1 /* Native-dependent code for modern i386 BSD's. 2 3 Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010, 4 2011 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 "inferior.h" 23 #include "regcache.h" 24 25 #include "gdb_assert.h" 26 #include <signal.h> 27 #include <stddef.h> 28 #include <sys/types.h> 29 #include <sys/ptrace.h> 30 #include <machine/reg.h> 31 #include <machine/frame.h> 32 33 #include "i386-tdep.h" 34 #include "i387-tdep.h" 35 #include "i386bsd-nat.h" 36 #include "inf-ptrace.h" 37 38 39 /* In older BSD versions we cannot get at some of the segment 40 registers. FreeBSD for example didn't support the %fs and %gs 41 registers until the 3.0 release. We have autoconf checks for their 42 presence, and deal gracefully with their absence. */ 43 44 /* Offset in `struct reg' where MEMBER is stored. */ 45 #define REG_OFFSET(member) offsetof (struct reg, member) 46 47 /* At i386bsd_reg_offset[REGNUM] you'll find the offset in `struct 48 reg' where the GDB register REGNUM is stored. Unsupported 49 registers are marked with `-1'. */ 50 static int i386bsd_r_reg_offset[] = 51 { 52 REG_OFFSET (r_eax), 53 REG_OFFSET (r_ecx), 54 REG_OFFSET (r_edx), 55 REG_OFFSET (r_ebx), 56 REG_OFFSET (r_esp), 57 REG_OFFSET (r_ebp), 58 REG_OFFSET (r_esi), 59 REG_OFFSET (r_edi), 60 REG_OFFSET (r_eip), 61 REG_OFFSET (r_eflags), 62 REG_OFFSET (r_cs), 63 REG_OFFSET (r_ss), 64 REG_OFFSET (r_ds), 65 REG_OFFSET (r_es), 66 #ifdef HAVE_STRUCT_REG_R_FS 67 REG_OFFSET (r_fs), 68 #else 69 -1, 70 #endif 71 #ifdef HAVE_STRUCT_REG_R_GS 72 REG_OFFSET (r_gs) 73 #else 74 -1 75 #endif 76 }; 77 78 /* Macro to determine if a register is fetched with PT_GETREGS. */ 79 #define GETREGS_SUPPLIES(regnum) \ 80 ((0 <= (regnum) && (regnum) <= 15)) 81 82 #ifdef HAVE_PT_GETXMMREGS 83 /* Set to 1 if the kernel supports PT_GETXMMREGS. Initialized to -1 84 so that we try PT_GETXMMREGS the first time around. */ 85 static int have_ptrace_xmmregs = -1; 86 #endif 87 88 89 /* Supply the general-purpose registers in GREGS, to REGCACHE. */ 90 91 static void 92 i386bsd_supply_gregset (struct regcache *regcache, const void *gregs) 93 { 94 const char *regs = gregs; 95 int regnum; 96 97 for (regnum = 0; regnum < ARRAY_SIZE (i386bsd_r_reg_offset); regnum++) 98 { 99 int offset = i386bsd_r_reg_offset[regnum]; 100 101 if (offset != -1) 102 regcache_raw_supply (regcache, regnum, regs + offset); 103 } 104 } 105 106 /* Collect register REGNUM from REGCACHE and store its contents in 107 GREGS. If REGNUM is -1, collect and store all appropriate 108 registers. */ 109 110 static void 111 i386bsd_collect_gregset (const struct regcache *regcache, 112 void *gregs, int regnum) 113 { 114 char *regs = gregs; 115 int i; 116 117 for (i = 0; i < ARRAY_SIZE (i386bsd_r_reg_offset); i++) 118 { 119 if (regnum == -1 || regnum == i) 120 { 121 int offset = i386bsd_r_reg_offset[i]; 122 123 if (offset != -1) 124 regcache_raw_collect (regcache, i, regs + offset); 125 } 126 } 127 } 128 129 /* Fetch register REGNUM from the inferior. If REGNUM is -1, do this 130 for all registers (including the floating point registers). */ 131 132 static void 133 i386bsd_fetch_inferior_registers (struct target_ops *ops, 134 struct regcache *regcache, int regnum) 135 { 136 if (regnum == -1 || GETREGS_SUPPLIES (regnum)) 137 { 138 struct reg regs; 139 140 if (ptrace (PT_GETREGS, PIDGET (inferior_ptid), 141 (PTRACE_TYPE_ARG3) ®s, 0) == -1) 142 perror_with_name (_("Couldn't get registers")); 143 144 i386bsd_supply_gregset (regcache, ®s); 145 if (regnum != -1) 146 return; 147 } 148 149 if (regnum == -1 || regnum >= I386_ST0_REGNUM) 150 { 151 struct fpreg fpregs; 152 #ifdef HAVE_PT_GETXMMREGS 153 char xmmregs[512]; 154 155 if (have_ptrace_xmmregs != 0 156 && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid), 157 (PTRACE_TYPE_ARG3) xmmregs, 0) == 0) 158 { 159 have_ptrace_xmmregs = 1; 160 i387_supply_fxsave (regcache, -1, xmmregs); 161 } 162 else 163 { 164 if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid), 165 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1) 166 perror_with_name (_("Couldn't get floating point status")); 167 168 i387_supply_fsave (regcache, -1, &fpregs); 169 } 170 #else 171 if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid), 172 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1) 173 perror_with_name (_("Couldn't get floating point status")); 174 175 i387_supply_fsave (regcache, -1, &fpregs); 176 #endif 177 } 178 } 179 180 /* Store register REGNUM back into the inferior. If REGNUM is -1, do 181 this for all registers (including the floating point registers). */ 182 183 static void 184 i386bsd_store_inferior_registers (struct target_ops *ops, 185 struct regcache *regcache, int regnum) 186 { 187 if (regnum == -1 || GETREGS_SUPPLIES (regnum)) 188 { 189 struct reg regs; 190 191 if (ptrace (PT_GETREGS, PIDGET (inferior_ptid), 192 (PTRACE_TYPE_ARG3) ®s, 0) == -1) 193 perror_with_name (_("Couldn't get registers")); 194 195 i386bsd_collect_gregset (regcache, ®s, regnum); 196 197 if (ptrace (PT_SETREGS, PIDGET (inferior_ptid), 198 (PTRACE_TYPE_ARG3) ®s, 0) == -1) 199 perror_with_name (_("Couldn't write registers")); 200 201 if (regnum != -1) 202 return; 203 } 204 205 if (regnum == -1 || regnum >= I386_ST0_REGNUM) 206 { 207 struct fpreg fpregs; 208 #ifdef HAVE_PT_GETXMMREGS 209 char xmmregs[512]; 210 211 if (have_ptrace_xmmregs != 0 212 && ptrace(PT_GETXMMREGS, PIDGET (inferior_ptid), 213 (PTRACE_TYPE_ARG3) xmmregs, 0) == 0) 214 { 215 have_ptrace_xmmregs = 1; 216 217 i387_collect_fxsave (regcache, regnum, xmmregs); 218 219 if (ptrace (PT_SETXMMREGS, PIDGET (inferior_ptid), 220 (PTRACE_TYPE_ARG3) xmmregs, 0) == -1) 221 perror_with_name (_("Couldn't write XMM registers")); 222 } 223 else 224 { 225 have_ptrace_xmmregs = 0; 226 #endif 227 if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid), 228 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1) 229 perror_with_name (_("Couldn't get floating point status")); 230 231 i387_collect_fsave (regcache, regnum, &fpregs); 232 233 if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid), 234 (PTRACE_TYPE_ARG3) &fpregs, 0) == -1) 235 perror_with_name (_("Couldn't write floating point status")); 236 #ifdef HAVE_PT_GETXMMREGS 237 } 238 #endif 239 } 240 } 241 242 /* Create a prototype *BSD/i386 target. The client can override it 243 with local methods. */ 244 245 struct target_ops * 246 i386bsd_target (void) 247 { 248 struct target_ops *t; 249 250 t = inf_ptrace_target (); 251 t->to_fetch_registers = i386bsd_fetch_inferior_registers; 252 t->to_store_registers = i386bsd_store_inferior_registers; 253 return t; 254 } 255 256 257 /* Support for debug registers. */ 258 259 #ifdef HAVE_PT_GETDBREGS 260 261 /* Not all versions of FreeBSD/i386 that support the debug registers 262 have this macro. */ 263 #ifndef DBREG_DRX 264 #define DBREG_DRX(d, x) ((&d->dr0)[x]) 265 #endif 266 267 static void 268 i386bsd_dr_set (int regnum, unsigned int value) 269 { 270 struct dbreg dbregs; 271 272 if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid), 273 (PTRACE_TYPE_ARG3) &dbregs, 0) == -1) 274 perror_with_name (_("Couldn't get debug registers")); 275 276 /* For some mysterious reason, some of the reserved bits in the 277 debug control register get set. Mask these off, otherwise the 278 ptrace call below will fail. */ 279 DBREG_DRX ((&dbregs), 7) &= ~(0x0000fc00); 280 281 DBREG_DRX ((&dbregs), regnum) = value; 282 283 if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid), 284 (PTRACE_TYPE_ARG3) &dbregs, 0) == -1) 285 perror_with_name (_("Couldn't write debug registers")); 286 } 287 288 void 289 i386bsd_dr_set_control (unsigned long control) 290 { 291 i386bsd_dr_set (7, control); 292 } 293 294 void 295 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr) 296 { 297 gdb_assert (regnum >= 0 && regnum <= 4); 298 299 i386bsd_dr_set (regnum, addr); 300 } 301 302 void 303 i386bsd_dr_reset_addr (int regnum) 304 { 305 gdb_assert (regnum >= 0 && regnum <= 4); 306 307 i386bsd_dr_set (regnum, 0); 308 } 309 310 unsigned long 311 i386bsd_dr_get_status (void) 312 { 313 struct dbreg dbregs; 314 315 /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the 316 ptrace call fails breaks debugging remote targets. The correct 317 way to fix this is to add the hardware breakpoint and watchpoint 318 stuff to the target vector. For now, just return zero if the 319 ptrace call fails. */ 320 if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid), 321 (PTRACE_TYPE_ARG3) &dbregs, 0) == -1) 322 #if 0 323 perror_with_name (_("Couldn't read debug registers")); 324 #else 325 return 0; 326 #endif 327 328 return DBREG_DRX ((&dbregs), 6); 329 } 330 331 #endif /* PT_GETDBREGS */ 332 333 334 void 335 _initialize_i386bsd_nat (void) 336 { 337 int offset; 338 339 /* To support the recognition of signal handlers, i386bsd-tdep.c 340 hardcodes some constants. Inclusion of this file means that we 341 are compiling a native debugger, which means that we can use the 342 system header files and sysctl(3) to get at the relevant 343 information. */ 344 345 #if defined (__FreeBSD_version) && __FreeBSD_version >= 400011 346 #define SC_REG_OFFSET i386fbsd4_sc_reg_offset 347 #elif defined (__FreeBSD_version) && __FreeBSD_version >= 300005 348 #define SC_REG_OFFSET i386fbsd_sc_reg_offset 349 #elif defined (NetBSD) || defined (__NetBSD_Version__) 350 #define SC_REG_OFFSET i386nbsd_sc_reg_offset 351 #elif defined (OpenBSD) 352 #define SC_REG_OFFSET i386obsd_sc_reg_offset 353 #endif 354 355 #ifdef SC_REG_OFFSET 356 357 /* We only check the program counter, stack pointer and frame 358 pointer since these members of `struct sigcontext' are essential 359 for providing backtraces. More checks could be added, but would 360 involve adding configure checks for the appropriate structure 361 members, since older BSD's don't provide all of them. */ 362 363 #define SC_PC_OFFSET SC_REG_OFFSET[I386_EIP_REGNUM] 364 #define SC_SP_OFFSET SC_REG_OFFSET[I386_ESP_REGNUM] 365 #define SC_FP_OFFSET SC_REG_OFFSET[I386_EBP_REGNUM] 366 367 /* Override the default value for the offset of the program counter 368 in the sigcontext structure. */ 369 offset = offsetof (struct sigcontext, sc_pc); 370 371 if (SC_PC_OFFSET != offset) 372 { 373 warning (_("\ 374 offsetof (struct sigcontext, sc_pc) yields %d instead of %d.\n\ 375 Please report this to <bug-gdb@gnu.org>."), 376 offset, SC_PC_OFFSET); 377 } 378 379 SC_PC_OFFSET = offset; 380 381 /* Likewise for the stack pointer. */ 382 offset = offsetof (struct sigcontext, sc_sp); 383 384 if (SC_SP_OFFSET != offset) 385 { 386 warning (_("\ 387 offsetof (struct sigcontext, sc_sp) yields %d instead of %d.\n\ 388 Please report this to <bug-gdb@gnu.org>."), 389 offset, SC_SP_OFFSET); 390 } 391 392 SC_SP_OFFSET = offset; 393 394 /* And the frame pointer. */ 395 offset = offsetof (struct sigcontext, sc_fp); 396 397 if (SC_FP_OFFSET != offset) 398 { 399 warning (_("\ 400 offsetof (struct sigcontext, sc_fp) yields %d instead of %d.\n\ 401 Please report this to <bug-gdb@gnu.org>."), 402 offset, SC_FP_OFFSET); 403 } 404 405 SC_FP_OFFSET = offset; 406 407 #endif /* SC_REG_OFFSET */ 408 } 409