gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2    Copyright (C) 1988, 89, 91, 92, 94, 96, 1998 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
  23 #ifdef HAVE_PTRACE_H
  24 #include <ptrace.h>
  25 #else
  26 #ifdef HAVE_SYS_PTRACE_H
  27 #include <sys/ptrace.h>
  28 #endif
  29 #endif
  30
  31 #include "frame.h"
  32 #include "inferior.h"
  33 #include "language.h"
  34 #include "gdbcore.h"
  35
  36 #ifdef USG
  37 #include <sys/types.h>
  38 #endif
  39
  40 #include <sys/param.h>
  41 #include <sys/dir.h>
  42 #include <signal.h>
  43 #include <sys/user.h>
  44 #include <sys/ioctl.h>
  45 #include <fcntl.h>
  46
  47
  48 /* FIXME: The following used to be just "#include <sys/debugreg.h>", but
  49  * the the Linux 2.1.x kernel and glibc 2.0.x are not in sync; including
  50  * <sys/debugreg.h> will result in an error.  With luck, these losers
  51  * will get their act together and we can trash this hack in the near future.
  52  * --jsm 1998-10-21
  53  */
  54
  55 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  56 #ifdef HAVE_ASM_DEBUGREG_H
  57 #include <asm/debugreg.h>
  58 #else
  59 #include <sys/debugreg.h>
  60 #endif
  61 #endif
  62
  63 #include <sys/file.h>
  64 #include "gdb_stat.h"
  65
  66 #ifdef HAVE_SYS_REG_H
  67 #include <sys/reg.h>
  68 #endif
  69
  70 #include "floatformat.h"
  71
  72 #include "target.h"
  73 \f
  74
  75 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
  76 /* symbols like 'EAX' come from <sys/reg.h> */
  77 static int regmap[] =
  78 {
  79   EAX, ECX, EDX, EBX,
  80   UESP, EBP, ESI, EDI,
  81   EIP, EFL, CS, SS,
  82   DS, ES, FS, GS,
  83 };
  84
  85 /* blockend is the value of u.u_ar0, and points to the
  86  * place where GS is stored
  87  */
  88
  89 int
  90 i386_register_u_addr (int blockend, int regnum)
  91 {
  92   struct user u;
  93   int fpstate;
  94   int ubase;
  95
  96   ubase = blockend;
  97   /* FIXME:  Should have better way to test floating point range */
  98   if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))
  99     {
 100 #ifdef KSTKSZ                   /* SCO, and others? */
 101       ubase += 4 * (SS + 1) - KSTKSZ;
 102       fpstate = ubase + ((char *) &u.u_fps.u_fpstate - (char *) &u);
 103       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
 104 #else
 105       fpstate = ubase + ((char *) &u.i387.st_space - (char *) &u);
 106       return (fpstate + 10 * (regnum - FP0_REGNUM));
 107 #endif
 108     }
 109   else
 110     {
 111       return (ubase + 4 * regmap[regnum]);
 112     }
 113
 114 }
 115 \f
 116 int
 117 kernel_u_size (void)
 118 {
 119   return (sizeof (struct user));
 120 }
 121 \f
 122 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 123
 124 #if !defined (offsetof)
 125 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 126 #endif
 127
 128 /* Record the value of the debug control register.  */
 129 static int debug_control_mirror;
 130
 131 /* Record which address associates with which register.  */
 132 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 133
 134 static int
 135 i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 136
 137 static int
 138 i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 139
 140 /* Insert a watchpoint.  */
 141
 142 int
 143 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)
 144 {
 145   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 146 }
 147
 148 static int
 149 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 150                                 int len, int rw)
 151 {
 152   int i;
 153   int read_write_bits, len_bits;
 154   int free_debug_register;
 155   int register_number;
 156
 157   /* Look for a free debug register.  */
 158   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 159     {
 160       if (address_lookup[i - DR_FIRSTADDR] == 0)
 161         break;
 162     }
 163
 164   /* No more debug registers!  */
 165   if (i > DR_LASTADDR)
 166     return -1;
 167
 168   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 169
 170   if (len == 1)
 171     len_bits = DR_LEN_1;
 172   else if (len == 2)
 173     {
 174       if (addr % 2)
 175         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 176       len_bits = DR_LEN_2;
 177     }
 178
 179   else if (len == 4)
 180     {
 181       if (addr % 4)
 182         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 183       len_bits = DR_LEN_4;
 184     }
 185   else
 186     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 187
 188   free_debug_register = i;
 189   register_number = free_debug_register - DR_FIRSTADDR;
 190   debug_control_mirror |=
 191     ((read_write_bits | len_bits)
 192      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 193   debug_control_mirror |=
 194     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 195   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 196   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 197
 198   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 199           debug_control_mirror);
 200   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 201           addr);
 202
 203   /* Record where we came from.  */
 204   address_lookup[register_number] = addr;
 205   return 0;
 206 }
 207
 208 static int
 209 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 210                                    int len, int rw)
 211 {
 212   int align;
 213   int size;
 214   int rv;
 215
 216   static int size_try_array[4][4] =
 217   {
 218     { 1, 1, 1, 1 },             /* trying size one */
 219     { 2, 1, 2, 1 },             /* trying size two */
 220     { 2, 1, 2, 1 },             /* trying size three */
 221     { 4, 1, 2, 1 }              /* trying size four */
 222   };
 223
 224   rv = 0;
 225   while (len > 0)
 226     {
 227       align = addr % 4;
 228       /* Four is the maximum length for 386.  */
 229       size = size_try_array[len > 4 ? 3 : len - 1][align];
 230
 231       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 232       if (rv)
 233         {
 234           i386_remove_watchpoint (pid, waddr, size);
 235           return rv;
 236         }
 237       addr += size;
 238       len -= size;
 239     }
 240   return rv;
 241 }
 242
 243 /* Remove a watchpoint.  */
 244
 245 int
 246 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)
 247 {
 248   int i;
 249   int register_number;
 250
 251   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 252     {
 253       register_number = i - DR_FIRSTADDR;
 254       if (address_lookup[register_number] == addr)
 255         {
 256           debug_control_mirror &=
 257             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 258           address_lookup[register_number] = 0;
 259         }
 260     }
 261   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 262           debug_control_mirror);
 263   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 264
 265   return 0;
 266 }
 267
 268 /* Check if stopped by a watchpoint.  */
 269
 270 CORE_ADDR
 271 i386_stopped_by_watchpoint (int pid)
 272 {
 273   int i;
 274   int status;
 275
 276   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 277   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 278
 279   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 280     {
 281       if (status & (1 << (i - DR_FIRSTADDR)))
 282         return address_lookup[i - DR_FIRSTADDR];
 283     }
 284
 285   return 0;
 286 }
 287
 288 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */