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TOMOYO Linux Cross Reference
Linux/arch/x86/tools/relocs.c

Version: ~ [ linux-5.5-rc1 ] ~ [ linux-5.4.2 ] ~ [ linux-5.3.15 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.88 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.158 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.206 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.206 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.78 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
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  1 /* This is included from relocs_32/64.c */
  2 
  3 #define ElfW(type)              _ElfW(ELF_BITS, type)
  4 #define _ElfW(bits, type)       __ElfW(bits, type)
  5 #define __ElfW(bits, type)      Elf##bits##_##type
  6 
  7 #define Elf_Addr                ElfW(Addr)
  8 #define Elf_Ehdr                ElfW(Ehdr)
  9 #define Elf_Phdr                ElfW(Phdr)
 10 #define Elf_Shdr                ElfW(Shdr)
 11 #define Elf_Sym                 ElfW(Sym)
 12 
 13 static Elf_Ehdr ehdr;
 14 
 15 struct relocs {
 16         uint32_t        *offset;
 17         unsigned long   count;
 18         unsigned long   size;
 19 };
 20 
 21 static struct relocs relocs16;
 22 static struct relocs relocs32;
 23 #if ELF_BITS == 64
 24 static struct relocs relocs32neg;
 25 static struct relocs relocs64;
 26 #endif
 27 
 28 struct section {
 29         Elf_Shdr       shdr;
 30         struct section *link;
 31         Elf_Sym        *symtab;
 32         Elf_Rel        *reltab;
 33         char           *strtab;
 34 };
 35 static struct section *secs;
 36 
 37 static const char * const sym_regex_kernel[S_NSYMTYPES] = {
 38 /*
 39  * Following symbols have been audited. There values are constant and do
 40  * not change if bzImage is loaded at a different physical address than
 41  * the address for which it has been compiled. Don't warn user about
 42  * absolute relocations present w.r.t these symbols.
 43  */
 44         [S_ABS] =
 45         "^(xen_irq_disable_direct_reloc$|"
 46         "xen_save_fl_direct_reloc$|"
 47         "VDSO|"
 48         "__crc_)",
 49 
 50 /*
 51  * These symbols are known to be relative, even if the linker marks them
 52  * as absolute (typically defined outside any section in the linker script.)
 53  */
 54         [S_REL] =
 55         "^(__init_(begin|end)|"
 56         "__x86_cpu_dev_(start|end)|"
 57         "(__parainstructions|__alt_instructions)(|_end)|"
 58         "(__iommu_table|__apicdrivers|__smp_locks)(|_end)|"
 59         "__(start|end)_pci_.*|"
 60         "__(start|end)_builtin_fw|"
 61         "__(start|stop)___ksymtab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
 62         "__(start|stop)___kcrctab(|_gpl|_unused|_unused_gpl|_gpl_future)|"
 63         "__(start|stop)___param|"
 64         "__(start|stop)___modver|"
 65         "__(start|stop)___bug_table|"
 66         "__tracedata_(start|end)|"
 67         "__(start|stop)_notes|"
 68         "__end_rodata|"
 69         "__initramfs_start|"
 70         "(jiffies|jiffies_64)|"
 71 #if ELF_BITS == 64
 72         "__per_cpu_load|"
 73         "init_per_cpu__.*|"
 74         "__end_rodata_hpage_align|"
 75 #endif
 76         "__vvar_page|"
 77         "_end)$"
 78 };
 79 
 80 
 81 static const char * const sym_regex_realmode[S_NSYMTYPES] = {
 82 /*
 83  * These symbols are known to be relative, even if the linker marks them
 84  * as absolute (typically defined outside any section in the linker script.)
 85  */
 86         [S_REL] =
 87         "^pa_",
 88 
 89 /*
 90  * These are 16-bit segment symbols when compiling 16-bit code.
 91  */
 92         [S_SEG] =
 93         "^real_mode_seg$",
 94 
 95 /*
 96  * These are offsets belonging to segments, as opposed to linear addresses,
 97  * when compiling 16-bit code.
 98  */
 99         [S_LIN] =
100         "^pa_",
101 };
102 
103 static const char * const *sym_regex;
104 
105 static regex_t sym_regex_c[S_NSYMTYPES];
106 static int is_reloc(enum symtype type, const char *sym_name)
107 {
108         return sym_regex[type] &&
109                 !regexec(&sym_regex_c[type], sym_name, 0, NULL, 0);
110 }
111 
112 static void regex_init(int use_real_mode)
113 {
114         char errbuf[128];
115         int err;
116         int i;
117 
118         if (use_real_mode)
119                 sym_regex = sym_regex_realmode;
120         else
121                 sym_regex = sym_regex_kernel;
122 
123         for (i = 0; i < S_NSYMTYPES; i++) {
124                 if (!sym_regex[i])
125                         continue;
126 
127                 err = regcomp(&sym_regex_c[i], sym_regex[i],
128                               REG_EXTENDED|REG_NOSUB);
129 
130                 if (err) {
131                         regerror(err, &sym_regex_c[i], errbuf, sizeof errbuf);
132                         die("%s", errbuf);
133                 }
134         }
135 }
136 
137 static const char *sym_type(unsigned type)
138 {
139         static const char *type_name[] = {
140 #define SYM_TYPE(X) [X] = #X
141                 SYM_TYPE(STT_NOTYPE),
142                 SYM_TYPE(STT_OBJECT),
143                 SYM_TYPE(STT_FUNC),
144                 SYM_TYPE(STT_SECTION),
145                 SYM_TYPE(STT_FILE),
146                 SYM_TYPE(STT_COMMON),
147                 SYM_TYPE(STT_TLS),
148 #undef SYM_TYPE
149         };
150         const char *name = "unknown sym type name";
151         if (type < ARRAY_SIZE(type_name)) {
152                 name = type_name[type];
153         }
154         return name;
155 }
156 
157 static const char *sym_bind(unsigned bind)
158 {
159         static const char *bind_name[] = {
160 #define SYM_BIND(X) [X] = #X
161                 SYM_BIND(STB_LOCAL),
162                 SYM_BIND(STB_GLOBAL),
163                 SYM_BIND(STB_WEAK),
164 #undef SYM_BIND
165         };
166         const char *name = "unknown sym bind name";
167         if (bind < ARRAY_SIZE(bind_name)) {
168                 name = bind_name[bind];
169         }
170         return name;
171 }
172 
173 static const char *sym_visibility(unsigned visibility)
174 {
175         static const char *visibility_name[] = {
176 #define SYM_VISIBILITY(X) [X] = #X
177                 SYM_VISIBILITY(STV_DEFAULT),
178                 SYM_VISIBILITY(STV_INTERNAL),
179                 SYM_VISIBILITY(STV_HIDDEN),
180                 SYM_VISIBILITY(STV_PROTECTED),
181 #undef SYM_VISIBILITY
182         };
183         const char *name = "unknown sym visibility name";
184         if (visibility < ARRAY_SIZE(visibility_name)) {
185                 name = visibility_name[visibility];
186         }
187         return name;
188 }
189 
190 static const char *rel_type(unsigned type)
191 {
192         static const char *type_name[] = {
193 #define REL_TYPE(X) [X] = #X
194 #if ELF_BITS == 64
195                 REL_TYPE(R_X86_64_NONE),
196                 REL_TYPE(R_X86_64_64),
197                 REL_TYPE(R_X86_64_PC32),
198                 REL_TYPE(R_X86_64_GOT32),
199                 REL_TYPE(R_X86_64_PLT32),
200                 REL_TYPE(R_X86_64_COPY),
201                 REL_TYPE(R_X86_64_GLOB_DAT),
202                 REL_TYPE(R_X86_64_JUMP_SLOT),
203                 REL_TYPE(R_X86_64_RELATIVE),
204                 REL_TYPE(R_X86_64_GOTPCREL),
205                 REL_TYPE(R_X86_64_32),
206                 REL_TYPE(R_X86_64_32S),
207                 REL_TYPE(R_X86_64_16),
208                 REL_TYPE(R_X86_64_PC16),
209                 REL_TYPE(R_X86_64_8),
210                 REL_TYPE(R_X86_64_PC8),
211 #else
212                 REL_TYPE(R_386_NONE),
213                 REL_TYPE(R_386_32),
214                 REL_TYPE(R_386_PC32),
215                 REL_TYPE(R_386_GOT32),
216                 REL_TYPE(R_386_PLT32),
217                 REL_TYPE(R_386_COPY),
218                 REL_TYPE(R_386_GLOB_DAT),
219                 REL_TYPE(R_386_JMP_SLOT),
220                 REL_TYPE(R_386_RELATIVE),
221                 REL_TYPE(R_386_GOTOFF),
222                 REL_TYPE(R_386_GOTPC),
223                 REL_TYPE(R_386_8),
224                 REL_TYPE(R_386_PC8),
225                 REL_TYPE(R_386_16),
226                 REL_TYPE(R_386_PC16),
227 #endif
228 #undef REL_TYPE
229         };
230         const char *name = "unknown type rel type name";
231         if (type < ARRAY_SIZE(type_name) && type_name[type]) {
232                 name = type_name[type];
233         }
234         return name;
235 }
236 
237 static const char *sec_name(unsigned shndx)
238 {
239         const char *sec_strtab;
240         const char *name;
241         sec_strtab = secs[ehdr.e_shstrndx].strtab;
242         name = "<noname>";
243         if (shndx < ehdr.e_shnum) {
244                 name = sec_strtab + secs[shndx].shdr.sh_name;
245         }
