| 1 | /* Common target-dependent code for ppc64 GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 1986-2015 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 | ((((opcd) & 0x3f) << 26) \ |
| 34 | | (((rts) & 0x1f) << 21) \ |
| 35 | | (((ra) & 0x1f) << 16) \ |
| 36 | | ((d) & 0xffff)) |
| 37 | |
| 38 | #define insn_ds(opcd, rts, ra, d, xo) \ |
| 39 | ((((opcd) & 0x3f) << 26) \ |
| 40 | | (((rts) & 0x1f) << 21) \ |
| 41 | | (((ra) & 0x1f) << 16) \ |
| 42 | | ((d) & 0xfffc) \ |
| 43 | | ((xo) & 0x3)) |
| 44 | |
| 45 | #define insn_xfx(opcd, rts, spr, xo) \ |
| 46 | ((((opcd) & 0x3f) << 26) \ |
| 47 | | (((rts) & 0x1f) << 21) \ |
| 48 | | (((spr) & 0x1f) << 16) \ |
| 49 | | (((spr) & 0x3e0) << 6) \ |
| 50 | | (((xo) & 0x3ff) << 1)) |
| 51 | |
| 52 | /* If PLT is the address of a 64-bit PowerPC PLT entry, |
| 53 | return the function's entry point. */ |
| 54 | |
| 55 | static CORE_ADDR |
| 56 | ppc64_plt_entry_point (struct gdbarch *gdbarch, CORE_ADDR plt) |
| 57 | { |
| 58 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 59 | /* The first word of the PLT entry is the function entry point. */ |
| 60 | return (CORE_ADDR) read_memory_unsigned_integer (plt, 8, byte_order); |
| 61 | } |
| 62 | |
| 63 | /* Patterns for the standard linkage functions. These are built by |
| 64 | build_plt_stub in bfd/elf64-ppc.c. */ |
| 65 | |
| 66 | /* Old ELFv1 PLT call stub. */ |
| 67 | |
| 68 | static struct ppc_insn_pattern ppc64_standard_linkage1[] = |
| 69 | { |
| 70 | /* addis r12, r2, <any> */ |
| 71 | { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, |
| 72 | |
| 73 | /* std r2, 40(r1) */ |
| 74 | { -1, insn_ds (62, 2, 1, 40, 0), 0 }, |
| 75 | |
| 76 | /* ld r11, <any>(r12) */ |
| 77 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, |
| 78 | |
| 79 | /* addis r12, r12, 1 <optional> */ |
| 80 | { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 }, |
| 81 | |
| 82 | /* ld r2, <any>(r12) */ |
| 83 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 }, |
| 84 | |
| 85 | /* addis r12, r12, 1 <optional> */ |
| 86 | { insn_d (-1, -1, -1, -1), insn_d (15, 12, 12, 1), 1 }, |
| 87 | |
| 88 | /* mtctr r11 */ |
| 89 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 }, |
| 90 | |
| 91 | /* ld r11, <any>(r12) <optional> */ |
| 92 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 }, |
| 93 | |
| 94 | /* bctr */ |
| 95 | { -1, 0x4e800420, 0 }, |
| 96 | |
| 97 | { 0, 0, 0 } |
| 98 | }; |
| 99 | |
| 100 | /* ELFv1 PLT call stub to access PLT entries more than +/- 32k from r2. |
| 101 | Also supports older stub with different placement of std 2,40(1), |
| 102 | a stub that omits the std 2,40(1), and both versions of power7 |
| 103 | thread safety read barriers. Note that there are actually two more |
| 104 | instructions following "cmpldi r2, 0", "bnectr+" and "b <glink_i>", |
| 105 | but there isn't any need to match them. */ |
| 106 | |
| 107 | static struct ppc_insn_pattern ppc64_standard_linkage2[] = |
| 108 | { |
| 109 | /* std r2, 40(r1) <optional> */ |
| 110 | { -1, insn_ds (62, 2, 1, 40, 0), 1 }, |
| 111 | |
| 112 | /* addis r12, r2, <any> */ |
| 113 | { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, |
| 114 | |
| 115 | /* std r2, 40(r1) <optional> */ |
| 116 | { -1, insn_ds (62, 2, 1, 40, 0), 1 }, |
| 117 | |
| 118 | /* ld r11, <any>(r12) */ |
