gdb/pyr-xdep.c

   1 /* Low level Pyramid interface to ptrace, for GDB when running under Unix.
   2    Copyright (C) 1988, 1989, 1991 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
  24 #include <sys/param.h>
  25 #include <sys/dir.h>
  26 #include <signal.h>
  27 #include <sys/ioctl.h>
  28 /* #include <fcntl.h>  Can we live without this?  */
  29
  30 #include "gdbcore.h"
  31 #include <sys/user.h>           /* After a.out.h  */
  32 #include <sys/file.h>
  33 #include <sys/stat.h>
  34
  35 \f
  36 void
  37 fetch_inferior_registers (regno)
  38      int regno;
  39 {
  40   register int datum;
  41   register unsigned int regaddr;
  42   int reg_buf[NUM_REGS+1];
  43   struct user u;
  44   register int skipped_frames = 0;
  45
  46   registers_fetched ();
  47
  48   for (regno = 0; regno < 64; regno++) {
  49     reg_buf[regno] = ptrace (3, inferior_pid, regno, 0);
  50
  51 #if defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
  52     printf ("Fetching %s from inferior, got %0x\n",
  53             reg_names[regno],
  54             reg_buf[regno]);
  55 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
  56
  57     if (reg_buf[regno] == -1 && errno == EIO) {
  58       printf("fetch_interior_registers: fetching %s from inferior\n",
  59              reg_names[regno]);
  60       errno = 0;
  61     }
  62     supply_register (regno, reg_buf+regno);
  63   }
  64   /* that leaves regs 64, 65, and 66 */
  65   datum = ptrace (3, inferior_pid,
  66                   ((char *)&u.u_pcb.pcb_csp) -
  67                   ((char *)&u), 0);
  68
  69
  70
  71   /* FIXME: Find the Current Frame Pointer (CFP). CFP is a global
  72      register (ie, NOT windowed), that gets saved in a frame iff
  73      the code for that frame has a prologue (ie, "adsf N").  If
  74      there is a prologue, the adsf insn saves the old cfp in
  75      pr13, cfp is set to sp, and N bytes of locals are allocated
  76      (sp is decremented by n).
  77      This makes finding CFP hard. I guess the right way to do it
  78      is:
  79      - If this is the innermost frame, believe ptrace() or
  80      the core area.
  81      - Otherwise:
  82      Find the first insn of the current frame.
  83      - find the saved pc;
  84      - find the call insn that saved it;
  85      - figure out where the call is to;
  86      - if the first insn is an adsf, we got a frame
  87      pointer. */
  88
  89
  90   /* Normal processors have separate stack pointers for user and
  91      kernel mode. Getting the last user mode frame on such
  92      machines is easy: the kernel context of the ptrace()'d
  93      process is on the kernel stack, and the USP points to what
  94      we want. But Pyramids only have a single cfp for both user and
  95      kernel mode.  And processes being ptrace()'d have some
  96      kernel-context control frames on their stack.
  97      To avoid tracing back into the kernel context of an inferior,
  98      we skip 0 or more contiguous control frames where the pc is
  99      in the kernel. */
 100
 101   while (1) {
 102     register int inferior_saved_pc;
 103     inferior_saved_pc = ptrace (1, inferior_pid, datum+((32+15)*4), 0);
 104     if (inferior_saved_pc > 0) break;
 105 #if defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 106     printf("skipping kernel frame %08x, pc=%08x\n", datum,
 107            inferior_saved_pc);
 108 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 109     skipped_frames++;
 110     datum -= CONTROL_STACK_FRAME_SIZE;
 111   }
 112
 113   reg_buf[CSP_REGNUM] = datum;
 114   supply_register(CSP_REGNUM, reg_buf+CSP_REGNUM);
 115 #ifdef  PYRAMID_CONTROL_FRAME_DEBUGGING
 116   if (skipped_frames) {
 117     fprintf (stderr,
 118              "skipped %d frames from %x to %x; cfp was %x, now %x\n",
 119              skipped_frames, reg_buf[CSP_REGNUM]);
 120   }
 121 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 122 }
 123
 124 /* Store our register values back into the inferior.
