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 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 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 process id */
 165
 166   regaddr = 4 * regmap[regno];
 167
 168   /* Put the contents of regno into a local buffer */
 169   regcache_raw_collect (regcache, regno, buf);
 170
 171   /* Store the local buffer into the inferior a chunk at the time. */
 172   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 173     {
 174       errno = 0;
 175       ptrace (PTRACE_POKEUSER, tid, regaddr, *(long *) &buf[i]);
 176       regaddr += sizeof (long);
 177       if (errno != 0)
 178         error (_("Couldn't write register %s (#%d): %s."),
 179                gdbarch_register_name (gdbarch, regno),
 180                regno, safe_strerror (errno));
 181     }
 182 }
 183
 184 /* Store our register values back into the inferior.
 185    If REGNO is negative, do this for all registers.
 186    Otherwise, REGNO specifies which register (so we can save time).  */
 187
 188 static void
 189 old_store_inferior_registers (const struct regcache *regcache, int regno)
 190 {
 191   if (regno >= 0)
 192     {
 193       store_register (regcache, regno);
 194     }
 195   else
 196     {
 197       for (regno = 0;
 198            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 199            regno++)
 200         {
 201           store_register (regcache, regno);
 202         }
 203     }
 204 }
 205 \f
 206 /*  Given a pointer to a general register set in /proc format
 207    (elf_gregset_t *), unpack the register contents and supply
 208    them as gdb's idea of the current register values. */
 209
 210 void
 211 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 212 {
 213   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 214   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 215   int regi;
 216
 217   for (regi = M68K_D0_REGNUM;
 218        regi <= gdbarch_sp_regnum (gdbarch);
 219        regi++)
 220     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 221   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 222                        &regp[PT_SR]);
 223   regcache_raw_supply (regcache,
 224                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 225 }
 226
 227 /* Fill register REGNO (if it is a general-purpose register) in
 228    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 229    do this for all registers.  */
 230 void
 231 fill_gregset (const struct regcache *regcache,
 232               elf_gregset_t *gregsetp, int regno)
 233 {
 234   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 235   int i;
 236
 237   for (i = 0; i < NUM_GREGS; i++)
 238     if (regno == -1 || regno == i)
 239       regcache_raw_collect (regcache, i, regp + regmap[i]);
 240 }
 241
 242 #ifdef HAVE_PTRACE_GETREGS
 243
 244 /* Fetch all general-purpose registers from process/thread TID and
 245    store their values in GDB's register array.  */
 246
 247 static void
 248 fetch_regs (struct regcache *regcache, int tid)
 249 {
 250   elf_gregset_t regs;
 251
 252   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 253     {
 254       if (errno == EIO)
 255         {
 256           /* The kernel we're running on doesn't support the GETREGS
 257              request.  Reset `have_ptrace_getregs'.  */
 258           have_ptrace_getregs = 0;
 259           return;
 260         }
 261
 262       perror_with_name (_("Couldn't get registers"));
 263     }
 264
 265   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 266 }
 267
 268 /* Store all valid general-purpose registers in GDB's register array
 269    into the process/thread specified by TID.  */
 270
 271 static void
 272 store_regs (const struct regcache *regcache, int tid, int regno)
 273 {
 274   elf_gregset_t regs;
 275
 276   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 277     perror_with_name (_("Couldn't get registers"));
 278
 279   fill_gregset (regcache, &regs, regno);
 280
 281   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 282     perror_with_name (_("Couldn't write registers"));
 283 }
 284
 285 #else
 286
 287 static void fetch_regs (struct regcache *regcache, int tid) {}
 288 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 289
 290 #endif
 291
 292 \f
 293 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 294
 295 /* What is the address of fpN within the floating-point register set F?  */
 296 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 297
 298 /* Fill GDB's register array with the floating-point register values in
 299    *FPREGSETP.  */
 300
 301 void
 302 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 303 {
 304   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 305   int regi;
 306
 307   for (regi = gdbarch_fp0_regnum (gdbarch);
 308        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 309     regcache_raw_supply (regcache, regi,
 310                          FPREG_ADDR (fpregsetp,
 311                                      regi - gdbarch_fp0_regnum (gdbarch)));
 312   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 313   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 314   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 315 }
 316
 317 /* Fill register REGNO (if it is a floating-point register) in
 318    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 319    do this for all registers.  */
 320
 321 void
 322 fill_fpregset (const struct regcache *regcache,
 323                elf_fpregset_t *fpregsetp, int regno)
 324 {
 325   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 326   int i;
 327
 328   /* Fill in the floating-point registers.  */
 329   for (i = gdbarch_fp0_regnum (gdbarch);
 330        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 331     if (regno == -1 || regno == i)
 332       regcache_raw_collect (regcache, i,
 333                             FPREG_ADDR (fpregsetp,
 334                                         i - gdbarch_fp0_regnum (gdbarch)));
 335
 336   /* Fill in the floating-point control registers.  */
 337   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 338     if (regno == -1 || regno == i)
 339       regcache_raw_collect (regcache, i,
 340                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 341 }
 342
 343 #ifdef HAVE_PTRACE_GETREGS
 344
 345 /* Fetch all floating-point registers from process/thread TID and store
 346    thier values in GDB's register array.  */
 347
 348 static void
 349 fetch_fpregs (struct regcache *regcache, int tid)
 350 {
 351   elf_fpregset_t fpregs;
 352
 353   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 354     perror_with_name (_("Couldn't get floating point status"));
 355
 356   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 357 }
 358
 359 /* Store all valid floating-point registers in GDB's register array
 360    into the process/thread specified by TID.  */
 361
 362 static void
 363 store_fpregs (const struct regcache *regcache, int tid, int regno)
 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   fill_fpregset (regcache, &fpregs, regno);
 371
 372   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 373     perror_with_name (_("Couldn't write floating point status"));
 374 }
 375
 376 #else
 377
 378 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 379 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 380
 381 #endif
 382 \f
 383 /* Transferring arbitrary registers between GDB and inferior.  */
 384
 385 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 386    this for all registers (including the floating point and SSE
 387    registers).  */
 388
 389 static void
 390 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 391                                      struct regcache *regcache, int regno)
 392 {
 393   int tid;
 394
 395   /* Use the old method of peeking around in `struct user' if the
 396      GETREGS request isn't available.  */
 397   if (! have_ptrace_getregs)
 398     {
 399       old_fetch_inferior_registers (regcache, regno);
 400       return;
 401     }
 402
 403   /* GNU/Linux LWP ID's are process ID's.  */
 404   tid = TIDGET (inferior_ptid);
 405   if (tid == 0)
 406     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 407
 408   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 409      transfers more registers in one system call, and we'll cache the
 410      results.  But remember that fetch_fpxregs can fail, and return
 411      zero.  */
 412   if (regno == -1)
 413     {
 414       fetch_regs (regcache, tid);
 415
 416       /* The call above might reset `have_ptrace_getregs'.  */
 417       if (! have_ptrace_getregs)
 418         {
 419           old_fetch_inferior_registers (regcache, -1);
 420           return;
 421         }
 422
 423       fetch_fpregs (regcache, tid);
 424       return;
 425     }
 426
 427   if (getregs_supplies (regno))
 428     {
 429       fetch_regs (regcache, tid);
 430       return;
 431     }
 432
 433   if (getfpregs_supplies (regno))
 434     {
 435       fetch_fpregs (regcache, tid);
 436       return;
 437     }
 438
 439   internal_error (__FILE__, __LINE__,