| 119 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 0 }, |
| 120 | |
| 121 | /* addi r12, r12, <any> <optional> */ |
| 122 | { insn_d (-1, -1, -1, 0), insn_d (14, 12, 12, 0), 1 }, |
| 123 | |
| 124 | /* mtctr r11 */ |
| 125 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 }, |
| 126 | |
| 127 | /* xor r11, r11, r11 <optional> */ |
| 128 | { -1, 0x7d6b5a78, 1 }, |
| 129 | |
| 130 | /* add r12, r12, r11 <optional> */ |
| 131 | { -1, 0x7d8c5a14, 1 }, |
| 132 | |
| 133 | /* ld r2, <any>(r12) */ |
| 134 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 12, 0, 0), 0 }, |
| 135 | |
| 136 | /* ld r11, <any>(r12) <optional> */ |
| 137 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 12, 0, 0), 1 }, |
| 138 | |
| 139 | /* bctr <optional> */ |
| 140 | { -1, 0x4e800420, 1 }, |
| 141 | |
| 142 | /* cmpldi r2, 0 <optional> */ |
| 143 | { -1, 0x28220000, 1 }, |
| 144 | |
| 145 | { 0, 0, 0 } |
| 146 | }; |
| 147 | |
| 148 | /* ELFv1 PLT call stub to access PLT entries within +/- 32k of r2. */ |
| 149 | |
| 150 | static struct ppc_insn_pattern ppc64_standard_linkage3[] = |
| 151 | { |
| 152 | /* std r2, 40(r1) <optional> */ |
| 153 | { -1, insn_ds (62, 2, 1, 40, 0), 1 }, |
| 154 | |
| 155 | /* ld r11, <any>(r2) */ |
| 156 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 0 }, |
| 157 | |
| 158 | /* addi r2, r2, <any> <optional> */ |
| 159 | { insn_d (-1, -1, -1, 0), insn_d (14, 2, 2, 0), 1 }, |
| 160 | |
| 161 | /* mtctr r11 */ |
| 162 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 11, 9, 467), 0 }, |
| 163 | |
| 164 | /* xor r11, r11, r11 <optional> */ |
| 165 | { -1, 0x7d6b5a78, 1 }, |
| 166 | |
| 167 | /* add r2, r2, r11 <optional> */ |
| 168 | { -1, 0x7c425a14, 1 }, |
| 169 | |
| 170 | /* ld r11, <any>(r2) <optional> */ |
| 171 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 1 }, |
| 172 | |
| 173 | /* ld r2, <any>(r2) */ |
| 174 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 2, 0, 0), 0 }, |
| 175 | |
| 176 | /* bctr <optional> */ |
| 177 | { -1, 0x4e800420, 1 }, |
| 178 | |
| 179 | /* cmpldi r2, 0 <optional> */ |
| 180 | { -1, 0x28220000, 1 }, |
| 181 | |
| 182 | { 0, 0, 0 } |
| 183 | }; |
| 184 | |
| 185 | /* ELFv1 PLT call stub to access PLT entries more than +/- 32k from r2. |
| 186 | A more modern variant of ppc64_standard_linkage2 differing in |
| 187 | register usage. */ |
| 188 | |
| 189 | static struct ppc_insn_pattern ppc64_standard_linkage4[] = |
| 190 | { |
| 191 | /* std r2, 40(r1) <optional> */ |
| 192 | { -1, insn_ds (62, 2, 1, 40, 0), 1 }, |
| 193 | |
| 194 | /* addis r11, r2, <any> */ |
| 195 | { insn_d (-1, -1, -1, 0), insn_d (15, 11, 2, 0), 0 }, |
| 196 | |
| 197 | /* ld r12, <any>(r11) */ |
| 198 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 11, 0, 0), 0 }, |
| 199 | |
| 200 | /* addi r11, r11, <any> <optional> */ |
| 201 | { insn_d (-1, -1, -1, 0), insn_d (14, 11, 11, 0), 1 }, |
| 202 | |
| 203 | /* mtctr r12 */ |
| 204 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 }, |
| 205 | |
| 206 | /* xor r2, r12, r12 <optional> */ |
| 207 | { -1, 0x7d826278, 1 }, |
| 208 | |
| 209 | /* add r11, r11, r2 <optional> */ |
| 210 | { -1, 0x7d6b1214, 1 }, |
| 211 | |
| 212 | /* ld r2, <any>(r11) */ |
| 213 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 11, 0, 0), 0 }, |
| 214 | |
