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rtl-mdreloc-arm.c @ 7219d3c

Last change on this file since 7219d3c was 5500232, checked in by Ryan Long <ryan.long@…>, on 08/08/22 at 14:23:48

libdl: Refactor shared code in ARM and AArch64

rtl-mdreloc-arm.c was used as the basis for rtl-mdreloc-aarch64.c. This lead
to some code being shared by the two files. The code was consolidated into
rtl-unwind-arm.c.

Closes #4686

Property mode set to 100644

File size: 18.2 KB

Line
1	/*
2	* Taken from NetBSD and stripped of the relocations not needed on RTEMS.
3	*/
4
5	/* $NetBSD: mdreloc.c,v 1.33 2010/01/14 12:12:07 skrll Exp $ */
6
7	#include <sys/cdefs.h>
8
9	#include <errno.h>
10	#include <inttypes.h>
11	#include <stdio.h>
12	#include <string.h>
13	#include <sys/types.h>
14	#include <sys/stat.h>
15
16	#include <rtems/rtl/rtl.h>
17	#include "rtl-elf.h"
18	#include "rtl-error.h"
19	#include <rtems/rtl/rtl-trace.h>
20	#include "rtl-unwind-arm.h"
21
22	/*
23	* Set to 1 to allow untested relocations. If you tested one and it
24	* works or you fixed the relocation please remove the guard.
25	*/
26	#define ALLOW_UNTESTED_RELOCS 1
27
28	/*
29	* It is possible for the compiler to emit relocations for unaligned data.
30	* We handle this situation with these inlines.
31	*/
32	#define RELOC_ALIGNED_P(x) \
33	(((uintptr_t)(x) & (sizeof(void *) - 1)) == 0)
34
35	#define SHT_ARM_EXIDX 0x70000001 /* Section holds ARM unwind info. */
36
37	static inline Elf_Addr
38	load_ptr(void *where)
39	{
40	Elf_Addr res;
41
42	memcpy(&res, where, sizeof(res));
43
44	return (res);
45	}
46
47	static inline void
48	store_ptr(void *where, Elf_Addr val)
49	{
50	memcpy(where, &val, sizeof(val));
51	}
52
53	/*
54	* The address of Thumb function symbols is it's real address plus one.
55	* This is done by compiler, thus do not consider symtype here.
56	*/
57	static inline int
58	isThumb(Elf_Word symvalue)
59	{
60	if ((symvalue & 0x1) == 0x1)
61	return true;
62	else return false;
63	}
64
65	static inline Elf_SOff
66	sign_extend31(Elf_Addr val)
67	{
68	if (0x40000000 & val)
69	val = ~((Elf_Addr)0x7fffffff) \| (0x7fffffff & val);
70	return 0x7fffffff & val;
71	}
72
73	static void*
74	set_veneer(void* tramopline, Elf_Addr target)
75	{
76	/*
77	* http://shell-storm.org/online/Online-Assembler-and-Disassembler/
78	*
79	* Thumb mode:
80	* ldr.w pc, [pc]
81	*
82	* ARM mode:
83	* ldr pc, [pc, #-4]
84	*
85	*/
86	uint32_t* tramp = (uint32_t*) tramopline;
87	#if defined(__thumb__)
88	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
89	*tramp++ = 0xf000f8df;
90	#else
91	tramp++ = 0xf8dff000; / not tested */
92	#endif
93	#else
94	#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
95	*tramp++ = 0xe51ff004;
96	#else
97	tramp++ = 0xe51ff004; / not tested */
98	#endif
99	#endif
100	*tramp++ = (uint32_t) target;
