1 /* Common target-dependent code for ppc64 GDB, the GNU debugger.
2
3 Copyright (C) 1986-2021 Free Software Foundation, Inc.
4
5 This file is part of GDB.
6
7 This program is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3 of the License, or
10 (at your option) any later version.
11
12 This program is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
16
17 You should have received a copy of the GNU General Public License
18 along with this program. If not, see <http://www.gnu.org/licenses/>. */
19
20 #include "defs.h"
21 #include "frame.h"
22 #include "gdbcore.h"
23 #include "infrun.h"
24 #include "ppc-tdep.h"
25 #include "ppc64-tdep.h"
26 #include "elf-bfd.h"
27
28 /* Macros for matching instructions. Note that, since all the
29 operands are masked off before they're or-ed into the instruction,
30 you can use -1 to make masks. */
31
32 #define insn_d(opcd, rts, ra, d) \
33 ((((unsigned (opcd)) & 0x3f) << 26) \
34 | (((unsigned (rts)) & 0x1f) << 21) \
35 | (((unsigned (ra)) & 0x1f) << 16) \
36 | ((unsigned (d)) & 0xffff))
37
38 #define insn_ds(opcd, rts, ra, d, xo) \
39 ((((unsigned (opcd)) & 0x3f) << 26) \
40 | (((unsigned (rts)) & 0x1f) << 21) \
41 | (((unsigned (ra)) & 0x1f) << 16) \
42 | ((unsigned (d)) & 0xfffc) \
43 | ((unsigned (xo)) & 0x3))
44
45 #define insn_xfx(opcd, rts, spr, xo) \
46 ((((unsigned (opcd)) & 0x3f) << 26) \
47 | (((unsigned (rts)) & 0x1f) << 21) \
48 | (((unsigned (spr)) & 0x1f) << 16) \
49 | (((unsigned (spr)) & 0x3e0) << 6) \
50 | (((unsigned (xo)) & 0x3ff) << 1))
51
52 #define prefix(a, b, R, do) \
53 (((0x1) << 26) \
54 | (((unsigned (a)) & 0x3) << 24) \
55 | (((unsigned (b)) & 0x1) << 23) \
56 | (((unsigned (R)) & 0x1) << 20) \
57 | ((unsigned (do)) & 0x3ffff))
58
59 #define insn_md(opcd, ra, rs, sh, me, rc) \
60 ((((unsigned (opcd)) & 0x3f) << 26) \
61 | (((unsigned (rs)) & 0x1f) << 21) \
62 | (((unsigned (ra)) & 0x1f) << 16) \
63 | (((unsigned (sh)) & 0x3e) << 11) \
64 | (((unsigned (me)) & 0x3f) << 25) \
65 | (((unsigned (sh)) & 0x1) << 1) \
66 | ((unsigned (rc)) & 0x1))
67
68 #define insn_x(opcd, rt, ra, rb, opc2) \
69 ((((unsigned (opcd)) & 0x3f) << 26) \
70 | (((unsigned (rt)) & 0x1f) << 21) \
71 | (((unsigned (ra)) & 0x1f) << 16) \
72 | (((unsigned (rb)) & 0x3e) << 11) \
73 | (((unsigned (opc2)) & 0x3FF) << 1))
74
75 #define insn_xo(opcd, rt, ra, rb, oe, rc, opc2) \
76 ((((unsigned (opcd)) & 0x3f) << 26) \
77 | (((unsigned (rt)) & 0x1f) << 21) \
78 | (((unsigned (ra)) & 0x1f) << 16) \
79 | (((unsigned (rb)) & 0x3e) << 11) \
80 | (((unsigned (oe)) & 0x1) << 10) \
81 | (((unsigned (opc2)) & 0x1FF) << 1) \
82 | (((unsigned (rc)))))
83
84 /* PLT_OFF is the TOC-relative offset of a 64-bit PowerPC PLT entry.
