gdb/m68klinux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright (C) 1996-2013 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "frame.h"
  22 #include "inferior.h"
  23 #include "language.h"
  24 #include "gdbcore.h"
  25 #include "gdb_string.h"
  26 #include "regcache.h"
  27 #include "target.h"
  28 #include "linux-nat.h"
  29
  30 #include "m68k-tdep.h"
  31
  32 #include <sys/param.h>
  33 #include <sys/dir.h>
  34 #include <signal.h>
  35 #include <sys/ptrace.h>
  36 #include <sys/user.h>
  37 #include <sys/ioctl.h>
  38 #include <fcntl.h>
  39 #include <sys/procfs.h>
  40
  41 #ifdef HAVE_SYS_REG_H
  42 #include <sys/reg.h>
  43 #endif
  44
  45 #include <sys/file.h>
  46 #include "gdb_stat.h"
  47
  48 #include "floatformat.h"
  49
  50 #include "target.h"
  51
  52 /* Prototypes for supply_gregset etc.  */
  53 #include "gregset.h"
  54
  55 /* Defines ps_err_e, struct ps_prochandle.  */
  56 #include "gdb_proc_service.h"
  57
  58 #ifndef PTRACE_GET_THREAD_AREA
  59 #define PTRACE_GET_THREAD_AREA 25
  60 #endif
  61 \f
  62 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  63 static const int regmap[] =
  64 {
  65   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  66   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  67   PT_SR, PT_PC,
  68   /* PT_FP0, ..., PT_FP7 */
  69   21, 24, 27, 30, 33, 36, 39, 42,
  70   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  71   45, 46, 47
  72 };
  73
  74 /* Which ptrace request retrieves which registers?
  75    These apply to the corresponding SET requests as well.  */
  76 #define NUM_GREGS (18)
  77 #define MAX_NUM_REGS (NUM_GREGS + 11)
  78
  79 static int
  80 getregs_supplies (int regno)
  81 {
  82   return 0 <= regno && regno < NUM_GREGS;
  83 }
  84
  85 static int
  86 getfpregs_supplies (int regno)
  87 {
  88   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  89 }
  90
  91 /* Does the current host support the GETREGS request?  */
  92 static int have_ptrace_getregs =
  93 #ifdef HAVE_PTRACE_GETREGS
  94   1
  95 #else
  96   0
  97 #endif
  98 ;
  99
 100 \f
 101
 102 /* Fetching registers directly from the U area, one at a time.  */
 103
 104 /* Fetch one register.  */
 105
 106 static void
 107 fetch_register (struct regcache *regcache, int regno)
 108 {
 109   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 110   long regaddr, val;
 111   int i;
 112   gdb_byte buf[MAX_REGISTER_SIZE];
 113   int tid;
 114
 115   /* Overload thread id onto process id.  */
 116   tid = TIDGET (inferior_ptid);
 117   if (tid == 0)
 118     tid = PIDGET (inferior_ptid);       /* no thread id, just use
 119                                            process id.  */
 120
 121   regaddr = 4 * regmap[regno];
 122   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 123     {
 124       errno = 0;
 125       val = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 126       memcpy (&buf[i], &val, sizeof (long));
 127       regaddr += sizeof (long);
 128       if (errno != 0)
 129         error (_("Couldn't read register %s (#%d): %s."),
 130                gdbarch_register_name (gdbarch, regno),
 131                regno, safe_strerror (errno));
 132     }
 133   regcache_raw_supply (regcache, regno, buf);
 134 }
 135
 136 /* Fetch register values from the inferior.