101	return tramp;
102	}
103
104	static size_t
105	get_veneer_size(int type)
106	{
107	(void) type;
108	return 8;
109	}
110
111	size_t
112	rtems_rtl_elf_relocate_tramp_max_size (void)
113	{
114	return 8;
115	}
116
117	uint32_t
118	rtems_rtl_elf_section_flags (const rtems_rtl_obj* obj,
119	const Elf_Shdr* shdr)
120	{
121	uint32_t flags = 0;
122	if (shdr->sh_type == SHT_ARM_EXIDX)
123	flags = RTEMS_RTL_OBJ_SECT_EH \| RTEMS_RTL_OBJ_SECT_LOAD;
124	return flags;
125	}
126
127	uint32_t
128	rtems_rtl_elf_arch_parse_section (const rtems_rtl_obj* obj,
129	int section,
130	const char* name,
131	const Elf_Shdr* shdr,
132	const uint32_t flags)
133	{
134	(void) obj;
135	(void) section;
136	(void) name;
137	(void) shdr;
138	return flags;
139	}
140
141	bool
142	rtems_rtl_elf_arch_section_alloc (const rtems_rtl_obj* obj,
143	rtems_rtl_obj_sect* sect)
144	{
145	(void) obj;
146	(void) sect;
147	return false;
148	}
149
150	bool
151	rtems_rtl_elf_arch_section_free (const rtems_rtl_obj* obj,
152	rtems_rtl_obj_sect* sect)
153	{
154	(void) obj;
155	(void) sect;
156	return false;
157	}
158
159	bool
160	rtems_rtl_elf_rel_resolve_sym (Elf_Word type)
161	{
162	return true;
163	}
164
165	rtems_rtl_elf_rel_status
166	rtems_rtl_elf_relocate_rela_tramp (rtems_rtl_obj* obj,
167	const Elf_Rela* rela,
168	const rtems_rtl_obj_sect* sect,
169	const char* symname,
170	const Elf_Byte syminfo,
171	const Elf_Word symvalue)
172	{
173	(void) obj;
174	(void) rela;
175	(void) sect;
176	(void) symname;
177	(void) syminfo;
178	(void) symvalue;
179	rtems_rtl_set_error (EINVAL, "rela type record not supported");
180	return rtems_rtl_elf_rel_failure;
181	}
182
183	rtems_rtl_elf_rel_status
184	rtems_rtl_elf_relocate_rela (rtems_rtl_obj* obj,
185	const Elf_Rela* rela,
186	const rtems_rtl_obj_sect* sect,
187	const char* symname,
188	const Elf_Byte syminfo,
189	const Elf_Word symvalue)
190	{
191	(void) obj;
192	(void) rela;
193	(void) sect;
194	(void) symname;
195	(void) syminfo;
196	(void) symvalue;
197	rtems_rtl_set_error (EINVAL, "rela type record not supported");
198	return rtems_rtl_elf_rel_failure;
199	}
200
201	static rtems_rtl_elf_rel_status
202	rtems_rtl_elf_reloc_rel (rtems_rtl_obj* obj,
203	const Elf_Rel* rel,
204	const rtems_rtl_obj_sect* sect,
205	const char* symname,
206	const Elf_Byte syminfo,
207	const Elf_Word symvalue,
208	const bool parsing)
209	{
210	Elf_Addr *where;
211	Elf_Addr tmp;
212	Elf_Word insn, addend;
213	Elf_Word sign, i1, i2;
214	uint16_t lower_insn, upper_insn;
215
216	where = (Elf_Addr *)(sect->base + rel->r_offset);
217
218	switch (ELF_R_TYPE(rel->r_info)) {
219	case R_TYPE(NONE):
220	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) {
221	printf ("rtl: NONE %p in %s\n", where, rtems_rtl_obj_oname (obj));
222	}
223	break;
224
225	case R_TYPE(CALL): /* BL/BLX */