85 Return the function's entry point. */
86
87 static CORE_ADDR
ppc64_plt_entry_point(struct frame_info * frame,CORE_ADDR plt_off)88 ppc64_plt_entry_point (struct frame_info *frame, CORE_ADDR plt_off)
89 {
90 struct gdbarch *gdbarch = get_frame_arch (frame);
91 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
92 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
93 CORE_ADDR tocp;
94
95 if (execution_direction == EXEC_REVERSE)
96 {
97 /* If executing in reverse, r2 will have been stored to the stack. */
98 CORE_ADDR sp = get_frame_register_unsigned (frame,
99 tdep->ppc_gp0_regnum + 1);
100 unsigned int sp_off = tdep->elf_abi == POWERPC_ELF_V1 ? 40 : 24;
101 tocp = read_memory_unsigned_integer (sp + sp_off, 8, byte_order);
102 }
103 else
104 tocp = get_frame_register_unsigned (frame, tdep->ppc_gp0_regnum + 2);
105
106 /* The first word of the PLT entry is the function entry point. */
107 return read_memory_unsigned_integer (tocp + plt_off, 8, byte_order);
108 }
109
110 static CORE_ADDR
ppc64_plt_pcrel_entry_point(struct frame_info * frame,CORE_ADDR plt_off,CORE_ADDR pc)111 ppc64_plt_pcrel_entry_point (struct frame_info *frame, CORE_ADDR plt_off,
112 CORE_ADDR pc)
113 {
114 struct gdbarch *gdbarch = get_frame_arch (frame);
115 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
116
117 /* Execution direction doesn't matter, entry is pc + plt_off either way.
118 The first word of the PLT entry is the function entry point. */
119 return read_memory_unsigned_integer (pc + plt_off, 8, byte_order);
120 }
121
122 /* Patterns for the standard linkage functions. These are built by
123 build_plt_stub in bfd/elf64-ppc.c. */
124
125 /* Old ELFv1 PLT call stub. */
126
127 static const struct ppc_insn_pattern ppc64_standard_linkage1[] =
128 {
129 /* addis r12, r2, <any> */
130 { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
131
132 /* std r2, 40(r1) */
133 { (unsigned) -1, insn_ds (62, 2, 1, 40, 0), 0 },
134
135 /* ld r11, <any>(r12) */
136 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 },
137
138 /* addis r12, r12, 1 <optional> */
139 { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 },
140
141 /* ld r2, <any>(r12) */
142 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 },
143
144 /* addis r12, r12, 1 <optional> */
145 { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 },
146
147 /* mtctr r11 */
148 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 },
149
150 /* ld r11, <any>(r12) <optional> */
151 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 },
152
153 /* bctr */
154 { (unsigned) -1, 0x4e800420, 0 },
155
156 { 0, 0, 0 }
157 };
158
159 /* ELFv1 PLT call stub to access PLT entries more than +/- 32k from r2.
160 Also supports older stub with different placement of std 2,40(1),
161 a stub that omits the std 2,40(1), and both versions of power7
162 thread safety read barriers. Note that there are actually two more
163 instructions following "cmpldi r2, 0", "bnectr+" and "b <glink_i>",
164 but there isn't any need to match them. */
165
166 static const struct ppc_insn_pattern ppc64_standard_linkage2[] =
167 {
168 /* std r2, 40(r1) <optional> */
169 { (unsigned) -1, insn_ds (62, 2, 1, 40, 0), 1 },
170
171 /* addis r12, r2, <any> */
172 { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
173
174 /* std r2, 40(r1) <optional> */
175 { (unsigned) -1, insn_ds (62, 2, 1, 40, 0), 1 },
176
177 /* ld r11, <any>(r12) */
178 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 },
179
180 /* addi r12, r12, <any> <optional> */
181 { insn_d (-1, -1, -1, 0), insn_d (14, 12, 12, 0), 1 },
182
183 /* mtctr r11 */
184 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 },
185
186 /* xor r11, r11, r11 <optional> */
187 { (unsigned) -1, 0x7d6b5a78, 1 },
188
189 /* add r12, r12, r11 <optional> */
190 { (unsigned) -1, 0x7d8c5a14, 1 },
191
192 /* ld r2, <any>(r12) */
193 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 },
194
195 /* ld r11, <any>(r12) <optional> */
196 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 },
197
198 /* bctr <optional> */
199 { (unsigned) -1, 0x4e800420, 1 },
200
201 /* cmpldi r2, 0 <optional> */
202 { (unsigned) -1, 0x28220000, 1 },
203
204 { 0, 0, 0 }
205 };
206
207 /* ELFv1 PLT call stub to access PLT entries within +/- 32k of r2. */
208
209 static const struct ppc_insn_pattern ppc64_standard_linkage3[] =
210 {
211 /* std r2, 40(r1) <optional> */
212 { (unsigned) -1, insn_ds (62, 2, 1, 40, 0), 1 },
213
214 /* ld r11, <any>(r2) */
215 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 0 },
216
217 /* addi r2, r2, <any> <optional> */
218 { insn_d (-1, -1, -1, 0), insn_d (14, 2, 2, 0), 1 },
219
220 /* mtctr r11 */
221 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 },
222
223 /* xor r11, r11, r11 <optional> */
224 { (unsigned) -1, 0x7d6b5a78, 1 },
225
226 /* add r2, r2, r11 <optional> */
227 { (unsigned) -1, 0x7c425a14, 1 },
228
229 /* ld r11, <any>(r2) <optional> */
230 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 1 },
231
232 /* ld r2, <any>(r2) */
233 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 2, 0, 0), 0 },
234
235 /* bctr <optional> */
236 { (unsigned) -1, 0x4e800420, 1 },
237
238 /* cmpldi r2, 0 <optional> */
239 { (unsigned) -1, 0x28220000, 1 },
240
241 { 0, 0, 0 }
242 };
243
244 /* ELFv1 PLT call stub to access PLT entries more than +/- 32k from r2.
245 A more modern variant of ppc64_standard_linkage2 differing in
246 register usage. */
247
248 static const struct ppc_insn_pattern ppc64_standard_linkage4[] =
249 {
250 /* std r2, 40(r1) <optional> */
251 { (unsigned) -1, insn_ds (62, 2, 1, 40, 0), 1 },
252
253 /* addis r11, r2, <any> */
254 { insn_d (-1, -1, -1, 0), insn_d (15, 11, 2, 0), 0 },
255
256 /* ld r12, <any>(r11) */
257 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 11, 0, 0), 0 },
258
259 /* addi r11, r11, <any> <optional> */
260 { insn_d (-1, -1, -1, 0), insn_d (14, 11, 11, 0), 1 },
261
262 /* mtctr r12 */
263 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
264
265 /* xor r2, r12, r12 <optional> */
266 { (unsigned) -1, 0x7d826278, 1 },
267
268 /* add r11, r11, r2 <optional> */
269 { (unsigned) -1, 0x7d6b1214, 1 },
270
271 /* ld r2, <any>(r11) */
272 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 11, 0, 0), 0 },
273
274 /* ld r11, <any>(r11) <optional> */
275 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 11, 0, 0), 1 },
276
277 /* bctr <optional> */
278 { (unsigned) -1, 0x4e800420, 1 },
279
280 /* cmpldi r2, 0 <optional> */
281 { (unsigned) -1, 0x28220000, 1 },
282
283 { 0, 0, 0 }
284 };
285
286 /* ELFv1 PLT call stub to access PLT entries within +/- 32k of r2.
287 A more modern variant of ppc64_standard_linkage3 differing in
288 register usage. */
289
290 static const struct ppc_insn_pattern ppc64_standard_linkage5[] =
291 {
292 /* std r2, 40(r1) <optional> */
293 { (unsigned) -1, insn_ds (62, 2, 1, 40, 0), 1 },