 125    If REGNO is -1, do this for all registers.
 126    Otherwise, REGNO specifies which register (so we can save time).  */
 127
 128 void
 129 store_inferior_registers (regno)
 130      int regno;
 131 {
 132   register unsigned int regaddr;
 133   char buf[80];
 134
 135   if (regno >= 0)
 136     {
 137       if ((0 <= regno) && (regno < 64)) {
 138         /*regaddr = register_addr (regno, offset);*/
 139         regaddr = regno;
 140         errno = 0;
 141         ptrace (6, inferior_pid, regaddr, read_register (regno));
 142         if (errno != 0)
 143           {
 144             sprintf (buf, "writing register number %d", regno);
 145             perror_with_name (buf);
 146           }
 147       }
 148     }
 149   else
 150     {
 151       for (regno = 0; regno < NUM_REGS; regno++)
 152         {
 153           /*regaddr = register_addr (regno, offset);*/
 154           regaddr = regno;
 155           errno = 0;
 156           ptrace (6, inferior_pid, regaddr, read_register (regno));
 157           if (errno != 0)
 158             {
 159               sprintf (buf, "writing all regs, number %d", regno);
 160               perror_with_name (buf);
 161             }
 162         }
 163 }
 164 \f
 165 /*** Extensions to  core and dump files, for GDB. */
 166
 167 extern unsigned int last_frame_offset;
 168
 169 #ifdef PYRAMID_CORE
 170
 171 /* Can't make definitions here static, since core.c needs them
 172    to do bounds checking on the core-file areas. O well. */
 173
 174 /* have two stacks: one for data, one for register windows. */
 175 extern CORE_ADDR reg_stack_start;
 176 extern CORE_ADDR reg_stack_end;
 177
 178 /* need this so we can find the global registers: they never get saved. */
 179 CORE_ADDR global_reg_offset;
 180 static CORE_ADDR last_frame_address;
 181 CORE_ADDR last_frame_offset;
 182
 183
 184 /* Address in core file of start of register window stack area.
 185    Don't know if is this any of meaningful, useful or necessary.   */
 186 extern int reg_stack_offset;
 187
 188 #endif /* PYRAMID_CORE */
 189
 190 \f
 191 /* Work with core dump and executable files, for GDB.
 192    This code would be in core.c if it weren't machine-dependent. */
 193
 194 void
 195 core_file_command (filename, from_tty)
 196      char *filename;
 197      int from_tty;
 198 {
 199   int val;
 200   extern char registers[];
 201
 202   /* Discard all vestiges of any previous core file
 203      and mark data and stack spaces as empty.  */
 204
 205   if (corefile)
 206     free (corefile);
 207   corefile = 0;
 208
 209   if (corechan >= 0)
 210     close (corechan);
 211   corechan = -1;
 212
 213   data_start = 0;
 214   data_end = 0;
 215   stack_start = STACK_END_ADDR;
 216   stack_end = STACK_END_ADDR;
 217
 218 #ifdef PYRAMID_CORE
 219   reg_stack_start = CONTROL_STACK_ADDR;
 220   reg_stack_end = CONTROL_STACK_ADDR;   /* this isn't strictly true...*/
 221 #endif /* PYRAMID_CORE */
 222
 223   /* Now, if a new core file was specified, open it and digest it.  */
 224
 225   if (filename)
 226     {
 227       filename = tilde_expand (filename);
 228       make_cleanup (free, filename);
 229
 230       if (have_inferior_p ())
 231         error ("To look at a core file, you must kill the inferior with \"kill\".");
 232       corechan = open (filename, O_RDONLY, 0);
 233       if (corechan < 0)
 234         perror_with_name (filename);
 235       /* 4.2-style (and perhaps also sysV-style) core dump file.  */
 236       {
 237         struct user u;
 238
 239         unsigned int reg_offset;
 240
 241         val = myread (corechan, &u, sizeof u);
 242         if (val < 0)
 243           perror_with_name ("Not a core file: reading upage");
 244         if (val != sizeof u)
 245           error ("Not a core file: could only read %d bytes", val);
 246         data_start = exec_data_start;
 247
 248         data_end = data_start + NBPG * u.u_dsize;
 249         data_offset = NBPG * UPAGES;
 250         stack_offset = NBPG * (UPAGES + u.u_dsize);
 251
 252         /* find registers in core file */
 253 #ifdef PYRAMID_PTRACE
 254         stack_start = stack_end - NBPG * u.u_ussize;
 255         reg_stack_offset = stack_offset + (NBPG *u.u_ussize);
 256         reg_stack_end = reg_stack_start + NBPG * u.u_cssize;
 257
 258         last_frame_address = ((int) u.u_pcb.pcb_csp);
 259         last_frame_offset = reg_stack_offset + last_frame_address