| 215 | /* ld r11, <any>(r11) <optional> */ |
| 216 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 11, 0, 0), 1 }, |
| 217 | |
| 218 | /* bctr <optional> */ |
| 219 | { -1, 0x4e800420, 1 }, |
| 220 | |
| 221 | /* cmpldi r2, 0 <optional> */ |
| 222 | { -1, 0x28220000, 1 }, |
| 223 | |
| 224 | { 0, 0, 0 } |
| 225 | }; |
| 226 | |
| 227 | /* ELFv1 PLT call stub to access PLT entries within +/- 32k of r2. |
| 228 | A more modern variant of ppc64_standard_linkage3 differing in |
| 229 | register usage. */ |
| 230 | |
| 231 | static struct ppc_insn_pattern ppc64_standard_linkage5[] = |
| 232 | { |
| 233 | /* std r2, 40(r1) <optional> */ |
| 234 | { -1, insn_ds (62, 2, 1, 40, 0), 1 }, |
| 235 | |
| 236 | /* ld r12, <any>(r2) */ |
| 237 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 2, 0, 0), 0 }, |
| 238 | |
| 239 | /* addi r2, r2, <any> <optional> */ |
| 240 | { insn_d (-1, -1, -1, 0), insn_d (14, 2, 2, 0), 1 }, |
| 241 | |
| 242 | /* mtctr r12 */ |
| 243 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 }, |
| 244 | |
| 245 | /* xor r11, r12, r12 <optional> */ |
| 246 | { -1, 0x7d8b6278, 1 }, |
| 247 | |
| 248 | /* add r2, r2, r11 <optional> */ |
| 249 | { -1, 0x7c425a14, 1 }, |
| 250 | |
| 251 | /* ld r11, <any>(r2) <optional> */ |
| 252 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 11, 2, 0, 0), 1 }, |
| 253 | |
| 254 | /* ld r2, <any>(r2) */ |
| 255 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 2, 2, 0, 0), 0 }, |
| 256 | |
| 257 | /* bctr <optional> */ |
| 258 | { -1, 0x4e800420, 1 }, |
| 259 | |
| 260 | /* cmpldi r2, 0 <optional> */ |
| 261 | { -1, 0x28220000, 1 }, |
| 262 | |
| 263 | { 0, 0, 0 } |
| 264 | }; |
| 265 | |
| 266 | /* ELFv2 PLT call stub to access PLT entries more than +/- 32k from r2. */ |
| 267 | |
| 268 | static struct ppc_insn_pattern ppc64_standard_linkage6[] = |
| 269 | { |
| 270 | /* std r2, 24(r1) <optional> */ |
| 271 | { -1, insn_ds (62, 2, 1, 24, 0), 1 }, |
| 272 | |
| 273 | /* addis r11, r2, <any> */ |
| 274 | { insn_d (-1, -1, -1, 0), insn_d (15, 11, 2, 0), 0 }, |
| 275 | |
| 276 | /* ld r12, <any>(r11) */ |
| 277 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 11, 0, 0), 0 }, |
| 278 | |
| 279 | /* mtctr r12 */ |
| 280 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 }, |
| 281 | |
| 282 | /* bctr */ |
| 283 | { -1, 0x4e800420, 0 }, |
| 284 | |
| 285 | { 0, 0, 0 } |
| 286 | }; |
| 287 | |
| 288 | /* ELFv2 PLT call stub to access PLT entries within +/- 32k of r2. */ |
| 289 | |
| 290 | static struct ppc_insn_pattern ppc64_standard_linkage7[] = |
| 291 | { |
| 292 | /* std r2, 24(r1) <optional> */ |
| 293 | { -1, insn_ds (62, 2, 1, 24, 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 | /* mtctr r12 */ |
| 299 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 }, |
| 300 | |
| 301 | /* bctr */ |
| 302 | { -1, 0x4e800420, 0 }, |
| 303 | |
| 304 | { 0, 0, 0 } |
| 305 | }; |
| 306 | |
| 307 | /* ELFv2 PLT call stub to access PLT entries more than +/- 32k from r2, |
| 308 | supporting fusion. */ |
| 309 | |
| 310 | static struct ppc_insn_pattern ppc64_standard_linkage8[] = |
| 311 | { |
| 312 | /* std r2, 24(r1) <optional> */ |
| 313 | { -1, insn_ds (62, 2, 1, 24, 0), 1 }, |
| 314 | |
| 315 | /* addis r12, r2, <any> */ |
| 316 | { insn_d (-1, -1, -1, 0), insn_d (15, 12, 2, 0), 0 }, |
| 317 | |
