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 /* BLOCKEND is the value of u.u_ar0, and points to the place where GS
  96    is stored.  */
  97
  98 int
  99 m68k_linux_register_u_addr (int blockend, int regnum)
 100 {
 101   return (blockend + 4 * regmap[regnum]);
 102 }
 103 \f
 104
 105 /* Fetching registers directly from the U area, one at a time.  */
 106
 107 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 108    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 109    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 110    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 111    fall back on that code when GDB is running on top of a kernel that
 112    doesn't support the GETREGS request.  */
 113
 114 #ifndef PT_READ_U
 115 #define PT_READ_U PTRACE_PEEKUSR
 116 #endif
 117 #ifndef PT_WRITE_U
 118 #define PT_WRITE_U PTRACE_POKEUSR
 119 #endif
 120
 121 /* Fetch one register.  */
 122
 123 static void
 124 fetch_register (int regno)
 125 {
 126   /* This isn't really an address.  But ptrace thinks of it as one.  */
 127   CORE_ADDR regaddr;
 128   char mess[128];               /* For messages */
 129   int i;
 130   unsigned int offset;          /* Offset of registers within the u area.  */
 131   char buf[MAX_REGISTER_SIZE];
 132   int tid;
 133
 134   if (CANNOT_FETCH_REGISTER (regno))
 135     {
 136       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 137       regcache_raw_supply (current_regcache, regno, buf);
 138       return;
 139     }
 140
 141   /* Overload thread id onto process id */
 142   tid = TIDGET (inferior_ptid);
 143   if (tid == 0)
 144     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 145
 146   offset = U_REGS_OFFSET;
 147
 148   regaddr = register_addr (regno, offset);
 149   for (i = 0; i < register_size (current_gdbarch, regno);
 150        i += sizeof (PTRACE_TYPE_RET))
 151     {
 152       errno = 0;
 153       *(PTRACE_TYPE_RET *) &buf[i] = ptrace (PT_READ_U, tid,
 154                                               (PTRACE_TYPE_ARG3) regaddr, 0);
 155       regaddr += sizeof (PTRACE_TYPE_RET);
 156       if (errno != 0)
 157         {
 158           sprintf (mess, "reading register %s (#%d)",
 159                    REGISTER_NAME (regno), regno);
 160           perror_with_name (mess);
 161         }
 162     }
 163   regcache_raw_supply (current_regcache, regno, buf);
 164 }
 165
 166 /* Fetch register values from the inferior.
 167    If REGNO is negative, do this for all registers.
 168    Otherwise, REGNO specifies which register (so we can save time). */
 169
 170 static void
 171 old_fetch_inferior_registers (int regno)
 172 {
 173   if (regno >= 0)
 174     {
 175       fetch_register (regno);
 176     }
 177   else
 178     {
 179       for (regno = 0; regno < NUM_REGS; regno++)
 180         {
 181           fetch_register (regno);
 182         }
 183     }
 184 }
 185
 186 /* Store one register. */
 187
 188 static void
 189 store_register (int regno)
 190 {
 191   /* This isn't really an address.  But ptrace thinks of it as one.  */
 192   CORE_ADDR regaddr;
 193   char mess[128];               /* For messages */
 194   int i;
 195   unsigned int offset;          /* Offset of registers within the u area.  */
 196   int tid;
 197   char buf[MAX_REGISTER_SIZE];
 198
 199   if (CANNOT_STORE_REGISTER (regno))
 200     {
 201       return;
 202     }
 203
 204   /* Overload thread id onto process id */
 205   tid = TIDGET (inferior_ptid);
 206   if (tid == 0)
 207     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 208
 209   offset = U_REGS_OFFSET;
 210
 211   regaddr = register_addr (regno, offset);
 212
 213   /* Put the contents of regno into a local buffer */
 214   regcache_raw_collect (current_regcache, regno, buf);
 215
 216   /* Store the local buffer into the inferior a chunk at the time. */
 217   for (i = 0; i < register_size (current_gdbarch, regno);
 218        i += sizeof (PTRACE_TYPE_RET))
 219     {
 220       errno = 0;
 221       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 222               *(PTRACE_TYPE_RET *) (buf + i));
 223       regaddr += sizeof (PTRACE_TYPE_RET);
 224       if (errno != 0)
 225         {
 226           sprintf (mess, "writing register %s (#%d)",
 227                    REGISTER_NAME (regno), regno);
 228           perror_with_name (mess);
 229         }
 230     }
 231 }
 232
 233 /* Store our register values back into the inferior.
 234    If REGNO is negative, do this for all registers.
 235    Otherwise, REGNO specifies which register (so we can save time).  */
 236
 237 static void
 238 old_store_inferior_registers (int regno)
 239 {
 240   if (regno >= 0)
 241     {
 242       store_register (regno);
 243     }
 244   else
 245     {
 246       for (regno = 0; regno < NUM_REGS; regno++)
 247         {
 248           store_register (regno);
 249         }
 250     }
 251 }
 252 \f
 253 /*  Given a pointer to a general register set in /proc format
 254    (elf_gregset_t *), unpack the register contents and supply
 255    them as gdb's idea of the current register values. */
 256
 257
 258 /* Note both m68k-tdep.c and m68klinux-nat.c contain definitions
 259    for supply_gregset and supply_fpregset. The definitions
 260    in m68k-tdep.c are valid if USE_PROC_FS is defined. Otherwise,
 261    the definitions in m68klinux-nat.c will be used. This is a
 262    bit of a hack. The supply_* routines do not belong in
 263    *_tdep.c files. But, there are several lynx ports that currently
 264    depend on these definitions. */
 265
 266 #ifndef USE_PROC_FS
 267
 268 /* Prototypes for supply_gregset etc. */
 269 #include "gregset.h"
 270
 271 void
 272 supply_gregset (elf_gregset_t *gregsetp)
 273 {
 274   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 275   int regi;
 276
 277   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 278     regcache_raw_supply (current_regcache, regi, (char *) &regp[regmap[regi]]);
 279   regcache_raw_supply (current_regcache, PS_REGNUM, (char *) &regp[PT_SR]);
 280   regcache_raw_supply (current_regcache, PC_REGNUM, (char *) &regp[PT_PC]);
 281 }
 282
 283 /* Fill register REGNO (if it is a general-purpose register) in
 284    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 285    do this for all registers.  */
 286 void
 287 fill_gregset (elf_gregset_t *gregsetp, int regno)
 288 {
 289   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 290   int i;
 291
 292   for (i = 0; i < NUM_GREGS; i++)
 293     if (regno == -1 || regno == i)
 294       regcache_raw_collect (current_regcache, i, regp + regmap[i]);
 295 }
 296
 297 #ifdef HAVE_PTRACE_GETREGS
 298
 299 /* Fetch all general-purpose registers from process/thread TID and
 300    store their values in GDB's register array.  */
 301
 302 static void
 303 fetch_regs (int tid)
 304 {
 305   elf_gregset_t regs;
 306
 307   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 308     {
 309       if (errno == EIO)
 310         {
 311           /* The kernel we're running on doesn't support the GETREGS
 312              request.  Reset `have_ptrace_getregs'.  */
 313           have_ptrace_getregs = 0;
 314           return;
 315         }
 316
 317       perror_with_name (_("Couldn't get registers"));
 318     }
 319
 320   supply_gregset (&regs);
 321 }
 322
 323 /* Store all valid general-purpose registers in GDB's register array
 324    into the process/thread specified by TID.  */
 325
 326 static void
 327 store_regs (int tid, int regno)
 328 {
 329   elf_gregset_t regs;
 330
 331   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 332     perror_with_name (_("Couldn't get registers"));
 333
 334   fill_gregset (&regs, regno);
 335
 336   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 337     perror_with_name (_("Couldn't write registers"));
 338 }
 339
 340 #else
 341
 342 static void fetch_regs (int tid) {}
 343 static void store_regs (int tid, int regno) {}
 344
 345 #endif
 346
 347 \f
 348 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 349
 350 /* What is the address of fpN within the floating-point register set F?  */
 351 #define FPREG_ADDR(f, n) ((char *) &(f)->fpregs[(n) * 3])
 352
 353 /* Fill GDB's register array with the floating-point register values in
 354    *FPREGSETP.  */
 355
 356 void
 357 supply_fpregset (elf_fpregset_t *fpregsetp)
 358 {
 359   int regi;
 360
 361   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 362     regcache_raw_supply (current_regcache, regi,
 363                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 364   regcache_raw_supply (current_regcache, M68K_FPC_REGNUM,
