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    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 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., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, 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 #include "target.h"
  31 #include "linux-nat.h"
  32
  33 #include "m68k-tdep.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/dir.h>
  37 #include <signal.h>
  38 #include <sys/ptrace.h>
  39 #include <sys/user.h>
  40 #include <sys/ioctl.h>
  41 #include <fcntl.h>
  42 #include <sys/procfs.h>
  43
  44 #ifdef HAVE_SYS_REG_H
  45 #include <sys/reg.h>
  46 #endif
  47
  48 #include <sys/file.h>
  49 #include "gdb_stat.h"
  50
  51 #include "floatformat.h"
  52
  53 #include "target.h"
  54
  55 /* Prototypes for supply_gregset etc. */
  56 #include "gregset.h"
  57 \f
  58 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  59 static const int regmap[] =
  60 {
  61   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  62   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  63   PT_SR, PT_PC,
  64   /* PT_FP0, ..., PT_FP7 */
  65   21, 24, 27, 30, 33, 36, 39, 42,
  66   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  67   45, 46, 47
  68 };
  69
  70 /* Which ptrace request retrieves which registers?
  71    These apply to the corresponding SET requests as well.  */
  72 #define NUM_GREGS (18)
  73 #define MAX_NUM_REGS (NUM_GREGS + 11)
  74
  75 int
  76 getregs_supplies (int regno)
  77 {
  78   return 0 <= regno && regno < NUM_GREGS;
  79 }
  80
  81 int
  82 getfpregs_supplies (int regno)
  83 {
  84   return gdbarch_fp0_regnum (current_gdbarch) <= regno
  85          && regno <= M68K_FPI_REGNUM;
  86 }
  87
  88 /* Does the current host support the GETREGS request?  */
  89 int have_ptrace_getregs =
  90 #ifdef HAVE_PTRACE_GETREGS
  91   1
  92 #else
  93   0
  94 #endif
  95 ;
  96
  97 \f
  98
  99 /* Fetching registers directly from the U area, one at a time.  */
 100
 101 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 102    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 103    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 104    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 105    fall back on that code when GDB is running on top of a kernel that
 106    doesn't support the GETREGS request.  */
 107
 108 #ifndef PT_READ_U
 109 #define PT_READ_U PTRACE_PEEKUSR
 110 #endif
 111 #ifndef PT_WRITE_U
 112 #define PT_WRITE_U PTRACE_POKEUSR
 113 #endif
 114
 115 /* Fetch one register.  */
 116
 117 static void
 118 fetch_register (struct regcache *regcache, int regno)
 119 {
 120   /* This isn't really an address.  But ptrace thinks of it as one.  */
 121   CORE_ADDR regaddr;
 122   char mess[128];               /* For messages */
 123   int i;
 124   char buf[MAX_REGISTER_SIZE];
 125   int tid;
 126
 127   if (gdbarch_cannot_fetch_register (current_gdbarch, regno))
 128     {
 129       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 130       regcache_raw_supply (regcache, regno, buf);
 131       return;
 132     }
 133
 134   /* Overload thread id onto process id */
 135   tid = TIDGET (inferior_ptid);
 136   if (tid == 0)
 137     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 138
 139   regaddr = 4 * regmap[regno];
 140   for (i = 0; i < register_size (current_gdbarch, regno);
 141        i += sizeof (PTRACE_TYPE_RET))
 142     {
 143       errno = 0;
 144       *(PTRACE_TYPE_RET *) &buf[i] = ptrace (PT_READ_U, tid,
 145                                               (PTRACE_TYPE_ARG3) regaddr, 0);
 146       regaddr += sizeof (PTRACE_TYPE_RET);
 147       if (errno != 0)
 148         {
 149           sprintf (mess, "reading register %s (#%d)",
 150                    gdbarch_register_name (current_gdbarch, regno), regno);
 151           perror_with_name (mess);
 152         }
 153     }
 154   regcache_raw_supply (regcache, regno, buf);
 155 }
 156
 157 /* Fetch register values from the inferior.