| 318 | /* ld r12, <any>(r12) */ |
| 319 | { insn_ds (-1, -1, -1, 0, -1), insn_ds (58, 12, 12, 0, 0), 0 }, |
| 320 | |
| 321 | /* mtctr r12 */ |
| 322 | { insn_xfx (-1, -1, -1, -1), insn_xfx (31, 12, 9, 467), 0 }, |
| 323 | |
| 324 | /* bctr */ |
| 325 | { -1, 0x4e800420, 0 }, |
| 326 | |
| 327 | { 0, 0, 0 } |
| 328 | }; |
| 329 | |
| 330 | /* When the dynamic linker is doing lazy symbol resolution, the first |
| 331 | call to a function in another object will go like this: |
| 332 | |
| 333 | - The user's function calls the linkage function: |
| 334 | |
| 335 | 100003d4: 4b ff ff ad bl 10000380 <nnnn.plt_call.printf> |
| 336 | 100003d8: e8 41 00 28 ld r2,40(r1) |
| 337 | |
| 338 | - The linkage function loads the entry point and toc pointer from |
| 339 | the function descriptor in the PLT, and jumps to it: |
| 340 | |
| 341 | <nnnn.plt_call.printf>: |
| 342 | 10000380: f8 41 00 28 std r2,40(r1) |
| 343 | 10000384: e9 62 80 78 ld r11,-32648(r2) |
| 344 | 10000388: 7d 69 03 a6 mtctr r11 |
| 345 | 1000038c: e8 42 80 80 ld r2,-32640(r2) |
| 346 | 10000390: 28 22 00 00 cmpldi r2,0 |
| 347 | 10000394: 4c e2 04 20 bnectr+ |
| 348 | 10000398: 48 00 03 a0 b 10000738 <printf@plt> |
| 349 | |
| 350 | - But since this is the first time that PLT entry has been used, it |
| 351 | sends control to its glink entry. That loads the number of the |
| 352 | PLT entry and jumps to the common glink0 code: |
| 353 | |
| 354 | <printf@plt>: |
| 355 | 10000738: 38 00 00 01 li r0,1 |
| 356 | 1000073c: 4b ff ff bc b 100006f8 <__glink_PLTresolve> |
| 357 | |
| 358 | - The common glink0 code then transfers control to the dynamic |
| 359 | linker's fixup code: |
| 360 | |
| 361 | 100006f0: 0000000000010440 .quad plt0 - (. + 16) |
| 362 | <__glink_PLTresolve>: |
| 363 | 100006f8: 7d 88 02 a6 mflr r12 |
| 364 | 100006fc: 42 9f 00 05 bcl 20,4*cr7+so,10000700 |
| 365 | 10000700: 7d 68 02 a6 mflr r11 |
| 366 | 10000704: e8 4b ff f0 ld r2,-16(r11) |
| 367 | 10000708: 7d 88 03 a6 mtlr r12 |
| 368 | 1000070c: 7d 82 5a 14 add r12,r2,r11 |
| 369 | 10000710: e9 6c 00 00 ld r11,0(r12) |
| 370 | 10000714: e8 4c 00 08 ld r2,8(r12) |
| 371 | 10000718: 7d 69 03 a6 mtctr r11 |
| 372 | 1000071c: e9 6c 00 10 ld r11,16(r12) |
| 373 | 10000720: 4e 80 04 20 bctr |
| 374 | |
| 375 | Eventually, this code will figure out how to skip all of this, |
| 376 | including the dynamic linker. At the moment, we just get through |
| 377 | the linkage function. */ |
| 378 | |
| 379 | /* If the current thread is about to execute a series of instructions |
| 380 | at PC matching the ppc64_standard_linkage pattern, and INSN is the result |
| 381 | from that pattern match, return the code address to which the |
| 382 | standard linkage function will send them. (This doesn't deal with |
| 383 | dynamic linker lazy symbol resolution stubs.) */ |
| 384 | |
| 385 | static CORE_ADDR |
| 386 | ppc64_standard_linkage1_target (struct frame_info *frame, |
| 387 | CORE_ADDR pc, unsigned int *insn) |
| 388 | { |
| 389 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 390 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 391 | |
| 392 | /* The address of the PLT entry this linkage function references. */ |
| 393 | CORE_ADDR plt |
| 394 | = ((CORE_ADDR) get_frame_register_unsigned (frame, |
| 395 | tdep->ppc_gp0_regnum + 2) |
