1 /* Target-dependent code for GNU/Linux running on the Fujitsu FR-V, 2 for GDB. 3 4 Copyright (C) 2004-2015 Free Software Foundation, Inc. 5 6 This file is part of GDB. 7 8 This program is free software; you can redistribute it and/or modify 9 it under the terms of the GNU General Public License as published by 10 the Free Software Foundation; either version 3 of the License, or 11 (at your option) any later version. 12 13 This program is distributed in the hope that it will be useful, 14 but WITHOUT ANY WARRANTY; without even the implied warranty of 15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 GNU General Public License for more details. 17 18 You should have received a copy of the GNU General Public License 19 along with this program. If not, see <http://www.gnu.org/licenses/>. */ 20 21 #include "defs.h" 22 #include "gdbcore.h" 23 #include "target.h" 24 #include "frame.h" 25 #include "osabi.h" 26 #include "regcache.h" 27 #include "elf-bfd.h" 28 #include "elf/frv.h" 29 #include "frv-tdep.h" 30 #include "trad-frame.h" 31 #include "frame-unwind.h" 32 #include "regset.h" 33 #include "linux-tdep.h" 34 35 /* Define the size (in bytes) of an FR-V instruction. */ 36 static const int frv_instr_size = 4; 37 38 enum { 39 NORMAL_SIGTRAMP = 1, 40 RT_SIGTRAMP = 2 41 }; 42 43 static int 44 frv_linux_pc_in_sigtramp (struct gdbarch *gdbarch, CORE_ADDR pc, 45 const char *name) 46 { 47 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 48 gdb_byte buf[frv_instr_size]; 49 LONGEST instr; 50 int retval = 0; 51 52 if (target_read_memory (pc, buf, sizeof buf) != 0) 53 return 0; 54 55 instr = extract_unsigned_integer (buf, sizeof buf, byte_order); 56 57 if (instr == 0x8efc0077) /* setlos #__NR_sigreturn, gr7 */ 58 retval = NORMAL_SIGTRAMP; 59 else if (instr == 0x8efc00ad) /* setlos #__NR_rt_sigreturn, gr7 */ 60 retval = RT_SIGTRAMP; 61 else 62 return 0; 63 64 if (target_read_memory (pc + frv_instr_size, buf, sizeof buf) != 0) 65 return 0; 66 instr = extract_unsigned_integer (buf, sizeof buf, byte_order); 67 if (instr != 0xc0700000) /* tira gr0, 0 */ 68 return 0; 69 70 /* If we get this far, we'll return a non-zero value, either 71 NORMAL_SIGTRAMP (1) or RT_SIGTRAMP (2). */ 72 return retval; 73 } 74 75 /* Given NEXT_FRAME, the "callee" frame of the sigtramp frame that we 76 wish to decode, and REGNO, one of the frv register numbers defined 77 in frv-tdep.h, return the address of the saved register (corresponding 78 to REGNO) in the sigtramp frame. Return -1 if the register is not 79 found in the sigtramp frame. The magic numbers in the code below 80 were computed by examining the following kernel structs: 81 82 From arch/frv/kernel/signal.c: 83 84 struct sigframe 85 { 86 void (*pretcode)(void); 87 int sig; 88 struct sigcontext sc; 89 unsigned long extramask[_NSIG_WORDS-1]; 90 uint32_t retcode[2]; 91 }; 92 93 struct rt_sigframe 94 { 95 void (*pretcode)(void); 96 int sig; 97 struct siginfo *pinfo; 98 void *puc; 99 struct siginfo info; 100 struct ucontext uc; 101 uint32_t retcode[2]; 102 }; 103 104 From include/asm-frv/ucontext.h: 105 106 struct ucontext { 107 unsigned long uc_flags; 108 struct ucontext *uc_link; 109 stack_t uc_stack; 110 struct sigcontext uc_mcontext; 111 sigset_t uc_sigmask; 112 }; 113 114 From include/asm-frv/signal.h: 115 116 typedef struct sigaltstack { 117 void *ss_sp; 118 int ss_flags; 119 size_t ss_size; 120 } stack_t; 121 122 From include/asm-frv/sigcontext.h: 123 124 struct sigcontext { 125 struct user_context sc_context; 126 unsigned long sc_oldmask; 127 } __attribute__((aligned(8))); 128 129 From include/asm-frv/registers.h: 130 struct user_int_regs 131 { 132 unsigned long psr; 133 unsigned long isr; 134 unsigned long ccr; 135 unsigned long cccr; 136 unsigned long lr; 137 unsigned long lcr; 138 unsigned long pc; 139 unsigned long __status; 140 unsigned long syscallno; 141 unsigned long orig_gr8; 142 unsigned long gner[2]; 143 unsigned long long iacc[1]; 144 145 union { 146 unsigned long tbr; 147 unsigned long gr[64]; 148 }; 149 }; 150 151 struct user_fpmedia_regs 152 { 153 unsigned long fr[64]; 154 unsigned long fner[2]; 155 unsigned long msr[2]; 156 unsigned long acc[8]; 157 unsigned char accg[8]; 158 unsigned long fsr[1]; 159 }; 160 161 struct user_context 162 { 163 struct user_int_regs i; 164 struct user_fpmedia_regs f; 165 166 void *extension; 167 } __attribute__((aligned(8))); */ 168 169 static LONGEST 170 frv_linux_sigcontext_reg_addr (struct frame_info *this_frame, int regno, 171 CORE_ADDR *sc_addr_cache_ptr) 172 { 173 struct gdbarch *gdbarch = get_frame_arch (this_frame); 174 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 175 CORE_ADDR sc_addr; 176 177 if (sc_addr_cache_ptr && *sc_addr_cache_ptr) 178 { 179 sc_addr = *sc_addr_cache_ptr; 180 } 181 else 182 { 183 CORE_ADDR pc, sp; 184 gdb_byte buf[4]; 185 int tramp_type; 186 187 pc = get_frame_pc (this_frame); 188 tramp_type = frv_linux_pc_in_sigtramp (gdbarch, pc, 0); 189 190 get_frame_register (this_frame, sp_regnum, buf); 191 sp = extract_unsigned_integer (buf, sizeof buf, byte_order); 192 193 if (tramp_type == NORMAL_SIGTRAMP) 194 { 195 /* For a normal sigtramp frame, the sigcontext struct starts 196 at SP + 8. */ 197 sc_addr = sp + 8; 198 } 199 else if (tramp_type == RT_SIGTRAMP) 200 { 201 /* For a realtime sigtramp frame, SP + 12 contains a pointer 202 to a ucontext struct. The ucontext struct contains a 203 sigcontext struct starting 24 bytes in. (The offset of 204 uc_mcontext within struct ucontext is derived as follows: 205 stack_t is a 12-byte struct and struct sigcontext is 206 8-byte aligned. This gives an offset of 8 + 12 + 4 (for 207 padding) = 24.) */ 208 if (target_read_memory (sp + 12, buf, sizeof buf) != 0) 209 { 210 warning (_("Can't read realtime sigtramp frame.")); 211 return 0; 212 } 213 sc_addr = extract_unsigned_integer (buf, sizeof buf, byte_order); 214 sc_addr += 24; 215 } 216 else 217 internal_error (__FILE__, __LINE__, _("not a signal trampoline")); 218 219 if (sc_addr_cache_ptr) 220 *sc_addr_cache_ptr = sc_addr; 221 } 222 223 switch (regno) 224 { 225 case psr_regnum : 226 return sc_addr + 0; 227 /* sc_addr + 4 has "isr", the Integer Status Register. */ 228 case ccr_regnum : 229 return sc_addr + 8; 230 case cccr_regnum : 231 return sc_addr + 12; 232 case lr_regnum : 233 return sc_addr + 16; 234 case lcr_regnum : 235 return sc_addr + 20; 236 case pc_regnum : 237 return sc_addr + 24; 238 /* sc_addr + 28 is __status, the exception status. 239 sc_addr + 32 is syscallno, the syscall number or -1. 240 sc_addr + 36 is orig_gr8, the original syscall arg #1. 241 sc_addr + 40 is gner[0]. 242 sc_addr + 44 is gner[1]. */ 243 case iacc0h_regnum : 244 return sc_addr + 48; 245 case iacc0l_regnum : 246 return sc_addr + 52; 247 default : 248 if (first_gpr_regnum <= regno && regno <= last_gpr_regnum) 249 return sc_addr + 56 + 4 * (regno - first_gpr_regnum); 250 else if (first_fpr_regnum <= regno && regno <= last_fpr_regnum) 251 return sc_addr + 312 + 4 * (regno - first_fpr_regnum); 252 else 253 return -1; /* not saved. */ 254 } 255 } 256 257 /* Signal trampolines. */ 258 259 static struct trad_frame_cache * 260 frv_linux_sigtramp_frame_cache (struct frame_info *this_frame, 261 void **this_cache) 262 { 263 struct gdbarch *gdbarch = get_frame_arch (this_frame); 264 struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch); 265 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 266 struct trad_frame_cache *cache; 267 CORE_ADDR addr; 268 gdb_byte buf[4]; 269 int regnum; 270 CORE_ADDR sc_addr_cache_val = 0; 271 struct frame_id this_id; 272 273 if (*this_cache) 274 return *this_cache; 275 276 cache = trad_frame_cache_zalloc (this_frame); 277 278 /* FIXME: cagney/2004-05-01: This is is long standing broken code. 279 The frame ID's code address should be the start-address of the 280 signal trampoline and not the current PC within that 281 trampoline. */ 282 get_frame_register (this_frame, sp_regnum, buf); 283 addr = extract_unsigned_integer (buf, sizeof buf, byte_order); 284 this_id = frame_id_build (addr, get_frame_pc (this_frame)); 285 trad_frame_set_id (cache, this_id); 286 287 for (regnum = 0; regnum < frv_num_regs; regnum++) 288 { 289 LONGEST reg_addr = frv_linux_sigcontext_reg_addr (this_frame, regnum, 290 &sc_addr_cache_val); 291 if (reg_addr != -1) 292 trad_frame_set_reg_addr (cache, regnum, reg_addr); 293 } 294 295 *this_cache = cache; 296 return cache; 297 } 298 299 static void 300 frv_linux_sigtramp_frame_this_id (struct frame_info *this_frame, 301 void **this_cache, 302 struct frame_id *this_id) 303 { 304 struct trad_frame_cache *cache 305 = frv_linux_sigtramp_frame_cache (this_frame, this_cache); 306 trad_frame_get_id (cache, this_id); 307 } 308 309 static struct value * 310 frv_linux_sigtramp_frame_prev_register (struct frame_info *this_frame, 311 void **this_cache, int regnum) 312 { 313 /* Make sure we've initialized the cache. */ 314 struct trad_frame_cache *cache 315 = frv_linux_sigtramp_frame_cache (this_frame, this_cache); 316 return trad_frame_get_register (cache, this_frame, regnum); 317 } 318 319 static int 320 frv_linux_sigtramp_frame_sniffer (const struct frame_unwind *self, 321 struct frame_info *this_frame, 322 void **this_cache) 323 { 324 struct gdbarch *gdbarch = get_frame_arch (this_frame); 325 CORE_ADDR pc = get_frame_pc (this_frame); 326 const char *name; 327 328 find_pc_partial_function (pc, &name, NULL, NULL); 329 if (frv_linux_pc_in_sigtramp (gdbarch, pc, name)) 330 return 1; 331 332 return 0; 333 } 334 335 static const struct frame_unwind frv_linux_sigtramp_frame_unwind = 336 { 337 SIGTRAMP_FRAME, 338 default_frame_unwind_stop_reason, 339 frv_linux_sigtramp_frame_this_id, 340 frv_linux_sigtramp_frame_prev_register, 341 NULL, 342 frv_linux_sigtramp_frame_sniffer 343 }; 344 345 /* The FRV kernel defines ELF_NGREG as 46. We add 2 in order to include 346 the loadmap addresses in the register set. (See below for more info.) */ 347 #define FRV_ELF_NGREG (46 + 2) 348 typedef unsigned char frv_elf_greg_t[4]; 349 typedef struct { frv_elf_greg_t reg[FRV_ELF_NGREG]; } frv_elf_gregset_t; 350 351 typedef unsigned char frv_elf_fpreg_t[4]; 352 typedef struct 353 { 354 frv_elf_fpreg_t fr[64]; 355 frv_elf_fpreg_t fner[2]; 356 frv_elf_fpreg_t msr[2]; 357 frv_elf_fpreg_t acc[8]; 358 unsigned char accg[8]; 359 frv_elf_fpreg_t fsr[1]; 360 } frv_elf_fpregset_t; 361 362 /* Register maps. */ 363 364 static const struct regcache_map_entry frv_linux_gregmap[] = 365 { 366 { 1, psr_regnum, 4 }, 367 { 1, REGCACHE_MAP_SKIP, 4 }, /* isr */ 368 { 1, ccr_regnum, 4 }, 369 { 1, cccr_regnum, 4 }, 370 { 1, lr_regnum, 4 }, 371 { 1, lcr_regnum, 4 }, 372 { 1, pc_regnum, 4 }, 373 { 1, REGCACHE_MAP_SKIP, 4 }, /* __status */ 374 { 1, REGCACHE_MAP_SKIP, 4 }, /* syscallno */ 375 { 1, REGCACHE_MAP_SKIP, 4 }, /* orig_gr8 */ 376 { 1, gner0_regnum, 4 }, 377 { 1, gner1_regnum, 4 }, 378 { 