294
295 /* ld r12, <any>(r2) */
296 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 2, 0, 0), 0 },
297
298 /* addi r2, r2, <any> <optional> */
299 { insn_d (-1, -1, -1, 0), insn_d (14, 2, 2, 0), 1 },
300
301 /* mtctr r12 */
302 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
303
304 /* xor r11, r12, r12 <optional> */
305 { (unsigned) -1, 0x7d8b6278, 1 },
306
307 /* add r2, r2, r11 <optional> */
308 { (unsigned) -1, 0x7c425a14, 1 },
309
310 /* ld r11, <any>(r2) <optional> */
311 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 1 },
312
313 /* ld r2, <any>(r2) */
314 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 2, 0, 0), 0 },
315
316 /* bctr <optional> */
317 { (unsigned) -1, 0x4e800420, 1 },
318
319 /* cmpldi r2, 0 <optional> */
320 { (unsigned) -1, 0x28220000, 1 },
321
322 { 0, 0, 0 }
323 };
324
325 /* ELFv2 PLT call stub to access PLT entries more than +/- 32k from r2. */
326
327 static const struct ppc_insn_pattern ppc64_standard_linkage6[] =
328 {
329 /* std r2, 24(r1) <optional> */
330 { (unsigned) -1, insn_ds (62, 2, 1, 24, 0), 1 },
331
332 /* addis r11, r2, <any> */
333 { insn_d (-1, -1, -1, 0), insn_d (15, 11, 2, 0), 0 },
334
335 /* ld r12, <any>(r11) */
336 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 11, 0, 0), 0 },
337
338 /* mtctr r12 */
339 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
340
341 /* bctr */
342 { (unsigned) -1, 0x4e800420, 0 },
343
344 { 0, 0, 0 }
345 };
346
347 /* ELFv2 PLT call stub to access PLT entries within +/- 32k of r2. */
348
349 static const struct ppc_insn_pattern ppc64_standard_linkage7[] =
350 {
351 /* std r2, 24(r1) <optional> */
352 { (unsigned) -1, insn_ds (62, 2, 1, 24, 0), 1 },
353
354 /* ld r12, <any>(r2) */
355 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 2, 0, 0), 0 },
356
357 /* mtctr r12 */
358 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
359
360 /* bctr */
361 { (unsigned) -1, 0x4e800420, 0 },
362
363 { 0, 0, 0 }
364 };
365
366 /* ELFv2 PLT call stub to access PLT entries more than +/- 32k from r2,
367 supporting fusion. */
368
369 static const struct ppc_insn_pattern ppc64_standard_linkage8[] =
370 {
371 /* std r2, 24(r1) <optional> */
372 { (unsigned) -1, insn_ds (62, 2, 1, 24, 0), 1 },
373
374 /* addis r12, r2, <any> */
375 { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
376
377 /* ld r12, <any>(r12) */
378 { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 12, 0, 0), 0 },
379
380 /* mtctr r12 */
381 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
382
383 /* bctr */
384 { (unsigned) -1, 0x4e800420, 0 },
385
386 { 0, 0, 0 }
387 };
388
389 /* Power 10 ELFv2 PLT call stubs */
390 static const struct ppc_insn_pattern ppc64_standard_linkage9[] =
391 {
392 /* std %r2,0+40(%r1) <optional> */
393 { insn_ds (-1, -1, -1, 0, 1), insn_ds (62, 2, 1, 40, 0), 1 },
394
395 /* pld r12, <any> */
396 { prefix (-1, -1, 1, 0), prefix (0, 0, 1, 0), 0 },
397 { insn_d (-1, -1, -1, 0), insn_d (57, 12, 0, 0), 0 },
398
399 /* mtctr r12 */
400 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
401
402 /* bctr */
403 { (unsigned) -1, 0x4e800420, 0 },
404
405 { 0, 0, 0 }
406 };
407
408 static const struct ppc_insn_pattern ppc64_standard_linkage10[] =
409 {
410 /* std %r2,0+40(%r1) <optional> */
411 { insn_ds (-1, -1, -1, 0, 1), insn_ds (62, 2, 1, 40, 0), 1 },
412
413 /* paddi r12,<any> */
414 { prefix (-1, -1, 1, 0), prefix (2, 0, 1, 0), 0 },