| 396 | + (ppc_insn_d_field (insn[0]) << 16) |
| 397 | + ppc_insn_ds_field (insn[2])); |
| 398 | |
| 399 | return ppc64_plt_entry_point (gdbarch, plt); |
| 400 | } |
| 401 | |
| 402 | static CORE_ADDR |
| 403 | ppc64_standard_linkage2_target (struct frame_info *frame, |
| 404 | CORE_ADDR pc, unsigned int *insn) |
| 405 | { |
| 406 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 407 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 408 | |
| 409 | /* The address of the PLT entry this linkage function references. */ |
| 410 | CORE_ADDR plt |
| 411 | = ((CORE_ADDR) get_frame_register_unsigned (frame, |
| 412 | tdep->ppc_gp0_regnum + 2) |
| 413 | + (ppc_insn_d_field (insn[1]) << 16) |
| 414 | + ppc_insn_ds_field (insn[3])); |
| 415 | |
| 416 | return ppc64_plt_entry_point (gdbarch, plt); |
| 417 | } |
| 418 | |
| 419 | static CORE_ADDR |
| 420 | ppc64_standard_linkage3_target (struct frame_info *frame, |
| 421 | CORE_ADDR pc, unsigned int *insn) |
| 422 | { |
| 423 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 424 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 425 | |
| 426 | /* The address of the PLT entry this linkage function references. */ |
| 427 | CORE_ADDR plt |
| 428 | = ((CORE_ADDR) get_frame_register_unsigned (frame, |
| 429 | tdep->ppc_gp0_regnum + 2) |
| 430 | + ppc_insn_ds_field (insn[1])); |
| 431 | |
| 432 | return ppc64_plt_entry_point (gdbarch, plt); |
| 433 | } |
| 434 | |
| 435 | static CORE_ADDR |
| 436 | ppc64_standard_linkage4_target (struct frame_info *frame, |
| 437 | CORE_ADDR pc, unsigned int *insn) |
| 438 | { |
| 439 | struct gdbarch *gdbarch = get_frame_arch (frame); |
| 440 | struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); |
| 441 | |
| 442 | CORE_ADDR plt |
| 443 | = ((CORE_ADDR) get_frame_register_unsigned (frame, tdep->ppc_gp0_regnum + 2) |
| 444 | + (ppc_insn_d_field (insn[1]) << 16) |
| 445 | + ppc_insn_ds_field (insn[2])); |
| 446 | |
| 447 | return ppc64_plt_entry_point (gdbarch, plt); |
| 448 | } |
| 449 | |
| 450 | |
| 451 | /* Given that we've begun executing a call trampoline at PC, return |
| 452 | the entry point of the function the trampoline will go to. |
| 453 | |
| 454 | When the execution direction is EXEC_REVERSE, scan backward to |
| 455 | check whether we are in the middle of a PLT stub. */ |
| 456 | |
| 457 | CORE_ADDR |
| 458 | ppc64_skip_trampoline_code (struct frame_info *frame, CORE_ADDR pc) |
| 459 | { |
| 460 | #define MAX(a,b) ((a) > (b) ? (a) : (b)) |
| 461 | unsigned int insns[MAX (MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage1), |
| 462 | ARRAY_SIZE (ppc64_standard_linkage2)), |
| 463 | MAX (ARRAY_SIZE (ppc64_standard_linkage3), |
| 464 | ARRAY_SIZE (ppc64_standard_linkage4))), |
| 465 | MAX (MAX (ARRAY_SIZE (ppc64_standard_linkage5), |
| 466 | ARRAY_SIZE (ppc64_standard_linkage6)), |
| 467 | MAX (ARRAY_SIZE (ppc64_standard_linkage7), |
| 468 | ARRAY_SIZE (ppc64_standard_linkage8)))) |
| 469 | - 1]; |
| 470 | CORE_ADDR target; |
| 471 | int scan_limit, i; |
| 472 | |
| 473 | scan_limit = 1; |
| 474 | /* When reverse-debugging, scan backward to check whether we are |
| 475 | in the middle of trampoline code. */ |
| 476 | if (execution_direction == EXEC_REVERSE) |
| 477 | scan_limit = ARRAY_SIZE (insns) - 1; |
| 478 | |
| 479 | for (i = 0; i < scan_limit; i++) |
| 480 | { |
| 481 | if (i < ARRAY_SIZE (ppc64_standard_linkage8) - 1 |
| 482 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage8, insns)) |
| 483 | pc = ppc64_standard_linkage4_target (frame, pc, insns); |
| 484 | else if (i < ARRAY_SIZE (ppc64_standard_linkage7) - 1 |
| 485 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage7, |
| 486 | insns)) |
| 487 | pc = ppc64_standard_linkage3_target (frame, pc, insns); |
| 488 | else if (i < ARRAY_SIZE (ppc64_standard_linkage6) - 1 |
| 489 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage6, |
| 490 | insns)) |
| 491 | pc = ppc64_standard_linkage4_target (frame, pc, insns); |
| 492 | else if (i < ARRAY_SIZE (ppc64_standard_linkage5) - 1 |
| 493 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage5, |
| 494 | insns) |
| 495 | && (insns[8] != 0 || insns[9] != 0)) |
| 496 | pc = ppc64_standard_linkage3_target (frame, pc, insns); |
| 497 | else if (i < ARRAY_SIZE (ppc64_standard_linkage4) - 1 |
| 498 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage4, |
| 499 | insns) |
| 500 | && (insns[9] != 0 || insns[10] != 0)) |
| 501 | pc = ppc64_standard_linkage4_target (frame, pc, insns); |
| 502 | else if (i < ARRAY_SIZE (ppc64_standard_linkage3) - 1 |
| 503 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage3, |
| 504 | insns) |
| 505 | && (insns[8] != 0 || insns[9] != 0)) |
| 506 | pc = ppc64_standard_linkage3_target (frame, pc, insns); |
| 507 | else if (i < ARRAY_SIZE (ppc64_standard_linkage2) - 1 |
| 508 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage2, |
| 509 | insns) |
| 510 | && (insns[10] != 0 || insns[11] != 0)) |
| 511 | pc = ppc64_standard_linkage2_target (frame, pc, insns); |
| 512 | else if (i < ARRAY_SIZE (ppc64_standard_linkage1) - 1 |
| 513 | && ppc_insns_match_pattern (frame, pc, ppc64_standard_linkage1, |
| 514 | insns)) |
| 515 | pc = ppc64_standard_linkage1_target (frame, pc, insns); |
| 516 | else |
| 517 | { |
| 518 | /* Scan backward one more instructions if doesn't match. */ |
| 519 | pc -= 4; |
| 520 | continue; |
| 521 | } |
| 522 | |
| 523 | /* The PLT descriptor will either point to the already resolved target |
| 524 | address, or else to a glink stub. As the latter carry synthetic @plt |
| 525 | symbols, find_solib_trampoline_target should be able to resolve them. */ |
| 526 | target = find_solib_trampoline_target (frame, pc); |
| 527 | return target ? target : pc; |
| 528 | } |
| 529 | |
| 530 | return 0; |
| 531 | } |
| 532 | |
| 533 | /* Support for convert_from_func_ptr_addr (ARCH, ADDR, TARG) on PPC64 |
| 534 | GNU/Linux. |
| 535 | |
| 536 | Usually a function pointer's representation is simply the address |
| 537 | of the function. On GNU/Linux on the PowerPC however, a function |
| 538 | pointer may be a pointer to a function descriptor. |
| 539 | |
| 540 | For PPC64, a function descriptor is a TOC entry, in a data section, |
| 541 | which contains three words: the first word is the address of the |
| 542 | function, the second word is the TOC pointer (r2), and the third word |
| 543 | is the static chain value. |
| 544 | |
| 545 | Throughout GDB it is currently assumed that a function pointer contains |
| 546 | the address of the function, which is not easy to fix. In addition, the |
| 547 | conversion of a function address to a function pointer would |