246         else if (shndx == SHN_ABS) {
247                 name = "ABSOLUTE";
248         }
249         else if (shndx == SHN_COMMON) {
250                 name = "COMMON";
251         }
252         return name;
253 }
254 
255 static const char *sym_name(const char *sym_strtab, Elf_Sym *sym)
256 {
257         const char *name;
258         name = "<noname>";
259         if (sym->st_name) {
260                 name = sym_strtab + sym->st_name;
261         }
262         else {
263                 name = sec_name(sym->st_shndx);
264         }
265         return name;
266 }
267 
268 static Elf_Sym *sym_lookup(const char *symname)
269 {
270         int i;
271         for (i = 0; i < ehdr.e_shnum; i++) {
272                 struct section *sec = &secs[i];
273                 long nsyms;
274                 char *strtab;
275                 Elf_Sym *symtab;
276                 Elf_Sym *sym;
277 
278                 if (sec->shdr.sh_type != SHT_SYMTAB)
279                         continue;
280 
281                 nsyms = sec->shdr.sh_size/sizeof(Elf_Sym);
282                 symtab = sec->symtab;
283                 strtab = sec->link->strtab;
284 
285                 for (sym = symtab; --nsyms >= 0; sym++) {
286                         if (!sym->st_name)
287                                 continue;
288                         if (strcmp(symname, strtab + sym->st_name) == 0)
289                                 return sym;
290                 }
291         }
292         return 0;
293 }
294 
295 #if BYTE_ORDER == LITTLE_ENDIAN
296 #define le16_to_cpu(val) (val)
297 #define le32_to_cpu(val) (val)
298 #define le64_to_cpu(val) (val)
299 #endif
300 #if BYTE_ORDER == BIG_ENDIAN
301 #define le16_to_cpu(val) bswap_16(val)
302 #define le32_to_cpu(val) bswap_32(val)
303 #define le64_to_cpu(val) bswap_64(val)
304 #endif
305 
306 static uint16_t elf16_to_cpu(uint16_t val)
307 {
308         return le16_to_cpu(val);
309 }
310 
311 static uint32_t elf32_to_cpu(uint32_t val)
312 {
313         return le32_to_cpu(val);
314 }
315 
316 #define elf_half_to_cpu(x)      elf16_to_cpu(x)
317 #define elf_word_to_cpu(x)      elf32_to_cpu(x)
318 
319 #if ELF_BITS == 64
320 static uint64_t elf64_to_cpu(uint64_t val)
321 {
322         return le64_to_cpu(val);
323 }
324 #define elf_addr_to_cpu(x)      elf64_to_cpu(x)
325 #define elf_off_to_cpu(x)       elf64_to_cpu(x)
326 #define elf_xword_to_cpu(x)     elf64_to_cpu(x)
327 #else
328 #define elf_addr_to_cpu(x)      elf32_to_cpu(x)
329 #define elf_off_to_cpu(x)       elf32_to_cpu(x)
330 #define elf_xword_to_cpu(x)     elf32_to_cpu(x)
331 #endif
332 
333 static void read_ehdr(FILE *fp)
334 {
335         if (fread(&ehdr, sizeof(ehdr), 1, fp) != 1) {
336                 die("Cannot read ELF header: %s\n",
337                         strerror(errno));
338         }
339         if (memcmp(ehdr.e_ident, ELFMAG, SELFMAG) != 0) {
340                 die("No ELF magic\n");
341         }
342         if (ehdr.e_ident[EI_CLASS] != ELF_CLASS) {
343                 die("Not a %d bit executable\n", ELF_BITS);
344         }
345         if (ehdr.e_ident[EI_DATA] != ELFDATA2LSB) {
346                 die("Not a LSB ELF executable\n");
347         }
348         if (ehdr.e_ident[EI_VERSION] != EV_CURRENT) {
349                 die("Unknown ELF version\n");
350         }
351         /* Convert the fields to native endian */
352         ehdr.e_type      = elf_half_to_cpu(ehdr.e_type);
353         ehdr.e_machine   = elf_half_to_cpu(ehdr.e_machine);
354         ehdr.e_version   = elf_word_to_cpu(ehdr.e_version);
355         ehdr.e_entry     = elf_addr_to_cpu(ehdr.e_entry);
356         ehdr.e_phoff     = elf_off_to_cpu(ehdr.e_phoff);
357         ehdr.e_shoff     = elf_off_to_cpu(ehdr.e_shoff);
358         ehdr.e_flags     = elf_word_to_cpu(ehdr.e_flags);
359         ehdr.e_ehsize    = elf_half_to_cpu(ehdr.e_ehsize);
360         ehdr.e_phentsize = elf_half_to_cpu(ehdr.e_phentsize);
361         ehdr.e_phnum     = elf_half_to_cpu(ehdr.e_phnum);
362         ehdr.e_shentsize = elf_half_to_cpu(ehdr.e_shentsize);
363         ehdr.e_shnum     = elf_half_to_cpu(ehdr.e_shnum);
364         ehdr.e_shstrndx  = elf_half_to_cpu(ehdr.e_shstrndx);
365 
366         if ((ehdr.e_type != ET_EXEC) && (ehdr.e_type != ET_DYN)) {
367                 die("Unsupported ELF header type\n");
368         }
369         if (ehdr.e_machine != ELF_MACHINE) {
370                 die("Not for %s\n", ELF_MACHINE_NAME);
371         }
372         if (ehdr.e_version != EV_CURRENT) {
373                 die("Unknown ELF version\n");
374         }
375         if (ehdr.e_ehsize != sizeof(Elf_Ehdr)) {
376                 die("Bad Elf header size\n");
377         }
378         if (ehdr.e_phentsize != sizeof(Elf_Phdr)) {
379                 die("Bad program header entry\n");
380         }
381         if (ehdr.e_shentsize != sizeof(Elf_Shdr)) {
382                 die("Bad section header entry\n");
383         }
384         if (ehdr.e_shstrndx >= ehdr.e_shnum) {
