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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 "gdb_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, (PTRACE_ARG3_TYPE) regno, 0);
  50
  51 #if defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
  52     printf_unfiltered ("Fetching register %s, got %0x\n",
  53             REGISTER_NAME (regno),
  54             reg_buf[regno]);
  55 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
  56
  57     if (reg_buf[regno] == -1 && errno == EIO) {
  58       printf_unfiltered("fetch_interior_registers: fetching register %s\n",
  59              REGISTER_NAME (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                   (PTRACE_ARG3_TYPE) (((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,
 104                                 (PTRACE_ARG3_TYPE) (datum+((32+15)*4)), 0);
 105     if (inferior_saved_pc > 0) break;
 106 #if defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 107     printf_unfiltered("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_unfiltered (gdb_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, (PTRACE_ARG3_TYPE) regaddr,
 143                 read_register (regno));
 144         if (errno != 0)
 145           {
 146             sprintf (buf, "writing register number %d", regno);
 147             perror_with_name (buf);
 148           }
 149       }
 150     }
 151   else
 152     {
 153       for (regno = 0; regno < NUM_REGS; regno++)
 154         {
 155           /*regaddr = register_addr (regno, offset);*/
 156           regaddr = regno;
 157           errno = 0;
 158           ptrace (6, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
 159                   read_register (regno));
 160           if (errno != 0)
 161             {
 162               sprintf (buf, "writing all regs, number %d", regno);
 163               perror_with_name (buf);
 164             }
 165         }
 166 }
 167 \f
 168 /*** Extensions to  core and dump files, for GDB. */
 169
 170 extern unsigned int last_frame_offset;
 171
 172 #ifdef PYRAMID_CORE
 173
 174 /* Can't make definitions here static, since corefile.c needs them
 175    to do bounds checking on the core-file areas. O well. */
 176
 177 /* have two stacks: one for data, one for register windows. */
 178 extern CORE_ADDR reg_stack_start;
 179 extern CORE_ADDR reg_stack_end;
 180
 181 /* need this so we can find the global registers: they never get saved. */
 182 CORE_ADDR global_reg_offset;
 183 static CORE_ADDR last_frame_address;
 184 CORE_ADDR last_frame_offset;
 185
 186
 187 /* Address in core file of start of register window stack area.
 188    Don't know if is this any of meaningful, useful or necessary.   */
 189 extern int reg_stack_offset;
 190
 191 #endif /* PYRAMID_CORE */
 192
 193 \f
 194 /* Work with core dump and executable files, for GDB.
 195    This code would be in corefile.c if it weren't machine-dependent. */
 196
 197 void
 198 core_file_command (filename, from_tty)
 199      char *filename;
 200      int from_tty;
 201 {
 202   int val;
 203   extern char registers[];
 204
 205   /* Discard all vestiges of any previous core file
 206      and mark data and stack spaces as empty.  */
 207
 208   if (corefile)
 209     free (corefile);
 210   corefile = 0;
 211
 212   if (corechan >= 0)
 213     close (corechan);
 214   corechan = -1;
 215
 216   data_start = 0;
 217   data_end = 0;
 218   stack_start = STACK_END_ADDR;
 219   stack_end = STACK_END_ADDR;
 220
 221 #ifdef PYRAMID_CORE
 222   reg_stack_start = CONTROL_STACK_ADDR;
 223   reg_stack_end = CONTROL_STACK_ADDR;   /* this isn't strictly true...*/
 224 #endif /* PYRAMID_CORE */
 225
 226   /* Now, if a new core file was specified, open it and digest it.  */
 227
 228   if (filename)
 229     {
 230       filename = tilde_expand (filename);
 231       make_cleanup (free, filename);
 232
 233       if (have_inferior_p ())
 234         error ("To look at a core file, you must kill the program with \"kill\".");
 235       corechan = open (filename, O_RDONLY, 0);
 236       if (corechan < 0)
 237         perror_with_name (filename);
 238       /* 4.2-style (and perhaps also sysV-style) core dump file.  */
 239       {
 240         struct user u;
 241
 242         unsigned int reg_offset;
 243
 244         val = myread (corechan, &u, sizeof u);
 245         if (val < 0)
 246           perror_with_name ("Not a core file: reading upage");
 247         if (val != sizeof u)
 248           error ("Not a core file: could only read %d bytes", val);
 249         data_start = exec_data_start;
 250
 251         data_end = data_start + NBPG * u.u_dsize;
 252         data_offset = NBPG * UPAGES;
 253         stack_offset = NBPG * (UPAGES + u.u_dsize);
 254
 255         /* find registers in core file */
 256 #ifdef PYRAMID_PTRACE
