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 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 gdbarch_fp0_regnum (current_gdbarch) <= regno
  83          && regno <= M68K_FPI_REGNUM;
  84 }
  85
  86 /* Does the current host support the GETREGS request?  */
  87 int have_ptrace_getregs =
  88 #ifdef HAVE_PTRACE_GETREGS
  89   1
  90 #else
  91   0
  92 #endif
  93 ;
  94
  95 \f
  96
  97 /* Fetching registers directly from the U area, one at a time.  */
  98
  99 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 100    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 101    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 102    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 103    fall back on that code when GDB is running on top of a kernel that
 104    doesn't support the GETREGS request.  */
 105
 106 #ifndef PT_READ_U
 107 #define PT_READ_U PTRACE_PEEKUSR
 108 #endif
 109 #ifndef PT_WRITE_U
 110 #define PT_WRITE_U PTRACE_POKEUSR
 111 #endif
 112
 113 /* Fetch one register.  */
 114
 115 static void
 116 fetch_register (struct regcache *regcache, int regno)
 117 {
 118   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 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 (gdbarch_cannot_fetch_register (gdbarch, regno))
 127     {
 128       memset (buf, '\0', register_size (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 (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                    gdbarch_register_name (gdbarch, 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;
 170            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 171            regno++)
 172         {
 173           fetch_register (regcache, regno);
 174         }
 175     }
 176 }
 177
 178 /* Store one register. */
 179
 180 static void
 181 store_register (const struct regcache *regcache, int regno)
 182 {
 183   struct gdbarch *gdbarch = reg_regcache_arch (regcache);
 184   /* This isn't really an address.  But ptrace thinks of it as one.  */
 185   CORE_ADDR regaddr;
 186   char mess[128];               /* For messages */
 187   int i;
 188   int tid;
 189   char buf[MAX_REGISTER_SIZE];
 190
 191   if (gdbarch_cannot_store_register (gdbarch, regno))
 192     return;
 193
 194   /* Overload thread id onto process id */
 195   tid = TIDGET (inferior_ptid);
 196   if (tid == 0)
 197     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 198
 199   regaddr = 4 * regmap[regno];
 200
 201   /* Put the contents of regno into a local buffer */
 202   regcache_raw_collect (regcache, regno, buf);
 203
 204   /* Store the local buffer into the inferior a chunk at the time. */
 205   for (i = 0; i < register_size (gdbarch, regno);
 206        i += sizeof (PTRACE_TYPE_RET))
 207     {
 208       errno = 0;
 209       ptrace (PT_WRITE_U, tid, (PTRACE_TYPE_ARG3) regaddr,
 210               *(PTRACE_TYPE_RET *) (buf + i));
 211       regaddr += sizeof (PTRACE_TYPE_RET);
 212       if (errno != 0)
 213         {
 214           sprintf (mess, "writing register %s (#%d)",
 215                    gdbarch_register_name (gdbarch, regno), regno);
 216           perror_with_name (mess);
 217         }
 218     }
 219 }
 220
 221 /* Store our register values back into the inferior.
 222    If REGNO is negative, do this for all registers.
 223    Otherwise, REGNO specifies which register (so we can save time).  */
 224
 225 static void
 226 old_store_inferior_registers (const struct regcache *regcache, int regno)
 227 {
 228   if (regno >= 0)
 229     {
 230       store_register (regcache, regno);
 231     }
 232   else
 233     {
 234       for (regno = 0;
 235            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 236            regno++)
 237         {
 238           store_register (regcache, regno);
 239         }
 240     }
 241 }
 242 \f
 243 /*  Given a pointer to a general register set in /proc format
 244    (elf_gregset_t *), unpack the register contents and supply
 245    them as gdb's idea of the current register values. */
 246
 247 void
 248 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 249 {
 250   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 251   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 252   int regi;
 253
 254   for (regi = M68K_D0_REGNUM;
 255        regi <= gdbarch_sp_regnum (gdbarch);
 256        regi++)
 257     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 258   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 259                        &regp[PT_SR]);
 260   regcache_raw_supply (regcache,
 261                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 262 }
 263
 264 /* Fill register REGNO (if it is a general-purpose register) in
 265    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 266    do this for all registers.  */
 267 void
 268 fill_gregset (const struct regcache *regcache,
 269               elf_gregset_t *gregsetp, int regno)
 270 {
 271   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 272   int i;
 273
 274   for (i = 0; i < NUM_GREGS; i++)