 137    If REGNO is negative, do this for all registers.
 138    Otherwise, REGNO specifies which register (so we can save time).  */
 139
 140 static void
 141 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 142 {
 143   if (regno >= 0)
 144     {
 145       fetch_register (regcache, regno);
 146     }
 147   else
 148     {
 149       for (regno = 0;
 150            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 151            regno++)
 152         {
 153           fetch_register (regcache, regno);
 154         }
 155     }
 156 }
 157
 158 /* Store one register.  */
 159
 160 static void
 161 store_register (const struct regcache *regcache, int regno)
 162 {
 163   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 164   long regaddr, val;
 165   int i;
 166   int tid;
 167   gdb_byte buf[MAX_REGISTER_SIZE];
 168
 169   /* Overload thread id onto process id.  */
 170   tid = TIDGET (inferior_ptid);
 171   if (tid == 0)
 172     tid = PIDGET (inferior_ptid);       /* no thread id, just use
 173                                            process id.  */
 174
 175   regaddr = 4 * regmap[regno];
 176
 177   /* Put the contents of regno into a local buffer.  */
 178   regcache_raw_collect (regcache, regno, buf);
 179
 180   /* Store the local buffer into the inferior a chunk at the time.  */
 181   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 182     {
 183       errno = 0;
 184       memcpy (&val, &buf[i], sizeof (long));
 185       ptrace (PTRACE_POKEUSER, tid, regaddr, val);
 186       regaddr += sizeof (long);
 187       if (errno != 0)
 188         error (_("Couldn't write register %s (#%d): %s."),
 189                gdbarch_register_name (gdbarch, regno),
 190                regno, safe_strerror (errno));
 191     }
 192 }
 193
 194 /* Store our register values back into the inferior.
 195    If REGNO is negative, do this for all registers.
 196    Otherwise, REGNO specifies which register (so we can save time).  */
 197
 198 static void
 199 old_store_inferior_registers (const struct regcache *regcache, int regno)
 200 {
 201   if (regno >= 0)
 202     {
 203       store_register (regcache, regno);
 204     }
 205   else
 206     {
 207       for (regno = 0;
 208            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 209            regno++)
 210         {
 211           store_register (regcache, regno);
 212         }
 213     }
 214 }
 215 \f
 216 /*  Given a pointer to a general register set in /proc format
 217    (elf_gregset_t *), unpack the register contents and supply
 218    them as gdb's idea of the current register values.  */
 219
 220 void
 221 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 222 {
 223   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 224   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 225   int regi;
 226
 227   for (regi = M68K_D0_REGNUM;
 228        regi <= gdbarch_sp_regnum (gdbarch);
 229        regi++)
 230     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 231   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 232                        &regp[PT_SR]);
 233   regcache_raw_supply (regcache,
 234                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 235 }
 236
 237 /* Fill register REGNO (if it is a general-purpose register) in
 238    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 239    do this for all registers.  */
 240 void
 241 fill_gregset (const struct regcache *regcache,
 242               elf_gregset_t *gregsetp, int regno)
 243 {
 244   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 245   int i;
 246
 247   for (i = 0; i < NUM_GREGS; i++)
 248     if (regno == -1 || regno == i)
 249       regcache_raw_collect (regcache, i, regp + regmap[i]);
 250 }
 251
 252 #ifdef HAVE_PTRACE_GETREGS
 253
 254 /* Fetch all general-purpose registers from process/thread TID and
 255    store their values in GDB's register array.  */
 256
 257 static void
 258 fetch_regs (struct regcache *regcache, int tid)
 259 {
 260   elf_gregset_t regs;
 261
 262   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 263     {
 264       if (errno == EIO)
 265         {
 266           /* The kernel we're running on doesn't support the GETREGS
 267              request.  Reset `have_ptrace_getregs'.  */
 268           have_ptrace_getregs = 0;
 269           return;
 270         }
 271
 272       perror_with_name (_("Couldn't get registers"));
 273     }
 274
 275   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 276 }
 277
 278 /* Store all valid general-purpose registers in GDB's register array
 279    into the process/thread specified by TID.  */
 280
 281 static void
 282 store_regs (const struct regcache *regcache, int tid, int regno)
 283 {
 284   elf_gregset_t regs;
 285
 286   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 287     perror_with_name (_("Couldn't get registers"));
 288
 289   fill_gregset (regcache, &regs, regno);
 290
 291   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 292     perror_with_name (_("Couldn't write registers"));
 293 }
 294
 295 #else
 296
 297 static void fetch_regs (struct regcache *regcache, int tid)
 298 {
 299 }
 300