 257         stack_start = stack_end - NBPG * u.u_ussize;
 258         reg_stack_offset = stack_offset + (NBPG *u.u_ussize);
 259         reg_stack_end = reg_stack_start + NBPG * u.u_cssize;
 260
 261         last_frame_address = ((int) u.u_pcb.pcb_csp);
 262         last_frame_offset = reg_stack_offset + last_frame_address
 263                 - CONTROL_STACK_ADDR ;
 264         global_reg_offset = (char *)&u - (char *)&u.u_pcb.pcb_gr0 ;
 265
 266         /* skip any control-stack frames that were executed in the
 267            kernel. */
 268
 269         while (1) {
 270             char buf[4];
 271             val = lseek (corechan, last_frame_offset+(47*4), 0);
 272             if (val < 0)
 273                     perror_with_name (filename);
 274             val = myread (corechan, buf, sizeof buf);
 275             if (val < 0)
 276                     perror_with_name (filename);
 277
 278             if (*(int *)buf >= 0)
 279                     break;
 280             printf_unfiltered ("skipping frame %s\n", local_hex_string (last_frame_address));
 281             last_frame_offset -= CONTROL_STACK_FRAME_SIZE;
 282             last_frame_address -= CONTROL_STACK_FRAME_SIZE;
 283         }
 284         reg_offset = last_frame_offset;
 285
 286 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 287         printf_unfiltered ("Control stack pointer = %s\n",
 288                 local_hex_string (u.u_pcb.pcb_csp));
 289         printf_unfiltered ("offset to control stack %d outermost frame %d (%s)\n",
 290               reg_stack_offset, reg_offset, local_hex_string (last_frame_address));
 291 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 292
 293 #else /* not PYRAMID_CORE */
 294         stack_start = stack_end - NBPG * u.u_ssize;
 295         reg_offset = (int) u.u_ar0 - KERNEL_U_ADDR;
 296 #endif /* not PYRAMID_CORE */
 297
 298 #ifdef __not_on_pyr_yet
 299         /* Some machines put an absolute address in here and some put
 300            the offset in the upage of the regs.  */
 301         reg_offset = (int) u.u_ar0;
 302         if (reg_offset > NBPG * UPAGES)
 303           reg_offset -= KERNEL_U_ADDR;
 304 #endif
 305
 306         /* I don't know where to find this info.
 307            So, for now, mark it as not available.  */
 308         N_SET_MAGIC (core_aouthdr, 0);
 309
 310         /* Read the register values out of the core file and store
 311            them where `read_register' will find them.  */
 312
 313         {
 314           register int regno;
 315
 316           for (regno = 0; regno < 64; regno++)
 317             {
 318               char buf[MAX_REGISTER_RAW_SIZE];
 319
 320               val = lseek (corechan, register_addr (regno, reg_offset), 0);
 321               if (val < 0
 322                   || (val = myread (corechan, buf, sizeof buf)) < 0)
 323                 {
 324                   char * buffer = (char *) alloca (strlen (REGISTER_NAME (regno))
 325                                                    + 30);
 326                   strcpy (buffer, "Reading register ");
 327                   strcat (buffer, REGISTER_NAME (regno));
 328
 329                   perror_with_name (buffer);
 330                 }
 331
 332               if (val < 0)
 333                 perror_with_name (filename);
 334 #ifdef PYRAMID_CONTROL_FRAME_DEBUGGING
 335       printf_unfiltered ("[reg %s(%d), offset in file %s=0x%0x, addr =0x%0x, =%0x]\n",
 336               REGISTER_NAME (regno), regno, filename,
 337               register_addr(regno, reg_offset),
 338               regno * 4 + last_frame_address,
 339               *((int *)buf));
 340 #endif /* PYRAMID_CONTROL_FRAME_DEBUGGING */
 341               supply_register (regno, buf);
 342             }
 343         }
 344       }
 345       if (filename[0] == '/')
 346         corefile = savestring (filename, strlen (filename));
 347       else
 348         {
 349           corefile = concat (current_directory, "/", filename, NULL);
 350         }
 351
 352 #if 1 || defined(PYRAMID_CONTROL_FRAME_DEBUGGING)
 353       printf_unfiltered ("Providing CSP (%s) as nominal address of current frame.\n",
 354               local_hex_string(last_frame_address));
 355 #endif PYRAMID_CONTROL_FRAME_DEBUGGING
 356       /* FIXME: Which of the following is correct? */
 357 #if 0
 358       set_current_frame ( create_new_frame (read_register (FP_REGNUM),
 359                                             read_pc ()));
 360 #else
 361       set_current_frame ( create_new_frame (last_frame_address,
 362                                             read_pc ()));
 363 #endif
 364
 365       select_frame (get_current_frame (), 0);
 366       validate_files ();
 367     }
 368   else if (from_tty)
 369     printf_unfiltered ("No core file now.\n");
 370 }