gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2
   3    Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1998,
   4    1999, 2000, 2002 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 2 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, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24
  25 #ifdef HAVE_PTRACE_H
  26 #include <ptrace.h>
  27 #else
  28 #ifdef HAVE_SYS_PTRACE_H
  29 #include <sys/ptrace.h>
  30 #endif
  31 #endif
  32
  33 #include "frame.h"
  34 #include "inferior.h"
  35 #include "language.h"
  36 #include "gdbcore.h"
  37
  38 #ifdef USG
  39 #include <sys/types.h>
  40 #endif
  41
  42 #include <sys/param.h>
  43 #include <sys/dir.h>
  44 #include <signal.h>
  45 #include <sys/user.h>
  46 #include <sys/ioctl.h>
  47 #include <fcntl.h>
  48
  49 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  50 #include <sys/debugreg.h>
  51 #endif
  52
  53 #include <sys/file.h>
  54 #include "gdb_stat.h"
  55
  56 #ifdef HAVE_SYS_REG_H
  57 #include <sys/reg.h>
  58 #endif
  59
  60 #include "floatformat.h"
  61
  62 #include "target.h"
  63 \f
  64
  65 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
  66 /* symbols like 'EAX' come from <sys/reg.h> */
  67 static int regmap[] =
  68 {
  69   EAX, ECX, EDX, EBX,
  70   UESP, EBP, ESI, EDI,
  71   EIP, EFL, CS, SS,
  72   DS, ES, FS, GS,
  73 };
  74
  75 /* blockend is the value of u.u_ar0, and points to the
  76  * place where GS is stored
  77  */
  78
  79 int
  80 i386_register_u_addr (int blockend, int regnum)
  81 {
  82   struct user u;
  83   int fpstate;
  84   int ubase;
  85
  86   ubase = blockend;
  87   /* FIXME:  Should have better way to test floating point range */
  88   if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))
  89     {
  90 #ifdef KSTKSZ                   /* SCO, and others? */
  91       ubase += 4 * (SS + 1) - KSTKSZ;
  92       fpstate = ubase + ((char *) &u.u_fps.u_fpstate - (char *) &u);
  93       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  94 #else
  95       fpstate = ubase + ((char *) &u.i387.st_space - (char *) &u);
  96       return (fpstate + 10 * (regnum - FP0_REGNUM));
  97 #endif
  98     }
  99   else
 100     {
 101       return (ubase + 4 * regmap[regnum]);
 102     }
 103
 104 }
 105 \f
 106 int
 107 kernel_u_size (void)
 108 {
 109   return (sizeof (struct user));
 110 }
 111 \f
 112 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 113
 114 #if !defined (offsetof)
 115 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 116 #endif
 117
 118 /* Record the value of the debug control register.  */
 119 static int debug_control_mirror;
 120
 121 /* Record which address associates with which register.  */
 122 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 123
 124 static int
 125 i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 126
 127 static int
 128 i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 129
 130 /* Insert a watchpoint.  */
 131
 132 int
 133 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)
 134 {
 135   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 136 }
 137
 138 static int
 139 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 140                                 int len, int rw)
 141 {
 142   int i;
 143   int read_write_bits, len_bits;
 144   int free_debug_register;
 145   int register_number;
 146
 147   /* Look for a free debug register.  */
 148   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 149     {
 150       if (address_lookup[i - DR_FIRSTADDR] == 0)
 151         break;
 152     }
 153
 154   /* No more debug registers!  */
 155   if (i > DR_LASTADDR)
 156     return -1;
 157
 158   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 159
 160   if (len == 1)
 161     len_bits = DR_LEN_1;
 162   else if (len == 2)
 163     {
 164       if (addr % 2)
 165         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 166       len_bits = DR_LEN_2;
 167     }
 168
 169   else if (len == 4)
 170     {
 171       if (addr % 4)
 172         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 173       len_bits = DR_LEN_4;
 174     }
 175   else
 176     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 177
 178   free_debug_register = i;
 179   register_number = free_debug_register - DR_FIRSTADDR;
 180   debug_control_mirror |=
 181     ((read_write_bits | len_bits)
 182      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 183   debug_control_mirror |=
 184     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 185   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 186   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 187
 188   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 189           debug_control_mirror);
 190   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 191           addr);
 192
 193   /* Record where we came from.  */
 194   address_lookup[register_number] = addr;
 195   return 0;
 196 }
 197
 198 static int
 199 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 200                                    int len, int rw)
 201 {
 202   int align;
 203   int size;
 204   int rv;
 205
 206   static int size_try_array[4][4] =
 207   {
 208     { 1, 1, 1, 1 },             /* trying size one */
 209     { 2, 1, 2, 1 },             /* trying size two */
 210     { 2, 1, 2, 1 },             /* trying size three */
 211     { 4, 1, 2, 1 }              /* trying size four */
 212   };
 213
 214   rv = 0;
 215   while (len > 0)
 216     {
 217       align = addr % 4;
 218       /* Four is the maximum length for 386.  */
 219       size = size_try_array[len > 4 ? 3 : len - 1][align];
 220
 221       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 222       if (rv)
 223         {
 224           i386_remove_watchpoint (pid, waddr, size);
 225           return rv;
 226         }
 227       addr += size;
 228       len -= size;
 229     }
 230   return rv;
 231 }
 232
 233 /* Remove a watchpoint.  */
 234
 235 int
 236 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)
 237 {
 238   int i;
 239   int register_number;
 240
 241   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 242     {
 243       register_number = i - DR_FIRSTADDR;
 244       if (address_lookup[register_number] == addr)
 245         {
 246           debug_control_mirror &=
 247             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 248           address_lookup[register_number] = 0;
 249         }
 250     }
 251   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 252           debug_control_mirror);
 253   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 254
 255   return 0;
 256 }
 257
 258 /* Check if stopped by a watchpoint.  */
 259
 260 CORE_ADDR
 261 i386_stopped_by_watchpoint (int pid)
 262 {
 263   int i;
 264   int status;
 265
 266   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 267   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 268
 269   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 270     {
 271       if (status & (1 << (i - DR_FIRSTADDR)))
 272         return address_lookup[i - DR_FIRSTADDR];
 273     }
 274
 275   return 0;
 276 }
 277
 278 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */