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    2008, 2009, 2010, 2011 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 M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  83 }
  84
  85 /* Does the current host support the GETREGS request?  */
  86 int have_ptrace_getregs =
  87 #ifdef HAVE_PTRACE_GETREGS
  88   1
  89 #else
  90   0
  91 #endif
  92 ;
  93
  94 \f
  95
  96 /* Fetching registers directly from the U area, one at a time.  */
  97
  98 /* Fetch one register.  */
  99
 100 static void
 101 fetch_register (struct regcache *regcache, int regno)
 102 {
 103   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 104   long regaddr;
 105   int i;
 106   char buf[MAX_REGISTER_SIZE];
 107   int tid;
 108
 109   /* Overload thread id onto process id.  */
 110   tid = TIDGET (inferior_ptid);
 111   if (tid == 0)
 112     tid = PIDGET (inferior_ptid);       /* no thread id, just use
 113                                            process id.  */
 114
 115   regaddr = 4 * regmap[regno];
 116   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 117     {
 118       errno = 0;
 119       *(long *) &buf[i] = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 120       regaddr += sizeof (long);
 121       if (errno != 0)
 122         error (_("Couldn't read register %s (#%d): %s."),
 123                gdbarch_register_name (gdbarch, regno),
 124                regno, safe_strerror (errno));
 125     }
 126   regcache_raw_supply (regcache, regno, buf);
 127 }
 128
 129 /* Fetch register values from the inferior.
 130    If REGNO is negative, do this for all registers.
 131    Otherwise, REGNO specifies which register (so we can save time).  */
 132
 133 static void
 134 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 135 {
 136   if (regno >= 0)
 137     {
 138       fetch_register (regcache, regno);
 139     }
 140   else
 141     {
 142       for (regno = 0;
 143            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 144            regno++)
 145         {
 146           fetch_register (regcache, regno);
 147         }
 148     }
 149 }
 150
 151 /* Store one register.  */
 152
 153 static void
 154 store_register (const struct regcache *regcache, int regno)
 155 {
 156   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 157   long regaddr;
 158   int i;
 159   int tid;
 160   char buf[MAX_REGISTER_SIZE];
 161
 162   /* Overload thread id onto process id.  */
 163   tid = TIDGET (inferior_ptid);
 164   if (tid == 0)
 165     tid = PIDGET (inferior_ptid);       /* no thread id, just use
 166                                            process id.  */
 167
 168   regaddr = 4 * regmap[regno];
 169
 170   /* Put the contents of regno into a local buffer.  */
 171   regcache_raw_collect (regcache, regno, buf);
 172
 173   /* Store the local buffer into the inferior a chunk at the time.  */
 174   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 175     {
 176       errno = 0;
 177       ptrace (PTRACE_POKEUSER, tid, regaddr, *(long *) &buf[i]);
 178       regaddr += sizeof (long);
 179       if (errno != 0)
 180         error (_("Couldn't write register %s (#%d): %s."),
 181                gdbarch_register_name (gdbarch, regno),
 182                regno, safe_strerror (errno));
 183     }
 184 }
 185
 186 /* Store our register values back into the inferior.
 187    If REGNO is negative, do this for all registers.
 188    Otherwise, REGNO specifies which register (so we can save time).  */
 189
 190 static void
 191 old_store_inferior_registers (const struct regcache *regcache, int regno)
 192 {
 193   if (regno >= 0)
 194     {
 195       store_register (regcache, regno);
 196     }
 197   else
 198     {
 199       for (regno = 0;
 200            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 201            regno++)
 202         {
 203           store_register (regcache, regno);
 204         }
 205     }
 206 }
 207 \f
 208 /*  Given a pointer to a general register set in /proc format
 209    (elf_gregset_t *), unpack the register contents and supply
 210    them as gdb's idea of the current register values.  */
 211
 212 void
 213 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 214 {
 215   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 216   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 217   int regi;
 218
 219   for (regi = M68K_D0_REGNUM;
 220        regi <= gdbarch_sp_regnum (gdbarch);
 221        regi++)
 222     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 223   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 224                        &regp[PT_SR]);
 225   regcache_raw_supply (regcache,
 226                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 227 }
 228
 229 /* Fill register REGNO (if it is a general-purpose register) in
 230    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 231    do this for all registers.  */
 232 void
 233 fill_gregset (const struct regcache *regcache,
 234               elf_gregset_t *gregsetp, int regno)
 235 {
 236   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 237   int i;
 238
 239   for (i = 0; i < NUM_GREGS; i++)
 240     if (regno == -1 || regno == i)
 241       regcache_raw_collect (regcache, i, regp + regmap[i]);
 242 }
 243
 244 #ifdef HAVE_PTRACE_GETREGS
 245
 246 /* Fetch all general-purpose registers from process/thread TID and
 247    store their values in GDB's register array.  */
 248
 249 static void
