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 #ifdef USG
  34 #include <sys/types.h>
  35 #endif
  36
  37 #include <sys/param.h>
  38 #include <sys/dir.h>
  39 #include <signal.h>
  40 #include <sys/ptrace.h>
  41 #include <sys/user.h>
  42 #include <sys/ioctl.h>
  43 #include <fcntl.h>
  44 #include <sys/procfs.h>
  45
  46 #ifdef HAVE_SYS_REG_H
  47 #include <sys/reg.h>
  48 #endif
  49
  50 #include <sys/file.h>
  51 #include "gdb_stat.h"
  52
  53 #include "floatformat.h"
  54
  55 #include "target.h"
  56 \f
  57 /* This table must line up with REGISTER_NAMES in tm-m68k.h */
  58 static const int regmap[] =
  59 {
  60   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  61   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  62   PT_SR, PT_PC,
  63   /* PT_FP0, ..., PT_FP7 */
  64   21, 24, 27, 30, 33, 36, 39, 42,
  65   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  66   45, 46, 47
  67 };
  68
  69 /* Which ptrace request retrieves which registers?
  70    These apply to the corresponding SET requests as well.  */
  71 #define NUM_GREGS (18)
  72 #define MAX_NUM_REGS (NUM_GREGS + 11)
  73
  74 int
  75 getregs_supplies (int regno)
  76 {
  77   return 0 <= regno && regno < NUM_GREGS;
  78 }
  79
  80 int
  81 getfpregs_supplies (int regno)
  82 {
  83   return FP0_REGNUM <= regno && 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 /* BLOCKEND is the value of u.u_ar0, and points to the place where GS
  98    is stored.  */
  99
 100 int
 101 m68k_linux_register_u_addr (int blockend, int regnum)
 102 {
 103   return (blockend + 4 * regmap[regnum]);
 104 }
 105 \f
 106
 107 /* Fetching registers directly from the U area, one at a time.  */
 108
 109 /* FIXME: This duplicates code from `inptrace.c'.  The problem is that we
 110    define FETCH_INFERIOR_REGISTERS since we want to use our own versions
 111    of {fetch,store}_inferior_registers that use the GETREGS request.  This
 112    means that the code in `infptrace.c' is #ifdef'd out.  But we need to
 113    fall back on that code when GDB is running on top of a kernel that
 114    doesn't support the GETREGS request.  */
 115
 116 #ifndef PT_READ_U
 117 #define PT_READ_U PTRACE_PEEKUSR
 118 #endif
 119 #ifndef PT_WRITE_U
 120 #define PT_WRITE_U PTRACE_POKEUSR
 121 #endif
 122
 123 /* Default the type of the ptrace transfer to int.  */
 124 #ifndef PTRACE_XFER_TYPE
 125 #define PTRACE_XFER_TYPE int
 126 #endif
 127
 128 /* Fetch one register.  */
 129
 130 static void
 131 fetch_register (int regno)
 132 {
 133   /* This isn't really an address.  But ptrace thinks of it as one.  */
 134   CORE_ADDR regaddr;
 135   char mess[128];               /* For messages */
 136   register int i;
 137   unsigned int offset;          /* Offset of registers within the u area.  */
 138   char buf[MAX_REGISTER_SIZE];
 139   int tid;
 140
 141   if (CANNOT_FETCH_REGISTER (regno))
 142     {
 143       memset (buf, '\0', REGISTER_RAW_SIZE (regno));    /* Supply zeroes */
 144       supply_register (regno, buf);
 145       return;
 146     }
 147
 148   /* Overload thread id onto process id */
 149   if ((tid = TIDGET (inferior_ptid)) == 0)
 150     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 151
 152   offset = U_REGS_OFFSET;
 153
 154   regaddr = register_addr (regno, offset);
 155   for (i = 0; i < REGISTER_RAW_SIZE (regno); 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   supply_register (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 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   register 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   if ((tid = TIDGET (inferior_ptid)) == 0)
 211     tid = PIDGET (inferior_ptid);       /* no thread id, just use process id */
 212
 213   offset = U_REGS_OFFSET;
 214
 215   regaddr = register_addr (regno, offset);
 216
 217   /* Put the contents of regno into a local buffer */
 218   regcache_collect (regno, buf);
 219
 220   /* Store the local buffer into the inferior a chunk at the time. */
 221   for (i = 0; i < REGISTER_RAW_SIZE (regno); 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     supply_register (regi, (char *) &regp[regmap[regi]]);
 282   supply_register (PS_REGNUM, (char *) &regp[PT_SR]);
 283   supply_register (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_collect (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     supply_register (regi, FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 366   supply_register (M68K_FPC_REGNUM, (char *) &fpregsetp->fpcntl[0]);
 367   supply_register (M68K_FPS_REGNUM, (char *) &fpregsetp->fpcntl[1]);
 368   supply_register (M68K_FPI_REGNUM, (char *) &fpregsetp->fpcntl[2]);
 369 }
 370
 371 /* Fill register REGNO (if it is a floating-point register) in
 372    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 373    do this for all registers.  */
 374
 375 void
 376 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 377 {
 378   int i;
 379
 380   /* Fill in the floating-point registers.  */
 381   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 382     if (regno == -1 || regno == i)
 383       regcache_collect (regno, FPREG_ADDR (fpregsetp, regno - FP0_REGNUM));
 384
 385   /* Fill in the floating-point control registers.  */
 386   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 387     if (regno == -1 || regno == i)
 388       regcache_collect (regno, (char *) &fpregsetp->fpcntl[regno - M68K_FPC_REGNUM]);
 389 }
 390
 391 #ifdef HAVE_PTRACE_GETREGS
 392
 393 /* Fetch all floating-point registers from process/thread TID and store
 394    thier values in GDB's register array.  */
 395
 396 static void
 397 fetch_fpregs (int tid)
 398 {
 399   elf_fpregset_t fpregs;
 400
 401   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 402     perror_with_name ("Couldn't get floating point status");
 403
 404   supply_fpregset (&fpregs);
 405 }
 406
 407 /* Store all valid floating-point registers in GDB's register array
 408    into the process/thread specified by TID.  */
 409
 410 static void
 411 store_fpregs (int tid, int regno)
 412 {
 413   elf_fpregset_t fpregs;
 414
 415   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 416     perror_with_name ("Couldn't get floating point status");
 417
 418   fill_fpregset (&fpregs, regno);
 419
 420   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 421     perror_with_name ("Couldn't write floating point status");
 422 }
 423
 424 #else
 425
 426 static void fetch_fpregs (int tid) {}
 427 static void store_fpregs (int tid, int regno) {}
 428
 429 #endif
 430
 431 #endif
 432 \f
 433 /* Transferring arbitrary registers between GDB and inferior.  */
 434
 435 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 436    this for all registers (including the floating point and SSE
 437    registers).  */
 438
 439 void
 440 fetch_inferior_registers (int regno)
 441 {
 442   int tid;
 443
 444   /* Use the old method of peeking around in `struct user' if the
 445      GETREGS request isn't available.  */
 446   if (! have_ptrace_getregs)
 447     {
 448       old_fetch_inferior_registers (regno);
 449       return;
 450     }
 451
 452   /* GNU/Linux LWP ID's are process ID's.  */
 453   if ((tid = TIDGET (inferior_ptid)) == 0)
 454     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 455
 456   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 457      transfers more registers in one system call, and we'll cache the
 458      results.  But remember that fetch_fpxregs can fail, and return
 459      zero.  */
 460   if (regno == -1)
 461     {
 462       fetch_regs (tid);
 463
 464       /* The call above might reset `have_ptrace_getregs'.  */
 465       if (! have_ptrace_getregs)
 466         {
 467           old_fetch_inferior_registers (-1);
 468           return;
 469         }
 470
 471       fetch_fpregs (tid);
 472       return;
 473     }
 474
 475   if (getregs_supplies (regno))
 476     {
 477       fetch_regs (tid);
 478       return;
 479     }
 480
 481   if (getfpregs_supplies (regno))
 482     {
 483       fetch_fpregs (tid);
 484       return;
 485     }
 486
 487   internal_error (__FILE__, __LINE__,
 488                   "Got request for bad register number %d.", regno);
 489 }
 490
 491 /* Store register REGNO back into the child process.  If REGNO is -1,
 492    do this for all registers (including the floating point and SSE
 493    registers).  */
 494 void
 495 store_inferior_registers (int regno)
 496 {
 497   int tid;
 498
 499   /* Use the old method of poking around in `struct user' if the
 500      SETREGS request isn't available.  */
 501   if (! have_ptrace_getregs)
 502     {
 503       old_store_inferior_registers (regno);
 504       return;
 505     }
 506
 507   /* GNU/Linux LWP ID's are process ID's.  */
 508   if ((tid = TIDGET (inferior_ptid)) == 0)
 509     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 510
 511   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 512      transfers more registers in one system call.  But remember that
 513      store_fpregs can fail, and return zero.  */
 514   if (regno == -1)
 515     {
 516       store_regs (tid, regno);
 517       store_fpregs (tid, regno);
 518       return;
 519     }
 520
 521   if (getregs_supplies (regno))
 522     {
 523       store_regs (tid, regno);
 524       return;
 525     }
 526
 527   if (getfpregs_supplies (regno))
 528     {
 529       store_fpregs (tid, regno);
 530       return;
 531     }
 532
 533   internal_error (__FILE__, __LINE__,
 534                   "Got request to store bad register number %d.", regno);
 535 }
 536 \f
 537 /* Interpreting register set info found in core files.  */
 538
 539 /* Provide registers to GDB from a core file.
 540
 541    (We can't use the generic version of this function in
 542    core-regset.c, because we need to use elf_gregset_t instead of
 543    gregset_t.)
 544
 545    CORE_REG_SECT points to an array of bytes, which are the contents
 546    of a `note' from a core file which BFD thinks might contain
 547    register contents.  CORE_REG_SIZE is its size.
 548
 549    WHICH says which register set corelow suspects this is:
 550      0 --- the general-purpose register set, in elf_gregset_t format
 551      2 --- the floating-point register set, in elf_fpregset_t format
 552
 553    REG_ADDR isn't used on GNU/Linux.  */
 554
 555 static void
 556 fetch_core_registers (char *core_reg_sect, unsigned core_reg_size,
 557                       int which, CORE_ADDR reg_addr)
 558 {
 559   elf_gregset_t gregset;
 560   elf_fpregset_t fpregset;
 561
 562   switch (which)
 563     {
 564     case 0:
 565       if (core_reg_size != sizeof (gregset))
 566         warning ("Wrong size gregset in core file.");
 567       else
 568         {
 569           memcpy (&gregset, core_reg_sect, sizeof (gregset));
 570           supply_gregset (&gregset);
 571         }
 572       break;
 573
 574     case 2:
 575       if (core_reg_size != sizeof (fpregset))
 576         warning ("Wrong size fpregset in core file.");
 577       else
 578         {
 579           memcpy (&fpregset, core_reg_sect, sizeof (fpregset));
 580           supply_fpregset (&fpregset);
 581         }
 582       break;
 583
 584     default:
 585       /* We've covered all the kinds of registers we know about here,
 586          so this must be something we wouldn't know what to do with
 587          anyway.  Just ignore it.  */
 588       break;
 589     }
 590 }
 591 \f
 592
 593 int
 594 kernel_u_size (void)
 595 {
 596   return (sizeof (struct user));
 597 }
 598 \f
 599 /* Register that we are able to handle GNU/Linux ELF core file
 600    formats.  */
 601
 602 static struct core_fns linux_elf_core_fns =
 603 {
 604   bfd_target_elf_flavour,               /* core_flavour */
 605   default_check_format,                 /* check_format */
 606   default_core_sniffer,                 /* core_sniffer */
 607   fetch_core_registers,                 /* core_read_registers */
 608   NULL                                  /* next */
 609 };
 610
 611 void
 612 _initialize_m68k_linux_nat (void)
 613 {
 614   add_core_fns (&linux_elf_core_fns);
 615 }