gdb/i386v-nat.c

   1 /* Intel 386 native support for System V systems (pre-SVR4).
   2
   3    Copyright (C) 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999,
   4    2000, 2002, 2007 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., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, 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 #include <sys/param.h>
  39 #include <sys/dir.h>
  40 #include <signal.h>
  41 #include <sys/user.h>
  42 #include <sys/ioctl.h>
  43 #include <fcntl.h>
  44
  45 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  46 #include <sys/debugreg.h>
  47 #endif
  48
  49 #include <sys/file.h>
  50 #include "gdb_stat.h"
  51
  52 #ifdef HAVE_SYS_REG_H
  53 #include <sys/reg.h>
  54 #endif
  55
  56 #include "floatformat.h"
  57
  58 #include "target.h"
  59
  60 #include "i386-tdep.h"
  61 \f
  62
  63 /* Mapping between the general-purpose registers in `struct user'
  64    format and GDB's register array layout.  */
  65 static int regmap[] =
  66 {
  67   EAX, ECX, EDX, EBX,
  68   UESP, EBP, ESI, EDI,
  69   EIP, EFL, CS, SS,
  70   DS, ES, FS, GS,
  71 };
  72
  73 /* Support for the user struct.  */
  74
  75 /* Return the address of register REGNUM.  BLOCKEND is the value of
  76    u.u_ar0, and points to the place where GS is stored.  */
  77
  78 CORE_ADDR
  79 register_u_addr (CORE_ADDR blockend, int regnum)
  80 {
  81   struct user u;
  82   CORE_ADDR fpstate;
  83
  84   if (i386_fp_regnum_p (regnum))
  85     {
  86 #ifdef KSTKSZ                   /* SCO, and others?  */
  87       blockend += 4 * (SS + 1) - KSTKSZ;
  88       fpstate = blockend + ((char *) &u.u_fps.u_fpstate - (char *) &u);
  89       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  90 #else
  91       fpstate = blockend + ((char *) &u.i387.st_space - (char *) &u);
  92       return (fpstate + 10 * (regnum - FP0_REGNUM));
  93 #endif
  94     }
  95
  96   return (blockend + 4 * regmap[regnum]);
  97 }
  98
  99 /* Return the size of the user struct.  */
 100
 101 int
 102 kernel_u_size (void)
 103 {
 104   return (sizeof (struct user));
 105 }
 106 \f
 107 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 108
 109 #if !defined (offsetof)
 110 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 111 #endif
 112
 113 /* Record the value of the debug control register.  */
 114 static int debug_control_mirror;
 115
 116 /* Record which address associates with which register.  */
 117 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 118
 119 static int i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int,
 120                                            int);
 121
 122 static int i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int,
 123                                               int);
 124
 125 /* Insert a watchpoint.  */
 126
 127 int
 128 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)
 129 {
 130   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 131 }
 132
 133 static int
 134 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 135                                 int len, int rw)
 136 {
 137   int i;
 138   int read_write_bits, len_bits;
 139   int free_debug_register;
 140   int register_number;
 141
 142   /* Look for a free debug register.  */
 143   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 144     {
 145       if (address_lookup[i - DR_FIRSTADDR] == 0)
 146         break;
 147     }
 148
 149   /* No more debug registers!  */
 150   if (i > DR_LASTADDR)
 151     return -1;
 152
 153   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 154
 155   if (len == 1)
 156     len_bits = DR_LEN_1;
 157   else if (len == 2)
 158     {
 159       if (addr % 2)
 160         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 161       len_bits = DR_LEN_2;
 162     }
 163
 164   else if (len == 4)
 165     {
 166       if (addr % 4)
 167         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 168       len_bits = DR_LEN_4;
 169     }
 170   else
 171     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 172
 173   free_debug_register = i;
 174   register_number = free_debug_register - DR_FIRSTADDR;
 175   debug_control_mirror |=
 176     ((read_write_bits | len_bits)
 177      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 178   debug_control_mirror |=
 179     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 180   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 181   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 182
 183   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 184           debug_control_mirror);
 185   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 186           addr);
 187
 188   /* Record where we came from.  */
 189   address_lookup[register_number] = addr;
 190   return 0;
 191 }
 192
 193 static int
 194 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 195                                    int len, int rw)
 196 {
 197   int align;
 198   int size;
 199   int rv;
 200
 201   static int size_try_array[4][4] =
 202   {
 203     { 1, 1, 1, 1 },             /* trying size one */
 204     { 2, 1, 2, 1 },             /* trying size two */
 205     { 2, 1, 2, 1 },             /* trying size three */
 206     { 4, 1, 2, 1 }              /* trying size four */
 207   };
 208
 209   rv = 0;
 210   while (len > 0)
 211     {
 212       align = addr % 4;
 213       /* Four is the maximum length for 386.  */
 214       size = size_try_array[len > 4 ? 3 : len - 1][align];
 215
 216       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 217       if (rv)
 218         {
 219           i386_remove_watchpoint (pid, waddr, size);
 220           return rv;
 221         }
 222       addr += size;
 223       len -= size;
 224     }
 225   return rv;
 226 }
 227
 228 /* Remove a watchpoint.  */
 229
 230 int
 231 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)
 232 {
 233   int i;
 234   int register_number;
 235
 236   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 237     {
 238       register_number = i - DR_FIRSTADDR;
 239       if (address_lookup[register_number] == addr)
 240         {
 241           debug_control_mirror &=
 242             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 243           address_lookup[register_number] = 0;
 244         }
 245     }
 246   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 247           debug_control_mirror);
 248   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 249
 250   return 0;
 251 }
 252
 253 /* Check if stopped by a watchpoint.  */
 254
 255 CORE_ADDR
 256 i386_stopped_by_watchpoint (int pid)
 257 {
 258   int i;
 259   int status;
 260
 261   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 262   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 263
 264   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 265     {
 266       if (status & (1 << (i - DR_FIRSTADDR)))
 267         return address_lookup[i - DR_FIRSTADDR];
 268     }
 269
 270   return 0;
 271 }
 272
 273 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */