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/dir.h>
  33 #include <signal.h>
  34 #include <sys/ptrace.h>
  35 #include <sys/user.h>
  36 #include <sys/ioctl.h>
  37 #include <fcntl.h>
  38 #include <sys/procfs.h>
  39
  40 #ifdef HAVE_SYS_REG_H
  41 #include <sys/reg.h>
  42 #endif
  43
  44 #include <sys/file.h>
  45 #include "gdb_stat.h"
  46
  47 #include "floatformat.h"
  48
  49 #include "target.h"
  50
  51 /* Prototypes for supply_gregset etc.  */
  52 #include "gregset.h"
  53
  54 /* Defines ps_err_e, struct ps_prochandle.  */
  55 #include "gdb_proc_service.h"
  56
  57 #ifndef PTRACE_GET_THREAD_AREA
  58 #define PTRACE_GET_THREAD_AREA 25
  59 #endif
  60 \f
  61 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  62 static const int regmap[] =
  63 {
  64   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  65   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  66   PT_SR, PT_PC,
  67   /* PT_FP0, ..., PT_FP7 */
  68   21, 24, 27, 30, 33, 36, 39, 42,
  69   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  70   45, 46, 47
  71 };
  72
  73 /* Which ptrace request retrieves which registers?
  74    These apply to the corresponding SET requests as well.  */
  75 #define NUM_GREGS (18)
  76 #define MAX_NUM_REGS (NUM_GREGS + 11)
  77
  78 static int
  79 getregs_supplies (int regno)
  80 {
  81   return 0 <= regno && regno < NUM_GREGS;
  82 }
  83
  84 static int
  85 getfpregs_supplies (int regno)
  86 {
  87   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  88 }
  89
  90 /* Does the current host support the GETREGS request?  */
  91 static int have_ptrace_getregs =
  92 #ifdef HAVE_PTRACE_GETREGS
  93   1
  94 #else
  95   0
  96 #endif
  97 ;
  98
  99 \f
 100
 101 /* Fetching registers directly from the U area, one at a time.  */
 102
 103 /* Fetch one register.  */
 104
 105 static void
 106 fetch_register (struct regcache *regcache, int regno)
 107 {
 108   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 109   long regaddr, val;
 110   int i;
 111   gdb_byte buf[MAX_REGISTER_SIZE];
 112   int tid;
 113
 114   /* Overload thread id onto process id.  */
 115   tid = ptid_get_lwp (inferior_ptid);
 116   if (tid == 0)
 117     tid = ptid_get_pid (inferior_ptid); /* no thread id, just use
 118                                            process id.  */
 119
 120   regaddr = 4 * regmap[regno];
 121   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 122     {
 123       errno = 0;
 124       val = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 125       memcpy (&buf[i], &val, sizeof (long));
 126       regaddr += sizeof (long);
 127       if (errno != 0)
 128         error (_("Couldn't read register %s (#%d): %s."),
 129                gdbarch_register_name (gdbarch, regno),
 130                regno, safe_strerror (errno));
 131     }
 132   regcache_raw_supply (regcache, regno, buf);
 133 }
 134
 135 /* Fetch register values from the inferior.
 136    If REGNO is negative, do this for all registers.
 137    Otherwise, REGNO specifies which register (so we can save time).  */
 138
 139 static void
 140 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 141 {
 142   if (regno >= 0)
 143     {
 144       fetch_register (regcache, regno);
 145     }
 146   else
 147     {
 148       for (regno = 0;
 149            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 150            regno++)
 151         {
 152           fetch_register (regcache, regno);
 153         }
 154     }
 155 }
 156
 157 /* Store one register.  */
 158
 159 static void
 160 store_register (const struct regcache *regcache, int regno)
 161 {
 162   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 163   long regaddr, val;
 164   int i;
 165   int tid;
 166   gdb_byte buf[MAX_REGISTER_SIZE];
 167
 168   /* Overload thread id onto process id.  */
 169   tid = ptid_get_lwp (inferior_ptid);
 170   if (tid == 0)
 171     tid = ptid_get_pid (inferior_ptid); /* no thread id, just use
 172                                            process id.  */
 173
 174   regaddr = 4 * regmap[regno];
 175
 176   /* Put the contents of regno into a local buffer.  */
 177   regcache_raw_collect (regcache, regno, buf);
 178
 179   /* Store the local buffer into the inferior a chunk at the time.  */
 180   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 181     {
 182       errno = 0;
 183       memcpy (&val, &buf[i], sizeof (long));
 184       ptrace (PTRACE_POKEUSER, tid, regaddr, val);
 185       regaddr += sizeof (long);
 186       if (errno != 0)
 187         error (_("Couldn't write register %s (#%d): %s."),
 188                gdbarch_register_name (gdbarch, regno),
 189                regno, safe_strerror (errno));
 190     }
 191 }
 192
 193 /* Store our register values back into the inferior.
 194    If REGNO is negative, do this for all registers.
 195    Otherwise, REGNO specifies which register (so we can save time).  */
 196
 197 static void
 198 old_store_inferior_registers (const struct regcache *regcache, int regno)
 199 {
 200   if (regno >= 0)
 201     {
 202       store_register (regcache, regno);
 203     }
 204   else
 205     {
 206       for (regno = 0;
 207            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 208            regno++)
 209         {
 210           store_register (regcache, regno);
 211         }
 212     }
 213 }
 214 \f
 215 /*  Given a pointer to a general register set in /proc format
 216    (elf_gregset_t *), unpack the register contents and supply
 217    them as gdb's idea of the current register values.  */
 218
 219 void
 220 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 221 {
 222   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 223   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 224   int regi;
 225
 226   for (regi = M68K_D0_REGNUM;
 227        regi <= gdbarch_sp_regnum (gdbarch);
 228        regi++)
 229     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 230   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 231                        &regp[PT_SR]);
 232   regcache_raw_supply (regcache,
 233                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 234 }
 235
 236 /* Fill register REGNO (if it is a general-purpose register) in
 237    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 238    do this for all registers.  */
 239 void
 240 fill_gregset (const struct regcache *regcache,
 241               elf_gregset_t *gregsetp, int regno)
 242 {
 243   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 244   int i;
 245
 246   for (i = 0; i < NUM_GREGS; i++)
 247     if (regno == -1 || regno == i)
 248       regcache_raw_collect (regcache, i, regp + regmap[i]);
 249 }
 250
 251 #ifdef HAVE_PTRACE_GETREGS
 252
 253 /* Fetch all general-purpose registers from process/thread TID and
 254    store their values in GDB's register array.  */
 255
 256 static void
 257 fetch_regs (struct regcache *regcache, int tid)
 258 {
 259   elf_gregset_t regs;
 260
 261   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 262     {
 263       if (errno == EIO)
 264         {
 265           /* The kernel we're running on doesn't support the GETREGS
 266              request.  Reset `have_ptrace_getregs'.  */
 267           have_ptrace_getregs = 0;
 268           return;
 269         }
 270
 271       perror_with_name (_("Couldn't get registers"));
 272     }
 273
 274   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 275 }
 276
 277 /* Store all valid general-purpose registers in GDB's register array
 278    into the process/thread specified by TID.  */
 279
 280 static void
 281 store_regs (const struct regcache *regcache, int tid, int regno)
 282 {
 283   elf_gregset_t regs;
 284
 285   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 286     perror_with_name (_("Couldn't get registers"));
 287
 288   fill_gregset (regcache, &regs, regno);
 289
 290   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 291     perror_with_name (_("Couldn't write registers"));
 292 }
 293
 294 #else
 295
 296 static void fetch_regs (struct regcache *regcache, int tid)
 297 {
 298 }
 299
 300 static void store_regs (const struct regcache *regcache, int tid, int regno)
 301 {
 302 }
 303
 304 #endif
 305
 306 \f
 307 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 308
 309 /* What is the address of fpN within the floating-point register set F?  */
 310 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 311
 312 /* Fill GDB's register array with the floating-point register values in
 313    *FPREGSETP.  */
 314
 315 void
 316 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 317 {
 318   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 319   int regi;
 320
 321   for (regi = gdbarch_fp0_regnum (gdbarch);
 322        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 323     regcache_raw_supply (regcache, regi,
 324                          FPREG_ADDR (fpregsetp,
 325                                      regi - gdbarch_fp0_regnum (gdbarch)));
 326   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 327   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 328   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 329 }
 330
 331 /* Fill register REGNO (if it is a floating-point register) in
 332    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 333    do this for all registers.  */
 334
 335 void
 336 fill_fpregset (const struct regcache *regcache,
 337                elf_fpregset_t *fpregsetp, int regno)
 338 {
 339   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 340   int i;
 341
 342   /* Fill in the floating-point registers.  */
 343   for (i = gdbarch_fp0_regnum (gdbarch);
 344        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 345     if (regno == -1 || regno == i)
 346       regcache_raw_collect (regcache, i,
 347                             FPREG_ADDR (fpregsetp,
 348                                         i - gdbarch_fp0_regnum (gdbarch)));
 349
 350   /* Fill in the floating-point control registers.  */
 351   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 352     if (regno == -1 || regno == i)
 353       regcache_raw_collect (regcache, i,
 354                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 355 }
 356
 357 #ifdef HAVE_PTRACE_GETREGS
 358
 359 /* Fetch all floating-point registers from process/thread TID and store
 360    thier values in GDB's register array.  */
 361
 362 static void
 363 fetch_fpregs (struct regcache *regcache, int tid)
 364 {
 365   elf_fpregset_t fpregs;
 366
 367   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 368     perror_with_name (_("Couldn't get floating point status"));
 369
 370   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 371 }
 372
 373 /* Store all valid floating-point registers in GDB's register array
 374    into the process/thread specified by TID.  */
 375
 376 static void
 377 store_fpregs (const struct regcache *regcache, int tid, int regno)
 378 {
 379   elf_fpregset_t fpregs;
 380
 381   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 382     perror_with_name (_("Couldn't get floating point status"));
 383
 384   fill_fpregset (regcache, &fpregs, regno);
 385
 386   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 387     perror_with_name (_("Couldn't write floating point status"));
 388 }
 389
 390 #else
 391
 392 static void fetch_fpregs (struct regcache *regcache, int tid)
 393 {
 394 }
 395
 396 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 397 {
 398 }
 399
 400 #endif
 401 \f
 402 /* Transferring arbitrary registers between GDB and inferior.  */
 403
 404 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 405    this for all registers (including the floating point and SSE
 406    registers).  */
 407
 408 static void
 409 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 410                                      struct regcache *regcache, int regno)
 411 {
 412   int tid;
 413
 414   /* Use the old method of peeking around in `struct user' if the
 415      GETREGS request isn't available.  */
 416   if (! have_ptrace_getregs)
 417     {
 418       old_fetch_inferior_registers (regcache, regno);
 419       return;
 420     }
 421
 422   /* GNU/Linux LWP ID's are process ID's.  */
 423   tid = ptid_get_lwp (inferior_ptid);
 424   if (tid == 0)
 425     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 426
 427   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 428      transfers more registers in one system call, and we'll cache the
 429      results.  But remember that fetch_fpxregs can fail, and return
 430      zero.  */
 431   if (regno == -1)
 432     {
 433       fetch_regs (regcache, tid);
 434
 435       /* The call above might reset `have_ptrace_getregs'.  */
 436       if (! have_ptrace_getregs)
 437         {
 438           old_fetch_inferior_registers (regcache, -1);
 439           return;
 440         }
 441
 442       fetch_fpregs (regcache, tid);
 443       return;
 444     }
 445
 446   if (getregs_supplies (regno))
 447     {
 448       fetch_regs (regcache, tid);
 449       return;
 450     }
 451
 452   if (getfpregs_supplies (regno))
 453     {
 454       fetch_fpregs (regcache, tid);
 455       return;
 456     }
 457
 458   internal_error (__FILE__, __LINE__,
 459                   _("Got request for bad register number %d."), regno);
 460 }
 461
 462 /* Store register REGNO back into the child process.  If REGNO is -1,
 463    do this for all registers (including the floating point and SSE
 464    registers).  */
 465 static void
 466 m68k_linux_store_inferior_registers (struct target_ops *ops,
 467                                      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 = ptid_get_lwp (inferior_ptid);
 481   if (tid == 0)
 482     tid = ptid_get_pid (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 /* Fetch the thread-local storage pointer for libthread_db.  */
 568
 569 ps_err_e
 570 ps_get_thread_area (const struct ps_prochandle *ph,
 571                     lwpid_t lwpid, int idx, void **base)
 572 {
 573   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) < 0)
 574     return PS_ERR;
 575
 576   /* IDX is the bias from the thread pointer to the beginning of the
 577      thread descriptor.  It has to be subtracted due to implementation
 578      quirks in libthread_db.  */
 579   *base = (char *) *base - idx;
 580
 581   return PS_OK;
 582 }
 583 \f
 584
 585 /* Register that we are able to handle GNU/Linux ELF core file
 586    formats.  */
 587
 588 static struct core_fns linux_elf_core_fns =
 589 {
 590   bfd_target_elf_flavour,               /* core_flavour */
 591   default_check_format,                 /* check_format */
 592   default_core_sniffer,                 /* core_sniffer */
 593   fetch_core_registers,                 /* core_read_registers */
 594   NULL                                  /* next */
 595 };
 596
 597 void _initialize_m68k_linux_nat (void);
 598
 599 void
 600 _initialize_m68k_linux_nat (void)
 601 {
 602   struct target_ops *t;
 603
 604   /* Fill in the generic GNU/Linux methods.  */
 605   t = linux_target ();
 606
 607   /* Add our register access methods.  */
 608   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 609   t->to_store_registers = m68k_linux_store_inferior_registers;
 610
 611   /* Register the target.  */
 612   linux_nat_add_target (t);
 613
 614   deprecated_add_core_fns (&linux_elf_core_fns);
 615 }