1 /* Common target-dependent code for ppc64 GDB, the GNU debugger. 2 3 Copyright (C) 1986-2023 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 88 ppc64_plt_entry_point (frame_info_ptr 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 ppc_gdbarch_tdep *tdep = gdbarch_tdep<ppc_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 111 ppc64_plt_pcrel_entry_point (frame_info_ptr 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 549 ppc64_standard_linkage1_target (frame_info_ptr 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 558 ppc64_standard_linkage2_target (frame_info_ptr 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 567 ppc64_standard_linkage3_target (frame_info_ptr 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 575 ppc64_standard_linkage4_target (frame_info_ptr 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 584 ppc64_pcrel_linkage1_target (frame_info_ptr 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 594 ppc64_pcrel_linkage2_target (frame_info_ptr 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 614 ppc64_skip_trampoline_code_1 (frame_info_ptr 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 710 ppc64_skip_trampoline_code (frame_info_ptr 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 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 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 msym->set_size (elf_sym->internal_elf_sym.st_size); 802 } 803 } 804