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 \f
  55 /* This table must line up with REGISTER_NAME in "m68k-tdep.c".  */
  56 static const int regmap[] =
  57 {
  58   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  59   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  60   PT_SR, PT_PC,
  61   /* PT_FP0, ..., PT_FP7 */
  62   21, 24, 27, 30, 33, 36, 39, 42,
  63   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  64   45, 46, 47
  65 };
  66
  67 /* Which ptrace request retrieves which registers?
  68    These apply to the corresponding SET requests as well.  */
  69 #define NUM_GREGS (18)
  70 #define MAX_NUM_REGS (NUM_GREGS + 11)
  71
  72 int
  73 getregs_supplies (int regno)
  74 {
  75   return 0 <= regno && regno < NUM_GREGS;
  76 }
  77
  78 int
  79 getfpregs_supplies (int regno)
  80 {
  81   return FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  82 }
  83
  84 /* Does the current host support the GETREGS request?  */
  85 int have_ptrace_getregs =
  86 #ifdef HAVE_PTRACE_GETREGS
  87   1
  88 #else
  89   0
  90 #endif
  91 ;
  92
  93 \f
  94
  95 /* Fetching registers directly from the U area, one at a time.  */
  96
  97 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
  98    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
  99    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 100    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 101    fall back on that code when GDB is running on top of a kernel that
 102    doesn't support the GETREGS request.  */
 103
 104 #ifndef PT_READ_U
 105 #define PT_READ_U PTRACE_PEEKUSR
 106 #endif
 107 #ifndef PT_WRITE_U
 108 #define PT_WRITE_U PTRACE_POKEUSR
 109 #endif
 110
 111 /* Fetch one register.  */
 112
 113 static void
 114 fetch_register (int regno)
 115 {
 116   /* This isn't really an address.  But ptrace thinks of it as one.  */
 117   CORE_ADDR regaddr;
 118   char mess[128];               /* For messages */
 119   int i;
 120   char buf[MAX_REGISTER_SIZE];
 121   int tid;
 122
 123   if (CANNOT_FETCH_REGISTER (regno))
 124     {
 125       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 126       regcache_raw_supply (current_regcache, regno, buf);
 127       return;
 128     }
 129
 130   /* Overload thread id onto process id */
 131   tid = TIDGET (inferior_ptid);
 132   if (tid == 0)
 133     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 134
 135   regaddr = 4 * regmap[regno];
 136   for (i = 0; i < register_size (current_gdbarch, regno);
 137        i += sizeof (PTRACE_TYPE_RET))
 138     {
 139       errno = 0;
 140       *(PTRACE_TYPE_RET *) &buf[i] = ptrace (PT_READ_U, tid,
 141                                               (PTRACE_TYPE_ARG3) regaddr, 0);
 142       regaddr += sizeof (PTRACE_TYPE_RET);
 143       if (errno != 0)
 144         {
 145           sprintf (mess, "reading register %s (#%d)",
 146                    REGISTER_NAME (regno), regno);
 147           perror_with_name (mess);
 148         }
 149     }
 150   regcache_raw_supply (current_regcache, regno, buf);
 151 }
 152
 153 /* Fetch register values from the inferior.
