| 1 | /* Target-dependent code for GNU/Linux on Alpha. |
| 2 | Copyright (C) 2002-2019 Free Software Foundation, Inc. |
| 3 | |
| 4 | This file is part of GDB. |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 3 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License |
| 17 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 18 | |
| 19 | #include "defs.h" |
| 20 | #include "frame.h" |
| 21 | #include "osabi.h" |
| 22 | #include "solib-svr4.h" |
| 23 | #include "symtab.h" |
| 24 | #include "regset.h" |
| 25 | #include "regcache.h" |
| 26 | #include "linux-tdep.h" |
| 27 | #include "alpha-tdep.h" |
| 28 | #include "gdbarch.h" |
| 29 | |
| 30 | /* This enum represents the signals' numbers on the Alpha |
| 31 | architecture. It just contains the signal definitions which are |
| 32 | different from the generic implementation. |
| 33 | |
| 34 | It is derived from the file <arch/alpha/include/uapi/asm/signal.h>, |
| 35 | from the Linux kernel tree. */ |
| 36 | |
| 37 | enum |
| 38 | { |
| 39 | /* SIGABRT is the same as in the generic implementation, but is |
| 40 | defined here because SIGIOT depends on it. */ |
| 41 | ALPHA_LINUX_SIGABRT = 6, |
| 42 | ALPHA_LINUX_SIGEMT = 7, |
| 43 | ALPHA_LINUX_SIGBUS = 10, |
| 44 | ALPHA_LINUX_SIGSYS = 12, |
| 45 | ALPHA_LINUX_SIGURG = 16, |
| 46 | ALPHA_LINUX_SIGSTOP = 17, |
| 47 | ALPHA_LINUX_SIGTSTP = 18, |
| 48 | ALPHA_LINUX_SIGCONT = 19, |
| 49 | ALPHA_LINUX_SIGCHLD = 20, |
| 50 | ALPHA_LINUX_SIGIO = 23, |
| 51 | ALPHA_LINUX_SIGINFO = 29, |
| 52 | ALPHA_LINUX_SIGUSR1 = 30, |
| 53 | ALPHA_LINUX_SIGUSR2 = 31, |
| 54 | ALPHA_LINUX_SIGPOLL = ALPHA_LINUX_SIGIO, |
| 55 | ALPHA_LINUX_SIGPWR = ALPHA_LINUX_SIGINFO, |
| 56 | ALPHA_LINUX_SIGIOT = ALPHA_LINUX_SIGABRT, |
| 57 | }; |
| 58 | |
| 59 | /* Under GNU/Linux, signal handler invocations can be identified by |
| 60 | the designated code sequence that is used to return from a signal |
| 61 | handler. In particular, the return address of a signal handler |
| 62 | points to a sequence that copies $sp to $16, loads $0 with the |
| 63 | appropriate syscall number, and finally enters the kernel. |
| 64 | |
| 65 | This is somewhat complicated in that: |
| 66 | (1) the expansion of the "mov" assembler macro has changed over |
| 67 | time, from "bis src,src,dst" to "bis zero,src,dst", |
| 68 | (2) the kernel has changed from using "addq" to "lda" to load the |
| 69 | syscall number, |
| 70 | (3) there is a "normal" sigreturn and an "rt" sigreturn which |
| 71 | has a different stack layout. */ |
| 72 | |
| 73 | static long |
| 74 | alpha_linux_sigtramp_offset_1 (struct gdbarch *gdbarch, CORE_ADDR pc) |
| 75 | { |
| 76 | switch (alpha_read_insn (gdbarch, pc)) |
| 77 | { |
| 78 | case 0x47de0410: /* bis $30,$30,$16 */ |
| 79 | case 0x47fe0410: /* bis $31,$30,$16 */ |
| 80 | return 0; |
| 81 | |
| 82 | case 0x43ecf400: /* addq $31,103,$0 */ |
| 83 | case 0x201f0067: /* lda $0,103($31) */ |
| 84 | case 0x201f015f: /* lda $0,351($31) */ |
| 85 | return 4; |
| 86 | |
| 87 | case 0x00000083: /* call_pal callsys */ |
| 88 | return 8; |
| 89 | |
| 90 | default: |
| 91 | return -1; |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | static LONGEST |
| 96 | alpha_linux_sigtramp_offset (struct gdbarch *gdbarch, CORE_ADDR pc) |
| 97 | { |
| 98 | long i, off; |
| 99 | |
| 100 | if (pc & 3) |
| 101 | return -1; |
| 102 | |
| 103 | /* Guess where we might be in the sequence. */ |
| 104 | off = alpha_linux_sigtramp_offset_1 (gdbarch, pc); |
| 105 | if (off < 0) |
| 106 | return -1; |
| 107 | |
| 108 | /* Verify that the other two insns of the sequence are as we expect. */ |
| 109 | pc -= off; |
| 110 | for (i = 0; i < 12; i += 4) |
| 111 | { |
| 112 | if (i == off) |
| 113 | continue; |
| 114 | if (alpha_linux_sigtramp_offset_1 (gdbarch, pc + i) != i) |
| 115 | return -1; |
| 116 | } |
| 117 | |
| 118 | return off; |
| 119 | } |
| 120 | |
| 121 | static int |
| 122 | alpha_linux_pc_in_sigtramp (struct gdbarch *gdbarch, |
| 123 | CORE_ADDR pc, const char *func_name) |
| 124 | { |
| 125 | return alpha_linux_sigtramp_offset (gdbarch, pc) >= 0; |
| 126 | } |
| 127 | |
| 128 | static CORE_ADDR |
| 129 | alpha_linux_sigcontext_addr (struct frame_info *this_frame) |
| 130 | { |
| 131 | struct gdbarch *gdbarch = get_frame_arch (this_frame); |
| 132 | CORE_ADDR pc; |
| 133 | ULONGEST sp; |
| 134 | long off; |
| 135 | |
| 136 | pc = get_frame_pc (this_frame); |
| 137 | sp = get_frame_register_unsigned (this_frame, ALPHA_SP_REGNUM); |
| 138 | |
| 139 | off = alpha_linux_sigtramp_offset (gdbarch, pc); |
| 140 | gdb_assert (off >= 0); |
| 141 | |
| 142 | /* __NR_rt_sigreturn has a couple of structures on the stack. This is: |
| 143 | |
| 144 | struct rt_sigframe { |
| 145 | struct siginfo info; |
| 146 | struct ucontext uc; |
| 147 | }; |
| 148 | |
| 149 | offsetof (struct rt_sigframe, uc.uc_mcontext); */ |
| 150 | |
| 151 | if (alpha_read_insn (gdbarch, pc - off + 4) == 0x201f015f) |
| 152 | return sp + 176; |
| 153 | |
| 154 | /* __NR_sigreturn has the sigcontext structure at the top of the stack. */ |
| 155 | return sp; |
| 156 | } |
| 157 | |
| 158 | /* Supply register REGNUM from the buffer specified by GREGS and LEN |
| 159 | in the general-purpose register set REGSET to register cache |
| 160 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 161 | |
| 162 | static void |
| 163 | alpha_linux_supply_gregset (const struct regset *regset, |
| 164 | struct regcache *regcache, |
| 165 | int regnum, const void *gregs, size_t len) |
| 166 | { |
| 167 | const gdb_byte *regs = (const gdb_byte *) gregs; |
| 168 | |
| 169 | gdb_assert (len >= 32 * 8); |
| 170 | alpha_supply_int_regs (regcache, regnum, regs, regs + 31 * 8, |
| 171 | len >= 33 * 8 ? regs + 32 * 8 : NULL); |
| 172 | } |
| 173 | |
| 174 | /* Collect register REGNUM from the register cache REGCACHE and store |
| 175 | it in the buffer specified by GREGS and LEN as described by the |
| 176 | general-purpose register set REGSET. If REGNUM is -1, do this for |
| 177 | all registers in REGSET. */ |
| 178 | |
| 179 | static void |
| 180 | alpha_linux_collect_gregset (const struct regset *regset, |
| 181 | const struct regcache *regcache, |
| 182 | int regnum, void *gregs, size_t len) |
| 183 | { |
| 184 | gdb_byte *regs = (gdb_byte *) gregs; |
| 185 | |
| 186 | gdb_assert (len >= 32 * 8); |
| 187 | alpha_fill_int_regs (regcache, regnum, regs, regs + 31 * 8, |
| 188 | len >= 33 * 8 ? regs + 32 * 8 : NULL); |
| 189 | } |
| 190 | |
| 191 | /* Supply register REGNUM from the buffer specified by FPREGS and LEN |
| 192 | in the floating-point register set REGSET to register cache |
| 193 | REGCACHE. If REGNUM is -1, do this for all registers in REGSET. */ |
| 194 | |
| 195 | static void |
| 196 | alpha_linux_supply_fpregset (const struct regset *regset, |
| 197 | struct regcache *regcache, |
| 198 | int regnum, const void *fpregs, size_t len) |
| 199 | { |
| 200 | const gdb_byte *regs = (const gdb_byte *) fpregs; |
| 201 | |
| 202 | gdb_assert (len >= 32 * 8); |
| 203 | alpha_supply_fp_regs (regcache, regnum, regs, regs + 31 * 8); |
| 204 | } |
| 205 | |
| 206 | /* Collect register REGNUM from the register cache REGCACHE and store |
| 207 | it in the buffer specified by FPREGS and LEN as described by the |
| 208 | general-purpose register set REGSET. If REGNUM is -1, do this for |
| 209 | all registers in REGSET. */ |
| 210 | |
| 211 | static void |
| 212 | alpha_linux_collect_fpregset (const struct regset *regset, |
| 213 | const struct regcache *regcache, |
| 214 | int regnum, void *fpregs, size_t len) |
| 215 | { |
| 216 | gdb_byte *regs = (gdb_byte *) fpregs; |
| 217 | |
| 218 | gdb_assert (len >= 32 * 8); |
| 219 | alpha_fill_fp_regs (regcache, regnum, regs, regs + 31 * 8); |
| 220 | } |
| 221 | |
| 222 | static const struct regset alpha_linux_gregset = |
| 223 | { |
| 224 | NULL, |
| 225 | alpha_linux_supply_gregset, alpha_linux_collect_gregset |
| 226 | }; |
| 227 | |
| 228 | static const struct regset alpha_linux_fpregset = |
| 229 | { |
| 230 | NULL, |
| 231 | alpha_linux_supply_fpregset, alpha_linux_collect_fpregset |
| 232 | }; |
| 233 | |
| 234 | /* Iterate over core file register note sections. */ |
| 235 | |
| 236 | static void |
| 237 | alpha_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, |
| 238 | iterate_over_regset_sections_cb *cb, |
| 239 | void *cb_data, |
| 240 | const struct regcache *regcache) |
| 241 | { |
| 242 | cb (".reg", 32 * 8, 32 * 8, &alpha_linux_gregset, NULL, cb_data); |
| 243 | cb (".reg2", 32 * 8, 32 * 8, &alpha_linux_fpregset, NULL, cb_data); |
| 244 | } |
| 245 | |
| 246 | /* Implementation of `gdbarch_gdb_signal_from_target', as defined in |
| 247 | gdbarch.h. */ |
| 248 | |
| 249 | static enum gdb_signal |
| 250 | alpha_linux_gdb_signal_from_target (struct gdbarch *gdbarch, |
| 251 | int signal) |
| 252 | { |
| 253 | switch (signal) |
| 254 | { |
| 255 | case ALPHA_LINUX_SIGEMT: |
| 256 | return GDB_SIGNAL_EMT; |
| 257 | |
| 258 | case ALPHA_LINUX_SIGBUS: |
| 259 | return GDB_SIGNAL_BUS; |
| 260 | |
| 261 | case ALPHA_LINUX_SIGSYS: |
| 262 | return GDB_SIGNAL_SYS; |
| 263 | |
| 264 | case ALPHA_LINUX_SIGURG: |
| 265 | return GDB_SIGNAL_URG; |
| 266 | |
| 267 | case ALPHA_LINUX_SIGSTOP: |
| 268 | return GDB_SIGNAL_STOP; |
| 269 | |
| 270 | case ALPHA_LINUX_SIGTSTP: |
| 271 | return GDB_SIGNAL_TSTP; |
| 272 | |
| 273 | case ALPHA_LINUX_SIGCONT: |
| 274 | return GDB_SIGNAL_CONT; |
| 275 | |
| 276 | case ALPHA_LINUX_SIGCHLD: |
| 277 | return GDB_SIGNAL_CHLD; |
| 278 | |
| 279 | /* No way to differentiate between SIGIO and SIGPOLL. |
| 280 | Therefore, we just handle the first one. */ |
| 281 | case ALPHA_LINUX_SIGIO: |
| 282 | return GDB_SIGNAL_IO; |
| 283 | |
| 284 | /* No way to differentiate between SIGINFO and SIGPWR. |
| 285 | Therefore, we just handle the first one. */ |
| 286 | case ALPHA_LINUX_SIGINFO: |
| 287 | return GDB_SIGNAL_INFO; |
| 288 | |
| 289 | case ALPHA_LINUX_SIGUSR1: |