 365                        (char *) &fpregsetp->fpcntl[0]);
 366   regcache_raw_supply (current_regcache, M68K_FPS_REGNUM,
 367                        (char *) &fpregsetp->fpcntl[1]);
 368   regcache_raw_supply (current_regcache, M68K_FPI_REGNUM,
 369                        (char *) &fpregsetp->fpcntl[2]);
 370 }
 371
 372 /* Fill register REGNO (if it is a floating-point register) in
 373    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 374    do this for all registers.  */
 375
 376 void
 377 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 378 {
 379   int i;
 380
 381   /* Fill in the floating-point registers.  */
 382   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 383     if (regno == -1 || regno == i)
 384       regcache_raw_collect (current_regcache, i,
 385                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 386
 387   /* Fill in the floating-point control registers.  */
 388   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 389     if (regno == -1 || regno == i)
 390       regcache_raw_collect (current_regcache, i,
 391                             (char *) &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 392 }
 393
 394 #ifdef HAVE_PTRACE_GETREGS
 395
 396 /* Fetch all floating-point registers from process/thread TID and store
 397    thier values in GDB's register array.  */
 398
 399 static void
 400 fetch_fpregs (int tid)
 401 {
 402   elf_fpregset_t fpregs;
 403
 404   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 405     perror_with_name (_("Couldn't get floating point status"));
 406
 407   supply_fpregset (&fpregs);
 408 }
 409
 410 /* Store all valid floating-point registers in GDB's register array
 411    into the process/thread specified by TID.  */
 412
 413 static void
 414 store_fpregs (int tid, int regno)
 415 {
 416   elf_fpregset_t fpregs;
 417
 418   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 419     perror_with_name (_("Couldn't get floating point status"));
 420
 421   fill_fpregset (&fpregs, regno);
 422
 423   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 424     perror_with_name (_("Couldn't write floating point status"));
 425 }
 426
 427 #else
 428
 429 static void fetch_fpregs (int tid) {}
 430 static void store_fpregs (int tid, int regno) {}
 431
 432 #endif
 433
 434 #endif
 435 \f
 436 /* Transferring arbitrary registers between GDB and inferior.  */
 437
 438 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 439    this for all registers (including the floating point and SSE
 440    registers).  */
 441
 442 static void
 443 m68k_linux_fetch_inferior_registers (int regno)
 444 {
 445   int tid;
 446
 447   /* Use the old method of peeking around in `struct user' if the
 448      GETREGS request isn't available.  */
 449   if (! have_ptrace_getregs)
 450     {
 451       old_fetch_inferior_registers (regno);
 452       return;
 453     }
 454
 455   /* GNU/Linux LWP ID's are process ID's.  */
 456   tid = TIDGET (inferior_ptid);
 457   if (tid == 0)
 458     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 459
 460   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 461      transfers more registers in one system call, and we'll cache the
 462      results.  But remember that fetch_fpxregs can fail, and return
 463      zero.  */
 464   if (regno == -1)
 465     {
 466       fetch_regs (tid);
 467
 468       /* The call above might reset `have_ptrace_getregs'.  */
 469       if (! have_ptrace_getregs)
 470         {
 471           old_fetch_inferior_registers (-1);
 472           return;
 473         }
 474
 475       fetch_fpregs (tid);
 476       return;
 477     }
 478
 479   if (getregs_supplies (regno))
 480     {
 481       fetch_regs (tid);
 482       return;
 483     }
 484
 485   if (getfpregs_supplies (regno))
 486     {
 487       fetch_fpregs (tid);
 488       return;
 489     }
 490
 491   internal_error (__FILE__, __LINE__,
 492                   _("Got request for bad register number %d."), regno);
 493 }
 494
 495 /* Store register REGNO back into the child process.  If REGNO is -1,
 496    do this for all registers (including the floating point and SSE
 497    registers).  */
 498 static void