385                 die("String table index out of bounds\n");
386         }
387 }
388 
389 static void read_shdrs(FILE *fp)
390 {
391         int i;
392         Elf_Shdr shdr;
393 
394         secs = calloc(ehdr.e_shnum, sizeof(struct section));
395         if (!secs) {
396                 die("Unable to allocate %d section headers\n",
397                     ehdr.e_shnum);
398         }
399         if (fseek(fp, ehdr.e_shoff, SEEK_SET) < 0) {
400                 die("Seek to %d failed: %s\n",
401                         ehdr.e_shoff, strerror(errno));
402         }
403         for (i = 0; i < ehdr.e_shnum; i++) {
404                 struct section *sec = &secs[i];
405                 if (fread(&shdr, sizeof shdr, 1, fp) != 1)
406                         die("Cannot read ELF section headers %d/%d: %s\n",
407                             i, ehdr.e_shnum, strerror(errno));
408                 sec->shdr.sh_name      = elf_word_to_cpu(shdr.sh_name);
409                 sec->shdr.sh_type      = elf_word_to_cpu(shdr.sh_type);
410                 sec->shdr.sh_flags     = elf_xword_to_cpu(shdr.sh_flags);
411                 sec->shdr.sh_addr      = elf_addr_to_cpu(shdr.sh_addr);
412                 sec->shdr.sh_offset    = elf_off_to_cpu(shdr.sh_offset);
413                 sec->shdr.sh_size      = elf_xword_to_cpu(shdr.sh_size);
414                 sec->shdr.sh_link      = elf_word_to_cpu(shdr.sh_link);
415                 sec->shdr.sh_info      = elf_word_to_cpu(shdr.sh_info);
416                 sec->shdr.sh_addralign = elf_xword_to_cpu(shdr.sh_addralign);
417                 sec->shdr.sh_entsize   = elf_xword_to_cpu(shdr.sh_entsize);
418                 if (sec->shdr.sh_link < ehdr.e_shnum)
419                         sec->link = &secs[sec->shdr.sh_link];
420         }
421 
422 }
423 
424 static void read_strtabs(FILE *fp)
425 {
426         int i;
427         for (i = 0; i < ehdr.e_shnum; i++) {
428                 struct section *sec = &secs[i];
429                 if (sec->shdr.sh_type != SHT_STRTAB) {
430                         continue;
431                 }
432                 sec->strtab = malloc(sec->shdr.sh_size);
433                 if (!sec->strtab) {
434                         die("malloc of %d bytes for strtab failed\n",
435                                 sec->shdr.sh_size);
436                 }
437                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
438                         die("Seek to %d failed: %s\n",
439                                 sec->shdr.sh_offset, strerror(errno));
440                 }
441                 if (fread(sec->strtab, 1, sec->shdr.sh_size, fp)
442                     != sec->shdr.sh_size) {
443                         die("Cannot read symbol table: %s\n",
444                                 strerror(errno));
445                 }
446         }
447 }
448 
449 static void read_symtabs(FILE *fp)
450 {
451         int i,j;
452         for (i = 0; i < ehdr.e_shnum; i++) {
453                 struct section *sec = &secs[i];
454                 if (sec->shdr.sh_type != SHT_SYMTAB) {
455                         continue;
456                 }
457                 sec->symtab = malloc(sec->shdr.sh_size);
458                 if (!sec->symtab) {
459                         die("malloc of %d bytes for symtab failed\n",
460                                 sec->shdr.sh_size);
461                 }
462                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
463                         die("Seek to %d failed: %s\n",
464                                 sec->shdr.sh_offset, strerror(errno));
465                 }
466                 if (fread(sec->symtab, 1, sec->shdr.sh_size, fp)
467                     != sec->shdr.sh_size) {
468                         die("Cannot read symbol table: %s\n",
469                                 strerror(errno));
470                 }
471                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
472                         Elf_Sym *sym = &sec->symtab[j];
473                         sym->st_name  = elf_word_to_cpu(sym->st_name);
474                         sym->st_value = elf_addr_to_cpu(sym->st_value);
475                         sym->st_size  = elf_xword_to_cpu(sym->st_size);
476                         sym->st_shndx = elf_half_to_cpu(sym->st_shndx);
477                 }
478         }
479 }
480 
481 
482 static void read_relocs(FILE *fp)
483 {
484         int i,j;
485         for (i = 0; i < ehdr.e_shnum; i++) {
486                 struct section *sec = &secs[i];
487                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
488                         continue;
489                 }
490                 sec->reltab = malloc(sec->shdr.sh_size);
491                 if (!sec->reltab) {
492                         die("malloc of %d bytes for relocs failed\n",
493                                 sec->shdr.sh_size);
494                 }
495                 if (fseek(fp, sec->shdr.sh_offset, SEEK_SET) < 0) {
