blob: b690fa53c4be7137c256be1667f28c0646b1932f [file] [log] [blame]
Paul Burton703ec9d2017-06-19 11:53:47 -07001/*
2 * MIPS Relocation Data Generator
3 *
4 * Copyright (c) 2017 Imagination Technologies Ltd.
5 *
6 * SPDX-License-Identifier: GPL-2.0+
7 */
8
9#include <elf.h>
10#include <errno.h>
11#include <fcntl.h>
12#include <limits.h>
13#include <stdio.h>
14#include <stdlib.h>
15#include <sys/mman.h>
16#include <sys/stat.h>
17#include <unistd.h>
18
19#include <asm/relocs.h>
20
21#define hdr_field(pfx, idx, field) ({ \
22 uint64_t _val; \
23 unsigned int _size; \
24 \
25 if (is_64) { \
26 _val = pfx##hdr64[idx].field; \
27 _size = sizeof(pfx##hdr64[0].field); \
28 } else { \
29 _val = pfx##hdr32[idx].field; \
30 _size = sizeof(pfx##hdr32[0].field); \
31 } \
32 \
33 switch (_size) { \
34 case 1: \
35 break; \
36 case 2: \
37 _val = is_be ? be16toh(_val) : le16toh(_val); \
38 break; \
39 case 4: \
40 _val = is_be ? be32toh(_val) : le32toh(_val); \
41 break; \
42 case 8: \
43 _val = is_be ? be64toh(_val) : le64toh(_val); \
44 break; \
45 } \
46 \
47 _val; \
48})
49
50#define set_hdr_field(pfx, idx, field, val) ({ \
51 uint64_t _val; \
52 unsigned int _size; \
53 \
54 if (is_64) \
55 _size = sizeof(pfx##hdr64[0].field); \
56 else \
57 _size = sizeof(pfx##hdr32[0].field); \
58 \
59 switch (_size) { \
60 case 1: \
61 _val = val; \
62 break; \
63 case 2: \
64 _val = is_be ? htobe16(val) : htole16(val); \
65 break; \
66 case 4: \
67 _val = is_be ? htobe32(val) : htole32(val); \
68 break; \
69 case 8: \
70 _val = is_be ? htobe64(val) : htole64(val); \
71 break; \
72 } \
73 \
74 if (is_64) \
75 pfx##hdr64[idx].field = _val; \
76 else \
77 pfx##hdr32[idx].field = _val; \
78})
79
80#define ehdr_field(field) \
81 hdr_field(e, 0, field)
82#define phdr_field(idx, field) \
83 hdr_field(p, idx, field)
84#define shdr_field(idx, field) \
85 hdr_field(s, idx, field)
86
87#define set_phdr_field(idx, field, val) \
88 set_hdr_field(p, idx, field, val)
89#define set_shdr_field(idx, field, val) \
90 set_hdr_field(s, idx, field, val)
91
92#define shstr(idx) (&shstrtab[idx])
93
94bool is_64, is_be;
95uint64_t text_base;
96
97struct mips_reloc {
98 uint8_t type;
99 uint64_t offset;
100} *relocs;
101size_t relocs_sz, relocs_idx;
102
103static int add_reloc(unsigned int type, uint64_t off)
104{
105 struct mips_reloc *new;
106 size_t new_sz;
107
108 switch (type) {
109 case R_MIPS_NONE:
110 case R_MIPS_LO16:
111 case R_MIPS_PC16:
112 case R_MIPS_HIGHER:
113 case R_MIPS_HIGHEST:
114 case R_MIPS_PC21_S2:
115 case R_MIPS_PC26_S2:
116 /* Skip these relocs */
117 return 0;
118
119 default:
120 break;
121 }
122
123 if (relocs_idx == relocs_sz) {
124 new_sz = relocs_sz ? relocs_sz * 2 : 128;
125 new = realloc(relocs, new_sz * sizeof(*relocs));
126 if (!new) {
127 fprintf(stderr, "Out of memory\n");
128 return -ENOMEM;
129 }
130
131 relocs = new;
132 relocs_sz = new_sz;
133 }
134
135 relocs[relocs_idx++] = (struct mips_reloc){
136 .type = type,
137 .offset = off,
138 };
139
140 return 0;
141}
142
143static int parse_mips32_rel(const void *_rel)
144{
145 const Elf32_Rel *rel = _rel;
146 uint32_t off, type;
147
148 off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset);
149 off -= text_base;
150
151 type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info);
152 type = ELF32_R_TYPE(type);
153
154 return add_reloc(type, off);
155}
156
157static int parse_mips64_rela(const void *_rel)
158{
159 const Elf64_Rela *rel = _rel;
160 uint64_t off, type;
161
162 off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset);
163 off -= text_base;
164
165 type = rel->r_info >> (64 - 8);
166
167 return add_reloc(type, off);
168}
169
170static void output_uint(uint8_t **buf, uint64_t val)
171{
172 uint64_t tmp;
173
174 do {
175 tmp = val & 0x7f;
176 val >>= 7;
177 tmp |= !!val << 7;
178 *(*buf)++ = tmp;
179 } while (val);
180}
181
182static int compare_relocs(const void *a, const void *b)
183{
184 const struct mips_reloc *ra = a, *rb = b;
185
186 return ra->offset - rb->offset;
187}
188
189int main(int argc, char *argv[])
190{
191 unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries;
192 size_t rel_size, rel_actual_size, load_sz;
193 const char *shstrtab, *sh_name, *rel_pfx;
194 int (*parse_fn)(const void *rel);
195 uint8_t *buf_start, *buf;
196 const Elf32_Ehdr *ehdr32;
197 const Elf64_Ehdr *ehdr64;
198 uintptr_t sh_offset;
199 Elf32_Phdr *phdr32;
200 Elf64_Phdr *phdr64;
201 Elf32_Shdr *shdr32;
202 Elf64_Shdr *shdr64;
203 struct stat st;
204 int err, fd;
205 void *elf;
206 bool skip;
207
208 fd = open(argv[1], O_RDWR);
209 if (fd == -1) {
210 fprintf(stderr, "Unable to open input file %s\n", argv[1]);
211 err = errno;
212 goto out_ret;
213 }
214
215 err = fstat(fd, &st);
216 if (err) {
217 fprintf(stderr, "Unable to fstat() input file\n");
218 goto out_close_fd;
219 }
220
221 elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
222 if (elf == MAP_FAILED) {
223 fprintf(stderr, "Unable to mmap() input file\n");
224 err = errno;
225 goto out_close_fd;
226 }
227
228 ehdr32 = elf;
229 ehdr64 = elf;
230
231 if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) {
232 fprintf(stderr, "Input file is not an ELF\n");
233 err = -EINVAL;
234 goto out_free_relocs;
235 }
236
237 if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) {
238 fprintf(stderr, "Unrecognised ELF version\n");
239 err = -EINVAL;
240 goto out_free_relocs;
241 }
242
243 switch (ehdr32->e_ident[EI_CLASS]) {
244 case ELFCLASS32:
245 is_64 = false;
246 break;
247 case ELFCLASS64:
248 is_64 = true;
249 break;
250 default:
251 fprintf(stderr, "Unrecognised ELF class\n");
252 err = -EINVAL;
253 goto out_free_relocs;
254 }
255
256 switch (ehdr32->e_ident[EI_DATA]) {
257 case ELFDATA2LSB:
258 is_be = false;
259 break;
260 case ELFDATA2MSB:
261 is_be = true;
262 break;
263 default:
264 fprintf(stderr, "Unrecognised ELF data encoding\n");
265 err = -EINVAL;
266 goto out_free_relocs;
267 }
268
269 if (ehdr_field(e_type) != ET_EXEC) {
270 fprintf(stderr, "Input ELF is not an executable\n");
271 printf("type 0x%lx\n", ehdr_field(e_type));
272 err = -EINVAL;
273 goto out_free_relocs;
274 }
275
276 if (ehdr_field(e_machine) != EM_MIPS) {
277 fprintf(stderr, "Input ELF does not target MIPS\n");
278 err = -EINVAL;
279 goto out_free_relocs;
280 }
281
282 phdr32 = elf + ehdr_field(e_phoff);
283 phdr64 = elf + ehdr_field(e_phoff);
284 shdr32 = elf + ehdr_field(e_shoff);
285 shdr64 = elf + ehdr_field(e_shoff);
286 shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset);
287
288 i_rel_shdr = UINT_MAX;
289 for (i = 0; i < ehdr_field(e_shnum); i++) {
290 sh_name = shstr(shdr_field(i, sh_name));
291
292 if (!strcmp(sh_name, ".rel")) {
293 i_rel_shdr = i;
294 continue;
295 }
296
297 if (!strcmp(sh_name, ".text")) {
298 text_base = shdr_field(i, sh_addr);
299 continue;
300 }
301 }
302 if (i_rel_shdr == UINT_MAX) {
303 fprintf(stderr, "Unable to find .rel section\n");
304 err = -EINVAL;
305 goto out_free_relocs;
306 }
307 if (!text_base) {
308 fprintf(stderr, "Unable to find .text base address\n");
309 err = -EINVAL;
310 goto out_free_relocs;
311 }
312
313 rel_pfx = is_64 ? ".rela." : ".rel.";
314
315 for (i = 0; i < ehdr_field(e_shnum); i++) {
316 sh_type = shdr_field(i, sh_type);
317 if ((sh_type != SHT_REL) && (sh_type != SHT_RELA))
318 continue;
319
320 sh_name = shstr(shdr_field(i, sh_name));
321 if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) {
322 if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn"))
323 fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name);
324 continue;
325 }
326
327 /*
328 * Skip reloc sections which either don't correspond to another
329 * section in the ELF, or whose corresponding section isn't
330 * loaded as part of the U-Boot binary (ie. doesn't have the
331 * alloc flags set).
