summaryrefslogtreecommitdiffstats
path: root/scripts/mips-relocs.c
blob: 791615958158bb7f7abd1b3bb0b8d4c73ba68cfb (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
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * MIPS Relocation Data Generator
 *
 * Copyright (c) 2017 Imagination Technologies Ltd.
 */

#include <assert.h>
#include <elf.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <unistd.h>

#include <../../arch/mips/include/asm/relocs.h>

#define hdr_field(pfx, idx, field) ({				\
	uint64_t _val;						\
	unsigned int _size;					\
								\
	if (is_64) {						\
		_val = pfx##hdr64[idx].field;			\
		_size = sizeof(pfx##hdr64[0].field);		\
	} else {						\
		_val = pfx##hdr32[idx].field;			\
		_size = sizeof(pfx##hdr32[0].field);		\
	}							\
								\
	switch (_size) {					\
	case 1:							\
		break;						\
	case 2:							\
		_val = is_be ? be16toh(_val) : le16toh(_val);	\
		break;						\
	case 4:							\
		_val = is_be ? be32toh(_val) : le32toh(_val);	\
		break;						\
	case 8:							\
		_val = is_be ? be64toh(_val) : le64toh(_val);	\
		break;						\
	}							\
								\
	_val;							\
})

#define set_hdr_field(pfx, idx, field, val) ({			\
	uint64_t _val;						\
	unsigned int _size;					\
								\
	if (is_64)						\
		_size = sizeof(pfx##hdr64[0].field);		\
	else							\
		_size = sizeof(pfx##hdr32[0].field);		\
								\
	switch (_size) {					\
	case 1:							\
		_val = val;					\
		break;						\
	case 2:							\
		_val = is_be ? htobe16(val) : htole16(val);	\
		break;						\
	case 4:							\
		_val = is_be ? htobe32(val) : htole32(val);	\
		break;						\
	case 8:							\
		_val = is_be ? htobe64(val) : htole64(val);	\
		break;						\
	default:						\
		/* We should never reach here */		\
		_val = 0;					\
		assert(0);					\
		break;						\
	}							\
								\
	if (is_64)						\
		pfx##hdr64[idx].field = _val;			\
	else							\
		pfx##hdr32[idx].field = _val;			\
})

#define ehdr_field(field) \
	hdr_field(e, 0, field)
#define phdr_field(idx, field) \
	hdr_field(p, idx, field)
#define shdr_field(idx, field) \
	hdr_field(s, idx, field)

#define set_phdr_field(idx, field, val) \
	set_hdr_field(p, idx, field, val)
#define set_shdr_field(idx, field, val) \
	set_hdr_field(s, idx, field, val)

#define shstr(idx) (&shstrtab[idx])

bool is_64, is_be;
uint64_t text_base;

struct mips_reloc {
	uint8_t type;
	uint64_t offset;
} *relocs;
size_t relocs_sz, relocs_idx;

static int add_reloc(unsigned int type, uint64_t off)
{
	struct mips_reloc *new;
	size_t new_sz;

	switch (type) {
	case R_MIPS_NONE:
	case R_MIPS_LO16:
	case R_MIPS_PC16:
	case R_MIPS_HIGHER:
	case R_MIPS_HIGHEST:
	case R_MIPS_PC21_S2:
	case R_MIPS_PC26_S2:
		/* Skip these relocs */
		return 0;

	default:
		break;
	}

	if (relocs_idx == relocs_sz) {
		new_sz = relocs_sz ? relocs_sz * 2 : 128;
		new = realloc(relocs, new_sz * sizeof(*relocs));
		if (!new) {
			fprintf(stderr, "Out of memory\n");
			return -ENOMEM;
		}

		relocs = new;
		relocs_sz = new_sz;
	}

	relocs[relocs_idx++] = (struct mips_reloc){
		.type = type,
		.offset = off,
	};

	return 0;
}

static int parse_mips32_rel(const void *_rel)
{
	const Elf32_Rel *rel = _rel;
	uint32_t off, type;

	off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset);
	off -= text_base;

	type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info);
	type = ELF32_R_TYPE(type);

	return add_reloc(type, off);
}

static int parse_mips64_rela(const void *_rel)
{
	const Elf64_Rela *rel = _rel;
	uint64_t off, type;

	off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset);
	off -= text_base;

	type = rel->r_info >> (64 - 8);

	return add_reloc(type, off);
}

static void output_uint(uint8_t **buf, uint64_t val)
{
	uint64_t tmp;

	do {
		tmp = val & 0x7f;
		val >>= 7;
		tmp |= !!val << 7;
		*(*buf)++ = tmp;
	} while (val);
}

static int compare_relocs(const void *a, const void *b)
{
	const struct mips_reloc *ra = a, *rb = b;

	return ra->offset - rb->offset;
}

int main(int argc, char *argv[])
{
	unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries;
	size_t rel_size, rel_actual_size;
	const char *shstrtab, *sh_name, *rel_pfx;
	int (*parse_fn)(const void *rel);
	uint8_t *buf_start, *buf;
	const Elf32_Ehdr *ehdr32;
	const Elf64_Ehdr *ehdr64;
	uintptr_t sh_offset;
	Elf32_Shdr *shdr32;
	Elf64_Shdr *shdr64;
	struct stat st;
	int err, fd;
	void *elf;
	bool skip;

	fd = open(argv[1], O_RDWR);
	if (fd == -1) {
		fprintf(stderr, "Unable to open input file %s\n", argv[1]);
		err = errno;
		goto out_ret;
	}

