gdb/m68klinux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright (C) 1996, 1998, 2000-2012 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 \f
  55 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  56 static const int regmap[] =
  57 {
  58   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  59   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  60   PT_SR, PT_PC,
  61   /* PT_FP0, ..., PT_FP7 */
  62   21, 24, 27, 30, 33, 36, 39, 42,
  63   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  64   45, 46, 47
  65 };
  66
  67 /* Which ptrace request retrieves which registers?
  68    These apply to the corresponding SET requests as well.  */
  69 #define NUM_GREGS (18)
  70 #define MAX_NUM_REGS (NUM_GREGS + 11)
  71
  72 int
  73 getregs_supplies (int regno)
  74 {
  75   return 0 <= regno && regno < NUM_GREGS;
  76 }
  77
  78 int
  79 getfpregs_supplies (int regno)
  80 {
  81   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  82 }
  83
  84 /* Does the current host support the GETREGS request?  */
  85 int have_ptrace_getregs =
  86 #ifdef HAVE_PTRACE_GETREGS
  87   1
  88 #else
  89   0
  90 #endif
  91 ;
  92
  93 \f
  94
  95 /* Fetching registers directly from the U area, one at a time.  */
  96
  97 /* Fetch one register.  */
  98
  99 static void
 100 fetch_register (struct regcache *regcache, int regno)
 101 {
 102   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 103   long regaddr;
 104   int i;
 105   char buf[MAX_REGISTER_SIZE];
 106   int tid;
 107
 108   /* Overload thread id onto process id.  */
 109   tid = TIDGET (inferior_ptid);
 110   if (tid == 0)
 111     tid = PIDGET (inferior_ptid);       /* no thread id, just use
 112                                            process id.  */
 113
 114   regaddr = 4 * regmap[regno];
 115   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 116     {
 117       errno = 0;
 118       *(long *) &buf[i] = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 119       regaddr += sizeof (long);
 120       if (errno != 0)
 121         error (_("Couldn't read register %s (#%d): %s."),
 122                gdbarch_register_name (gdbarch, regno),
 123                regno, safe_strerror (errno));
 124     }
 125   regcache_raw_supply (regcache, regno, buf);
 126 }
 127
 128 /* Fetch register values from the inferior.
 129    If REGNO is negative, do this for all registers.
 130    Otherwise, REGNO specifies which register (so we can save time).  */
 131
 132 static void
 133 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 134 {
 135   if (regno >= 0)
 136     {
 137       fetch_register (regcache, regno);
 138     }
 139   else
 140     {
 141       for (regno = 0;
 142            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 143            regno++)
 144         {
 145           fetch_register (regcache, regno);
 146         }
 147     }
 148 }
 149
 150 /* Store one register.  */
 151
 152 static void
 153 store_register (const struct regcache *regcache, int regno)
 154 {
 155   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 156   long regaddr;
 157   int i;
 158   int tid;
 159   char buf[MAX_REGISTER_SIZE];
 160
 161   /* Overload thread id onto process id.  */
 162   tid = TIDGET (inferior_ptid);
 163   if (tid == 0)
 164     tid = PIDGET (inferior_ptid);       /* no thread id, just use
 165                                            process id.  */
 166
 167   regaddr = 4 * regmap[regno];
 168
 169   /* Put the contents of regno into a local buffer.  */
 170   regcache_raw_collect (regcache, regno, buf);
 171
 172   /* Store the local buffer into the inferior a chunk at the time.  */
 173   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 174     {
 175       errno = 0;
 176       ptrace (PTRACE_POKEUSER, tid, regaddr, *(long *) &buf[i]);
 177       regaddr += sizeof (long);
 178       if (errno != 0)
 179         error (_("Couldn't write register %s (#%d): %s."),
 180                gdbarch_register_name (gdbarch, regno),
 181                regno, safe_strerror (errno));
 182     }
 183 }
 184
 185 /* Store our register values back into the inferior.
