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 \f
  55 /* This table must line up with 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 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 /* BLOCKEND is the value of u.u_ar0, and points to the place where GS
  96    is stored.  */
  97
  98 int
  99 m68k_linux_register_u_addr (int blockend, int regnum)
 100 {
 101   return (blockend + 4 * regmap[regnum]);
 102 }
 103 \f
 104
 105 /* Fetching registers directly from the U area, one at a time.  */
 106
 107 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 108    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 109    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 110    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 111    fall back on that code when GDB is running on top of a kernel that
 112    doesn't support the GETREGS request.  */
 113
 114 #ifndef PT_READ_U
 115 #define PT_READ_U PTRACE_PEEKUSR
 116 #endif
 117 #ifndef PT_WRITE_U
 118 #define PT_WRITE_U PTRACE_POKEUSR
 119 #endif
 120
 121 /* Default the type of the ptrace transfer to int.  */
 122 #ifndef PTRACE_XFER_TYPE
 123 #define PTRACE_XFER_TYPE int
 124 #endif
 125
 126 /* Fetch one register.  */
 127
 128 static void
 129 fetch_register (int regno)
 130 {
 131   /* This isn't really an address.  But ptrace thinks of it as one.  */
 132   CORE_ADDR regaddr;
 133   char mess[128];               /* For messages */
 134   int i;
 135   unsigned int offset;          /* Offset of registers within the u area.  */
 136   char buf[MAX_REGISTER_SIZE];
 137   int tid;
 138
 139   if (CANNOT_FETCH_REGISTER (regno))
 140     {
 141       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 142       regcache_raw_supply (current_regcache, regno, buf);
 143       return;
 144     }
 145
 146   /* Overload thread id onto process id */
 147   tid = TIDGET (inferior_ptid);
 148   if (tid == 0)
 149     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 150
 151   offset = U_REGS_OFFSET;
 152
 153   regaddr = register_addr (regno, offset);
 154   for (i = 0; i < register_size (current_gdbarch, regno);
 155        i += sizeof (PTRACE_XFER_TYPE))
 156     {
 157       errno = 0;
 158       *(PTRACE_XFER_TYPE *) &buf[i] = ptrace (PT_READ_U, tid,
 159                                               (PTRACE_ARG3_TYPE) regaddr, 0);
 160       regaddr += sizeof (PTRACE_XFER_TYPE);
 161       if (errno != 0)
 162         {
 163           sprintf (mess, "reading register %s (#%d)",
 164                    REGISTER_NAME (regno), regno);
 165           perror_with_name (mess);
 166         }
 167     }
 168   regcache_raw_supply (current_regcache, regno, buf);
 169 }
 170
 171 /* Fetch register values from the inferior.
 172    If REGNO is negative, do this for all registers.
 173    Otherwise, REGNO specifies which register (so we can save time). */
 174
 175 static void
 176 old_fetch_inferior_registers (int regno)
 177 {
 178   if (regno >= 0)
 179     {
 180       fetch_register (regno);
 181     }
 182   else
 183     {
 184       for (regno = 0; regno < NUM_REGS; regno++)
 185         {
 186           fetch_register (regno);
 187         }
 188     }
 189 }
 190
 191 /* Store one register. */
 192
 193 static void
 194 store_register (int regno)
 195 {
 196   /* This isn't really an address.  But ptrace thinks of it as one.  */
 197   CORE_ADDR regaddr;
 198   char mess[128];               /* For messages */
 199   int i;
 200   unsigned int offset;          /* Offset of registers within the u area.  */
 201   int tid;
 202   char buf[MAX_REGISTER_SIZE];
 203
 204   if (CANNOT_STORE_REGISTER (regno))
 205     {
 206       return;
 207     }
 208
 209   /* Overload thread id onto process id */
 210   tid = TIDGET (inferior_ptid);
 211   if (tid == 0)
 212     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 213
 214   offset = U_REGS_OFFSET;
 215
 216   regaddr = register_addr (regno, offset);
 217
 218   /* Put the contents of regno into a local buffer */
 219   regcache_raw_collect (current_regcache, regno, buf);
 220
 221   /* Store the local buffer into the inferior a chunk at the time. */
 222   for (i = 0; i < register_size (current_gdbarch, regno);
 223        i += sizeof (PTRACE_XFER_TYPE))
 224     {
 225       errno = 0;
 226       ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
 227               *(PTRACE_XFER_TYPE *) (buf + i));
 228       regaddr += sizeof (PTRACE_XFER_TYPE);
 229       if (errno != 0)
 230         {
 231           sprintf (mess, "writing register %s (#%d)",
 232                    REGISTER_NAME (regno), regno);
 233           perror_with_name (mess);
 234         }
 235     }
 236 }
 237
 238 /* Store our register values back into the inferior.
 239    If REGNO is negative, do this for all registers.
 240    Otherwise, REGNO specifies which register (so we can save time).  */
 241
 242 static void
 243 old_store_inferior_registers (int regno)
 244 {
 245   if (regno >= 0)
 246     {
 247       store_register (regno);
 248     }
 249   else
 250     {
 251       for (regno = 0; regno < NUM_REGS; regno++)
 252         {
 253           store_register (regno);
 254         }
 255     }
 256 }
 257 \f
 258 /*  Given a pointer to a general register set in /proc format
 259    (elf_gregset_t *), unpack the register contents and supply
 260    them as gdb's idea of the current register values. */
 261
 262
 263 /* Note both m68k-tdep.c and m68klinux-nat.c contain definitions
 264    for supply_gregset and supply_fpregset. The definitions
 265    in m68k-tdep.c are valid if USE_PROC_FS is defined. Otherwise,
 266    the definitions in m68klinux-nat.c will be used. This is a
 267    bit of a hack. The supply_* routines do not belong in
 268    *_tdep.c files. But, there are several lynx ports that currently
 269    depend on these definitions. */
 270
 271 #ifndef USE_PROC_FS
 272
 273 /* Prototypes for supply_gregset etc. */
 274 #include "gregset.h"
 275
 276 void
 277 supply_gregset (elf_gregset_t *gregsetp)
 278 {
 279   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 280   int regi;
 281
 282   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 283     regcache_raw_supply (current_regcache, regi, (char *) &regp[regmap[regi]]);
 284   regcache_raw_supply (current_regcache, PS_REGNUM, (char *) &regp[PT_SR]);
 285   regcache_raw_supply (current_regcache, PC_REGNUM, (char *) &regp[PT_PC]);
 286 }
 287
 288 /* Fill register REGNO (if it is a general-purpose register) in
 289    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 290    do this for all registers.  */
 291 void
 292 fill_gregset (elf_gregset_t *gregsetp, int regno)
 293 {
 294   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 295   int i;
 296
 297   for (i = 0; i < NUM_GREGS; i++)
 298     if (regno == -1 || regno == i)
 299       regcache_raw_collect (current_regcache, i, regp + regmap[i]);
 300 }
 301
 302 #ifdef HAVE_PTRACE_GETREGS
 303
 304 /* Fetch all general-purpose registers from process/thread TID and
 305    store their values in GDB's register array.  */
 306
 307 static void
 308 fetch_regs (int tid)
 309 {
 310   elf_gregset_t regs;
 311
 312   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 313     {
 314       if (errno == EIO)
 315         {
 316           /* The kernel we're running on doesn't support the GETREGS
 317              request.  Reset `have_ptrace_getregs'.  */
 318           have_ptrace_getregs = 0;
 319           return;
 320         }
 321
 322       perror_with_name (_("Couldn't get registers"));
 323     }
 324
 325   supply_gregset (&regs);
 326 }
 327
 328 /* Store all valid general-purpose registers in GDB's register array
 329    into the process/thread specified by TID.  */
 330
 331 static void
 332 store_regs (int tid, int regno)
 333 {
 334   elf_gregset_t regs;
 335
 336   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 337     perror_with_name (_("Couldn't get registers"));
 338
 339   fill_gregset (&regs, regno);
 340
 341   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 342     perror_with_name (_("Couldn't write registers"));
 343 }
 344
 345 #else
 346
 347 static void fetch_regs (int tid) {}
 348 static void store_regs (int tid, int regno) {}
 349
 350 #endif
 351
 352 \f
 353 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 354
 355 /* What is the address of fpN within the floating-point register set F?  */
 356 #define FPREG_ADDR(f, n) ((char *) &(f)->fpregs[(n) * 3])
 357
 358 /* Fill GDB's register array with the floating-point register values in
 359    *FPREGSETP.  */
 360
 361 void
 362 supply_fpregset (elf_fpregset_t *fpregsetp)
 363 {
 364   int regi;
 365
 366   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 367     regcache_raw_supply (current_regcache, regi,
 368                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 369   regcache_raw_supply (current_regcache, M68K_FPC_REGNUM,