226	case R_TYPE(JUMP24): /* B/BL<cond> */
227	if (parsing)
228	{
229	addend = 0;
230	}
231	else
232	{
233	insn = *where;
234
235	if (insn & 0x00800000)
236	addend = insn \| 0xff000000;
237	else addend = insn & 0x00ffffff;
238
239	if (isThumb(symvalue)) {
240	if ((insn & 0xfe000000) == 0xfa000000); /* Already blx */
241	else {
242	if ((insn & 0xff000000) == 0xeb000000) { /* BL <label> */
243	where = (insn & 0x00ffffff) \| 0xfa000000; / BL-->BLX */
244	} else {
245	printf("JUMP24 is not suppored from arm to thumb\n");
246	return rtems_rtl_elf_rel_failure;
247	}
248	}
249	}
250	}
251
252	if (parsing && sect->base == 0) {
253	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
254	printf ("rtl: JUMP24/PC24/CALL tramp cache\n");
255	return rtems_rtl_elf_rel_tramp_cache;
256	}
257
258	tmp = symvalue + (addend << 2) - (Elf_Addr)where;
259	tmp = (Elf_Sword)tmp >> 2;
260
261	if (((Elf_Sword)tmp > 0x7fffff) \|\| ((Elf_Sword)tmp < -0x800000)) {
262	Elf_Word tramp_addr;
263	size_t tramp_size = get_veneer_size(ELF_R_TYPE(rel->r_info));
264
265	if (parsing) {
266	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
267	printf ("rtl: JUMP24/PC24/CALL tramp add\n");
268	return rtems_rtl_elf_rel_tramp_add;
269	}
270
271	if (!rtems_rtl_obj_has_tramp_space (obj, tramp_size)) {
272	rtems_rtl_set_error (EINVAL,
273	"%s: CALL/JUMP24: overflow: no tramp memory",
274	sect->name);
275	return rtems_rtl_elf_rel_failure;
276	}
277
278	tramp_addr = ((Elf_Addr) obj->tramp_brk) \| (symvalue & 1);
279	obj->tramp_brk = set_veneer(obj->tramp_brk, symvalue);
280
281	tmp = tramp_addr + (addend << 2) - (Elf_Addr)where;
282	tmp = (Elf_Sword)tmp >> 2;
283	}
284
285	if (!parsing) {
286	where = (where & 0xff000000) \| (tmp & 0xffffff);
287
288	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
289	printf ("rtl: JUMP24/PC24/CALL %p @ %p in %s\n",
290	(void )where, where, rtems_rtl_obj_oname (obj));
291	}
292	break;
293
294	case R_TYPE(V4BX):
295	/* Miscellaneous, ignore */
296	if (!parsing && rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) {
297	printf ("rtl: V4BX @ %p in %s\n",
298	where, rtems_rtl_obj_oname (obj));
299	}
300	break;
301
302	case R_TYPE(MOVT_ABS):
303	case R_TYPE(MOVW_ABS_NC):
304	if (!parsing) {
305	insn = *where;
306
307	addend = ((insn >> 4) & 0xf000) \| (insn & 0x0fff);
308	if (addend & 0x8000)
309	addend \|= 0xffff0000;
310
311	tmp = symvalue + addend;
312
313	if (ELF_R_TYPE(rel->r_info) == R_TYPE(MOVW_ABS_NC))
314	tmp &= 0xffff;
315	else {
316	tmp = (Elf_Sword)tmp >> 16;
317	if (((Elf_Sword)tmp > 0x7fff) \|\| ((Elf_Sword)tmp < -0x8000)) {
318	printf("MOVT_ABS Overflow\n");
319	return rtems_rtl_elf_rel_failure;
320	}
321	}
322
323	*where = (insn & 0xfff0f000) \| ((tmp & 0xf000) << 4) \| (tmp & 0xfff);
324
325	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
