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
  64 #include "i386-tdep.h"
  65 \f
  66
  67 /* Mapping between the general-purpose registers in `struct user'
  68    format and GDB's register array layout.  */
  69 static int regmap[] =
  70 {
  71   EAX, ECX, EDX, EBX,
  72   UESP, EBP, ESI, EDI,
  73   EIP, EFL, CS, SS,
  74   DS, ES, FS, GS,
  75 };
  76
  77 /* Support for the user struct.  */
  78
  79 /* Return the address of register REGNUM.  BLOCKEND is the value of
  80    u.u_ar0, and points to the place where GS is stored.  */
  81
  82 CORE_ADDR
  83 register_u_addr (CORE_ADDR blockend, int regnum)
  84 {
  85   struct user u;
  86   CORE_ADDR fpstate;
  87
  88   if (i386_fp_regnum_p (regnum))
  89     {
  90 #ifdef KSTKSZ                   /* SCO, and others?  */
  91       blockend += 4 * (SS + 1) - KSTKSZ;
  92       fpstate = blockend + ((char *) &u.u_fps.u_fpstate - (char *) &u);
  93       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  94 #else
  95       fpstate = blockend + ((char *) &u.i387.st_space - (char *) &u);
  96       return (fpstate + 10 * (regnum - FP0_REGNUM));
  97 #endif
  98     }
  99
 100   return (blockend + 4 * regmap[regnum]);
 101 }
 102
 103 /* Return the size of the user struct.  */
 104
 105 int
 106 kernel_u_size (void)
 107 {
 108   return (sizeof (struct user));
 109 }
 110 \f
 111 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 112
 113 #if !defined (offsetof)
 114 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 115 #endif
 116
 117 /* Record the value of the debug control register.  */
 118 static int debug_control_mirror;
 119
 120 /* Record which address associates with which register.  */
 121 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 122
 123 static int i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int,
 124                                            int);
 125
 126 static int i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int,
 127                                               int);
 128
 129 /* Insert a watchpoint.  */
 130
 131 int
 132 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)
 133 {
 134   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 135 }
 136
 137 static int
 138 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 139                                 int len, int rw)
 140 {
 141   int i;
 142   int read_write_bits, len_bits;
 143   int free_debug_register;
 144   int register_number;
 145
 146   /* Look for a free debug register.  */
 147   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 148     {
 149       if (address_lookup[i - DR_FIRSTADDR] == 0)
 150         break;
 151     }
 152
 153   /* No more debug registers!  */
 154   if (i > DR_LASTADDR)
 155     return -1;
 156
 157   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 158
 159   if (len == 1)
 160     len_bits = DR_LEN_1;
 161   else if (len == 2)
 162     {
 163       if (addr % 2)
 164         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 165       len_bits = DR_LEN_2;
 166     }
 167
 168   else if (len == 4)
 169     {
 170       if (addr % 4)
 171         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 172       len_bits = DR_LEN_4;
 173     }
 174   else
 175     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 176
 177   free_debug_register = i;
 178   register_number = free_debug_register - DR_FIRSTADDR;
 179   debug_control_mirror |=
 180     ((read_write_bits | len_bits)
 181      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 182   debug_control_mirror |=
 183     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 184   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 185   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 186
 187   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 188           debug_control_mirror);
 189   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 190           addr);
 191
 192   /* Record where we came from.  */
 193   address_lookup[register_number] = addr;
 194   return 0;
 195 }
 196
 197 static int
 198 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 199                                    int len, int rw)
 200 {
 201   int align;
 202   int size;
 203   int rv;
 204
 205   static int size_try_array[4][4] =
 206   {
 207     { 1, 1, 1, 1 },             /* trying size one */
 208     { 2, 1, 2, 1 },             /* trying size two */
 209     { 2, 1, 2, 1 },             /* trying size three */
 210     { 4, 1, 2, 1 }              /* trying size four */
 211   };
 212
 213   rv = 0;
 214   while (len > 0)
 215     {
 216       align = addr % 4;
 217       /* Four is the maximum length for 386.  */
 218       size = size_try_array[len > 4 ? 3 : len - 1][align];
 219
 220       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 221       if (rv)
 222         {
 223           i386_remove_watchpoint (pid, waddr, size);
 224           return rv;
 225         }
 226       addr += size;
 227       len -= size;
 228     }
 229   return rv;
 230 }
 231
 232 /* Remove a watchpoint.  */
 233
 234 int
 235 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)
 236 {
 237   int i;
 238   int register_number;
 239
 240   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 241     {
 242       register_number = i - DR_FIRSTADDR;
 243       if (address_lookup[register_number] == addr)
 244         {
 245           debug_control_mirror &=
 246             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 247           address_lookup[register_number] = 0;
 248         }
 249     }
 250   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 251           debug_control_mirror);
 252   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 253
 254   return 0;
 255 }
 256
 257 /* Check if stopped by a watchpoint.  */
 258
 259 CORE_ADDR
 260 i386_stopped_by_watchpoint (int pid)
 261 {
 262   int i;
 263   int status;
 264
 265   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 266   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 267
 268   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 269     {
 270       if (status & (1 << (i - DR_FIRSTADDR)))
 271         return address_lookup[i - DR_FIRSTADDR];
 272     }
 273
 274   return 0;
 275 }
 276
 277 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */