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 <stdio.h>
  21 #include "defs.h"
  22 #include "frame.h"
  23 #include "inferior.h"
  24
  25 #include <sys/param.h>
  26 #include <sys/dir.h>
  27 #include <signal.h>
  28 #include <sys/ioctl.h>
  29 /* #include <fcntl.h>  Can we live without this?  */
  30
  31 #include "gdbcore.h"
  32 #include <sys/user.h>           /* After a.out.h  */
  33 #include <sys/file.h>
  34 #include <sys/stat.h>
  35
  36 \f
  37 void
  38 fetch_inferior_registers (regno)
  39      int regno;
  40 {
  41   register int datum;
  42   register unsigned int regaddr;
  43   int reg_buf[NUM_REGS+1];
  44   struct user u;
  45   register int skipped_frames = 0;
  46
  47   registers_fetched ();
  48
  49   for (regno = 0; regno < 64; regno++) {
  50     reg_buf[regno] = ptrace (3, inferior_pid, regno, 0);
  51
  52 #if defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
  53     printf ("Fetching %s from inferior, got %0x\n",
  54             reg_names[regno],
  55             reg_buf[regno]);
  56 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
  57
  58     if (reg_buf[regno] == -1 && errno == EIO) {
  59       printf("fetch_interior_registers: fetching %s from inferior\n",
  60              reg_names[regno]);
  61       errno = 0;
  62     }
  63     supply_register (regno, reg_buf+regno);
  64   }
  65   /* that leaves regs 64, 65, and 66 */
  66   datum = ptrace (3, inferior_pid,
  67                   ((char *)&u.u_pcb.pcb_csp) -
  68                   ((char *)&u), 0);
  69
  70
  71
  72   /* FIXME: Find the Current Frame Pointer (CFP). CFP is a global
  73      register (ie, NOT windowed), that gets saved in a frame iff
  74      the code for that frame has a prologue (ie, "adsf N").  If
  75      there is a prologue, the adsf insn saves the old cfp in
  76      pr13, cfp is set to sp, and N bytes of locals are allocated
  77      (sp is decremented by n).
  78      This makes finding CFP hard. I guess the right way to do it
  79      is:
  80      - If this is the innermost frame, believe ptrace() or
  81      the core area.
  82      - Otherwise:
  83      Find the first insn of the current frame.
  84      - find the saved pc;
  85      - find the call insn that saved it;
  86      - figure out where the call is to;
  87      - if the first insn is an adsf, we got a frame
  88      pointer. */
  89
  90
  91   /* Normal processors have separate stack pointers for user and
  92      kernel mode. Getting the last user mode frame on such
  93      machines is easy: the kernel context of the ptrace()'d
  94      process is on the kernel stack, and the USP points to what
  95      we want. But Pyramids only have a single cfp for both user and
  96      kernel mode.  And processes being ptrace()'d have some
  97      kernel-context control frames on their stack.
  98      To avoid tracing back into the kernel context of an inferior,
  99      we skip 0 or more contiguous control frames where the pc is
 100      in the kernel. */
 101
 102   while (1) {
 103     register int inferior_saved_pc;
 104     inferior_saved_pc = ptrace (1, inferior_pid, datum+((32+15)*4), 0);
 105     if (inferior_saved_pc > 0) break;
 106 #if defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 107     printf("skipping kernel frame %08x, pc=%08x\n", datum,
 108            inferior_saved_pc);
 109 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 110     skipped_frames++;
 111     datum -= CONTROL_STACK_FRAME_SIZE;
 112   }
 113
 114   reg_buf[CSP_REGNUM] = datum;
 115   supply_register(CSP_REGNUM, reg_buf+CSP_REGNUM);
 116 #ifdef  PYRAMID_CONTROL_FRAME_DEBUGGING
 117   if (skipped_frames) {
 118     fprintf (stderr,
 119              "skipped %d frames from %x to %x; cfp was %x, now %x\n",
 120              skipped_frames, reg_buf[CSP_REGNUM]);
 121   }
 122 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 123 }
 124
 125 /* Store our register values back into the inferior.
 126    If REGNO is -1, do this for all registers.
 127    Otherwise, REGNO specifies which register (so we can save time).  */
 128
 129 void
 130 store_inferior_registers (regno)
 131      int regno;
 132 {
 133   register unsigned int regaddr;
 134   char buf[80];
 135
 136   if (regno >= 0)
 137     {
 138       if ((0 <= regno) && (regno < 64)) {
 139         /*regaddr = register_addr (regno, offset);*/
 140         regaddr = regno;
 141         errno = 0;
 142         ptrace (6, inferior_pid, regaddr, read_register (regno));
 143         if (errno != 0)
 144           {
 145             sprintf (buf, "writing register number %d", regno);
 146             perror_with_name (buf);
 147           }
 148       }
 149     }
 150   else
 151     {
 152       for (regno = 0; regno < NUM_REGS; regno++)
 153         {
 154           /*regaddr = register_addr (regno, offset);*/
 155           regaddr = regno;
 156           errno = 0;
 157           ptrace (6, inferior_pid, regaddr, read_register (regno));
 158           if (errno != 0)
 159             {
 160               sprintf (buf, "writing all regs, number %d", regno);
 161               perror_with_name (buf);
 162             }
 163         }
 164 }
 165 \f
 166 /*** Extensions to  core and dump files, for GDB. */
 167
 168 extern unsigned int last_frame_offset;
 169
 170 #ifdef PYRAMID_CORE
 171
 172 /* Can't make definitions here static, since core.c needs them
 173    to do bounds checking on the core-file areas. O well. */
 174
 175 /* have two stacks: one for data, one for register windows. */
 176 extern CORE_ADDR reg_stack_start;
 177 extern CORE_ADDR reg_stack_end;
 178
 179 /* need this so we can find the global registers: they never get saved. */
 180 CORE_ADDR global_reg_offset;
 181 static CORE_ADDR last_frame_address;
 182 CORE_ADDR last_frame_offset;
 183
 184
 185 /* Address in core file of start of register window stack area.
 186    Don't know if is this any of meaningful, useful or necessary.   */
 187 extern int reg_stack_offset;
 188
 189 #endif /* PYRAMID_CORE */
 190
 191 \f
 192 /* Work with core dump and executable files, for GDB.
 193    This code would be in core.c if it weren't machine-dependent. */
 194
 195 void
 196 core_file_command (filename, from_tty)
 197      char *filename;
 198      int from_tty;
 199 {
 200   int val;
 201   extern char registers[];
 202
 203   /* Discard all vestiges of any previous core file
 204      and mark data and stack spaces as empty.  */
 205
 206   if (corefile)
 207     free (corefile);
 208   corefile = 0;
 209
 210   if (corechan >= 0)
 211     close (corechan);
 212   corechan = -1;
 213
 214   data_start = 0;
 215   data_end = 0;
 216   stack_start = STACK_END_ADDR;
 217   stack_end = STACK_END_ADDR;
 218
 219 #ifdef PYRAMID_CORE
 220   reg_stack_start = CONTROL_STACK_ADDR;
 221   reg_stack_end = CONTROL_STACK_ADDR;   /* this isn't strictly true...*/
 222 #endif /* PYRAMID_CORE */
 223
 224   /* Now, if a new core file was specified, open it and digest it.  */
 225
 226   if (filename)
 227     {
 228       filename = tilde_expand (filename);
 229       make_cleanup (free, filename);
 230
 231       if (have_inferior_p ())
 232         error ("To look at a core file, you must kill the inferior with \"kill\".");
 233       corechan = open (filename, O_RDONLY, 0);
 234       if (corechan < 0)
 235         perror_with_name (filename);
 236       /* 4.2-style (and perhaps also sysV-style) core dump file.  */
 237       {
 238         struct user u;
 239
 240         unsigned int reg_offset;
 241
 242         val = myread (corechan, &u, sizeof u);
 243         if (val < 0)
 244           perror_with_name ("Not a core file: reading upage");
 245         if (val != sizeof u)
 246           error ("Not a core file: could only read %d bytes", val);
 247         data_start = exec_data_start;
 248
 249         data_end = data_start + NBPG * u.u_dsize;
 250         data_offset = NBPG * UPAGES;
 251         stack_offset = NBPG * (UPAGES + u.u_dsize);
 252
 253         /* find registers in core file */
 254 #ifdef PYRAMID_PTRACE
 255         stack_start = stack_end - NBPG * u.u_ussize;
 256         reg_stack_offset = stack_offset + (NBPG *u.u_ussize);
 257         reg_stack_end = reg_stack_start + NBPG * u.u_cssize;
 258
 259         last_frame_address = ((int) u.u_pcb.pcb_csp);
 260         last_frame_offset = reg_stack_offset + last_frame_address
