gdb/m68klinux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright 1996, 1998, 2000, 2001, 2002 Free Software Foundation,
   4    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., 59 Temple Place - Suite 330,
  21    Boston, MA 02111-1307, 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
  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 \f
  53 /* This table must line up with REGISTER_NAME in "m68k-tdep.c".  */
  54 static const int regmap[] =
  55 {
  56   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  57   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  58   PT_SR, PT_PC,
  59   /* PT_FP0, ..., PT_FP7 */
  60   21, 24, 27, 30, 33, 36, 39, 42,
  61   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  62   45, 46, 47
  63 };
  64
  65 /* Which ptrace request retrieves which registers?
  66    These apply to the corresponding SET requests as well.  */
  67 #define NUM_GREGS (18)
  68 #define MAX_NUM_REGS (NUM_GREGS + 11)
  69
  70 int
  71 getregs_supplies (int regno)
  72 {
  73   return 0 <= regno && regno < NUM_GREGS;
  74 }
  75
  76 int
  77 getfpregs_supplies (int regno)
  78 {
  79   return FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  80 }
  81
  82 /* Does the current host support the GETREGS request?  */
  83 int have_ptrace_getregs =
  84 #ifdef HAVE_PTRACE_GETREGS
  85   1
  86 #else
  87   0
  88 #endif
  89 ;
  90
  91 \f
  92
  93 /* BLOCKEND is the value of u.u_ar0, and points to the place where GS
  94    is stored.  */
  95
  96 int
  97 m68k_linux_register_u_addr (int blockend, int regnum)
  98 {
  99   return (blockend + 4 * regmap[regnum]);
 100 }
 101 \f
 102
 103 /* Fetching registers directly from the U area, one at a time.  */
 104
 105 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 106    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 107    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 108    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 109    fall back on that code when GDB is running on top of a kernel that
 110    doesn't support the GETREGS request.  */
 111
 112 #ifndef PT_READ_U
 113 #define PT_READ_U PTRACE_PEEKUSR
 114 #endif
 115 #ifndef PT_WRITE_U
 116 #define PT_WRITE_U PTRACE_POKEUSR
 117 #endif
 118
 119 /* Default the type of the ptrace transfer to int.  */
 120 #ifndef PTRACE_XFER_TYPE
 121 #define PTRACE_XFER_TYPE int
 122 #endif
 123
 124 /* Fetch one register.  */
 125
 126 static void
 127 fetch_register (int regno)
 128 {
 129   /* This isn't really an address.  But ptrace thinks of it as one.  */
 130   CORE_ADDR regaddr;
 131   char mess[128];               /* For messages */
 132   int i;
 133   unsigned int offset;          /* Offset of registers within the u area.  */
 134   char buf[MAX_REGISTER_SIZE];
 135   int tid;
 136
 137   if (CANNOT_FETCH_REGISTER (regno))
 138     {
 139       memset (buf, '\0', register_size (current_gdbarch, regno));       /* Supply zeroes */
 140       regcache_raw_supply (current_regcache, regno, buf);
 141       return;
 142     }
 143
 144   /* Overload thread id onto process id */
 145   tid = TIDGET (inferior_ptid);
 146   if (tid == 0)
 147     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 148
 149   offset = U_REGS_OFFSET;
 150
 151   regaddr = register_addr (regno, offset);
 152   for (i = 0; i < register_size (current_gdbarch, regno);
 153        i += sizeof (PTRACE_XFER_TYPE))
 154     {
 155       errno = 0;
 156       *(PTRACE_XFER_TYPE *) &buf[i] = ptrace (PT_READ_U, tid,
 157                                               (PTRACE_ARG3_TYPE) regaddr, 0);
 158       regaddr += sizeof (PTRACE_XFER_TYPE);
 159       if (errno != 0)
 160         {
 161           sprintf (mess, "reading register %s (#%d)",
 162                    REGISTER_NAME (regno), regno);
 163           perror_with_name (mess);
 164         }
 165     }
 166   regcache_raw_supply (current_regcache, regno, buf);
 167 }
 168
 169 /* Fetch register values from the inferior.
