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 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 gdbarch_fp0_regnum (current_gdbarch) <= regno
  83          && 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 /* Fetching registers directly from the U area, one at a time.  */
  98
  99 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 100    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 101    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 102    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 103    fall back on that code when GDB is running on top of a kernel that
 104    doesn't support the GETREGS request.  */
 105
 106 #ifndef PT_READ_U
 107 #define PT_READ_U PTRACE_PEEKUSR
 108 #endif
 109 #ifndef PT_WRITE_U
 110 #define PT_WRITE_U PTRACE_POKEUSR
 111 #endif
 112
 113 /* Fetch one register.  */
 114
 115 static void
 116 fetch_register (struct regcache *regcache, int regno)
 117 {
 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 (current_gdbarch, regno))
 126     {
 127       memset (buf, '\0', register_size (current_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 (current_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 (current_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; regno < gdbarch_num_regs (current_gdbarch); regno++)
 169         {
 170           fetch_register (regcache, regno);
 171         }
 172     }
 173 }
 174
 175 /* Store one register. */
 176
 177 static void
 178 store_register (const struct regcache *regcache, int regno)
 179 {
 180   /* This isn't really an address.  But ptrace thinks of it as one.  */
 181   CORE_ADDR regaddr;
 182   char mess[128];               /* For messages */
 183   int i;
 184   int tid;
 185   char buf[MAX_REGISTER_SIZE];
 186
 187   if (gdbarch_cannot_store_register (current_gdbarch, regno))
 188     return;
 189
 190   /* Overload thread id onto process id */
 191   tid = TIDGET (inferior_ptid);
 192   if (tid == 0)
 193     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 194
 195   regaddr = 4 * regmap[regno];
 196
 197   /* Put the contents of regno into a local buffer */
 198   regcache_raw_collect (regcache, regno, buf);
 199
 200   /* Store the local buffer into the inferior a chunk at the time. */
 201   for (i = 0; i < register_size (current_gdbarch, regno);
 202        i += sizeof (PTRACE_TYPE_RET))
 203     {
 204       errno = 0;
 205       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 206               *(PTRACE_TYPE_RET *) (buf + i));
 207       regaddr += sizeof (PTRACE_TYPE_RET);
 208       if (errno != 0)
 209         {
 210           sprintf (mess, "writing register %s (#%d)",
 211                    gdbarch_register_name (current_gdbarch, regno), regno);
 212           perror_with_name (mess);
 213         }
 214     }
 215 }
 216
 217 /* Store our register values back into the inferior.
 218    If REGNO is negative, do this for all registers.
 219    Otherwise, REGNO specifies which register (so we can save time).  */
 220
 221 static void
 222 old_store_inferior_registers (const struct regcache *regcache, int regno)
 223 {
 224   if (regno >= 0)
 225     {
 226       store_register (regcache, regno);
 227     }
 228   else
 229     {
 230       for (regno = 0; regno < gdbarch_num_regs (current_gdbarch); regno++)
 231         {
 232           store_register (regcache, regno);
 233         }
 234     }
 235 }
 236 \f
 237 /*  Given a pointer to a general register set in /proc format
 238    (elf_gregset_t *), unpack the register contents and supply
 239    them as gdb's idea of the current register values. */
 240
 241 void
 242 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 243 {
 244   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 245   int regi;
 246
 247   for (regi = M68K_D0_REGNUM;
 248        regi <= gdbarch_sp_regnum (current_gdbarch);
 249        regi++)
 250     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 251   regcache_raw_supply (regcache, gdbarch_ps_regnum (current_gdbarch),
 252                        &regp[PT_SR]);
 253   regcache_raw_supply (regcache,
 254                        gdbarch_pc_regnum (current_gdbarch), &regp[PT_PC]);
 255 }
 256
 257 /* Fill register REGNO (if it is a general-purpose register) in
 258    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 259    do this for all registers.  */
 260 void
 261 fill_gregset (const struct regcache *regcache,
 262               elf_gregset_t *gregsetp, int regno)
 263 {
 264   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 265   int i;
 266
 267   for (i = 0; i < NUM_GREGS; i++)
 268     if (regno == -1 || regno == i)
 269       regcache_raw_collect (regcache, i, regp + regmap[i]);
 270 }
 271
 272 #ifdef HAVE_PTRACE_GETREGS
 273
 274 /* Fetch all general-purpose registers from process/thread TID and
 275    store their values in GDB's register array.  */
 276
 277 static void
 278 fetch_regs (struct regcache *regcache, int tid)
 279 {
 280   elf_gregset_t regs;
 281
 282   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 283     {
 284       if (errno == EIO)
 285         {
 286           /* The kernel we're running on doesn't support the GETREGS
 287              request.  Reset `have_ptrace_getregs'.  */
