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 FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  85 }
  86
  87 /* Does the current host support the GETREGS request?  */
  88 int have_ptrace_getregs =
  89 #ifdef HAVE_PTRACE_GETREGS
  90   1
  91 #else
  92   0
  93 #endif
  94 ;
  95
  96 \f
  97
  98 /* Fetching registers directly from the U area, one at a time.  */
  99
 100 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 101    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 102    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 103    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 104    fall back on that code when GDB is running on top of a kernel that
 105    doesn't support the GETREGS request.  */
 106
 107 #ifndef PT_READ_U
 108 #define PT_READ_U PTRACE_PEEKUSR
 109 #endif
 110 #ifndef PT_WRITE_U
 111 #define PT_WRITE_U PTRACE_POKEUSR
 112 #endif
 113
 114 /* Fetch one register.  */
 115
 116 static void
 117 fetch_register (struct regcache *regcache, int regno)
 118 {
 119   /* This isn't really an address.  But ptrace thinks of it as one.  */
 120   CORE_ADDR regaddr;
 121   char mess[128];               /* For messages */
 122   int i;
 123   char buf[MAX_REGISTER_SIZE];
 124   int tid;
 125
 126   if (gdbarch_cannot_fetch_register (current_gdbarch, regno))
 127     {
 128       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 129       regcache_raw_supply (regcache, regno, buf);
 130       return;
 131     }
 132
 133   /* Overload thread id onto process id */
 134   tid = TIDGET (inferior_ptid);
 135   if (tid == 0)
 136     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 137
 138   regaddr = 4 * regmap[regno];
 139   for (i = 0; i < register_size (current_gdbarch, regno);
 140        i += sizeof (PTRACE_TYPE_RET))
 141     {
 142       errno = 0;
 143       *(PTRACE_TYPE_RET *) &buf[i] = ptrace (PT_READ_U, tid,
 144                                               (PTRACE_TYPE_ARG3) regaddr, 0);
 145       regaddr += sizeof (PTRACE_TYPE_RET);
 146       if (errno != 0)
 147         {
 148           sprintf (mess, "reading register %s (#%d)",
 149                    gdbarch_register_name (current_gdbarch, regno), regno);
 150           perror_with_name (mess);
 151         }
 152     }
 153   regcache_raw_supply (regcache, regno, buf);
 154 }
 155
 156 /* Fetch register values from the inferior.
 157    If REGNO is negative, do this for all registers.
 158    Otherwise, REGNO specifies which register (so we can save time). */
 159
 160 static void
 161 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 162 {
 163   if (regno >= 0)
 164     {
 165       fetch_register (regcache, regno);
 166     }
 167   else
 168     {
 169       for (regno = 0; regno < gdbarch_num_regs (current_gdbarch); regno++)
 170         {
 171           fetch_register (regcache, regno);
 172         }
 173     }
 174 }
 175
 176 /* Store one register. */
 177
 178 static void
 179 store_register (const struct regcache *regcache, int regno)
 180 {
 181   /* This isn't really an address.  But ptrace thinks of it as one.  */
 182   CORE_ADDR regaddr;
 183   char mess[128];               /* For messages */
 184   int i;
 185   int tid;
 186   char buf[MAX_REGISTER_SIZE];
 187
 188   if (gdbarch_cannot_store_register (current_gdbarch, regno))
 189     return;
 190
 191   /* Overload thread id onto process id */
 192   tid = TIDGET (inferior_ptid);
 193   if (tid == 0)
 194     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 195
 196   regaddr = 4 * regmap[regno];
 197
 198   /* Put the contents of regno into a local buffer */
 199   regcache_raw_collect (regcache, regno, buf);
 200
 201   /* Store the local buffer into the inferior a chunk at the time. */
 202   for (i = 0; i < register_size (current_gdbarch, regno);
 203        i += sizeof (PTRACE_TYPE_RET))
 204     {
 205       errno = 0;
 206       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 207               *(PTRACE_TYPE_RET *) (buf + i));
 208       regaddr += sizeof (PTRACE_TYPE_RET);
 209       if (errno != 0)
 210         {
 211           sprintf (mess, "writing register %s (#%d)",
 212                    gdbarch_register_name (current_gdbarch, regno), regno);
 213           perror_with_name (mess);
 214         }
 215     }
 216 }
 217
 218 /* Store our register values back into the inferior.