 250 fetch_regs (struct regcache *regcache, int tid)
 251 {
 252   elf_gregset_t regs;
 253
 254   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 255     {
 256       if (errno == EIO)
 257         {
 258           /* The kernel we're running on doesn't support the GETREGS
 259              request.  Reset `have_ptrace_getregs'.  */
 260           have_ptrace_getregs = 0;
 261           return;
 262         }
 263
 264       perror_with_name (_("Couldn't get registers"));
 265     }
 266
 267   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 268 }
 269
 270 /* Store all valid general-purpose registers in GDB's register array
 271    into the process/thread specified by TID.  */
 272
 273 static void
 274 store_regs (const struct regcache *regcache, int tid, int regno)
 275 {
 276   elf_gregset_t regs;
 277
 278   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 279     perror_with_name (_("Couldn't get registers"));
 280
 281   fill_gregset (regcache, &regs, regno);
 282
 283   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 284     perror_with_name (_("Couldn't write registers"));
 285 }
 286
 287 #else
 288
 289 static void fetch_regs (struct regcache *regcache, int tid)
 290 {
 291 }
 292
 293 static void store_regs (const struct regcache *regcache, int tid, int regno)
 294 {
 295 }
 296
 297 #endif
 298
 299 \f
 300 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 301
 302 /* What is the address of fpN within the floating-point register set F?  */
 303 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 304
 305 /* Fill GDB's register array with the floating-point register values in
 306    *FPREGSETP.  */
 307
 308 void
 309 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 310 {
 311   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 312   int regi;
 313
 314   for (regi = gdbarch_fp0_regnum (gdbarch);
 315        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 316     regcache_raw_supply (regcache, regi,
 317                          FPREG_ADDR (fpregsetp,
 318                                      regi - gdbarch_fp0_regnum (gdbarch)));
 319   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 320   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 321   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 322 }
 323
 324 /* Fill register REGNO (if it is a floating-point register) in
 325    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 326    do this for all registers.  */
 327
 328 void
 329 fill_fpregset (const struct regcache *regcache,
 330                elf_fpregset_t *fpregsetp, int regno)
 331 {
 332   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 333   int i;
 334
 335   /* Fill in the floating-point registers.  */
 336   for (i = gdbarch_fp0_regnum (gdbarch);
 337        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 338     if (regno == -1 || regno == i)
 339       regcache_raw_collect (regcache, i,
 340                             FPREG_ADDR (fpregsetp,
 341                                         i - gdbarch_fp0_regnum (gdbarch)));
 342
 343   /* Fill in the floating-point control registers.  */
 344   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 345     if (regno == -1 || regno == i)
 346       regcache_raw_collect (regcache, i,
 347                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 348 }
 349
 350 #ifdef HAVE_PTRACE_GETREGS
 351
 352 /* Fetch all floating-point registers from process/thread TID and store
 353    thier values in GDB's register array.  */
 354
 355 static void
 356 fetch_fpregs (struct regcache *regcache, int tid)
 357 {
 358   elf_fpregset_t fpregs;
 359
 360   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 361     perror_with_name (_("Couldn't get floating point status"));
 362
 363   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 364 }
 365
 366 /* Store all valid floating-point registers in GDB's register array
 367    into the process/thread specified by TID.  */
 368
 369 static void
 370 store_fpregs (const struct regcache *regcache, int tid, int regno)
 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   fill_fpregset (regcache, &fpregs, regno);
 378
 379   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 380     perror_with_name (_("Couldn't write floating point status"));
 381 }
 382
 383 #else
 384
 385 static void fetch_fpregs (struct regcache *regcache, int tid)
 386 {
 387 }
 388
 389 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 390 {
 391 }
 392
 393 #endif
 394 \f
 395 /* Transferring arbitrary registers between GDB and inferior.  */
 396
 397 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 398    this for all registers (including the floating point and SSE
 399    registers).  */
 400
 401 static void
 402 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 403                                      struct regcache *regcache, int regno)
 404 {
 405   int tid;
 406
 407   /* Use the old method of peeking around in `struct user' if the
 408      GETREGS request isn't available.  */
 409   if (! have_ptrace_getregs)
 410     {
 411       old_fetch_inferior_registers (regcache, regno);
 412       return;
 413     }
 414
 415   /* GNU/Linux LWP ID's are process ID's.  */
 416   tid = TIDGET (inferior_ptid);
 417   if (tid == 0)
 418     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 419
 420   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 421      transfers more registers in one system call, and we'll cache the