 261                 - CONTROL_STACK_ADDR ;
 262         global_reg_offset = (char *)&u - (char *)&u.u_pcb.pcb_gr0 ;
 263
 264         /* skip any control-stack frames that were executed in the
 265            kernel. */
 266
 267         while (1) {
 268             char buf[4];
 269             val = lseek (corechan, last_frame_offset+(47*4), 0);
 270             if (val < 0)
 271                     perror_with_name (filename);
 272             val = myread (corechan, buf, sizeof buf);
 273             if (val < 0)
 274                     perror_with_name (filename);
 275
 276             if (*(int *)buf >= 0)
 277                     break;
 278             printf ("skipping frame %s\n", local_hex_string (last_frame_address));
 279             last_frame_offset -= CONTROL_STACK_FRAME_SIZE;
 280             last_frame_address -= CONTROL_STACK_FRAME_SIZE;
 281         }
 282         reg_offset = last_frame_offset;
 283
 284 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 285         printf ("Control stack pointer = %s\n",
 286                 local_hex_string (u.u_pcb.pcb_csp));
 287         printf ("offset to control stack %d outermost frame %d (%s)\n",
 288               reg_stack_offset, reg_offset, local_hex_string (last_frame_address));
 289 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 290
 291 #else /* not PYRAMID_CORE */
 292         stack_start = stack_end - NBPG * u.u_ssize;
 293         reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;
 294 #endif /* not PYRAMID_CORE */
 295
 296 #ifdef __not_on_pyr_yet
 297         /* Some machines put an absolute address in here and some put
 298            the offset in the upage of the regs.  */
 299         reg_offset = (int) u.u_ar0;
 300         if (reg_offset > NBPG * UPAGES)
 301           reg_offset -= KERNEL_U_ADDR;
 302 #endif
 303
 304         /* I don't know where to find this info.
 305            So, for now, mark it as not available.  */
 306         N_SET_MAGIC (core_aouthdr, 0);
 307
 308         /* Read the register values out of the core file and store
 309            them where `read_register' will find them.  */
 310
 311         {
 312           register int regno;
 313
 314           for (regno = 0; regno < 64; regno++)
 315             {
 316               char buf[MAX_REGISTER_RAW_SIZE];
 317
 318               val = lseek (corechan, register_addr (regno, reg_offset), 0);
 319               if (val < 0
 320                   || (val = myread (corechan, buf, sizeof buf)) < 0)
 321                 {
 322                   char * buffer = (char *) alloca (strlen (reg_names[regno])
 323                                                    + 30);
 324                   strcpy (buffer, "Reading register ");
 325                   strcat (buffer, reg_names[regno]);
 326
 327                   perror_with_name (buffer);
 328                 }
 329
 330               if (val < 0)
 331                 perror_with_name (filename);
 332 #ifdef PYRAMID_CONTROL_FRAME_DEBUGGING
 333       printf ("[reg %s(%d), offset in file %s=0x%0x, addr =0x%0x, =%0x]\n",
 334               reg_names[regno], regno, filename,
 335               register_addr(regno, reg_offset),
 336               regno * 4 + last_frame_address,
 337               *((int *)buf));
 338 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 339               supply_register (regno, buf);
 340             }
 341         }
 342       }
 343       if (filename[0] == '/')
 344         corefile = savestring (filename, strlen (filename));
 345       else
 346         {
 347           corefile = concat (current_directory, "/", filename, NULL);
 348         }
 349
 350 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 351       printf ("Providing CSP (%s) as nominal address of current frame.\n",
 352               local_hex_string(last_frame_address));
 353 #endif PYRAMID_CONTROL_FRAME_DEBUGGING
 354       /* FIXME: Which of the following is correct? */
 355 #if 0
 356       set_current_frame ( create_new_frame (read_register (FP_REGNUM),
 357                                             read_pc ()));
 358 #else
 359       set_current_frame ( create_new_frame (last_frame_address,
 360                                             read_pc ()));
 361 #endif
 362
 363       select_frame (get_current_frame (), 0);
 364       validate_files ();
 365     }
 366   else if (from_tty)
 367     printf ("No core file now.\n");
 368 }