 158    If REGNO is negative, do this for all registers.
 159    Otherwise, REGNO specifies which register (so we can save time). */
 160
 161 static void
 162 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 163 {
 164   if (regno >= 0)
 165     {
 166       fetch_register (regcache, regno);
 167     }
 168   else
 169     {
 170       for (regno = 0; regno < gdbarch_num_regs (current_gdbarch); 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   /* This isn't really an address.  But ptrace thinks of it as one.  */
 183   CORE_ADDR regaddr;
 184   char mess[128];               /* For messages */
 185   int i;
 186   int tid;
 187   char buf[MAX_REGISTER_SIZE];
 188
 189   if (gdbarch_cannot_store_register (current_gdbarch, regno))
 190     return;
 191
 192   /* Overload thread id onto process id */
 193   tid = TIDGET (inferior_ptid);
 194   if (tid == 0)
 195     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 196
 197   regaddr = 4 * regmap[regno];
 198
 199   /* Put the contents of regno into a local buffer */
 200   regcache_raw_collect (regcache, regno, buf);
 201
 202   /* Store the local buffer into the inferior a chunk at the time. */
 203   for (i = 0; i < register_size (current_gdbarch, regno);
 204        i += sizeof (PTRACE_TYPE_RET))
 205     {
 206       errno = 0;
 207       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 208               *(PTRACE_TYPE_RET *) (buf + i));
 209       regaddr += sizeof (PTRACE_TYPE_RET);
 210       if (errno != 0)
 211         {
 212           sprintf (mess, "writing register %s (#%d)",
 213                    gdbarch_register_name (current_gdbarch, regno), regno);
 214           perror_with_name (mess);
 215         }
 216     }
 217 }
 218
 219 /* Store our register values back into the inferior.
 220    If REGNO is negative, do this for all registers.
 221    Otherwise, REGNO specifies which register (so we can save time).  */
 222
 223 static void
 224 old_store_inferior_registers (const struct regcache *regcache, int regno)
 225 {
 226   if (regno >= 0)
 227     {
 228       store_register (regcache, regno);
 229     }
 230   else
 231     {
 232       for (regno = 0; regno < gdbarch_num_regs (current_gdbarch); regno++)
 233         {
 234           store_register (regcache, regno);
 235         }
 236     }
 237 }
 238 \f
 239 /*  Given a pointer to a general register set in /proc format
 240    (elf_gregset_t *), unpack the register contents and supply
 241    them as gdb's idea of the current register values. */
 242
 243 void
 244 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 245 {
 246   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 247   int regi;
 248
 249   for (regi = M68K_D0_REGNUM;
 250        regi <= gdbarch_sp_regnum (current_gdbarch);
 251        regi++)
 252     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 253   regcache_raw_supply (regcache, gdbarch_ps_regnum (current_gdbarch),
 254                        &regp[PT_SR]);
 255   regcache_raw_supply (regcache,
 256                        gdbarch_pc_regnum (current_gdbarch), &regp[PT_PC]);
 257 }
 258
 259 /* Fill register REGNO (if it is a general-purpose register) in
 260    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 261    do this for all registers.  */
 262 void
 263 fill_gregset (const struct regcache *regcache,
 264               elf_gregset_t *gregsetp, int regno)
 265 {
 266   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 267   int i;
 268
 269   for (i = 0; i < NUM_GREGS; i++)
 270     if (regno == -1 || regno == i)
 271       regcache_raw_collect (regcache, i, regp + regmap[i]);
 272 }
 273
 274 #ifdef HAVE_PTRACE_GETREGS
 275
 276 /* Fetch all general-purpose registers from process/thread TID and
 277    store their values in GDB's register array.  */
 278
 279 static void
 280 fetch_regs (struct regcache *regcache, int tid)
 281 {
 282   elf_gregset_t regs;
 283
 284   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 285     {
 286       if (errno == EIO)
 287         {
 288           /* The kernel we're running on doesn't support the GETREGS
 289              request.  Reset `have_ptrace_getregs'.  */
 290           have_ptrace_getregs = 0;
 291           return;
 292         }
 293
 294       perror_with_name (_("Couldn't get registers"));
 295     }
 296
 297   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 298 }
 299
 300 /* Store all valid general-purpose registers in GDB's register array
 301    into the process/thread specified by TID.  */
 302
 303 static void
 304 store_regs (const struct regcache *regcache, int tid, int regno)
 305 {
 306   elf_gregset_t regs;
 307
 308   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 309     perror_with_name (_("Couldn't get registers"));
 310
 311   fill_gregset (regcache, &regs, regno);
 312
