gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2    Copyright (C) 1988, 1989, 1991, 1992, 1994, 1996 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, Boston, MA 02111-1307, USA.  */
  19
  20 #include "defs.h"
  21 #include "frame.h"
  22 #include "inferior.h"
  23 #include "language.h"
  24 #include "gdbcore.h"
  25
  26 #ifdef USG
  27 #include <sys/types.h>
  28 #endif
  29
  30 #include <sys/param.h>
  31 #include <sys/dir.h>
  32 #include <signal.h>
  33 #include <sys/user.h>
  34 #include <sys/ioctl.h>
  35 #include <fcntl.h>
  36
  37 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
  38 #include <sys/debugreg.h>
  39 #endif
  40
  41 #include <sys/file.h>
  42 #include "gdb_stat.h"
  43
  44 #ifndef NO_SYS_REG_H
  45 #include <sys/reg.h>
  46 #endif
  47
  48 #include "floatformat.h"
  49
  50 #include "target.h"
  51
  52 \f
  53 /* this table must line up with REGISTER_NAMES in tm-i386v.h */
  54 /* symbols like 'EAX' come from <sys/reg.h> */
  55 static int regmap[] =
  56 {
  57   EAX, ECX, EDX, EBX,
  58   UESP, EBP, ESI, EDI,
  59   EIP, EFL, CS, SS,
  60   DS, ES, FS, GS,
  61 };
  62
  63 /* blockend is the value of u.u_ar0, and points to the
  64  * place where GS is stored
  65  */
  66
  67 int
  68 i386_register_u_addr (blockend, regnum)
  69      int blockend;
  70      int regnum;
  71 {
  72   struct user u;
  73   int fpstate;
  74   int ubase;
  75
  76   ubase = blockend;
  77   /* FIXME:  Should have better way to test floating point range */
  78   if (regnum >= FP0_REGNUM && regnum <= (FP0_REGNUM + 7))
  79     {
  80 #ifdef KSTKSZ   /* SCO, and others? */
  81       ubase += 4 * (SS + 1) - KSTKSZ;
  82       fpstate = ubase + ((char *)&u.u_fps.u_fpstate - (char *)&u);
  83       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  84 #else
  85       fpstate = ubase + ((char *)&u.i387.st_space - (char *)&u);
  86       return (fpstate + 10 * (regnum - FP0_REGNUM));
  87 #endif
  88     }
  89   else
  90     {
  91       return (ubase + 4 * regmap[regnum]);
  92     }
  93
  94 }
  95 \f
  96 int
  97 kernel_u_size ()
  98 {
  99   return (sizeof (struct user));
 100 }
 101 \f
 102 #ifdef TARGET_HAS_HARDWARE_WATCHPOINTS
 103
 104 #if !defined (offsetof)
 105 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
 106 #endif
 107
 108 /* Record the value of the debug control register.  */
 109 static int debug_control_mirror;
 110
 111 /* Record which address associates with which register.  */
 112 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 113
 114 static int
 115 i386_insert_aligned_watchpoint PARAMS ((int, CORE_ADDR, CORE_ADDR, int,
 116                                            int));
 117
 118 static int
 119 i386_insert_nonaligned_watchpoint PARAMS ((int, CORE_ADDR, CORE_ADDR, int,
 120                                            int));
 121
 122 /* Insert a watchpoint.  */
 123
 124 int
 125 i386_insert_watchpoint (pid, addr, len, rw)
 126      int pid;
 127      CORE_ADDR addr;
 128      int len;
 129      int rw;
 130 {
 131   return i386_insert_aligned_watchpoint (pid, addr, addr, len, rw);
 132 }
 133
 134 static int
 135 i386_insert_aligned_watchpoint (pid, waddr, addr, len, rw)
 136      int pid;
 137      CORE_ADDR waddr;
 138      CORE_ADDR addr;
 139      int len;
 140      int rw;
 141 {
 142   int i;
 143   int read_write_bits, len_bits;
 144   int free_debug_register;
 145   int register_number;
 146
 147   /* Look for a free debug register.  */
 148   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 149     {
 150       if (address_lookup[i - DR_FIRSTADDR] == 0)
 151         break;
 152     }
 153
 154   /* No more debug registers!  */
 155   if (i > DR_LASTADDR)
 156     return -1;
 157
 158   read_write_bits = (rw & 1) ? DR_RW_READ : DR_RW_WRITE;
 159
 160   if (len == 1)
 161     len_bits = DR_LEN_1;
 162   else if (len == 2)
 163     {
 164       if (addr % 2)
 165         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 166       len_bits = DR_LEN_2;
 167     }
 168
 169   else if (len == 4)
 170     {
 171       if (addr % 4)
 172         return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 173       len_bits = DR_LEN_4;
 174     }
 175   else
 176     return i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw);
 177
 178   free_debug_register = i;
 179   register_number = free_debug_register - DR_FIRSTADDR;
 180   debug_control_mirror |=
 181     ((read_write_bits | len_bits)
 182      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 183   debug_control_mirror |=
 184     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 185   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 186   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 187
 188   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 189           debug_control_mirror);
 190   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 191           addr);
 192
 193   /* Record where we came from.  */
 194   address_lookup[register_number] = addr;
 195   return 0;
 196 }
 197
 198 static int