| 290 | return GDB_SIGNAL_USR1; |
| 291 | |
| 292 | case ALPHA_LINUX_SIGUSR2: |
| 293 | return GDB_SIGNAL_USR2; |
| 294 | } |
| 295 | |
| 296 | return linux_gdb_signal_from_target (gdbarch, signal); |
| 297 | } |
| 298 | |
| 299 | /* Implementation of `gdbarch_gdb_signal_to_target', as defined in |
| 300 | gdbarch.h. */ |
| 301 | |
| 302 | static int |
| 303 | alpha_linux_gdb_signal_to_target (struct gdbarch *gdbarch, |
| 304 | enum gdb_signal signal) |
| 305 | { |
| 306 | switch (signal) |
| 307 | { |
| 308 | case GDB_SIGNAL_EMT: |
| 309 | return ALPHA_LINUX_SIGEMT; |
| 310 | |
| 311 | case GDB_SIGNAL_BUS: |
| 312 | return ALPHA_LINUX_SIGBUS; |
| 313 | |
| 314 | case GDB_SIGNAL_SYS: |
| 315 | return ALPHA_LINUX_SIGSYS; |
| 316 | |
| 317 | case GDB_SIGNAL_URG: |
| 318 | return ALPHA_LINUX_SIGURG; |
| 319 | |
| 320 | case GDB_SIGNAL_STOP: |
| 321 | return ALPHA_LINUX_SIGSTOP; |
| 322 | |
| 323 | case GDB_SIGNAL_TSTP: |
| 324 | return ALPHA_LINUX_SIGTSTP; |
| 325 | |
| 326 | case GDB_SIGNAL_CONT: |
| 327 | return ALPHA_LINUX_SIGCONT; |
| 328 | |
| 329 | case GDB_SIGNAL_CHLD: |
| 330 | return ALPHA_LINUX_SIGCHLD; |
| 331 | |
| 332 | case GDB_SIGNAL_IO: |
| 333 | return ALPHA_LINUX_SIGIO; |
| 334 | |
| 335 | case GDB_SIGNAL_INFO: |
| 336 | return ALPHA_LINUX_SIGINFO; |
| 337 | |
| 338 | case GDB_SIGNAL_USR1: |
| 339 | return ALPHA_LINUX_SIGUSR1; |
| 340 | |
| 341 | case GDB_SIGNAL_USR2: |
| 342 | return ALPHA_LINUX_SIGUSR2; |
| 343 | |
| 344 | case GDB_SIGNAL_POLL: |
| 345 | return ALPHA_LINUX_SIGPOLL; |
| 346 | |
| 347 | case GDB_SIGNAL_PWR: |
| 348 | return ALPHA_LINUX_SIGPWR; |
| 349 | } |
| 350 | |
| 351 | return linux_gdb_signal_to_target (gdbarch, signal); |
| 352 | } |
| 353 | |
| 354 | static void |
| 355 | alpha_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) |
| 356 | { |
| 357 | struct gdbarch_tdep *tdep; |
| 358 | |
| 359 | linux_init_abi (info, gdbarch); |
| 360 | |
| 361 | /* Hook into the DWARF CFI frame unwinder. */ |
| 362 | alpha_dwarf2_init_abi (info, gdbarch); |
| 363 | |
| 364 | /* Hook into the MDEBUG frame unwinder. */ |
| 365 | alpha_mdebug_init_abi (info, gdbarch); |
| 366 | |
| 367 | tdep = gdbarch_tdep (gdbarch); |
| 368 | tdep->dynamic_sigtramp_offset = alpha_linux_sigtramp_offset; |
| 369 | tdep->sigcontext_addr = alpha_linux_sigcontext_addr; |
| 370 | tdep->pc_in_sigtramp = alpha_linux_pc_in_sigtramp; |
| 371 | tdep->jb_pc = 2; |
| 372 | tdep->jb_elt_size = 8; |
| 373 | |
| 374 | set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); |
| 375 | |
| 376 | set_solib_svr4_fetch_link_map_offsets |
| 377 | (gdbarch, svr4_lp64_fetch_link_map_offsets); |
| 378 | |
| 379 | /* Enable TLS support. */ |
| 380 | set_gdbarch_fetch_tls_load_module_address (gdbarch, |
| 381 | svr4_fetch_objfile_link_map); |
| 382 | |
| 383 | set_gdbarch_iterate_over_regset_sections |
| 384 | (gdbarch, alpha_linux_iterate_over_regset_sections); |
| 385 | |
| 386 | set_gdbarch_gdb_signal_from_target (gdbarch, |
| 387 | alpha_linux_gdb_signal_from_target); |
| 388 | set_gdbarch_gdb_signal_to_target (gdbarch, |
| 389 | alpha_linux_gdb_signal_to_target); |
| 390 | } |
| 391 | |
| 392 | void |
| 393 | _initialize_alpha_linux_tdep (void) |
| 394 | { |
| 395 | gdbarch_register_osabi (bfd_arch_alpha, 0, GDB_OSABI_LINUX, |
| 396 | alpha_linux_init_abi); |
| 397 | } |