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    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 2 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, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "defs.h"
  24 #include "frame.h"
  25 #include "inferior.h"
  26 #include "language.h"
  27 #include "gdbcore.h"
  28 #include "gdb_string.h"
  29 #include "regcache.h"
  30 #include "target.h"
  31 #include "linux-nat.h"
  32
  33 #include "m68k-tdep.h"
  34
  35 #include <sys/param.h>
  36 #include <sys/dir.h>
  37 #include <signal.h>
  38 #include <sys/ptrace.h>
  39 #include <sys/user.h>
  40 #include <sys/ioctl.h>
  41 #include <fcntl.h>
  42 #include <sys/procfs.h>
  43
  44 #ifdef HAVE_SYS_REG_H
  45 #include <sys/reg.h>
  46 #endif
  47
  48 #include <sys/file.h>
  49 #include "gdb_stat.h"
  50
  51 #include "floatformat.h"
  52
  53 #include "target.h"
  54
  55 /* Prototypes for supply_gregset etc. */
  56 #include "gregset.h"
  57 \f
  58 /* This table must line up with REGISTER_NAME in "m68k-tdep.c".  */
  59 static const int regmap[] =
  60 {
  61   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  62   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  63   PT_SR, PT_PC,
  64   /* PT_FP0, ..., PT_FP7 */
  65   21, 24, 27, 30, 33, 36, 39, 42,
  66   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  67   45, 46, 47
  68 };
  69
  70 /* Which ptrace request retrieves which registers?
  71    These apply to the corresponding SET requests as well.  */
  72 #define NUM_GREGS (18)
  73 #define MAX_NUM_REGS (NUM_GREGS + 11)
  74
  75 int
  76 getregs_supplies (int regno)
  77 {
  78   return 0 <= regno && regno < NUM_GREGS;
  79 }
  80
  81 int
  82 getfpregs_supplies (int regno)
  83 {
  84   return FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  85 }
  86
  87 /* Does the current host support the GETREGS request?  */
  88 int have_ptrace_getregs =
  89 #ifdef HAVE_PTRACE_GETREGS
  90   1
  91 #else
  92   0
  93 #endif
  94 ;
  95
  96 \f
  97
  98 /* Fetching registers directly from the U area, one at a time.  */
  99
 100 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 101    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 102    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 103    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 104    fall back on that code when GDB is running on top of a kernel that
 105    doesn't support the GETREGS request.  */
 106
 107 #ifndef PT_READ_U
 108 #define PT_READ_U PTRACE_PEEKUSR
 109 #endif
 110 #ifndef PT_WRITE_U
 111 #define PT_WRITE_U PTRACE_POKEUSR
 112 #endif
 113
 114 /* Fetch one register.  */
 115
 116 static void
 117 fetch_register (struct regcache *regcache, int regno)
 118 {
 119   /* This isn't really an address.  But ptrace thinks of it as one.  */
 120   CORE_ADDR regaddr;
 121   char mess[128];               /* For messages */
 122   int i;
 123   char buf[MAX_REGISTER_SIZE];
 124   int tid;
 125
 126   if (CANNOT_FETCH_REGISTER (regno))
 127     {
 128       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 129       regcache_raw_supply (regcache, regno, buf);
 130       return;
 131     }
 132
 133   /* Overload thread id onto process id */
 134   tid = TIDGET (inferior_ptid);
 135   if (tid == 0)
 136     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 137
 138   regaddr = 4 * regmap[regno];
 139   for (i = 0; i < register_size (current_gdbarch, regno);
 140        i += sizeof (PTRACE_TYPE_RET))
 141     {
 142       errno = 0;
 143       *(PTRACE_TYPE_RET *) &buf[i] = ptrace (PT_READ_U, tid,
 144                                               (PTRACE_TYPE_ARG3) regaddr, 0);
 145       regaddr += sizeof (PTRACE_TYPE_RET);
 146       if (errno != 0)
 147         {
 148           sprintf (mess, "reading register %s (#%d)",
 149                    REGISTER_NAME (regno), regno);
 150           perror_with_name (mess);
 151         }
 152     }
 153   regcache_raw_supply (regcache, regno, buf);
 154 }
 155
 156 /* Fetch register values from the inferior.