 219    If REGNO is negative, do this for all registers.
 220    Otherwise, REGNO specifies which register (so we can save time).  */
 221
 222 static void
 223 old_store_inferior_registers (const struct regcache *regcache, int regno)
 224 {
 225   if (regno >= 0)
 226     {
 227       store_register (regcache, regno);
 228     }
 229   else
 230     {
 231       for (regno = 0; regno < gdbarch_num_regs (current_gdbarch); regno++)
 232         {
 233           store_register (regcache, regno);
 234         }
 235     }
 236 }
 237 \f
 238 /*  Given a pointer to a general register set in /proc format
 239    (elf_gregset_t *), unpack the register contents and supply
 240    them as gdb's idea of the current register values. */
 241
 242 void
 243 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 244 {
 245   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 246   int regi;
 247
 248   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 249     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 250   regcache_raw_supply (regcache, PS_REGNUM, &regp[PT_SR]);
 251   regcache_raw_supply (regcache, PC_REGNUM, &regp[PT_PC]);
 252 }
 253
 254 /* Fill register REGNO (if it is a general-purpose register) in
 255    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 256    do this for all registers.  */
 257 void
 258 fill_gregset (const struct regcache *regcache,
 259               elf_gregset_t *gregsetp, int regno)
 260 {
 261   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 262   int i;
 263
 264   for (i = 0; i < NUM_GREGS; i++)
 265     if (regno == -1 || regno == i)
 266       regcache_raw_collect (regcache, i, regp + regmap[i]);
 267 }
 268
 269 #ifdef HAVE_PTRACE_GETREGS
 270
 271 /* Fetch all general-purpose registers from process/thread TID and
 272    store their values in GDB's register array.  */
 273
 274 static void
 275 fetch_regs (struct regcache *regcache, int tid)
 276 {
 277   elf_gregset_t regs;
 278
 279   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 280     {
 281       if (errno == EIO)
 282         {
 283           /* The kernel we're running on doesn't support the GETREGS
 284              request.  Reset `have_ptrace_getregs'.  */
 285           have_ptrace_getregs = 0;
 286           return;
 287         }
 288
 289       perror_with_name (_("Couldn't get registers"));
 290     }
 291
 292   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 293 }
 294
 295 /* Store all valid general-purpose registers in GDB's register array
 296    into the process/thread specified by TID.  */
 297
 298 static void
 299 store_regs (const struct regcache *regcache, int tid, int regno)
 300 {
 301   elf_gregset_t regs;
 302
 303   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 304     perror_with_name (_("Couldn't get registers"));
 305
 306   fill_gregset (regcache, &regs, regno);
 307
 308   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 309     perror_with_name (_("Couldn't write registers"));
 310 }
 311
 312 #else
 313
 314 static void fetch_regs (struct regcache *regcache, int tid) {}
 315 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 316
 317 #endif
 318
 319 \f
 320 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 321
 322 /* What is the address of fpN within the floating-point register set F?  */
 323 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 324
 325 /* Fill GDB's register array with the floating-point register values in
 326    *FPREGSETP.  */
 327
 328 void
 329 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 330 {
 331   int regi;
 332
 333   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 334     regcache_raw_supply (regcache, regi,
 335                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 336   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 337   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 338   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 339 }
 340
 341 /* Fill register REGNO (if it is a floating-point register) in
 342    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 343    do this for all registers.  */
 344
 345 void
 346 fill_fpregset (const struct regcache *regcache,
 347                elf_fpregset_t *fpregsetp, int regno)
 348 {
 349   int i;
 350
 351   /* Fill in the floating-point registers.  */
 352   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 353     if (regno == -1 || regno == i)
 354       regcache_raw_collect (regcache, i,
 355                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 356
 357   /* Fill in the floating-point control registers.  */
 358   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 359     if (regno == -1 || regno == i)
 360       regcache_raw_collect (regcache, i,
 361                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 362 }
 363
 364 #ifdef HAVE_PTRACE_GETREGS
 365
 366 /* Fetch all floating-point registers from process/thread TID and store
 367    thier values in GDB's register array.  */
 368
 369 static void
 370 fetch_fpregs (struct regcache *regcache, int tid)
 371 {
 372   elf_fpregset_t fpregs;
 373
 374   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 375     perror_with_name (_("Couldn't get floating point status"));
 376
 377   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 378 }
 379
 380 /* Store all valid floating-point registers in GDB's register array
 381    into the process/thread specified by TID.  */
 382
 383 static void
 384 store_fpregs (const struct regcache *regcache, int tid, int regno)
 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   fill_fpregset (regcache, &fpregs, regno);
 392
 393   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 394     perror_with_name (_("Couldn't write floating point status"));
 395 }
 396
 397 #else
 398
 399 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 400 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 401
 402 #endif
 403 \f
 404 /* Transferring arbitrary registers between GDB and inferior.  */
 405
 406 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 407    this for all registers (including the floating point and SSE
 408    registers).  */
 409
 410 static void
 411 m68k_linux_fetch_inferior_registers (struct regcache *regcache, int regno)
 412 {
 413   int tid;
 414
 415   /* Use the old method of peeking around in `struct user' if the
 416      GETREGS request isn't available.  */
 417   if (! have_ptrace_getregs)
 418     {
 419       old_fetch_inferior_registers (regcache, regno);
 420       return;
 421     }
 422
 423   /* GNU/Linux LWP ID's are process ID's.  */
 424   tid = TIDGET (inferior_ptid);
 425   if (tid == 0)
 426     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 427
 428   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 429      transfers more registers in one system call, and we'll cache the
 430      results.  But remember that fetch_fpxregs can fail, and return
 431      zero.  */
 432   if (regno == -1)
 433     {
 434       fetch_regs (regcache, tid);
 435
 436       /* The call above might reset `have_ptrace_getregs'.  */
 437       if (! have_ptrace_getregs)
 438         {
 439           old_fetch_inferior_registers (regcache, -1);
 440           return;
 441         }
 442
 443       fetch_fpregs (regcache, tid);
 444       return;
 445     }
 446
 447   if (getregs_supplies (regno))
 448     {
 449       fetch_regs (regcache, tid);
 450       return;
 451     }
 452
 453   if (getfpregs_supplies (regno))
 454     {
 455       fetch_fpregs (regcache, tid);
 456       return;
 457     }
 458
 459   internal_error (__FILE__, __LINE__,
 460                   _("Got request for bad register number %d."), regno);
 461 }
 462
 463 /* Store register REGNO back into the child process.  If REGNO is -1,
 464    do this for all registers (including the floating point and SSE
 465    registers).  */
 466 static void
 467 m68k_linux_store_inferior_registers (struct regcache *regcache, int regno)
 468 {
 469   int tid;
 470
 471   /* Use the old method of poking around in `struct user' if the
 472      SETREGS request isn't available.  */
 473   if (! have_ptrace_getregs)
 474     {
 475       old_store_inferior_registers (regcache, regno);
 476       return;
 477     }
 478
 479   /* GNU/Linux LWP ID's are process ID's.  */
 480   tid = TIDGET (inferior_ptid);
 481   if (tid == 0)
 482     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 483
 484   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 485      transfers more registers in one system call.  But remember that
 486      store_fpregs can fail, and return zero.  */
 487   if (regno == -1)
 488     {
 489       store_regs (regcache, tid, regno);
 490       store_fpregs (regcache, tid, regno);
 491       return;
 492     }
 493
 494   if (getregs_supplies (regno))
 495     {
 496       store_regs (regcache, tid, regno);
 497       return;
 498     }
 499
 500   if (getfpregs_supplies (regno))
 501     {
 502       store_fpregs (regcache, tid, regno);
 503       return;
 504     }
 505
 506   internal_error (__FILE__, __LINE__,
 507                   _("Got request to store bad register number %d."), regno);
 508 }
 509 \f
 510 /* Interpreting register set info found in core files.  */
 511
 512 /* Provide registers to GDB from a core file.
 513
 514    (We can't use the generic version of this function in
 515    core-regset.c, because we need to use elf_gregset_t instead of
 516    gregset_t.)
 517
 518    CORE_REG_SECT points to an array of bytes, which are the contents
 519    of a `note' from a core file which BFD thinks might contain
 520    register contents.  CORE_REG_SIZE is its size.
 521
 522    WHICH says which register set corelow suspects this is:
 523      0 --- the general-purpose register set, in elf_gregset_t format
 524      2 --- the floating-point register set, in elf_fpregset_t format
 525
 526    REG_ADDR isn't used on GNU/Linux.  */
 527
 528 static void
 529 fetch_core_registers (struct regcache *regcache,
 530                       char *core_reg_sect, unsigned core_reg_size,
 531                       int which, CORE_ADDR reg_addr)
 532 {
 533   elf_gregset_t gregset;
 534   elf_fpregset_t fpregset;
 535
 536   switch (which)
 537     {
 538     case 0:
 539       if (core_reg_size != sizeof (gregset))
 540         warning (_("Wrong size gregset in core file."));
 541       else
 542         {
 543           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 544           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 545         }
 546       break;
 547
 548     case 2:
 549       if (core_reg_size != sizeof (fpregset))
 550         warning (_("Wrong size fpregset in core file."));
 551       else
 552         {
 553           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 554           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 555         }
 556       break;
 557
 558     default:
 559       /* We've covered all the kinds of registers we know about here,
 560          so this must be something we wouldn't know what to do with
 561          anyway.  Just ignore it.  */
 562       break;
 563     }
 564 }
 565 \f
 566
 567 /* Register that we are able to handle GNU/Linux ELF core file
 568    formats.  */
 569
 570 static struct core_fns linux_elf_core_fns =
 571 {
 572   bfd_target_elf_flavour,               /* core_flavour */
 573   default_check_format,                 /* check_format */
 574   default_core_sniffer,                 /* core_sniffer */
 575   fetch_core_registers,                 /* core_read_registers */
 576   NULL                                  /* next */
 577 };
 578
 579 void _initialize_m68k_linux_nat (void);
 580
 581 void
 582 _initialize_m68k_linux_nat (void)
 583 {
 584   struct target_ops *t;
 585
 586   /* Fill in the generic GNU/Linux methods.  */
 587   t = linux_target ();
 588
 589   /* Add our register access methods.  */
 590   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 591   t->to_store_registers = m68k_linux_store_inferior_registers;
 592
 593   /* Register the target.  */
 594   linux_nat_add_target (t);
 595
 596   deprecated_add_core_fns (&linux_elf_core_fns);
 597 }