326	printf ("rtl: MOVT_ABS/MOVW_ABS_NC %p @ %p in %s\n",
327	(void )where, where, rtems_rtl_obj_oname (obj));
328	}
329	break;
330
331	case R_TYPE(REL32): /* word32 (S + A) \| T - P */
332	case R_TYPE(ABS32): /* word32 (S + A) \| T */
333	case R_TYPE(GLOB_DAT): /* word32 (S + A) \| T */
334	case R_TYPE(PREL31): /* word32 (S + A) \| T - P */
335	case R_TYPE(TARGET1): /* Equivalent to ABS32 */
336	case R_TYPE(TARGET2): /* Equivalent to REL32 */
337	if (!parsing) {
338	if (__predict_true(RELOC_ALIGNED_P(where))) {
339	tmp = *where + symvalue;
340	if (isThumb(symvalue))
341	tmp \|= 1;
342	if (ELF_R_TYPE(rel->r_info) == R_TYPE(REL32) \|\|
343	ELF_R_TYPE(rel->r_info) == R_TYPE(TARGET2))
344	tmp -= (Elf_Addr)where;
345	else if (ELF_R_TYPE(rel->r_info) == R_TYPE(PREL31))
346	tmp = sign_extend31(tmp - (Elf_Addr)where);
347	if (!parsing) {
348	*where = tmp;
349	}
350	} else {
351	tmp = load_ptr(where) + symvalue;
352	if (isThumb(symvalue))
353	tmp \|= 1;
354	if (ELF_R_TYPE(rel->r_info) == R_TYPE(REL32) \|\|
355	ELF_R_TYPE(rel->r_info) == R_TYPE(TARGET2))
356	tmp -= (Elf_Addr)where;
357	else if (ELF_R_TYPE(rel->r_info) == R_TYPE(PREL31))
358	tmp = sign_extend31(tmp - (Elf_Addr)where);
359	store_ptr(where, tmp);
360	}
361
362	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
363	printf ("rtl: REL32/ABS32/GLOB_DAT/PREL31/TARGET2 %p @ %p in %s\n",
364	(void *)tmp, where, rtems_rtl_obj_oname (obj));
365	}
366	break;
367
368	case R_TYPE(THM_MOVT_ABS):
369	case R_TYPE(THM_MOVW_ABS_NC):
370	if (!parsing) {
371	upper_insn = (uint16_t )where;
372	lower_insn = ((uint16_t )where + 1);
373
374	addend = ((upper_insn & 0x000f) << 12) \| ((upper_insn & 0x0400) << 1) \|
375	((lower_insn & 0x7000) >> 4) \| (lower_insn & 0x00ff);
376	addend = (addend ^ 0x8000) - 0x8000;
377
378	tmp = addend + symvalue;
379	if (ELF32_R_TYPE(rel->r_info) == R_ARM_THM_MOVT_ABS)
380	tmp >>= 16;
381
382	(uint16_t )where = (uint16_t)((upper_insn & 0xfbf0) \|
383	((tmp & 0xf000) >> 12) \|
384	((tmp & 0x0800) >> 1));
385	((uint16_t )where + 1) = (uint16_t)((lower_insn & 0x8f00) \|
386	((tmp & 0x0700) << 4) \|
387	(tmp & 0x00ff));
388
389	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)) {
390	printf ("rtl: THM_MOVT_ABS/THM_MOVW_ABS_NC %p @ %p in %s\n",
391	(void )where, where, rtems_rtl_obj_oname (obj));
392	}
393	}
394	break;
395
396	case R_TYPE(THM_JUMP24):
397	/* same as THM_PC22; insn b.w */
398	case R_TYPE(THM_PC22):
399	if (parsing)
400	{
401	addend = 0;
402	upper_insn = 0;
403	lower_insn = 0;
404	}
405	else
406	{
407	upper_insn = (uint16_t )where;
408	lower_insn = ((uint16_t )where + 1);
409	sign = (upper_insn & (1 << 10)) >> 10;
410	i1 = ((lower_insn >> 13) & 1) ^ sign ? 0 : 1;
411	i2 = ((lower_insn >> 11) & 1) ^ sign ? 0 : 1;