 186    If REGNO is negative, do this for all registers.
 187    Otherwise, REGNO specifies which register (so we can save time).  */
 188
 189 static void
 190 old_store_inferior_registers (const struct regcache *regcache, int regno)
 191 {
 192   if (regno >= 0)
 193     {
 194       store_register (regcache, regno);
 195     }
 196   else
 197     {
 198       for (regno = 0;
 199            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 200            regno++)
 201         {
 202           store_register (regcache, regno);
 203         }
 204     }
 205 }
 206 \f
 207 /*  Given a pointer to a general register set in /proc format
 208    (elf_gregset_t *), unpack the register contents and supply
 209    them as gdb's idea of the current register values.  */
 210
 211 void
 212 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 213 {
 214   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 215   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 216   int regi;
 217
 218   for (regi = M68K_D0_REGNUM;
 219        regi <= gdbarch_sp_regnum (gdbarch);
 220        regi++)
 221     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 222   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 223                        &regp[PT_SR]);
 224   regcache_raw_supply (regcache,
 225                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 226 }
 227
 228 /* Fill register REGNO (if it is a general-purpose register) in
 229    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 230    do this for all registers.  */
 231 void
 232 fill_gregset (const struct regcache *regcache,
 233               elf_gregset_t *gregsetp, int regno)
 234 {
 235   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 236   int i;
 237
 238   for (i = 0; i < NUM_GREGS; i++)
 239     if (regno == -1 || regno == i)
 240       regcache_raw_collect (regcache, i, regp + regmap[i]);
 241 }
 242
 243 #ifdef HAVE_PTRACE_GETREGS
 244
 245 /* Fetch all general-purpose registers from process/thread TID and
 246    store their values in GDB's register array.  */
 247
 248 static void
 249 fetch_regs (struct regcache *regcache, int tid)
 250 {
 251   elf_gregset_t regs;
 252
 253   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 254     {
 255       if (errno == EIO)
 256         {
 257           /* The kernel we're running on doesn't support the GETREGS
 258              request.  Reset `have_ptrace_getregs'.  */
 259           have_ptrace_getregs = 0;
 260           return;
 261         }
 262
 263       perror_with_name (_("Couldn't get registers"));
 264     }
 265
 266   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 267 }
 268
 269 /* Store all valid general-purpose registers in GDB's register array
 270    into the process/thread specified by TID.  */
 271
 272 static void
 273 store_regs (const struct regcache *regcache, int tid, int regno)
 274 {
 275   elf_gregset_t regs;
 276
 277   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 278     perror_with_name (_("Couldn't get registers"));
 279
 280   fill_gregset (regcache, &regs, regno);
 281
 282   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 283     perror_with_name (_("Couldn't write registers"));
 284 }
 285
 286 #else
 287
 288 static void fetch_regs (struct regcache *regcache, int tid)
 289 {
 290 }
 291
 292 static void store_regs (const struct regcache *regcache, int tid, int regno)
 293 {
 294 }
 295
 296 #endif
 297
 298 \f
 299 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 300
 301 /* What is the address of fpN within the floating-point register set F?  */
 302 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 303
 304 /* Fill GDB's register array with the floating-point register values in
 305    *FPREGSETP.  */
 306
 307 void
 308 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 309 {
 310   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 311   int regi;
 312
 313   for (regi = gdbarch_fp0_regnum (gdbarch);
 314        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 315     regcache_raw_supply (regcache, regi,
 316                          FPREG_ADDR (fpregsetp,
 317                                      regi - gdbarch_fp0_regnum (gdbarch)));
 318   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 319   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 320   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 321 }
 322
 323 /* Fill register REGNO (if it is a floating-point register) in
 324    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 325    do this for all registers.  */
 326
 327 void
 328 fill_fpregset (const struct regcache *regcache,
 329                elf_fpregset_t *fpregsetp, int regno)
 330 {
 331   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 332   int i;
 333
 334   /* Fill in the floating-point registers.  */
 335   for (i = gdbarch_fp0_regnum (gdbarch);
 336        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 337     if (regno == -1 || regno == i)
 338       regcache_raw_collect (regcache, i,
 339                             FPREG_ADDR (fpregsetp,
 340                                         i - gdbarch_fp0_regnum (gdbarch)));
 341
 342   /* Fill in the floating-point control registers.  */
 343   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 344     if (regno == -1 || regno == i)
 345       regcache_raw_collect (regcache, i,
 346                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 347 }
 348
 349 #ifdef HAVE_PTRACE_GETREGS
 350
 351 /* Fetch all floating-point registers from process/thread TID and store
 352    thier values in GDB's register array.  */
 353
 354 static void
 355 fetch_fpregs (struct regcache *regcache, int tid)
 356 {
 357   elf_fpregset_t fpregs;
 358
 359   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 360     perror_with_name (_("Couldn't get floating point status"));
 361
 362   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 363 }
 364
 365 /* Store all valid floating-point registers in GDB's register array
 366    into the process/thread specified by TID.  */
 367
 368 static void
 369 store_fpregs (const struct regcache *regcache, int tid, int regno)
 370 {
 371   elf_fpregset_t fpregs;
 372
 373   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 374     perror_with_name (_("Couldn't get floating point status"));
 375
 376   fill_fpregset (regcache, &fpregs, regno);
 377
 378   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 379     perror_with_name (_("Couldn't write floating point status"));
 380 }
 381
 382 #else
 383
 384 static void fetch_fpregs (struct regcache *regcache, int tid)
 385 {
 386 }
 387
 388 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 389 {
 390 }
 391
 392 #endif
 393 \f
 394 /* Transferring arbitrary registers between GDB and inferior.  */
 395
 396 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 397    this for all registers (including the floating point and SSE
 398    registers).  */
 399
 400 static void
 401 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 402                                      struct regcache *regcache, int regno)
 403 {
 404   int tid;
 405
 406   /* Use the old method of peeking around in `struct user' if the
 407      GETREGS request isn't available.  */
 408   if (! have_ptrace_getregs)
 409     {
 410       old_fetch_inferior_registers (regcache, regno);
 411       return;
 412     }
 413
 414   /* GNU/Linux LWP ID's are process ID's.  */
 415   tid = TIDGET (inferior_ptid);
 416   if (tid == 0)
 417     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 418
 419   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 420      transfers more registers in one system call, and we'll cache the
 421      results.  But remember that fetch_fpxregs can fail, and return
 422      zero.  */
 423   if (regno == -1)
 424     {
 425       fetch_regs (regcache, tid);
 426
 427       /* The call above might reset `have_ptrace_getregs'.  */
 428       if (! have_ptrace_getregs)
 429         {
 430           old_fetch_inferior_registers (regcache, -1);
 431           return;
 432         }
 433
 434       fetch_fpregs (regcache, tid);
 435       return;
 436     }
 437
 438   if (getregs_supplies (regno))
 439     {
 440       fetch_regs (regcache, tid);
 441       return;
 442     }
 443
 444   if (getfpregs_supplies (regno))
 445     {
 446       fetch_fpregs (regcache, tid);
 447       return;
 448     }
 449
 450   internal_error (__FILE__, __LINE__,
 451                   _("Got request for bad register number %d."), regno);
 452 }
 453
 454 /* Store register REGNO back into the child process.  If REGNO is -1,
 455    do this for all registers (including the floating point and SSE
 456    registers).  */
 457 static void
 458 m68k_linux_store_inferior_registers (struct target_ops *ops,
 459                                      struct regcache *regcache, int regno)
 460 {
 461   int tid;
 462
 463   /* Use the old method of poking around in `struct user' if the
 464      SETREGS request isn't available.  */
 465   if (! have_ptrace_getregs)
 466     {
 467       old_store_inferior_registers (regcache, regno);
 468       return;
 469     }
 470
 471   /* GNU/Linux LWP ID's are process ID's.  */
 472   tid = TIDGET (inferior_ptid);
 473   if (tid == 0)
 474     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 475
 476   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 477      transfers more registers in one system call.  But remember that
 478      store_fpregs can fail, and return zero.  */
 479   if (regno == -1)
 480     {
 481       store_regs (regcache, tid, regno);
 482       store_fpregs (regcache, tid, regno);
 483       return;
 484     }
 485
 486   if (getregs_supplies (regno))
 487     {
 488       store_regs (regcache, tid, regno);
 489       return;
 490     }
 491
 492   if (getfpregs_supplies (regno))
 493     {
 494       store_fpregs (regcache, tid, regno);
 495       return;
 496     }
 497
 498   internal_error (__FILE__, __LINE__,
 499                   _("Got request to store bad register number %d."), regno);
 500 }
 501 \f
 502 /* Interpreting register set info found in core files.  */
 503
 504 /* Provide registers to GDB from a core file.
 505
 506    (We can't use the generic version of this function in
 507    core-regset.c, because we need to use elf_gregset_t instead of
 508    gregset_t.)
 509
 510    CORE_REG_SECT points to an array of bytes, which are the contents
 511    of a `note' from a core file which BFD thinks might contain
 512    register contents.  CORE_REG_SIZE is its size.
 513
 514    WHICH says which register set corelow suspects this is:
 515      0 --- the general-purpose register set, in elf_gregset_t format
 516      2 --- the floating-point register set, in elf_fpregset_t format
 517
 518    REG_ADDR isn't used on GNU/Linux.  */
 519
 520 static void
 521 fetch_core_registers (struct regcache *regcache,
 522                       char *core_reg_sect, unsigned core_reg_size,
 523                       int which, CORE_ADDR reg_addr)
 524 {
 525   elf_gregset_t gregset;
 526   elf_fpregset_t fpregset;
 527
 528   switch (which)
 529     {
 530     case 0:
 531       if (core_reg_size != sizeof (gregset))
 532         warning (_("Wrong size gregset in core file."));
 533       else
 534         {
 535           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 536           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 537         }
 538       break;
 539
 540     case 2:
 541       if (core_reg_size != sizeof (fpregset))
 542         warning (_("Wrong size fpregset in core file."));
 543       else
 544         {
 545           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 546           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 547         }
 548       break;
 549
 550     default:
 551       /* We've covered all the kinds of registers we know about here,
 552          so this must be something we wouldn't know what to do with
 553          anyway.  Just ignore it.  */
 554       break;
 555     }
 556 }
 557 \f
 558
 559 /* Register that we are able to handle GNU/Linux ELF core file
 560    formats.  */
 561
 562 static struct core_fns linux_elf_core_fns =
 563 {
 564   bfd_target_elf_flavour,               /* core_flavour */
 565   default_check_format,                 /* check_format */
 566   default_core_sniffer,                 /* core_sniffer */
 567   fetch_core_registers,                 /* core_read_registers */
 568   NULL                                  /* next */
 569 };
 570
 571 void _initialize_m68k_linux_nat (void);
 572
 573 void
 574 _initialize_m68k_linux_nat (void)
 575 {
 576   struct target_ops *t;
 577
 578   /* Fill in the generic GNU/Linux methods.  */
 579   t = linux_target ();
 580
 581   /* Add our register access methods.  */
 582   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 583   t->to_store_registers = m68k_linux_store_inferior_registers;
 584
 585   /* Register the target.  */
 586   linux_nat_add_target (t);
 587
 588   deprecated_add_core_fns (&linux_elf_core_fns);
 589 }