1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * kexec_file for arm64
4 *
5 * Copyright (C) 2018 Linaro Limited
6 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
7 *
8 * Most code is derived from arm64 port of kexec-tools
9 */
10
11 #define pr_fmt(fmt) "kexec_file: " fmt
12
13 #include <linux/ioport.h>
14 #include <linux/kernel.h>
15 #include <linux/kexec.h>
16 #include <linux/libfdt.h>
17 #include <linux/memblock.h>
18 #include <linux/of_fdt.h>
19 #include <linux/random.h>
20 #include <linux/slab.h>
21 #include <linux/string.h>
22 #include <linux/types.h>
23 #include <linux/vmalloc.h>
24 #include <asm/byteorder.h>
25
26 /* relevant device tree properties */
27 #define FDT_PROP_KEXEC_ELFHDR "linux,elfcorehdr"
28 #define FDT_PROP_MEM_RANGE "linux,usable-memory-range"
29 #define FDT_PROP_INITRD_START "linux,initrd-start"
30 #define FDT_PROP_INITRD_END "linux,initrd-end"
31 #define FDT_PROP_BOOTARGS "bootargs"
32 #define FDT_PROP_KASLR_SEED "kaslr-seed"
33 #define FDT_PROP_RNG_SEED "rng-seed"
34 #define RNG_SEED_SIZE 128
35
36 const struct kexec_file_ops * const kexec_file_loaders[] = {
37 &kexec_image_ops,
38 NULL
39 };
40
arch_kimage_file_post_load_cleanup(struct kimage * image)41 int arch_kimage_file_post_load_cleanup(struct kimage *image)
42 {
43 vfree(image->arch.dtb);
44 image->arch.dtb = NULL;
45
46 vfree(image->arch.elf_headers);
47 image->arch.elf_headers = NULL;
48 image->arch.elf_headers_sz = 0;
49
50 return kexec_image_post_load_cleanup_default(image);
51 }
52
setup_dtb(struct kimage * image,unsigned long initrd_load_addr,unsigned long initrd_len,char * cmdline,void * dtb)53 static int setup_dtb(struct kimage *image,
54 unsigned long initrd_load_addr, unsigned long initrd_len,
55 char *cmdline, void *dtb)
56 {
57 int off, ret;
58
59 ret = fdt_path_offset(dtb, "/chosen");
60 if (ret < 0)
61 goto out;
62
63 off = ret;
64
65 ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
66 if (ret && ret != -FDT_ERR_NOTFOUND)
67 goto out;
68 ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
69 if (ret && ret != -FDT_ERR_NOTFOUND)
70 goto out;
71
72 if (image->type == KEXEC_TYPE_CRASH) {
73 /* add linux,elfcorehdr */
74 ret = fdt_appendprop_addrrange(dtb, 0, off,
75 FDT_PROP_KEXEC_ELFHDR,
76 image->arch.elf_headers_mem,
77 image->arch.elf_headers_sz);
78 if (ret)
79 return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
80
81 /* add linux,usable-memory-range */
82 ret = fdt_appendprop_addrrange(dtb, 0, off,
83 FDT_PROP_MEM_RANGE,
84 crashk_res.start,
85 crashk_res.end - crashk_res.start + 1);
86 if (ret)
87 return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
88 }
89
90 /* add bootargs */
91 if (cmdline) {
92 ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
93 if (ret)
94 goto out;
95 } else {
96 ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS);
97 if (ret && (ret != -FDT_ERR_NOTFOUND))
98 goto out;
99 }
100
101 /* add initrd-* */
102 if (initrd_load_addr) {
103 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START,
104 initrd_load_addr);
105 if (ret)
106 goto out;
107
108 ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END,
109 initrd_load_addr + initrd_len);
110 if (ret)
111 goto out;
112 } else {
113 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START);
114 if (ret && (ret != -FDT_ERR_NOTFOUND))
115 goto out;
116
117 ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END);
118 if (ret && (ret != -FDT_ERR_NOTFOUND))
119 goto out;
120 }
121
122 /* add kaslr-seed */
123 ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED);
124 if (ret == -FDT_ERR_NOTFOUND)
125 ret = 0;
126 else if (ret)
127 goto out;
128
129 if (rng_is_initialized()) {
130 u64 seed = get_random_u64();
131 ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed);
132 if (ret)
133 goto out;
134 } else {
135 pr_notice("RNG is not initialised: omitting \"%s\" property\n",
136 FDT_PROP_KASLR_SEED);
137 }
138
139 /* add rng-seed */
140 if (rng_is_initialized()) {
141 void *rng_seed;
142 ret = fdt_setprop_placeholder(dtb, off, FDT_PROP_RNG_SEED,
143 RNG_SEED_SIZE, &rng_seed);
144 if (ret)
145 goto out;
146 get_random_bytes(rng_seed, RNG_SEED_SIZE);
147 } else {
148 pr_notice("RNG is not initialised: omitting \"%s\" property\n",
149 FDT_PROP_RNG_SEED);
150 }
151
152 out:
153 if (ret)
154 return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;
155
156 return 0;
157 }
158
159 /*
160 * More space needed so that we can add initrd, bootargs, kaslr-seed,
161 * rng-seed, userable-memory-range and elfcorehdr.
162 */
163 #define DTB_EXTRA_SPACE 0x1000
164
create_dtb(struct kimage * image,unsigned long initrd_load_addr,unsigned long initrd_len,char * cmdline,void ** dtb)165 static int create_dtb(struct kimage *image,
166 unsigned long initrd_load_addr, unsigned long initrd_len,
167 char *cmdline, void **dtb)
168 {
169 void *buf;
170 size_t buf_size;
171 size_t cmdline_len;
172 int ret;
173
174 cmdline_len = cmdline ? strlen(cmdline) : 0;
175 buf_size = fdt_totalsize(initial_boot_params)
176 + cmdline_len + DTB_EXTRA_SPACE;
177
178 for (;;) {
179 buf = vmalloc(buf_size);
180 if (!buf)
181 return -ENOMEM;
182
183 /* duplicate a device tree blob */
184 ret = fdt_open_into(initial_boot_params, buf, buf_size);
185 if (ret) {
186 vfree(buf);
187 return -EINVAL;
188 }
189
190 ret = setup_dtb(image, initrd_load_addr, initrd_len,
191 cmdline, buf);
192 if (ret) {
193 vfree(buf);
194 if (ret == -ENOMEM) {
195 /* unlikely, but just in case */
196 buf_size += DTB_EXTRA_SPACE;
197 continue;
198 } else {
199 return ret;
200 }
201 }
202
203 /* trim it */
204 fdt_pack(buf);
205 *dtb = buf;
206
207 return 0;
208 }
209 }
210
prepare_elf_headers(void ** addr,unsigned long * sz)211 static int prepare_elf_headers(void **addr, unsigned long *sz)
212 {
213 struct crash_mem *cmem;
214 unsigned int nr_ranges;
215 int ret;
216 u64 i;
217 phys_addr_t start, end;
218
219 nr_ranges = 1; /* for exclusion of crashkernel region */
220 for_each_mem_range(i, &start, &end)
221 nr_ranges++;
222
223 cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
224 if (!cmem)
225 return -ENOMEM;
226
227 cmem->max_nr_ranges = nr_ranges;
228 cmem->nr_ranges = 0;
229 for_each_mem_range(i, &start, &end) {
230 cmem->ranges[cmem->nr_ranges].start = start;
231 cmem->ranges[cmem->nr_ranges].end = end - 1;
232 cmem->nr_ranges++;
233 }
234
235 /* Exclude crashkernel region */
236 ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);
237
238 if (!ret)
239 ret = crash_prepare_elf64_headers(cmem, true, addr, sz);
240
241 kfree(cmem);
242 return ret;
243 }
244
245 /*
246 * Tries to add the initrd and DTB to the image. If it is not possible to find
247 * valid locations, this function will undo changes to the image and return non
248 * zero.
249 */
load_other_segments(struct kimage * image,unsigned long kernel_load_addr,unsigned long kernel_size,char * initrd,unsigned long initrd_len,char * cmdline)250 int load_other_segments(struct kimage *image,
251 unsigned long kernel_load_addr,
252 unsigned long kernel_size,
253 char *initrd, unsigned long initrd_len,
254 char *cmdline)
255 {
256 struct kexec_buf kbuf;
257 void *headers, *dtb = NULL;
258 unsigned long headers_sz, initrd_load_addr = 0, dtb_len,
259 orig_segments = image->nr_segments;
260 int ret = 0;
261
262 kbuf.image = image;
263 /* not allocate anything below the kernel */
264 kbuf.buf_min = kernel_load_addr + kernel_size;
265
266 /* load elf core header */
267 if (image->type == KEXEC_TYPE_CRASH) {
268 ret = prepare_elf_headers(&headers, &headers_sz);
269 if (ret) {
270 pr_err("Preparing elf core header failed\n");
271 goto out_err;
272 }
273
274 kbuf.buffer = headers;
275 kbuf.bufsz = headers_sz;
276 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
277 kbuf.memsz = headers_sz;
278 kbuf.buf_align = SZ_64K; /* largest supported page size */
279 kbuf.buf_max = ULONG_MAX;
280 kbuf.top_down = true;
281
282 ret = kexec_add_buffer(&kbuf);
283 if (ret) {
284 vfree(headers);
285 goto out_err;
286 }
287 image->arch.elf_headers = headers;
288 image->arch.elf_headers_mem = kbuf.mem;
289 image->arch.elf_headers_sz = headers_sz;
290
291 pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
292 image->arch.elf_headers_mem, kbuf.bufsz, kbuf.memsz);
293 }
294
295 /* load initrd */
296 if (initrd) {
297 kbuf.buffer = initrd;
298 kbuf.bufsz = initrd_len;
299 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
300 kbuf.memsz = initrd_len;
301 kbuf.buf_align = 0;
302 /* within 1GB-aligned window of up to 32GB in size */
303 kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
304 + (unsigned long)SZ_1G * 32;
305 kbuf.top_down = false;
306
307 ret = kexec_add_buffer(&kbuf);
308 if (ret)
309 goto out_err;
310 initrd_load_addr = kbuf.mem;
311
312 pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
313 initrd_load_addr, kbuf.bufsz, kbuf.memsz);
314 }
315
316 /* load dtb */
317 ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
318 if (ret) {
319 pr_err("Preparing for new dtb failed\n");
320 goto out_err;
321 }
322
323 dtb_len = fdt_totalsize(dtb);
324 kbuf.buffer = dtb;
325 kbuf.bufsz = dtb_len;
326 kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
327 kbuf.memsz = dtb_len;
328 /* not across 2MB boundary */
329 kbuf.buf_align = SZ_2M;
330 kbuf.buf_max = ULONG_MAX;
331 kbuf.top_down = true;
332
333 ret = kexec_add_buffer(&kbuf);
334 if (ret)
335 goto out_err;
336 image->arch.dtb = dtb;
337 image->arch.dtb_mem = kbuf.mem;
338
339 pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
340 kbuf.mem, kbuf.bufsz, kbuf.memsz);
341
342 return 0;
343
344 out_err:
345 image->nr_segments = orig_segments;
346 vfree(dtb);
347 return ret;
348 }
349