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04637865 | 1 | /* Machine-dependent ELF dynamic relocation inline functions. ARM version. |
44bff568 | 2 | Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc. |
04637865 UD |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Library General Public License as | |
7 | published by the Free Software Foundation; either version 2 of the | |
8 | License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Library General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Library General Public | |
16 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
17 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
18 | Boston, MA 02111-1307, USA. */ | |
19 | ||
20 | #ifndef dl_machine_h | |
21 | #define dl_machine_h | |
22 | ||
23 | #define ELF_MACHINE_NAME "ARM" | |
24 | ||
25 | #include <sys/param.h> | |
26 | ||
26de9a82 UD |
27 | #define VALID_ELF_ABIVERSION(ver) (ver == 0) |
28 | #define VALID_ELF_OSABI(osabi) \ | |
29 | (osabi == ELFOSABI_SYSV || osabi == ELFOSABI_ARM) | |
30 | #define VALID_ELF_HEADER(hdr,exp,size) \ | |
31 | memcmp (hdr,exp,size-2) == 0 \ | |
32 | && VALID_ELF_OSABI (hdr[EI_OSABI]) \ | |
33 | && VALID_ELF_ABIVERSION (hdr[EI_ABIVERSION]) | |
34 | ||
9d1306dd UD |
35 | #define CLEAR_CACHE(BEG,END) \ |
36 | { \ | |
37 | register unsigned long _beg __asm ("a1") = (unsigned long)(BEG); \ | |
2dfdce51 | 38 | register unsigned long _end __asm ("a2") = (unsigned long)(END); \ |
9d1306dd | 39 | register unsigned long _flg __asm ("a3") = 0; \ |
9b1eef96 UD |
40 | __asm __volatile ("swi 0x9f0002 @ sys_cacheflush" \ |
41 | : /* no outputs */ \ | |
42 | : /* no inputs */ \ | |
43 | : "a1"); \ | |
9d1306dd UD |
44 | } |
45 | ||
04637865 UD |
46 | /* Return nonzero iff E_MACHINE is compatible with the running host. */ |
47 | static inline int __attribute__ ((unused)) | |
48 | elf_machine_matches_host (Elf32_Half e_machine) | |
49 | { | |
50 | switch (e_machine) | |
51 | { | |
52 | case EM_ARM: | |
53 | return 1; | |
54 | default: | |
55 | return 0; | |
56 | } | |
57 | } | |
58 | ||
59 | ||
60 | /* Return the link-time address of _DYNAMIC. Conveniently, this is the | |
61 | first element of the GOT. This must be inlined in a function which | |
62 | uses global data. */ | |
63 | static inline Elf32_Addr __attribute__ ((unused)) | |
64 | elf_machine_dynamic (void) | |
65 | { | |
66 | register Elf32_Addr *got asm ("r10"); | |
67 | return *got; | |
68 | } | |
69 | ||
70 | ||
71 | /* Return the run-time load address of the shared object. */ | |
04637865 UD |
72 | static inline Elf32_Addr __attribute__ ((unused)) |
73 | elf_machine_load_address (void) | |
74 | { | |
e79468a2 UD |
75 | extern void __dl_start asm ("_dl_start"); |
76 | Elf32_Addr got_addr = (Elf32_Addr) &__dl_start; | |
77 | Elf32_Addr pcrel_addr; | |
78 | asm ("adr %0, _dl_start" : "=r" (pcrel_addr)); | |
79 | return pcrel_addr - got_addr; | |
04637865 UD |
80 | } |
81 | ||
82 | ||
83 | /* Set up the loaded object described by L so its unrelocated PLT | |
84 | entries will jump to the on-demand fixup code in dl-runtime.c. */ | |
85 | ||
86 | static inline int __attribute__ ((unused)) | |
87 | elf_machine_runtime_setup (struct link_map *l, int lazy, int profile) | |
88 | { | |
89 | Elf32_Addr *got; | |
90 | extern void _dl_runtime_resolve (Elf32_Word); | |
91 | extern void _dl_runtime_profile (Elf32_Word); | |
92 | ||
93 | if (l->l_info[DT_JMPREL] && lazy) | |
94 | { | |
95 | /* patb: this is different than i386 */ | |
96 | /* The GOT entries for functions in the PLT have not yet been filled | |
97 | in. Their initial contents will arrange when called to push an | |
98 | index into the .got section, load ip with &_GLOBAL_OFFSET_TABLE_[3], | |
99 | and then jump to _GLOBAL_OFFSET_TABLE[2]. */ | |
a96af7b9 | 100 | got = (Elf32_Addr *) l->l_info[DT_PLTGOT]->d_un.d_ptr; |
04637865 UD |
101 | got[1] = (Elf32_Addr) l; /* Identify this shared object. */ |
102 | ||
103 | /* The got[2] entry contains the address of a function which gets | |
104 | called to get the address of a so far unresolved function and | |
105 | jump to it. The profiling extension of the dynamic linker allows | |
106 | to intercept the calls to collect information. In this case we | |
107 | don't store the address in the GOT so that all future calls also | |
108 | end in this function. */ | |
109 | if (profile) | |
110 | { | |
344b4b4e | 111 | got[2] = (Elf32_Addr) &_dl_runtime_profile; |
04637865 UD |
112 | /* Say that we really want profiling and the timers are started. */ |
113 | _dl_profile_map = l; | |
114 | } | |
115 | else | |
116 | /* This function will get called to fix up the GOT entry indicated by | |
117 | the offset on the stack, and then jump to the resolved address. */ | |
118 | got[2] = (Elf32_Addr) &_dl_runtime_resolve; | |
119 | } | |
120 | return lazy; | |
121 | } | |
122 | ||
123 | /* This code is used in dl-runtime.c to call the `fixup' function | |
124 | and then redirect to the address it returns. */ | |
125 | // macro for handling PIC situation.... | |
126 | #ifdef PIC | |
127 | #define CALL_ROUTINE(x) " ldr sl,0f | |
128 | add sl, pc, sl | |
129 | 1: ldr r2, 2f | |
130 | mov lr, pc | |
131 | add pc, sl, r2 | |
132 | b 3f | |
133 | 0: .word _GLOBAL_OFFSET_TABLE_ - 1b - 4 | |
134 | 2: .word " #x "(GOTOFF) | |
135 | 3: " | |
136 | #else | |
137 | #define CALL_ROUTINE(x) " bl " #x | |
138 | #endif | |
139 | ||
140 | #ifndef PROF | |
141 | # define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ | |
142 | .text | |
143 | .globl _dl_runtime_resolve | |
144 | .type _dl_runtime_resolve, #function | |
145 | .align 2 | |
146 | _dl_runtime_resolve: | |
147 | @ we get called with | |
148 | @ stack[0] contains the return address from this call | |
149 | @ ip contains &GOT[n+3] (pointer to function) | |
150 | @ lr points to &GOT[2] | |
151 | ||
152 | @ save almost everything; lr is already on the stack | |
153 | stmdb sp!,{r0-r3,sl,fp} | |
154 | ||
155 | @ prepare to call fixup() | |
04637865 UD |
156 | @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each |
157 | sub r1, ip, lr | |
158 | sub r1, r1, #4 | |
159 | add r1, r1, r1 | |
160 | ||
161 | @ get pointer to linker struct | |
162 | ldr r0, [lr, #-4] | |
163 | ||
333014b8 | 164 | @ call fixup routine |
04637865 UD |
165 | " CALL_ROUTINE(fixup) " |
166 | ||
167 | @ save the return | |
168 | mov ip, r0 | |
169 | ||
170 | @ restore the stack | |
171 | ldmia sp!,{r0-r3,sl,fp,lr} | |
172 | ||
173 | @ jump to the newly found address | |
174 | mov pc, ip | |
175 | ||
176 | .size _dl_runtime_resolve, .-_dl_runtime_resolve | |
68d11b26 | 177 | |
04637865 UD |
178 | .globl _dl_runtime_profile |
179 | .type _dl_runtime_profile, #function | |
180 | .align 2 | |
181 | _dl_runtime_profile: | |
333014b8 UD |
182 | @ save almost everything; lr is already on the stack |
183 | stmdb sp!,{r0-r3,sl,fp} | |
04637865 UD |
184 | |
185 | @ prepare to call fixup() | |
04637865 UD |
186 | @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each |
187 | sub r1, ip, lr | |
188 | sub r1, r1, #4 | |
189 | add r1, r1, r1 | |
190 | ||
191 | @ get pointer to linker struct | |
192 | ldr r0, [lr, #-4] | |
193 | ||
333014b8 | 194 | @ call profiling fixup routine |
04637865 UD |
195 | " CALL_ROUTINE(profile_fixup) " |
