gdb/m68klinux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright (C) 1996-2014 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 <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 <sys/stat.h>
  46
  47 #include "floatformat.h"
  48
  49 /* Prototypes for supply_gregset etc.  */
  50 #include "gregset.h"
  51
  52 /* Defines ps_err_e, struct ps_prochandle.  */
  53 #include "gdb_proc_service.h"
  54
  55 #ifndef PTRACE_GET_THREAD_AREA
  56 #define PTRACE_GET_THREAD_AREA 25
  57 #endif
  58 \f
  59 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  60 static const int regmap[] =
  61 {
  62   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  63   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  64   PT_SR, PT_PC,
  65   /* PT_FP0, ..., PT_FP7 */
  66   21, 24, 27, 30, 33, 36, 39, 42,
  67   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  68   45, 46, 47
  69 };
  70
  71 /* Which ptrace request retrieves which registers?
  72    These apply to the corresponding SET requests as well.  */
  73 #define NUM_GREGS (18)
  74 #define MAX_NUM_REGS (NUM_GREGS + 11)
  75
  76 static int
  77 getregs_supplies (int regno)
  78 {
  79   return 0 <= regno && regno < NUM_GREGS;
  80 }
  81
  82 static int
  83 getfpregs_supplies (int regno)
  84 {
  85   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  86 }
  87
  88 /* Does the current host support the GETREGS request?  */
  89 static int have_ptrace_getregs =
  90 #ifdef HAVE_PTRACE_GETREGS
  91   1
  92 #else
  93   0
  94 #endif
  95 ;
  96
  97 \f
  98
  99 /* Fetching registers directly from the U area, one at a time.  */
 100
 101 /* Fetch one register.  */
 102
 103 static void
 104 fetch_register (struct regcache *regcache, int regno)
 105 {
 106   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 107   long regaddr, val;
 108   int i;
 109   gdb_byte buf[MAX_REGISTER_SIZE];
 110   int tid;
 111
 112   /* Overload thread id onto process id.  */
 113   tid = ptid_get_lwp (inferior_ptid);
 114   if (tid == 0)
 115     tid = ptid_get_pid (inferior_ptid); /* no thread id, just use
 116                                            process id.  */
 117
 118   regaddr = 4 * regmap[regno];
 119   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 120     {
 121       errno = 0;
 122       val = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 123       memcpy (&buf[i], &val, sizeof (long));
 124       regaddr += sizeof (long);
 125       if (errno != 0)
 126         error (_("Couldn't read register %s (#%d): %s."),
 127                gdbarch_register_name (gdbarch, regno),
 128                regno, safe_strerror (errno));
 129     }
 130   regcache_raw_supply (regcache, regno, buf);
 131 }
 132
 133 /* Fetch register values from the inferior.
 134    If REGNO is negative, do this for all registers.
 135    Otherwise, REGNO specifies which register (so we can save time).  */
 136
 137 static void
 138 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 139 {
 140   if (regno >= 0)
 141     {
 142       fetch_register (regcache, regno);
 143     }
 144   else
 145     {
 146       for (regno = 0;
 147            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 148            regno++)
 149         {
 150           fetch_register (regcache, regno);
 151         }
 152     }
 153 }
 154
 155 /* Store one register.  */
 156
 157 static void
 158 store_register (const struct regcache *regcache, int regno)
 159 {
 160   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 161   long regaddr, val;
 162   int i;
 163   int tid;
 164   gdb_byte buf[MAX_REGISTER_SIZE];
 165
 166   /* Overload thread id onto process id.  */
 167   tid = ptid_get_lwp (inferior_ptid);
 168   if (tid == 0)
 169     tid = ptid_get_pid (inferior_ptid); /* no thread id, just use
 170                                            process id.  */
 171
 172   regaddr = 4 * regmap[regno];
 173
 174   /* Put the contents of regno into a local buffer.  */
 175   regcache_raw_collect (regcache, regno, buf);
 176
 177   /* Store the local buffer into the inferior a chunk at the time.  */
 178   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 179     {
 180       errno = 0;
 181       memcpy (&val, &buf[i], sizeof (long));
 182       ptrace (PTRACE_POKEUSER, tid, regaddr, val);
 183       regaddr += sizeof (long);
 184       if (errno != 0)
 185         error (_("Couldn't write register %s (#%d): %s."),
 186                gdbarch_register_name (gdbarch, regno),
 187                regno, safe_strerror (errno));
 188     }
 189 }
 190
 191 /* Store our register values back into the inferior.