 301 static void store_regs (const struct regcache *regcache, int tid, int regno)
 302 {
 303 }
 304
 305 #endif
 306
 307 \f
 308 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 309
 310 /* What is the address of fpN within the floating-point register set F?  */
 311 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 312
 313 /* Fill GDB's register array with the floating-point register values in
 314    *FPREGSETP.  */
 315
 316 void
 317 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 318 {
 319   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 320   int regi;
 321
 322   for (regi = gdbarch_fp0_regnum (gdbarch);
 323        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 324     regcache_raw_supply (regcache, regi,
 325                          FPREG_ADDR (fpregsetp,
 326                                      regi - gdbarch_fp0_regnum (gdbarch)));
 327   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 328   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 329   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 330 }
 331
 332 /* Fill register REGNO (if it is a floating-point register) in
 333    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 334    do this for all registers.  */
 335
 336 void
 337 fill_fpregset (const struct regcache *regcache,
 338                elf_fpregset_t *fpregsetp, int regno)
 339 {
 340   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 341   int i;
 342
 343   /* Fill in the floating-point registers.  */
 344   for (i = gdbarch_fp0_regnum (gdbarch);
 345        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 346     if (regno == -1 || regno == i)
 347       regcache_raw_collect (regcache, i,
 348                             FPREG_ADDR (fpregsetp,
 349                                         i - gdbarch_fp0_regnum (gdbarch)));
 350
 351   /* Fill in the floating-point control registers.  */
 352   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 353     if (regno == -1 || regno == i)
 354       regcache_raw_collect (regcache, i,
 355                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 356 }
 357
 358 #ifdef HAVE_PTRACE_GETREGS
 359
 360 /* Fetch all floating-point registers from process/thread TID and store
 361    thier values in GDB's register array.  */
 362
 363 static void
 364 fetch_fpregs (struct regcache *regcache, int tid)
 365 {
 366   elf_fpregset_t fpregs;
 367
 368   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 369     perror_with_name (_("Couldn't get floating point status"));
 370
 371   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 372 }
 373
 374 /* Store all valid floating-point registers in GDB's register array
 375    into the process/thread specified by TID.  */
 376
 377 static void
 378 store_fpregs (const struct regcache *regcache, int tid, int regno)
 379 {
 380   elf_fpregset_t fpregs;
 381
 382   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 383     perror_with_name (_("Couldn't get floating point status"));
 384
 385   fill_fpregset (regcache, &fpregs, regno);
 386
 387   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 388     perror_with_name (_("Couldn't write floating point status"));
 389 }
 390
 391 #else
 392
 393 static void fetch_fpregs (struct regcache *regcache, int tid)
 394 {
 395 }
 396
 397 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 398 {
 399 }
 400
 401 #endif
 402 \f
 403 /* Transferring arbitrary registers between GDB and inferior.  */
 404
 405 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 406    this for all registers (including the floating point and SSE
 407    registers).  */
 408
 409 static void
 410 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 411                                      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 target_ops *ops,
 468                                      struct regcache *regcache, int regno)
 469 {
 470   int tid;
 471
 472   /* Use the old method of poking around in `struct user' if the
 473      SETREGS request isn't available.  */
 474   if (! have_ptrace_getregs)
 475     {
 476       old_store_inferior_registers (regcache, regno);
 477       return;
 478     }
 479
 480   /* GNU/Linux LWP ID's are process ID's.  */
 481   tid = TIDGET (inferior_ptid);
 482   if (tid == 0)
 483     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 484
 485   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 486      transfers more registers in one system call.  But remember that
 487      store_fpregs can fail, and return zero.  */
 488   if (regno == -1)
 489     {
 490       store_regs (regcache, tid, regno);
 491       store_fpregs (regcache, tid, regno);
 492       return;
 493     }
 494
 495   if (getregs_supplies (regno))
 496     {
 497       store_regs (regcache, tid, regno);
 498       return;
 499     }
 500
 501   if (getfpregs_supplies (regno))
 502     {
 503       store_fpregs (regcache, tid, regno);
 504       return;
 505     }
 506
 507   internal_error (__FILE__, __LINE__,
 508                   _("Got request to store bad register number %d."), regno);
 509 }
 510 \f
 511 /* Interpreting register set info found in core files.  */
 512
 513 /* Provide registers to GDB from a core file.
 514
 515    (We can't use the generic version of this function in
 516    core-regset.c, because we need to use elf_gregset_t instead of
 517    gregset_t.)
 518
 519    CORE_REG_SECT points to an array of bytes, which are the contents
 520    of a `note' from a core file which BFD thinks might contain
 521    register contents.  CORE_REG_SIZE is its size.
 522
 523    WHICH says which register set corelow suspects this is:
 524      0 --- the general-purpose register set, in elf_gregset_t format
 525      2 --- the floating-point register set, in elf_fpregset_t format
 526
 527    REG_ADDR isn't used on GNU/Linux.  */
 528
 529 static void
 530 fetch_core_registers (struct regcache *regcache,
 531                       char *core_reg_sect, unsigned core_reg_size,
 532                       int which, CORE_ADDR reg_addr)
 533 {
 534   elf_gregset_t gregset;
 535   elf_fpregset_t fpregset;
 536
 537   switch (which)
 538     {
 539     case 0:
 540       if (core_reg_size != sizeof (gregset))
 541         warning (_("Wrong size gregset in core file."));
 542       else
 543         {
 544           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 545           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 546         }
 547       break;
 548
 549     case 2:
 550       if (core_reg_size != sizeof (fpregset))
 551         warning (_("Wrong size fpregset in core file."));
 552       else
 553         {
 554           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 555           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 556         }
 557       break;
 558
 559     default:
 560       /* We've covered all the kinds of registers we know about here,
 561          so this must be something we wouldn't know what to do with
 562          anyway.  Just ignore it.  */
 563       break;
 564     }
 565 }
 566 \f
 567
 568 /* Fetch the thread-local storage pointer for libthread_db.  */
 569
 570 ps_err_e
 571 ps_get_thread_area (const struct ps_prochandle *ph,
 572                     lwpid_t lwpid, int idx, void **base)
 573 {
 574   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) < 0)
 575     return PS_ERR;
 576
 577   /* IDX is the bias from the thread pointer to the beginning of the
 578      thread descriptor.  It has to be subtracted due to implementation
 579      quirks in libthread_db.  */
 580   *base = (char *) *base - idx;
 581
 582   return PS_OK;
 583 }
 584 \f
 585
 586 /* Register that we are able to handle GNU/Linux ELF core file
 587    formats.  */
 588
 589 static struct core_fns linux_elf_core_fns =
 590 {
 591   bfd_target_elf_flavour,               /* core_flavour */
 592   default_check_format,                 /* check_format */
 593   default_core_sniffer,                 /* core_sniffer */
 594   fetch_core_registers,                 /* core_read_registers */
 595   NULL                                  /* next */
 596 };
 597
 598 void _initialize_m68k_linux_nat (void);
 599
 600 void
 601 _initialize_m68k_linux_nat (void)
 602 {
 603   struct target_ops *t;
 604
 605   /* Fill in the generic GNU/Linux methods.  */
 606   t = linux_target ();
 607
 608   /* Add our register access methods.  */
 609   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 610   t->to_store_registers = m68k_linux_store_inferior_registers;
 611
 612   /* Register the target.  */
 613   linux_nat_add_target (t);
 614
 615   deprecated_add_core_fns (&linux_elf_core_fns);
 616 }