196 | ||
197 | @ save the return | |
198 | mov ip, r0 | |
199 | ||
200 | @ restore the stack | |
333014b8 | 201 | ldmia sp!,{r0-r3,sl,fp,lr} |
04637865 UD |
202 | |
203 | @ jump to the newly found address | |
204 | mov pc, ip | |
205 | ||
333014b8 | 206 | .size _dl_runtime_resolve, .-_dl_runtime_resolve |
04637865 UD |
207 | .previous |
208 | "); | |
209 | #else // PROF | |
210 | # define ELF_MACHINE_RUNTIME_TRAMPOLINE asm ("\ | |
211 | .text | |
212 | .globl _dl_runtime_resolve | |
213 | .globl _dl_runtime_profile | |
214 | .type _dl_runtime_resolve, #function | |
215 | .type _dl_runtime_profile, #function | |
216 | .align 2 | |
217 | _dl_runtime_resolve: | |
218 | _dl_runtime_profile: | |
333014b8 UD |
219 | @ we get called with |
220 | @ stack[0] contains the return address from this call | |
221 | @ ip contains &GOT[n+3] (pointer to function) | |
222 | @ lr points to &GOT[2] | |
223 | ||
224 | @ save almost everything; return add is already on the stack | |
225 | stmdb sp!,{r0-r3,sl,fp} | |
226 | ||
227 | @ prepare to call fixup() | |
228 | @ change &GOT[n+3] into 8*n NOTE: reloc are 8 bytes each | |
04637865 UD |
229 | sub r1, ip, lr |
230 | sub r1, r1, #4 | |
231 | add r1, r1, r1 | |
333014b8 UD |
232 | |
233 | @ get pointer to linker struct | |
04637865 | 234 | ldr r0, [lr, #-4] |
333014b8 UD |
235 | |
236 | @ call profiling fixup routine | |
04637865 | 237 | " CALL_ROUTINE(fixup) " |
333014b8 UD |
238 | |
239 | @ save the return | |
04637865 | 240 | mov ip, r0 |
333014b8 UD |
241 | |
242 | @ restore the stack | |
243 | ldmia sp!,{r0-r3,sl,fp,lr} | |
244 | ||
245 | @ jump to the newly found address | |
04637865 UD |
246 | mov pc, ip |
247 | ||
248 | .size _dl_runtime_profile, .-_dl_runtime_profile | |
249 | .previous | |
250 | "); | |
251 | #endif //PROF | |
252 | ||
253 | /* Mask identifying addresses reserved for the user program, | |
254 | where the dynamic linker should not map anything. */ | |
255 | #define ELF_MACHINE_USER_ADDRESS_MASK 0xf8000000UL | |
256 | ||
257 | /* Initial entry point code for the dynamic linker. | |
258 | The C function `_dl_start' is the real entry point; | |
259 | its return value is the user program's entry point. */ | |
260 | ||
261 | #define RTLD_START asm ("\ | |
262 | .text | |
263 | .globl _start | |
264 | .globl _dl_start_user | |
265 | _start: | |
266 | @ at start time, all the args are on the stack | |
267 | mov r0, sp | |
268 | bl _dl_start | |
269 | @ returns user entry point in r0 | |
270 | _dl_start_user: | |
271 | mov r6, r0 | |
272 | @ we are PIC code, so get global offset table | |
273 | ldr sl, .L_GET_GOT | |
274 | add sl, pc, sl | |
275 | .L_GOT_GOT: | |
333014b8 UD |
276 | @ Store the highest stack address |
277 | ldr r1, .L_STACK_END | |
278 | ldr r1, [sl, r1] | |
279 | str sp, [r1] | |
04637865 UD |
280 | @ See if we were run as a command with the executable file |
281 | @ name as an extra leading argument. | |
282 | ldr r1, .L_SKIP_ARGS | |
283 | ldr r1, [sl, r1] | |
284 | @ get the original arg count | |
285 | ldr r0, [sp] | |
286 | @ subtract _dl_skip_args from it | |
287 | sub r0, r0, r1 | |
288 | @ adjust the stack pointer to skip them | |
289 | add sp, sp, r1, lsl #2 | |
290 | @ store the new argc in the new stack location | |
291 | str r0, [sp] | |
292 | ||
293 | @ now we enter a _dl_init_next loop | |
344b4b4e UD |
294 | ldr r4, .L_MAIN_SEARCHLIST |
295 | ldr r4, [sl, r4] | |
c0e2368b | 296 | ldr r4, [r4] |
04637865 UD |
297 | @ call _dl_init_next to get the address of an initalizer |
298 | 0: mov r0, r4 | |
299 | bl _dl_init_next(PLT) | |
300 | cmp r0, #0 | |
301 | beq 1f | |
302 | @ call the shared-object initializer | |
303 | @ during this call, the stack may get moved around | |
304 | mov lr, pc | |
305 | mov pc, r0 | |
306 | @ go back and look for another initializer | |
307 | b 0b | |
308 | 1: @ clear the startup flag | |
309 | ldr r2, .L_STARTUP_FLAG | |
310 | ldr r1, [sl, r2] | |
311 | @ we know r0==0 at this point | |
312 | str r0, [r1] | |
313 | @ load the finalizer function | |
314 | ldr r0, .L_FINI_PROC | |
315 | ldr r0, [sl, r0] | |
316 | @ jump to the user_s entry point | |
317 | mov pc, r6 | |
318 | .L_GET_GOT: | |
319 | .word _GLOBAL_OFFSET_TABLE_ - .L_GOT_GOT - 4 \n\ | |
320 | .L_SKIP_ARGS: \n\ | |
321 | .word _dl_skip_args(GOTOFF) \n\ | |
04637865 UD |
322 | .L_STARTUP_FLAG: |
323 | .word _dl_starting_up(GOT) | |
324 | .L_FINI_PROC: | |
325 | .word _dl_fini(GOT) | |
333014b8 UD |
326 | .L_STACK_END: |
327 | .word __libc_stack_end(GOT) | |
f036f1a9 | 328 | .L_MAIN_SEARCHLIST: |
344b4b4e | 329 | .word _dl_main_searchlist(GOT) |
04637865 UD |
330 | .previous\n\ |
331 | "); | |
332 | ||
333 | /* Nonzero iff TYPE should not be allowed to resolve to one of | |
334 | the main executable's symbols, as for a COPY reloc. */ | |
335 | #define elf_machine_lookup_noexec_p(type) ((type) == R_ARM_COPY) | |
336 | ||
337 | /* Nonzero iff TYPE describes relocation of a PLT entry, so | |
338 | PLT entries should not be allowed to define the value. */ | |
70217455 | 339 | #define elf_machine_lookup_noplt_p(type) ((type) == R_ARM_JUMP_SLOT) |
04637865 UD |
340 | |
341 | /* A reloc type used for ld.so cmdline arg lookups to reject PLT entries. */ | |
70217455 | 342 | #define ELF_MACHINE_JMP_SLOT R_ARM_JUMP_SLOT |
04637865 | 343 | |
56984f46 | 344 | /* The ARM never uses Elf32_Rela relocations. */ |
04637865 UD |
345 | #define ELF_MACHINE_NO_RELA 1 |
346 | ||
347 | /* We define an initialization functions. This is called very early in | |
348 | _dl_sysdep_start. */ | |
349 | #define DL_PLATFORM_INIT dl_platform_init () | |
350 | ||
351 | extern const char *_dl_platform; | |
352 | ||
353 | static inline void __attribute__ ((unused)) | |
354 | dl_platform_init (void) | |
355 | { | |
9b1eef96 UD |
356 | if (_dl_platform != NULL && *_dl_platform == '\0') |
357 | /* Avoid an empty string which would disturb us. */ | |
358 | _dl_platform = NULL; | |
04637865 UD |
359 | } |
360 | ||
361 | static inline void | |
362 | elf_machine_fixup_plt (struct link_map *map, const Elf32_Rel *reloc, | |
363 | Elf32_Addr *reloc_addr, Elf32_Addr value) | |
364 | { | |
365 | *reloc_addr = value; | |
366 | } | |
367 | ||
368 | /* Return the final value of a plt relocation. */ | |
369 | static inline Elf32_Addr | |
370 | elf_machine_plt_value (struct link_map *map, const Elf32_Rel *reloc, | |
371 | Elf32_Addr value) | |
372 | { | |
373 | return value; | |
374 | } | |
375 | ||
376 | #endif /* !dl_machine_h */ | |
377 | ||
378 | #ifdef RESOLVE | |
379 | ||
380 | extern char **_dl_argv; | |
381 | ||
382 | /* Perform the relocation specified by RELOC and SYM (which is fully resolved). | |
383 | MAP is the object containing the reloc. */ | |
384 | ||
385 | static inline void | |
386 | elf_machine_rel (struct link_map *map, const Elf32_Rel *reloc, | |
387 | const Elf32_Sym *sym, const struct r_found_version *version, | |
388 | Elf32_Addr *const reloc_addr) | |
389 | { | |
390 | if (ELF32_R_TYPE (reloc->r_info) == R_ARM_RELATIVE) | |
391 | { | |
392 | #ifndef RTLD_BOOTSTRAP | |
393 | if (map != &_dl_rtld_map) /* Already done in rtld itself. */ | |
394 | #endif | |
395 | *reloc_addr += map->l_addr; | |
396 | } | |
397 | else if (ELF32_R_TYPE (reloc->r_info) != R_ARM_NONE) | |
398 | { | |