 157    If REGNO is negative, do this for all registers.
 158    Otherwise, REGNO specifies which register (so we can save time). */
 159
 160 static void
 161 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 162 {
 163   if (regno >= 0)
 164     {
 165       fetch_register (regcache, regno);
 166     }
 167   else
 168     {
 169       for (regno = 0; regno < NUM_REGS; regno++)
 170         {
 171           fetch_register (regcache, regno);
 172         }
 173     }
 174 }
 175
 176 /* Store one register. */
 177
 178 static void
 179 store_register (const struct regcache *regcache, int regno)
 180 {
 181   /* This isn't really an address.  But ptrace thinks of it as one.  */
 182   CORE_ADDR regaddr;
 183   char mess[128];               /* For messages */
 184   int i;
 185   int tid;
 186   char buf[MAX_REGISTER_SIZE];
 187
 188   if (CANNOT_STORE_REGISTER (regno))
 189     {
 190       return;
 191     }
 192
 193   /* Overload thread id onto process id */
 194   tid = TIDGET (inferior_ptid);
 195   if (tid == 0)
 196     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 197
 198   regaddr = 4 * regmap[regno];
 199
 200   /* Put the contents of regno into a local buffer */
 201   regcache_raw_collect (regcache, regno, buf);
 202
 203   /* Store the local buffer into the inferior a chunk at the time. */
 204   for (i = 0; i < register_size (current_gdbarch, regno);
 205        i += sizeof (PTRACE_TYPE_RET))
 206     {
 207       errno = 0;
 208       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 209               *(PTRACE_TYPE_RET *) (buf + i));
 210       regaddr += sizeof (PTRACE_TYPE_RET);
 211       if (errno != 0)
 212         {
 213           sprintf (mess, "writing register %s (#%d)",
 214                    REGISTER_NAME (regno), regno);
 215           perror_with_name (mess);
 216         }
 217     }
 218 }
 219
 220 /* Store our register values back into the inferior.
 221    If REGNO is negative, do this for all registers.
 222    Otherwise, REGNO specifies which register (so we can save time).  */
 223
 224 static void
 225 old_store_inferior_registers (const struct regcache *regcache, int regno)
 226 {
 227   if (regno >= 0)
 228     {
 229       store_register (regcache, regno);
 230     }
 231   else
 232     {
 233       for (regno = 0; regno < NUM_REGS; regno++)
 234         {
 235           store_register (regcache, regno);
 236         }
 237     }
 238 }
 239 \f
 240 /*  Given a pointer to a general register set in /proc format
 241    (elf_gregset_t *), unpack the register contents and supply
 242    them as gdb's idea of the current register values. */
 243
 244 void
 245 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 246 {
 247   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 248   int regi;
 249
 250   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 251     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 252   regcache_raw_supply (regcache, PS_REGNUM, &regp[PT_SR]);
 253   regcache_raw_supply (regcache, PC_REGNUM, &regp[PT_PC]);
 254 }
 255
 256 /* Fill register REGNO (if it is a general-purpose register) in
 257    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 258    do this for all registers.  */
 259 void
 260 fill_gregset (const struct regcache *regcache,
 261               elf_gregset_t *gregsetp, int regno)
 262 {
 263   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 264   int i;
 265
 266   for (i = 0; i < NUM_GREGS; i++)
 267     if (regno == -1 || regno == i)
 268       regcache_raw_collect (regcache, i, regp + regmap[i]);
 269 }
 270
 271 #ifdef HAVE_PTRACE_GETREGS
 272
 273 /* Fetch all general-purpose registers from process/thread TID and
 274    store their values in GDB's register array.  */
 275
 276 static void
 277 fetch_regs (struct regcache *regcache, int tid)
 278 {
 279   elf_gregset_t regs;
 280
 281   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 282     {
 283       if (errno == EIO)
 284         {
 285           /* The kernel we're running on doesn't support the GETREGS
 286              request.  Reset `have_ptrace_getregs'.  */
 287           have_ptrace_getregs = 0;
 288           return;
 289         }
 290
 291       perror_with_name (_("Couldn't get registers"));
 292     }
 293
 294   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 295 }
 296
 297 /* Store all valid general-purpose registers in GDB's register array
 298    into the process/thread specified by TID.  */
 299
 300 static void
 301 store_regs (const struct regcache *regcache, int tid, int regno)
 302 {
 303   elf_gregset_t regs;
 304
 305   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 306     perror_with_name (_("Couldn't get registers"));
 307