1, REGCACHE_MAP_SKIP, 8 }, /* iacc0 */ 379 { 1, tbr_regnum, 4 }, 380 { 31, first_gpr_regnum + 1, 4 }, /* gr1 ... gr31 */ 381 382 /* Technically, the loadmap addresses are not part of `pr_reg' as 383 found in the elf_prstatus struct. The fields which communicate 384 the loadmap address appear (by design) immediately after 385 `pr_reg' though, and the BFD function elf32_frv_grok_prstatus() 386 has been implemented to include these fields in the register 387 section that it extracts from the core file. So, for our 388 purposes, they may be viewed as registers. */ 389 390 { 1, fdpic_loadmap_exec_regnum, 4 }, 391 { 1, fdpic_loadmap_interp_regnum, 4 }, 392 { 0 } 393 }; 394 395 static const struct regcache_map_entry frv_linux_fpregmap[] = 396 { 397 { 64, first_fpr_regnum, 4 }, /* fr0 ... fr63 */ 398 { 1, fner0_regnum, 4 }, 399 { 1, fner1_regnum, 4 }, 400 { 1, msr0_regnum, 4 }, 401 { 1, msr1_regnum, 4 }, 402 { 8, acc0_regnum, 4 }, /* acc0 ... acc7 */ 403 { 1, accg0123_regnum, 4 }, 404 { 1, accg4567_regnum, 4 }, 405 { 1, fsr0_regnum, 4 }, 406 { 0 } 407 }; 408 409 /* Unpack an frv_elf_gregset_t into GDB's register cache. */ 410 411 static void 412 frv_linux_supply_gregset (const struct regset *regset, 413 struct regcache *regcache, 414 int regnum, const void *gregs, size_t len) 415 { 416 int regi; 417 char zerobuf[MAX_REGISTER_SIZE]; 418 419 memset (zerobuf, 0, MAX_REGISTER_SIZE); 420 421 /* gr0 always contains 0. Also, the kernel passes the TBR value in 422 this slot. */ 423 regcache_raw_supply (regcache, first_gpr_regnum, zerobuf); 424 425 /* Fill gr32, ..., gr63 with zeros. */ 426 for (regi = first_gpr_regnum + 32; regi <= last_gpr_regnum; regi++) 427 regcache_raw_supply (regcache, regi, zerobuf); 428 429 regcache_supply_regset (regset, regcache, regnum, gregs, len); 430 } 431 432 /* FRV Linux kernel register sets. */ 433 434 static const struct regset frv_linux_gregset = 435 { 436 frv_linux_gregmap, 437 frv_linux_supply_gregset, regcache_collect_regset 438 }; 439 440 static const struct regset frv_linux_fpregset = 441 { 442 frv_linux_fpregmap, 443 regcache_supply_regset, regcache_collect_regset 444 }; 445 446 static void 447 frv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 448 iterate_over_regset_sections_cb *cb, 449 void *cb_data, 450 const struct regcache *regcache) 451 { 452 cb (".reg", sizeof (frv_elf_gregset_t), &frv_linux_gregset, 453 NULL, cb_data); 454 cb (".reg2", sizeof (frv_elf_fpregset_t), &frv_linux_fpregset, 455 NULL, cb_data); 456 } 457 458 459 static void 460 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 461 { 462 linux_init_abi (info, gdbarch); 463 464 /* Set the sigtramp frame sniffer. */ 465 frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind); 466 467 set_gdbarch_iterate_over_regset_sections 468 (gdbarch, frv_linux_iterate_over_regset_sections); 469 } 470 471 static enum gdb_osabi 472 frv_linux_elf_osabi_sniffer (bfd *abfd) 473 { 474 int elf_flags; 475 476 elf_flags = elf_elfheader (abfd)->e_flags; 477 478 /* Assume GNU/Linux if using the FDPIC ABI. If/when another OS shows 479 up that uses this ABI, we'll need to start using .note sections 480 or some such. */ 481 if (elf_flags & EF_FRV_FDPIC) 482 return GDB_OSABI_LINUX; 483 else 484 return GDB_OSABI_UNKNOWN; 485 } 486 487 /* Provide a prototype to silence -Wmissing-prototypes. */ 488 void _initialize_frv_linux_tdep (void); 489 490 void 491 _initialize_frv_linux_tdep (void) 492 { 493 gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX, 494 frv_linux_init_abi); 495 gdbarch_register_osabi_sniffer (bfd_arch_frv, 496 bfd_target_elf_flavour, 497 frv_linux_elf_osabi_sniffer); 498 } 499