gdb/m68k-linux-nat.c

   1 /* Motorola m68k native support for GNU/Linux.
   2
   3    Copyright (C) 1996-2019 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 #include "inf-ptrace.h"
  55
  56 #ifndef PTRACE_GET_THREAD_AREA
  57 #define PTRACE_GET_THREAD_AREA 25
  58 #endif
  59 \f
  60
  61 class m68k_linux_nat_target final : public linux_nat_target
  62 {
  63 public:
  64   /* Add our register access methods.  */
  65   void fetch_registers (struct regcache *, int) override;
  66   void store_registers (struct regcache *, int) override;
  67 };
  68
  69 static m68k_linux_nat_target the_m68k_linux_nat_target;
  70
  71 /* This table must line up with gdbarch_register_name in "m68k-tdep.c".  */
  72 static const int regmap[] =
  73 {
  74   PT_D0, PT_D1, PT_D2, PT_D3, PT_D4, PT_D5, PT_D6, PT_D7,
  75   PT_A0, PT_A1, PT_A2, PT_A3, PT_A4, PT_A5, PT_A6, PT_USP,
  76   PT_SR, PT_PC,
  77   /* PT_FP0, ..., PT_FP7 */
  78   21, 24, 27, 30, 33, 36, 39, 42,
  79   /* PT_FPCR, PT_FPSR, PT_FPIAR */
  80   45, 46, 47
  81 };
  82
  83 /* Which ptrace request retrieves which registers?
  84    These apply to the corresponding SET requests as well.  */
  85 #define NUM_GREGS (18)
  86 #define MAX_NUM_REGS (NUM_GREGS + 11)
  87
  88 static int
  89 getregs_supplies (int regno)
  90 {
  91   return 0 <= regno && regno < NUM_GREGS;
  92 }
  93
  94 static int
  95 getfpregs_supplies (int regno)
  96 {
  97   return M68K_FP0_REGNUM <= regno && regno <= M68K_FPI_REGNUM;
  98 }
  99
 100 /* Does the current host support the GETREGS request?  */
 101 static int have_ptrace_getregs =
 102 #ifdef HAVE_PTRACE_GETREGS
 103   1
 104 #else
 105   0
 106 #endif
 107 ;
 108
 109 \f
 110
 111 /* Fetching registers directly from the U area, one at a time.  */
 112
 113 /* Fetch one register.  */
 114
 115 static void
 116 fetch_register (struct regcache *regcache, int regno)
 117 {
 118   struct gdbarch *gdbarch = regcache->arch ();
 119   long regaddr, val;
 120   int i;
 121   gdb_byte buf[M68K_MAX_REGISTER_SIZE];
 122   pid_t tid = get_ptrace_pid (regcache->ptid ());
 123
 124   regaddr = 4 * regmap[regno];
 125   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 126     {
 127       errno = 0;
 128       val = ptrace (PTRACE_PEEKUSER, tid, regaddr, 0);
 129       memcpy (&buf[i], &val, sizeof (long));
 130       regaddr += sizeof (long);
 131       if (errno != 0)
 132         error (_("Couldn't read register %s (#%d): %s."),
 133                gdbarch_register_name (gdbarch, regno),
 134                regno, safe_strerror (errno));
 135     }
 136   regcache->raw_supply (regno, buf);
 137 }
 138
 139 /* Fetch register values from the inferior.