 170    If REGNO is negative, do this for all registers.
 171    Otherwise, REGNO specifies which register (so we can save time). */
 172
 173 void
 174 old_fetch_inferior_registers (int regno)
 175 {
 176   if (regno >= 0)
 177     {
 178       fetch_register (regno);
 179     }
 180   else
 181     {
 182       for (regno = 0; regno < NUM_REGS; regno++)
 183         {
 184           fetch_register (regno);
 185         }
 186     }
 187 }
 188
 189 /* Store one register. */
 190
 191 static void
 192 store_register (int regno)
 193 {
 194   /* This isn't really an address.  But ptrace thinks of it as one.  */
 195   CORE_ADDR regaddr;
 196   char mess[128];               /* For messages */
 197   int i;
 198   unsigned int offset;          /* Offset of registers within the u area.  */
 199   int tid;
 200   char buf[MAX_REGISTER_SIZE];
 201
 202   if (CANNOT_STORE_REGISTER (regno))
 203     {
 204       return;
 205     }
 206
 207   /* Overload thread id onto process id */
 208   tid = TIDGET (inferior_ptid);
 209   if (tid == 0)
 210     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 211
 212   offset = U_REGS_OFFSET;
 213
 214   regaddr = register_addr (regno, offset);
 215
 216   /* Put the contents of regno into a local buffer */
 217   regcache_raw_collect (current_regcache, regno, buf);
 218
 219   /* Store the local buffer into the inferior a chunk at the time. */
 220   for (i = 0; i < register_size (current_gdbarch, regno);
 221        i += sizeof (PTRACE_XFER_TYPE))
 222     {
 223       errno = 0;
 224       ptrace (PT_WRITE_U, tid, (PTRACE_ARG3_TYPE) regaddr,
 225               *(PTRACE_XFER_TYPE *) (buf + i));
 226       regaddr += sizeof (PTRACE_XFER_TYPE);
 227       if (errno != 0)
 228         {
 229           sprintf (mess, "writing register %s (#%d)",
 230                    REGISTER_NAME (regno), regno);
 231           perror_with_name (mess);
 232         }
 233     }
 234 }
 235
 236 /* Store our register values back into the inferior.
 237    If REGNO is negative, do this for all registers.
 238    Otherwise, REGNO specifies which register (so we can save time).  */
 239
 240 void
 241 old_store_inferior_registers (int regno)
 242 {
 243   if (regno >= 0)
 244     {
 245       store_register (regno);
 246     }
 247   else
 248     {
 249       for (regno = 0; regno < NUM_REGS; regno++)
 250         {
 251           store_register (regno);
 252         }
 253     }
 254 }
 255 \f
 256 /*  Given a pointer to a general register set in /proc format
 257    (elf_gregset_t *), unpack the register contents and supply
 258    them as gdb's idea of the current register values. */
 259
 260
 261 /* Note both m68k-tdep.c and m68klinux-nat.c contain definitions
 262    for supply_gregset and supply_fpregset. The definitions
 263    in m68k-tdep.c are valid if USE_PROC_FS is defined. Otherwise,
 264    the definitions in m68klinux-nat.c will be used. This is a
 265    bit of a hack. The supply_* routines do not belong in
 266    *_tdep.c files. But, there are several lynx ports that currently
 267    depend on these definitions. */
 268
 269 #ifndef USE_PROC_FS
 270
 271 /* Prototypes for supply_gregset etc. */
 272 #include "gregset.h"
 273
 274 void
 275 supply_gregset (elf_gregset_t *gregsetp)
 276 {
 277   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 278   int regi;
 279
 280   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 281     regcache_raw_supply (current_regcache, regi, (char *) &regp[regmap[regi]]);
 282   regcache_raw_supply (current_regcache, PS_REGNUM, (char *) &regp[PT_SR]);
 283   regcache_raw_supply (current_regcache, PC_REGNUM, (char *) &regp[PT_PC]);
 284 }
 285
 286 /* Fill register REGNO (if it is a general-purpose register) in
 287    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 288    do this for all registers.  */
 289 void
 290 fill_gregset (elf_gregset_t *gregsetp, int regno)
 291 {
 292   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 293   int i;
 294
 295   for (i = 0; i < NUM_GREGS; i++)
 296     if (regno == -1 || regno == i)
 297       regcache_raw_collect (current_regcache, i, regp + regmap[i]);
 298 }
 299
 300 #ifdef HAVE_PTRACE_GETREGS
 301
 302 /* Fetch all general-purpose registers from process/thread TID and
 303    store their values in GDB's register array.  */
 304
 305 static void
 306 fetch_regs (int tid)
 307 {
 308   elf_gregset_t regs;
 309
 310   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 311     {
 312       if (errno == EIO)
 313         {
 314           /* The kernel we're running on doesn't support the GETREGS
 315              request.  Reset `have_ptrace_getregs'.  */
 316           have_ptrace_getregs = 0;
 317           return;
 318         }
 319
 320       perror_with_name (_("Couldn't get registers"));
 321     }
 322
 323   supply_gregset (&regs);
 324 }
 325
 326 /* Store all valid general-purpose registers in GDB's register array
 327    into the process/thread specified by TID.  */
 328
 329 static void
 330 store_regs (int tid, int regno)
 331 {
 332   elf_gregset_t regs;
 333
 334   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 335     perror_with_name (_("Couldn't get registers"));
 336
 337   fill_gregset (&regs, regno);
 338
 339   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 340     perror_with_name (_("Couldn't write registers"));
 341 }
 342
 343 #else
 344
 345 static void fetch_regs (int tid) {}
 346 static void store_regs (int tid, int regno) {}
 347
 348 #endif
 349
 350 \f
 351 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 352
 353 /* What is the address of fpN within the floating-point register set F?  */
 354 #define FPREG_ADDR(f, n) ((char *) &(f)->fpregs[(n) * 3])
 355
 356 /* Fill GDB's register array with the floating-point register values in
 357    *FPREGSETP.  */
 358
 359 void
 360 supply_fpregset (elf_fpregset_t *fpregsetp)
 361 {
 362   int regi;
 363
 364   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 365     regcache_raw_supply (current_regcache, regi,
 366                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 367   regcache_raw_supply (current_regcache, M68K_FPC_REGNUM,
 368                        (char *) &fpregsetp->fpcntl[0]);
 369   regcache_raw_supply (current_regcache, M68K_FPS_REGNUM,
 370                        (char *) &fpregsetp->fpcntl[1]);
 371   regcache_raw_supply (current_regcache, M68K_FPI_REGNUM,
 372                        (char *) &fpregsetp->fpcntl[2]);
 373 }
 374
 375 /* Fill register REGNO (if it is a floating-point register) in
 376    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 377    do this for all registers.  */
 378
 379 void
 380 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 381 {
 382   int i;
 383
 384   /* Fill in the floating-point registers.  */
 385   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 386     if (regno == -1 || regno == i)
 387       regcache_raw_collect (current_regcache, i,
 388                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 389
 390   /* Fill in the floating-point control registers.  */
 391   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 392     if (regno == -1 || regno == i)
 393       regcache_raw_collect (current_regcache, i,
 394                             (char *) &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 395 }
 396
 397 #ifdef HAVE_PTRACE_GETREGS
 398
 399 /* Fetch all floating-point registers from process/thread TID and store
 400    thier values in GDB's register array.  */
 401
 402 static void
 403 fetch_fpregs (int tid)
 404 {
 405   elf_fpregset_t fpregs;
 406
 407   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 408     perror_with_name (_("Couldn't get floating point status"));
 409
 410   supply_fpregset (&fpregs);
 411 }
 412
 413 /* Store all valid floating-point registers in GDB's register array
 414    into the process/thread specified by TID.  */
 415
 416 static void
 417 store_fpregs (int tid, int regno)
 418 {
 419   elf_fpregset_t fpregs;
 420
 421   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 422     perror_with_name (_("Couldn't get floating point status"));
 423
 424   fill_fpregset (&fpregs, regno);
 425
 426   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 427     perror_with_name (_("Couldn't write floating point status"));
 428 }
 429
 430 #else
 431
 432 static void fetch_fpregs (int tid) {}
 433 static void store_fpregs (int tid, int regno) {}
 434
 435 #endif
 436
 437 #endif
 438 \f
 439 /* Transferring arbitrary registers between GDB and inferior.  */
 440
 441 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 442    this for all registers (including the floating point and SSE
 443    registers).  */
 444
 445 void
 446 fetch_inferior_registers (int regno)
 447 {
 448   int tid;
 449
 450   /* Use the old method of peeking around in `struct user' if the
 451      GETREGS request isn't available.  */
 452   if (! have_ptrace_getregs)
 453     {
 454       old_fetch_inferior_registers (regno);
 455       return;
 456     }
 457
 458   /* GNU/Linux LWP ID's are process ID's.  */
 459   tid = TIDGET (inferior_ptid);
 460   if (tid == 0)
 461     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 462
 463   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 464      transfers more registers in one system call, and we'll cache the
 465      results.  But remember that fetch_fpxregs can fail, and return
 466      zero.  */
 467   if (regno == -1)
 468     {
 469       fetch_regs (tid);
 470
 471       /* The call above might reset `have_ptrace_getregs'.  */
 472       if (! have_ptrace_getregs)
 473         {
 474           old_fetch_inferior_registers (-1);
 475           return;
 476         }
 477
 478       fetch_fpregs (tid);
 479       return;
 480     }
 481
 482   if (getregs_supplies (regno))
 483     {
 484       fetch_regs (tid);
 485       return;
 486     }
 487
 488   if (getfpregs_supplies (regno))
 489     {
 490       fetch_fpregs (tid);
 491       return;
 492     }
 493
 494   internal_error (__FILE__, __LINE__,
 495                   _("Got request for bad register number %d."), regno);
 496 }
 497
 498 /* Store register REGNO back into the child process.  If REGNO is -1,
 499    do this for all registers (including the floating point and SSE
 500    registers).  */
 501 void
 502 store_inferior_registers (int regno)
 503 {
 504   int tid;
 505
 506   /* Use the old method of poking around in `struct user' if the
 507      SETREGS request isn't available.  */
 508   if (! have_ptrace_getregs)
 509     {
 510       old_store_inferior_registers (regno);
 511       return;
 512     }
 513
 514   /* GNU/Linux LWP ID's are process ID's.  */
 515   tid = TIDGET (inferior_ptid);
 516   if (tid == 0)
 517     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 518
 519   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 520      transfers more registers in one system call.  But remember that
 521      store_fpregs can fail, and return zero.  */
 522   if (regno == -1)
 523     {
 524       store_regs (tid, regno);
 525       store_fpregs (tid, regno);
 526       return;
 527     }
 528
 529   if (getregs_supplies (regno))
 530     {
 531       store_regs (tid, regno);
 532       return;
 533     }
 534
 535   if (getfpregs_supplies (regno))
 536     {
 537       store_fpregs (tid, regno);
 538       return;
 539     }
 540
 541   internal_error (__FILE__, __LINE__,
 542                   _("Got request to store bad register number %d."), regno);
 543 }
 544 \f
 545 /* Interpreting register set info found in core files.  */
 546
 547 /* Provide registers to GDB from a core file.
 548
 549    (We can't use the generic version of this function in
 550    core-regset.c, because we need to use elf_gregset_t instead of
 551    gregset_t.)
 552
 553    CORE_REG_SECT points to an array of bytes, which are the contents
 554    of a `note' from a core file which BFD thinks might contain
 555    register contents.  CORE_REG_SIZE is its size.
 556
 557    WHICH says which register set corelow suspects this is:
 558      0 --- the general-purpose register set, in elf_gregset_t format
 559      2 --- the floating-point register set, in elf_fpregset_t format
 560
 561    REG_ADDR isn't used on GNU/Linux.  */
 562
 563 static void
 564 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size,
 565                       int which, CORE_ADDR reg_addr)
 566 {
 567   elf_gregset_t gregset;
 568   elf_fpregset_t fpregset;
 569
 570   switch (which)
 571     {
 572     case 0:
 573       if (core_reg_size != sizeof (gregset))
 574         warning (_("Wrong size gregset in core file."));
 575       else
 576         {
 577           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 578           supply_gregset (&gregset);
 579         }
 580       break;
 581
 582     case 2:
 583       if (core_reg_size != sizeof (fpregset))
 584         warning (_("Wrong size fpregset in core file."));
 585       else
 586         {
 587           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 588           supply_fpregset (&fpregset);
 589         }
 590       break;
 591
 592     default:
 593       /* We've covered all the kinds of registers we know about here,
 594          so this must be something we wouldn't know what to do with
 595          anyway.  Just ignore it.  */
 596       break;
 597     }
 598 }
 599 \f
 600
 601 int
 602 kernel_u_size (void)
 603 {
 604   return (sizeof (struct user));
 605 }
 606 \f
 607 /* Register that we are able to handle GNU/Linux ELF core file
 608    formats.  */
 609
 610 static struct core_fns linux_elf_core_fns =
 611 {
 612   bfd_target_elf_flavour,               /* core_flavour */
 613   default_check_format,                 /* check_format */
 614   default_core_sniffer,                 /* core_sniffer */
 615   fetch_core_registers,                 /* core_read_registers */
 616   NULL                                  /* next */
 617 };
 618
 619 void
 620 _initialize_m68k_linux_nat (void)
 621 {
 622   deprecated_add_core_fns (&linux_elf_core_fns);
 623 }