496                         die("Seek to %d failed: %s\n",
497                                 sec->shdr.sh_offset, strerror(errno));
498                 }
499                 if (fread(sec->reltab, 1, sec->shdr.sh_size, fp)
500                     != sec->shdr.sh_size) {
501                         die("Cannot read symbol table: %s\n",
502                                 strerror(errno));
503                 }
504                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
505                         Elf_Rel *rel = &sec->reltab[j];
506                         rel->r_offset = elf_addr_to_cpu(rel->r_offset);
507                         rel->r_info   = elf_xword_to_cpu(rel->r_info);
508 #if (SHT_REL_TYPE == SHT_RELA)
509                         rel->r_addend = elf_xword_to_cpu(rel->r_addend);
510 #endif
511                 }
512         }
513 }
514 
515 
516 static void print_absolute_symbols(void)
517 {
518         int i;
519         const char *format;
520 
521         if (ELF_BITS == 64)
522                 format = "%5d %016"PRIx64" %5"PRId64" %10s %10s %12s %s\n";
523         else
524                 format = "%5d %08"PRIx32"  %5"PRId32" %10s %10s %12s %s\n";
525 
526         printf("Absolute symbols\n");
527         printf(" Num:    Value Size  Type       Bind        Visibility  Name\n");
528         for (i = 0; i < ehdr.e_shnum; i++) {
529                 struct section *sec = &secs[i];
530                 char *sym_strtab;
531                 int j;
532 
533                 if (sec->shdr.sh_type != SHT_SYMTAB) {
534                         continue;
535                 }
536                 sym_strtab = sec->link->strtab;
537                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Sym); j++) {
538                         Elf_Sym *sym;
539                         const char *name;
540                         sym = &sec->symtab[j];
541                         name = sym_name(sym_strtab, sym);
542                         if (sym->st_shndx != SHN_ABS) {
543                                 continue;
544                         }
545                         printf(format,
546                                 j, sym->st_value, sym->st_size,
547                                 sym_type(ELF_ST_TYPE(sym->st_info)),
548                                 sym_bind(ELF_ST_BIND(sym->st_info)),
549                                 sym_visibility(ELF_ST_VISIBILITY(sym->st_other)),
550                                 name);
551                 }
552         }
553         printf("\n");
554 }
555 
556 static void print_absolute_relocs(void)
557 {
558         int i, printed = 0;
559         const char *format;
560 
561         if (ELF_BITS == 64)
562                 format = "%016"PRIx64" %016"PRIx64" %10s %016"PRIx64"  %s\n";
563         else
564                 format = "%08"PRIx32" %08"PRIx32" %10s %08"PRIx32"  %s\n";
565 
566         for (i = 0; i < ehdr.e_shnum; i++) {
567                 struct section *sec = &secs[i];
568                 struct section *sec_applies, *sec_symtab;
569                 char *sym_strtab;
570                 Elf_Sym *sh_symtab;
571                 int j;
572                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
573                         continue;
574                 }
575                 sec_symtab  = sec->link;
576                 sec_applies = &secs[sec->shdr.sh_info];
577                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
578                         continue;
579                 }
580                 sh_symtab  = sec_symtab->symtab;
581                 sym_strtab = sec_symtab->link->strtab;
582                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
583                         Elf_Rel *rel;
584                         Elf_Sym *sym;
585                         const char *name;
586                         rel = &sec->reltab[j];
587                         sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
588                         name = sym_name(sym_strtab, sym);
589                         if (sym->st_shndx != SHN_ABS) {
590                                 continue;
591                         }
592 
593                         /* Absolute symbols are not relocated if bzImage is
594                          * loaded at a non-compiled address. Display a warning
595                          * to user at compile time about the absolute
596                          * relocations present.
597                          *
598                          * User need to audit the code to make sure
599                          * some symbols which should have been section
600                          * relative have not become absolute because of some
601                          * linker optimization or wrong programming usage.
602                          *
603                          * Before warning check if this absolute symbol
604                          * relocation is harmless.
