blob: 27d47308e00314427043e721b9bd92f5454a4665 [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
Paul Burtone94136b2017-07-25 15:07:03 +01009#include <assert.h>
Paul Burton703ec9d2017-06-19 11:53:47 -070010#include <elf.h>
11#include <errno.h>
12#include <fcntl.h>
13#include <limits.h>
Masahiro Yamadad2bf1152018-01-21 19:19:15 +090014#include <stdbool.h>
Paul Burton703ec9d2017-06-19 11:53:47 -070015#include <stdio.h>
16#include <stdlib.h>
17#include <sys/mman.h>
18#include <sys/stat.h>
19#include <unistd.h>
20
21#include <asm/relocs.h>
22
23#define hdr_field(pfx, idx, field) ({ \
24 uint64_t _val; \
25 unsigned int _size; \
26 \
27 if (is_64) { \
28 _val = pfx##hdr64[idx].field; \
29 _size = sizeof(pfx##hdr64[0].field); \
30 } else { \
31 _val = pfx##hdr32[idx].field; \
32 _size = sizeof(pfx##hdr32[0].field); \
33 } \
34 \
35 switch (_size) { \
36 case 1: \
37 break; \
38 case 2: \
39 _val = is_be ? be16toh(_val) : le16toh(_val); \
40 break; \
41 case 4: \
42 _val = is_be ? be32toh(_val) : le32toh(_val); \
43 break; \
44 case 8: \
45 _val = is_be ? be64toh(_val) : le64toh(_val); \
46 break; \
47 } \
48 \
49 _val; \
50})
51
52#define set_hdr_field(pfx, idx, field, val) ({ \
53 uint64_t _val; \
54 unsigned int _size; \
55 \
56 if (is_64) \
57 _size = sizeof(pfx##hdr64[0].field); \
58 else \
59 _size = sizeof(pfx##hdr32[0].field); \
60 \
61 switch (_size) { \
62 case 1: \
63 _val = val; \
64 break; \
65 case 2: \
66 _val = is_be ? htobe16(val) : htole16(val); \
67 break; \
68 case 4: \
69 _val = is_be ? htobe32(val) : htole32(val); \
70 break; \
71 case 8: \
72 _val = is_be ? htobe64(val) : htole64(val); \
73 break; \
Paul Burtone94136b2017-07-25 15:07:03 +010074 default: \
75 /* We should never reach here */ \
76 _val = 0; \
77 assert(0); \
78 break; \
Paul Burton703ec9d2017-06-19 11:53:47 -070079 } \
80 \
81 if (is_64) \
82 pfx##hdr64[idx].field = _val; \
83 else \
84 pfx##hdr32[idx].field = _val; \
85})
86
87#define ehdr_field(field) \
88 hdr_field(e, 0, field)
89#define phdr_field(idx, field) \
90 hdr_field(p, idx, field)
91#define shdr_field(idx, field) \
92 hdr_field(s, idx, field)
93
94#define set_phdr_field(idx, field, val) \
95 set_hdr_field(p, idx, field, val)
96#define set_shdr_field(idx, field, val) \
97 set_hdr_field(s, idx, field, val)
98
99#define shstr(idx) (&shstrtab[idx])
100
101bool is_64, is_be;
102uint64_t text_base;
103
104struct mips_reloc {
105 uint8_t type;
106 uint64_t offset;
107} *relocs;
108size_t relocs_sz, relocs_idx;
109
110static int add_reloc(unsigned int type, uint64_t off)
111{
112 struct mips_reloc *new;
113 size_t new_sz;
114
115 switch (type) {
116 case R_MIPS_NONE:
117 case R_MIPS_LO16:
118 case R_MIPS_PC16:
119 case R_MIPS_HIGHER:
120 case R_MIPS_HIGHEST:
121 case R_MIPS_PC21_S2:
122 case R_MIPS_PC26_S2:
123 /* Skip these relocs */
124 return 0;
125
126 default:
127 break;
128 }
129
130 if (relocs_idx == relocs_sz) {
131 new_sz = relocs_sz ? relocs_sz * 2 : 128;
132 new = realloc(relocs, new_sz * sizeof(*relocs));
133 if (!new) {
134 fprintf(stderr, "Out of memory\n");
135 return -ENOMEM;
136 }
137
138 relocs = new;
139 relocs_sz = new_sz;
140 }
141
142 relocs[relocs_idx++] = (struct mips_reloc){
143 .type = type,
144 .offset = off,
145 };
146
147 return 0;
148}
149
150static int parse_mips32_rel(const void *_rel)
151{
152 const Elf32_Rel *rel = _rel;
153 uint32_t off, type;
154
155 off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset);
156 off -= text_base;
157
158 type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info);
159 type = ELF32_R_TYPE(type);
160
161 return add_reloc(type, off);
162}
163
164static int parse_mips64_rela(const void *_rel)
165{
166 const Elf64_Rela *rel = _rel;
167 uint64_t off, type;
168
169 off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset);
170 off -= text_base;
171
172 type = rel->r_info >> (64 - 8);
173
174 return add_reloc(type, off);
175}
176
177static void output_uint(uint8_t **buf, uint64_t val)
178{
179 uint64_t tmp;
180
181 do {
182 tmp = val & 0x7f;
183 val >>= 7;
184 tmp |= !!val << 7;
185 *(*buf)++ = tmp;
186 } while (val);
187}
188
189static int compare_relocs(const void *a, const void *b)
190{
191 const struct mips_reloc *ra = a, *rb = b;
192
193 return ra->offset - rb->offset;
194}
195
196int main(int argc, char *argv[])
197{
198 unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries;
199 size_t rel_size, rel_actual_size, load_sz;
200 const char *shstrtab, *sh_name, *rel_pfx;
201 int (*parse_fn)(const void *rel);
202 uint8_t *buf_start, *buf;
203 const Elf32_Ehdr *ehdr32;
204 const Elf64_Ehdr *ehdr64;
205 uintptr_t sh_offset;
206 Elf32_Phdr *phdr32;
207 Elf64_Phdr *phdr64;
208 Elf32_Shdr *shdr32;
209 Elf64_Shdr *shdr64;
210 struct stat st;
211 int err, fd;
212 void *elf;
213 bool skip;
214
215 fd = open(argv[1], O_RDWR);
216 if (fd == -1) {
217 fprintf(stderr, "Unable to open input file %s\n", argv[1]);
218 err = errno;
219 goto out_ret;
220 }
221
222 err = fstat(fd, &st);
223 if (err) {
224 fprintf(stderr, "Unable to fstat() input file\n");
225 goto out_close_fd;
226 }
227
228 elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
229 if (elf == MAP_FAILED) {
230 fprintf(stderr, "Unable to mmap() input file\n");
231 err = errno;
232 goto out_close_fd;
233 }
234
235 ehdr32 = elf;
236 ehdr64 = elf;
237
238 if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) {
239 fprintf(stderr, "Input file is not an ELF\n");
240 err = -EINVAL;
241 goto out_free_relocs;
242 }
243
244 if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) {
245 fprintf(stderr, "Unrecognised ELF version\n");
246 err = -EINVAL;
247 goto out_free_relocs;
248 }
249
250 switch (ehdr32->e_ident[EI_CLASS]) {
251 case ELFCLASS32:
252 is_64 = false;
253 break;
254 case ELFCLASS64:
255 is_64 = true;
256 break;
257 default:
258 fprintf(stderr, "Unrecognised ELF class\n");
259 err = -EINVAL;
260 goto out_free_relocs;
261 }
262
263 switch (ehdr32->e_ident[EI_DATA]) {
264 case ELFDATA2LSB:
265 is_be = false;
266 break;
267 case ELFDATA2MSB:
268 is_be = true;
269 break;
270 default:
271 fprintf(stderr, "Unrecognised ELF data encoding\n");
272 err = -EINVAL;
273 goto out_free_relocs;
274 }
275
276 if (ehdr_field(e_type) != ET_EXEC) {
277 fprintf(stderr, "Input ELF is not an executable\n");
278 printf("type 0x%lx\n", ehdr_field(e_type));
279 err = -EINVAL;
280 goto out_free_relocs;
281 }
282
283 if (ehdr_field(e_machine) != EM_MIPS) {
284 fprintf(stderr, "Input ELF does not target MIPS\n");
285 err = -EINVAL;
286 goto out_free_relocs;
287 }
288
289 phdr32 = elf + ehdr_field(e_phoff);
290 phdr64 = elf + ehdr_field(e_phoff);
291 shdr32 = elf + ehdr_field(e_shoff);
292 shdr64 = elf + ehdr_field(e_shoff);
293 shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset);
294
295 i_rel_shdr = UINT_MAX;
296 for (i = 0; i < ehdr_field(e_shnum); i++) {
297 sh_name = shstr(shdr_field(i, sh_name));
298
299 if (!strcmp(sh_name, ".rel")) {
300 i_rel_shdr = i;
301 continue;
302 }
303
304 if (!strcmp(sh_name, ".text")) {
305 text_base = shdr_field(i, sh_addr);
306 continue;
307 }
308 }
309 if (i_rel_shdr == UINT_MAX) {