 308   fill_gregset (regcache, &regs, regno);
 309
 310   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 311     perror_with_name (_("Couldn't write registers"));
 312 }
 313
 314 #else
 315
 316 static void fetch_regs (struct regcache *regcache, int tid) {}
 317 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 318
 319 #endif
 320
 321 \f
 322 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 323
 324 /* What is the address of fpN within the floating-point register set F?  */
 325 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 326
 327 /* Fill GDB's register array with the floating-point register values in
 328    *FPREGSETP.  */
 329
 330 void
 331 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 332 {
 333   int regi;
 334
 335   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 336     regcache_raw_supply (regcache, regi,
 337                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 338   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 339   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 340   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 341 }
 342
 343 /* Fill register REGNO (if it is a floating-point register) in
 344    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 345    do this for all registers.  */
 346
 347 void
 348 fill_fpregset (const struct regcache *regcache,
 349                elf_fpregset_t *fpregsetp, int regno)
 350 {
 351   int i;
 352
 353   /* Fill in the floating-point registers.  */
 354   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 355     if (regno == -1 || regno == i)
 356       regcache_raw_collect (regcache, i,
 357                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 358
 359   /* Fill in the floating-point control registers.  */
 360   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 361     if (regno == -1 || regno == i)
 362       regcache_raw_collect (regcache, i,
 363                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 364 }
 365
 366 #ifdef HAVE_PTRACE_GETREGS
 367
 368 /* Fetch all floating-point registers from process/thread TID and store
 369    thier values in GDB's register array.  */
 370
 371 static void
 372 fetch_fpregs (struct regcache *regcache, int tid)
 373 {
 374   elf_fpregset_t fpregs;
 375
 376   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 377     perror_with_name (_("Couldn't get floating point status"));
 378
 379   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 380 }
 381
 382 /* Store all valid floating-point registers in GDB's register array
 383    into the process/thread specified by TID.  */
 384
 385 static void
 386 store_fpregs (const struct regcache *regcache, int tid, int regno)
 387 {
 388   elf_fpregset_t fpregs;
 389
 390   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 391     perror_with_name (_("Couldn't get floating point status"));
 392
 393   fill_fpregset (regcache, &fpregs, regno);
 394
 395   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 396     perror_with_name (_("Couldn't write floating point status"));
 397 }
 398
 399 #else
 400
 401 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 402 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 403
 404 #endif
 405 \f
 406 /* Transferring arbitrary registers between GDB and inferior.  */
 407
 408 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 409    this for all registers (including the floating point and SSE
 410    registers).  */
 411
 412 static void
 413 m68k_linux_fetch_inferior_registers (struct regcache *regcache, int regno)
 414 {
 415   int tid;
 416
 417   /* Use the old method of peeking around in `struct user' if the
 418      GETREGS request isn't available.  */
 419   if (! have_ptrace_getregs)
 420     {
 421       old_fetch_inferior_registers (regcache, regno);
 422       return;
 423     }
 424
 425   /* GNU/Linux LWP ID's are process ID's.  */
 426   tid = TIDGET (inferior_ptid);
 427   if (tid == 0)
 428     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 429
 430   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 431      transfers more registers in one system call, and we'll cache the
 432      results.  But remember that fetch_fpxregs can fail, and return
 433      zero.  */
 434   if (regno == -1)
 435     {
 436       fetch_regs (regcache, tid);
 437
 438       /* The call above might reset `have_ptrace_getregs'.  */
 439       if (! have_ptrace_getregs)
 440         {
 441           old_fetch_inferior_registers (regcache, -1);
 442           return;
 443         }
 444
 445       fetch_fpregs (regcache, tid);
 446       return;
 447     }
 448
 449   if (getregs_supplies (regno))
 450     {
 451       fetch_regs (regcache, tid);
 452       return;
 453     }
