | |
49 | /* |
50 | * We require a kernel with an unambiguous Image header. Per |
51 | * Documentation/arch/arm64/booting.rst, this is the case when image_size |
52 | * is non-zero (practically speaking, since v3.17). |
53 | */ |
54 | h = (struct arm64_image_header *)kernel; |
55 | if (!h->image_size) |
56 | return ERR_PTR(error: -EINVAL); |
57 | |
58 | /* Check cpu features */ |
59 | flags = le64_to_cpu(h->flags); |
60 | be_image = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_BE); |
61 | be_kernel = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN); |
62 | if ((be_image != be_kernel) && !system_supports_mixed_endian()) |
63 | return ERR_PTR(error: -EINVAL); |
64 | |
65 | value = arm64_image_flag_field(flags, ARM64_IMAGE_FLAG_PAGE_SIZE); |
66 | if (((value == ARM64_IMAGE_FLAG_PAGE_SIZE_4K) && |
67 | !system_supports_4kb_granule()) || |
68 | ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_64K) && |
69 | !system_supports_64kb_granule()) || |
70 | ((value == ARM64_IMAGE_FLAG_PAGE_SIZE_16K) && |
71 | !system_supports_16kb_granule())) |
72 | return ERR_PTR(error: -EINVAL); |
73 | |
74 | /* Load the kernel */ |
75 | kbuf.image = image; |
76 | kbuf.buf_min = 0; |
77 | kbuf.buf_max = ULONG_MAX; |
78 | kbuf.top_down = false; |
79 | |
80 | kbuf.buffer = kernel; |
81 | kbuf.bufsz = kernel_len; |
82 | kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; |
83 | kbuf.memsz = le64_to_cpu(h->image_size); |
84 | text_offset = le64_to_cpu(h->text_offset); |
85 | kbuf.buf_align = MIN_KIMG_ALIGN; |
86 | |
87 | /* Adjust kernel segment with TEXT_OFFSET */ |
88 | kbuf.memsz += text_offset; |
89 | |
90 | kernel_segment_number = image->nr_segments; |
91 | |
92 | /* |
93 | * The location of the kernel segment may make it impossible to satisfy |
94 | * the other segment requirements, so we try repeatedly to find a |
95 | * location that will work. |
96 | */ |
97 | while ((ret = kexec_add_buffer(kbuf: &kbuf)) == 0) { |
98 | /* Try to load additional data */ |
99 | kernel_segment = &image->segment[kernel_segment_number]; |
100 | ret = load_other_segments(image, kernel_segment->mem, |
101 | kernel_segment->memsz, initrd, |
102 | initrd_len, cmdline); |
103 | if (!ret) |
104 | break; |
105 | |
106 | /* |
107 | * We couldn't find space for the other segments; erase the |
108 | * kernel segment and try the next available hole. |
109 | */ |
110 | image->nr_segments -= 1; |
111 | kbuf.buf_min = kernel_segment->mem + kernel_segment->memsz; |
112 | kbuf.mem = KEXEC_BUF_MEM_UNKNOWN; |
113 | } |
114 | |
115 | if (ret) { |
116 | pr_err("Could not find any suitable kernel location!" ); |
117 | return ERR_PTR(error: ret); |
118 | } |
119 | |
120 | kernel_segment = &image->segment[kernel_segment_number]; |
121 | kernel_segment->mem += text_offset; |
122 | kernel_segment->memsz -= text_offset; |
123 | image->start = kernel_segment->mem; |
124 | |
125 | kexec_dprintk("Loaded kernel at 0x%lx bufsz=0x%lx memsz=0x%lx\n" , |
126 | kernel_segment->mem, kbuf.bufsz, |
127 | kernel_segment->memsz); |
128 | |
129 | return NULL; |
130 | } |
131 | |
132 | const struct kexec_file_ops kexec_image_ops = { |
133 | .probe = image_probe, |
134 | .load = image_load, |
135 | #ifdef CONFIG_KEXEC_IMAGE_VERIFY_SIG |
136 | .verify_sig = kexec_kernel_verify_pe_sig, |
137 | #endif |
138 | }; |
139 | |