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 (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 (current_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 (current_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 (int regno)
 162 {
 163   if (regno >= 0)
 164     {
 165       fetch_register (regno);
 166     }
 167   else
 168     {
 169       for (regno = 0; regno < NUM_REGS; regno++)
 170         {
 171           fetch_register (regno);
 172         }
 173     }
 174 }
 175
 176 /* Store one register. */
 177
 178 static void
 179 store_register (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 (current_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 (int regno)
 226 {
 227   if (regno >= 0)
 228     {
 229       store_register (regno);
 230     }
 231   else
 232     {
 233       for (regno = 0; regno < NUM_REGS; regno++)
 234         {
 235           store_register (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 (elf_gregset_t *gregsetp)
 246 {
 247   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 248   int regi;
 249
 250   for (regi = M68K_D0_REGNUM; regi <= SP_REGNUM; regi++)
 251     regcache_raw_supply (current_regcache, regi, (char *) &regp[regmap[regi]]);
 252   regcache_raw_supply (current_regcache, PS_REGNUM, (char *) &regp[PT_SR]);
 253   regcache_raw_supply (current_regcache, PC_REGNUM, (char *) &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 (elf_gregset_t *gregsetp, int regno)
 261 {
 262   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 263   int i;
 264
 265   for (i = 0; i < NUM_GREGS; i++)
 266     if (regno == -1 || regno == i)
 267       regcache_raw_collect (current_regcache, i, regp + regmap[i]);
 268 }
 269
 270 #ifdef HAVE_PTRACE_GETREGS
 271
 272 /* Fetch all general-purpose registers from process/thread TID and
 273    store their values in GDB's register array.  */
 274
 275 static void
 276 fetch_regs (int tid)
 277 {
 278   elf_gregset_t regs;
 279
 280   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 281     {
 282       if (errno == EIO)
 283         {
 284           /* The kernel we're running on doesn't support the GETREGS
 285              request.  Reset `have_ptrace_getregs'.  */
 286           have_ptrace_getregs = 0;
 287           return;
 288         }
 289
 290       perror_with_name (_("Couldn't get registers"));
 291     }
 292
 293   supply_gregset (&regs);
 294 }
 295
 296 /* Store all valid general-purpose registers in GDB's register array
 297    into the process/thread specified by TID.  */
 298
 299 static void
 300 store_regs (int tid, int regno)
 301 {
 302   elf_gregset_t regs;
 303
 304   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 305     perror_with_name (_("Couldn't get registers"));
 306
 307   fill_gregset (&regs, regno);
 308
 309   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 310     perror_with_name (_("Couldn't write registers"));
 311 }
 312
 313 #else
 314
 315 static void fetch_regs (int tid) {}
 316 static void store_regs (int tid, int regno) {}
 317
 318 #endif
 319
 320 \f
 321 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 322
 323 /* What is the address of fpN within the floating-point register set F?  */
 324 #define FPREG_ADDR(f, n) ((char *) &(f)->fpregs[(n) * 3])
 325
 326 /* Fill GDB's register array with the floating-point register values in
 327    *FPREGSETP.  */
 328
 329 void
 330 supply_fpregset (elf_fpregset_t *fpregsetp)
 331 {
 332   int regi;
 333
 334   for (regi = FP0_REGNUM; regi < FP0_REGNUM + 8; regi++)
 335     regcache_raw_supply (current_regcache, regi,
 336                          FPREG_ADDR (fpregsetp, regi - FP0_REGNUM));
 337   regcache_raw_supply (current_regcache, M68K_FPC_REGNUM,
 338                        (char *) &fpregsetp->fpcntl[0]);
 339   regcache_raw_supply (current_regcache, M68K_FPS_REGNUM,
 340                        (char *) &fpregsetp->fpcntl[1]);
 341   regcache_raw_supply (current_regcache, M68K_FPI_REGNUM,
 342                        (char *) &fpregsetp->fpcntl[2]);
 343 }
 344
 345 /* Fill register REGNO (if it is a floating-point register) in
 346    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 347    do this for all registers.  */
 348
 349 void
 350 fill_fpregset (elf_fpregset_t *fpregsetp, int regno)
 351 {
 352   int i;
 353
 354   /* Fill in the floating-point registers.  */
 355   for (i = FP0_REGNUM; i < FP0_REGNUM + 8; i++)
 356     if (regno == -1 || regno == i)
 357       regcache_raw_collect (current_regcache, i,
 358                             FPREG_ADDR (fpregsetp, i - FP0_REGNUM));
 359
 360   /* Fill in the floating-point control registers.  */
 361   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 362     if (regno == -1 || regno == i)
 363       regcache_raw_collect (current_regcache, i,
 364                             (char *) &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 365 }
 366
 367 #ifdef HAVE_PTRACE_GETREGS
 368
 369 /* Fetch all floating-point registers from process/thread TID and store
 370    thier values in GDB's register array.  */
 371
 372 static void
 373 fetch_fpregs (int tid)
 374 {
 375   elf_fpregset_t fpregs;
 376
 377   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 378     perror_with_name (_("Couldn't get floating point status"));
 379
 380   supply_fpregset (&fpregs);
 381 }
 382
 383 /* Store all valid floating-point registers in GDB's register array
 384    into the process/thread specified by TID.  */
 385
 386 static void
 387 store_fpregs (int tid, int regno)
 388 {
 389   elf_fpregset_t fpregs;
 390
 391   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 392     perror_with_name (_("Couldn't get floating point status"));
 393
 394   fill_fpregset (&fpregs, regno);
 395
 396   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 397     perror_with_name (_("Couldn't write floating point status"));
 398 }
 399
 400 #else
 401
 402 static void fetch_fpregs (int tid) {}
 403 static void store_fpregs (int tid, int regno) {}
 404
 405 #endif
 406 \f
 407 /* Transferring arbitrary registers between GDB and inferior.  */
 408
 409 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 410    this for all registers (including the floating point and SSE
 411    registers).  */
 412
 413 static void
 414 m68k_linux_fetch_inferior_registers (int regno)
 415 {
 416   int tid;
 417
 418   /* Use the old method of peeking around in `struct user' if the
 419      GETREGS request isn't available.  */
 420   if (! have_ptrace_getregs)
 421     {
 422       old_fetch_inferior_registers (regno);
 423       return;
 424     }
 425
 426   /* GNU/Linux LWP ID's are process ID's.  */
 427   tid = TIDGET (inferior_ptid);
 428   if (tid == 0)
 429     tid = PIDGET (inferior_ptid);               /* Not a threaded program.  */
 430
 431   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 432      transfers more registers in one system call, and we'll cache the
 433      results.  But remember that fetch_fpxregs can fail, and return
 434      zero.  */
 435   if (regno == -1)
 436     {
 437       fetch_regs (tid);
 438
 439       /* The call above might reset `have_ptrace_getregs'.  */
 440       if (! have_ptrace_getregs)
 441         {
 442           old_fetch_inferior_registers (-1);
 443           return;
 444         }
 445
 446       fetch_fpregs (tid);
 447       return;
 448     }
 449
 450   if (getregs_supplies (regno))
 451     {
 452       fetch_regs (tid);
 453       return;
 454     }
 455
 456   if (getfpregs_supplies (regno))
 457     {
 458       fetch_fpregs (tid);
 459       return;
 460     }
 461
 462   internal_error (__FILE__, __LINE__,
 463                   _("Got request for bad register number %d."), regno);
 464 }
 465
 466 /* Store register REGNO back into the child process.  If REGNO is -1,
 467    do this for all registers (including the floating point and SSE
 468    registers).  */
 469 static void
 470 m68k_linux_store_inferior_registers (int regno)
 471 {
 472   int tid;
 473
 474   /* Use the old method of poking around in `struct user' if the
 475      SETREGS request isn't available.  */
 476   if (! have_ptrace_getregs)
 477     {
 478       old_store_inferior_registers (regno);
 479       return;
 480     }
 481
 482   /* GNU/Linux LWP ID's are process ID's.  */
 483   tid = TIDGET (inferior_ptid);
 484   if (tid == 0)
 485     tid = PIDGET (inferior_ptid);       /* Not a threaded program.  */
 486
 487   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 488      transfers more registers in one system call.  But remember that
 489      store_fpregs can fail, and return zero.  */
 490   if (regno == -1)
 491     {
 492       store_regs (tid, regno);
 493       store_fpregs (tid, regno);
 494       return;
 495     }
 496
 497   if (getregs_supplies (regno))
 498     {
 499       store_regs (tid, regno);
 500       return;
 501     }
 502
 503   if (getfpregs_supplies (regno))
 504     {
 505       store_fpregs (tid, regno);
 506       return;
 507     }
 508
 509   internal_error (__FILE__, __LINE__,
 510                   _("Got request to store bad register number %d."), regno);
 511 }
 512 \f
 513 /* Interpreting register set info found in core files.  */
 514
 515 /* Provide registers to GDB from a core file.
 516
 517    (We can't use the generic version of this function in
 518    core-regset.c, because we need to use elf_gregset_t instead of
 519    gregset_t.)
 520
 521    CORE_REG_SECT points to an array of bytes, which are the contents
 522    of a `note' from a core file which BFD thinks might contain
 523    register contents.  CORE_REG_SIZE is its size.
 524
 525    WHICH says which register set corelow suspects this is:
 526      0 --- the general-purpose register set, in elf_gregset_t format
 527      2 --- the floating-point register set, in elf_fpregset_t format
 528
 529    REG_ADDR isn't used on GNU/Linux.  */
 530
 531 static void
 532 fetch_core_registers (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 (&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 (&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 }