 275     if (regno == -1 || regno == i)
 276       regcache_raw_collect (regcache, i, regp + regmap[i]);
 277 }
 278
 279 #ifdef HAVE_PTRACE_GETREGS
 280
 281 /* Fetch all general-purpose registers from process/thread TID and
 282    store their values in GDB's register array.  */
 283
 284 static void
 285 fetch_regs (struct regcache *regcache, int tid)
 286 {
 287   elf_gregset_t regs;
 288
 289   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 290     {
 291       if (errno == EIO)
 292         {
 293           /* The kernel we're running on doesn't support the GETREGS
 294              request.  Reset `have_ptrace_getregs'.  */
 295           have_ptrace_getregs = 0;
 296           return;
 297         }
 298
 299       perror_with_name (_("Couldn't get registers"));
 300     }
 301
 302   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 303 }
 304
 305 /* Store all valid general-purpose registers in GDB's register array
 306    into the process/thread specified by TID.  */
 307
 308 static void
 309 store_regs (const struct regcache *regcache, int tid, int regno)
 310 {
 311   elf_gregset_t regs;
 312
 313   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 314     perror_with_name (_("Couldn't get registers"));
 315
 316   fill_gregset (regcache, &regs, regno);
 317
 318   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 319     perror_with_name (_("Couldn't write registers"));
 320 }
 321
 322 #else
 323
 324 static void fetch_regs (struct regcache *regcache, int tid) {}
 325 static void store_regs (const struct regcache *regcache, int tid, int regno) {}
 326
 327 #endif
 328
 329 \f
 330 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 331
 332 /* What is the address of fpN within the floating-point register set F?  */
 333 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 334
 335 /* Fill GDB's register array with the floating-point register values in
 336    *FPREGSETP.  */
 337
 338 void
 339 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 340 {
 341   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 342   int regi;
 343
 344   for (regi = gdbarch_fp0_regnum (gdbarch);
 345        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 346     regcache_raw_supply (regcache, regi,
 347                          FPREG_ADDR (fpregsetp,
 348                                      regi - gdbarch_fp0_regnum (gdbarch)));
 349   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 350   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 351   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 352 }
 353
 354 /* Fill register REGNO (if it is a floating-point register) in
 355    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 356    do this for all registers.  */
 357
 358 void
 359 fill_fpregset (const struct regcache *regcache,
 360                elf_fpregset_t *fpregsetp, int regno)
 361 {
 362   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 363   int i;
 364
 365   /* Fill in the floating-point registers.  */
 366   for (i = gdbarch_fp0_regnum (gdbarch);
 367        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 368     if (regno == -1 || regno == i)
 369       regcache_raw_collect (regcache, i,
 370                             FPREG_ADDR (fpregsetp,
 371                                         i - gdbarch_fp0_regnum (gdbarch)));
 372
 373   /* Fill in the floating-point control registers.  */
 374   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 375     if (regno == -1 || regno == i)
 376       regcache_raw_collect (regcache, i,
 377                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 378 }
 379
 380 #ifdef HAVE_PTRACE_GETREGS
 381
 382 /* Fetch all floating-point registers from process/thread TID and store
 383    thier values in GDB's register array.  */
 384
 385 static void
 386 fetch_fpregs (struct regcache *regcache, int tid)
 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   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 394 }
 395
 396 /* Store all valid floating-point registers in GDB's register array
 397    into the process/thread specified by TID.  */
 398
 399 static void
 400 store_fpregs (const struct regcache *regcache, int tid, int regno)
 401 {
 402   elf_fpregset_t fpregs;
 403
 404   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 405     perror_with_name (_("Couldn't get floating point status"));
 406
 407   fill_fpregset (regcache, &fpregs, regno);
 408
 409   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 410     perror_with_name (_("Couldn't write floating point status"));
 411 }
 412
 413 #else
 414
 415 static void fetch_fpregs (struct regcache *regcache, int tid) {}
 416 static void store_fpregs (const struct regcache *regcache, int tid, int regno) {}
 417
 418 #endif
 419 \f
 420 /* Transferring arbitrary registers between GDB and inferior.  */
 421
 422 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 423    this for all registers (including the floating point and SSE
 424    registers).  */
 425
 426 static void
