gdb/m68klinux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright (C) 1996, 1998, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007,
   4    2008 Free Software Foundation, 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 3 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, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "frame.h"
  23 #include "inferior.h"
  24 #include "language.h"
  25 #include "gdbcore.h"
  26 #include "gdb_string.h"
  27 #include "regcache.h"
  28 #include "target.h"
  29 #include "linux-nat.h"
  30
  31 #include "m68k-tdep.h"
  32
  33 #include <sys/param.h>
  34 #include <sys/dir.h>
  35 #include <signal.h>
  36 #include <sys/ptrace.h>
  37 #include <sys/user.h>
  38 #include <sys/ioctl.h>
  39 #include <fcntl.h>
  40 #include <sys/procfs.h>
  41
  42 #ifdef HAVE_SYS_REG_H
  43 #include <sys/reg.h>
  44 #endif
  45
  46 #include <sys/file.h>
  47 #include "gdb_stat.h"
  48
  49 #include "floatformat.h"
  50
  51 #include "target.h"
  52
  53 /* Prototypes for supply_gregset etc. */
  54 #include "gregset.h"
  55 \f
  56 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  57 static const int regmap[] =
  58 {
  59   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  60   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  61   PT_SR, PT_PC,
  62   /* PT_FP0, ..., PT_FP7 */
  63   21, 24, 27, 30, 33, 36, 39, 42,
  64   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  65   45, 46, 47
  66 };
  67
  68 /* Which ptrace request retrieves which registers?
  69    These apply to the corresponding SET requests as well.  */
  70 #define NUM_GREGS (18)
  71 #define MAX_NUM_REGS (NUM_GREGS + 11)
  72
  73 int
  74 getregs_supplies (int regno)
  75 {
  76   return 0 <= regno && regno < NUM_GREGS;
  77 }
  78
  79 int
  80 getfpregs_supplies (int regno)
  81 {
  82   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  83 }
  84
  85 /* Does the current host support the GETREGS request?  */
  86 int have_ptrace_getregs =
  87 #ifdef HAVE_PTRACE_GETREGS
  88   1
  89 #else
  90   0
  91 #endif
  92 ;
  93
  94 \f
  95
  96 /* Fetching registers directly from the U area, one at a time.  */
  97
  98 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
  99    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 100    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 101    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 102    fall back on that code when GDB is running on top of a kernel that
 103    doesn't support the GETREGS request.  */
 104
 105 #ifndef PT_READ_U
 106 #define PT_READ_U PTRACE_PEEKUSR
 107 #endif
 108 #ifndef PT_WRITE_U
 109 #define PT_WRITE_U PTRACE_POKEUSR
 110 #endif
 111
 112 /* Fetch one register.  */
 113
 114 static void
 115 fetch_register (struct regcache *regcache, int regno)
 116 {
 117   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 118   /* This isn't really an address.  But ptrace thinks of it as one.  */
 119   CORE_ADDR regaddr;
 120   char mess[128];               /* For messages */
 121   int i;
 122   char buf[MAX_REGISTER_SIZE];
 123   int tid;
 124
 125   if (gdbarch_cannot_fetch_register (gdbarch, regno))
 126     {
 127       memset (buf, '\0', register_size (gdbarch, regno)); /* Supply zeroes */
 128       regcache_raw_supply (regcache, regno, buf);
 129       return;
 130     }
 131
 132   /* Overload thread id onto process id */
 133   tid = TIDGET (inferior_ptid);
 134   if (tid == 0)
 135     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 136
 137   regaddr = 4 * regmap[regno];
 138   for (i = 0; i < register_size (gdbarch, regno);
 139        i += sizeof (PTRACE_TYPE_RET))
 140     {
 141       errno = 0;
 142       *(PTRACE_TYPE_RET *) &buf[i] = ptrace (PT_READ_U, tid,
 143                                               (PTRACE_TYPE_ARG3) regaddr, 0);
 144       regaddr += sizeof (PTRACE_TYPE_RET);
 145       if (errno != 0)
 146         {
 147           sprintf (mess, "reading register %s (#%d)",
 148                    gdbarch_register_name (gdbarch, regno), regno);
 149           perror_with_name (mess);
 150         }
 151     }
 152   regcache_raw_supply (regcache, regno, buf);
 153 }
 154
 155 /* Fetch register values from the inferior.