 422      results.  But remember that fetch_fpxregs can fail, and return
 423      zero.  */
 424   if (regno == -1)
 425     {
 426       fetch_regs (regcache, tid);
 427
 428       /* The call above might reset `have_ptrace_getregs'.  */
 429       if (! have_ptrace_getregs)
 430         {
 431           old_fetch_inferior_registers (regcache, -1);
 432           return;
 433         }
 434
 435       fetch_fpregs (regcache, tid);
 436       return;
 437     }
 438
 439   if (getregs_supplies (regno))
 440     {
 441       fetch_regs (regcache, tid);
 442       return;
 443     }
 444
 445   if (getfpregs_supplies (regno))
 446     {
 447       fetch_fpregs (regcache, tid);
 448       return;
 449     }
 450
 451   internal_error (__FILE__, __LINE__,
 452                   _("Got request for bad register number %d."), regno);
 453 }
 454
 455 /* Store register REGNO back into the child process.  If REGNO is -1,
 456    do this for all registers (including the floating point and SSE
 457    registers).  */
 458 static void
 459 m68k_linux_store_inferior_registers (struct target_ops *ops,
 460                                      struct regcache *regcache, int regno)
 461 {
 462   int tid;
 463
 464   /* Use the old method of poking around in `struct user' if the
 465      SETREGS request isn't available.  */
 466   if (! have_ptrace_getregs)
 467     {
 468       old_store_inferior_registers (regcache, regno);
 469       return;
 470     }
 471
 472   /* GNU/Linux LWP ID's are process ID's.  */
 473   tid = TIDGET (inferior_ptid);
 474   if (tid == 0)
 475     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 476
 477   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 478      transfers more registers in one system call.  But remember that
 479      store_fpregs can fail, and return zero.  */
 480   if (regno == -1)
 481     {
 482       store_regs (regcache, tid, regno);
 483       store_fpregs (regcache, tid, regno);
 484       return;
 485     }
 486
 487   if (getregs_supplies (regno))
 488     {
 489       store_regs (regcache, tid, regno);
 490       return;
 491     }
 492
 493   if (getfpregs_supplies (regno))
 494     {
 495       store_fpregs (regcache, tid, regno);
 496       return;
 497     }
 498
 499   internal_error (__FILE__, __LINE__,
 500                   _("Got request to store bad register number %d."), regno);
 501 }
 502 \f
 503 /* Interpreting register set info found in core files.  */
 504
 505 /* Provide registers to GDB from a core file.
 506
 507    (We can't use the generic version of this function in
 508    core-regset.c, because we need to use elf_gregset_t instead of
 509    gregset_t.)
 510
 511    CORE_REG_SECT points to an array of bytes, which are the contents
 512    of a `note' from a core file which BFD thinks might contain
 513    register contents.  CORE_REG_SIZE is its size.
 514
 515    WHICH says which register set corelow suspects this is:
 516      0 --- the general-purpose register set, in elf_gregset_t format
 517      2 --- the floating-point register set, in elf_fpregset_t format
 518
 519    REG_ADDR isn't used on GNU/Linux.  */
 520
 521 static void
 522 fetch_core_registers (struct regcache *regcache,
 523                       char *core_reg_sect, unsigned core_reg_size,
 524                       int which, CORE_ADDR reg_addr)
 525 {
 526   elf_gregset_t gregset;
 527   elf_fpregset_t fpregset;
 528
 529   switch (which)
 530     {
 531     case 0:
 532       if (core_reg_size != sizeof (gregset))
 533         warning (_("Wrong size gregset in core file."));
 534       else
 535         {
 536           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 537           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 538         }
 539       break;
 540
 541     case 2:
 542       if (core_reg_size != sizeof (fpregset))
 543         warning (_("Wrong size fpregset in core file."));
 544       else
 545         {
 546           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 547           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 548         }
 549       break;
 550
 551     default:
 552       /* We've covered all the kinds of registers we know about here,
 553          so this must be something we wouldn't know what to do with
 554          anyway.  Just ignore it.  */
 555       break;
 556     }
 557 }
 558 \f
 559
 560 /* Register that we are able to handle GNU/Linux ELF core file
 561    formats.  */
 562
 563 static struct core_fns linux_elf_core_fns =
 564 {
 565   bfd_target_elf_flavour,               /* core_flavour */
 566   default_check_format,                 /* check_format */
 567   default_core_sniffer,                 /* core_sniffer */
 568   fetch_core_registers,                 /* core_read_registers */
 569   NULL                                  /* next */
 570 };
 571
 572 void _initialize_m68k_linux_nat (void);
 573
 574 void
 575 _initialize_m68k_linux_nat (void)
 576 {
 577   struct target_ops *t;
 578
 579   /* Fill in the generic GNU/Linux methods.  */
 580   t = linux_target ();
 581
 582   /* Add our register access methods.  */
 583   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 584   t->to_store_registers = m68k_linux_store_inferior_registers;
 585
 586   /* Register the target.  */
 587   linux_nat_add_target (t);
 588
 589   deprecated_add_core_fns (&linux_elf_core_fns);
 590 }