332 */
333 skip = true;
334 for (j = 0; j < ehdr_field(e_shnum); j++) {
335 if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name))))
336 continue;
337
338 skip = !(shdr_field(j, sh_flags) & SHF_ALLOC);
339 break;
340 }
341 if (skip)
342 continue;
343
344 sh_offset = shdr_field(i, sh_offset);
345 sh_entsize = shdr_field(i, sh_entsize);
346 sh_entries = shdr_field(i, sh_size) / sh_entsize;
347
348 if (sh_type == SHT_REL) {
349 if (is_64) {
350 fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n");
351 err = -EINVAL;
352 goto out_free_relocs;
353 } else {
354 parse_fn = parse_mips32_rel;
355 }
356 } else {
357 if (is_64) {
358 parse_fn = parse_mips64_rela;
359 } else {
360 fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n");
361 err = -EINVAL;
362 goto out_free_relocs;
363 }
364 }
365
366 for (j = 0; j < sh_entries; j++) {
367 err = parse_fn(elf + sh_offset + (j * sh_entsize));
368 if (err)
369 goto out_free_relocs;
370 }
371 }
372
373 /* Sort relocs in ascending order of offset */
374 qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs);
375
376 /* Make reloc offsets relative to their predecessor */
377 for (i = relocs_idx - 1; i > 0; i--)
378 relocs[i].offset -= relocs[i - 1].offset;
379
380 /* Write the relocations to the .rel section */
381 buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset);
382 for (i = 0; i < relocs_idx; i++) {
383 output_uint(&buf, relocs[i].type);
384 output_uint(&buf, relocs[i].offset >> 2);
385 }
386
387 /* Write a terminating R_MIPS_NONE (0) */
388 output_uint(&buf, R_MIPS_NONE);
389
390 /* Ensure the relocs didn't overflow the .rel section */
391 rel_size = shdr_field(i_rel_shdr, sh_size);
392 rel_actual_size = buf - buf_start;
393 if (rel_actual_size > rel_size) {
394 fprintf(stderr, "Relocs overflowed .rel section\n");
395 return -ENOMEM;
396 }
397
398 /* Update the .rel section's size */
399 set_shdr_field(i_rel_shdr, sh_size, rel_actual_size);
400
401 /* Shrink the PT_LOAD program header filesz (ie. shrink u-boot.bin) */
402 for (i = 0; i < ehdr_field(e_phnum); i++) {
403 if (phdr_field(i, p_type) != PT_LOAD)
404 continue;
405
406 load_sz = phdr_field(i, p_filesz);
407 load_sz -= rel_size - rel_actual_size;
408 set_phdr_field(i, p_filesz, load_sz);
409 break;
410 }
411
412 /* Make sure data is written back to the file */
413 err = msync(elf, st.st_size, MS_SYNC);
414 if (err) {
415 fprintf(stderr, "Failed to msync: %d\n", errno);
416 goto out_free_relocs;
417 }
418
419out_free_relocs:
420 free(relocs);
421 munmap(elf, st.st_size);
422out_close_fd:
423 close(fd);
424out_ret:
425 return err;
426}