 260                 - CONTROL_STACK_ADDR ;
 261         global_reg_offset = (char *)&u - (char *)&u.u_pcb.pcb_gr0 ;
 262
 263         /* skip any control-stack frames that were executed in the
 264            kernel. */
 265
 266         while (1) {
 267             char buf[4];
 268             val = lseek (corechan, last_frame_offset+(47*4), 0);
 269             if (val < 0)
 270                     perror_with_name (filename);
 271             val = myread (corechan, buf, sizeof buf);
 272             if (val < 0)
 273                     perror_with_name (filename);
 274
 275             if (*(int *)buf >= 0)
 276                     break;
 277             printf ("skipping frame %s\n", local_hex_string (last_frame_address));
 278             last_frame_offset -= CONTROL_STACK_FRAME_SIZE;
 279             last_frame_address -= CONTROL_STACK_FRAME_SIZE;
 280         }
 281         reg_offset = last_frame_offset;
 282
 283 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 284         printf ("Control stack pointer = %s\n",
 285                 local_hex_string (u.u_pcb.pcb_csp));
 286         printf ("offset to control stack %d outermost frame %d (%s)\n",
 287               reg_stack_offset, reg_offset, local_hex_string (last_frame_address));
 288 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 289
 290 #else /* not PYRAMID_CORE */
 291         stack_start = stack_end - NBPG * u.u_ssize;
 292         reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;
 293 #endif /* not PYRAMID_CORE */
 294
 295 #ifdef __not_on_pyr_yet
 296         /* Some machines put an absolute address in here and some put
 297            the offset in the upage of the regs.  */
 298         reg_offset = (int) u.u_ar0;
 299         if (reg_offset > NBPG * UPAGES)
 300           reg_offset -= KERNEL_U_ADDR;
 301 #endif
 302
 303         /* I don't know where to find this info.
 304            So, for now, mark it as not available.  */
 305         N_SET_MAGIC (core_aouthdr, 0);
 306
 307         /* Read the register values out of the core file and store
 308            them where `read_register' will find them.  */
 309
 310         {
 311           register int regno;
 312
 313           for (regno = 0; regno < 64; regno++)
 314             {
 315               char buf[MAX_REGISTER_RAW_SIZE];
 316
 317               val = lseek (corechan, register_addr (regno, reg_offset), 0);
 318               if (val < 0
 319                   || (val = myread (corechan, buf, sizeof buf)) < 0)
 320                 {
 321                   char * buffer = (char *) alloca (strlen (reg_names[regno])
 322                                                    + 30);
 323                   strcpy (buffer, "Reading register ");
 324                   strcat (buffer, reg_names[regno]);
 325
 326                   perror_with_name (buffer);
 327                 }
 328
 329               if (val < 0)
 330                 perror_with_name (filename);
 331 #ifdef PYRAMID_CONTROL_FRAME_DEBUGGING
 332       printf ("[reg %s(%d), offset in file %s=0x%0x, addr =0x%0x, =%0x]\n",
 333               reg_names[regno], regno, filename,
 334               register_addr(regno, reg_offset),
 335               regno * 4 + last_frame_address,
 336               *((int *)buf));
 337 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 338               supply_register (regno, buf);
 339             }
 340         }
 341       }
 342       if (filename[0] == '/')
 343         corefile = savestring (filename, strlen (filename));
 344       else
 345         {
 346           corefile = concat (current_directory, "/", filename, NULL);
 347         }
 348
 349 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 350       printf ("Providing CSP (%s) as nominal address of current frame.\n",
 351               local_hex_string(last_frame_address));
 352 #endif PYRAMID_CONTROL_FRAME_DEBUGGING
 353       /* FIXME: Which of the following is correct? */
 354 #if 0
 355       set_current_frame ( create_new_frame (read_register (FP_REGNUM),
 356                                             read_pc ()));
 357 #else
 358       set_current_frame ( create_new_frame (last_frame_address,
 359                                             read_pc ()));
 360 #endif
 361
 362       select_frame (get_current_frame (), 0);
 363       validate_files ();
 364     }
 365   else if (from_tty)
 366     printf ("No core file now.\n");
 367 }