gdb/m68klinux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright 1996, 1998, 2000, 2001, 2002 Free Software Foundation,
   4    Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, USA.  */
  22
  23 #include "defs.h"
  24 #include "frame.h"
  25 #include "inferior.h"
  26 #include "language.h"
  27 #include "gdbcore.h"
  28 #include "gdb_string.h"
  29 #include "regcache.h"
  30
  31 #include "m68k-tdep.h"
  32
  33 #ifdef USG
  34 #include <sys/types.h>
  35 #endif
  36
  37 #include <sys/param.h>
  38 #include <sys/dir.h>
  39 #include <signal.h>
  40 #include <sys/ptrace.h>
  41 #include <sys/user.h>
  42 #include <sys/ioctl.h>
  43 #include <fcntl.h>
  44 #include <sys/procfs.h>
  45
  46 #ifdef HAVE_SYS_REG_H
  47 #include <sys/reg.h>
  48 #endif
  49
  50 #include <sys/file.h>
  51 #include "gdb_stat.h"
  52
  53 #include "floatformat.h"
  54
  55 #include "target.h"
  56 \f
  57 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  58 static const int regmap[] =
  59 {
  60   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  61   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  62   PT_SR, PT_PC,
  63   /* PT_FP0, ..., PT_FP7 */
  64   21, 24, 27, 30, 33, 36, 39, 42,
  65   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  66   45, 46, 47
  67 };
  68
  69 /* Which ptrace request retrieves which registers?
  70    These apply to the corresponding SET requests as well.  */
  71 #define NUM_GREGS (18)
  72 #define MAX_NUM_REGS (NUM_GREGS + 11)
  73
  74 int
  75 getregs_supplies (int regno)
  76 {
  77   return 0 <= regno && regno < NUM_GREGS;
  78 }
  79
  80 int
  81 getfpregs_supplies (int regno)
  82 {
  83   return FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  84 }
  85
  86 /* Does the current host support the GETREGS request?  */
  87 int have_ptrace_getregs =
  88 #ifdef HAVE_PTRACE_GETREGS
  89   1
  90 #else
  91   0
  92 #endif
  93 ;
  94
  95 \f
  96
  97 /* BLOCKEND is the value of u.u_ar0, and points to the place where GS
  98    is stored.  */
  99
 100 int
 101 m68k_linux_register_u_addr (int blockend, int regnum)
 102 {
 103   return (blockend + 4 * regmap[regnum]);
 104 }
 105 \f
 106
 107 /* Fetching registers directly from the U area, one at a time.  */
 108
 109 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 110    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 111    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 112    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 113    fall back on that code when GDB is running on top of a kernel that
 114    doesn't support the GETREGS request.  */
 115
 116 #ifndef PT_READ_U
 117 #define PT_READ_U PTRACE_PEEKUSR
 118 #endif
 119 #ifndef PT_WRITE_U
 120 #define PT_WRITE_U PTRACE_POKEUSR
 121 #endif
 122
 123 /* Default the type of the ptrace transfer to int.  */
 124 #ifndef PTRACE_XFER_TYPE
 125 #define PTRACE_XFER_TYPE int
 126 #endif
 127
 128 /* Fetch one register.  */
 129
 130 static void
 131 fetch_register (int regno)
 132 {
 133   /* This isn't really an address.  But ptrace thinks of it as one.  */
 134   CORE_ADDR regaddr;
 135   char mess[128];               /* For messages */
 136   int i;
 137   unsigned int offset;          /* Offset of registers within the u area.  */
 138   char buf[MAX_REGISTER_SIZE];
 139   int tid;
 140
 141   if (CANNOT_FETCH_REGISTER (regno))
 142     {
 143       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 144       supply_register (regno, buf);
 145       return;
 146     }
 147
 148   /* Overload thread id onto process id */
 149   tid = TIDGET (inferior_ptid);
 150   if (tid == 0)
 151     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 152
 153   offset = U_REGS_OFFSET;
 154
 155   regaddr = register_addr (regno, offset);
 156   for (i = 0; i < register_size (current_gdbarch, regno);
 157        i += sizeof (PTRACE_XFER_TYPE))
 158     {
 159       errno = 0;
 160       *(PTRACE_XFER_TYPE *) &buf[i] = ptrace (PT_READ_U, tid,
 161                                               (PTRACE_ARG3_TYPE) regaddr, 0);
 162       regaddr += sizeof (PTRACE_XFER_TYPE);
 163       if (errno != 0)
 164         {
 165           sprintf (mess, "reading register %s (#%d)",
 166                    REGISTER_NAME (regno), regno);
 167           perror_with_name (mess);
 168         }
 169     }
 170   supply_register (regno, buf);
 171 }
 172
 173 /* Fetch register values from the inferior.