412	tmp = (i1 << 23) \| (i2 << 22) \| ((upper_insn & 0x3ff) << 12) \| ((lower_insn & 0x7ff) << 1);
413	addend = (tmp \| ((sign ? 0 : 1) << 24)) - (1 << 24);
414	}
415
416	if (isThumb(symvalue)) ;/Thumb to Thumb call, nothing to care /
417	else {
418	if (ELF_R_TYPE(rel->r_info) == R_TYPE(THM_JUMP24)) {
419	tmp = (tmp + 2) & ~3; /* aligned to 4 bytes only for JUMP24 */
420	#if !ALLOW_UNTESTED_RELOCS
421	printf("THM_JUMP24 to arm not supported\n");
422	return rtems_rtl_elf_rel_failure;
423	#endif
424	}
425	else {
426	/* THM_CALL bl-->blx */
427	lower_insn &= ~(1<<12);
428	}
429	}
430
431	if (parsing && sect->base == 0) {
432	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
433	printf ("rtl: THM_CALL/JUMP24 tramp cache\n");
434	return rtems_rtl_elf_rel_tramp_cache;
435	}
436
437	tmp = symvalue + addend;
438	tmp = tmp - (Elf_Addr)where;
439
440	if (((Elf_Sword)tmp > 0x7fffff) \|\| ((Elf_Sword)tmp < -0x800000)) {
441	Elf_Word tramp_addr;
442	size_t tramp_size = get_veneer_size(ELF_R_TYPE(rel->r_info));
443
444	if (parsing) {
445	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
446	printf ("rtl: THM_CALL/JUMP24 tramp add: %08x - %p = %i\n",
447	symvalue + addend, where, (Elf_Sword) tmp);
448	return rtems_rtl_elf_rel_tramp_add;
449	}
450
451	if (!rtems_rtl_obj_has_tramp_space (obj, tramp_size)) {
452	rtems_rtl_set_error (EINVAL,
453	"%s: THM_CALL/JUMP24: overflow: no tramp memory",
454	sect->name);
455	return rtems_rtl_elf_rel_failure;
456	}
457
458	tramp_addr = ((Elf_Addr) obj->tramp_brk) \| (symvalue & 1);
459	obj->tramp_brk = set_veneer(obj->tramp_brk, symvalue);
460
461
462	tmp = tramp_addr + addend;
463	tmp = tmp - (Elf_Addr)where;
464	}
465
466	if (!parsing) {
467	sign = (tmp >> 24) & 1;
468	(uint16_t )where = (uint16_t)((upper_insn & 0xf800) \| (sign << 10) \|
469	((tmp >> 12) & 0x3ff));
470
471	((uint16_t )where + 1) = (uint16_t)((lower_insn & 0xd000)\|
472	((sign ^ (~(tmp >> 23) & 1)) << 13) \|
473	((sign ^ (~(tmp >> 22) & 1)) << 11) \|
474	((tmp >> 1) & 0x7ff));
475
476	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC)){
477	printf ("rtl: THM_CALL/JUMP24 %p @ %p in %s\n",
478	(void )where, where, rtems_rtl_obj_oname (obj));
479	}
480	}
481	break;
482
483	case R_TYPE(THM_JUMP19):
484
485	if (!isThumb(symvalue)) {
486	printf("THM_JUMP19 to arm not supported\n");
487	return rtems_rtl_elf_rel_failure;
488	}
489
490	upper_insn = (uint16_t )where;
491	lower_insn = ((uint16_t )where + 1);
492	sign = (upper_insn >> 10) & 0x1;
493
494	if ((((upper_insn & 0x3f) >> 7) & 0x7) == 0x7) {
495	printf("THM_JUMP19 failed\n");
496	return false; /if cond <3:1> == '111', see Related codings in armv7a manual /
497	}
498
499	i1 = (lower_insn >> 13) & 0x1;
500	i2 = (lower_insn >> 11) & 0x1;
501
502	tmp = ((i2 << 19) \| (i1 << 18) \| ((upper_insn & 0x3f) << 12) \| ((lower_insn & 0x7ff) << 1));