 370                        (char *) &fpregsetp->fpcntl[0]);
 371   regcache_raw_supply (current_regcache, M68K_FPS_REGNUM,
 372                        (char *) &fpregsetp->fpcntl[1]);
 373   regcache_raw_supply (current_regcache, M68K_FPI_REGNUM,
 374                        (char *) &fpregsetp->fpcntl[2]);
 375 }
 376
 377 /* Fill register REGNO (if it is a floating-point register) in
 378    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 379    do this for all registers.  */
 380
 381 void
 382 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 383 {
 384   int i;
 385
 386   /* Fill in the floating-point registers.  */
 387   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 388     if (regno == -1 || regno == i)
 389       regcache_raw_collect (current_regcache, i,
 390                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 391
 392   /* Fill in the floating-point control registers.  */
 393   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 394     if (regno == -1 || regno == i)
 395       regcache_raw_collect (current_regcache, i,
 396                             (char *) &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 397 }
 398
 399 #ifdef HAVE_PTRACE_GETREGS
 400
 401 /* Fetch all floating-point registers from process/thread TID and store
 402    thier values in GDB's register array.  */
 403
 404 static void
 405 fetch_fpregs (int tid)
 406 {
 407   elf_fpregset_t fpregs;
 408
 409   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 410     perror_with_name (_("Couldn't get floating point status"));
 411
 412   supply_fpregset (&fpregs);
 413 }
 414
 415 /* Store all valid floating-point registers in GDB's register array
 416    into the process/thread specified by TID.  */
 417
 418 static void
 419 store_fpregs (int tid, int regno)
 420 {
 421   elf_fpregset_t fpregs;
 422
 423   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 424     perror_with_name (_("Couldn't get floating point status"));
 425
 426   fill_fpregset (&fpregs, regno);
 427
 428   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 429     perror_with_name (_("Couldn't write floating point status"));
 430 }
 431
 432 #else
 433
 434 static void fetch_fpregs (int tid) {}
 435 static void store_fpregs (int tid, int regno) {}
 436
 437 #endif
 438
 439 #endif
 440 \f
 441 /* Transferring arbitrary registers between GDB and inferior.  */
 442
 443 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 444    this for all registers (including the floating point and SSE
 445    registers).  */
 446
 447 static void
 448 m68k_linux_fetch_inferior_registers (int regno)
 449 {
 450   int tid;
 451
 452   /* Use the old method of peeking around in `struct user' if the
 453      GETREGS request isn't available.  */
 454   if (! have_ptrace_getregs)
 455     {
 456       old_fetch_inferior_registers (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_GETFPXREGS request whenever possible, since it
 466      transfers more registers in one system call, and we'll cache the
 467      results.  But remember that fetch_fpxregs can fail, and return
 468      zero.  */
 469   if (regno == -1)
 470     {
 471       fetch_regs (tid);
 472
 473       /* The call above might reset `have_ptrace_getregs'.  */
 474       if (! have_ptrace_getregs)
 475         {
 476           old_fetch_inferior_registers (-1);
 477           return;
 478         }
 479
 480       fetch_fpregs (tid);
 481       return;
 482     }
 483
 484   if (getregs_supplies (regno))
 485     {
 486       fetch_regs (tid);
 487       return;
 488     }
 489
 490   if (getfpregs_supplies (regno))
 491     {
 492       fetch_fpregs (tid);
 493       return;
 494     }
 495
 496   internal_error (__FILE__, __LINE__,
 497                   _("Got request for bad register number %d."), regno);
 498 }
 499
 500 /* Store register REGNO back into the child process.  If REGNO is -1,
 501    do this for all registers (including the floating point and SSE
 502    registers).  */
 503 static void
 504 m68k_linux_store_inferior_registers (int regno)
 505 {
