1 /* Motorola m68k target-dependent support for GNU/Linux. 2 3 Copyright (C) 1996-2023 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 "gdbcore.h" 22 #include "frame.h" 23 #include "target.h" 24 #include "gdbtypes.h" 25 #include "osabi.h" 26 #include "regcache.h" 27 #include "objfiles.h" 28 #include "symtab.h" 29 #include "m68k-tdep.h" 30 #include "trad-frame.h" 31 #include "frame-unwind.h" 32 #include "glibc-tdep.h" 33 #include "solib-svr4.h" 34 #include "auxv.h" 35 #include "observable.h" 36 #include "elf/common.h" 37 #include "linux-tdep.h" 38 #include "regset.h" 39 40 /* Offsets (in target ints) into jmp_buf. */ 41 42 #define M68K_LINUX_JB_ELEMENT_SIZE 4 43 #define M68K_LINUX_JB_PC 7 44 45 /* Check whether insn1 and insn2 are parts of a signal trampoline. */ 46 47 #define IS_SIGTRAMP(insn1, insn2) \ 48 (/* addaw #20,sp; moveq #119,d0; trap #0 */ \ 49 (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \ 50 /* moveq #119,d0; trap #0 */ \ 51 || insn1 == 0x70774e40) 52 53 #define IS_RT_SIGTRAMP(insn1, insn2) \ 54 (/* movel #173,d0; trap #0 */ \ 55 (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \ 56 /* moveq #82,d0; notb d0; trap #0 */ \ 57 || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40)) 58 59 /* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For 60 the sake of m68k_linux_get_sigtramp_info we also distinguish between 61 non-RT and RT signal trampolines. */ 62 63 static int 64 m68k_linux_pc_in_sigtramp (frame_info_ptr this_frame) 65 { 66 struct gdbarch *gdbarch = get_frame_arch (this_frame); 67 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 68 gdb_byte buf[12]; 69 unsigned long insn0, insn1, insn2; 70 CORE_ADDR pc = get_frame_pc (this_frame); 71 72 if (!safe_frame_unwind_memory (this_frame, pc - 4, {buf, sizeof (buf)})) 73 return 0; 74 insn1 = extract_unsigned_integer (buf + 4, 4, byte_order); 75 insn2 = extract_unsigned_integer (buf + 8, 4, byte_order); 76 if (IS_SIGTRAMP (insn1, insn2)) 77 return 1; 78 if (IS_RT_SIGTRAMP (insn1, insn2)) 79 return 2; 80 81 insn0 = extract_unsigned_integer (buf, 4, byte_order); 82 if (IS_SIGTRAMP (insn0, insn1)) 83 return 1; 84 if (IS_RT_SIGTRAMP (insn0, insn1)) 85 return 2; 86 87 insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16); 88 insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16); 89 if (IS_SIGTRAMP (insn0, insn1)) 90 return 1; 91 if (IS_RT_SIGTRAMP (insn0, insn1)) 92 return 2; 93 94 return 0; 95 } 96 97 /* From <asm/sigcontext.h>. */ 98 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] = 99 { 100 2 * 4, /* %d0 */ 101 3 * 4, /* %d1 */ 102 -1, /* %d2 */ 103 -1, /* %d3 */ 104 -1, /* %d4 */ 105 -1, /* %d5 */ 106 -1, /* %d6 */ 107 -1, /* %d7 */ 108 4 * 4, /* %a0 */ 109 5 * 4, /* %a1 */ 110 -1, /* %a2 */ 111 -1, /* %a3 */ 112 -1, /* %a4 */ 113 -1, /* %a5 */ 114 -1, /* %fp */ 115 1 * 4, /* %sp */ 116 6 * 4, /* %sr */ 117 6 * 4 + 2, /* %pc */ 118 8 * 4, /* %fp0 */ 119 11 * 4, /* %fp1 */ 120 -1, /* %fp2 */ 121 -1, /* %fp3 */ 122 -1, /* %fp4 */ 123 -1, /* %fp5 */ 124 -1, /* %fp6 */ 125 -1, /* %fp7 */ 126 14 * 4, /* %fpcr */ 127 15 * 4, /* %fpsr */ 128 16 * 4 /* %fpiaddr */ 129 }; 130 131 static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] = 132 { 133 2 * 4, /* %d0 */ 134 3 * 4, /* %d1 */ 135 -1, /* %d2 */ 136 -1, /* %d3 */ 137 -1, /* %d4 */ 138 -1, /* %d5 */ 139 -1, /* %d6 */ 140 -1, /* %d7 */ 141 4 * 4, /* %a0 */ 142 5 * 4, /* %a1 */ 143 -1, /* %a2 */ 144 -1, /* %a3 */ 145 -1, /* %a4 */ 146 6 * 4, /* %a5 */ 147 -1, /* %fp */ 148 1 * 4, /* %sp */ 149 7 * 4, /* %sr */ 150 7 * 4 + 2, /* %pc */ 151 -1, /* %fp0 */ 152 -1, /* %fp1 */ 153 -1, /* %fp2 */ 154 -1, /* %fp3 */ 155 -1, /* %fp4 */ 156 -1, /* %fp5 */ 157 -1, /* %fp6 */ 158 -1, /* %fp7 */ 159 -1, /* %fpcr */ 160 -1, /* %fpsr */ 161 -1 /* %fpiaddr */ 162 }; 163 164 /* From <asm/ucontext.h>. */ 165 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] = 166 { 167 6 * 4, /* %d0 */ 168 7 * 4, /* %d1 */ 169 8 * 4, /* %d2 */ 170 9 * 4, /* %d3 */ 171 10 * 4, /* %d4 */ 172 11 * 4, /* %d5 */ 173 12 * 4, /* %d6 */ 174 13 * 4, /* %d7 */ 175 14 * 4, /* %a0 */ 176 15 * 4, /* %a1 */ 177 16 * 4, /* %a2 */ 178 17 * 4, /* %a3 */ 179 18 * 4, /* %a4 */ 180 19 * 4, /* %a5 */ 181 20 * 4, /* %fp */ 182 21 * 4, /* %sp */ 183 23 * 4, /* %sr */ 184 22 * 4, /* %pc */ 185 27 * 4, /* %fp0 */ 186 30 * 4, /* %fp1 */ 187 33 * 4, /* %fp2 */ 188 36 * 4, /* %fp3 */ 189 39 * 4, /* %fp4 */ 190 42 * 4, /* %fp5 */ 191 45 * 4, /* %fp6 */ 192 48 * 4, /* %fp7 */ 193 24 * 4, /* %fpcr */ 194 25 * 4, /* %fpsr */ 195 26 * 4 /* %fpiaddr */ 196 }; 197 198 199 /* Get info about saved registers in sigtramp. */ 200 201 struct m68k_linux_sigtramp_info 202 { 203 /* Address of sigcontext. */ 204 CORE_ADDR sigcontext_addr; 205 206 /* Offset of registers in `struct sigcontext'. */ 207 int *sc_reg_offset; 208 }; 209 210 /* Nonzero if running on uClinux. */ 211 static int target_is_uclinux; 212 213 static void 214 m68k_linux_inferior_created (inferior *inf) 215 { 216 /* Record that we will need to re-evaluate whether we are running on a 217 uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */ 218 target_is_uclinux = -1; 219 } 220 221 static struct m68k_linux_sigtramp_info 222 m68k_linux_get_sigtramp_info (frame_info_ptr this_frame) 223 { 224 struct gdbarch *gdbarch = get_frame_arch (this_frame); 225 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 226 CORE_ADDR sp; 227 struct m68k_linux_sigtramp_info info; 228 229 /* Determine whether we are running on a uClinux or normal GNU/Linux 230 target so we can use the correct sigcontext layouts. */ 231 if (target_is_uclinux == -1) 232 target_is_uclinux = linux_is_uclinux (); 233 234 sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM); 235 236 /* Get sigcontext address, it is the third parameter on the stack. */ 237 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4, byte_order); 238 239 if (m68k_linux_pc_in_sigtramp (this_frame) == 2) 240 info.sc_reg_offset = m68k_linux_ucontext_reg_offset; 241 else 242 info.sc_reg_offset = (target_is_uclinux 243 ? m68k_uclinux_sigcontext_reg_offset 244 : m68k_linux_sigcontext_reg_offset); 245 return info; 246 } 247 248 /* Signal trampolines. */ 249 250 static struct trad_frame_cache * 251 m68k_linux_sigtramp_frame_cache (frame_info_ptr this_frame, 252 void **this_cache) 253 { 254 struct frame_id this_id; 255 struct trad_frame_cache *cache; 256 struct gdbarch *gdbarch = get_frame_arch (this_frame); 257 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 258 struct m68k_linux_sigtramp_info info; 259 gdb_byte buf[4]; 260 int i; 261 262 if (*this_cache) 263 return (struct trad_frame_cache *) *this_cache; 264 265 cache = trad_frame_cache_zalloc (this_frame); 266 267 /* FIXME: cagney/2004-05-01: This is is long standing broken code. 268 The frame ID's code address should be the start-address of the 269 signal trampoline and not the current PC within that 270 trampoline. */ 271 get_frame_register (this_frame, M68K_SP_REGNUM, buf); 272 /* See the end of m68k_push_dummy_call. */ 273 this_id = frame_id_build (extract_unsigned_integer (buf, 4, byte_order) 274 - 4 + 8, get_frame_pc (this_frame)); 275 trad_frame_set_id (cache, this_id); 276 277 info = m68k_linux_get_sigtramp_info (this_frame); 278 279 for (i = 0; i < M68K_NUM_REGS; i++) 280 if (info.sc_reg_offset[i] != -1) 281 trad_frame_set_reg_addr (cache, i, 282 info.sigcontext_addr + info.sc_reg_offset[i]); 283 284 *this_cache = cache; 285 return cache; 286 } 287 288 static void 289 m68k_linux_sigtramp_frame_this_id (frame_info_ptr this_frame, 290 void **this_cache, 291 struct frame_id *this_id) 292 { 293 struct trad_frame_cache *cache = 294 m68k_linux_sigtramp_frame_cache (this_frame, this_cache); 295 trad_frame_get_id (cache, this_id); 296 } 297 298 static struct value * 299 m68k_linux_sigtramp_frame_prev_register (frame_info_ptr this_frame, 300 void **this_cache, 301 int regnum) 302 { 303 /* Make sure we've initialized the cache. */ 304 struct trad_frame_cache *cache = 305 m68k_linux_sigtramp_frame_cache (this_frame, this_cache); 306 return trad_frame_get_register (cache, this_frame, regnum); 307 } 308 309 static int 310 m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self, 311 frame_info_ptr this_frame, 312 void **this_prologue_cache) 313 { 314 return m68k_linux_pc_in_sigtramp (this_frame); 315 } 316 317 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind = 318 { 319 "m68k linux sigtramp", 320 SIGTRAMP_FRAME, 321 default_frame_unwind_stop_reason, 322 m68k_linux_sigtramp_frame_this_id, 323 m68k_linux_sigtramp_frame_prev_register, 324 NULL, 325 m68k_linux_sigtramp_frame_sniffer 326 }; 327 328 /* Register maps for supply/collect regset functions. */ 329 330 static const struct regcache_map_entry m68k_linux_gregmap[] = 331 { 332 { 7, M68K_D1_REGNUM, 4 }, /* d1 ... d7 */ 333 { 7, M68K_A0_REGNUM, 4 }, /* a0 ... a6 */ 334 { 1, M68K_D0_REGNUM, 4 }, 335 { 1, M68K_SP_REGNUM, 4 }, 336 { 1, REGCACHE_MAP_SKIP, 4 }, /* orig_d0 (skip) */ 337 { 1, M68K_PS_REGNUM, 4 }, 338 { 1, M68K_PC_REGNUM, 4 }, 339 /* Ignore 16-bit fields 'fmtvec' and '__fill'. */ 340 { 0 } 341 }; 342 343 #define M68K_LINUX_GREGS_SIZE (20 * 4) 344 345 static const struct regcache_map_entry m68k_linux_fpregmap[] = 346 { 347 { 8, M68K_FP0_REGNUM, 12 }, /* fp0 ... fp7 */ 348 { 1, M68K_FPC_REGNUM, 4 }, 349 { 1, M68K_FPS_REGNUM, 4 }, 350 { 1, M68K_FPI_REGNUM, 4 }, 351 { 0 } 352 }; 353 354 #define M68K_LINUX_FPREGS_SIZE (27 * 4) 355 356 /* Register sets. */ 357 358 static const struct regset m68k_linux_gregset = 359 { 360 m68k_linux_gregmap, 361 regcache_supply_regset, regcache_collect_regset 362 }; 363 364 static const struct regset m68k_linux_fpregset = 365 { 366 m68k_linux_fpregmap, 367 regcache_supply_regset, regcache_collect_regset 368 }; 369 370 /* Iterate over core file register note sections. */ 371 372 static void 373 m68k_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 374 iterate_over_regset_sections_cb *cb, 375 void *cb_data, 376 const struct regcache *regcache) 377 { 378 cb (".reg", M68K_LINUX_GREGS_SIZE, M68K_LINUX_GREGS_SIZE, &m68k_linux_gregset, 379 NULL, cb_data); 380 cb (".reg2", M68K_LINUX_FPREGS_SIZE, M68K_LINUX_FPREGS_SIZE, 381 &m68k_linux_fpregset, NULL, cb_data); 382 } 383 384 static void 385 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 386 { 387 m68k_gdbarch_tdep *tdep = gdbarch_tdep<m68k_gdbarch_tdep> (gdbarch); 388 389 linux_init_abi (info, gdbarch, 0); 390 391 tdep->jb_pc = M68K_LINUX_JB_PC; 392 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE; 393 394 /* GNU/Linux uses a calling convention that's similar to SVR4. It 395 returns integer values in %d0/%d1, pointer values in %a0 and 396 floating values in %fp0, just like SVR4, but uses %a1 to pass the 397 address to store a structure value. It also returns small 398 structures in registers instead of memory. */ 399 m68k_svr4_init_abi (info, gdbarch); 400 tdep->struct_value_regnum = M68K_A1_REGNUM; 401 tdep->struct_return = reg_struct_return; 402 403 set_gdbarch_decr_pc_after_break (gdbarch, 2); 404 405 frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind); 406 407 /* Shared library handling. */ 408 409 /* GNU/Linux uses SVR4-style shared libraries. */ 410 set_solib_svr4_fetch_link_map_offsets (gdbarch, 411 linux_ilp32_fetch_link_map_offsets); 412 413 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ 414 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 415 416 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 417 418 /* Core file support. */ 419 set_gdbarch_iterate_over_regset_sections 420 (gdbarch, m68k_linux_iterate_over_regset_sections); 421 422 /* Enable TLS support. */ 423 set_gdbarch_fetch_tls_load_module_address (gdbarch, 424 svr4_fetch_objfile_link_map); 425 } 426 427 void _initialize_m68k_linux_tdep (); 428 void 429 _initialize_m68k_linux_tdep () 430 { 431 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX, 432 m68k_linux_init_abi); 433 gdb::observers::inferior_created.attach (m68k_linux_inferior_created, 434 "m68k-linux-tdep"); 435 } 436