 440                   _("Got request for bad register number %d."), regno);
 441 }
 442
 443 /* Store register REGNO back into the child process.  If REGNO is -1,
 444    do this for all registers (including the floating point and SSE
 445    registers).  */
 446 static void
 447 m68k_linux_store_inferior_registers (struct target_ops *ops,
 448                                      struct regcache *regcache, int regno)
 449 {
 450   int tid;
 451
 452   /* Use the old method of poking around in `struct user' if the
 453      SETREGS request isn't available.  */
 454   if (! have_ptrace_getregs)
 455     {
 456       old_store_inferior_registers (regcache, regno);
 457       return;
 458     }
 459
 460   /* GNU/Linux LWP ID's are process ID's.  */
 461   tid = TIDGET (inferior_ptid);
 462   if (tid == 0)
 463     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 464
 465   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 466      transfers more registers in one system call.  But remember that
 467      store_fpregs can fail, and return zero.  */
 468   if (regno == -1)
 469     {
 470       store_regs (regcache, tid, regno);
 471       store_fpregs (regcache, tid, regno);
 472       return;
 473     }
 474
 475   if (getregs_supplies (regno))
 476     {
 477       store_regs (regcache, tid, regno);
 478       return;
 479     }
 480
 481   if (getfpregs_supplies (regno))
 482     {
 483       store_fpregs (regcache, tid, regno);
 484       return;
 485     }
 486
 487   internal_error (__FILE__, __LINE__,
 488                   _("Got request to store bad register number %d."), regno);
 489 }
 490 \f
 491 /* Interpreting register set info found in core files.  */
 492
 493 /* Provide registers to GDB from a core file.
 494
 495    (We can't use the generic version of this function in
 496    core-regset.c, because we need to use elf_gregset_t instead of
 497    gregset_t.)
 498
 499    CORE_REG_SECT points to an array of bytes, which are the contents
 500    of a `note' from a core file which BFD thinks might contain
 501    register contents.  CORE_REG_SIZE is its size.
 502
 503    WHICH says which register set corelow suspects this is:
 504      0 --- the general-purpose register set, in elf_gregset_t format
 505      2 --- the floating-point register set, in elf_fpregset_t format
 506
 507    REG_ADDR isn't used on GNU/Linux.  */
 508
 509 static void
 510 fetch_core_registers (struct regcache *regcache,
 511                       char *core_reg_sect, unsigned core_reg_size,
 512                       int which, CORE_ADDR reg_addr)
 513 {
 514   elf_gregset_t gregset;
 515   elf_fpregset_t fpregset;
 516
 517   switch (which)
 518     {
 519     case 0:
 520       if (core_reg_size != sizeof (gregset))
 521         warning (_("Wrong size gregset in core file."));
 522       else
 523         {
 524           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 525           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 526         }
 527       break;
 528
 529     case 2:
 530       if (core_reg_size != sizeof (fpregset))
 531         warning (_("Wrong size fpregset in core file."));
 532       else
 533         {
 534           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 535           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 536         }
 537       break;
 538
 539     default:
 540       /* We've covered all the kinds of registers we know about here,
 541          so this must be something we wouldn't know what to do with
 542          anyway.  Just ignore it.  */
 543       break;
 544     }
 545 }
 546 \f
 547
 548 /* Register that we are able to handle GNU/Linux ELF core file
 549    formats.  */
 550
 551 static struct core_fns linux_elf_core_fns =
 552 {
 553   bfd_target_elf_flavour,               /* core_flavour */
 554   default_check_format,                 /* check_format */
 555   default_core_sniffer,                 /* core_sniffer */
 556   fetch_core_registers,                 /* core_read_registers */
 557   NULL                                  /* next */
 558 };
 559
 560 void _initialize_m68k_linux_nat (void);
 561
 562 void
 563 _initialize_m68k_linux_nat (void)
 564 {
 565   struct target_ops *t;
 566
 567   /* Fill in the generic GNU/Linux methods.  */
 568   t = linux_target ();
 569
 570   /* Add our register access methods.  */
 571   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 572   t->to_store_registers = m68k_linux_store_inferior_registers;
 573
 574   /* Register the target.  */
 575   linux_nat_add_target (t);
 576
 577   deprecated_add_core_fns (&linux_elf_core_fns);
 578 }