 140    If REGNO is negative, do this for all registers.
 141    Otherwise, REGNO specifies which register (so we can save time).  */
 142
 143 static void
 144 old_fetch_inferior_registers (struct regcache *regcache, int regno)
 145 {
 146   if (regno >= 0)
 147     {
 148       fetch_register (regcache, regno);
 149     }
 150   else
 151     {
 152       for (regno = 0;
 153            regno < gdbarch_num_regs (regcache->arch ());
 154            regno++)
 155         {
 156           fetch_register (regcache, regno);
 157         }
 158     }
 159 }
 160
 161 /* Store one register.  */
 162
 163 static void
 164 store_register (const struct regcache *regcache, int regno)
 165 {
 166   struct gdbarch *gdbarch = regcache->arch ();
 167   long regaddr, val;
 168   int i;
 169   gdb_byte buf[M68K_MAX_REGISTER_SIZE];
 170   pid_t tid = get_ptrace_pid (regcache->ptid ());
 171
 172   regaddr = 4 * regmap[regno];
 173
 174   /* Put the contents of regno into a local buffer.  */
 175   regcache->raw_collect (regno, buf);
 176
 177   /* Store the local buffer into the inferior a chunk at the time.  */
 178   for (i = 0; i < register_size (gdbarch, regno); i += sizeof (long))
 179     {
 180       errno = 0;
 181       memcpy (&val, &buf[i], sizeof (long));
 182       ptrace (PTRACE_POKEUSER, tid, regaddr, val);
 183       regaddr += sizeof (long);
 184       if (errno != 0)
 185         error (_("Couldn't write register %s (#%d): %s."),
 186                gdbarch_register_name (gdbarch, regno),
 187                regno, safe_strerror (errno));
 188     }
 189 }
 190
 191 /* Store our register values back into the inferior.
 192    If REGNO is negative, do this for all registers.
 193    Otherwise, REGNO specifies which register (so we can save time).  */
 194
 195 static void
 196 old_store_inferior_registers (const struct regcache *regcache, int regno)
 197 {
 198   if (regno >= 0)
 199     {
 200       store_register (regcache, regno);
 201     }
 202   else
 203     {
 204       for (regno = 0;
 205            regno < gdbarch_num_regs (regcache->arch ());
 206            regno++)
 207         {
 208           store_register (regcache, regno);
 209         }
 210     }
 211 }
 212 \f
 213 /*  Given a pointer to a general register set in /proc format
 214    (elf_gregset_t *), unpack the register contents and supply
 215    them as gdb's idea of the current register values.  */
 216
 217 void
 218 supply_gregset (struct regcache *regcache, const elf_gregset_t *gregsetp)
 219 {
 220   struct gdbarch *gdbarch = regcache->arch ();
 221   const elf_greg_t *regp = (const elf_greg_t *) gregsetp;
 222   int regi;
 223
 224   for (regi = M68K_D0_REGNUM;
 225        regi <= gdbarch_sp_regnum (gdbarch);
 226        regi++)
 227     regcache->raw_supply (regi, &regp[regmap[regi]]);
 228   regcache->raw_supply (gdbarch_ps_regnum (gdbarch), &regp[PT_SR]);
 229   regcache->raw_supply (gdbarch_pc_regnum (gdbarch), &regp[PT_PC]);
 230 }
 231
 232 /* Fill register REGNO (if it is a general-purpose register) in
 233    *GREGSETPS with the value in GDB's register array.  If REGNO is -1,
 234    do this for all registers.  */
 235 void
 236 fill_gregset (const struct regcache *regcache,
 237               elf_gregset_t *gregsetp, int regno)
 238 {
 239   elf_greg_t *regp = (elf_greg_t *) gregsetp;
 240   int i;
 241
 242   for (i = 0; i < NUM_GREGS; i++)
 243     if (regno == -1 || regno == i)
 244       regcache->raw_collect (i, regp + regmap[i]);
 245 }
 246
 247 #ifdef HAVE_PTRACE_GETREGS
 248
 249 /* Fetch all general-purpose registers from process/thread TID and
 250    store their values in GDB's register array.  */
 251
 252 static void
 253 fetch_regs (struct regcache *regcache, int tid)
 254 {
 255   elf_gregset_t regs;
 256
 257   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 258     {
 259       if (errno == EIO)
 260         {
 261           /* The kernel we're running on doesn't support the GETREGS
 262              request.  Reset `have_ptrace_getregs'.  */