| 548 | require allocation of a TOC entry in the inferior's memory space, |
| 549 | with all its drawbacks. To be able to call C++ virtual methods in |
| 550 | the inferior (which are called via function pointers), |
| 551 | find_function_addr uses this function to get the function address |
| 552 | from a function pointer. |
| 553 | |
| 554 | If ADDR points at what is clearly a function descriptor, transform |
| 555 | it into the address of the corresponding function, if needed. Be |
| 556 | conservative, otherwise GDB will do the transformation on any |
| 557 | random addresses such as occur when there is no symbol table. */ |
| 558 | |
| 559 | CORE_ADDR |
| 560 | ppc64_convert_from_func_ptr_addr (struct gdbarch *gdbarch, |
| 561 | CORE_ADDR addr, |
| 562 | struct target_ops *targ) |
| 563 | { |
| 564 | enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); |
| 565 | struct target_section *s = target_section_by_addr (targ, addr); |
| 566 | |
| 567 | /* Check if ADDR points to a function descriptor. */ |
| 568 | if (s && strcmp (s->the_bfd_section->name, ".opd") == 0) |
| 569 | { |
| 570 | /* There may be relocations that need to be applied to the .opd |
| 571 | section. Unfortunately, this function may be called at a time |
| 572 | where these relocations have not yet been performed -- this can |
| 573 | happen for example shortly after a library has been loaded with |
| 574 | dlopen, but ld.so has not yet applied the relocations. |
| 575 | |
| 576 | To cope with both the case where the relocation has been applied, |
| 577 | and the case where it has not yet been applied, we do *not* read |
| 578 | the (maybe) relocated value from target memory, but we instead |
| 579 | read the non-relocated value from the BFD, and apply the relocation |
| 580 | offset manually. |
| 581 | |
| 582 | This makes the assumption that all .opd entries are always relocated |
| 583 | by the same offset the section itself was relocated. This should |
| 584 | always be the case for GNU/Linux executables and shared libraries. |
| 585 | Note that other kind of object files (e.g. those added via |
| 586 | add-symbol-files) will currently never end up here anyway, as this |
| 587 | function accesses *target* sections only; only the main exec and |
| 588 | shared libraries are ever added to the target. */ |
| 589 | |
| 590 | gdb_byte buf[8]; |
| 591 | int res; |
| 592 | |
| 593 | res = bfd_get_section_contents (s->the_bfd_section->owner, |
| 594 | s->the_bfd_section, |
| 595 | &buf, addr - s->addr, 8); |
| 596 | if (res != 0) |
| 597 | return extract_unsigned_integer (buf, 8, byte_order) |
| 598 | - bfd_section_vma (s->bfd, s->the_bfd_section) + s->addr; |
| 599 | } |
| 600 | |
| 601 | return addr; |
| 602 | } |
| 603 | |
| 604 | /* A synthetic 'dot' symbols on ppc64 has the udata.p entry pointing |
| 605 | back to the original ELF symbol it was derived from. Get the size |
| 606 | from that symbol. */ |
| 607 | |
| 608 | void |
| 609 | ppc64_elf_make_msymbol_special (asymbol *sym, struct minimal_symbol *msym) |
| 610 | { |
| 611 | if ((sym->flags & BSF_SYNTHETIC) != 0 && sym->udata.p != NULL) |
| 612 | { |
| 613 | elf_symbol_type *elf_sym = (elf_symbol_type *) sym->udata.p; |
| 614 | SET_MSYMBOL_SIZE (msym, elf_sym->internal_elf_sym.st_size); |
| 615 | } |
| 616 | } |