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 GDB 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 1, or (at your option)
   9 any later version.
  10
  11 GDB 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 GDB; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20 #include <stdio.h>
  21 #include "defs.h"
  22 #include "param.h"
  23 #include "frame.h"
  24 #include "inferior.h"
  25
  26 #include <sys/param.h>
  27 #include <sys/dir.h>
  28 #include <signal.h>
  29 #include <sys/ioctl.h>
  30 /* #include <fcntl.h>  Can we live without this?  */
  31
  32 #include "gdbcore.h"
  33 #include <sys/user.h>           /* After a.out.h  */
  34 #include <sys/file.h>
  35 #include <sys/stat.h>
  36 \f
  37 void
  38 fetch_inferior_registers ()
  39 {
  40   register int regno, 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 store_inferior_registers (regno)
 129      int regno;
 130 {
 131   register unsigned int regaddr;
 132   char buf[80];
 133
 134   if (regno >= 0)
 135     {
 136       if ((0 <= regno) && (regno < 64)) {
 137         /*regaddr = register_addr (regno, offset);*/
 138         regaddr = regno;
 139         errno = 0;
 140         ptrace (6, inferior_pid, regaddr, read_register (regno));
 141         if (errno != 0)
 142           {
 143             sprintf (buf, "writing register number %d", regno);
 144             perror_with_name (buf);
 145           }
 146       }
 147     }
 148   else
 149     {
 150       for (regno = 0; regno < NUM_REGS; regno++)
 151         {
 152           /*regaddr = register_addr (regno, offset);*/
 153           regaddr = regno;
 154           errno = 0;
 155           ptrace (6, inferior_pid, regaddr, read_register (regno));
 156           if (errno != 0)
 157             {
 158               sprintf (buf, "writing all regs, number %d", regno);
 159               perror_with_name (buf);
 160             }
 161         }
 162 }
 163 \f
 164 /*** Extensions to  core and dump files, for GDB. */
 165
 166 extern unsigned int last_frame_offset;
 167
 168 #ifdef PYRAMID_CORE
 169
 170 /* Can't make definitions here static, since core.c needs them
 171    to do bounds checking on the core-file areas. O well. */
 172
 173 /* have two stacks: one for data, one for register windows. */
 174 extern CORE_ADDR reg_stack_start;
 175 extern CORE_ADDR reg_stack_end;
 176
 177 /* need this so we can find the global registers: they never get saved. */
 178 CORE_ADDR global_reg_offset;
 179 static CORE_ADDR last_frame_address;
 180 CORE_ADDR last_frame_offset;
 181
 182
 183 /* Address in core file of start of register window stack area.
 184    Don't know if is this any of meaningful, useful or necessary.   */
 185 extern int reg_stack_offset;
 186
 187 #endif /* PYRAMID_CORE */
 188
 189 \f
 190 /* Work with core dump and executable files, for GDB.
 191    This code would be in core.c if it weren't machine-dependent. */
 192
 193 void
 194 core_file_command (filename, from_tty)
 195      char *filename;
 196      int from_tty;
 197 {
 198   int val;
 199   extern char registers[];
 200
 201   /* Discard all vestiges of any previous core file
 202      and mark data and stack spaces as empty.  */
 203
 204   if (corefile)
 205     free (corefile);
 206   corefile = 0;
 207
 208   if (corechan >= 0)
 209     close (corechan);
 210   corechan = -1;
 211
 212   data_start = 0;
 213   data_end = 0;
 214   stack_start = STACK_END_ADDR;
 215   stack_end = STACK_END_ADDR;
 216
 217 #ifdef PYRAMID_CORE
 218   reg_stack_start = CONTROL_STACK_ADDR;
 219   reg_stack_end = CONTROL_STACK_ADDR;   /* this isn't strictly true...*/
 220 #endif /* PYRAMID_CORE */
 221
 222   /* Now, if a new core file was specified, open it and digest it.  */
 223
 224   if (filename)
 225     {
 226       filename = tilde_expand (filename);
 227       make_cleanup (free, filename);
 228
 229       if (have_inferior_p ())
 230         error ("To look at a core file, you must kill the inferior with \"kill\".");
 231       corechan = open (filename, O_RDONLY, 0);
 232       if (corechan < 0)
 233         perror_with_name (filename);
 234       /* 4.2-style (and perhaps also sysV-style) core dump file.  */
 235       {
 236         struct user u;
 237
 238         unsigned int reg_offset;
 239
 240         val = myread (corechan, &u, sizeof u);
 241         if (val < 0)
 242           perror_with_name ("Not a core file: reading upage");
 243         if (val != sizeof u)
 244           error ("Not a core file: could only read %d bytes", val);
 245         data_start = exec_data_start;
 246
 247         data_end = data_start + NBPG * u.u_dsize;
 248         data_offset = NBPG * UPAGES;
 249         stack_offset = NBPG * (UPAGES + u.u_dsize);
 250
