gdb/i386v-nat.c

   1 /* Intel 386 native support for SYSV systems (pre-SVR4).
   2    Copyright (C) 1988, 1989, 1991, 1992, 1994 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., 675 Mass Ave, Cambridge, MA 02139, 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_CAN_USE_HARDWARE_WATCHPOINT
  38 #include <sys/debugreg.h>
  39 #endif
  40
  41 #include <sys/file.h>
  42 #include <sys/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 #if 0
  73   /* this will be needed if fp registers are reinstated */
  74   /* for now, you can look at them with 'info float'
  75    * sys5 wont let you change them with ptrace anyway
  76    */
  77   if (regnum >= FP0_REGNUM && regnum <= FP7_REGNUM)
  78     {
  79       int ubase, fpstate;
  80       struct user u;
  81       ubase = blockend + 4 * (SS + 1) - KSTKSZ;
  82       fpstate = ubase + ((char *)&u.u_fpstate - (char *)&u);
  83       return (fpstate + 0x1c + 10 * (regnum - FP0_REGNUM));
  84     }
  85   else
  86 #endif
  87     return (blockend + 4 * regmap[regnum]);
  88
  89 }
  90 \f
  91 #ifdef TARGET_CAN_USE_HARDWARE_WATCHPOINT
  92
  93 #if !defined (offsetof)
  94 #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
  95 #endif
  96
  97 /* Record the value of the debug control register.  */
  98 static int debug_control_mirror;
  99
 100 /* Record which address associates with which register.  */
 101 static CORE_ADDR address_lookup[DR_LASTADDR - DR_FIRSTADDR + 1];
 102
 103 static int
 104 i386_insert_nonaligned_watchpoint PARAMS ((int, CORE_ADDR, int, int));
 105
 106 /* Insert a watchpoint.  */
 107
 108 int
 109 i386_insert_watchpoint (pid, addr, len, rw)
 110      int pid;
 111      CORE_ADDR addr;
 112      int len;
 113      int rw;
 114 {
 115   int i;
 116   int read_write_bits, len_bits;
 117   int free_debug_register;
 118   int register_number;
 119
 120   /* Look for a free debug register.  */
 121   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 122     {
 123       if (address_lookup[i - DR_FIRSTADDR] == 0)
 124         break;
 125     }
 126
 127   /* No more debug registers!  */
 128   if (i > DR_LASTADDR)
 129     return -1;
 130
 131   read_write_bits = ((rw & 1) ? DR_RW_READ : 0) | ((rw & 2) ? DR_RW_WRITE : 0);
 132
 133   if (len == 1)
 134     len_bits = DR_LEN_1;
 135   else if (len == 2)
 136     {
 137       if (addr % 2)
 138         return i386_insert_nonaligned_watchpoint (pid, addr, len, rw);
 139       len_bits = DR_LEN_2;
 140     }
 141
 142   else if (len == 4)
 143     {
 144       if (addr % 4)
 145         return i386_insert_nonaligned_watchpoint (pid, addr, len, rw);
 146       len_bits = DR_LEN_4;
 147     }
 148   else
 149     return i386_insert_nonaligned_watchpoint (pid, addr, len, rw);
 150
 151   free_debug_register = i;
 152   register_number = free_debug_register - DR_FIRSTADDR;
 153   debug_control_mirror |=
 154     ((read_write_bits | len_bits)
 155      << (DR_CONTROL_SHIFT + DR_CONTROL_SIZE * register_number));
 156   debug_control_mirror |=
 157     (1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 158   debug_control_mirror |= DR_LOCAL_SLOWDOWN;
 159   debug_control_mirror &= ~DR_CONTROL_RESERVED;
 160
 161   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 162           debug_control_mirror);
 163   ptrace (6, pid, offsetof (struct user, u_debugreg[free_debug_register]),
 164           addr);
 165
 166   /* Record where we came from.  */
 167   address_lookup[register_number] = addr;
 168   return 0;
 169 }
 170
 171 static int
 172 i386_insert_nonaligned_watchpoint (pid, addr, len, rw)
 173      int                pid;
 174      CORE_ADDR          addr;
 175      int                len;
 176      int                rw;
 177 {
 178   int align;
 179   int size;
 180   int rv;
 181
 182   static int size_try_array[16] = {
 183     1, 1, 1, 1,                 /* trying size one */
 184     2, 1, 2, 1,                 /* trying size two */
 185     2, 1, 2, 1,                 /* trying size three */
 186     4, 1, 2, 1                  /* trying size four */
 187   };
 188
 189   rv = 0;
 190   while (len > 0)
 191     {
 192       align = addr % 4;
 193       /* Four is the maximum length for 386.  */
 194       size = (len > 4) ? 3 : len - 1;
 195       size = size_try_array[size * 4 + align];
 196
 197       rv = i386_insert_watchpoint (pid, addr, size, rw);
 198       if (rv)
 199         {
 200           i386_remove_watchpoint (pid, addr, size);
 201           return rv;
 202         }
 203       addr += size;
 204       len -= size;
 205     }
 206   return rv;
 207 }
 208
 209 /* Remove a watchpoint.  */
 210
 211 int
 212 i386_remove_watchpoint (pid, addr, len)
 213      int pid;
 214      CORE_ADDR addr;
 215      int len;
 216 {
 217   int i;
 218   int register_number;
 219
 220   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 221     {
 222       register_number = i - DR_FIRSTADDR;
 223       if (address_lookup[register_number] == addr)
 224         {
 225           debug_control_mirror &=
 226             ~(1 << (DR_LOCAL_ENABLE_SHIFT + DR_ENABLE_SIZE * register_number));
 227           address_lookup[register_number] = 0;
 228         }
 229     }
 230   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_CONTROL]),
 231           debug_control_mirror);
 232   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 233
 234   return 0;
 235 }
 236
 237 /* Check if stopped by a watchpoint.  */
 238
 239 CORE_ADDR
 240 i386_stopped_by_watchpoint (pid)
 241     int pid;
 242 {
 243   int i;
 244   int status;
 245
 246   status = ptrace (3, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 247   ptrace (6, pid, offsetof (struct user, u_debugreg[DR_STATUS]), 0);
 248
 249   for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
 250     {
 251       if (status & (1 << (i - DR_FIRSTADDR)))
 252         return address_lookup[i - DR_FIRSTADDR];
 253     }
 254
 255   return 0;
 256 }
 257
 258 #endif /* TARGET_CAN_USE_HARDWARE_WATCHPOINT */
 259
 260 #if 0
 261 /* using FLOAT_INFO as is would be a problem.  FLOAT_INFO is called
 262    via a command xxx and eventually calls ptrace without ever having
 263    traversed the target vector.  This would be terribly impolite
 264    behaviour for a sun4 hosted remote gdb.
 265
 266    A fix might be to move this code into the "info registers" command.
 267    rich@cygnus.com 15 Sept 92. */
 268 i386_float_info ()
 269 {
 270   struct user u; /* just for address computations */
 271   int i;
 272   /* fpstate defined in <sys/user.h> */
 273   struct fpstate *fpstatep;
 274   char buf[sizeof (struct fpstate) + 2 * sizeof (int)];
 275   unsigned int uaddr;
 276   char fpvalid = 0;
 277   unsigned int rounded_addr;
 278   unsigned int rounded_size;
 279   extern int corechan;
 280   int skip;
 281
 282   uaddr = (char *)&u.u_fpvalid - (char *)&u;
 283   if (target_has_execution)
 284     {
 285       unsigned int data;
 286       unsigned int mask;
 287
 288       rounded_addr = uaddr & -sizeof (int);
 289       data = ptrace (3, inferior_pid, (PTRACE_ARG3_TYPE) rounded_addr, 0);
 290       mask = 0xff << ((uaddr - rounded_addr) * 8);
 291
 292       fpvalid = ((data & mask) != 0);
 293     }
 294 #if 0
 295   else
 296     {
 297       if (lseek (corechan, uaddr, 0) < 0)
 298         perror ("seek on core file");
 299       if (myread (corechan, &fpvalid, 1) < 0)
 300         perror ("read on core file");
 301
 302     }
 303 #endif  /* no core support yet */
 304
 305   if (fpvalid == 0)
 306     {
 307       printf_unfiltered ("no floating point status saved\n");
 308       return;
 309     }
 310
 311   uaddr = (char *)&U_FPSTATE(u) - (char *)&u;
 312   if (target_has_execution)
 313     {
 314       int *ip;
 315
 316       rounded_addr = uaddr & -sizeof (int);
 317       rounded_size = (((uaddr + sizeof (struct fpstate)) - uaddr) +
 318                       sizeof (int) - 1) / sizeof (int);
 319       skip = uaddr - rounded_addr;
 320
 321       ip = (int *)buf;
 322       for (i = 0; i < rounded_size; i++)
 323         {
 324           *ip++ = ptrace (3, inferior_pid, (PTRACE_ARG3_TYPE) rounded_addr, 0);
 325           rounded_addr += sizeof (int);
 326         }
 327     }
 328 #if 0
 329   else
 330     {
 331       if (lseek (corechan, uaddr, 0) < 0)
 332         perror_with_name ("seek on core file");
 333       if (myread (corechan, buf, sizeof (struct fpstate)) < 0)
 334         perror_with_name ("read from core file");
 335       skip = 0;
 336     }
 337 #endif  /* 0 */
 338
 339   fpstatep = (struct fpstate *)(buf + skip);
 340   print_387_status (fpstatep->status, (struct env387 *)fpstatep->state);
 341 }
 342
 343 #endif /* never */