 454
 455   if (getfpregs_supplies (regno))
 456     {
 457       fetch_fpregs (regcache, tid);
 458       return;
 459     }
 460
 461   internal_error (__FILE__, __LINE__,
 462                   _("Got request for bad register number %d."), regno);
 463 }
 464
 465 /* Store register REGNO back into the child process.  If REGNO is -1,
 466    do this for all registers (including the floating point and SSE
 467    registers).  */
 468 static void
 469 m68k_linux_store_inferior_registers (struct regcache *regcache, int regno)
 470 {
 471   int tid;
 472
 473   /* Use the old method of poking around in `struct user' if the
 474      SETREGS request isn't available.  */
 475   if (! have_ptrace_getregs)
 476     {
 477       old_store_inferior_registers (regcache, regno);
 478       return;
 479     }
 480
 481   /* GNU/Linux LWP ID's are process ID's.  */
 482   tid = TIDGET (inferior_ptid);
 483   if (tid == 0)
 484     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 485
 486   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 487      transfers more registers in one system call.  But remember that
 488      store_fpregs can fail, and return zero.  */
 489   if (regno == -1)
 490     {
 491       store_regs (regcache, tid, regno);
 492       store_fpregs (regcache, tid, regno);
 493       return;
 494     }
 495
 496   if (getregs_supplies (regno))
 497     {
 498       store_regs (regcache, tid, regno);
 499       return;
 500     }
 501
 502   if (getfpregs_supplies (regno))
 503     {
 504       store_fpregs (regcache, tid, regno);
 505       return;
 506     }
 507
 508   internal_error (__FILE__, __LINE__,
 509                   _("Got request to store bad register number %d."), regno);
 510 }
 511 \f
 512 /* Interpreting register set info found in core files.  */
 513
 514 /* Provide registers to GDB from a core file.
 515
 516    (We can't use the generic version of this function in
 517    core-regset.c, because we need to use elf_gregset_t instead of
 518    gregset_t.)
 519
 520    CORE_REG_SECT points to an array of bytes, which are the contents
 521    of a `note' from a core file which BFD thinks might contain
 522    register contents.  CORE_REG_SIZE is its size.
 523
 524    WHICH says which register set corelow suspects this is:
 525      0 --- the general-purpose register set, in elf_gregset_t format
 526      2 --- the floating-point register set, in elf_fpregset_t format
 527
 528    REG_ADDR isn't used on GNU/Linux.  */
 529
 530 static void
 531 fetch_core_registers (struct regcache *regcache,
 532                       char *core_reg_sect, unsigned core_reg_size,
 533                       int which, CORE_ADDR reg_addr)
 534 {
 535   elf_gregset_t gregset;
 536   elf_fpregset_t fpregset;
 537
 538   switch (which)
 539     {
 540     case 0:
 541       if (core_reg_size != sizeof (gregset))
 542         warning (_("Wrong size gregset in core file."));
 543       else
 544         {
 545           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 546           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 547         }
 548       break;
 549
 550     case 2:
 551       if (core_reg_size != sizeof (fpregset))
 552         warning (_("Wrong size fpregset in core file."));
 553       else
 554         {
 555           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 556           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 557         }
 558       break;
 559
 560     default:
 561       /* We've covered all the kinds of registers we know about here,
 562          so this must be something we wouldn't know what to do with
 563          anyway.  Just ignore it.  */
 564       break;
 565     }
 566 }
 567 \f
 568
 569 /* Register that we are able to handle GNU/Linux ELF core file
 570    formats.  */
 571
 572 static struct core_fns linux_elf_core_fns =
 573 {
 574   bfd_target_elf_flavour,               /* core_flavour */
 575   default_check_format,                 /* check_format */
 576   default_core_sniffer,                 /* core_sniffer */
 577   fetch_core_registers,                 /* core_read_registers */
 578   NULL                                  /* next */
 579 };
 580
 581 void _initialize_m68k_linux_nat (void);
 582
 583 void
 584 _initialize_m68k_linux_nat (void)
 585 {
 586   struct target_ops *t;
 587
 588   /* Fill in the generic GNU/Linux methods.  */
 589   t = linux_target ();
 590
 591   /* Add our register access methods.  */
 592   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 593   t->to_store_registers = m68k_linux_store_inferior_registers;
 594
 595   /* Register the target.  */
 596   linux_nat_add_target (t);
 597
 598   deprecated_add_core_fns (&linux_elf_core_fns);
 599 }