 192    If REGNO is negative, do this for all registers.
 193    Otherwise, REGNO specifies which register (so we can save time).  */
 194
 195 static void
 196 old_store_inferior_registers (const struct regcache *regcache, int regno)
 197 {
 198   if (regno >= 0)
 199     {
 200       store_register (regcache, regno);
 201     }
 202   else
 203     {
 204       for (regno = 0;
 205            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 206            regno++)
 207         {
 208           store_register (regcache, regno);
 209         }
 210     }
 211 }
 212 \f
 213 /*  Given a pointer to a general register set in /proc format
 214    (elf_gregset_t *), unpack the register contents and supply
 215    them as gdb's idea of the current register values.  */
 216
 217 void
 218 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 219 {
 220   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 221   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 222   int regi;
 223
 224   for (regi = M68K_D0_REGNUM;
 225        regi <= gdbarch_sp_regnum (gdbarch);
 226        regi++)
 227     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 228   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 229                        &regp[PT_SR]);
 230   regcache_raw_supply (regcache,
 231                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 232 }
 233
 234 /* Fill register REGNO (if it is a general-purpose register) in
 235    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 236    do this for all registers.  */
 237 void
 238 fill_gregset (const struct regcache *regcache,
 239               elf_gregset_t *gregsetp, int regno)
 240 {
 241   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 242   int i;
 243
 244   for (i = 0; i < NUM_GREGS; i++)
 245     if (regno == -1 || regno == i)
 246       regcache_raw_collect (regcache, i, regp + regmap[i]);
 247 }
 248
 249 #ifdef HAVE_PTRACE_GETREGS
 250
 251 /* Fetch all general-purpose registers from process/thread TID and
 252    store their values in GDB's register array.  */
 253
 254 static void
 255 fetch_regs (struct regcache *regcache, int tid)
 256 {
 257   elf_gregset_t regs;
 258
 259   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 260     {
 261       if (errno == EIO)
 262         {
 263           /* The kernel we're running on doesn't support the GETREGS
 264              request.  Reset `have_ptrace_getregs'.  */
 265           have_ptrace_getregs = 0;
 266           return;
 267         }
 268
 269       perror_with_name (_("Couldn't get registers"));
 270     }
 271
 272   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 273 }
 274
 275 /* Store all valid general-purpose registers in GDB's register array
 276    into the process/thread specified by TID.  */
 277
 278 static void
 279 store_regs (const struct regcache *regcache, int tid, int regno)
 280 {
 281   elf_gregset_t regs;
 282
 283   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 284     perror_with_name (_("Couldn't get registers"));
 285
 286   fill_gregset (regcache, &regs, regno);
 287
 288   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 289     perror_with_name (_("Couldn't write registers"));
 290 }
 291
 292 #else
 293
 294 static void fetch_regs (struct regcache *regcache, int tid)
 295 {
 296 }
 297
 298 static void store_regs (const struct regcache *regcache, int tid, int regno)
 299 {
 300 }
 301
 302 #endif
 303
 304 \f
 305 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 306
 307 /* What is the address of fpN within the floating-point register set F?  */
 308 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 309
 310 /* Fill GDB's register array with the floating-point register values in
 311    *FPREGSETP.  */
 312
 313 void
 314 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 315 {
 316   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 317   int regi;
 318
 319   for (regi = gdbarch_fp0_regnum (gdbarch);
 320        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 321     regcache_raw_supply (regcache, regi,
 322                          FPREG_ADDR (fpregsetp,
 323                                      regi - gdbarch_fp0_regnum (gdbarch)));
 324   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 325   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 326   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 327 }
 328
 329 /* Fill register REGNO (if it is a floating-point register) in
 330    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 331    do this for all registers.  */
 332
 333 void
 334 fill_fpregset (const struct regcache *regcache,
 335                elf_fpregset_t *fpregsetp, int regno)
 336 {
 337   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 338   int i;
 339
 340   /* Fill in the floating-point registers.  */
 341   for (i = gdbarch_fp0_regnum (gdbarch);
 342        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 343     if (regno == -1 || regno == i)
 344       regcache_raw_collect (regcache, i,
 345                             FPREG_ADDR (fpregsetp,