415 { insn_d (-1, -1, -1, 0), insn_d (14, 12, 0, 0), 0 },
416
417 /* mtctr r12 <optional> */
418 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
419
420 /* bctr */
421 { (unsigned) -1, 0x4e800420, 0 },
422
423 { 0, 0, 0 }
424 };
425
426 static const struct ppc_insn_pattern ppc64_standard_linkage11[] =
427 {
428 /* std %r2,0+40(%r1) <optional> */
429 { insn_ds (-1, -1, -1, 0, 1), insn_ds (62, 2, 1, 40, 0), 1 },
430
431 /* li %r11,0 <optional> */
432 { insn_d (-1, -1, -1, 0), insn_d (14, 11, 0, 0), 1 },
433
434 /* sldi %r11,%r11,34 <eq to rldicr rx,ry,n, 63-n> <optional> */
435 { insn_md (-1, -1, -1, 0, 0, 1), insn_md (30, 11, 11, 34, 63-34, 0), 1 },
436
437 /* paddi r12, <any> */
438 { prefix (-1, -1, 1, 0), prefix (2, 0, 1, 0), 0 },
439 { insn_d (-1, -1, -1, 0), insn_d (14, 12, 0, 0), 0 },
440
441 /* ldx %r12,%r11,%r12 <optional> */
442 { (unsigned) -1, insn_x (31, 12, 11, 12, 21), 1 },
443
444 /* add %r12,%r11,%r12 <optional> */
445 { (unsigned) -1, insn_xo (31, 12, 11, 12, 0, 0, 40), 1 },
446
447 /* mtctr r12 */
448 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
449
450 /* bctr */ // 13, 14, 15, 16
451 { (unsigned) -1, 0x4e800420, 0 },
452
453 { 0, 0, 0 }
454 };
455
456 static const struct ppc_insn_pattern ppc64_standard_linkage12[] =
457 {
458 /* std %r2,0+40(%r1) <optional> */
459 { insn_ds (-1, -1, -1, 0, 1), insn_ds (62, 2, 1, 40, 0), 1 },
460
461 /* lis %r11,xxx@ha <equivalent addis rx, 0, val> */
462 /* addis r12, r2, <any> */
463 { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 },
464
465 /* ori %r11,%r11,xxx@l */
466 { insn_d (-1, -1, -1, 0), insn_d (24, 11, 11, 0), 0 },
467
468 /* sldi %r11,%r11,34 <optional> */
469 { (unsigned) -1, insn_md (30, 11, 11, 34, 63-34, 0), 1 },
470
471 /*paddi r12,<any> */
472 { prefix (-1, -1, 1, 0), prefix (2, 0, 1, 0), 0 },
473 { insn_d (-1, -1, -1, 0), insn_d (14, 12, 0, 0), 0 },
474
475 /* sldi %r11,%r11,34 <optional> */
476 { (unsigned) -1, insn_md (30, 11, 11, 34, 63-34, 0), 1 },
477
478 /* ldx %r12,%r11,%r12 <optional> */
479 { (unsigned) -1, insn_x (31, 12, 11, 12, 21), 1 },
480
481 /* add %r12,%r11,%r12 <optional> */
482 { (unsigned) -1, insn_xo (31, 12, 11, 12, 0, 0, 40), 1 },
483
484 /* mtctr r12 */
485 { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 },
486
487 /* bctr */ // 17, 18, 19, 20
488 { (unsigned) -1, 0x4e800420, 0 },
489
490 { 0, 0, 0 }
491 };
492
493 /* When the dynamic linker is doing lazy symbol resolution, the first
494 call to a function in another object will go like this:
495
496 - The user's function calls the linkage function:
497
498 100003d4: 4b ff ff ad bl 10000380 <nnnn.plt_call.printf>
499 100003d8: e8 41 00 28 ld r2,40(r1)
500
501 - The linkage function loads the entry point and toc pointer from
502 the function descriptor in the PLT, and jumps to it:
503
504 <nnnn.plt_call.printf>:
505 10000380: f8 41 00 28 std r2,40(r1)
506 10000384: e9 62 80 78 ld r11,-32648(r2)
507 10000388: 7d 69 03 a6 mtctr r11
508 1000038c: e8 42 80 80 ld r2,-32640(r2)
509 10000390: 28 22 00 00 cmpldi r2,0
510 10000394: 4c e2 04 20 bnectr+
511 10000398: 48 00 03 a0 b 10000738 <printf@plt>
512
513 - But since this is the first time that PLT entry has been used, it
514 sends control to its glink entry. That loads the number of the
515 PLT entry and jumps to the common glink0 code:
516
517 <printf@plt>:
518 10000738: 38 00 00 01 li r0,1
519 1000073c: 4b ff ff bc b 100006f8 <__glink_PLTresolve>
520
521 - The common glink0 code then transfers control to the dynamic
522 linker's fixup code:
523
524 100006f0: 0000000000010440 .quad plt0 - (. + 16)
525 <__glink_PLTresolve>:
526 100006f8: 7d 88 02 a6 mflr r12
527 100006fc: 42 9f 00 05 bcl 20,4*cr7+so,10000700
528 10000700: 7d 68 02 a6 mflr r11
529 10000704: e8 4b ff f0 ld r2,-16(r11)
530 10000708: 7d 88 03 a6 mtlr r12
531 1000070c: 7d 82 5a 14 add r12,r2,r11
532 10000710: e9 6c 00 00 ld r11,0(r12)
533 10000714: e8 4c 00 08 ld r2,8(r12)
534 10000718: 7d 69 03 a6 mtctr r11
535 1000071c: e9 6c 00 10 ld r11,16(r12)
536 10000720: 4e 80 04 20 bctr
537
538 Eventually, this code will figure out how to skip all of this,
539 including the dynamic linker. At the moment, we just get through
540 the linkage function. */
541
542 /* If the current thread is about to execute a series of instructions
543 matching the ppc64_standard_linkage pattern, and INSN is the result
544 from that pattern match, return the code address to which the
545 standard linkage function will send them. (This doesn't deal with
546 dynamic linker lazy symbol resolution stubs.) */
547
548 static CORE_ADDR
ppc64_standard_linkage1_target(struct frame_info * frame,unsigned int * insn)549 ppc64_standard_linkage1_target (struct frame_info *frame, unsigned int *insn)
550 {
551 CORE_ADDR plt_off = ((ppc_insn_d_field (insn[0]) << 16)
552 + ppc_insn_ds_field (insn[2]));
553
554 return ppc64_plt_entry_point (frame, plt_off);
555 }
556
557 static CORE_ADDR
ppc64_standard_linkage2_target(struct frame_info * frame,unsigned int * insn)558 ppc64_standard_linkage2_target (struct frame_info *frame, unsigned int *insn)
559 {
560 CORE_ADDR plt_off = ((ppc_insn_d_field (insn[1]) << 16)
561 + ppc_insn_ds_field (insn[3]));
562
563 return ppc64_plt_entry_point (frame, plt_off);
564 }
565
566 static CORE_ADDR
ppc64_standard_linkage3_target(struct frame_info * frame,unsigned int * insn)567 ppc64_standard_linkage3_target (struct frame_info *frame, unsigned int *insn)
568 {
569 CORE_ADDR plt_off = ppc_insn_ds_field (insn[1]);
570
571 return ppc64_plt_entry_point (frame, plt_off);
572 }
573
574 static CORE_ADDR
ppc64_standard_linkage4_target(struct frame_info * frame,unsigned int * insn)575 ppc64_standard_linkage4_target (struct frame_info *frame, unsigned int *insn)
576 {
577 CORE_ADDR plt_off = ((ppc_insn_d_field (insn[1]) << 16)
578 + ppc_insn_ds_field (insn[2]));
579
580 return ppc64_plt_entry_point (frame, plt_off);
581 }
582
583 static CORE_ADDR
ppc64_pcrel_linkage1_target(struct frame_info * frame,unsigned int * insn,CORE_ADDR pc)584 ppc64_pcrel_linkage1_target (struct frame_info *frame, unsigned int *insn,
585 CORE_ADDR pc)
586 {
587 /* insn[0] is for the std instruction. */
588 CORE_ADDR plt_off = ppc_insn_prefix_dform (insn[1], insn[2]);
589
590 return ppc64_plt_pcrel_entry_point (frame, plt_off, pc);
591 }
592
593 static CORE_ADDR
ppc64_pcrel_linkage2_target(struct frame_info * frame,unsigned int * insn,CORE_ADDR pc)594 ppc64_pcrel_linkage2_target (struct frame_info *frame, unsigned int *insn,
595 CORE_ADDR pc)
596 {
597 CORE_ADDR plt_off;
598
599 /* insn[0] is for the std instruction.
600 insn[1] is for the li r11 instruction */
601 plt_off = ppc_insn_prefix_dform (insn[2], insn[3]);
602
603 return ppc64_plt_pcrel_entry_point (frame, plt_off, pc);
604 }
605
606
607 /* Given that we've begun executing a call trampoline at PC, return
608 the entry point of the function the trampoline will go to.