	err = fstat(fd, &st);
	if (err) {
		fprintf(stderr, "Unable to fstat() input file\n");
		goto out_close_fd;
	}

	elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
	if (elf == MAP_FAILED) {
		fprintf(stderr, "Unable to mmap() input file\n");
		err = errno;
		goto out_close_fd;
	}

	ehdr32 = elf;
	ehdr64 = elf;

	if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) {
		fprintf(stderr, "Input file is not an ELF\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) {
		fprintf(stderr, "Unrecognised ELF version\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	switch (ehdr32->e_ident[EI_CLASS]) {
	case ELFCLASS32:
		is_64 = false;
		break;
	case ELFCLASS64:
		is_64 = true;
		break;
	default:
		fprintf(stderr, "Unrecognised ELF class\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	switch (ehdr32->e_ident[EI_DATA]) {
	case ELFDATA2LSB:
		is_be = false;
		break;
	case ELFDATA2MSB:
		is_be = true;
		break;
	default:
		fprintf(stderr, "Unrecognised ELF data encoding\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	if (ehdr_field(e_type) != ET_EXEC) {
		fprintf(stderr, "Input ELF is not an executable\n");
		printf("type 0x%lx\n", ehdr_field(e_type));
		err = -EINVAL;
		goto out_free_relocs;
	}

	if (ehdr_field(e_machine) != EM_MIPS) {
		fprintf(stderr, "Input ELF does not target MIPS\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	shdr32 = elf + ehdr_field(e_shoff);
	shdr64 = elf + ehdr_field(e_shoff);
	shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset);

	i_rel_shdr = UINT_MAX;
	for (i = 0; i < ehdr_field(e_shnum); i++) {
		sh_name = shstr(shdr_field(i, sh_name));

		if (!strcmp(sh_name, ".data.reloc")) {
			i_rel_shdr = i;
			continue;
		}

		if (!strcmp(sh_name, ".text")) {
			text_base = shdr_field(i, sh_addr);
			continue;
		}
	}
	if (i_rel_shdr == UINT_MAX) {
		fprintf(stderr, "Unable to find .rel section\n");
		err = -EINVAL;
		goto out_free_relocs;
	}
	if (!text_base) {
		fprintf(stderr, "Unable to find .text base address\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	rel_pfx = is_64 ? ".rela." : ".rel.";

	for (i = 0; i < ehdr_field(e_shnum); i++) {
		sh_type = shdr_field(i, sh_type);
		if ((sh_type != SHT_REL) && (sh_type != SHT_RELA))
			continue;

		sh_name = shstr(shdr_field(i, sh_name));
		if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) {
			if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn"))
				fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name);
			continue;
		}

		/*
		 * Skip reloc sections which either don't correspond to another
		 * section in the ELF, or whose corresponding section isn't
		 * loaded as part of the U-Boot binary (ie. doesn't have the
		 * alloc flags set).
		 */
		skip = true;
		for (j = 0; j < ehdr_field(e_shnum); j++) {
			if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name))))
				continue;

			skip = !(shdr_field(j, sh_flags) & SHF_ALLOC);
			break;
		}
		if (skip)
			continue;

		sh_offset = shdr_field(i, sh_offset);
		sh_entsize = shdr_field(i, sh_entsize);
		sh_entries = shdr_field(i, sh_size) / sh_entsize;

		if (sh_type == SHT_REL) {
			if (is_64) {
				fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n");
				err = -EINVAL;
				goto out_free_relocs;
			} else {
				parse_fn = parse_mips32_rel;
			}
		} else {
			if (is_64) {
				parse_fn = parse_mips64_rela;
			} else {
				fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n");
				err = -EINVAL;
				goto out_free_relocs;
			}
		}

		for (j = 0; j < sh_entries; j++) {
			err = parse_fn(elf + sh_offset + (j * sh_entsize));
			if (err)
				goto out_free_relocs;
		}
	}

	if (!relocs) {
		fprintf(stderr, "No relocs was found. Try to configure linker with --emit-relocs\n");
		err = -EINVAL;
		goto out_free_relocs;
	}

	/* Sort relocs in ascending order of offset */
	qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs);

	/* Make reloc offsets relative to their predecessor */
	for (i = relocs_idx - 1; i > 0; i--) {
		relocs[i].offset -= relocs[i - 1].offset;
	}

	/* Write the relocations to the .rel section */
	buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset);
	for (i = 0; i < relocs_idx; i++) {
		output_uint(&buf, relocs[i].type);
		output_uint(&buf, relocs[i].offset >> 2);
	}

	/* Write a terminating R_MIPS_NONE (0) */
	output_uint(&buf, R_MIPS_NONE);

	/* Ensure the relocs didn't overflow the .rel section */
	rel_size = shdr_field(i_rel_shdr, sh_size);
	rel_actual_size = buf - buf_start;
	if (rel_actual_size > rel_size) {
		fprintf(stderr, "Relocations overflow available space of 0x%lx (required 0x%lx)!\n",
			rel_size, rel_actual_size);
		fprintf(stderr, "Please adjust CONFIG_MIPS_RELOCATION_TABLE_SIZE to at least 0x%lx\n",
			(rel_actual_size + 0x100) & ~0xFF);
		err = -ENOMEM;
		goto out_free_relocs;
	}

	/* Make sure data is written back to the file */
	err = msync(elf, st.st_size, MS_SYNC);
	if (err) {
		fprintf(stderr, "Failed to msync: %d\n", errno);
		goto out_free_relocs;
	}

out_free_relocs:
	free(relocs);
	munmap(elf, st.st_size);
out_close_fd:
	close(fd);
out_ret:
	return err;
}