1 /* Target-dependent code for GNU/Linux running on the Fujitsu FR-V, 2 for GDB. 3 4 Copyright (C) 2004-2020 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 #include "gdbarch.h" 35 36 /* Define the size (in bytes) of an FR-V instruction. */ 37 static const int frv_instr_size = 4; 38 39 enum { 40 NORMAL_SIGTRAMP = 1, 41 RT_SIGTRAMP = 2 42 }; 43 44 static int 45 frv_linux_pc_in_sigtramp (struct gdbarch *gdbarch, CORE_ADDR pc, 46 const char *name) 47 { 48 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 49 gdb_byte buf[frv_instr_size]; 50 LONGEST instr; 51 int retval = 0; 52 53 if (target_read_memory (pc, buf, sizeof buf) != 0) 54 return 0; 55 56 instr = extract_unsigned_integer (buf, sizeof buf, byte_order); 57 58 if (instr == 0x8efc0077) /* setlos #__NR_sigreturn, gr7 */ 59 retval = NORMAL_SIGTRAMP; 60 else if (instr == 0x8efc00ad) /* setlos #__NR_rt_sigreturn, gr7 */ 61 retval = RT_SIGTRAMP; 62 else 63 return 0; 64 65 if (target_read_memory (pc + frv_instr_size, buf, sizeof buf) != 0) 66 return 0; 67 instr = extract_unsigned_integer (buf, sizeof buf, byte_order); 68 if (instr != 0xc0700000) /* tira gr0, 0 */ 69 return 0; 70 71 /* If we get this far, we'll return a non-zero value, either 72 NORMAL_SIGTRAMP (1) or RT_SIGTRAMP (2). */ 73 return retval; 74 } 75 76 /* Given NEXT_FRAME, the "callee" frame of the sigtramp frame that we 77 wish to decode, and REGNO, one of the frv register numbers defined 78 in frv-tdep.h, return the address of the saved register (corresponding 79 to REGNO) in the sigtramp frame. Return -1 if the register is not 80 found in the sigtramp frame. The magic numbers in the code below 81 were computed by examining the following kernel structs: 82 83 From arch/frv/kernel/signal.c: 84 85 struct sigframe 86 { 87 void (*pretcode)(void); 88 int sig; 89 struct sigcontext sc; 90 unsigned long extramask[_NSIG_WORDS-1]; 91 uint32_t retcode[2]; 92 }; 93 94 struct rt_sigframe 95 { 96 void (*pretcode)(void); 97 int sig; 98 struct siginfo *pinfo; 99 void *puc; 100 struct siginfo info; 101 struct ucontext uc; 102 uint32_t retcode[2]; 103 }; 104 105 From include/asm-frv/ucontext.h: 106 107 struct ucontext { 108 unsigned long uc_flags; 109 struct ucontext *uc_link; 110 stack_t uc_stack; 111 struct sigcontext uc_mcontext; 112 sigset_t uc_sigmask; 113 }; 114 115 From include/asm-frv/signal.h: 116 117 typedef struct sigaltstack { 118 void *ss_sp; 119 int ss_flags; 120 size_t ss_size; 121 } stack_t; 122 123 From include/asm-frv/sigcontext.h: 124 125 struct sigcontext { 126 struct user_context sc_context; 127 unsigned long sc_oldmask; 128 } __attribute__((aligned(8))); 129 130 From include/asm-frv/registers.h: 131 struct user_int_regs 132 { 133 unsigned long psr; 134 unsigned long isr; 135 unsigned long ccr; 136 unsigned long cccr; 137 unsigned long lr; 138 unsigned long lcr; 139 unsigned long pc; 140 unsigned long __status; 141 unsigned long syscallno; 142 unsigned long orig_gr8; 143 unsigned long gner[2]; 144 unsigned long long iacc[1]; 145 146 union { 147 unsigned long tbr; 148 unsigned long gr[64]; 149 }; 150 }; 151 152 struct user_fpmedia_regs 153 { 154 unsigned long fr[64]; 155 unsigned long fner[2]; 156 unsigned long msr[2]; 157 unsigned long acc[8]; 158 unsigned char accg[8]; 159 unsigned long fsr[1]; 160 }; 161 162 struct user_context 163 { 164 struct user_int_regs i; 165 struct user_fpmedia_regs f; 166 167 void *extension; 168 } __attribute__((aligned(8))); */ 169 170 static LONGEST 171 frv_linux_sigcontext_reg_addr (struct frame_info *this_frame, int regno, 172 CORE_ADDR *sc_addr_cache_ptr) 173 { 174 struct gdbarch *gdbarch = get_frame_arch (this_frame); 175 enum bfd_endian byte_order = gdbarch_byte_order (gdbarch); 176 CORE_ADDR sc_addr; 177 178 if (sc_addr_cache_ptr && *sc_addr_cache_ptr) 179 { 180 sc_addr = *sc_addr_cache_ptr; 181 } 182 else 183 { 184 CORE_ADDR pc, sp; 185 gdb_byte buf[4]; 186 int tramp_type; 187 188 pc = get_frame_pc (this_frame); 189 tramp_type = frv_linux_pc_in_sigtramp (gdbarch, pc, 0); 190 191 get_frame_register (this_frame, sp_regnum, buf); 192 sp = extract_unsigned_integer (buf, sizeof buf, byte_order); 193 194 if (tramp_type == NORMAL_SIGTRAMP) 195 { 196 /* For a normal sigtramp frame, the sigcontext struct starts 197 at SP + 8. */ 198 sc_addr = sp + 8; 199 } 200 else if (tramp_type == RT_SIGTRAMP) 201 { 202 /* For a realtime sigtramp frame, SP + 12 contains a pointer 203 to a ucontext struct. The ucontext struct contains a 204 sigcontext struct starting 24 bytes in. (The offset of 205 uc_mcontext within struct ucontext is derived as follows: 206 stack_t is a 12-byte struct and struct sigcontext is 207 8-byte aligned. This gives an offset of 8 + 12 + 4 (for 208 padding) = 24.) */ 209 if (target_read_memory (sp + 12, buf, sizeof buf) != 0) 210 { 211 warning (_("Can't read realtime sigtramp frame.")); 212 return 0; 213 } 214 sc_addr = extract_unsigned_integer (buf, sizeof buf, byte_order); 215 sc_addr += 24; 216 } 217 else 218 internal_error (__FILE__, __LINE__, _("not a signal trampoline")); 219 220 if (sc_addr_cache_ptr) 221 *sc_addr_cache_ptr = sc_addr; 222 } 223 224 switch (regno) 225 { 226 case psr_regnum : 227 return sc_addr + 0; 228 /* sc_addr + 4 has "isr", the Integer Status Register. */ 229 case ccr_regnum : 230 return sc_addr + 8; 231 case cccr_regnum : 232 return sc_addr + 12; 233 case lr_regnum : 234 return sc_addr + 16; 235 case lcr_regnum : 236 return sc_addr + 20; 237 case pc_regnum : 238 return sc_addr + 24; 239 /* sc_addr + 28 is __status, the exception status. 240 sc_addr + 32 is syscallno, the syscall number or -1. 241 sc_addr + 36 is orig_gr8, the original syscall arg #1. 242 sc_addr + 40 is gner[0]. 243 sc_addr + 44 is gner[1]. */ 244 case iacc0h_regnum : 245 return sc_addr + 48; 246 case iacc0l_regnum : 247 return sc_addr + 52; 248 default : 249 if (first_gpr_regnum <= regno && regno <= last_gpr_regnum) 250 return sc_addr + 56 + 4 * (regno - first_gpr_regnum); 251 else if (first_fpr_regnum <= regno && regno <= last_fpr_regnum) 252 return sc_addr + 312 + 4 * (regno - first_fpr_regnum); 253 else 254 return -1; /* not saved. */ 255 } 256 } 257 258 /* Signal trampolines. */ 259 260 static struct trad_frame_cache * 261 frv_linux_sigtramp_frame_cache (struct frame_info *this_frame, 262 void **this_cache) 263 { 264 struct gdbarch *gdbarch = get_frame_arch (this_frame); 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 (struct trad_frame_cache *) *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; 417 418 /* gr0 always contains 0. Also, the kernel passes the TBR value in 419 this slot. */ 420 regcache->raw_supply_zeroed (first_gpr_regnum); 421 422 /* Fill gr32, ..., gr63 with zeros. */ 423 for (regi = first_gpr_regnum + 32; regi <= last_gpr_regnum; regi++) 424 regcache->raw_supply_zeroed (regi); 425 426 regcache_supply_regset (regset, regcache, regnum, gregs, len); 427 } 428 429 /* FRV Linux kernel register sets. */ 430 431 static const struct regset frv_linux_gregset = 432 { 433 frv_linux_gregmap, 434 frv_linux_supply_gregset, regcache_collect_regset 435 }; 436 437 static const struct regset frv_linux_fpregset = 438 { 439 frv_linux_fpregmap, 440 regcache_supply_regset, regcache_collect_regset 441 }; 442 443 static void 444 frv_linux_iterate_over_regset_sections (struct gdbarch *gdbarch, 445 iterate_over_regset_sections_cb *cb, 446 void *cb_data, 447 const struct regcache *regcache) 448 { 449 cb (".reg", sizeof (frv_elf_gregset_t), sizeof (frv_elf_gregset_t), 450 &frv_linux_gregset, NULL, cb_data); 451 cb (".reg2", sizeof (frv_elf_fpregset_t), sizeof (frv_elf_fpregset_t), 452 &frv_linux_fpregset, NULL, cb_data); 453 } 454 455 456 static void 457 frv_linux_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch) 458 { 459 linux_init_abi (info, gdbarch); 460 461 /* Set the sigtramp frame sniffer. */ 462 frame_unwind_append_unwinder (gdbarch, &frv_linux_sigtramp_frame_unwind); 463 464 set_gdbarch_iterate_over_regset_sections 465 (gdbarch, frv_linux_iterate_over_regset_sections); 466 } 467 468 static enum gdb_osabi 469 frv_linux_elf_osabi_sniffer (bfd *abfd) 470 { 471 int elf_flags; 472 473 elf_flags = elf_elfheader (abfd)->e_flags; 474 475 /* Assume GNU/Linux if using the FDPIC ABI. If/when another OS shows 476 up that uses this ABI, we'll need to start using .note sections 477 or some such. */ 478 if (elf_flags & EF_FRV_FDPIC) 479 return GDB_OSABI_LINUX; 480 else 481 return GDB_OSABI_UNKNOWN; 482 } 483 484 void _initialize_frv_linux_tdep (); 485 void 486 _initialize_frv_linux_tdep () 487 { 488 gdbarch_register_osabi (bfd_arch_frv, 0, GDB_OSABI_LINUX, 489 frv_linux_init_abi); 490 gdbarch_register_osabi_sniffer (bfd_arch_frv, 491 bfd_target_elf_flavour, 492 frv_linux_elf_osabi_sniffer); 493 } 494