 154    If REGNO is negative, do this for all registers.
 155    Otherwise, REGNO specifies which register (so we can save time). */
 156
 157 static void
 158 old_fetch_inferior_registers (int regno)
 159 {
 160   if (regno >= 0)
 161     {
 162       fetch_register (regno);
 163     }
 164   else
 165     {
 166       for (regno = 0; regno < NUM_REGS; regno++)
 167         {
 168           fetch_register (regno);
 169         }
 170     }
 171 }
 172
 173 /* Store one register. */
 174
 175 static void
 176 store_register (int regno)
 177 {
 178   /* This isn't really an address.  But ptrace thinks of it as one.  */
 179   CORE_ADDR regaddr;
 180   char mess[128];               /* For messages */
 181   int i;
 182   int tid;
 183   char buf[MAX_REGISTER_SIZE];
 184
 185   if (CANNOT_STORE_REGISTER (regno))
 186     {
 187       return;
 188     }
 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 (current_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                    REGISTER_NAME (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 (int regno)
 223 {
 224   if (regno >= 0)
 225     {
 226       store_register (regno);
 227     }
 228   else
 229     {
 230       for (regno = 0; regno < NUM_REGS; regno++)
 231         {
 232           store_register (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
 242 /* Note both m68k-tdep.c and m68klinux-nat.c contain definitions
 243    for supply_gregset and supply_fpregset. The definitions
 244    in m68k-tdep.c are valid if USE_PROC_FS is defined. Otherwise,
 245    the definitions in m68klinux-nat.c will be used. This is a
 246    bit of a hack. The supply_* routines do not belong in
 247    *_tdep.c files. But, there are several lynx ports that currently
 248    depend on these definitions. */
 249
 250 #ifndef USE_PROC_FS
 251
 252 /* Prototypes for supply_gregset etc. */
 253 #include "gregset.h"
 254
 255 void
 256 supply_gregset (elf_gregset_t *gregsetp)
 257 {
 258   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 259   int regi;
 260
 261   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 262     regcache_raw_supply (current_regcache, regi, (char *) &regp[regmap[regi]]);
 263   regcache_raw_supply (current_regcache, PS_REGNUM, (char *) &regp[PT_SR]);
 264   regcache_raw_supply (current_regcache, PC_REGNUM, (char *) &regp[PT_PC]);
 265 }
 266
 267 /* Fill register REGNO (if it is a general-purpose register) in
 268    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 269    do this for all registers.  */
 270 void
 271 fill_gregset (elf_gregset_t *gregsetp, int regno)
 272 {
 273   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 274   int i;
 275
 276   for (i = 0; i < NUM_GREGS; i++)
 277     if (regno == -1 || regno == i)
 278       regcache_raw_collect (current_regcache, i, regp + regmap[i]);
 279 }
 280
 281 #ifdef HAVE_PTRACE_GETREGS
 282
 283 /* Fetch all general-purpose registers from process/thread TID and
 284    store their values in GDB's register array.  */
 285
 286 static void
 287 fetch_regs (int tid)
 288 {
 289   elf_gregset_t regs;
 290
 291   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 292     {
 293       if (errno == EIO)
 294         {
 295           /* The kernel we're running on doesn't support the GETREGS
 296              request.  Reset `have_ptrace_getregs'.  */
 297           have_ptrace_getregs = 0;
 298           return;
 299         }
 300
 301       perror_with_name (_("Couldn't get registers"));
 302     }
 303
 304   supply_gregset (&regs);
 305 }
 306
 307 /* Store all valid general-purpose registers in GDB's register array
 308    into the process/thread specified by TID.  */
 309
 310 static void
 311 store_regs (int tid, int regno)
 312 {
 313   elf_gregset_t regs;
 314
 315   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 316     perror_with_name (_("Couldn't get registers"));
 317
 318   fill_gregset (&regs, regno);
 319
 320   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 321     perror_with_name (_("Couldn't write registers"));
 322 }
 323
 324 #else
 325
 326 static void fetch_regs (int tid) {}
 327 static void store_regs (int tid, int regno) {}
 328
 329 #endif
 330
 331 \f
 332 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 333
 334 /* What is the address of fpN within the floating-point register set F?  */
 335 #define FPREG_ADDR(f, n) ((char *) &(f)->fpregs[(n) * 3])
 336
 337 /* Fill GDB's register array with the floating-point register values in
 338    *FPREGSETP.  */
 339
 340 void
 341 supply_fpregset (elf_fpregset_t *fpregsetp)
 342 {
 343   int regi;
 344
 345   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 346     regcache_raw_supply (current_regcache, regi,
 347                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 348   regcache_raw_supply (current_regcache, M68K_FPC_REGNUM,
 349                        (char *) &fpregsetp->fpcntl[0]);
 350   regcache_raw_supply (current_regcache, M68K_FPS_REGNUM,
 351                        (char *) &fpregsetp->fpcntl[1]);
 352   regcache_raw_supply (current_regcache, M68K_FPI_REGNUM,
 353                        (char *) &fpregsetp->fpcntl[2]);
 354 }
 355
 356 /* Fill register REGNO (if it is a floating-point register) in
 357    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 358    do this for all registers.  */
 359
 360 void
 361 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 362 {
 363   int i;
 364
 365   /* Fill in the floating-point registers.  */
 366   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 367     if (regno == -1 || regno == i)