 346                                         i - gdbarch_fp0_regnum (gdbarch)));
 347
 348   /* Fill in the floating-point control registers.  */
 349   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 350     if (regno == -1 || regno == i)
 351       regcache_raw_collect (regcache, i,
 352                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 353 }
 354
 355 #ifdef HAVE_PTRACE_GETREGS
 356
 357 /* Fetch all floating-point registers from process/thread TID and store
 358    thier values in GDB's register array.  */
 359
 360 static void
 361 fetch_fpregs (struct regcache *regcache, int tid)
 362 {
 363   elf_fpregset_t fpregs;
 364
 365   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 366     perror_with_name (_("Couldn't get floating point status"));
 367
 368   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 369 }
 370
 371 /* Store all valid floating-point registers in GDB's register array
 372    into the process/thread specified by TID.  */
 373
 374 static void
 375 store_fpregs (const struct regcache *regcache, int tid, int regno)
 376 {
 377   elf_fpregset_t fpregs;
 378
 379   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 380     perror_with_name (_("Couldn't get floating point status"));
 381
 382   fill_fpregset (regcache, &fpregs, regno);
 383
 384   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 385     perror_with_name (_("Couldn't write floating point status"));
 386 }
 387
 388 #else
 389
 390 static void fetch_fpregs (struct regcache *regcache, int tid)
 391 {
 392 }
 393
 394 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 395 {
 396 }
 397
 398 #endif
 399 \f
 400 /* Transferring arbitrary registers between GDB and inferior.  */
 401
 402 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 403    this for all registers (including the floating point and SSE
 404    registers).  */
 405
 406 static void
 407 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 408                                      struct regcache *regcache, int regno)
 409 {
 410   int tid;
 411
 412   /* Use the old method of peeking around in `struct user' if the
 413      GETREGS request isn't available.  */
 414   if (! have_ptrace_getregs)
 415     {
 416       old_fetch_inferior_registers (regcache, regno);
 417       return;
 418     }
 419
 420   /* GNU/Linux LWP ID's are process ID's.  */
 421   tid = ptid_get_lwp (inferior_ptid);
 422   if (tid == 0)
 423     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 424
 425   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 426      transfers more registers in one system call, and we'll cache the
 427      results.  But remember that fetch_fpxregs can fail, and return
 428      zero.  */
 429   if (regno == -1)
 430     {
 431       fetch_regs (regcache, tid);
 432
 433       /* The call above might reset `have_ptrace_getregs'.  */
 434       if (! have_ptrace_getregs)
 435         {
 436           old_fetch_inferior_registers (regcache, -1);
 437           return;
 438         }
 439
 440       fetch_fpregs (regcache, tid);
 441       return;
 442     }
 443
 444   if (getregs_supplies (regno))
 445     {
 446       fetch_regs (regcache, tid);
 447       return;
 448     }
 449
 450   if (getfpregs_supplies (regno))
 451     {
 452       fetch_fpregs (regcache, tid);
 453       return;
 454     }
 455
 456   internal_error (__FILE__, __LINE__,
 457                   _("Got request for bad register number %d."), regno);
 458 }
 459
 460 /* Store register REGNO back into the child process.  If REGNO is -1,
 461    do this for all registers (including the floating point and SSE
 462    registers).  */
 463 static void
 464 m68k_linux_store_inferior_registers (struct target_ops *ops,
 465                                      struct regcache *regcache, int regno)
 466 {
 467   int tid;
 468
 469   /* Use the old method of poking around in `struct user' if the
 470      SETREGS request isn't available.  */
 471   if (! have_ptrace_getregs)
 472     {
 473       old_store_inferior_registers (regcache, regno);
 474       return;
 475     }
 476
 477   /* GNU/Linux LWP ID's are process ID's.  */
 478   tid = ptid_get_lwp (inferior_ptid);
 479   if (tid == 0)
 480     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 481
 482   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 483      transfers more registers in one system call.  But remember that
 484      store_fpregs can fail, and return zero.  */
 485   if (regno == -1)
 486     {
 487       store_regs (regcache, tid, regno);
 488       store_fpregs (regcache, tid, regno);
 489       return;
 490     }
 491
 492   if (getregs_supplies (regno))
 493     {
 494       store_regs (regcache, tid, regno);
 495       return;
 496     }
 497
 498   if (getfpregs_supplies (regno))
 499     {
 500       store_fpregs (regcache, tid, regno);
 501       return;
 502     }
 503
 504   internal_error (__FILE__, __LINE__,
 505                   _("Got request to store bad register number %d."), regno);
 506 }
 507 \f
 508 /* Interpreting register set info found in core files.  */
 509
 510 /* Provide registers to GDB from a core file.
 511
 512    (We can't use the generic version of this function in
 513    core-regset.c, because we need to use elf_gregset_t instead of
 514    gregset_t.)
 515
 516    CORE_REG_SECT points to an array of bytes, which are the contents
 517    of a `note' from a core file which BFD thinks might contain
 518    register contents.  CORE_REG_SIZE is its size.
 519
 520    WHICH says which register set corelow suspects this is:
 521      0 --- the general-purpose register set, in elf_gregset_t format
 522      2 --- the floating-point register set, in elf_fpregset_t format
 523
 524    REG_ADDR isn't used on GNU/Linux.  */
 525
 526 static void
 527 fetch_core_registers (struct regcache *regcache,
 528                       char *core_reg_sect, unsigned core_reg_size,
 529                       int which, CORE_ADDR reg_addr)
 530 {
 531   elf_gregset_t gregset;
 532   elf_fpregset_t fpregset;
 533
 534   switch (which)
 535     {
 536     case 0:
 537       if (core_reg_size != sizeof (gregset))
 538         warning (_("Wrong size gregset in core file."));
 539       else
 540         {
 541           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 542           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 543         }
 544       break;
 545
 546     case 2:
 547       if (core_reg_size != sizeof (fpregset))
 548         warning (_("Wrong size fpregset in core file."));
 549       else
 550         {
 551           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 552           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 553         }
 554       break;
 555
 556     default:
 557       /* We've covered all the kinds of registers we know about here,
 558          so this must be something we wouldn't know what to do with
 559          anyway.  Just ignore it.  */
 560       break;
 561     }
 562 }
 563 \f
 564
 565 /* Fetch the thread-local storage pointer for libthread_db.  */
 566
 567 ps_err_e
 568 ps_get_thread_area (const struct ps_prochandle *ph,
 569                     lwpid_t lwpid, int idx, void **base)
 570 {
 571   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) < 0)
 572     return PS_ERR;
 573
 574   /* IDX is the bias from the thread pointer to the beginning of the
 575      thread descriptor.  It has to be subtracted due to implementation
 576      quirks in libthread_db.  */
 577   *base = (char *) *base - idx;
 578
 579   return PS_OK;
 580 }
 581 \f
 582
 583 /* Register that we are able to handle GNU/Linux ELF core file
 584    formats.  */
 585
 586 static struct core_fns linux_elf_core_fns =
 587 {
 588   bfd_target_elf_flavour,               /* core_flavour */
 589   default_check_format,                 /* check_format */
 590   default_core_sniffer,                 /* core_sniffer */
 591   fetch_core_registers,                 /* core_read_registers */
 592   NULL                                  /* next */
 593 };
 594
 595 void _initialize_m68k_linux_nat (void);
 596
 597 void
 598 _initialize_m68k_linux_nat (void)
 599 {
 600   struct target_ops *t;
 601
 602   /* Fill in the generic GNU/Linux methods.  */
 603   t = linux_target ();
 604
 605   /* Add our register access methods.  */
 606   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 607   t->to_store_registers = m68k_linux_store_inferior_registers;
 608
 609   /* Register the target.  */
 610   linux_nat_add_target (t);
 611
 612   deprecated_add_core_fns (&linux_elf_core_fns);
 613 }