 174    If REGNO is negative, do this for all registers.
 175    Otherwise, REGNO specifies which register (so we can save time). */
 176
 177 void
 178 old_fetch_inferior_registers (int regno)
 179 {
 180   if (regno >= 0)
 181     {
 182       fetch_register (regno);
 183     }
 184   else
 185     {
 186       for (regno = 0; regno < NUM_REGS; regno++)
 187         {
 188           fetch_register (regno);
 189         }
 190     }
 191 }
 192
 193 /* Store one register. */
 194
 195 static void
 196 store_register (int regno)
 197 {
 198   /* This isn't really an address.  But ptrace thinks of it as one.  */
 199   CORE_ADDR regaddr;
 200   char mess[128];               /* For messages */
 201   int i;
 202   unsigned int offset;          /* Offset of registers within the u area.  */
 203   int tid;
 204   char buf[MAX_REGISTER_SIZE];
 205
 206   if (CANNOT_STORE_REGISTER (regno))
 207     {
 208       return;
 209     }
 210
 211   /* Overload thread id onto process id */
 212   tid = TIDGET (inferior_ptid);
 213   if (tid == 0)
 214     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 215
 216   offset = U_REGS_OFFSET;
 217
 218   regaddr = register_addr (regno, offset);
 219
 220   /* Put the contents of regno into a local buffer */
 221   regcache_collect (regno, buf);
 222
 223   /* Store the local buffer into the inferior a chunk at the time. */
 224   for (i = 0; i < register_size (current_gdbarch, regno);
 225        i += sizeof (PTRACE_XFER_TYPE))
 226     {
 227       errno = 0;
 228       ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
 229               *(PTRACE_XFER_TYPE *) (buf + i));
 230       regaddr += sizeof (PTRACE_XFER_TYPE);
 231       if (errno != 0)
 232         {
 233           sprintf (mess, "writing register %s (#%d)",
 234                    REGISTER_NAME (regno), regno);
 235           perror_with_name (mess);
 236         }
 237     }
 238 }
 239
 240 /* Store our register values back into the inferior.
 241    If REGNO is negative, do this for all registers.
 242    Otherwise, REGNO specifies which register (so we can save time).  */
 243
 244 void
 245 old_store_inferior_registers (int regno)
 246 {
 247   if (regno >= 0)
 248     {
 249       store_register (regno);
 250     }
 251   else
 252     {
 253       for (regno = 0; regno < NUM_REGS; regno++)
 254         {
 255           store_register (regno);
 256         }
 257     }
 258 }
 259 \f
 260 /*  Given a pointer to a general register set in /proc format
 261    (elf_gregset_t *), unpack the register contents and supply
 262    them as gdb's idea of the current register values. */
 263
 264
 265 /* Note both m68k-tdep.c and m68klinux-nat.c contain definitions
 266    for supply_gregset and supply_fpregset. The definitions
 267    in m68k-tdep.c are valid if USE_PROC_FS is defined. Otherwise,
 268    the definitions in m68klinux-nat.c will be used. This is a
 269    bit of a hack. The supply_* routines do not belong in
 270    *_tdep.c files. But, there are several lynx ports that currently
 271    depend on these definitions. */
 272
 273 #ifndef USE_PROC_FS
 274
 275 /* Prototypes for supply_gregset etc. */
 276 #include "gregset.h"
 277
 278 void
 279 supply_gregset (elf_gregset_t *gregsetp)
 280 {
 281   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 282   int regi;
 283
 284   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 285     supply_register (regi, (char *) &regp[regmap[regi]]);
 286   supply_register (PS_REGNUM, (char *) &regp[PT_SR]);
 287   supply_register (PC_REGNUM, (char *) &regp[PT_PC]);
 288 }
 289
 290 /* Fill register REGNO (if it is a general-purpose register) in
 291    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 292    do this for all registers.  */
 293 void
 294 fill_gregset (elf_gregset_t *gregsetp, int regno)
 295 {
 296   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 297   int i;
 298
 299   for (i = 0; i < NUM_GREGS; i++)
 300     if (regno == -1 || regno == i)
 301       regcache_collect (i, regp + regmap[i]);
 302 }
 303
 304 #ifdef HAVE_PTRACE_GETREGS
 305
 306 /* Fetch all general-purpose registers from process/thread TID and
 307    store their values in GDB's register array.  */
 308
 309 static void
 310 fetch_regs (int tid)
 311 {
 312   elf_gregset_t regs;
 313
 314   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 315     {
 316       if (errno == EIO)
 317         {
 318           /* The kernel we're running on doesn't support the GETREGS
 319              request.  Reset `have_ptrace_getregs'.  */