605                          */
606                         if (is_reloc(S_ABS, name) || is_reloc(S_REL, name))
607                                 continue;
608 
609                         if (!printed) {
610                                 printf("WARNING: Absolute relocations"
611                                         " present\n");
612                                 printf("Offset     Info     Type     Sym.Value "
613                                         "Sym.Name\n");
614                                 printed = 1;
615                         }
616 
617                         printf(format,
618                                 rel->r_offset,
619                                 rel->r_info,
620                                 rel_type(ELF_R_TYPE(rel->r_info)),
621                                 sym->st_value,
622                                 name);
623                 }
624         }
625 
626         if (printed)
627                 printf("\n");
628 }
629 
630 static void add_reloc(struct relocs *r, uint32_t offset)
631 {
632         if (r->count == r->size) {
633                 unsigned long newsize = r->size + 50000;
634                 void *mem = realloc(r->offset, newsize * sizeof(r->offset[0]));
635 
636                 if (!mem)
637                         die("realloc of %ld entries for relocs failed\n",
638                                 newsize);
639                 r->offset = mem;
640                 r->size = newsize;
641         }
642         r->offset[r->count++] = offset;
643 }
644 
645 static void walk_relocs(int (*process)(struct section *sec, Elf_Rel *rel,
646                         Elf_Sym *sym, const char *symname))
647 {
648         int i;
649         /* Walk through the relocations */
650         for (i = 0; i < ehdr.e_shnum; i++) {
651                 char *sym_strtab;
652                 Elf_Sym *sh_symtab;
653                 struct section *sec_applies, *sec_symtab;
654                 int j;
655                 struct section *sec = &secs[i];
656 
657                 if (sec->shdr.sh_type != SHT_REL_TYPE) {
658                         continue;
659                 }
660                 sec_symtab  = sec->link;
661                 sec_applies = &secs[sec->shdr.sh_info];
662                 if (!(sec_applies->shdr.sh_flags & SHF_ALLOC)) {
663                         continue;
664                 }
665                 sh_symtab = sec_symtab->symtab;
666                 sym_strtab = sec_symtab->link->strtab;
667                 for (j = 0; j < sec->shdr.sh_size/sizeof(Elf_Rel); j++) {
668                         Elf_Rel *rel = &sec->reltab[j];
669                         Elf_Sym *sym = &sh_symtab[ELF_R_SYM(rel->r_info)];
670                         const char *symname = sym_name(sym_strtab, sym);
671 
672                         process(sec, rel, sym, symname);
673                 }
674         }
675 }
676 
677 /*
678  * The .data..percpu section is a special case for x86_64 SMP kernels.
679  * It is used to initialize the actual per_cpu areas and to provide
680  * definitions for the per_cpu variables that correspond to their offsets
681  * within the percpu area. Since the values of all of the symbols need
682  * to be offsets from the start of the per_cpu area the virtual address
683  * (sh_addr) of .data..percpu is 0 in SMP kernels.
684  *
685  * This means that:
686  *
687  *      Relocations that reference symbols in the per_cpu area do not
688  *      need further relocation (since the value is an offset relative
689  *      to the start of the per_cpu area that does not change).
690  *
691  *      Relocations that apply to the per_cpu area need to have their
692  *      offset adjusted by by the value of __per_cpu_load to make them
693  *      point to the correct place in the loaded image (because the
694  *      virtual address of .data..percpu is 0).
695  *
696  * For non SMP kernels .data..percpu is linked as part of the normal
697  * kernel data and does not require special treatment.
698  *
699  */
700 static int per_cpu_shndx        = -1;
701 static Elf_Addr per_cpu_load_addr;
702 
703 static void percpu_init(void)
704 {
705         int i;
706         for (i = 0; i < ehdr.e_shnum; i++) {
707                 ElfW(Sym) *sym;
708                 if (strcmp(sec_name(i), ".data..percpu"))
709                         continue;
710 
711                 if (secs[i].shdr.sh_addr != 0)  /* non SMP kernel */
712                         return;
713 
714                 sym = sym_lookup("__per_cpu_load");
715                 if (!sym)
716                         die("can't find __per_cpu_load\n");
717 
718                 per_cpu_shndx = i;
719                 per_cpu_load_addr = sym->st_value;
720                 return;
721         }
722 }
723 
724 #if ELF_BITS == 64
725 
726 /*
727  * Check to see if a symbol lies in the .data..percpu section.
728  *
729  * The linker incorrectly associates some symbols with the
730  * .data..percpu section so we also need to check the symbol
731  * name to make sure that we classify the symbol correctly.
732  *
733  * The GNU linker incorrectly associates:
734  *      __init_begin
735  *      __per_cpu_load
736  *
737  * The "gold" linker incorrectly associates:
738  *      init_per_cpu__irq_stack_union
739  *      init_per_cpu__gdt_page
740  */
741 static int is_percpu_sym(ElfW(Sym) *sym, const char *symname)
742 {
743         return (sym->st_shndx == per_cpu_shndx) &&
744                 strcmp(symname, "__init_begin") &&
745                 strcmp(symname, "__per_cpu_load") &&
746                 strncmp(symname, "init_per_cpu_", 13);
747 }
748 
749 
750 static int do_reloc64(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
751                       const char *symname)
752 {
753         unsigned r_type = ELF64_R_TYPE(rel->r_info);
754         ElfW(Addr) offset = rel->r_offset;
755         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
756 
757         if (sym->st_shndx == SHN_UNDEF)
758                 return 0;
759 
760         /*
761          * Adjust the offset if this reloc applies to the percpu section.
762          */
763         if (sec->shdr.sh_info == per_cpu_shndx)
764                 offset += per_cpu_load_addr;
765 
766         switch (r_type) {
767         case R_X86_64_NONE:
768                 /* NONE can be ignored. */
769                 break;
770 
771         case R_X86_64_PC32:
772                 /*
773                  * PC relative relocations don't need to be adjusted unless
774                  * referencing a percpu symbol.
