1 /* Motorola m68k target-dependent support for GNU/Linux. 2 3 Copyright (C) 1996-2017 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 "doublest.h" 23 #include "floatformat.h" 24 #include "frame.h" 25 #include "target.h" 26 #include "gdbtypes.h" 27 #include "osabi.h" 28 #include "regcache.h" 29 #include "objfiles.h" 30 #include "symtab.h" 31 #include "m68k-tdep.h" 32 #include "trad-frame.h" 33 #include "frame-unwind.h" 34 #include "glibc-tdep.h" 35 #include "solib-svr4.h" 36 #include "auxv.h" 37 #include "observer.h" 38 #include "elf/common.h" 39 #include "linux-tdep.h" 40 #include "regset.h" 41 42 /* Offsets (in target ints) into jmp_buf. */ 43 44 #define M68K_LINUX_JB_ELEMENT_SIZE 4 45 #define M68K_LINUX_JB_PC 7 46 47 /* Check whether insn1 and insn2 are parts of a signal trampoline. */ 48 49 #define IS_SIGTRAMP(insn1, insn2) \ 50 (/* addaw #20,sp; moveq #119,d0; trap #0 */ \ 51 (insn1 == 0xdefc0014 && insn2 == 0x70774e40) \ 52 /* moveq #119,d0; trap #0 */ \ 53 || insn1 == 0x70774e40) 54 55 #define IS_RT_SIGTRAMP(insn1, insn2) \ 56 (/* movel #173,d0; trap #0 */ \ 57 (insn1 == 0x203c0000 && insn2 == 0x00ad4e40) \ 58 /* moveq #82,d0; notb d0; trap #0 */ \ 59 || (insn1 == 0x70524600 && (insn2 >> 16) == 0x4e40)) 60 61 /* Return non-zero if THIS_FRAME corresponds to a signal trampoline. For 62 the sake of m68k_linux_get_sigtramp_info we also distinguish between 63 non-RT and RT signal trampolines. */ 64 65 static int 66 m68k_linux_pc_in_sigtramp (struct frame_info *this_frame) 67 { 68 struct gdbarch *gdbarch = get_frame_arch (this_frame); 69 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 70 gdb_byte buf[12]; 71 unsigned long insn0, insn1, insn2; 72 CORE_ADDR pc = get_frame_pc (this_frame); 73 74 if (!safe_frame_unwind_memory (this_frame, pc - 4, buf, sizeof (buf))) 75 return 0; 76 insn1 = extract_unsigned_integer (buf + 4, 4, byte_order); 77 insn2 = extract_unsigned_integer (buf + 8, 4, byte_order); 78 if (IS_SIGTRAMP (insn1, insn2)) 79 return 1; 80 if (IS_RT_SIGTRAMP (insn1, insn2)) 81 return 2; 82 83 insn0 = extract_unsigned_integer (buf, 4, byte_order); 84 if (IS_SIGTRAMP (insn0, insn1)) 85 return 1; 86 if (IS_RT_SIGTRAMP (insn0, insn1)) 87 return 2; 88 89 insn0 = ((insn0 << 16) & 0xffffffff) | (insn1 >> 16); 90 insn1 = ((insn1 << 16) & 0xffffffff) | (insn2 >> 16); 91 if (IS_SIGTRAMP (insn0, insn1)) 92 return 1; 93 if (IS_RT_SIGTRAMP (insn0, insn1)) 94 return 2; 95 96 return 0; 97 } 98 99 /* From <asm/sigcontext.h>. */ 100 static int m68k_linux_sigcontext_reg_offset[M68K_NUM_REGS] = 101 { 102 2 * 4, /* %d0 */ 103 3 * 4, /* %d1 */ 104 -1, /* %d2 */ 105 -1, /* %d3 */ 106 -1, /* %d4 */ 107 -1, /* %d5 */ 108 -1, /* %d6 */ 109 -1, /* %d7 */ 110 4 * 4, /* %a0 */ 111 5 * 4, /* %a1 */ 112 -1, /* %a2 */ 113 -1, /* %a3 */ 114 -1, /* %a4 */ 115 -1, /* %a5 */ 116 -1, /* %fp */ 117 1 * 4, /* %sp */ 118 6 * 4, /* %sr */ 119 6 * 4 + 2, /* %pc */ 120 8 * 4, /* %fp0 */ 121 11 * 4, /* %fp1 */ 122 -1, /* %fp2 */ 123 -1, /* %fp3 */ 124 -1, /* %fp4 */ 125 -1, /* %fp5 */ 126 -1, /* %fp6 */ 127 -1, /* %fp7 */ 128 14 * 4, /* %fpcr */ 129 15 * 4, /* %fpsr */ 130 16 * 4 /* %fpiaddr */ 131 }; 132 133 static int m68k_uclinux_sigcontext_reg_offset[M68K_NUM_REGS] = 134 { 135 2 * 4, /* %d0 */ 136 3 * 4, /* %d1 */ 137 -1, /* %d2 */ 138 -1, /* %d3 */ 139 -1, /* %d4 */ 140 -1, /* %d5 */ 141 -1, /* %d6 */ 142 -1, /* %d7 */ 143 4 * 4, /* %a0 */ 144 5 * 4, /* %a1 */ 145 -1, /* %a2 */ 146 -1, /* %a3 */ 147 -1, /* %a4 */ 148 6 * 4, /* %a5 */ 149 -1, /* %fp */ 150 1 * 4, /* %sp */ 151 7 * 4, /* %sr */ 152 7 * 4 + 2, /* %pc */ 153 -1, /* %fp0 */ 154 -1, /* %fp1 */ 155 -1, /* %fp2 */ 156 -1, /* %fp3 */ 157 -1, /* %fp4 */ 158 -1, /* %fp5 */ 159 -1, /* %fp6 */ 160 -1, /* %fp7 */ 161 -1, /* %fpcr */ 162 -1, /* %fpsr */ 163 -1 /* %fpiaddr */ 164 }; 165 166 /* From <asm/ucontext.h>. */ 167 static int m68k_linux_ucontext_reg_offset[M68K_NUM_REGS] = 168 { 169 6 * 4, /* %d0 */ 170 7 * 4, /* %d1 */ 171 8 * 4, /* %d2 */ 172 9 * 4, /* %d3 */ 173 10 * 4, /* %d4 */ 174 11 * 4, /* %d5 */ 175 12 * 4, /* %d6 */ 176 13 * 4, /* %d7 */ 177 14 * 4, /* %a0 */ 178 15 * 4, /* %a1 */ 179 16 * 4, /* %a2 */ 180 17 * 4, /* %a3 */ 181 18 * 4, /* %a4 */ 182 19 * 4, /* %a5 */ 183 20 * 4, /* %fp */ 184 21 * 4, /* %sp */ 185 23 * 4, /* %sr */ 186 22 * 4, /* %pc */ 187 27 * 4, /* %fp0 */ 188 30 * 4, /* %fp1 */ 189 33 * 4, /* %fp2 */ 190 36 * 4, /* %fp3 */ 191 39 * 4, /* %fp4 */ 192 42 * 4, /* %fp5 */ 193 45 * 4, /* %fp6 */ 194 48 * 4, /* %fp7 */ 195 24 * 4, /* %fpcr */ 196 25 * 4, /* %fpsr */ 197 26 * 4 /* %fpiaddr */ 198 }; 199 200 201 /* Get info about saved registers in sigtramp. */ 202 203 struct m68k_linux_sigtramp_info 204 { 205 /* Address of sigcontext. */ 206 CORE_ADDR sigcontext_addr; 207 208 /* Offset of registers in `struct sigcontext'. */ 209 int *sc_reg_offset; 210 }; 211 212 /* Nonzero if running on uClinux. */ 213 static int target_is_uclinux; 214 215 static void 216 m68k_linux_inferior_created (struct target_ops *objfile, int from_tty) 217 { 218 /* Record that we will need to re-evaluate whether we are running on a 219 uClinux or normal GNU/Linux target (see m68k_linux_get_sigtramp_info). */ 220 target_is_uclinux = -1; 221 } 222 223 static struct m68k_linux_sigtramp_info 224 m68k_linux_get_sigtramp_info (struct frame_info *this_frame) 225 { 226 struct gdbarch *gdbarch = get_frame_arch (this_frame); 227 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 228 CORE_ADDR sp; 229 struct m68k_linux_sigtramp_info info; 230 231 /* Determine whether we are running on a uClinux or normal GNU/Linux 232 target so we can use the correct sigcontext layouts. */ 233 if (target_is_uclinux == -1) 234 target_is_uclinux = linux_is_uclinux (); 235 236 sp = get_frame_register_unsigned (this_frame, M68K_SP_REGNUM); 237 238 /* Get sigcontext address, it is the third parameter on the stack. */ 239 info.sigcontext_addr = read_memory_unsigned_integer (sp + 8, 4, byte_order); 240 241 if (m68k_linux_pc_in_sigtramp (this_frame) == 2) 242 info.sc_reg_offset = m68k_linux_ucontext_reg_offset; 243 else 244 info.sc_reg_offset = (target_is_uclinux 245 ? m68k_uclinux_sigcontext_reg_offset 246 : m68k_linux_sigcontext_reg_offset); 247 return info; 248 } 249 250 /* Signal trampolines. */ 251 252 static struct trad_frame_cache * 253 m68k_linux_sigtramp_frame_cache (struct frame_info *this_frame, 254 void **this_cache) 255 { 256 struct frame_id this_id; 257 struct trad_frame_cache *cache; 258 struct gdbarch *gdbarch = get_frame_arch (this_frame); 259 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 260 struct m68k_linux_sigtramp_info info; 261 gdb_byte buf[4]; 262 int i; 263 264 if (*this_cache) 265 return (struct trad_frame_cache *) *this_cache; 266 267 cache = trad_frame_cache_zalloc (this_frame); 268 269 /* FIXME: cagney/2004-05-01: This is is long standing broken code. 270 The frame ID's code address should be the start-address of the 271 signal trampoline and not the current PC within that 272 trampoline. */ 273 get_frame_register (this_frame, M68K_SP_REGNUM, buf); 274 /* See the end of m68k_push_dummy_call. */ 275 this_id = frame_id_build (extract_unsigned_integer (buf, 4, byte_order) 276 - 4 + 8, get_frame_pc (this_frame)); 277 trad_frame_set_id (cache, this_id); 278 279 info = m68k_linux_get_sigtramp_info (this_frame); 280 281 for (i = 0; i < M68K_NUM_REGS; i++) 282 if (info.sc_reg_offset[i] != -1) 283 trad_frame_set_reg_addr (cache, i, 284 info.sigcontext_addr + info.sc_reg_offset[i]); 285 286 *this_cache = cache; 287 return cache; 288 } 289 290 static void 291 m68k_linux_sigtramp_frame_this_id (struct frame_info *this_frame, 292 void **this_cache, 293 struct frame_id *this_id) 294 { 295 struct trad_frame_cache *cache = 296 m68k_linux_sigtramp_frame_cache (this_frame, this_cache); 297 trad_frame_get_id (cache, this_id); 298 } 299 300 static struct value * 301 m68k_linux_sigtramp_frame_prev_register (struct frame_info *this_frame, 302 void **this_cache, 303 int regnum) 304 { 305 /* Make sure we've initialized the cache. */ 306 struct trad_frame_cache *cache = 307 m68k_linux_sigtramp_frame_cache (this_frame, this_cache); 308 return trad_frame_get_register (cache, this_frame, regnum); 309 } 310 311 static int 312 m68k_linux_sigtramp_frame_sniffer (const struct frame_unwind *self, 313 struct frame_info *this_frame, 314 void **this_prologue_cache) 315 { 316 return m68k_linux_pc_in_sigtramp (this_frame); 317 } 318 319 static const struct frame_unwind m68k_linux_sigtramp_frame_unwind = 320 { 321 SIGTRAMP_FRAME, 322 default_frame_unwind_stop_reason, 323 m68k_linux_sigtramp_frame_this_id, 324 m68k_linux_sigtramp_frame_prev_register, 325 NULL, 326 m68k_linux_sigtramp_frame_sniffer 327 }; 328 329 /* Register maps for supply/collect regset functions. */ 330 331 static const struct regcache_map_entry m68k_linux_gregmap[] = 332 { 333 { 7, M68K_D1_REGNUM, 4 }, /* d1 ... d7 */ 334 { 7, M68K_A0_REGNUM, 4 }, /* a0 ... a6 */ 335 { 1, M68K_D0_REGNUM, 4 }, 336 { 1, M68K_SP_REGNUM, 4 }, 337 { 1, REGCACHE_MAP_SKIP, 4 }, /* orig_d0 (skip) */ 338 { 1, M68K_PS_REGNUM, 4 }, 339 { 1, M68K_PC_REGNUM, 4 }, 340 /* Ignore 16-bit fields 'fmtvec' and '__fill'. */ 341 { 0 } 342 }; 343 344 #define M68K_LINUX_GREGS_SIZE (20 * 4) 345 346 static const struct regcache_map_entry m68k_linux_fpregmap[] = 347 { 348 { 8, M68K_FP0_REGNUM, 12 }, /* fp0 ... fp7 */ 349 { 1, M68K_FPC_REGNUM, 4 }, 350 { 1, M68K_FPS_REGNUM, 4 }, 351 { 1, M68K_FPI_REGNUM, 4 }, 352 { 0 } 353 }; 354 355 #define M68K_LINUX_FPREGS_SIZE (27 * 4) 356 357 /* Register sets. */ 358 359 static const struct regset m68k_linux_gregset = 360 { 361 m68k_linux_gregmap, 362 regcache_supply_regset, regcache_collect_regset 363 }; 364 365 static const struct regset m68k_linux_fpregset = 366 { 367 m68k_linux_fpregmap, 368 regcache_supply_regset, regcache_collect_regset 369 }; 370 371 /* Iterate over core file register note sections. */ 372 373 static void 374 m68k_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 375 iterate_over_regset_sections_cb *cb, 376 void *cb_data, 377 const struct regcache *regcache) 378 { 379 cb (".reg", M68K_LINUX_GREGS_SIZE, &m68k_linux_gregset, NULL, cb_data); 380 cb (".reg2", M68K_LINUX_FPREGS_SIZE, &m68k_linux_fpregset, NULL, cb_data); 381 } 382 383 static void 384 m68k_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 385 { 386 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 387 388 linux_init_abi (info, gdbarch); 389 390 tdep->jb_pc = M68K_LINUX_JB_PC; 391 tdep->jb_elt_size = M68K_LINUX_JB_ELEMENT_SIZE; 392 393 /* GNU/Linux uses a calling convention that's similar to SVR4. It 394 returns integer values in %d0/%d1, pointer values in %a0 and 395 floating values in %fp0, just like SVR4, but uses %a1 to pass the 396 address to store a structure value. It also returns small 397 structures in registers instead of memory. */ 398 m68k_svr4_init_abi (info, gdbarch); 399 tdep->struct_value_regnum = M68K_A1_REGNUM; 400 tdep->struct_return = reg_struct_return; 401 402 set_gdbarch_decr_pc_after_break (gdbarch, 2); 403 404 frame_unwind_append_unwinder (gdbarch, &m68k_linux_sigtramp_frame_unwind); 405 406 /* Shared library handling. */ 407 408 /* GNU/Linux uses SVR4-style shared libraries. */ 409 set_solib_svr4_fetch_link_map_offsets (gdbarch, 410 svr4_ilp32_fetch_link_map_offsets); 411 412 /* GNU/Linux uses the dynamic linker included in the GNU C Library. */ 413 set_gdbarch_skip_solib_resolver (gdbarch, glibc_skip_solib_resolver); 414 415 set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target); 416 417 /* Core file support. */ 418 set_gdbarch_iterate_over_regset_sections 419 (gdbarch, m68k_linux_iterate_over_regset_sections); 420 421 /* Enable TLS support. */ 422 set_gdbarch_fetch_tls_load_module_address (gdbarch, 423 svr4_fetch_objfile_link_map); 424 } 425 426 /* Provide a prototype to silence -Wmissing-prototypes. */ 427 extern initialize_file_ftype _initialize_m68k_linux_tdep; 428 429 void 430 _initialize_m68k_linux_tdep (void) 431 { 432 gdbarch_register_osabi (bfd_arch_m68k, 0, GDB_OSABI_LINUX, 433 m68k_linux_init_abi); 434 observer_attach_inferior_created (m68k_linux_inferior_created); 435 } 436