gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2    Copyright (C) 1988, 89, 91, 92, 94, 96, 1998 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 2 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, write to the Free Software
  18    Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include "defs.h"
  22
  23 #ifdef HAVE_PTRACE_H
  24 #include <ptrace.h>
  25 #else
  26 #ifdef HAVE_SYS_PTRACE_H
  27 #include <sys/ptrace.h>
  28 #endif
  29 #endif
  30
  31 #include "frame.h"
  32 #include "inferior.h"
  33 #include "language.h"
  34 #include "gdbcore.h"
  35
  36 #ifdef USG
  37 #include <sys/types.h>
  38 #endif
  39
  40 #include <sys/param.h>
  41 #include <sys/dir.h>
  42 #include <signal.h>
  43 #include <sys/user.h>
  44 #include <sys/ioctl.h>
  45 #include <fcntl.h>
  46
  47
  48 /* FIXME: The following used to be just "#include <sys/debugreg.h>", but
  49  * the the Linux 2.1.x kernel and glibc 2.0.x are not in sync; including
  50  * <sys/debugreg.h> will result in an error.  With luck, these losers
  51  * will get their act together and we can trash this hack in the near future.
  52  * --jsm 1998-10-21
  53  */
  54
  55 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  56 #ifdef HAVE_ASM_DEBUGREG_H
  57 #include <asm/debugreg.h>
  58 #else
  59 #include <sys/debugreg.h>
  60 #endif
  61 #endif
  62
  63 #include <sys/file.h>
  64 #include "gdb_stat.h"
  65
  66 #ifdef HAVE_SYS_REG_H
  67 #include <sys/reg.h>
  68 #endif
  69
  70 #include "floatformat.h"
  71
  72 #include "target.h"
  73 \f
  74
  75 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
  76 /* symbols like 'EAX' come from <sys/reg.h> */
  77 static int regmap[] =
  78 {
  79   EAX, ECX, EDX, EBX,
  80   UESP, EBP, ESI, EDI,
  81   EIP, EFL, CS, SS,
  82   DS, ES, FS, GS,
  83 };
  84
  85 /* blockend is the value of u.u_ar0, and points to the
  86  * place where GS is stored
  87  */
  88
  89 int
  90 i386_register_u_addr (blockend, regnum)
  91      int blockend;
  92      int regnum;
  93 {
  94   struct user u;
  95   int fpstate;
  96   int ubase;
  97
  98   ubase = blockend;
  99   /* FIXME:  Should have better way to test floating point range */
 100   if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))
 101     {
 102 #ifdef KSTKSZ                   /* SCO, and others? */
 103       ubase += 4 * (SS + 1) - KSTKSZ;
 104       fpstate = ubase + ((char *) &u.u_fps.u_fpstate - (char *) &u);
 105       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
 106 #else
 107       fpstate = ubase + ((char *) &u.i387.st_space - (char *) &u);
 108       return (fpstate + 10 * (regnum - FP0_REGNUM));
 109 #endif
 110     }
 111   else
 112     {
 113       return (ubase + 4 * regmap[regnum]);
 114     }
 115
 116 }
 117 \f
 118 int
 119 kernel_u_size ()
 120 {
 121   return (sizeof (struct user));
 122 }
 123 \f
 124 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 125
 126 #if !defined (offsetof)
 127 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 128 #endif
 129
 130 /* Record the value of the debug control register.  */
 131 static int debug_control_mirror;
 132
 133 /* Record which address associates with which register.  */
 134 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 135
 136 static int
 137 i386_insert_aligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 138
 139 static int
 140 i386_insert_nonaligned_watchpoint (int, CORE_ADDR, CORE_ADDR, int, int);
 141
 142 /* Insert a watchpoint.  */
 143
 144 int
 145 i386_insert_watchpoint (pid, addr, len, rw)
 146      int pid;
 147      CORE_ADDR addr;
 148      int len;
 149      int rw;
 150 {
 151   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 152 }
 153
 154 static int
 155 i386_insert_aligned_watchpoint (pid, waddr, addr, len, rw)
 156      int pid;
 157      CORE_ADDR waddr;
 158      CORE_ADDR addr;
 159      int len;
 160      int rw;
 161 {
 162   int i;
 163   int read_write_bits, len_bits;
 164   int free_debug_register;
 165   int register_number;
 166
 167   /* Look for a free debug register.  */
 168   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 169     {
 170       if (address_lookup[i - DR_FIRSTADDR] == 0)
 171         break;
 172     }
 173
 174   /* No more debug registers!  */
 175   if (i > DR_LASTADDR)
 176     return -1;
 177
 178   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 179
 180   if (len == 1)
 181     len_bits = DR_LEN_1;
 182   else if (len == 2)
 183     {
 184       if (addr % 2)
 185         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 186       len_bits = DR_LEN_2;
 187     }
 188
 189   else if (len == 4)
 190     {
 191       if (addr % 4)
 192         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 193       len_bits = DR_LEN_4;
 194     }
 195   else
 196     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 197
 198   free_debug_register = i;
 199   register_number = free_debug_register - DR_FIRSTADDR;
 200   debug_control_mirror |=
 201     ((read_write_bits | len_bits)
 202      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 203   debug_control_mirror |=
 204     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 205   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 206   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 207
 208   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 209           debug_control_mirror);
 210   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 211           addr);
 212
 213   /* Record where we came from.  */
 214   address_lookup[register_number] = addr;
 215   return 0;
 216 }
 217
 218 static int
 219 i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw)
 220      int pid;
 221      CORE_ADDR waddr;
 222      CORE_ADDR addr;
 223      int len;
 224      int rw;
 225 {
 226   int align;
 227   int size;
 228   int rv;
 229
 230   static int size_try_array[4][4] =
 231   {
 232     { 1, 1, 1, 1 },             /* trying size one */
 233     { 2, 1, 2, 1 },             /* trying size two */
 234     { 2, 1, 2, 1 },             /* trying size three */
 235     { 4, 1, 2, 1 }              /* trying size four */
 236   };
 237
 238   rv = 0;
 239   while (len > 0)
 240     {
 241       align = addr % 4;
 242       /* Four is the maximum length for 386.  */
 243       size = size_try_array[len > 4 ? 3 : len - 1][align];
 244
 245       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 246       if (rv)
 247         {
 248           i386_remove_watchpoint (pid, waddr, size);
 249           return rv;
 250         }
 251       addr += size;
 252       len -= size;
 253     }
 254   return rv;
 255 }
 256
 257 /* Remove a watchpoint.  */
 258
 259 int
 260 i386_remove_watchpoint (pid, addr, len)
 261      int pid;
 262      CORE_ADDR addr;
 263      int len;
 264 {
 265   int i;
 266   int register_number;
 267
 268   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 269     {
 270       register_number = i - DR_FIRSTADDR;
 271       if (address_lookup[register_number] == addr)
 272         {
 273           debug_control_mirror &=
 274             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 275           address_lookup[register_number] = 0;
 276         }
 277     }
 278   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 279           debug_control_mirror);
 280   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 281
 282   return 0;
 283 }
 284
 285 /* Check if stopped by a watchpoint.  */
 286
 287 CORE_ADDR
 288 i386_stopped_by_watchpoint (pid)
 289      int pid;
 290 {
 291   int i;
 292   int status;
 293
 294   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 295   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 296
 297   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 298     {
 299       if (status & (1 << (i - DR_FIRSTADDR)))
 300         return address_lookup[i - DR_FIRSTADDR];
 301     }
 302
 303   return 0;
 304 }
 305
 306 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */