summaryrefslogtreecommitdiffstats
path: root/arch/arm64/kernel/machine_kexec_file.c
blob: 5b0e67b93cdcda8c839e7b52fccdff04c3151d10 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
// SPDX-License-Identifier: GPL-2.0
/*
 * kexec_file for arm64
 *
 * Copyright (C) 2018 Linaro Limited
 * Author: AKASHI Takahiro <takahiro.akashi@linaro.org>
 *
 * Most code is derived from arm64 port of kexec-tools
 */

#define pr_fmt(fmt) "kexec_file: " fmt

#include <linux/ioport.h>
#include <linux/kernel.h>
#include <linux/kexec.h>
#include <linux/libfdt.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/vmalloc.h>
#include <asm/byteorder.h>

/* relevant device tree properties */
#define FDT_PROP_KEXEC_ELFHDR	"linux,elfcorehdr"
#define FDT_PROP_MEM_RANGE	"linux,usable-memory-range"
#define FDT_PROP_INITRD_START	"linux,initrd-start"
#define FDT_PROP_INITRD_END	"linux,initrd-end"
#define FDT_PROP_BOOTARGS	"bootargs"
#define FDT_PROP_KASLR_SEED	"kaslr-seed"
#define FDT_PROP_RNG_SEED	"rng-seed"
#define RNG_SEED_SIZE		128

const struct kexec_file_ops * const kexec_file_loaders[] = {
	&kexec_image_ops,
	NULL
};

int arch_kimage_file_post_load_cleanup(struct kimage *image)
{
	vfree(image->arch.dtb);
	image->arch.dtb = NULL;

	vfree(image->arch.elf_headers);
	image->arch.elf_headers = NULL;
	image->arch.elf_headers_sz = 0;

	return kexec_image_post_load_cleanup_default(image);
}

static int setup_dtb(struct kimage *image,
		     unsigned long initrd_load_addr, unsigned long initrd_len,
		     char *cmdline, void *dtb)
{
	int off, ret;

	ret = fdt_path_offset(dtb, "/chosen");
	if (ret < 0)
		goto out;

	off = ret;

	ret = fdt_delprop(dtb, off, FDT_PROP_KEXEC_ELFHDR);
	if (ret && ret != -FDT_ERR_NOTFOUND)
		goto out;
	ret = fdt_delprop(dtb, off, FDT_PROP_MEM_RANGE);
	if (ret && ret != -FDT_ERR_NOTFOUND)
		goto out;

	if (image->type == KEXEC_TYPE_CRASH) {
		/* add linux,elfcorehdr */
		ret = fdt_appendprop_addrrange(dtb, 0, off,
				FDT_PROP_KEXEC_ELFHDR,
				image->arch.elf_headers_mem,
				image->arch.elf_headers_sz);
		if (ret)
			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);

		/* add linux,usable-memory-range */
		ret = fdt_appendprop_addrrange(dtb, 0, off,
				FDT_PROP_MEM_RANGE,
				crashk_res.start,
				crashk_res.end - crashk_res.start + 1);
		if (ret)
			return (ret == -FDT_ERR_NOSPACE ? -ENOMEM : -EINVAL);
	}

	/* add bootargs */
	if (cmdline) {
		ret = fdt_setprop_string(dtb, off, FDT_PROP_BOOTARGS, cmdline);
		if (ret)
			goto out;
	} else {
		ret = fdt_delprop(dtb, off, FDT_PROP_BOOTARGS);
		if (ret && (ret != -FDT_ERR_NOTFOUND))
			goto out;
	}

	/* add initrd-* */
	if (initrd_load_addr) {
		ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_START,
				      initrd_load_addr);
		if (ret)
			goto out;

		ret = fdt_setprop_u64(dtb, off, FDT_PROP_INITRD_END,
				      initrd_load_addr + initrd_len);
		if (ret)
			goto out;
	} else {
		ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_START);
		if (ret && (ret != -FDT_ERR_NOTFOUND))
			goto out;

		ret = fdt_delprop(dtb, off, FDT_PROP_INITRD_END);
		if (ret && (ret != -FDT_ERR_NOTFOUND))
			goto out;
	}

	/* add kaslr-seed */
	ret = fdt_delprop(dtb, off, FDT_PROP_KASLR_SEED);
	if (ret == -FDT_ERR_NOTFOUND)
		ret = 0;
	else if (ret)
		goto out;

	if (rng_is_initialized()) {
		u64 seed = get_random_u64();
		ret = fdt_setprop_u64(dtb, off, FDT_PROP_KASLR_SEED, seed);
		if (ret)
			goto out;
	} else {
		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
				FDT_PROP_KASLR_SEED);
	}

	/* add rng-seed */
	if (rng_is_initialized()) {
		void *rng_seed;
		ret = fdt_setprop_placeholder(dtb, off, FDT_PROP_RNG_SEED,
				RNG_SEED_SIZE, &rng_seed);
		if (ret)
			goto out;
		get_random_bytes(rng_seed, RNG_SEED_SIZE);
	} else {
		pr_notice("RNG is not initialised: omitting \"%s\" property\n",
				FDT_PROP_RNG_SEED);
	}

out:
	if (ret)
		return (ret == -FDT_ERR_NOSPACE) ? -ENOMEM : -EINVAL;

	return 0;
}

/*
 * More space needed so that we can add initrd, bootargs, kaslr-seed,
 * rng-seed, userable-memory-range and elfcorehdr.
 */
#define DTB_EXTRA_SPACE 0x1000

static int create_dtb(struct kimage *image,
		      unsigned long initrd_load_addr, unsigned long initrd_len,
		      char *cmdline, void **dtb)
{
	void *buf;
	size_t buf_size;
	size_t cmdline_len;
	int ret;

	cmdline_len = cmdline ? strlen(cmdline) : 0;
	buf_size = fdt_totalsize(initial_boot_params)
			+ cmdline_len + DTB_EXTRA_SPACE;

	for (;;) {
		buf = vmalloc(buf_size);
		if (!buf)
			return -ENOMEM;

		/* duplicate a device tree blob */
		ret = fdt_open_into(initial_boot_params, buf, buf_size);
		if (ret)
			return -EINVAL;

		ret = setup_dtb(image, initrd_load_addr, initrd_len,
				cmdline, buf);
		if (ret) {
			vfree(buf);
			if (ret == -ENOMEM) {
				/* unlikely, but just in case */
				buf_size += DTB_EXTRA_SPACE;
				continue;
			} else {
				return ret;
			}
		}

		/* trim it */
		fdt_pack(buf);
		*dtb = buf;

		return 0;
	}
}

static int prepare_elf_headers(void **addr, unsigned long *sz)
{
	struct crash_mem *cmem;
	unsigned int nr_ranges;
	int ret;
	u64 i;
	phys_addr_t start, end;

	nr_ranges = 1; /* for exclusion of crashkernel region */
	for_each_mem_range(i, &start, &end)
		nr_ranges++;

	cmem = kmalloc(struct_size(cmem, ranges, nr_ranges), GFP_KERNEL);
	if (!cmem)
		return -ENOMEM;

	cmem->max_nr_ranges = nr_ranges;
	cmem->nr_ranges = 0;
	for_each_mem_range(i, &start, &end) {
		cmem->ranges[cmem->nr_ranges].start = start;
		cmem->ranges[cmem->nr_ranges].end = end - 1;
		cmem->nr_ranges++;
	}

	/* Exclude crashkernel region */
	ret = crash_exclude_mem_range(cmem, crashk_res.start, crashk_res.end);

	if (!ret)
		ret =  crash_prepare_elf64_headers(cmem, true, addr, sz);

	kfree(cmem);
	return ret;
}

int load_other_segments(struct kimage *image,
			unsigned long kernel_load_addr,
			unsigned long kernel_size,
			char *initrd, unsigned long initrd_len,
			char *cmdline)
{
	struct kexec_buf kbuf;
	void *headers, *dtb = NULL;
	unsigned long headers_sz, initrd_load_addr = 0, dtb_len;
	int ret = 0;

	kbuf.image = image;
	/* not allocate anything below the kernel */
	kbuf.buf_min = kernel_load_addr + kernel_size;

	/* load elf core header */
	if (image->type == KEXEC_TYPE_CRASH) {
		ret = prepare_elf_headers(&headers, &headers_sz);
		if (ret) {
			pr_err("Preparing elf core header failed\n");
			goto out_err;
		}

		kbuf.buffer = headers;
		kbuf.bufsz = headers_sz;
		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
		kbuf.memsz = headers_sz;
		kbuf.buf_align = SZ_64K; /* largest supported page size */
		kbuf.buf_max = ULONG_MAX;
		kbuf.top_down = true;

		ret = kexec_add_buffer(&kbuf);
		if (ret) {
			vfree(headers);
			goto out_err;
		}
		image->arch.elf_headers = headers;
		image->arch.elf_headers_mem = kbuf.mem;
		image->arch.elf_headers_sz = headers_sz;

		pr_debug("Loaded elf core header at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
			 image->arch.elf_headers_mem, kbuf.bufsz, kbuf.memsz);
	}

	/* load initrd */
	if (initrd) {
		kbuf.buffer = initrd;
		kbuf.bufsz = initrd_len;
		kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
		kbuf.memsz = initrd_len;
		kbuf.buf_align = 0;
		/* within 1GB-aligned window of up to 32GB in size */
		kbuf.buf_max = round_down(kernel_load_addr, SZ_1G)
						+ (unsigned long)SZ_1G * 32;
		kbuf.top_down = false;

		ret = kexec_add_buffer(&kbuf);
		if (ret)
			goto out_err;
		initrd_load_addr = kbuf.mem;

		pr_debug("Loaded initrd at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
				initrd_load_addr, kbuf.bufsz, kbuf.memsz);
	}

	/* load dtb */
	ret = create_dtb(image, initrd_load_addr, initrd_len, cmdline, &dtb);
	if (ret) {
		pr_err("Preparing for new dtb failed\n");
		goto out_err;
	}

	dtb_len = fdt_totalsize(dtb);
	kbuf.buffer = dtb;
	kbuf.bufsz = dtb_len;
	kbuf.mem = KEXEC_BUF_MEM_UNKNOWN;
	kbuf.memsz = dtb_len;
	/* not across 2MB boundary */
	kbuf.buf_align = SZ_2M;
	kbuf.buf_max = ULONG_MAX;
	kbuf.top_down = true;

	ret = kexec_add_buffer(&kbuf);
	if (ret)
		goto out_err;
	image->arch.dtb = dtb;
	image->arch.dtb_mem = kbuf.mem;

	pr_debug("Loaded dtb at 0x%lx bufsz=0x%lx memsz=0x%lx\n",
			kbuf.mem, kbuf.bufsz, kbuf.memsz);

	return 0;

out_err:
	vfree(dtb);
	return ret;
}