gdb/m68k-linux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright (C) 1996-2016 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include "defs.h"
  21 #include "frame.h"
  22 #include "inferior.h"
  23 #include "language.h"
  24 #include "gdbcore.h"
  25 #include "regcache.h"
  26 #include "target.h"
  27 #include "linux-nat.h"
  28
  29 #include "m68k-tdep.h"
  30
  31 #include <sys/dir.h>
  32 #include <signal.h>
  33 #include "nat/gdb_ptrace.h"
  34 #include <sys/user.h>
  35 #include <sys/ioctl.h>
  36 #include <fcntl.h>
  37 #include <sys/procfs.h>
  38
  39 #ifdef HAVE_SYS_REG_H
  40 #include <sys/reg.h>
  41 #endif
  42
  43 #include <sys/file.h>
  44 #include <sys/stat.h>
  45
  46 #include "floatformat.h"
  47
  48 /* Prototypes for supply_gregset etc.  */
  49 #include "gregset.h"
  50
  51 /* Defines ps_err_e, struct ps_prochandle.  */
  52 #include "gdb_proc_service.h"
  53
  54 #ifndef PTRACE_GET_THREAD_AREA
  55 #define PTRACE_GET_THREAD_AREA 25
  56 #endif
  57 \f
  58 /* This table must line up with gdbarch_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 static int
  76 getregs_supplies (int regno)
  77 {
  78   return 0 <= regno && regno < NUM_GREGS;
  79 }
  80
  81 static int
  82 getfpregs_supplies (int regno)
  83 {
  84   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  85 }
  86
  87 /* Does the current host support the GETREGS request?  */
  88 static 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 /* Fetch one register.  */
 101
 102 static void
 103 fetch_register (struct regcache *regcache, int regno)
 104 {
 105   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 106   long regaddr, val;
 107   int i;
 108   gdb_byte buf[MAX_REGISTER_SIZE];
 109   int tid;
 110
 111   /* Overload thread id onto process id.  */
 112   tid = ptid_get_lwp (inferior_ptid);
 113   if (tid == 0)
 114     tid = ptid_get_pid (inferior_ptid); /* no thread id, just use
 115                                            process id.  */
 116
 117   regaddr = 4 * regmap[regno];
 118   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 119     {
 120       errno = 0;
 121       val = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 122       memcpy (&buf[i], &val, sizeof (long));
 123       regaddr += sizeof (long);
 124       if (errno != 0)
 125         error (_("Couldn't read register %s (#%d): %s."),
 126                gdbarch_register_name (gdbarch, regno),
 127                regno, safe_strerror (errno));
 128     }
 129   regcache_raw_supply (regcache, regno, buf);
 130 }
 131
 132 /* Fetch register values from the inferior.
 133    If REGNO is negative, do this for all registers.
 134    Otherwise, REGNO specifies which register (so we can save time).  */
 135
 136 static void
 137 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 138 {
 139   if (regno >= 0)
 140     {
 141       fetch_register (regcache, regno);
 142     }
 143   else
 144     {
 145       for (regno = 0;
 146            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 147            regno++)
 148         {
 149           fetch_register (regcache, regno);
 150         }
 151     }
 152 }
 153
 154 /* Store one register.  */
 155
 156 static void
 157 store_register (const struct regcache *regcache, int regno)
 158 {
 159   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 160   long regaddr, val;
 161   int i;
 162   int tid;
 163   gdb_byte buf[MAX_REGISTER_SIZE];
 164
 165   /* Overload thread id onto process id.  */
 166   tid = ptid_get_lwp (inferior_ptid);
 167   if (tid == 0)
 168     tid = ptid_get_pid (inferior_ptid); /* no thread id, just use
 169                                            process id.  */
 170
 171   regaddr = 4 * regmap[regno];
 172
 173   /* Put the contents of regno into a local buffer.  */
 174   regcache_raw_collect (regcache, regno, buf);
 175
 176   /* Store the local buffer into the inferior a chunk at the time.  */
 177   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 178     {
 179       errno = 0;
 180       memcpy (&val, &buf[i], sizeof (long));
 181       ptrace (PTRACE_POKEUSER, tid, regaddr, val);
 182       regaddr += sizeof (long);
 183       if (errno != 0)
 184         error (_("Couldn't write register %s (#%d): %s."),
 185                gdbarch_register_name (gdbarch, regno),
 186                regno, safe_strerror (errno));
 187     }
 188 }
 189
 190 /* Store our register values back into the inferior.
 191    If REGNO is negative, do this for all registers.
 192    Otherwise, REGNO specifies which register (so we can save time).  */
 193
 194 static void
 195 old_store_inferior_registers (const struct regcache *regcache, int regno)
 196 {
 197   if (regno >= 0)
 198     {
 199       store_register (regcache, regno);
 200     }
 201   else
 202     {
 203       for (regno = 0;
 204            regno < gdbarch_num_regs (get_regcache_arch (regcache));
 205            regno++)
 206         {
 207           store_register (regcache, regno);
 208         }
 209     }
 210 }
 211 \f
 212 /*  Given a pointer to a general register set in /proc format
 213    (elf_gregset_t *), unpack the register contents and supply
 214    them as gdb's idea of the current register values.  */
 215
 216 void
 217 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 218 {
 219   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 220   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 221   int regi;
 222
 223   for (regi = M68K_D0_REGNUM;
 224        regi <= gdbarch_sp_regnum (gdbarch);
 225        regi++)
 226     regcache_raw_supply (regcache, regi, &regp[regmap[regi]]);
 227   regcache_raw_supply (regcache, gdbarch_ps_regnum (gdbarch),
 228                        &regp[PT_SR]);
 229   regcache_raw_supply (regcache,
 230                        gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 231 }
 232
 233 /* Fill register REGNO (if it is a general-purpose register) in
 234    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 235    do this for all registers.  */
 236 void
 237 fill_gregset (const struct regcache *regcache,
 238               elf_gregset_t *gregsetp, int regno)
 239 {
 240   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 241   int i;
 242
 243   for (i = 0; i < NUM_GREGS; i++)
 244     if (regno == -1 || regno == i)
 245       regcache_raw_collect (regcache, i, regp + regmap[i]);
 246 }
 247
 248 #ifdef HAVE_PTRACE_GETREGS
 249
 250 /* Fetch all general-purpose registers from process/thread TID and
 251    store their values in GDB's register array.  */
 252
 253 static void
 254 fetch_regs (struct regcache *regcache, int tid)
 255 {
 256   elf_gregset_t regs;
 257
 258   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 259     {
 260       if (errno == EIO)
 261         {
 262           /* The kernel we're running on doesn't support the GETREGS
 263              request.  Reset `have_ptrace_getregs'.  */
 264           have_ptrace_getregs = 0;
 265           return;
 266         }
 267
 268       perror_with_name (_("Couldn't get registers"));
 269     }
 270
 271   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 272 }
 273
 274 /* Store all valid general-purpose registers in GDB's register array
 275    into the process/thread specified by TID.  */
 276
 277 static void
 278 store_regs (const struct regcache *regcache, int tid, int regno)
 279 {
 280   elf_gregset_t regs;
 281
 282   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 283     perror_with_name (_("Couldn't get registers"));
 284
 285   fill_gregset (regcache, &regs, regno);
 286
 287   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 288     perror_with_name (_("Couldn't write registers"));
 289 }
 290
 291 #else
 292
 293 static void fetch_regs (struct regcache *regcache, int tid)
 294 {
 295 }
 296
 297 static void store_regs (const struct regcache *regcache, int tid, int regno)
 298 {
 299 }
 300
 301 #endif
 302
 303 \f
 304 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 305
 306 /* What is the address of fpN within the floating-point register set F?  */
 307 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 308
 309 /* Fill GDB's register array with the floating-point register values in
 310    *FPREGSETP.  */
 311
 312 void
 313 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 314 {
 315   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 316   int regi;
 317
 318   for (regi = gdbarch_fp0_regnum (gdbarch);
 319        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 320     regcache_raw_supply (regcache, regi,
 321                          FPREG_ADDR (fpregsetp,
 322                                      regi - gdbarch_fp0_regnum (gdbarch)));
 323   regcache_raw_supply (regcache, M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 324   regcache_raw_supply (regcache, M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 325   regcache_raw_supply (regcache, M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 326 }
 327
 328 /* Fill register REGNO (if it is a floating-point register) in
 329    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 330    do this for all registers.  */
 331
 332 void
 333 fill_fpregset (const struct regcache *regcache,
 334                elf_fpregset_t *fpregsetp, int regno)
 335 {
 336   struct gdbarch *gdbarch = get_regcache_arch (regcache);
 337   int i;
 338
 339   /* Fill in the floating-point registers.  */
 340   for (i = gdbarch_fp0_regnum (gdbarch);
 341        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 342     if (regno == -1 || regno == i)
 343       regcache_raw_collect (regcache, i,
 344                             FPREG_ADDR (fpregsetp,
 345                                         i - gdbarch_fp0_regnum (gdbarch)));
 346
 347   /* Fill in the floating-point control registers.  */
 348   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 349     if (regno == -1 || regno == i)
 350       regcache_raw_collect (regcache, i,
 351                             &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 352 }
 353
 354 #ifdef HAVE_PTRACE_GETREGS
 355
 356 /* Fetch all floating-point registers from process/thread TID and store
 357    thier values in GDB's register array.  */
 358
 359 static void
 360 fetch_fpregs (struct regcache *regcache, int tid)
 361 {
 362   elf_fpregset_t fpregs;
 363
 364   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 365     perror_with_name (_("Couldn't get floating point status"));
 366
 367   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 368 }
 369
 370 /* Store all valid floating-point registers in GDB's register array
 371    into the process/thread specified by TID.  */
 372
 373 static void
 374 store_fpregs (const struct regcache *regcache, int tid, int regno)
 375 {
 376   elf_fpregset_t fpregs;
 377
 378   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 379     perror_with_name (_("Couldn't get floating point status"));
 380
 381   fill_fpregset (regcache, &fpregs, regno);
 382
 383   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 384     perror_with_name (_("Couldn't write floating point status"));
 385 }
 386
 387 #else
 388
 389 static void fetch_fpregs (struct regcache *regcache, int tid)
 390 {
 391 }
 392
 393 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 394 {
 395 }
 396
 397 #endif
 398 \f
 399 /* Transferring arbitrary registers between GDB and inferior.  */
 400
 401 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 402    this for all registers (including the floating point and SSE
 403    registers).  */
 404
 405 static void
 406 m68k_linux_fetch_inferior_registers (struct target_ops *ops,
 407                                      struct regcache *regcache, int regno)
 408 {
 409   int tid;
 410
 411   /* Use the old method of peeking around in `struct user' if the
 412      GETREGS request isn't available.  */
 413   if (! have_ptrace_getregs)
 414     {
 415       old_fetch_inferior_registers (regcache, regno);
 416       return;
 417     }
 418
 419   /* GNU/Linux LWP ID's are process ID's.  */
 420   tid = ptid_get_lwp (inferior_ptid);
 421   if (tid == 0)
 422     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 423
 424   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 425      transfers more registers in one system call, and we'll cache the
 426      results.  But remember that fetch_fpxregs can fail, and return
 427      zero.  */
 428   if (regno == -1)
 429     {
 430       fetch_regs (regcache, tid);
 431
 432       /* The call above might reset `have_ptrace_getregs'.  */
 433       if (! have_ptrace_getregs)
 434         {
 435           old_fetch_inferior_registers (regcache, -1);
 436           return;
 437         }
 438
 439       fetch_fpregs (regcache, tid);
 440       return;
 441     }
 442
 443   if (getregs_supplies (regno))
 444     {
 445       fetch_regs (regcache, tid);
 446       return;
 447     }
 448
 449   if (getfpregs_supplies (regno))
 450     {
 451       fetch_fpregs (regcache, tid);
 452       return;
 453     }
 454
 455   internal_error (__FILE__, __LINE__,
 456                   _("Got request for bad register number %d."), regno);
 457 }
 458
 459 /* Store register REGNO back into the child process.  If REGNO is -1,
 460    do this for all registers (including the floating point and SSE
 461    registers).  */
 462 static void
 463 m68k_linux_store_inferior_registers (struct target_ops *ops,
 464                                      struct regcache *regcache, int regno)
 465 {
 466   int tid;
 467
 468   /* Use the old method of poking around in `struct user' if the
 469      SETREGS request isn't available.  */
 470   if (! have_ptrace_getregs)
 471     {
 472       old_store_inferior_registers (regcache, regno);
 473       return;
 474     }
 475
 476   /* GNU/Linux LWP ID's are process ID's.  */
 477   tid = ptid_get_lwp (inferior_ptid);
 478   if (tid == 0)
 479     tid = ptid_get_pid (inferior_ptid); /* Not a threaded program.  */
 480
 481   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 482      transfers more registers in one system call.  But remember that
 483      store_fpregs can fail, and return zero.  */
 484   if (regno == -1)
 485     {
 486       store_regs (regcache, tid, regno);
 487       store_fpregs (regcache, tid, regno);
 488       return;
 489     }
 490
 491   if (getregs_supplies (regno))
 492     {
 493       store_regs (regcache, tid, regno);
 494       return;
 495     }
 496
 497   if (getfpregs_supplies (regno))
 498     {
 499       store_fpregs (regcache, tid, regno);
 500       return;
 501     }
 502
 503   internal_error (__FILE__, __LINE__,
 504                   _("Got request to store bad register number %d."), regno);
 505 }
 506 \f
 507
 508 /* Fetch the thread-local storage pointer for libthread_db.  */
 509
 510 ps_err_e
 511 ps_get_thread_area (struct ps_prochandle *ph,
 512                     lwpid_t lwpid, int idx, void **base)
 513 {
 514   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) < 0)
 515     return PS_ERR;
 516
 517   /* IDX is the bias from the thread pointer to the beginning of the
 518      thread descriptor.  It has to be subtracted due to implementation
 519      quirks in libthread_db.  */
 520   *base = (char *) *base - idx;
 521
 522   return PS_OK;
 523 }
 524 \f
 525
 526 void _initialize_m68k_linux_nat (void);
 527
 528 void
 529 _initialize_m68k_linux_nat (void)
 530 {
 531   struct target_ops *t;
 532
 533   /* Fill in the generic GNU/Linux methods.  */
 534   t = linux_target ();
 535
 536   /* Add our register access methods.  */
 537   t->to_fetch_registers = m68k_linux_fetch_inferior_registers;
 538   t->to_store_registers = m68k_linux_store_inferior_registers;
 539
 540   /* Register the target.  */
 541   linux_nat_add_target (t);
 542 }