399 | const Elf32_Sym *const refsym = sym; | |
400 | Elf32_Addr value = RESOLVE (&sym, version, ELF32_R_TYPE (reloc->r_info)); | |
401 | if (sym) | |
402 | value += sym->st_value; | |
403 | ||
404 | switch (ELF32_R_TYPE (reloc->r_info)) | |
405 | { | |
406 | case R_ARM_COPY: | |
407 | if (sym == NULL) | |
408 | /* This can happen in trace mode if an object could not be | |
409 | found. */ | |
410 | break; | |
411 | if (sym->st_size > refsym->st_size | |
412 | || (_dl_verbose && sym->st_size < refsym->st_size)) | |
413 | { | |
414 | const char *strtab; | |
415 | ||
44bff568 | 416 | strtab = (const void *) map->l_info[DT_STRTAB]->d_un.d_ptr; |
04637865 UD |
417 | _dl_sysdep_error (_dl_argv[0] ?: "<program name unknown>", |
418 | ": Symbol `", strtab + refsym->st_name, | |
419 | "' has different size in shared object, " | |
420 | "consider re-linking\n", NULL); | |
421 | } | |
422 | memcpy (reloc_addr, (void *) value, MIN (sym->st_size, | |
423 | refsym->st_size)); | |
424 | break; | |
425 | case R_ARM_GLOB_DAT: | |
70217455 | 426 | case R_ARM_JUMP_SLOT: |
44bff568 | 427 | #ifdef RTLD_BOOTSTRAP |
e7782e5e | 428 | /* Fix weak undefined references. */ |
44bff568 | 429 | if (sym != NULL && sym->st_value == 0) |
e7782e5e UD |
430 | *reloc_addr = 0; |
431 | else | |
432 | #endif | |
433 | *reloc_addr = value; | |
04637865 | 434 | break; |
70217455 | 435 | case R_ARM_ABS32: |
04637865 UD |
436 | { |
437 | #ifndef RTLD_BOOTSTRAP | |
438 | /* This is defined in rtld.c, but nowhere in the static | |
439 | libc.a; make the reference weak so static programs can | |
440 | still link. This declaration cannot be done when | |
441 | compiling rtld.c (i.e. #ifdef RTLD_BOOTSTRAP) because | |
442 | rtld.c contains the common defn for _dl_rtld_map, which | |
443 | is incompatible with a weak decl in the same file. */ | |
444 | weak_extern (_dl_rtld_map); | |
445 | if (map == &_dl_rtld_map) | |
446 | /* Undo the relocation done here during bootstrapping. | |
447 | Now we will relocate it anew, possibly using a | |
448 | binding found in the user program or a loaded library | |
449 | rather than the dynamic linker's built-in definitions | |
450 | used while loading those libraries. */ | |
451 | value -= map->l_addr + refsym->st_value; | |
452 | #endif | |
453 | *reloc_addr += value; | |
454 | break; | |
455 | } | |
d1af493c UD |
456 | case R_ARM_PC24: |
457 | { | |
458 | signed int addend; | |
459 | ||
460 | addend = *reloc_addr & 0x00ffffff; | |
461 | if (addend & 0x00800000) addend |= 0xff000000; | |
462 | ||
463 | value = value - (unsigned int)reloc_addr + (addend << 2); | |
464 | if (value & 0xfc000003) | |
465 | _dl_signal_error (0, map->l_name, | |
466 | "R_ARM_PC24 relocation out of range"); | |
467 | ||
468 | value = value >> 2; | |
469 | value = (*reloc_addr & 0xff000000) | (value & 0x00ffffff); | |
470 | *reloc_addr = value; | |
471 | } | |
472 | break; | |
04637865 | 473 | default: |
893f3d10 | 474 | _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 0); |
04637865 UD |
475 | break; |
476 | } | |
477 | } | |
478 | } | |
479 | ||
480 | static inline void | |
893f3d10 RM |
481 | elf_machine_lazy_rel (struct link_map *map, |
482 | Elf32_Addr l_addr, const Elf32_Rel *reloc) | |
04637865 | 483 | { |
68d11b26 | 484 | Elf32_Addr *const reloc_addr = (void *) (l_addr + reloc->r_offset); |
344b4b4e | 485 | /* Check for unexpected PLT reloc type. */ |
893f3d10 RM |
486 | if (ELF32_R_TYPE (reloc->r_info) == R_ARM_JUMP_SLOT) |
487 | *reloc_addr += l_addr; | |
488 | else | |
489 | _dl_reloc_bad_type (map, ELF32_R_TYPE (reloc->r_info), 1); | |
04637865 UD |
490 | } |
491 | ||
492 | #endif /* RESOLVE */ |