609
610 When the execution direction is EXEC_REVERSE, scan backward to
611 check whether we are in the middle of a PLT stub. */
612
613 static CORE_ADDR
ppc64_skip_trampoline_code_1(struct frame_info * frame,CORE_ADDR pc)614 ppc64_skip_trampoline_code_1 (struct frame_info *frame, CORE_ADDR pc)
615 {
616 #define MAX(a,b) ((a) > (b) ? (a) : (b))
617 unsigned int insns[MAX (MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage1),
618 ARRAY_SIZE (ppc64_standard_linkage2)),
619 MAX (ARRAY_SIZE (ppc64_standard_linkage3),
620 ARRAY_SIZE (ppc64_standard_linkage4))),
621 MAX(MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage5),
622 ARRAY_SIZE (ppc64_standard_linkage6)),
623 MAX (ARRAY_SIZE (ppc64_standard_linkage7),
624 ARRAY_SIZE (ppc64_standard_linkage8))),
625 MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage9),
626 ARRAY_SIZE (ppc64_standard_linkage10)),
627 MAX (ARRAY_SIZE (ppc64_standard_linkage11),
628 ARRAY_SIZE (ppc64_standard_linkage12)))))
629
630 - 1];
631 CORE_ADDR target;
632 int scan_limit, i;
633
634 scan_limit = 1;
635 /* When reverse-debugging, scan backward to check whether we are
636 in the middle of trampoline code. */
637 if (execution_direction == EXEC_REVERSE)
638 scan_limit = ARRAY_SIZE (insns) - 1;
639
640 for (i = 0; i < scan_limit; i++)
641 {
642 if (i < ARRAY_SIZE (ppc64_standard_linkage12) - 1
643 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage12, insns))
644 pc = ppc64_pcrel_linkage1_target (frame, insns, pc);
645 else if (i < ARRAY_SIZE (ppc64_standard_linkage11) - 1
646 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage11, insns))
647 pc = ppc64_pcrel_linkage2_target (frame, insns, pc);
648 else if (i < ARRAY_SIZE (ppc64_standard_linkage10) - 1
649 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage10, insns))
650 pc = ppc64_pcrel_linkage1_target (frame, insns, pc);
651 else if (i < ARRAY_SIZE (ppc64_standard_linkage9) - 1
652 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage9, insns))
653 pc = ppc64_pcrel_linkage1_target (frame, insns, pc);
654 else if (i < ARRAY_SIZE (ppc64_standard_linkage8) - 1
655 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage8, insns))
656 pc = ppc64_standard_linkage4_target (frame, insns);
657 else if (i < ARRAY_SIZE (ppc64_standard_linkage7) - 1
658 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage7,
659 insns))
660 pc = ppc64_standard_linkage3_target (frame, insns);
661 else if (i < ARRAY_SIZE (ppc64_standard_linkage6) - 1
662 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage6,
663 insns))
664 pc = ppc64_standard_linkage4_target (frame, insns);
665 else if (i < ARRAY_SIZE (ppc64_standard_linkage5) - 1
666 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage5,
667 insns)
668 && (insns[8] != 0 || insns[9] != 0))
669 pc = ppc64_standard_linkage3_target (frame, insns);
670 else if (i < ARRAY_SIZE (ppc64_standard_linkage4) - 1
671 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage4,
672 insns)
673 && (insns[9] != 0 || insns[10] != 0))
674 pc = ppc64_standard_linkage4_target (frame, insns);
675 else if (i < ARRAY_SIZE (ppc64_standard_linkage3) - 1
676 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage3,
677 insns)
678 && (insns[8] != 0 || insns[9] != 0))
679 pc = ppc64_standard_linkage3_target (frame, insns);
680 else if (i < ARRAY_SIZE (ppc64_standard_linkage2) - 1
681 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage2,
682 insns)
683 && (insns[10] != 0 || insns[11] != 0))
684 pc = ppc64_standard_linkage2_target (frame, insns);
685 else if (i < ARRAY_SIZE (ppc64_standard_linkage1) - 1
686 && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage1,
687 insns))
688 pc = ppc64_standard_linkage1_target (frame, insns);
689 else
690 {
691 /* Scan backward one more instructions if doesn't match. */
692 pc -= 4;
693 continue;
694 }
695
696 /* The PLT descriptor will either point to the already resolved target
697 address, or else to a glink stub. As the latter carry synthetic @plt
698 symbols, find_solib_trampoline_target should be able to resolve them. */
699 target = find_solib_trampoline_target (frame, pc);
700 return target ? target : pc;
701 }
702
703 return 0;
704 }
705
706 /* Wrapper of ppc64_skip_trampoline_code_1 checking also
707 ppc_elfv2_skip_entrypoint. */
708
709 CORE_ADDR
ppc64_skip_trampoline_code(struct frame_info * frame,CORE_ADDR pc)710 ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc)
711 {
712 struct gdbarch *gdbarch = get_frame_arch (frame);
713
714 pc = ppc64_skip_trampoline_code_1 (frame, pc);
715 if (pc != 0 && gdbarch_skip_entrypoint_p (gdbarch))
716 pc = gdbarch_skip_entrypoint (gdbarch, pc);
717 return pc;
