gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2    Copyright 1988, 1989, 1991, 1992, 1993, 1994, 1995, 1996, 1998, 1999,
   3    2000 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23
  24 #ifdef HAVE_PTRACE_H
  25 #include <ptrace.h>
  26 #else
  27 #ifdef HAVE_SYS_PTRACE_H
  28 #include <sys/ptrace.h>
  29 #endif
  30 #endif
  31
  32 #include "frame.h"
  33 #include "inferior.h"
  34 #include "language.h"
  35 #include "gdbcore.h"
  36
  37 #ifdef USG
  38 #include <sys/types.h>
  39 #endif
  40
  41 #include <sys/param.h>
  42 #include <sys/dir.h>
  43 #include <signal.h>
  44 #include <sys/user.h>
  45 #include <sys/ioctl.h>
  46 #include <fcntl.h>
  47
  48
  49 /* FIXME: The following used to be just "#include <sys/debugreg.h>", but
  50  * the the Linux 2.1.x kernel and glibc 2.0.x are not in sync; including
  51  * <sys/debugreg.h> will result in an error.  With luck, these losers
  52  * will get their act together and we can trash this hack in the near future.
  53  * --jsm 1998-10-21
  54  */
  55
  56 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  57 #ifdef HAVE_ASM_DEBUGREG_H
  58 #include <asm/debugreg.h>
  59 #else
  60 #include <sys/debugreg.h>
  61 #endif
  62 #endif
  63
  64 #include <sys/file.h>
  65 #include "gdb_stat.h"
  66
  67 #ifdef HAVE_SYS_REG_H
  68 #include <sys/reg.h>
  69 #endif
  70
  71 #include "floatformat.h"
  72
  73 #include "target.h"
  74 \f
  75
  76 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
  77 /* symbols like 'EAX' come from <sys/reg.h> */
  78 static int regmap[] =
  79 {
  80   EAX, ECX, EDX, EBX,
  81   UESP, EBP, ESI, EDI,
  82   EIP, EFL, CS, SS,
  83   DS, ES, FS, GS,
  84 };
  85
  86 /* blockend is the value of u.u_ar0, and points to the
  87  * place where GS is stored
  88  */
  89
  90 int
  91 i386_register_u_addr (int blockend, int regnum)
  92 {
  93   struct user u;
  94   int fpstate;
  95   int ubase;
  96
  97   ubase = blockend;
  98   /* FIXME:  Should have better way to test floating point range */
  99   if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))
 100     {
 101 #ifdef KSTKSZ                   /* SCO, and others? */
 102       ubase += 4 * (SS + 1) - KSTKSZ;
 103       fpstate = ubase + ((char *) &u.u_fps.u_fpstate - (char *) &u);
 104       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
 105 #else
 106       fpstate = ubase + ((char *) &u.i387.st_space - (char *) &u);
 107       return (fpstate + 10 * (regnum - FP0_REGNUM));
 108 #endif
 109     }
 110   else
 111     {
 112       return (ubase + 4 * regmap[regnum]);
 113     }
 114
 115 }
 116 \f
 117 int
 118 kernel_u_size (void)
 119 {
 120   return (sizeof (struct user));
 121 }
 122 \f
 123 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 124
 125 #if !defined (offsetof)
 126 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 127 #endif
 128
 129 /* Record the value of the debug control register.  */
 130 static int debug_control_mirror;
 131
 132 /* Record which address associates with which register.  */
 133 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 134
 135 static int
 136 i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 137
 138 static int
 139 i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 140
 141 /* Insert a watchpoint.  */
 142
 143 int
 144 i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw)
 145 {
 146   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 147 }
 148
 149 static int
 150 i386_insert_aligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 151                                 int len, int rw)
 152 {
 153   int i;
 154   int read_write_bits, len_bits;
 155   int free_debug_register;
 156   int register_number;
 157
 158   /* Look for a free debug register.  */
 159   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 160     {
 161       if (address_lookup[i - DR_FIRSTADDR] == 0)
 162         break;
 163     }
 164
 165   /* No more debug registers!  */
 166   if (i > DR_LASTADDR)
 167     return -1;
 168
 169   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 170
 171   if (len == 1)
 172     len_bits = DR_LEN_1;
 173   else if (len == 2)
 174     {
 175       if (addr % 2)
 176         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 177       len_bits = DR_LEN_2;
 178     }
 179
 180   else if (len == 4)
 181     {
 182       if (addr % 4)
 183         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 184       len_bits = DR_LEN_4;
 185     }
 186   else
 187     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 188
 189   free_debug_register = i;
 190   register_number = free_debug_register - DR_FIRSTADDR;
 191   debug_control_mirror |=
 192     ((read_write_bits | len_bits)
 193      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 194   debug_control_mirror |=
 195     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 196   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 197   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 198
 199   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 200           debug_control_mirror);
 201   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 202           addr);
 203
 204   /* Record where we came from.  */
 205   address_lookup[register_number] = addr;
 206   return 0;
 207 }
 208
 209 static int
 210 i386_insert_nonaligned_watchpoint (int pid, CORE_ADDR waddr, CORE_ADDR addr,
 211                                    int len, int rw)
 212 {
 213   int align;
 214   int size;
 215   int rv;
 216
 217   static int size_try_array[4][4] =
 218   {
 219     { 1, 1, 1, 1 },             /* trying size one */
 220     { 2, 1, 2, 1 },             /* trying size two */
 221     { 2, 1, 2, 1 },             /* trying size three */
 222     { 4, 1, 2, 1 }              /* trying size four */
 223   };
 224
 225   rv = 0;
 226   while (len > 0)
 227     {
 228       align = addr % 4;
 229       /* Four is the maximum length for 386.  */
 230       size = size_try_array[len > 4 ? 3 : len - 1][align];
 231
 232       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 233       if (rv)
 234         {
 235           i386_remove_watchpoint (pid, waddr, size);
 236           return rv;
 237         }
 238       addr += size;
 239       len -= size;
 240     }
 241   return rv;
 242 }
 243
 244 /* Remove a watchpoint.  */
 245
 246 int
 247 i386_remove_watchpoint (int pid, CORE_ADDR addr, int len)
 248 {
 249   int i;
 250   int register_number;
 251
 252   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 253     {
 254       register_number = i - DR_FIRSTADDR;
 255       if (address_lookup[register_number] == addr)
 256         {
 257           debug_control_mirror &=
 258             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 259           address_lookup[register_number] = 0;
 260         }
 261     }
 262   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 263           debug_control_mirror);
 264   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 265
 266   return 0;
 267 }
 268
 269 /* Check if stopped by a watchpoint.  */
 270
 271 CORE_ADDR
 272 i386_stopped_by_watchpoint (int pid)
 273 {
 274   int i;
 275   int status;
 276
 277   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 278   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 279
 280   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 281     {
 282       if (status & (1 << (i - DR_FIRSTADDR)))
 283         return address_lookup[i - DR_FIRSTADDR];
 284     }
 285
 286   return 0;
 287 }
 288
 289 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */