gdb/gdbserver/regcache.c

   1 /* Register support routines for the remote server for GDB.
   2    Copyright (C) 2001-2018 Free Software Foundation, Inc.
   3
   4    This file is part of GDB.
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  18
  19 #include "server.h"
  20 #include "regdef.h"
  21 #include "gdbthread.h"
  22 #include "tdesc.h"
  23 #include "rsp-low.h"
  24 #ifndef IN_PROCESS_AGENT
  25
  26 struct regcache *
  27 get_thread_regcache (struct thread_info *thread, int fetch)
  28 {
  29   struct regcache *regcache;
  30
  31   /* Check the target descriptor is still valid for the current target.  If
  32      not, then clear it and create a new one.  */
  33   if (!target_validate_tdesc (thread))
  34     {
  35       /* Clear regcache.  */
  36       free_register_cache (thread_regcache_data (thread));
  37       set_thread_regcache_data (thread, NULL);
  38       regcache = NULL;
  39
  40       target_arch_setup ();
  41     }
  42
  43   regcache = thread_regcache_data (thread);
  44
  45   /* Threads' regcaches are created lazily, because biarch targets add
  46      the main thread/lwp before seeing it stop for the first time, and
  47      it is only after the target sees the thread stop for the first
  48      time that the target has a chance of determining the process's
  49      architecture.  IOW, when we first add the process's main thread
  50      we don't know which architecture/tdesc its regcache should
  51      have.  */
  52   if (regcache == NULL)
  53     {
  54       struct process_info *proc = get_thread_process (thread);
  55
  56       gdb_assert (proc->tdesc != NULL);
  57
  58       regcache = new_register_cache (proc->tdesc);
  59       set_thread_regcache_data (thread, regcache);
  60     }
  61
  62   if (fetch && regcache->registers_valid == 0)
  63     {
  64       struct thread_info *saved_thread = current_thread;
  65
  66       current_thread = thread;
  67       /* Invalidate all registers, to prevent stale left-overs.  */
  68       memset (regcache->register_status, REG_UNAVAILABLE,
  69               regcache->tdesc->reg_defs.size ());
  70       fetch_inferior_registers (regcache, -1);
  71       current_thread = saved_thread;
  72       regcache->registers_valid = 1;
  73     }
  74
  75   return regcache;
  76 }
  77
  78 /* See common/common-regcache.h.  */
  79
  80 struct regcache *
  81 get_thread_regcache_for_ptid (ptid_t ptid)
  82 {
  83   return get_thread_regcache (find_thread_ptid (ptid), 1);
  84 }
  85
  86 void
  87 regcache_invalidate_thread (struct thread_info *thread)
  88 {
  89   struct regcache *regcache;
  90
  91   regcache = thread_regcache_data (thread);
  92
  93   if (regcache == NULL)
  94     return;
  95
  96   if (regcache->registers_valid)
  97     {
  98       struct thread_info *saved_thread = current_thread;
  99
 100       current_thread = thread;
 101       store_inferior_registers (regcache, -1);
 102       current_thread = saved_thread;
 103     }
 104
 105   regcache->registers_valid = 0;
 106 }
 107
 108 /* See regcache.h.  */
 109
 110 void
 111 regcache_invalidate_pid (int pid)
 112 {
 113   /* Only invalidate the regcaches of threads of this process.  */
 114   for_each_thread (pid, regcache_invalidate_thread);
 115 }
 116
 117 /* See regcache.h.  */
 118
 119 void
 120 regcache_invalidate (void)
 121 {
 122   /* Only update the threads of the current process.  */
 123   int pid = current_thread->id.pid ();
 124
 125   regcache_invalidate_pid (pid);
 126 }
 127
 128 #endif
 129
 130 struct regcache *
 131 init_register_cache (struct regcache *regcache,
 132                      const struct target_desc *tdesc,
 133                      unsigned char *regbuf)
 134 {
 135   if (regbuf == NULL)
 136     {
 137 #ifndef IN_PROCESS_AGENT
 138       /* Make sure to zero-initialize the register cache when it is
 139          created, in case there are registers the target never
 140          fetches.  This way they'll read as zero instead of
 141          garbage.  */
 142       regcache->tdesc = tdesc;
 143       regcache->registers
 144         = (unsigned char *) xcalloc (1, tdesc->registers_size);
 145       regcache->registers_owned = 1;
 146       regcache->register_status
 147         = (unsigned char *) xmalloc (tdesc->reg_defs.size ());
 148       memset ((void *) regcache->register_status, REG_UNAVAILABLE,
 149               tdesc->reg_defs.size ());
 150 #else
 151       gdb_assert_not_reached ("can't allocate memory from the heap");
 152 #endif
 153     }
 154   else
 155     {
 156       regcache->tdesc = tdesc;
 157       regcache->registers = regbuf;
 158       regcache->registers_owned = 0;
 159 #ifndef IN_PROCESS_AGENT
 160       regcache->register_status = NULL;
 161 #endif
 162     }
 163
 164   regcache->registers_valid = 0;
 165
 166   return regcache;
 167 }
 168
 169 #ifndef IN_PROCESS_AGENT
 170
 171 struct regcache *
 172 new_register_cache (const struct target_desc *tdesc)
 173 {
 174   struct regcache *regcache = new struct regcache;
 175
 176   gdb_assert (tdesc->registers_size != 0);
 177
 178   return init_register_cache (regcache, tdesc, NULL);
 179 }
 180
 181 void
 182 free_register_cache (struct regcache *regcache)
 183 {
 184   if (regcache)
 185     {
 186       if (regcache->registers_owned)
 187         free (regcache->registers);
 188       free (regcache->register_status);
 189       delete regcache;
 190     }
 191 }
 192
 193 #endif
 194
 195 void
 196 regcache_cpy (struct regcache *dst, struct regcache *src)
 197 {
 198   gdb_assert (src != NULL && dst != NULL);
 199   gdb_assert (src->tdesc == dst->tdesc);
 200   gdb_assert (src != dst);
 201
 202   memcpy (dst->registers, src->registers, src->tdesc->registers_size);
 203 #ifndef IN_PROCESS_AGENT
 204   if (dst->register_status != NULL && src->register_status != NULL)
 205     memcpy (dst->register_status, src->register_status,
 206             src->tdesc->reg_defs.size ());
 207 #endif
 208   dst->registers_valid = src->registers_valid;
 209 }
 210
 211 /* Return a reference to the description of register N.  */
 212
 213 static const struct reg &
 214 find_register_by_number (const struct target_desc *tdesc, int n)
 215 {
 216   return tdesc->reg_defs[n];
 217 }
 218
 219 #ifndef IN_PROCESS_AGENT
 220
 221 void
 222 registers_to_string (struct regcache *regcache, char *buf)
 223 {
 224   unsigned char *registers = regcache->registers;
 225   const struct target_desc *tdesc = regcache->tdesc;
 226
 227   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 228     {
 229       if (regcache->register_status[i] == REG_VALID)
 230         {
 231           bin2hex (registers, buf, register_size (tdesc, i));
 232           buf += register_size (tdesc, i) * 2;
 233         }
 234       else
 235         {
 236           memset (buf, 'x', register_size (tdesc, i) * 2);
 237           buf += register_size (tdesc, i) * 2;
 238         }
 239       registers += register_size (tdesc, i);
 240     }
 241   *buf = '\0';
 242 }
 243
 244 void
 245 registers_from_string (struct regcache *regcache, char *buf)
 246 {
 247   int len = strlen (buf);
 248   unsigned char *registers = regcache->registers;
 249   const struct target_desc *tdesc = regcache->tdesc;
 250
 251   if (len != tdesc->registers_size * 2)
 252     {
 253       warning ("Wrong sized register packet (expected %d bytes, got %d)",
 254                2 * tdesc->registers_size, len);
 255       if (len > tdesc->registers_size * 2)
 256         len = tdesc->registers_size * 2;
 257     }
 258   hex2bin (buf, registers, len / 2);
 259 }
 260
 261 int
 262 find_regno (const struct target_desc *tdesc, const char *name)
 263 {
 264   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 265     {
 266       if (strcmp (name, find_register_by_number (tdesc, i).name) == 0)
 267         return i;
 268     }
 269   internal_error (__FILE__, __LINE__, "Unknown register %s requested",
 270                   name);
 271 }
 272
 273 static void
 274 free_register_cache_thread (struct thread_info *thread)
 275 {
 276   struct regcache *regcache = thread_regcache_data (thread);
 277
 278   if (regcache != NULL)
 279     {
 280       regcache_invalidate_thread (thread);
 281       free_register_cache (regcache);
 282       set_thread_regcache_data (thread, NULL);
 283     }
 284 }
 285
 286 void
 287 regcache_release (void)
 288 {
 289   /* Flush and release all pre-existing register caches.  */
 290   for_each_thread (free_register_cache_thread);
 291 }
 292 #endif
 293
 294 int
 295 register_cache_size (const struct target_desc *tdesc)
 296 {
 297   return tdesc->registers_size;
 298 }
 299
 300 int