310 fprintf(stderr, "Unable to find .rel section\n");
311 err = -EINVAL;
312 goto out_free_relocs;
313 }
314 if (!text_base) {
315 fprintf(stderr, "Unable to find .text base address\n");
316 err = -EINVAL;
317 goto out_free_relocs;
318 }
319
320 rel_pfx = is_64 ? ".rela." : ".rel.";
321
322 for (i = 0; i < ehdr_field(e_shnum); i++) {
323 sh_type = shdr_field(i, sh_type);
324 if ((sh_type != SHT_REL) && (sh_type != SHT_RELA))
325 continue;
326
327 sh_name = shstr(shdr_field(i, sh_name));
328 if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) {
329 if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn"))
330 fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name);
331 continue;
332 }
333
334 /*
335 * Skip reloc sections which either don't correspond to another
336 * section in the ELF, or whose corresponding section isn't
337 * loaded as part of the U-Boot binary (ie. doesn't have the
338 * alloc flags set).
339 */
340 skip = true;
341 for (j = 0; j < ehdr_field(e_shnum); j++) {
342 if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name))))
343 continue;
344
345 skip = !(shdr_field(j, sh_flags) & SHF_ALLOC);
346 break;
347 }
348 if (skip)
349 continue;
350
351 sh_offset = shdr_field(i, sh_offset);
352 sh_entsize = shdr_field(i, sh_entsize);
353 sh_entries = shdr_field(i, sh_size) / sh_entsize;
354
355 if (sh_type == SHT_REL) {
356 if (is_64) {
357 fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n");
358 err = -EINVAL;
359 goto out_free_relocs;
360 } else {
361 parse_fn = parse_mips32_rel;
362 }
363 } else {
364 if (is_64) {
365 parse_fn = parse_mips64_rela;
366 } else {
367 fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n");
368 err = -EINVAL;
369 goto out_free_relocs;
370 }
371 }
372
373 for (j = 0; j < sh_entries; j++) {
374 err = parse_fn(elf + sh_offset + (j * sh_entsize));
375 if (err)
376 goto out_free_relocs;
377 }
378 }
379
380 /* Sort relocs in ascending order of offset */
381 qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs);
382
383 /* Make reloc offsets relative to their predecessor */
384 for (i = relocs_idx - 1; i > 0; i--)
385 relocs[i].offset -= relocs[i - 1].offset;
386
387 /* Write the relocations to the .rel section */
388 buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset);
389 for (i = 0; i < relocs_idx; i++) {
390 output_uint(&buf, relocs[i].type);
391 output_uint(&buf, relocs[i].offset >> 2);
392 }
393
394 /* Write a terminating R_MIPS_NONE (0) */
395 output_uint(&buf, R_MIPS_NONE);
396
397 /* Ensure the relocs didn't overflow the .rel section */
398 rel_size = shdr_field(i_rel_shdr, sh_size);
399 rel_actual_size = buf - buf_start;
400 if (rel_actual_size > rel_size) {
401 fprintf(stderr, "Relocs overflowed .rel section\n");
402 return -ENOMEM;
403 }
404
405 /* Update the .rel section's size */
406 set_shdr_field(i_rel_shdr, sh_size, rel_actual_size);
407
408 /* Shrink the PT_LOAD program header filesz (ie. shrink u-boot.bin) */
409 for (i = 0; i < ehdr_field(e_phnum); i++) {
410 if (phdr_field(i, p_type) != PT_LOAD)
411 continue;
412
413 load_sz = phdr_field(i, p_filesz);
414 load_sz -= rel_size - rel_actual_size;
415 set_phdr_field(i, p_filesz, load_sz);
416 break;
417 }
418
419 /* Make sure data is written back to the file */
420 err = msync(elf, st.st_size, MS_SYNC);
421 if (err) {
422 fprintf(stderr, "Failed to msync: %d\n", errno);
423 goto out_free_relocs;
424 }
425
426out_free_relocs:
427 free(relocs);
428 munmap(elf, st.st_size);
429out_close_fd:
430 close(fd);
431out_ret:
432 return err;
433}