 288           have_ptrace_getregs = 0;
 289           return;
 290         }
 291
 292       perror_with_name (_("Couldn't get registers"));
 293     }
 294
 295   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 296 }
 297
 298 /* Store all valid general-purpose registers in GDB's register array
 299    into the process/thread specified by TID.  */
 300
 301 static void
 302 store_regs (const struct regcache *regcache, int tid, int regno)
 303 {
 304   elf_gregset_t regs;
 305
 306   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 307     perror_with_name (_("Couldn't get registers"));
 308
 309   fill_gregset (regcache, &regs, regno);
 310
 311   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 312     perror_with_name (_("Couldn't write registers"));
 313 }
 314
 315 #else
 316
 317 static void fetch_regs (struct regcache *regcache, int tid) {}
 318 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 319
 320 #endif
 321
 322 \f
 323 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 324
 325 /* What is the address of fpN within the floating-point register set F?  */
 326 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 327
 328 /* Fill GDB's register array with the floating-point register values in
 329    *FPREGSETP.  */
 330
 331 void
 332 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 333 {
 334   int regi;
 335
 336   for (regi = gdbarch_fp0_regnum (current_gdbarch);
 337        regi < gdbarch_fp0_regnum (current_gdbarch) + 8; regi++)
 338     regcache_raw_supply (regcache, regi,
 339                          FPREG_ADDR (fpregsetp,
 340                                      regi - gdbarch_fp0_regnum
 341                                             (current_gdbarch)));
 342   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 343   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 344   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 345 }
 346
 347 /* Fill register REGNO (if it is a floating-point register) in
 348    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 349    do this for all registers.  */
 350
 351 void
 352 fill_fpregset (const struct regcache *regcache,
 353                elf_fpregset_t *fpregsetp, int regno)
 354 {
 355   int i;
 356
 357   /* Fill in the floating-point registers.  */
 358   for (i = gdbarch_fp0_regnum (current_gdbarch);
 359        i < gdbarch_fp0_regnum (current_gdbarch) + 8; i++)
 360     if (regno == -1 || regno == i)
 361       regcache_raw_collect (regcache, i,
 362                             FPREG_ADDR (fpregsetp,
 363                                         i - gdbarch_fp0_regnum
 364                                             (current_gdbarch)));
 365
 366   /* Fill in the floating-point control registers.  */
 367   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 368     if (regno == -1 || regno == i)
 369       regcache_raw_collect (regcache, i,
 370                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 371 }
 372
 373 #ifdef HAVE_PTRACE_GETREGS
 374
 375 /* Fetch all floating-point registers from process/thread TID and store
 376    thier values in GDB's register array.  */
 377
 378 static void
 379 fetch_fpregs (struct regcache *regcache, int tid)
 380 {
 381   elf_fpregset_t fpregs;
 382
 383   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 384     perror_with_name (_("Couldn't get floating point status"));
 385
 386   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 387 }
 388
 389 /* Store all valid floating-point registers in GDB's register array
 390    into the process/thread specified by TID.  */
 391
 392 static void
 393 store_fpregs (const struct regcache *regcache, int tid, int regno)
 394 {
 395   elf_fpregset_t fpregs;
 396
 397   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 398     perror_with_name (_("Couldn't get floating point status"));
 399
 400   fill_fpregset (regcache, &fpregs, regno);
 401
 402   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 403     perror_with_name (_("Couldn't write floating point status"));
 404 }
 405
 406 #else
 407
 408 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 409 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 410
 411 #endif
 412 \f
 413 /* Transferring arbitrary registers between GDB and inferior.  */
 414
 415 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 416    this for all registers (including the floating point and SSE
 417    registers).  */
 418
 419 static void
 420 m68k_linux_fetch_inferior_registers (struct regcache *regcache, int regno)
 421 {
 422   int tid;
 423
 424   /* Use the old method of peeking around in `struct user' if the
 425      GETREGS request isn't available.  */
 426   if (! have_ptrace_getregs)
 427     {
 428       old_fetch_inferior_registers (regcache, regno);
 429       return;
 430     }
 431
 432   /* GNU/Linux LWP ID's are process ID's.  */
 433   tid = TIDGET (inferior_ptid);
 434   if (tid == 0)
 435     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 436
 437   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 438      transfers more registers in one system call, and we'll cache the
 439      results.  But remember that fetch_fpxregs can fail, and return
 440      zero.  */