718 }
719
720 /* Support for convert_from_func_ptr_addr (ARCH, ADDR, TARG) on PPC64
721 GNU/Linux.
722
723 Usually a function pointer's representation is simply the address
724 of the function. On GNU/Linux on the PowerPC however, a function
725 pointer may be a pointer to a function descriptor.
726
727 For PPC64, a function descriptor is a TOC entry, in a data section,
728 which contains three words: the first word is the address of the
729 function, the second word is the TOC pointer (r2), and the third word
730 is the static chain value.
731
732 Throughout GDB it is currently assumed that a function pointer contains
733 the address of the function, which is not easy to fix. In addition, the
734 conversion of a function address to a function pointer would
735 require allocation of a TOC entry in the inferior's memory space,
736 with all its drawbacks. To be able to call C++ virtual methods in
737 the inferior (which are called via function pointers),
738 find_function_addr uses this function to get the function address
739 from a function pointer.
740
741 If ADDR points at what is clearly a function descriptor, transform
742 it into the address of the corresponding function, if needed. Be
743 conservative, otherwise GDB will do the transformation on any
744 random addresses such as occur when there is no symbol table. */
745
746 CORE_ADDR
ppc64_convert_from_func_ptr_addr(struct gdbarch * gdbarch,CORE_ADDR addr,struct target_ops * targ)747 ppc64_convert_from_func_ptr_addr (struct gdbarch *gdbarch,
748 CORE_ADDR addr,
749 struct target_ops *targ)
750 {
751 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
752 const struct target_section *s = target_section_by_addr (targ, addr);
753
754 /* Check if ADDR points to a function descriptor. */
755 if (s && strcmp (s->the_bfd_section->name, ".opd") == 0)
756 {
757 /* There may be relocations that need to be applied to the .opd
758 section. Unfortunately, this function may be called at a time
759 where these relocations have not yet been performed -- this can
760 happen for example shortly after a library has been loaded with
761 dlopen, but ld.so has not yet applied the relocations.
762
763 To cope with both the case where the relocation has been applied,
764 and the case where it has not yet been applied, we do *not* read
765 the (maybe) relocated value from target memory, but we instead
766 read the non-relocated value from the BFD, and apply the relocation
767 offset manually.
768
769 This makes the assumption that all .opd entries are always relocated
770 by the same offset the section itself was relocated. This should
771 always be the case for GNU/Linux executables and shared libraries.
772 Note that other kind of object files (e.g. those added via
773 add-symbol-files) will currently never end up here anyway, as this
774 function accesses *target* sections only; only the main exec and
775 shared libraries are ever added to the target. */
776
777 gdb_byte buf[8];
778 int res;
779
780 res = bfd_get_section_contents (s->the_bfd_section->owner,
781 s->the_bfd_section,
782 &buf, addr - s->addr, 8);
783 if (res != 0)
784 return (extract_unsigned_integer (buf, 8, byte_order)
785 - bfd_section_vma (s->the_bfd_section) + s->addr);
786 }
787
788 return addr;
789 }
790
791 /* A synthetic 'dot' symbols on ppc64 has the udata.p entry pointing
792 back to the original ELF symbol it was derived from. Get the size
793 from that symbol. */
794
795 void
ppc64_elf_make_msymbol_special(asymbol * sym,struct minimal_symbol * msym)796 ppc64_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym)
797 {
798 if ((sym->flags & BSF_SYNTHETIC) != 0 && sym->udata.p != NULL)
799 {
800 elf_symbol_type *elf_sym = (elf_symbol_type *) sym->udata.p;
801 SET_MSYMBOL_SIZE (msym, elf_sym->internal_elf_sym.st_size);
802 }
803 }
804