 320           have_ptrace_getregs = 0;
 321           return;
 322         }
 323
 324       perror_with_name ("Couldn't get registers");
 325     }
 326
 327   supply_gregset (&regs);
 328 }
 329
 330 /* Store all valid general-purpose registers in GDB's register array
 331    into the process/thread specified by TID.  */
 332
 333 static void
 334 store_regs (int tid, int regno)
 335 {
 336   elf_gregset_t regs;
 337
 338   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 339     perror_with_name ("Couldn't get registers");
 340
 341   fill_gregset (&regs, regno);
 342
 343   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 344     perror_with_name ("Couldn't write registers");
 345 }
 346
 347 #else
 348
 349 static void fetch_regs (int tid) {}
 350 static void store_regs (int tid, int regno) {}
 351
 352 #endif
 353
 354 \f
 355 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 356
 357 /* What is the address of fpN within the floating-point register set F?  */
 358 #define FPREG_ADDR(f, n) ((char *) &(f)->fpregs[(n) * 3])
 359
 360 /* Fill GDB's register array with the floating-point register values in
 361    *FPREGSETP.  */
 362
 363 void
 364 supply_fpregset (elf_fpregset_t *fpregsetp)
 365 {
 366   int regi;
 367
 368   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 369     supply_register (regi, FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 370   supply_register (M68K_FPC_REGNUM, (char *) &fpregsetp->fpcntl[0]);
 371   supply_register (M68K_FPS_REGNUM, (char *) &fpregsetp->fpcntl[1]);
 372   supply_register (M68K_FPI_REGNUM, (char *) &fpregsetp->fpcntl[2]);
 373 }
 374
 375 /* Fill register REGNO (if it is a floating-point register) in
 376    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 377    do this for all registers.  */
 378
 379 void
 380 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 381 {
 382   int i;
 383
 384   /* Fill in the floating-point registers.  */
 385   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 386     if (regno == -1 || regno == i)
 387       regcache_collect (i, FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 388
 389   /* Fill in the floating-point control registers.  */
 390   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 391     if (regno == -1 || regno == i)
 392       regcache_collect (i, (char *) &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 393 }
 394
 395 #ifdef HAVE_PTRACE_GETREGS
 396
 397 /* Fetch all floating-point registers from process/thread TID and store
 398    thier values in GDB's register array.  */
 399
 400 static void
 401 fetch_fpregs (int tid)
 402 {
 403   elf_fpregset_t fpregs;
 404
 405   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 406     perror_with_name ("Couldn't get floating point status");
 407
 408   supply_fpregset (&fpregs);
 409 }
 410
 411 /* Store all valid floating-point registers in GDB's register array
 412    into the process/thread specified by TID.  */
 413
 414 static void
 415 store_fpregs (int tid, int regno)
 416 {
 417   elf_fpregset_t fpregs;
 418
 419   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 420     perror_with_name ("Couldn't get floating point status");
 421
 422   fill_fpregset (&fpregs, regno);
 423
 424   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 425     perror_with_name ("Couldn't write floating point status");
 426 }
 427
 428 #else
 429
 430 static void fetch_fpregs (int tid) {}
 431 static void store_fpregs (int tid, int regno) {}
 432
 433 #endif
 434
 435 #endif
 436 \f
 437 /* Transferring arbitrary registers between GDB and inferior.  */
 438
 439 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 440    this for all registers (including the floating point and SSE
 441    registers).  */
 442
 443 void
 444 fetch_inferior_registers (int regno)
 445 {
 446   int tid;
 447
 448   /* Use the old method of peeking around in `struct user' if the
 449      GETREGS request isn't available.  */
 450   if (! have_ptrace_getregs)
 451     {
 452       old_fetch_inferior_registers (regno);
 453       return;
 454     }
 455
 456   /* GNU/Linux LWP ID's are process ID's.  */
 457   tid = TIDGET (inferior_ptid);
 458   if (tid == 0)
 459     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 460
 461   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 462      transfers more registers in one system call, and we'll cache the
 463      results.  But remember that fetch_fpxregs can fail, and return
 464      zero.  */
 465   if (regno == -1)
 466     {
 467       fetch_regs (tid);
 468