 156    If REGNO is negative, do this for all registers.
 157    Otherwise, REGNO specifies which register (so we can save time). */
 158
 159 static void
 160 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 161 {
 162   if (regno >= 0)
 163     {
 164       fetch_register (regcache, regno);
 165     }
 166   else
 167     {
 168       for (regno = 0;
 169            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 170            regno++)
 171         {
 172           fetch_register (regcache, regno);
 173         }
 174     }
 175 }
 176
 177 /* Store one register. */
 178
 179 static void
 180 store_register (const struct regcache *regcache, int regno)
 181 {
 182   struct gdbarch *gdbarch = reg_regcache_arch (regcache);
 183   /* This isn't really an address.  But ptrace thinks of it as one.  */
 184   CORE_ADDR regaddr;
 185   char mess[128];               /* For messages */
 186   int i;
 187   int tid;
 188   char buf[MAX_REGISTER_SIZE];
 189
 190   if (gdbarch_cannot_store_register (gdbarch, regno))
 191     return;
 192
 193   /* Overload thread id onto process id */
 194   tid = TIDGET (inferior_ptid);
 195   if (tid == 0)
 196     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 197
 198   regaddr = 4 * regmap[regno];
 199
 200   /* Put the contents of regno into a local buffer */
 201   regcache_raw_collect (regcache, regno, buf);
 202
 203   /* Store the local buffer into the inferior a chunk at the time. */
 204   for (i = 0; i < register_size (gdbarch, regno);
 205        i += sizeof (PTRACE_TYPE_RET))
 206     {
 207       errno = 0;
 208       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 209               *(PTRACE_TYPE_RET *) (buf + i));
 210       regaddr += sizeof (PTRACE_TYPE_RET);
 211       if (errno != 0)
 212         {
 213           sprintf (mess, "writing register %s (#%d)",
 214                    gdbarch_register_name (gdbarch, regno), regno);
 215           perror_with_name (mess);
 216         }
 217     }
 218 }
 219
 220 /* Store our register values back into the inferior.
 221    If REGNO is negative, do this for all registers.
 222    Otherwise, REGNO specifies which register (so we can save time).  */
 223
 224 static void
 225 old_store_inferior_registers (const struct regcache *regcache, int regno)
 226 {
 227   if (regno >= 0)
 228     {
 229       store_register (regcache, regno);
 230     }
 231   else
 232     {
 233       for (regno = 0;
 234            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 235            regno++)
 236         {
 237           store_register (regcache, regno);
 238         }
 239     }
 240 }
 241 \f
 242 /*  Given a pointer to a general register set in /proc format
 243    (elf_gregset_t *), unpack the register contents and supply
 244    them as gdb's idea of the current register values. */
 245
 246 void
 247 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 248 {
 249   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 250   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 251   int regi;
 252
 253   for (regi = M68K_D0_REGNUM;
 254        regi <= gdbarch_sp_regnum (gdbarch);
 255        regi++)
 256     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 257   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 258                        &regp[PT_SR]);
 259   regcache_raw_supply (regcache,
 260                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 261 }
 262
 263 /* Fill register REGNO (if it is a general-purpose register) in
 264    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 265    do this for all registers.  */
 266 void
 267 fill_gregset (const struct regcache *regcache,
 268               elf_gregset_t *gregsetp, int regno)
 269 {
 270   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 271   int i;
 272
 273   for (i = 0; i < NUM_GREGS; i++)
 274     if (regno == -1 || regno == i)
 275       regcache_raw_collect (regcache, i, regp + regmap[i]);
 276 }
 277
 278 #ifdef HAVE_PTRACE_GETREGS
 279
 280 /* Fetch all general-purpose registers from process/thread TID and
 281    store their values in GDB's register array.  */
 282
 283 static void
 284 fetch_regs (struct regcache *regcache, int tid)
 285 {
 286   elf_gregset_t regs;
 287
 288   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 289     {
 290       if (errno == EIO)
 291         {
 292           /* The kernel we're running on doesn't support the GETREGS
 293              request.  Reset `have_ptrace_getregs'.  */
 294           have_ptrace_getregs = 0;
 295           return;
 296         }
 297
 298       perror_with_name (_("Couldn't get registers"));
 299     }
 300
 301   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 302 }
 303
 304 /* Store all valid general-purpose registers in GDB's register array
 305    into the process/thread specified by TID.  */
 306
 307 static void
 308 store_regs (const struct regcache *regcache, int tid, int regno)
 309 {
 310   elf_gregset_t regs;
 311
 312   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 313     perror_with_name (_("Couldn't get registers"));
 314
 315   fill_gregset (regcache, &regs, regno);
 316
 317   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 318     perror_with_name (_("Couldn't write registers"));
 319 }
 320
 321 #else
 322
 323 static void fetch_regs (struct regcache *regcache, int tid) {}
 324 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 325
 326 #endif
 327
 328 \f
 329 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 330
 331 /* What is the address of fpN within the floating-point register set F?  */
 332 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 333
 334 /* Fill GDB's register array with the floating-point register values in
 335    *FPREGSETP.  */
 336
 337 void
 338 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 339 {
 340   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 341   int regi;
 342
 343   for (regi = gdbarch_fp0_regnum (gdbarch);
 344        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 345     regcache_raw_supply (regcache, regi,
 346                          FPREG_ADDR (fpregsetp,
 347                                      regi - gdbarch_fp0_regnum (gdbarch)));
 348   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 349   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 350   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 351 }
 352
 353 /* Fill register REGNO (if it is a floating-point register) in
 354    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 355    do this for all registers.  */
 356
 357 void
 358 fill_fpregset (const struct regcache *regcache,
 359                elf_fpregset_t *fpregsetp, int regno)
 360 {
 361   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 362   int i;
 363
 364   /* Fill in the floating-point registers.  */
 365   for (i = gdbarch_fp0_regnum (gdbarch);
 366        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 367     if (regno == -1 || regno == i)
 368       regcache_raw_collect (regcache, i,
 369                             FPREG_ADDR (fpregsetp,
 370                                         i - gdbarch_fp0_regnum (gdbarch)));
 371
 372   /* Fill in the floating-point control registers.  */
 373   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 374     if (regno == -1 || regno == i)
 375       regcache_raw_collect (regcache, i,
 376                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 377 }
 378
 379 #ifdef HAVE_PTRACE_GETREGS
 380
 381 /* Fetch all floating-point registers from process/thread TID and store
 382    thier values in GDB's register array.  */
 383
 384 static void
 385 fetch_fpregs (struct regcache *regcache, int tid)
 386 {
 387   elf_fpregset_t fpregs;
 388
 389   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 390     perror_with_name (_("Couldn't get floating point status"));
 391
 392   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 393 }
 394
 395 /* Store all valid floating-point registers in GDB's register array
 396    into the process/thread specified by TID.  */
 397
 398 static void
 399 store_fpregs (const struct regcache *regcache, int tid, int regno)
 400 {
 401   elf_fpregset_t fpregs;
 402
 403   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 404     perror_with_name (_("Couldn't get floating point status"));
 405
 406   fill_fpregset (regcache, &fpregs, regno);
 407
 408   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 409     perror_with_name (_("Couldn't write floating point status"));
 410 }
 411
 412 #else
 413
 414 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 415 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 416
 417 #endif
 418 \f
 419 /* Transferring arbitrary registers between GDB and inferior.  */
 420
 421 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 422    this for all registers (including the floating point and SSE
 423    registers).  */
 424
 425 static void
 426 m68k_linux_fetch_inferior_registers (struct regcache *regcache, int regno)
 427 {
 428   int tid;
 429
 430   /* Use the old method of peeking around in `struct user' if the
 431      GETREGS request isn't available.  */
 432   if (! have_ptrace_getregs)
 433     {
 434       old_fetch_inferior_registers (regcache, regno);
 435       return;
 436     }
 437
 438   /* GNU/Linux LWP ID's are process ID's.  */
 439   tid = TIDGET (inferior_ptid);
 440   if (tid == 0)
 441     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 442
 443   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 444      transfers more registers in one system call, and we'll cache the
 445      results.  But remember that fetch_fpxregs can fail, and return
 446      zero.  */
 447   if (regno == -1)
 448     {
 449       fetch_regs (regcache, tid);
 450
 451       /* The call above might reset `have_ptrace_getregs'.  */
 452       if (! have_ptrace_getregs)
 453         {
 454           old_fetch_inferior_registers (regcache, -1);
 455           return;
 456         }
 457
 458       fetch_fpregs (regcache, tid);
 459       return;
 460     }
 461
 462   if (getregs_supplies (regno))
 463     {
 464       fetch_regs (regcache, tid);
 465       return;
 466     }
 467
 468   if (getfpregs_supplies (regno))
 469     {
 470       fetch_fpregs (regcache, tid);
 471       return;
 472     }
 473
 474   internal_error (__FILE__, __LINE__,
 475                   _("Got request for bad register number %d."), regno);
 476 }
 477
 478 /* Store register REGNO back into the child process.  If REGNO is -1,
 479    do this for all registers (including the floating point and SSE
 480    registers).  */
 481 static void
 482 m68k_linux_store_inferior_registers (struct regcache *regcache, int regno)
 483 {
 484   int tid;
 485
 486   /* Use the old method of poking around in `struct user' if the
 487      SETREGS request isn't available.  */
 488   if (! have_ptrace_getregs)
 489     {
 490       old_store_inferior_registers (regcache, regno);
 491       return;
 492     }
 493
 494   /* GNU/Linux LWP ID's are process ID's.  */
 495   tid = TIDGET (inferior_ptid);
 496   if (tid == 0)
 497     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 498
 499   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 500      transfers more registers in one system call.  But remember that
 501      store_fpregs can fail, and return zero.  */
 502   if (regno == -1)
 503     {
 504       store_regs (regcache, tid, regno);
 505       store_fpregs (regcache, tid, regno);
 506       return;
 507     }
 508
 509   if (getregs_supplies (regno))
 510     {
 511       store_regs (regcache, tid, regno);
 512       return;
 513     }
 514
 515   if (getfpregs_supplies (regno))
 516     {
 517       store_fpregs (regcache, tid, regno);
 518       return;
 519     }
 520
 521   internal_error (__FILE__, __LINE__,
 522                   _("Got request to store bad register number %d."), regno);
 523 }
 524 \f
 525 /* Interpreting register set info found in core files.  */
 526
 527 /* Provide registers to GDB from a core file.
 528
 529    (We can't use the generic version of this function in
 530    core-regset.c, because we need to use elf_gregset_t instead of
 531    gregset_t.)
 532
 533    CORE_REG_SECT points to an array of bytes, which are the contents
 534    of a `note' from a core file which BFD thinks might contain
 535    register contents.  CORE_REG_SIZE is its size.
 536
 537    WHICH says which register set corelow suspects this is:
 538      0 --- the general-purpose register set, in elf_gregset_t format
 539      2 --- the floating-point register set, in elf_fpregset_t format
 540
 541    REG_ADDR isn't used on GNU/Linux.  */
 542
 543 static void
 544 fetch_core_registers (struct regcache *regcache,
 545                       char *core_reg_sect, unsigned core_reg_size,
 546                       int which, CORE_ADDR reg_addr)
 547 {
 548   elf_gregset_t gregset;
 549   elf_fpregset_t fpregset;
 550
 551   switch (which)
 552     {
 553     case 0:
 554       if (core_reg_size != sizeof (gregset))
 555         warning (_("Wrong size gregset in core file."));
 556       else
 557         {
 558           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 559           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 560         }
 561       break;
 562
 563     case 2:
 564       if (core_reg_size != sizeof (fpregset))
 565         warning (_("Wrong size fpregset in core file."));
 566       else
 567         {
 568           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 569           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 570         }
 571       break;
 572
 573     default:
 574       /* We've covered all the kinds of registers we know about here,
 575          so this must be something we wouldn't know what to do with
 576          anyway.  Just ignore it.  */
 577       break;
 578     }
 579 }
 580 \f
 581
 582 /* Register that we are able to handle GNU/Linux ELF core file
 583    formats.  */
 584
 585 static struct core_fns linux_elf_core_fns =
 586 {
 587   bfd_target_elf_flavour,               /* core_flavour */
 588   default_check_format,                 /* check_format */
 589   default_core_sniffer,                 /* core_sniffer */
 590   fetch_core_registers,                 /* core_read_registers */
 591   NULL                                  /* next */
 592 };
 593
 594 void _initialize_m68k_linux_nat (void);
 595
 596 void
 597 _initialize_m68k_linux_nat (void)
 598 {
 599   struct target_ops *t;
 600
 601   /* Fill in the generic GNU/Linux methods.  */
 602   t = linux_target ();
 603
 604   /* Add our register access methods.  */
 605   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 606   t->to_store_registers = m68k_linux_store_inferior_registers;
 607
 608   /* Register the target.  */
 609   linux_nat_add_target (t);
 610
 611   deprecated_add_core_fns (&linux_elf_core_fns);
 612 }