 427 m68k_linux_fetch_inferior_registers (struct regcache *regcache, int regno)
 428 {
 429   int tid;
 430
 431   /* Use the old method of peeking around in `struct user' if the
 432      GETREGS request isn't available.  */
 433   if (! have_ptrace_getregs)
 434     {
 435       old_fetch_inferior_registers (regcache, regno);
 436       return;
 437     }
 438
 439   /* GNU/Linux LWP ID's are process ID's.  */
 440   tid = TIDGET (inferior_ptid);
 441   if (tid == 0)
 442     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 443
 444   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 445      transfers more registers in one system call, and we'll cache the
 446      results.  But remember that fetch_fpxregs can fail, and return
 447      zero.  */
 448   if (regno == -1)
 449     {
 450       fetch_regs (regcache, tid);
 451
 452       /* The call above might reset `have_ptrace_getregs'.  */
 453       if (! have_ptrace_getregs)
 454         {
 455           old_fetch_inferior_registers (regcache, -1);
 456           return;
 457         }
 458
 459       fetch_fpregs (regcache, tid);
 460       return;
 461     }
 462
 463   if (getregs_supplies (regno))
 464     {
 465       fetch_regs (regcache, tid);
 466       return;
 467     }
 468
 469   if (getfpregs_supplies (regno))
 470     {
 471       fetch_fpregs (regcache, tid);
 472       return;
 473     }
 474
 475   internal_error (__FILE__, __LINE__,
 476                   _("Got request for bad register number %d."), regno);
 477 }
 478
 479 /* Store register REGNO back into the child process.  If REGNO is -1,
 480    do this for all registers (including the floating point and SSE
 481    registers).  */
 482 static void
 483 m68k_linux_store_inferior_registers (struct regcache *regcache, int regno)
 484 {
 485   int tid;
 486
 487   /* Use the old method of poking around in `struct user' if the
 488      SETREGS request isn't available.  */
 489   if (! have_ptrace_getregs)
 490     {
 491       old_store_inferior_registers (regcache, regno);
 492       return;
 493     }
 494
 495   /* GNU/Linux LWP ID's are process ID's.  */
 496   tid = TIDGET (inferior_ptid);
 497   if (tid == 0)
 498     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 499
 500   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 501      transfers more registers in one system call.  But remember that
 502      store_fpregs can fail, and return zero.  */
 503   if (regno == -1)
 504     {
 505       store_regs (regcache, tid, regno);
 506       store_fpregs (regcache, tid, regno);
 507       return;
 508     }
 509
 510   if (getregs_supplies (regno))
 511     {
 512       store_regs (regcache, tid, regno);
 513       return;
 514     }
 515
 516   if (getfpregs_supplies (regno))
 517     {
 518       store_fpregs (regcache, tid, regno);
 519       return;
 520     }
 521
 522   internal_error (__FILE__, __LINE__,
 523                   _("Got request to store bad register number %d."), regno);
 524 }
 525 \f
 526 /* Interpreting register set info found in core files.  */
 527
 528 /* Provide registers to GDB from a core file.
 529
 530    (We can't use the generic version of this function in
 531    core-regset.c, because we need to use elf_gregset_t instead of
 532    gregset_t.)
 533
 534    CORE_REG_SECT points to an array of bytes, which are the contents
 535    of a `note' from a core file which BFD thinks might contain
 536    register contents.  CORE_REG_SIZE is its size.
 537
 538    WHICH says which register set corelow suspects this is:
 539      0 --- the general-purpose register set, in elf_gregset_t format
 540      2 --- the floating-point register set, in elf_fpregset_t format
 541
 542    REG_ADDR isn't used on GNU/Linux.  */
 543
 544 static void
 545 fetch_core_registers (struct regcache *regcache,
 546                       char *core_reg_sect, unsigned core_reg_size,
 547                       int which, CORE_ADDR reg_addr)
 548 {
 549   elf_gregset_t gregset;
 550   elf_fpregset_t fpregset;
 551
 552   switch (which)
 553     {
 554     case 0:
 555       if (core_reg_size != sizeof (gregset))
 556         warning (_("Wrong size gregset in core file."));
 557       else
 558         {
 559           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 560           supply_gregset (regcache, (const elf_gregset_t *) &gregset);
 561         }
 562       break;
 563
 564     case 2:
 565       if (core_reg_size != sizeof (fpregset))
 566         warning (_("Wrong size fpregset in core file."));
 567       else
 568         {
 569           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 570           supply_fpregset (regcache, (const elf_fpregset_t *) &fpregset);
 571         }
 572       break;
 573
 574     default:
 575       /* We've covered all the kinds of registers we know about here,
 576          so this must be something we wouldn't know what to do with
 577          anyway.  Just ignore it.  */
 578       break;
 579     }
 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 }