 251         /* find registers in core file */
 252 #ifdef PYRAMID_PTRACE
 253         stack_start = stack_end - NBPG * u.u_ussize;
 254         reg_stack_offset = stack_offset + (NBPG *u.u_ussize);
 255         reg_stack_end = reg_stack_start + NBPG * u.u_cssize;
 256
 257         last_frame_address = ((int) u.u_pcb.pcb_csp);
 258         last_frame_offset = reg_stack_offset + last_frame_address
 259                 - CONTROL_STACK_ADDR ;
 260         global_reg_offset = (char *)&u - (char *)&u.u_pcb.pcb_gr0 ;
 261
 262         /* skip any control-stack frames that were executed in the
 263            kernel. */
 264
 265         while (1) {
 266             char buf[4];
 267             val = lseek (corechan, last_frame_offset+(47*4), 0);
 268             if (val < 0)
 269                     perror_with_name (filename);
 270             val = myread (corechan, buf, sizeof buf);
 271             if (val < 0)
 272                     perror_with_name (filename);
 273
 274             if (*(int *)buf >= 0)
 275                     break;
 276             printf ("skipping frame %0x\n", last_frame_address);
 277             last_frame_offset -= CONTROL_STACK_FRAME_SIZE;
 278             last_frame_address -= CONTROL_STACK_FRAME_SIZE;
 279         }
 280         reg_offset = last_frame_offset;
 281
 282 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 283         printf ("Control stack pointer = 0x%08x\n",
 284                 u.u_pcb.pcb_csp);
 285         printf ("offset to control stack %d outermost frame %d (%0x)\n",
 286               reg_stack_offset, reg_offset, last_frame_address);
 287 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 288
 289 #else /* not PYRAMID_CORE */
 290         stack_start = stack_end - NBPG * u.u_ssize;
 291         reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;
 292 #endif /* not PYRAMID_CORE */
 293
 294 #ifdef __not_on_pyr_yet
 295         /* Some machines put an absolute address in here and some put
 296            the offset in the upage of the regs.  */
 297         reg_offset = (int) u.u_ar0;
 298         if (reg_offset > NBPG * UPAGES)
 299           reg_offset -= KERNEL_U_ADDR;
 300 #endif
 301
 302         /* I don't know where to find this info.
 303            So, for now, mark it as not available.  */
 304         N_SET_MAGIC (core_aouthdr, 0);
 305
 306         /* Read the register values out of the core file and store
 307            them where `read_register' will find them.  */
 308
 309         {
 310           register int regno;
 311
 312           for (regno = 0; regno < 64; regno++)
 313             {
 314               char buf[MAX_REGISTER_RAW_SIZE];
 315
 316               val = lseek (corechan, register_addr (regno, reg_offset), 0);
 317               if (val < 0
 318                   || (val = myread (corechan, buf, sizeof buf)) < 0)
 319                 {
 320                   char * buffer = (char *) alloca (strlen (reg_names[regno])
 321                                                    + 30);
 322                   strcpy (buffer, "Reading register ");
 323                   strcat (buffer, reg_names[regno]);
 324
 325                   perror_with_name (buffer);
 326                 }
 327
 328               if (val < 0)
 329                 perror_with_name (filename);
 330 #ifdef PYRAMID_CONTROL_FRAME_DEBUGGING
 331       printf ("[reg %s(%d), offset in file %s=0x%0x, addr =0x%0x, =%0x]\n",
 332               reg_names[regno], regno, filename,
 333               register_addr(regno, reg_offset),
 334               regno * 4 + last_frame_address,
 335               *((int *)buf));
 336 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 337               supply_register (regno, buf);
 338             }
 339         }
 340       }
 341       if (filename[0] == '/')
 342         corefile = savestring (filename, strlen (filename));
 343       else
 344         {
 345           corefile = concat (current_directory, "/", filename);
 346         }
 347
 348 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 349       printf ("Providing CSP (%0x) as nominal address of current frame.\n",
 350               last_frame_address);
 351 #endif PYRAMID_CONTROL_FRAME_DEBUGGING
 352       /* FIXME: Which of the following is correct? */
 353 #if 0
 354       set_current_frame ( create_new_frame (read_register (FP_REGNUM),
 355                                             read_pc ()));
 356 #else
 357       set_current_frame ( create_new_frame (last_frame_address,
 358                                             read_pc ()));
 359 #endif
 360
 361       select_frame (get_current_frame (), 0);
 362       validate_files ();
 363     }
 364   else if (from_tty)
 365     printf ("No core file now.\n");
 366 }