gdb/i386v-nat.c

   1 /* Intel 386 native support for System V 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 /* Mapping between the general-purpose registers in `struct user'
  66    format and GDB's register array layout.  */
  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 /* Support for the user struct.  */
  76
  77 /* Return the address of register REGNUM.  BLOCKEND is the value of
  78    u.u_ar0, and points to the place where GS is stored.  */
  79
  80 CORE_ADDR
  81 register_u_addr (CORE_ADDR blockend, int regnum)
  82 {
  83   struct user u;
  84   CORE_ADDR fpstate;
  85
  86   if (FP_REGNUM_P (regnum))
  87     {
  88 #ifdef KSTKSZ                   /* SCO, and others?  */
  89       blockend += 4 * (SS + 1) - KSTKSZ;
  90       fpstate = blockend + ((char *) &u.u_fps.u_fpstate - (char *) &u);
  91       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  92 #else
  93       fpstate = blockend + ((char *) &u.i387.st_space - (char *) &u);
  94       return (fpstate + 10 * (regnum - FP0_REGNUM));
  95 #endif
  96     }
  97
  98   return (blockend + 4 * regmap[regnum]);
  99 }
 100
 101 /* Return the size of the user struct.  */
 102
 103 int
 104 kernel_u_size (void)
 105 {
 106   return (sizeof (struct user));
 107 }
 108 \f
 109 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 110
 111 #if !defined (offsetof)
 112 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 113 #endif
 114
 115 /* Record the value of the debug control register.  */
 116 static int debug_control_mirror;
 117
 118 /* Record which address associates with which register.  */
 119 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 120
 121 static int
 122 i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 123
 124 static int
 125 i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 126
 127 /* Insert a watchpoint.  */
 128
 129 int
 130 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)
 131 {
 132   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 133 }
 134
 135 static int
 136 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 137                                 int len, int rw)
 138 {
 139   int i;
 140   int read_write_bits, len_bits;
 141   int free_debug_register;
 142   int register_number;
 143
 144   /* Look for a free debug register.  */
 145   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 146     {
 147       if (address_lookup[i - DR_FIRSTADDR] == 0)
 148         break;
 149     }
 150
 151   /* No more debug registers!  */
 152   if (i > DR_LASTADDR)
 153     return -1;
 154
 155   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 156
 157   if (len == 1)
 158     len_bits = DR_LEN_1;
 159   else if (len == 2)
 160     {
 161       if (addr % 2)
 162         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 163       len_bits = DR_LEN_2;
 164     }
 165
 166   else if (len == 4)
 167     {
 168       if (addr % 4)
 169         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 170       len_bits = DR_LEN_4;
 171     }
 172   else
 173     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 174
 175   free_debug_register = i;
 176   register_number = free_debug_register - DR_FIRSTADDR;
 177   debug_control_mirror |=
 178     ((read_write_bits | len_bits)
 179      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 180   debug_control_mirror |=
 181     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 182   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 183   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 184
 185   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 186           debug_control_mirror);
 187   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 188           addr);
 189
 190   /* Record where we came from.  */
 191   address_lookup[register_number] = addr;
 192   return 0;
 193 }
 194
 195 static int
 196 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 197                                    int len, int rw)
 198 {
 199   int align;
 200   int size;
 201   int rv;
 202
 203   static int size_try_array[4][4] =
 204   {
 205     { 1, 1, 1, 1 },             /* trying size one */
 206     { 2, 1, 2, 1 },             /* trying size two */
 207     { 2, 1, 2, 1 },             /* trying size three */
 208     { 4, 1, 2, 1 }              /* trying size four */
 209   };
 210
 211   rv = 0;
 212   while (len > 0)
 213     {
 214       align = addr % 4;
 215       /* Four is the maximum length for 386.  */
 216       size = size_try_array[len > 4 ? 3 : len - 1][align];
 217
 218       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 219       if (rv)
 220         {
 221           i386_remove_watchpoint (pid, waddr, size);
 222           return rv;
 223         }
 224       addr += size;
 225       len -= size;
 226     }
 227   return rv;
 228 }
 229
 230 /* Remove a watchpoint.  */
 231
 232 int
 233 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)
 234 {
 235   int i;
 236   int register_number;
 237
 238   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 239     {
 240       register_number = i - DR_FIRSTADDR;
 241       if (address_lookup[register_number] == addr)
 242         {
 243           debug_control_mirror &=
 244             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 245           address_lookup[register_number] = 0;
 246         }
 247     }
 248   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 249           debug_control_mirror);
 250   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 251
 252   return 0;
 253 }
 254
 255 /* Check if stopped by a watchpoint.  */
 256
 257 CORE_ADDR
 258 i386_stopped_by_watchpoint (int pid)
 259 {
 260   int i;
 261   int status;
 262
 263   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 264   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 265
 266   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 267     {
 268       if (status & (1 << (i - DR_FIRSTADDR)))
 269         return address_lookup[i - DR_FIRSTADDR];
 270     }
 271
 272   return 0;
 273 }
 274
 275 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */