1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * MIPS Relocation Data Generator
4 *
5 * Copyright (c) 2017 Imagination Technologies Ltd.
6 */
7
8 #include <assert.h>
9 #include <elf.h>
10 #include <errno.h>
11 #include <fcntl.h>
12 #include <limits.h>
13 #include <stdbool.h>
14 #include <stdio.h>
15 #include <stdlib.h>
16 #include <sys/mman.h>
17 #include <sys/stat.h>
18 #include <unistd.h>
19
20 #include <asm/relocs.h>
21
22 #define hdr_field(pfx, idx, field) ({ \
23 uint64_t _val; \
24 unsigned int _size; \
25 \
26 if (is_64) { \
27 _val = pfx##hdr64[idx].field; \
28 _size = sizeof(pfx##hdr64[0].field); \
29 } else { \
30 _val = pfx##hdr32[idx].field; \
31 _size = sizeof(pfx##hdr32[0].field); \
32 } \
33 \
34 switch (_size) { \
35 case 1: \
36 break; \
37 case 2: \
38 _val = is_be ? be16toh(_val) : le16toh(_val); \
39 break; \
40 case 4: \
41 _val = is_be ? be32toh(_val) : le32toh(_val); \
42 break; \
43 case 8: \
44 _val = is_be ? be64toh(_val) : le64toh(_val); \
45 break; \
46 } \
47 \
48 _val; \
49 })
50
51 #define set_hdr_field(pfx, idx, field, val) ({ \
52 uint64_t _val; \
53 unsigned int _size; \
54 \
55 if (is_64) \
56 _size = sizeof(pfx##hdr64[0].field); \
57 else \
58 _size = sizeof(pfx##hdr32[0].field); \
59 \
60 switch (_size) { \
61 case 1: \
62 _val = val; \
63 break; \
64 case 2: \
65 _val = is_be ? htobe16(val) : htole16(val); \
66 break; \
67 case 4: \
68 _val = is_be ? htobe32(val) : htole32(val); \
69 break; \
70 case 8: \
71 _val = is_be ? htobe64(val) : htole64(val); \
72 break; \
73 default: \
74 /* We should never reach here */ \
75 _val = 0; \
76 assert(0); \
77 break; \
78 } \
79 \
80 if (is_64) \
81 pfx##hdr64[idx].field = _val; \
82 else \
83 pfx##hdr32[idx].field = _val; \
84 })
85
86 #define ehdr_field(field) \
87 hdr_field(e, 0, field)
88 #define phdr_field(idx, field) \
89 hdr_field(p, idx, field)
90 #define shdr_field(idx, field) \
91 hdr_field(s, idx, field)
92
93 #define set_phdr_field(idx, field, val) \
94 set_hdr_field(p, idx, field, val)
95 #define set_shdr_field(idx, field, val) \
96 set_hdr_field(s, idx, field, val)
97
98 #define shstr(idx) (&shstrtab[idx])
99
100 bool is_64, is_be;
101 uint64_t text_base;
102
103 struct mips_reloc {
104 uint8_t type;
105 uint64_t offset;
106 } *relocs;
107 size_t relocs_sz, relocs_idx;
108
add_reloc(unsigned int type,uint64_t off)109 static int add_reloc(unsigned int type, uint64_t off)
110 {
111 struct mips_reloc *new;
112 size_t new_sz;
113
114 switch (type) {
115 case R_MIPS_NONE:
116 case R_MIPS_LO16:
117 case R_MIPS_PC16:
118 case R_MIPS_HIGHER:
119 case R_MIPS_HIGHEST:
120 case R_MIPS_PC21_S2:
121 case R_MIPS_PC26_S2:
122 /* Skip these relocs */
123 return 0;
124
125 default:
126 break;
127 }
128
129 if (relocs_idx == relocs_sz) {
130 new_sz = relocs_sz ? relocs_sz * 2 : 128;
131 new = realloc(relocs, new_sz * sizeof(*relocs));
132 if (!new) {
133 fprintf(stderr, "Out of memory\n");
134 return -ENOMEM;
135 }
136
137 relocs = new;
138 relocs_sz = new_sz;
139 }
140
141 relocs[relocs_idx++] = (struct mips_reloc){
142 .type = type,
143 .offset = off,
144 };
145
146 return 0;
147 }
148
parse_mips32_rel(const void * _rel)149 static int parse_mips32_rel(const void *_rel)
150 {
151 const Elf32_Rel *rel = _rel;
152 uint32_t off, type;
153
154 off = is_be ? be32toh(rel->r_offset) : le32toh(rel->r_offset);
155 off -= text_base;
156
157 type = is_be ? be32toh(rel->r_info) : le32toh(rel->r_info);
158 type = ELF32_R_TYPE(type);
159
160 return add_reloc(type, off);
161 }
162
parse_mips64_rela(const void * _rel)163 static int parse_mips64_rela(const void *_rel)
164 {
165 const Elf64_Rela *rel = _rel;
166 uint64_t off, type;
167
168 off = is_be ? be64toh(rel->r_offset) : le64toh(rel->r_offset);
169 off -= text_base;
170
171 type = rel->r_info >> (64 - 8);
172
173 return add_reloc(type, off);
174 }
175
output_uint(uint8_t ** buf,uint64_t val)176 static void output_uint(uint8_t **buf, uint64_t val)
177 {
178 uint64_t tmp;
179
180 do {
181 tmp = val & 0x7f;
182 val >>= 7;
183 tmp |= !!val << 7;
184 *(*buf)++ = tmp;
185 } while (val);
186 }
187
compare_relocs(const void * a,const void * b)188 static int compare_relocs(const void *a, const void *b)
189 {
190 const struct mips_reloc *ra = a, *rb = b;
191
192 return ra->offset - rb->offset;
193 }
194
main(int argc,char * argv[])195 int main(int argc, char *argv[])
196 {
197 unsigned int i, j, i_rel_shdr, sh_type, sh_entsize, sh_entries;
198 size_t rel_size, rel_actual_size;
199 const char *shstrtab, *sh_name, *rel_pfx;
200 int (*parse_fn)(const void *rel);
201 uint8_t *buf_start, *buf;
202 const Elf32_Ehdr *ehdr32;
203 const Elf64_Ehdr *ehdr64;
204 uintptr_t sh_offset;
205 Elf32_Shdr *shdr32;
206 Elf64_Shdr *shdr64;
207 struct stat st;
208 int err, fd;
209 void *elf;
210 bool skip;
211
212 fd = open(argv[1], O_RDWR);
213 if (fd == -1) {
214 fprintf(stderr, "Unable to open input file %s\n", argv[1]);
215 err = errno;
216 goto out_ret;
217 }
218
219 err = fstat(fd, &st);
220 if (err) {
221 fprintf(stderr, "Unable to fstat() input file\n");
222 goto out_close_fd;
223 }
224
225 elf = mmap(NULL, st.st_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
226 if (elf == MAP_FAILED) {
227 fprintf(stderr, "Unable to mmap() input file\n");
228 err = errno;
229 goto out_close_fd;
230 }
231
232 ehdr32 = elf;
233 ehdr64 = elf;
234
235 if (memcmp(&ehdr32->e_ident[EI_MAG0], ELFMAG, SELFMAG)) {
236 fprintf(stderr, "Input file is not an ELF\n");
237 err = -EINVAL;
238 goto out_free_relocs;
239 }
240
241 if (ehdr32->e_ident[EI_VERSION] != EV_CURRENT) {
242 fprintf(stderr, "Unrecognised ELF version\n");
243 err = -EINVAL;
244 goto out_free_relocs;
245 }
246
247 switch (ehdr32->e_ident[EI_CLASS]) {
248 case ELFCLASS32:
249 is_64 = false;
250 break;
251 case ELFCLASS64:
252 is_64 = true;
253 break;
254 default:
255 fprintf(stderr, "Unrecognised ELF class\n");
256 err = -EINVAL;
257 goto out_free_relocs;
258 }
259
260 switch (ehdr32->e_ident[EI_DATA]) {
261 case ELFDATA2LSB:
262 is_be = false;
263 break;
264 case ELFDATA2MSB:
265 is_be = true;
266 break;
267 default:
268 fprintf(stderr, "Unrecognised ELF data encoding\n");
269 err = -EINVAL;
270 goto out_free_relocs;
271 }
272
273 if (ehdr_field(e_type) != ET_EXEC) {
274 fprintf(stderr, "Input ELF is not an executable\n");
275 printf("type 0x%lx\n", ehdr_field(e_type));
276 err = -EINVAL;
277 goto out_free_relocs;
278 }
279
280 if (ehdr_field(e_machine) != EM_MIPS) {
281 fprintf(stderr, "Input ELF does not target MIPS\n");
282 err = -EINVAL;
283 goto out_free_relocs;
284 }
285
286 shdr32 = elf + ehdr_field(e_shoff);
287 shdr64 = elf + ehdr_field(e_shoff);
288 shstrtab = elf + shdr_field(ehdr_field(e_shstrndx), sh_offset);
289
290 i_rel_shdr = UINT_MAX;
291 for (i = 0; i < ehdr_field(e_shnum); i++) {
292 sh_name = shstr(shdr_field(i, sh_name));
293
294 if (!strcmp(sh_name, ".data.reloc")) {
295 i_rel_shdr = i;
296 continue;
297 }
298
299 if (!strcmp(sh_name, ".text")) {
300 text_base = shdr_field(i, sh_addr);
301 continue;
302 }
303 }
304 if (i_rel_shdr == UINT_MAX) {
305 fprintf(stderr, "Unable to find .rel section\n");
306 err = -EINVAL;
307 goto out_free_relocs;
308 }
309 if (!text_base) {
310 fprintf(stderr, "Unable to find .text base address\n");
311 err = -EINVAL;
312 goto out_free_relocs;
313 }
314
315 rel_pfx = is_64 ? ".rela." : ".rel.";
316
317 for (i = 0; i < ehdr_field(e_shnum); i++) {
318 sh_type = shdr_field(i, sh_type);
319 if ((sh_type != SHT_REL) && (sh_type != SHT_RELA))
320 continue;
321
322 sh_name = shstr(shdr_field(i, sh_name));
323 if (strncmp(sh_name, rel_pfx, strlen(rel_pfx))) {
324 if (strcmp(sh_name, ".rel") && strcmp(sh_name, ".rel.dyn"))
325 fprintf(stderr, "WARNING: Unexpected reloc section name '%s'\n", sh_name);
326 continue;
327 }
328
329 /*
330 * Skip reloc sections which either don't correspond to another
331 * section in the ELF, or whose corresponding section isn't
332 * loaded as part of the U-Boot binary (ie. doesn't have the
333 * alloc flags set).
334 */
335 skip = true;
336 for (j = 0; j < ehdr_field(e_shnum); j++) {
337 if (strcmp(&sh_name[strlen(rel_pfx) - 1], shstr(shdr_field(j, sh_name))))
338 continue;
339
340 skip = !(shdr_field(j, sh_flags) & SHF_ALLOC);
341 break;
342 }
343 if (skip)
344 continue;
345
346 sh_offset = shdr_field(i, sh_offset);
347 sh_entsize = shdr_field(i, sh_entsize);
348 sh_entries = shdr_field(i, sh_size) / sh_entsize;
349
350 if (sh_type == SHT_REL) {
351 if (is_64) {
352 fprintf(stderr, "REL-style reloc in MIPS64 ELF?\n");
353 err = -EINVAL;
354 goto out_free_relocs;
355 } else {
356 parse_fn = parse_mips32_rel;
357 }
358 } else {
359 if (is_64) {
360 parse_fn = parse_mips64_rela;
361 } else {
362 fprintf(stderr, "RELA-style reloc in MIPS32 ELF?\n");
363 err = -EINVAL;
364 goto out_free_relocs;
365 }
366 }
367
368 for (j = 0; j < sh_entries; j++) {
369 err = parse_fn(elf + sh_offset + (j * sh_entsize));
370 if (err)
371 goto out_free_relocs;
372 }
373 }
374
375 /* Sort relocs in ascending order of offset */
376 qsort(relocs, relocs_idx, sizeof(*relocs), compare_relocs);
377
378 /* Make reloc offsets relative to their predecessor */
379 for (i = relocs_idx - 1; i > 0; i--)
380 relocs[i].offset -= relocs[i - 1].offset;
381
382 /* Write the relocations to the .rel section */
383 buf = buf_start = elf + shdr_field(i_rel_shdr, sh_offset);
384 for (i = 0; i < relocs_idx; i++) {
385 output_uint(&buf, relocs[i].type);
386 output_uint(&buf, relocs[i].offset >> 2);
387 }
388
389 /* Write a terminating R_MIPS_NONE (0) */
390 output_uint(&buf, R_MIPS_NONE);
391
392 /* Ensure the relocs didn't overflow the .rel section */
393 rel_size = shdr_field(i_rel_shdr, sh_size);
394 rel_actual_size = buf - buf_start;
395 if (rel_actual_size > rel_size) {
396 fprintf(stderr, "Relocations overflow available space of 0x%lx (required 0x%lx)!\n",
397 rel_size, rel_actual_size);
398 fprintf(stderr, "Please adjust CONFIG_MIPS_RELOCATION_TABLE_SIZE to at least 0x%lx\n",
399 (rel_actual_size + 0x100) & ~0xFF);
400 err = -ENOMEM;
401 goto out_free_relocs;
402 }
403
404 /* Make sure data is written back to the file */
405 err = msync(elf, st.st_size, MS_SYNC);
406 if (err) {
407 fprintf(stderr, "Failed to msync: %d\n", errno);
408 goto out_free_relocs;
409 }
410
411 out_free_relocs:
412 free(relocs);
413 munmap(elf, st.st_size);
414 out_close_fd:
415 close(fd);
416 out_ret:
417 return err;
418 }
419