 441   if (regno == -1)
 442     {
 443       fetch_regs (regcache, tid);
 444
 445       /* The call above might reset `have_ptrace_getregs'.  */
 446       if (! have_ptrace_getregs)
 447         {
 448           old_fetch_inferior_registers (regcache, -1);
 449           return;
 450         }
 451
 452       fetch_fpregs (regcache, tid);
 453       return;
 454     }
 455
 456   if (getregs_supplies (regno))
 457     {
 458       fetch_regs (regcache, tid);
 459       return;
 460     }
 461
 462   if (getfpregs_supplies (regno))
 463     {
 464       fetch_fpregs (regcache, tid);
 465       return;
 466     }
 467
 468   internal_error (__FILE__, __LINE__,
 469                   _("Got request for bad register number %d."), regno);
 470 }
 471
 472 /* Store register REGNO back into the child process.  If REGNO is -1,
 473    do this for all registers (including the floating point and SSE
 474    registers).  */
 475 static void
 476 m68k_linux_store_inferior_registers (struct regcache *regcache, int regno)
 477 {
 478   int tid;
 479
 480   /* Use the old method of poking around in `struct user' if the
 481      SETREGS request isn't available.  */
 482   if (! have_ptrace_getregs)
 483     {
 484       old_store_inferior_registers (regcache, regno);
 485       return;
 486     }
 487
 488   /* GNU/Linux LWP ID's are process ID's.  */
 489   tid = TIDGET (inferior_ptid);
 490   if (tid == 0)
 491     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 492
 493   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 494      transfers more registers in one system call.  But remember that
 495      store_fpregs can fail, and return zero.  */
 496   if (regno == -1)
 497     {
 498       store_regs (regcache, tid, regno);
 499       store_fpregs (regcache, tid, regno);
 500       return;
 501     }
 502
 503   if (getregs_supplies (regno))
 504     {
 505       store_regs (regcache, tid, regno);
 506       return;
 507     }
 508
 509   if (getfpregs_supplies (regno))
 510     {
 511       store_fpregs (regcache, tid, regno);
 512       return;
 513     }
 514
 515   internal_error (__FILE__, __LINE__,
 516                   _("Got request to store bad register number %d."), regno);
 517 }
 518 \f
 519 /* Interpreting register set info found in core files.  */
 520
 521 /* Provide registers to GDB from a core file.
 522
 523    (We can't use the generic version of this function in
 524    core-regset.c, because we need to use elf_gregset_t instead of
 525    gregset_t.)
 526
 527    CORE_REG_SECT points to an array of bytes, which are the contents
 528    of a `note' from a core file which BFD thinks might contain
 529    register contents.  CORE_REG_SIZE is its size.
 530
 531    WHICH says which register set corelow suspects this is:
 532      0 --- the general-purpose register set, in elf_gregset_t format
 533      2 --- the floating-point register set, in elf_fpregset_t format
 534
 535    REG_ADDR isn't used on GNU/Linux.  */
 536
 537 static void
 538 fetch_core_registers (struct regcache *regcache,
 539                       char *core_reg_sect, unsigned core_reg_size,
 540                       int which, CORE_ADDR reg_addr)
 541 {
 542   elf_gregset_t gregset;
 543   elf_fpregset_t fpregset;
 544
 545   switch (which)
 546     {
 547     case 0:
 548       if (core_reg_size != sizeof (gregset))
 549         warning (_("Wrong size gregset in core file."));
 550       else
 551         {
 552           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 553           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 554         }
 555       break;
 556
 557     case 2:
 558       if (core_reg_size != sizeof (fpregset))
 559         warning (_("Wrong size fpregset in core file."));
 560       else
 561         {
 562           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 563           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 564         }
 565       break;
 566
 567     default:
 568       /* We've covered all the kinds of registers we know about here,
 569          so this must be something we wouldn't know what to do with
 570          anyway.  Just ignore it.  */
 571       break;
 572     }
 573 }
 574 \f
 575
 576 /* Register that we are able to handle GNU/Linux ELF core file
 577    formats.  */
 578
 579 static struct core_fns linux_elf_core_fns =
 580 {
 581   bfd_target_elf_flavour,               /* core_flavour */
 582   default_check_format,                 /* check_format */
 583   default_core_sniffer,                 /* core_sniffer */
 584   fetch_core_registers,                 /* core_read_registers */
 585   NULL                                  /* next */
 586 };
 587
 588 void _initialize_m68k_linux_nat (void);
 589
 590 void
 591 _initialize_m68k_linux_nat (void)
 592 {
 593   struct target_ops *t;
 594
 595   /* Fill in the generic GNU/Linux methods.  */
 596   t = linux_target ();
 597
 598   /* Add our register access methods.  */
 599   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 600   t->to_store_registers = m68k_linux_store_inferior_registers;
 601
 602   /* Register the target.  */
 603   linux_nat_add_target (t);
 604
 605   deprecated_add_core_fns (&linux_elf_core_fns);
 606 }