gdb/i386bsd-nat.c

   1 /* Native-dependent code for modern i386 BSD's.
   2    Copyright 2000, 2001 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  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 #ifdef HAVE_SYS_PROCFS_H
  34 #include <sys/procfs.h>
  35 #endif
  36
  37 #ifndef HAVE_GREGSET_T
  38 typedef struct reg gregset_t;
  39 #endif
  40
  41 #ifndef HAVE_FPREGSET_T
  42 typedef struct fpreg fpregset_t;
  43 #endif
  44
  45 #include "gregset.h"
  46 \f
  47
  48 /* In older BSD versions we cannot get at some of the segment
  49    registers.  FreeBSD for example didn't support the %fs and %gs
  50    registers until the 3.0 release.  We have autoconf checks for their
  51    presence, and deal gracefully with their absence.  */
  52
  53 /* Registers we shouldn't try to fetch.  */
  54 #if !defined (CANNOT_FETCH_REGISTER)
  55 #define CANNOT_FETCH_REGISTER(regno) cannot_fetch_register (regno)
  56 #endif
  57
  58 /* Registers we shouldn't try to store.  */
  59 #if !defined (CANNOT_STORE_REGISTER)
  60 #define CANNOT_STORE_REGISTER(regno) cannot_fetch_register (regno)
  61 #endif
  62
  63 /* Offset to the gregset_t location where REG is stored.  */
  64 #define REG_OFFSET(reg) offsetof (gregset_t, reg)
  65
  66 /* At reg_offset[REGNO] you'll find the offset to the gregset_t
  67    location where the GDB register REGNO is stored.  Unsupported
  68    registers are marked with `-1'.  */
  69 static int reg_offset[] =
  70 {
  71   REG_OFFSET (r_eax),
  72   REG_OFFSET (r_ecx),
  73   REG_OFFSET (r_edx),
  74   REG_OFFSET (r_edx),
  75   REG_OFFSET (r_esp),
  76   REG_OFFSET (r_ebp),
  77   REG_OFFSET (r_esi),
  78   REG_OFFSET (r_edi),
  79   REG_OFFSET (r_eip),
  80   REG_OFFSET (r_eflags),
  81   REG_OFFSET (r_cs),
  82   REG_OFFSET (r_ss),
  83   REG_OFFSET (r_ds),
  84   REG_OFFSET (r_es),
  85 #ifdef HAVE_STRUCT_REG_R_FS
  86   REG_OFFSET (r_fs),
  87 #else
  88   -1,
  89 #endif
  90 #ifdef HAVE_STRUCT_REG_R_GS
  91   REG_OFFSET (r_gs)
  92 #else
  93   -1
  94 #endif
  95 };
  96
  97 #define REG_ADDR(regset, regno) ((char *) (regset) + reg_offset[regno])
  98
  99 /* Return nonzero if we shouldn't try to fetch register REGNO.  */
 100
 101 static int
 102 cannot_fetch_register (int regno)
 103 {
 104   return (reg_offset[regno] == -1);
 105 }
 106 \f
 107
 108 /* Transfering the registers between GDB, inferiors and core files.  */
 109
 110 /* Fill GDB's register array with the general-purpose register values
 111    in *GREGSETP.  */
 112
 113 void
 114 supply_gregset (gregset_t *gregsetp)
 115 {
 116   int i;
 117
 118   for (i = 0; i < NUM_GREGS; i++)
 119     {
 120       if (CANNOT_FETCH_REGISTER (i))
 121         supply_register (i, NULL);
 122       else
 123         supply_register (i, REG_ADDR (gregsetp, i));
 124     }
 125 }
 126
 127 /* Fill register REGNO (if it is a general-purpose register) in
 128    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 129    do this for all registers.  */
 130
 131 void
 132 fill_gregset (gregset_t *gregsetp, int regno)
 133 {
 134   int i;
 135
 136   for (i = 0; i < NUM_GREGS; i++)
 137     if ((regno == -1 || regno == i) && ! CANNOT_STORE_REGISTER (i))
 138       memcpy (REG_ADDR (gregsetp, i), &registers[REGISTER_BYTE (i)],
 139               REGISTER_RAW_SIZE (i));
 140 }
 141
 142 #include "i387-nat.h"
 143
 144 /* Fill GDB's register array with the floating-point register values
 145    in *FPREGSETP.  */
 146
 147 void
 148 supply_fpregset (fpregset_t *fpregsetp)
 149 {
 150   i387_supply_fsave ((char *) fpregsetp);
 151 }
 152
 153 /* Fill register REGNO (if it is a floating-point register) in
 154    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 155    do this for all registers.  */
 156
 157 void
 158 fill_fpregset (fpregset_t *fpregsetp, int regno)
 159 {
 160   i387_fill_fsave ((char *) fpregsetp, regno);
 161 }
 162
 163 /* Fetch register REGNO from the inferior.  If REGNO is -1, do this
 164    for all registers (including the floating point registers).  */
 165
 166 void
 167 fetch_inferior_registers (int regno)
 168 {
 169   gregset_t gregs;
 170
 171   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 172               (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 173     perror_with_name ("Couldn't get registers");
 174
 175   supply_gregset (&gregs);
 176
 177   if (regno == -1 || regno >= FP0_REGNUM)
 178     {
 179       fpregset_t fpregs;
 180
 181       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 182                   (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 183         perror_with_name ("Couldn't get floating point status");
 184
 185       supply_fpregset (&fpregs);
 186     }
 187 }
 188
 189 /* Store register REGNO back into the inferior.  If REGNO is -1, do
 190    this for all registers (including the floating point registers).  */
 191
 192 void
 193 store_inferior_registers (int regno)
 194 {
 195   gregset_t gregs;
 196
 197   if (ptrace (PT_GETREGS, PIDGET (inferior_ptid),
 198               (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 199     perror_with_name ("Couldn't get registers");
 200
 201   fill_gregset (&gregs, regno);
 202
 203   if (ptrace (PT_SETREGS, PIDGET (inferior_ptid),
 204               (PTRACE_ARG3_TYPE) &gregs, 0) == -1)
 205     perror_with_name ("Couldn't write registers");
 206
 207   if (regno == -1 || regno >= FP0_REGNUM)
 208     {
 209       fpregset_t fpregs;
 210
 211       if (ptrace (PT_GETFPREGS, PIDGET (inferior_ptid),
 212                   (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 213         perror_with_name ("Couldn't get floating point status");
 214
 215       fill_fpregset (&fpregs, regno);
 216
 217       if (ptrace (PT_SETFPREGS, PIDGET (inferior_ptid),
 218                   (PTRACE_ARG3_TYPE) &fpregs, 0) == -1)
 219         perror_with_name ("Couldn't write floating point status");
 220     }
 221 }
 222 \f
 223
 224 /* Support for debug registers.  */
 225
 226 #ifdef HAVE_PT_GETDBREGS
 227
 228 /* Not all versions of FreeBSD/i386 that support the debug registers
 229    have this macro.  */
 230 #ifndef DBREG_DRX
 231 #define DBREG_DRX(d, x) ((&d->dr0)[x])
 232 #endif
 233
 234 static void
 235 i386bsd_dr_set (int regnum, unsigned int value)
 236 {
 237   struct dbreg dbregs;
 238
 239   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 240               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 241     perror_with_name ("Couldn't get debug registers");
 242
 243   /* For some mysterious reason, some of the reserved bits in the
 244      debug control register get set.  Mask these off, otherwise the
 245      ptrace call below will fail.  */
 246   dbregs.dr7 &= ~(0x0000fc00);
 247
 248   DBREG_DRX ((&dbregs), regnum) = value;
 249
 250   if (ptrace (PT_SETDBREGS, PIDGET (inferior_ptid),
 251               (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
 252     perror_with_name ("Couldn't write debug registers");
 253 }
 254
 255 void
 256 i386bsd_dr_set_control (unsigned long control)
 257 {
 258   i386bsd_dr_set (7, control);
 259 }
 260
 261 void
 262 i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
 263 {
 264   gdb_assert (regnum >= 0 && regnum <= 4);
 265
 266   i386bsd_dr_set (regnum, addr);
 267 }
 268
 269 void
 270 i386bsd_dr_reset_addr (int regnum)
 271 {
 272   gdb_assert (regnum >= 0 && regnum <= 4);
 273
 274   i386bsd_dr_set (regnum, 0);
 275 }
 276
 277 unsigned long
 278 i386bsd_dr_get_status (void)
 279 {
 280   struct dbreg dbregs;
 281
 282   /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
 283      ptrace call fails breaks debugging remote targets.  The correct
 284      way to fix this is to add the hardware breakpoint and watchpoint
 285      stuff to the target vector.  For now, just return zero if the
 286      ptrace call fails.  */
 287   if (ptrace (PT_GETDBREGS, PIDGET (inferior_ptid),
 288               (PTRACE_ARG3_TYPE) & dbregs, 0) == -1)
 289 #if 0
 290     perror_with_name ("Couldn't read debug registers");
 291 #else
 292     return 0;
 293 #endif
 294
 295   return dbregs.dr6;
 296 }
 297
 298 #endif /* PT_GETDBREGS */
 299 \f
 300
 301 /* Support for the user struct.  */
 302
 303 /* Return the address register REGNO.  BLOCKEND is the value of
 304    u.u_ar0, which should point to the registers.  */
 305
 306 CORE_ADDR
 307 register_u_addr (CORE_ADDR blockend, int regno)
 308 {
 309   return (CORE_ADDR) REG_ADDR (blockend, regno);
 310 }
 311
 312 #include <sys/param.h>
 313 #include <sys/user.h>
 314
 315 /* Return the size of the user struct.  */
 316
 317 int
 318 kernel_u_size (void)
 319 {
 320   return (sizeof (struct user));
 321 }
 322 \f
 323 /* See i386bsd-tdep.c.  */
 324 extern int i386bsd_sigcontext_pc_offset;
 325
 326 void
 327 _initialize_i386bsd_nat (void)
 328 {
 329   /* To support the recognition of signal handlers, i386bsd-tdep.c
 330      hardcodes some constants.  Inclusion of this file means that we
 331      are compiling a native debugger, which means that we can use the
 332      system header files and sysctl(3) to get at the relevant
 333      information.  */
 334
 335   /* Override the default value for the offset of the program counter
 336      in the sigcontext structure.  */
 337   i386bsd_sigcontext_pc_offset = offsetof (struct sigcontext, sc_pc);
 338 }