 506   int tid;
 507
 508   /* Use the old method of poking around in `struct user' if the
 509      SETREGS request isn't available.  */
 510   if (! have_ptrace_getregs)
 511     {
 512       old_store_inferior_registers (regno);
 513       return;
 514     }
 515
 516   /* GNU/Linux LWP ID's are process ID's.  */
 517   tid = TIDGET (inferior_ptid);
 518   if (tid == 0)
 519     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 520
 521   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 522      transfers more registers in one system call.  But remember that
 523      store_fpregs can fail, and return zero.  */
 524   if (regno == -1)
 525     {
 526       store_regs (tid, regno);
 527       store_fpregs (tid, regno);
 528       return;
 529     }
 530
 531   if (getregs_supplies (regno))
 532     {
 533       store_regs (tid, regno);
 534       return;
 535     }
 536
 537   if (getfpregs_supplies (regno))
 538     {
 539       store_fpregs (tid, regno);
 540       return;
 541     }
 542
 543   internal_error (__FILE__, __LINE__,
 544                   _("Got request to store bad register number %d."), regno);
 545 }
 546 \f
 547 /* Interpreting register set info found in core files.  */
 548
 549 /* Provide registers to GDB from a core file.
 550
 551    (We can't use the generic version of this function in
 552    core-regset.c, because we need to use elf_gregset_t instead of
 553    gregset_t.)
 554
 555    CORE_REG_SECT points to an array of bytes, which are the contents
 556    of a `note' from a core file which BFD thinks might contain
 557    register contents.  CORE_REG_SIZE is its size.
 558
 559    WHICH says which register set corelow suspects this is:
 560      0 --- the general-purpose register set, in elf_gregset_t format
 561      2 --- the floating-point register set, in elf_fpregset_t format
 562
 563    REG_ADDR isn't used on GNU/Linux.  */
 564
 565 static void
 566 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size,
 567                       int which, CORE_ADDR reg_addr)
 568 {
 569   elf_gregset_t gregset;
 570   elf_fpregset_t fpregset;
 571
 572   switch (which)
 573     {
 574     case 0:
 575       if (core_reg_size != sizeof (gregset))
 576         warning (_("Wrong size gregset in core file."));
 577       else
 578         {
 579           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 580           supply_gregset (&gregset);
 581         }
 582       break;
 583
 584     case 2:
 585       if (core_reg_size != sizeof (fpregset))
 586         warning (_("Wrong size fpregset in core file."));
 587       else
 588         {
 589           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 590           supply_fpregset (&fpregset);
 591         }
 592       break;
 593
 594     default:
 595       /* We've covered all the kinds of registers we know about here,
 596          so this must be something we wouldn't know what to do with
 597          anyway.  Just ignore it.  */
 598       break;
 599     }
 600 }
 601 \f
 602
 603 int
 604 kernel_u_size (void)
 605 {
 606   return (sizeof (struct user));
 607 }
 608 \f
 609 /* Register that we are able to handle GNU/Linux ELF core file
 610    formats.  */
 611
 612 static struct core_fns linux_elf_core_fns =
 613 {
 614   bfd_target_elf_flavour,               /* core_flavour */
 615   default_check_format,                 /* check_format */
 616   default_core_sniffer,                 /* core_sniffer */
 617   fetch_core_registers,                 /* core_read_registers */
 618   NULL                                  /* next */
 619 };
 620
 621 void _initialize_m68k_linux_nat (void);
 622
 623 void
 624 _initialize_m68k_linux_nat (void)
 625 {
 626   struct target_ops *t;
 627
 628   /* Fill in the generic GNU/Linux methods.  */
 629   t = linux_target ();
 630
 631   /* Add our register access methods.  */
 632   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 633   t->to_store_registers = m68k_linux_store_inferior_registers;
 634
 635   /* Register the target.  */
 636   linux_nat_add_target (t);
 637
 638   deprecated_add_core_fns (&linux_elf_core_fns);
 639 }