503	addend = (tmp \| ((sign ? 0 : 1) << 20)) - (1 << 20);
504	tmp = symvalue + addend;
505
506	tmp = tmp - (Elf_Addr)where;
507
508	if (((Elf_Sword)tmp > 0x7ffffe) \|\| ((Elf_Sword)tmp < -0x800000)) {
509	rtems_rtl_set_error (EINVAL, "%s: Overflow %" PRIu32 " "
510	"THM_JUMP19 relocations",
511	sect->name, (uint32_t) ELF_R_TYPE(rel->r_info));
512	return rtems_rtl_elf_rel_failure;
513	}
514
515	sign = (tmp >> 20) & 0x1;
516	i2 = (tmp >> 19) & 0x1;
517	i1 = (tmp >> 18) & 0x1;
518
519	(uint16_t)where = (upper_insn & 0xfbc0) \| (sign << 10) \| ((tmp >> 12) & 0x3f);
520	((uint16_t)where + 1) = (lower_insn & 0xd000) \| (i1 << 13) \|
521	(i2 << 11) \| ((tmp >> 1) & 0x7ff);
522
523	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
524	printf ("rtl: THM_JUMP19 %p @ %p in %s\n",
525	(void )where, where, rtems_rtl_obj_oname (obj));
526	break;
527
528	case R_TYPE(TLS_LE32):
529	#if ALLOW_UNTESTED_RELOCS
530	if (!parsing) {
531	addend = *where;
532	*where = symvalue + addend;
533	if (rtems_rtl_trace (RTEMS_RTL_TRACE_RELOC))
534	printf ("rtl: TLS_LE32 %p @ %p in %s\n",
535	(void )where, where, rtems_rtl_obj_oname (obj));
536	}
537	break;
538	#endif
539	case R_TYPE(TLS_GD32):
540	case R_TYPE(TLS_LDM32):
541	case R_TYPE(TLS_LDO32):
542	case R_TYPE(TLS_IE32):
543	case R_TYPE(TLS_LDO12):
544	case R_TYPE(TLS_LE12):
545	case R_TYPE(TLS_IE12GP):
546	printf("TSL relocations not supported\n");
547
548	default:
549	printf ("rtl: reloc unknown: sym = %" PRIu32 ", type = %" PRIu32 ", offset = %p",
550	ELF_R_SYM(rel->r_info), (uint32_t) ELF_R_TYPE(rel->r_info),
551	(void *)rel->r_offset);
552	if (!parsing)
553	printf("contents = %p", (void )where);
554	printf("\n");
555	rtems_rtl_set_error (EINVAL,
556	"%s: Unsupported relocation type %" PRIu32 " "
557	"in non-PLT relocations",
558	sect->name, (uint32_t) ELF_R_TYPE(rel->r_info));
559	return rtems_rtl_elf_rel_failure;
560	}
561
562	return rtems_rtl_elf_rel_no_error;
563	}
564
565	rtems_rtl_elf_rel_status
566	rtems_rtl_elf_relocate_rel_tramp (rtems_rtl_obj* obj,
567	const Elf_Rel* rel,
568	const rtems_rtl_obj_sect* sect,
569	const char* symname,
570	const Elf_Byte syminfo,
571	const Elf_Word symvalue)
572	{
573	return rtems_rtl_elf_reloc_rel (obj,
574	rel,
575	sect,
576	symname,
577	syminfo,
578	symvalue,
579	true);
580	}
581
582	rtems_rtl_elf_rel_status
583	rtems_rtl_elf_relocate_rel (rtems_rtl_obj* obj,
584	const Elf_Rel* rel,
585	const rtems_rtl_obj_sect* sect,
586	const char* symname,
587	const Elf_Byte syminfo,
588	const Elf_Word symvalue)
589	{
590	return rtems_rtl_elf_reloc_rel (obj,
591	rel,
592	sect,
593	symname,
594	syminfo,
595	symvalue,
596	false);
597	}

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source: rtems/cpukit/libdl/rtl-mdreloc-arm.c @ 7219d3c

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