 499 m68k_linux_store_inferior_registers (int regno)
 500 {
 501   int tid;
 502
 503   /* Use the old method of poking around in `struct user' if the
 504      SETREGS request isn't available.  */
 505   if (! have_ptrace_getregs)
 506     {
 507       old_store_inferior_registers (regno);
 508       return;
 509     }
 510
 511   /* GNU/Linux LWP ID's are process ID's.  */
 512   tid = TIDGET (inferior_ptid);
 513   if (tid == 0)
 514     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 515
 516   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 517      transfers more registers in one system call.  But remember that
 518      store_fpregs can fail, and return zero.  */
 519   if (regno == -1)
 520     {
 521       store_regs (tid, regno);
 522       store_fpregs (tid, regno);
 523       return;
 524     }
 525
 526   if (getregs_supplies (regno))
 527     {
 528       store_regs (tid, regno);
 529       return;
 530     }
 531
 532   if (getfpregs_supplies (regno))
 533     {
 534       store_fpregs (tid, regno);
 535       return;
 536     }
 537
 538   internal_error (__FILE__, __LINE__,
 539                   _("Got request to store bad register number %d."), regno);
 540 }
 541 \f
 542 /* Interpreting register set info found in core files.  */
 543
 544 /* Provide registers to GDB from a core file.
 545
 546    (We can't use the generic version of this function in
 547    core-regset.c, because we need to use elf_gregset_t instead of
 548    gregset_t.)
 549
 550    CORE_REG_SECT points to an array of bytes, which are the contents
 551    of a `note' from a core file which BFD thinks might contain
 552    register contents.  CORE_REG_SIZE is its size.
 553
 554    WHICH says which register set corelow suspects this is:
 555      0 --- the general-purpose register set, in elf_gregset_t format
 556      2 --- the floating-point register set, in elf_fpregset_t format
 557
 558    REG_ADDR isn't used on GNU/Linux.  */
 559
 560 static void
 561 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size,
 562                       int which, CORE_ADDR reg_addr)
 563 {
 564   elf_gregset_t gregset;
 565   elf_fpregset_t fpregset;
 566
 567   switch (which)
 568     {
 569     case 0:
 570       if (core_reg_size != sizeof (gregset))
 571         warning (_("Wrong size gregset in core file."));
 572       else
 573         {
 574           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 575           supply_gregset (&gregset);
 576         }
 577       break;
 578
 579     case 2:
 580       if (core_reg_size != sizeof (fpregset))
 581         warning (_("Wrong size fpregset in core file."));
 582       else
 583         {
 584           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 585           supply_fpregset (&fpregset);
 586         }
 587       break;
 588
 589     default:
 590       /* We've covered all the kinds of registers we know about here,
 591          so this must be something we wouldn't know what to do with
 592          anyway.  Just ignore it.  */
 593       break;
 594     }
 595 }
 596 \f
 597
 598 int
 599 kernel_u_size (void)
 600 {
 601   return (sizeof (struct user));
 602 }
 603 \f
 604 /* Register that we are able to handle GNU/Linux ELF core file
 605    formats.  */
 606
 607 static struct core_fns linux_elf_core_fns =
 608 {
 609   bfd_target_elf_flavour,               /* core_flavour */
 610   default_check_format,                 /* check_format */
 611   default_core_sniffer,                 /* core_sniffer */
 612   fetch_core_registers,                 /* core_read_registers */
 613   NULL                                  /* next */
 614 };
 615
 616 void _initialize_m68k_linux_nat (void);
 617
 618 void
 619 _initialize_m68k_linux_nat (void)
 620 {
 621   struct target_ops *t;
 622
 623   /* Fill in the generic GNU/Linux methods.  */
 624   t = linux_target ();
 625
 626   /* Add our register access methods.  */
 627   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 628   t->to_store_registers = m68k_linux_store_inferior_registers;
 629
 630   /* Register the target.  */
 631   linux_nat_add_target (t);
 632
 633   deprecated_add_core_fns (&linux_elf_core_fns);
 634 }