 263           have_ptrace_getregs = 0;
 264           return;
 265         }
 266
 267       perror_with_name (_("Couldn't get registers"));
 268     }
 269
 270   supply_gregset (regcache, (const elf_gregset_t *) &regs);
 271 }
 272
 273 /* Store all valid general-purpose registers in GDB's register array
 274    into the process/thread specified by TID.  */
 275
 276 static void
 277 store_regs (const struct regcache *regcache, int tid, int regno)
 278 {
 279   elf_gregset_t regs;
 280
 281   if (ptrace (PTRACE_GETREGS, tid, 0, (int) &regs) < 0)
 282     perror_with_name (_("Couldn't get registers"));
 283
 284   fill_gregset (regcache, &regs, regno);
 285
 286   if (ptrace (PTRACE_SETREGS, tid, 0, (int) &regs) < 0)
 287     perror_with_name (_("Couldn't write registers"));
 288 }
 289
 290 #else
 291
 292 static void fetch_regs (struct regcache *regcache, int tid)
 293 {
 294 }
 295
 296 static void store_regs (const struct regcache *regcache, int tid, int regno)
 297 {
 298 }
 299
 300 #endif
 301
 302 \f
 303 /* Transfering floating-point registers between GDB, inferiors and cores.  */
 304
 305 /* What is the address of fpN within the floating-point register set F?  */
 306 #define FPREG_ADDR(f, n) (&(f)->fpregs[(n) * 3])
 307
 308 /* Fill GDB's register array with the floating-point register values in
 309    *FPREGSETP.  */
 310
 311 void
 312 supply_fpregset (struct regcache *regcache, const elf_fpregset_t *fpregsetp)
 313 {
 314   struct gdbarch *gdbarch = regcache->arch ();
 315   int regi;
 316
 317   for (regi = gdbarch_fp0_regnum (gdbarch);
 318        regi < gdbarch_fp0_regnum (gdbarch) + 8; regi++)
 319     regcache->raw_supply
 320       (regi, FPREG_ADDR (fpregsetp, regi - gdbarch_fp0_regnum (gdbarch)));
 321   regcache->raw_supply (M68K_FPC_REGNUM, &fpregsetp->fpcntl[0]);
 322   regcache->raw_supply (M68K_FPS_REGNUM, &fpregsetp->fpcntl[1]);
 323   regcache->raw_supply (M68K_FPI_REGNUM, &fpregsetp->fpcntl[2]);
 324 }
 325
 326 /* Fill register REGNO (if it is a floating-point register) in
 327    *FPREGSETP with the value in GDB's register array.  If REGNO is -1,
 328    do this for all registers.  */
 329
 330 void
 331 fill_fpregset (const struct regcache *regcache,
 332                elf_fpregset_t *fpregsetp, int regno)
 333 {
 334   struct gdbarch *gdbarch = regcache->arch ();
 335   int i;
 336
 337   /* Fill in the floating-point registers.  */
 338   for (i = gdbarch_fp0_regnum (gdbarch);
 339        i < gdbarch_fp0_regnum (gdbarch) + 8; i++)
 340     if (regno == -1 || regno == i)
 341       regcache->raw_collect
 342         (i, FPREG_ADDR (fpregsetp, i - gdbarch_fp0_regnum (gdbarch)));
 343
 344   /* Fill in the floating-point control registers.  */
 345   for (i = M68K_FPC_REGNUM; i <= M68K_FPI_REGNUM; i++)
 346     if (regno == -1 || regno == i)
 347       regcache->raw_collect (i, &fpregsetp->fpcntl[i - M68K_FPC_REGNUM]);
 348 }
 349
 350 #ifdef HAVE_PTRACE_GETREGS
 351
 352 /* Fetch all floating-point registers from process/thread TID and store
 353    thier values in GDB's register array.  */
 354
 355 static void
 356 fetch_fpregs (struct regcache *regcache, int tid)
 357 {
 358   elf_fpregset_t fpregs;
 359
 360   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 361     perror_with_name (_("Couldn't get floating point status"));
 362
 363   supply_fpregset (regcache, (const elf_fpregset_t *) &fpregs);
 364 }
 365
 366 /* Store all valid floating-point registers in GDB's register array
 367    into the process/thread specified by TID.  */
 368
 369 static void
 370 store_fpregs (const struct regcache *regcache, int tid, int regno)
 371 {
 372   elf_fpregset_t fpregs;
 373
 374   if (ptrace (PTRACE_GETFPREGS, tid, 0, (int) &fpregs) < 0)
 375     perror_with_name (_("Couldn't get floating point status"));
 376
 377   fill_fpregset (regcache, &fpregs, regno);
 378
 379   if (ptrace (PTRACE_SETFPREGS, tid, 0, (int) &fpregs) < 0)
 380     perror_with_name (_("Couldn't write floating point status"));
 381 }
 382
 383 #else
 384
 385 static void fetch_fpregs (struct regcache *regcache, int tid)
 386 {
 387 }
 388
 389 static void store_fpregs (const struct regcache *regcache, int tid, int regno)
 390 {
 391 }
 392
 393 #endif
 394 \f
 395 /* Transferring arbitrary registers between GDB and inferior.  */
 396
 397 /* Fetch register REGNO from the child process.  If REGNO is -1, do
 398    this for all registers (including the floating point and SSE
 399    registers).  */
 400
 401 void
 402 m68k_linux_nat_target::fetch_registers (struct regcache *regcache, int regno)
 403 {
 404   pid_t tid;
 405
 406   /* Use the old method of peeking around in `struct user' if the
 407      GETREGS request isn't available.  */
 408   if (! have_ptrace_getregs)
 409     {
 410       old_fetch_inferior_registers (regcache, regno);
 411       return;
 412     }
 413
 414   tid = get_ptrace_pid (regcache->ptid ());
 415
 416   /* Use the PTRACE_GETFPXREGS request whenever possible, since it
 417      transfers more registers in one system call, and we'll cache the
 418      results.  But remember that fetch_fpxregs can fail, and return
 419      zero.  */
 420   if (regno == -1)
 421     {
 422       fetch_regs (regcache, tid);
 423
 424       /* The call above might reset `have_ptrace_getregs'.  */
 425       if (! have_ptrace_getregs)
 426         {
 427           old_fetch_inferior_registers (regcache, -1);
 428           return;
 429         }
 430
 431       fetch_fpregs (regcache, tid);
 432       return;
 433     }
 434
 435   if (getregs_supplies (regno))
 436     {
 437       fetch_regs (regcache, tid);
 438       return;
 439     }
 440
 441   if (getfpregs_supplies (regno))
 442     {
 443       fetch_fpregs (regcache, tid);
 444       return;
 445     }
 446
 447   internal_error (__FILE__, __LINE__,
 448                   _("Got request for bad register number %d."), regno);
 449 }
 450
 451 /* Store register REGNO back into the child process.  If REGNO is -1,
 452    do this for all registers (including the floating point and SSE
 453    registers).  */
 454 void
 455 m68k_linux_nat_target::store_registers (struct regcache *regcache, int regno)
 456 {
 457   pid_t tid;
 458
 459   /* Use the old method of poking around in `struct user' if the
 460      SETREGS request isn't available.  */
 461   if (! have_ptrace_getregs)
 462     {
 463       old_store_inferior_registers (regcache, regno);
 464       return;
 465     }
 466
 467   tid = get_ptrace_pid (regcache->ptid ());
 468
 469   /* Use the PTRACE_SETFPREGS requests whenever possible, since it
 470      transfers more registers in one system call.  But remember that
 471      store_fpregs can fail, and return zero.  */
 472   if (regno == -1)
 473     {
 474       store_regs (regcache, tid, regno);
 475       store_fpregs (regcache, tid, regno);
 476       return;
 477     }
 478
 479   if (getregs_supplies (regno))
 480     {
 481       store_regs (regcache, tid, regno);
 482       return;
 483     }
 484
 485   if (getfpregs_supplies (regno))
 486     {
 487       store_fpregs (regcache, tid, regno);
 488       return;
 489     }
 490
 491   internal_error (__FILE__, __LINE__,
 492                   _("Got request to store bad register number %d."), regno);
 493 }
 494 \f
 495
 496 /* Fetch the thread-local storage pointer for libthread_db.  */
 497
 498 ps_err_e
 499 ps_get_thread_area (struct ps_prochandle *ph,
 500                     lwpid_t lwpid, int idx, void **base)
 501 {
 502   if (ptrace (PTRACE_GET_THREAD_AREA, lwpid, NULL, base) < 0)
 503     return PS_ERR;
 504
 505   /* IDX is the bias from the thread pointer to the beginning of the
 506      thread descriptor.  It has to be subtracted due to implementation
 507      quirks in libthread_db.  */
 508   *base = (char *) *base - idx;
 509
 510   return PS_OK;
 511 }
 512
 513 void
 514 _initialize_m68k_linux_nat (void)
 515 {
 516   /* Register the target.  */
 517   linux_target = &the_m68k_linux_nat_target;
 518   add_inf_child_target (&the_m68k_linux_nat_target);
 519 }