775                  */
776                 if (is_percpu_sym(sym, symname))
777                         add_reloc(&relocs32neg, offset);
778                 break;
779 
780         case R_X86_64_32:
781         case R_X86_64_32S:
782         case R_X86_64_64:
783                 /*
784                  * References to the percpu area don't need to be adjusted.
785                  */
786                 if (is_percpu_sym(sym, symname))
787                         break;
788 
789                 if (shn_abs) {
790                         /*
791                          * Whitelisted absolute symbols do not require
792                          * relocation.
793                          */
794                         if (is_reloc(S_ABS, symname))
795                                 break;
796 
797                         die("Invalid absolute %s relocation: %s\n",
798                             rel_type(r_type), symname);
799                         break;
800                 }
801 
802                 /*
803                  * Relocation offsets for 64 bit kernels are output
804                  * as 32 bits and sign extended back to 64 bits when
805                  * the relocations are processed.
806                  * Make sure that the offset will fit.
807                  */
808                 if ((int32_t)offset != (int64_t)offset)
809                         die("Relocation offset doesn't fit in 32 bits\n");
810 
811                 if (r_type == R_X86_64_64)
812                         add_reloc(&relocs64, offset);
813                 else
814                         add_reloc(&relocs32, offset);
815                 break;
816 
817         default:
818                 die("Unsupported relocation type: %s (%d)\n",
819                     rel_type(r_type), r_type);
820                 break;
821         }
822 
823         return 0;
824 }
825 
826 #else
827 
828 static int do_reloc32(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
829                       const char *symname)
830 {
831         unsigned r_type = ELF32_R_TYPE(rel->r_info);
832         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
833 
834         switch (r_type) {
835         case R_386_NONE:
836         case R_386_PC32:
837         case R_386_PC16:
838         case R_386_PC8:
839                 /*
840                  * NONE can be ignored and PC relative relocations don't
841                  * need to be adjusted.
842                  */
843                 break;
844 
845         case R_386_32:
846                 if (shn_abs) {
847                         /*
848                          * Whitelisted absolute symbols do not require
849                          * relocation.
850                          */
851                         if (is_reloc(S_ABS, symname))
852                                 break;
853 
854                         die("Invalid absolute %s relocation: %s\n",
855                             rel_type(r_type), symname);
856                         break;
857                 }
858 
859                 add_reloc(&relocs32, rel->r_offset);
860                 break;
861 
862         default:
863                 die("Unsupported relocation type: %s (%d)\n",
864                     rel_type(r_type), r_type);
865                 break;
866         }
867 
868         return 0;
869 }
870 
871 static int do_reloc_real(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
872                          const char *symname)
873 {
874         unsigned r_type = ELF32_R_TYPE(rel->r_info);
875         int shn_abs = (sym->st_shndx == SHN_ABS) && !is_reloc(S_REL, symname);
876 
877         switch (r_type) {
878         case R_386_NONE:
879         case R_386_PC32:
880         case R_386_PC16:
881         case R_386_PC8:
882                 /*
883                  * NONE can be ignored and PC relative relocations don't
884                  * need to be adjusted.
885                  */
886                 break;
887 
888         case R_386_16:
889                 if (shn_abs) {
890                         /*
891                          * Whitelisted absolute symbols do not require
892                          * relocation.
893                          */
894                         if (is_reloc(S_ABS, symname))
895                                 break;
896 
897                         if (is_reloc(S_SEG, symname)) {
898                                 add_reloc(&relocs16, rel->r_offset);
899                                 break;
900                         }
901                 } else {
902                         if (!is_reloc(S_LIN, symname))
903                                 break;
904                 }
905                 die("Invalid %s %s relocation: %s\n",
906                     shn_abs ? "absolute" : "relative",
907                     rel_type(r_type), symname);
908                 break;
909 
910         case R_386_32:
911                 if (shn_abs) {
912                         /*
913                          * Whitelisted absolute symbols do not require
914                          * relocation.
