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