 199 i386_insert_nonaligned_watchpoint (pid, waddr, addr, len, rw)
 200      int pid;
 201      CORE_ADDR waddr;
 202      CORE_ADDR addr;
 203      int len;
 204      int rw;
 205 {
 206   int align;
 207   int size;
 208   int rv;
 209
 210   static int size_try_array[16] = {
 211     1, 1, 1, 1,                 /* trying size one */
 212     2, 1, 2, 1,                 /* trying size two */
 213     2, 1, 2, 1,                 /* trying size three */
 214     4, 1, 2, 1                  /* trying size four */
 215   };
 216
 217   rv = 0;
 218   while (len > 0)
 219     {
 220       align = addr % 4;
 221       /* Four is the maximum length for 386.  */
 222       size = (len > 4) ? 3 : len - 1;
 223       size = size_try_array[size * 4 + align];
 224
 225       rv = i386_insert_aligned_watchpoint (pid, waddr, addr, size, rw);
 226       if (rv)
 227         {
 228           i386_remove_watchpoint (pid, waddr, size);
 229           return rv;
 230         }
 231       addr += size;
 232       len -= size;
 233     }
 234   return rv;
 235 }
 236
 237 /* Remove a watchpoint.  */
 238
 239 int
 240 i386_remove_watchpoint (pid, addr, len)
 241      int pid;
 242      CORE_ADDR addr;
 243      int len;
 244 {
 245   int i;
 246   int register_number;
 247
 248   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 249     {
 250       register_number = i - DR_FIRSTADDR;
 251       if (address_lookup[register_number] == addr)
 252         {
 253           debug_control_mirror &=
 254             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 255           address_lookup[register_number] = 0;
 256         }
 257     }
 258   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 259           debug_control_mirror);
 260   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 261
 262   return 0;
 263 }
 264
 265 /* Check if stopped by a watchpoint.  */
 266
 267 CORE_ADDR
 268 i386_stopped_by_watchpoint (pid)
 269     int pid;
 270 {
 271   int i;
 272   int status;
 273
 274   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 275   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 276
 277   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 278     {
 279       if (status & (1 << (i - DR_FIRSTADDR)))
 280         return address_lookup[i - DR_FIRSTADDR];
 281     }
 282
 283   return 0;
 284 }
 285
 286 #endif /* TARGET_HAS_HARDWARE_WATCHPOINTS */
 287
 288 #if 0
 289 /* using FLOAT_INFO as is would be a problem.  FLOAT_INFO is called
 290    via a command xxx and eventually calls ptrace without ever having
 291    traversed the target vector.  This would be terribly impolite
 292    behaviour for a sun4 hosted remote gdb.
 293
 294    A fix might be to move this code into the "info registers" command.
 295    rich@cygnus.com 15 Sept 92. */
 296 i386_float_info ()
 297 {
 298   struct user u; /* just for address computations */
 299   int i;
 300   /* fpstate defined in <sys/user.h> */
 301   struct fpstate *fpstatep;
 302   char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
 303   unsigned int uaddr;
 304   char fpvalid = 0;
 305   unsigned int rounded_addr;
 306   unsigned int rounded_size;
 307   extern int corechan;
 308   int skip;
 309
 310   uaddr = (char *)&u.u_fpvalid - (char *)&u;
 311   if (target_has_execution)
 312     {
 313       unsigned int data;
 314       unsigned int mask;
 315
 316       rounded_addr = uaddr & -sizeof (int);
 317       data = ptrace (3, inferior_pid, (PTRACE_ARG3_TYPE) rounded_addr, 0);
 318       mask = 0xff << ((uaddr - rounded_addr) * 8);
 319
 320       fpvalid = ((data & mask) != 0);
 321     }
 322 #if 0
 323   else
 324     {
 325       if (lseek (corechan, uaddr, 0) < 0)
 326         perror ("seek on core file");
 327       if (myread (corechan, &fpvalid, 1) < 0)
 328         perror ("read on core file");
 329
 330     }
 331 #endif  /* no core support yet */
 332
 333   if (fpvalid == 0)
 334     {
 335       printf_unfiltered ("no floating point status saved\n");
 336       return;
 337     }
 338
 339   uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
 340   if (target_has_execution)
 341     {
 342       int *ip;
 343
 344       rounded_addr = uaddr & -sizeof (int);
 345       rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
 346                       sizeof (int) - 1) / sizeof (int);
 347       skip = uaddr - rounded_addr;
 348
 349       ip = (int *)buf;
 350       for (i = 0; i < rounded_size; i++)
 351         {
 352           *ip++ = ptrace (3, inferior_pid, (PTRACE_ARG3_TYPE) rounded_addr, 0);
 353           rounded_addr += sizeof (int);
 354         }
 355     }
 356 #if 0
 357   else
 358     {
 359       if (lseek (corechan, uaddr, 0) < 0)
 360         perror_with_name ("seek on core file");
 361       if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
 362         perror_with_name ("read from core file");
 363       skip = 0;
 364     }
 365 #endif  /* 0 */
 366
 367   fpstatep = (struct fpstate *)(buf + skip);
 368   print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
 369 }
 370
 371 #endif /* never */