 313   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 314     perror_with_name (_("Couldn't write registers"));
 315 }
 316
 317 #else
 318
 319 static void fetch_regs (struct regcache *regcache, int tid) {}
 320 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 321
 322 #endif
 323
 324 \f
 325 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 326
 327 /* What is the address of fpN within the floating-point register set F?  */
 328 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 329
 330 /* Fill GDB's register array with the floating-point register values in
 331    *FPREGSETP.  */
 332
 333 void
 334 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 335 {
 336   int regi;
 337
 338   for (regi = gdbarch_fp0_regnum (current_gdbarch);
 339        regi < gdbarch_fp0_regnum (current_gdbarch) + 8; regi++)
 340     regcache_raw_supply (regcache, regi,
 341                          FPREG_ADDR (fpregsetp,
 342                                      regi - gdbarch_fp0_regnum
 343                                             (current_gdbarch)));
 344   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 345   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 346   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 347 }
 348
 349 /* Fill register REGNO (if it is a floating-point register) in
 350    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 351    do this for all registers.  */
 352
 353 void
 354 fill_fpregset (const struct regcache *regcache,
 355                elf_fpregset_t *fpregsetp, int regno)
 356 {
 357   int i;
 358
 359   /* Fill in the floating-point registers.  */
 360   for (i = gdbarch_fp0_regnum (current_gdbarch);
 361        i < gdbarch_fp0_regnum (current_gdbarch) + 8; i++)
 362     if (regno == -1 || regno == i)
 363       regcache_raw_collect (regcache, i,
 364                             FPREG_ADDR (fpregsetp,
 365                                         i - gdbarch_fp0_regnum
 366                                             (current_gdbarch)));
 367
 368   /* Fill in the floating-point control registers.  */
 369   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 370     if (regno == -1 || regno == i)
 371       regcache_raw_collect (regcache, i,
 372                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 373 }
 374
 375 #ifdef HAVE_PTRACE_GETREGS
 376
 377 /* Fetch all floating-point registers from process/thread TID and store
 378    thier values in GDB's register array.  */
 379
 380 static void
 381 fetch_fpregs (struct regcache *regcache, int tid)
 382 {
 383   elf_fpregset_t fpregs;
 384
 385   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 386     perror_with_name (_("Couldn't get floating point status"));
 387
 388   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 389 }
 390
 391 /* Store all valid floating-point registers in GDB's register array
 392    into the process/thread specified by TID.  */
 393
 394 static void
 395 store_fpregs (const struct regcache *regcache, int tid, int regno)
 396 {
 397   elf_fpregset_t fpregs;
 398
 399   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 400     perror_with_name (_("Couldn't get floating point status"));
 401
 402   fill_fpregset (regcache, &fpregs, regno);
 403
 404   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 405     perror_with_name (_("Couldn't write floating point status"));
 406 }
 407
 408 #else
 409
 410 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 411 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 412
 413 #endif
 414 \f
 415 /* Transferring arbitrary registers between GDB and inferior.  */
 416
 417 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 418    this for all registers (including the floating point and SSE
 419    registers).  */
 420
 421 static void
 422 m68k_linux_fetch_inferior_registers (struct regcache *regcache, int regno)
 423 {
 424   int tid;
 425
 426   /* Use the old method of peeking around in `struct user' if the
 427      GETREGS request isn't available.  */
 428   if (! have_ptrace_getregs)
 429     {
 430       old_fetch_inferior_registers (regcache, regno);
 431       return;
 432     }
 433
 434   /* GNU/Linux LWP ID's are process ID's.  */
 435   tid = TIDGET (inferior_ptid);
 436   if (tid == 0)
 437     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 438
 439   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 440      transfers more registers in one system call, and we'll cache the
 441      results.  But remember that fetch_fpxregs can fail, and return
 442      zero.  */
 443   if (regno == -1)
 444     {
 445       fetch_regs (regcache, tid);
 446
 447       /* The call above might reset `have_ptrace_getregs'.  */
 448       if (! have_ptrace_getregs)
 449         {
 450           old_fetch_inferior_registers (regcache, -1);
 451           return;
 452         }
 453
 454       fetch_fpregs (regcache, tid);
 455       return;