915                          */
916                         if (is_reloc(S_ABS, symname))
917                                 break;
918 
919                         if (is_reloc(S_REL, symname)) {
920                                 add_reloc(&relocs32, rel->r_offset);
921                                 break;
922                         }
923                 } else {
924                         if (is_reloc(S_LIN, symname))
925                                 add_reloc(&relocs32, rel->r_offset);
926                         break;
927                 }
928                 die("Invalid %s %s relocation: %s\n",
929                     shn_abs ? "absolute" : "relative",
930                     rel_type(r_type), symname);
931                 break;
932 
933         default:
934                 die("Unsupported relocation type: %s (%d)\n",
935                     rel_type(r_type), r_type);
936                 break;
937         }
938 
939         return 0;
940 }
941 
942 #endif
943 
944 static int cmp_relocs(const void *va, const void *vb)
945 {
946         const uint32_t *a, *b;
947         a = va; b = vb;
948         return (*a == *b)? 0 : (*a > *b)? 1 : -1;
949 }
950 
951 static void sort_relocs(struct relocs *r)
952 {
953         qsort(r->offset, r->count, sizeof(r->offset[0]), cmp_relocs);
954 }
955 
956 static int write32(uint32_t v, FILE *f)
957 {
958         unsigned char buf[4];
959 
960         put_unaligned_le32(v, buf);
961         return fwrite(buf, 1, 4, f) == 4 ? 0 : -1;
962 }
963 
964 static int write32_as_text(uint32_t v, FILE *f)
965 {
966         return fprintf(f, "\t.long 0x%08"PRIx32"\n", v) > 0 ? 0 : -1;
967 }
968 
969 static void emit_relocs(int as_text, int use_real_mode)
970 {
971         int i;
972         int (*write_reloc)(uint32_t, FILE *) = write32;
973         int (*do_reloc)(struct section *sec, Elf_Rel *rel, Elf_Sym *sym,
974                         const char *symname);
975 
976 #if ELF_BITS == 64
977         if (!use_real_mode)
978                 do_reloc = do_reloc64;
979         else
980                 die("--realmode not valid for a 64-bit ELF file");
981 #else
982         if (!use_real_mode)
983                 do_reloc = do_reloc32;
984         else
985                 do_reloc = do_reloc_real;
986 #endif
987 
988         /* Collect up the relocations */
989         walk_relocs(do_reloc);
990 
991         if (relocs16.count && !use_real_mode)
992                 die("Segment relocations found but --realmode not specified\n");
993 
994         /* Order the relocations for more efficient processing */
995         sort_relocs(&relocs32);
996 #if ELF_BITS == 64
997         sort_relocs(&relocs32neg);
998         sort_relocs(&relocs64);
999 #else
1000         sort_relocs(&relocs16);
1001 #endif
1002 
1003         /* Print the relocations */
1004         if (as_text) {
1005                 /* Print the relocations in a form suitable that
1006                  * gas will like.
1007                  */
1008                 printf(".section \".data.reloc\",\"a\"\n");
1009                 printf(".balign 4\n");
1010                 write_reloc = write32_as_text;
1011         }
1012 
1013         if (use_real_mode) {
1014                 write_reloc(relocs16.count, stdout);
1015                 for (i = 0; i < relocs16.count; i++)
1016                         write_reloc(relocs16.offset[i], stdout);
1017 
1018                 write_reloc(relocs32.count, stdout);
1019                 for (i = 0; i < relocs32.count; i++)
1020                         write_reloc(relocs32.offset[i], stdout);
1021         } else {
1022 #if ELF_BITS == 64
1023                 /* Print a stop */
1024                 write_reloc(0, stdout);
1025 
1026                 /* Now print each relocation */
1027                 for (i = 0; i < relocs64.count; i++)
1028                         write_reloc(relocs64.offset[i], stdout);
1029 
1030                 /* Print a stop */
1031                 write_reloc(0, stdout);
1032 
1033                 /* Now print each inverse 32-bit relocation */
1034                 for (i = 0; i < relocs32neg.count; i++)
1035                         write_reloc(relocs32neg.offset[i], stdout);
1036 #endif
1037 
1038                 /* Print a stop */
1039                 write_reloc(0, stdout);
1040 
1041                 /* Now print each relocation */
1042                 for (i = 0; i < relocs32.count; i++)
1043                         write_reloc(relocs32.offset[i], stdout);
1044         }
1045 }
1046 
1047 /*
1048  * As an aid to debugging problems with different linkers
1049  * print summary information about the relocs.
1050  * Since different linkers tend to emit the sections in
1051  * different orders we use the section names in the output.
1052  */
1053 static int do_reloc_info(struct section *sec, Elf_Rel *rel, ElfW(Sym) *sym,
1054                                 const char *symname)
1055 {
1056         printf("%s\t%s\t%s\t%s\n",
1057                 sec_name(sec->shdr.sh_info),
1058                 rel_type(ELF_R_TYPE(rel->r_info)),
1059                 symname,
1060                 sec_name(sym->st_shndx));
1061         return 0;
1062 }
1063 
1064 static void print_reloc_info(void)
1065 {
1066         printf("reloc section\treloc type\tsymbol\tsymbol section\n");
1067         walk_relocs(do_reloc_info);
1068 }
1069 
1070 #if ELF_BITS == 64
1071 # define process process_64
1072 #else
1073 # define process process_32
1074 #endif
1075 
1076 void process(FILE *fp, int use_real_mode, int as_text,
1077              int show_absolute_syms, int show_absolute_relocs,
1078              int show_reloc_info)
1079 {
1080         regex_init(use_real_mode);
1081         read_ehdr(fp);
1082         read_shdrs(fp);
1083         read_strtabs(fp);
1084         read_symtabs(fp);
1085         read_relocs(fp);
1086         if (ELF_BITS == 64)
1087                 percpu_init();
1088         if (show_absolute_syms) {
1089                 print_absolute_symbols();
1090                 return;
1091         }
1092         if (show_absolute_relocs) {
1093                 print_absolute_relocs();
1094                 return;
1095         }
1096         if (show_reloc_info) {
1097                 print_reloc_info();
1098                 return;
1099         }
1100         emit_relocs(as_text, use_real_mode);
1101 }
1102 

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