 469       /* The call above might reset `have_ptrace_getregs'.  */
 470       if (! have_ptrace_getregs)
 471         {
 472           old_fetch_inferior_registers (-1);
 473           return;
 474         }
 475
 476       fetch_fpregs (tid);
 477       return;
 478     }
 479
 480   if (getregs_supplies (regno))
 481     {
 482       fetch_regs (tid);
 483       return;
 484     }
 485
 486   if (getfpregs_supplies (regno))
 487     {
 488       fetch_fpregs (tid);
 489       return;
 490     }
 491
 492   internal_error (__FILE__, __LINE__,
 493                   "Got request for bad register number %d.", regno);
 494 }
 495
 496 /* Store register REGNO back into the child process.  If REGNO is -1,
 497    do this for all registers (including the floating point and SSE
 498    registers).  */
 499 void
 500 store_inferior_registers (int regno)
 501 {
 502   int tid;
 503
 504   /* Use the old method of poking around in `struct user' if the
 505      SETREGS request isn't available.  */
 506   if (! have_ptrace_getregs)
 507     {
 508       old_store_inferior_registers (regno);
 509       return;
 510     }
 511
 512   /* GNU/Linux LWP ID's are process ID's.  */
 513   tid = TIDGET (inferior_ptid);
 514   if (tid == 0)
 515     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 516
 517   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 518      transfers more registers in one system call.  But remember that
 519      store_fpregs can fail, and return zero.  */
 520   if (regno == -1)
 521     {
 522       store_regs (tid, regno);
 523       store_fpregs (tid, regno);
 524       return;
 525     }
 526
 527   if (getregs_supplies (regno))
 528     {
 529       store_regs (tid, regno);
 530       return;
 531     }
 532
 533   if (getfpregs_supplies (regno))
 534     {
 535       store_fpregs (tid, regno);
 536       return;
 537     }
 538
 539   internal_error (__FILE__, __LINE__,
 540                   "Got request to store bad register number %d.", regno);
 541 }
 542 \f
 543 /* Interpreting register set info found in core files.  */
 544
 545 /* Provide registers to GDB from a core file.
 546
 547    (We can't use the generic version of this function in
 548    core-regset.c, because we need to use elf_gregset_t instead of
 549    gregset_t.)
 550
 551    CORE_REG_SECT points to an array of bytes, which are the contents
 552    of a `note' from a core file which BFD thinks might contain
 553    register contents.  CORE_REG_SIZE is its size.
 554
 555    WHICH says which register set corelow suspects this is:
 556      0 --- the general-purpose register set, in elf_gregset_t format
 557      2 --- the floating-point register set, in elf_fpregset_t format
 558
 559    REG_ADDR isn't used on GNU/Linux.  */
 560
 561 static void
 562 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size,
 563                       int which, CORE_ADDR reg_addr)
 564 {
 565   elf_gregset_t gregset;
 566   elf_fpregset_t fpregset;
 567
 568   switch (which)
 569     {
 570     case 0:
 571       if (core_reg_size != sizeof (gregset))
 572         warning ("Wrong size gregset in core file.");
 573       else
 574         {
 575           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 576           supply_gregset (&gregset);
 577         }
 578       break;
 579
 580     case 2:
 581       if (core_reg_size != sizeof (fpregset))
 582         warning ("Wrong size fpregset in core file.");
 583       else
 584         {
 585           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 586           supply_fpregset (&fpregset);
 587         }
 588       break;
 589
 590     default:
 591       /* We've covered all the kinds of registers we know about here,
 592          so this must be something we wouldn't know what to do with
 593          anyway.  Just ignore it.  */
 594       break;
 595     }
 596 }
 597 \f
 598
 599 int
 600 kernel_u_size (void)
 601 {
 602   return (sizeof (struct user));
 603 }
 604 \f
 605 /* Register that we are able to handle GNU/Linux ELF core file
 606    formats.  */
 607
 608 static struct core_fns linux_elf_core_fns =
 609 {
 610   bfd_target_elf_flavour,               /* core_flavour */
 611   default_check_format,                 /* check_format */
 612   default_core_sniffer,                 /* core_sniffer */
 613   fetch_core_registers,                 /* core_read_registers */
 614   NULL                                  /* next */
 615 };
 616
 617 void
 618 _initialize_m68k_linux_nat (void)
 619 {
 620   add_core_fns (&linux_elf_core_fns);
 621 }