 368       regcache_raw_collect (current_regcache, i,
 369                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 370
 371   /* Fill in the floating-point control registers.  */
 372   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 373     if (regno == -1 || regno == i)
 374       regcache_raw_collect (current_regcache, i,
 375                             (char *) &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 376 }
 377
 378 #ifdef HAVE_PTRACE_GETREGS
 379
 380 /* Fetch all floating-point registers from process/thread TID and store
 381    thier values in GDB's register array.  */
 382
 383 static void
 384 fetch_fpregs (int tid)
 385 {
 386   elf_fpregset_t fpregs;
 387
 388   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 389     perror_with_name (_("Couldn't get floating point status"));
 390
 391   supply_fpregset (&fpregs);
 392 }
 393
 394 /* Store all valid floating-point registers in GDB's register array
 395    into the process/thread specified by TID.  */
 396
 397 static void
 398 store_fpregs (int tid, int regno)
 399 {
 400   elf_fpregset_t fpregs;
 401
 402   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 403     perror_with_name (_("Couldn't get floating point status"));
 404
 405   fill_fpregset (&fpregs, regno);
 406
 407   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 408     perror_with_name (_("Couldn't write floating point status"));
 409 }
 410
 411 #else
 412
 413 static void fetch_fpregs (int tid) {}
 414 static void store_fpregs (int tid, int regno) {}
 415
 416 #endif
 417
 418 #endif
 419 \f
 420 /* Transferring arbitrary registers between GDB and inferior.  */
 421
 422 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 423    this for all registers (including the floating point and SSE
 424    registers).  */
 425
 426 static void
 427 m68k_linux_fetch_inferior_registers (int regno)
 428 {
 429   int tid;
 430
 431   /* Use the old method of peeking around in `struct user' if the
 432      GETREGS request isn't available.  */
 433   if (! have_ptrace_getregs)
 434     {
 435       old_fetch_inferior_registers (regno);
 436       return;
 437     }
 438
 439   /* GNU/Linux LWP ID's are process ID's.  */
 440   tid = TIDGET (inferior_ptid);
 441   if (tid == 0)
 442     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 443
 444   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 445      transfers more registers in one system call, and we'll cache the
 446      results.  But remember that fetch_fpxregs can fail, and return
 447      zero.  */
 448   if (regno == -1)
 449     {
 450       fetch_regs (tid);
 451
 452       /* The call above might reset `have_ptrace_getregs'.  */
 453       if (! have_ptrace_getregs)
 454         {
 455           old_fetch_inferior_registers (-1);
 456           return;
 457         }
 458
 459       fetch_fpregs (tid);
 460       return;
 461     }
 462
 463   if (getregs_supplies (regno))
 464     {
 465       fetch_regs (tid);
 466       return;
 467     }
 468
 469   if (getfpregs_supplies (regno))
 470     {
 471       fetch_fpregs (tid);
 472       return;
 473     }
 474
 475   internal_error (__FILE__, __LINE__,
 476                   _("Got request for bad register number %d."), regno);
 477 }
 478
 479 /* Store register REGNO back into the child process.  If REGNO is -1,
 480    do this for all registers (including the floating point and SSE
 481    registers).  */
 482 static void
 483 m68k_linux_store_inferior_registers (int regno)
 484 {
 485   int tid;
 486
 487   /* Use the old method of poking around in `struct user' if the
 488      SETREGS request isn't available.  */
 489   if (! have_ptrace_getregs)
 490     {
 491       old_store_inferior_registers (regno);
 492       return;
 493     }
 494
 495   /* GNU/Linux LWP ID's are process ID's.  */
 496   tid = TIDGET (inferior_ptid);
 497   if (tid == 0)
 498     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 499
 500   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 501      transfers more registers in one system call.  But remember that
 502      store_fpregs can fail, and return zero.  */
 503   if (regno == -1)
 504     {
 505       store_regs (tid, regno);
 506       store_fpregs (tid, regno);
 507       return;
 508     }
 509
 510   if (getregs_supplies (regno))
 511     {
 512       store_regs (tid, regno);
 513       return;
 514     }
 515
 516   if (getfpregs_supplies (regno))
 517     {
 518       store_fpregs (tid, regno);
 519       return;
 520     }
 521
 522   internal_error (__FILE__, __LINE__,
 523                   _("Got request to store bad register number %d."), regno);
 524 }
 525 \f
 526 /* Interpreting register set info found in core files.  */
 527
 528 /* Provide registers to GDB from a core file.
 529
 530    (We can't use the generic version of this function in
 531    core-regset.c, because we need to use elf_gregset_t instead of
 532    gregset_t.)
 533
 534    CORE_REG_SECT points to an array of bytes, which are the contents
 535    of a `note' from a core file which BFD thinks might contain
 536    register contents.  CORE_REG_SIZE is its size.
 537
 538    WHICH says which register set corelow suspects this is:
 539      0 --- the general-purpose register set, in elf_gregset_t format
 540      2 --- the floating-point register set, in elf_fpregset_t format
 541
 542    REG_ADDR isn't used on GNU/Linux.  */
 543
 544 static void
 545 fetch_core_registers (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 (&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 (&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 }