 456     }
 457
 458   if (getregs_supplies (regno))
 459     {
 460       fetch_regs (regcache, tid);
 461       return;
 462     }
 463
 464   if (getfpregs_supplies (regno))
 465     {
 466       fetch_fpregs (regcache, tid);
 467       return;
 468     }
 469
 470   internal_error (__FILE__, __LINE__,
 471                   _("Got request for bad register number %d."), regno);
 472 }
 473
 474 /* Store register REGNO back into the child process.  If REGNO is -1,
 475    do this for all registers (including the floating point and SSE
 476    registers).  */
 477 static void
 478 m68k_linux_store_inferior_registers (struct regcache *regcache, int regno)
 479 {
 480   int tid;
 481
 482   /* Use the old method of poking around in `struct user' if the
 483      SETREGS request isn't available.  */
 484   if (! have_ptrace_getregs)
 485     {
 486       old_store_inferior_registers (regcache, regno);
 487       return;
 488     }
 489
 490   /* GNU/Linux LWP ID's are process ID's.  */
 491   tid = TIDGET (inferior_ptid);
 492   if (tid == 0)
 493     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 494
 495   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 496      transfers more registers in one system call.  But remember that
 497      store_fpregs can fail, and return zero.  */
 498   if (regno == -1)
 499     {
 500       store_regs (regcache, tid, regno);
 501       store_fpregs (regcache, tid, regno);
 502       return;
 503     }
 504
 505   if (getregs_supplies (regno))
 506     {
 507       store_regs (regcache, tid, regno);
 508       return;
 509     }
 510
 511   if (getfpregs_supplies (regno))
 512     {
 513       store_fpregs (regcache, tid, regno);
 514       return;
 515     }
 516
 517   internal_error (__FILE__, __LINE__,
 518                   _("Got request to store bad register number %d."), regno);
 519 }
 520 \f
 521 /* Interpreting register set info found in core files.  */
 522
 523 /* Provide registers to GDB from a core file.
 524
 525    (We can't use the generic version of this function in
 526    core-regset.c, because we need to use elf_gregset_t instead of
 527    gregset_t.)
 528
 529    CORE_REG_SECT points to an array of bytes, which are the contents
 530    of a `note' from a core file which BFD thinks might contain
 531    register contents.  CORE_REG_SIZE is its size.
 532
 533    WHICH says which register set corelow suspects this is:
 534      0 --- the general-purpose register set, in elf_gregset_t format
 535      2 --- the floating-point register set, in elf_fpregset_t format
 536
 537    REG_ADDR isn't used on GNU/Linux.  */
 538
 539 static void
 540 fetch_core_registers (struct regcache *regcache,
 541                       char *core_reg_sect, unsigned core_reg_size,
 542                       int which, CORE_ADDR reg_addr)
 543 {
 544   elf_gregset_t gregset;
 545   elf_fpregset_t fpregset;
 546
 547   switch (which)
 548     {
 549     case 0:
 550       if (core_reg_size != sizeof (gregset))
 551         warning (_("Wrong size gregset in core file."));
 552       else
 553         {
 554           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 555           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 556         }
 557       break;
 558
 559     case 2:
 560       if (core_reg_size != sizeof (fpregset))
 561         warning (_("Wrong size fpregset in core file."));
 562       else
 563         {
 564           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 565           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 566         }
 567       break;
 568
 569     default:
 570       /* We've covered all the kinds of registers we know about here,
 571          so this must be something we wouldn't know what to do with
 572          anyway.  Just ignore it.  */
 573       break;
 574     }
 575 }
 576 \f
 577
 578 /* Register that we are able to handle GNU/Linux ELF core file
 579    formats.  */
 580
 581 static struct core_fns linux_elf_core_fns =
 582 {
 583   bfd_target_elf_flavour,               /* core_flavour */
 584   default_check_format,                 /* check_format */
 585   default_core_sniffer,                 /* core_sniffer */
 586   fetch_core_registers,                 /* core_read_registers */
 587   NULL                                  /* next */
 588 };
 589
 590 void _initialize_m68k_linux_nat (void);
 591
 592 void
 593 _initialize_m68k_linux_nat (void)
 594 {
 595   struct target_ops *t;
 596
 597   /* Fill in the generic GNU/Linux methods.  */
 598   t = linux_target ();
 599
 600   /* Add our register access methods.  */
 601   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 602   t->to_store_registers = m68k_linux_store_inferior_registers;
 603
 604   /* Register the target.  */
 605   linux_nat_add_target (t);
 606
 607   deprecated_add_core_fns (&linux_elf_core_fns);
 608 }