 301 register_size (const struct target_desc *tdesc, int n)
 302 {
 303   return find_register_by_number (tdesc, n).size / 8;
 304 }
 305
 306 /* See common/common-regcache.h.  */
 307
 308 int
 309 regcache_register_size (const struct regcache *regcache, int n)
 310 {
 311   return register_size (regcache->tdesc, n);
 312 }
 313
 314 static unsigned char *
 315 register_data (const struct regcache *regcache, int n, int fetch)
 316 {
 317   return (regcache->registers
 318           + find_register_by_number (regcache->tdesc, n).offset / 8);
 319 }
 320
 321 void
 322 supply_register (struct regcache *regcache, int n, const void *buf)
 323 {
 324   return regcache->raw_supply (n, buf);
 325 }
 326
 327 /* See common/common-regcache.h.  */
 328
 329 void
 330 regcache::raw_supply (int n, const void *buf)
 331 {
 332   if (buf)
 333     {
 334       memcpy (register_data (this, n, 0), buf, register_size (tdesc, n));
 335 #ifndef IN_PROCESS_AGENT
 336       if (register_status != NULL)
 337         register_status[n] = REG_VALID;
 338 #endif
 339     }
 340   else
 341     {
 342       memset (register_data (this, n, 0), 0, register_size (tdesc, n));
 343 #ifndef IN_PROCESS_AGENT
 344       if (register_status != NULL)
 345         register_status[n] = REG_UNAVAILABLE;
 346 #endif
 347     }
 348 }
 349
 350 /* Supply register N with value zero to REGCACHE.  */
 351
 352 void
 353 supply_register_zeroed (struct regcache *regcache, int n)
 354 {
 355   memset (register_data (regcache, n, 0), 0,
 356           register_size (regcache->tdesc, n));
 357 #ifndef IN_PROCESS_AGENT
 358   if (regcache->register_status != NULL)
 359     regcache->register_status[n] = REG_VALID;
 360 #endif
 361 }
 362
 363 #ifndef IN_PROCESS_AGENT
 364
 365 /* Supply register called NAME with value zero to REGCACHE.  */
 366
 367 void
 368 supply_register_by_name_zeroed (struct regcache *regcache,
 369                                 const char *name)
 370 {
 371   supply_register_zeroed (regcache, find_regno (regcache->tdesc, name));
 372 }
 373
 374 #endif
 375
 376 /* Supply the whole register set whose contents are stored in BUF, to
 377    REGCACHE.  If BUF is NULL, all the registers' values are recorded
 378    as unavailable.  */
 379
 380 void
 381 supply_regblock (struct regcache *regcache, const void *buf)
 382 {
 383   if (buf)
 384     {
 385       const struct target_desc *tdesc = regcache->tdesc;
 386
 387       memcpy (regcache->registers, buf, tdesc->registers_size);
 388 #ifndef IN_PROCESS_AGENT
 389       {
 390         int i;
 391
 392         for (i = 0; i < tdesc->reg_defs.size (); i++)
 393           regcache->register_status[i] = REG_VALID;
 394       }
 395 #endif
 396     }
 397   else
 398     {
 399       const struct target_desc *tdesc = regcache->tdesc;
 400
 401       memset (regcache->registers, 0, tdesc->registers_size);
 402 #ifndef IN_PROCESS_AGENT
 403       {
 404         int i;
 405
 406         for (i = 0; i < tdesc->reg_defs.size (); i++)
 407           regcache->register_status[i] = REG_UNAVAILABLE;
 408       }
 409 #endif
 410     }
 411 }
 412
 413 #ifndef IN_PROCESS_AGENT
 414
 415 void
 416 supply_register_by_name (struct regcache *regcache,
 417                          const char *name, const void *buf)
 418 {
 419   supply_register (regcache, find_regno (regcache->tdesc, name), buf);
 420 }
 421
 422 #endif
 423
 424 void
 425 collect_register (struct regcache *regcache, int n, void *buf)
 426 {
 427   regcache->raw_collect (n, buf);
 428 }
 429
 430 /* See common/common-regcache.h.  */
 431
 432 void
 433 regcache::raw_collect (int n, void *buf) const
 434 {
 435   memcpy (buf, register_data (this, n, 1), register_size (tdesc, n));
 436 }
 437
 438 enum register_status
 439 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 440                             ULONGEST *val)
 441 {
 442   int size;
 443
 444   gdb_assert (regcache != NULL);
 445   gdb_assert (regnum >= 0
 446               && regnum < regcache->tdesc->reg_defs.size ());
 447
 448   size = register_size (regcache->tdesc, regnum);
 449
 450   if (size > (int) sizeof (ULONGEST))
 451     error (_("That operation is not available on integers of more than"
 452             "%d bytes."),
 453           (int) sizeof (ULONGEST));
 454
 455   *val = 0;
 456   collect_register (regcache, regnum, val);
 457
 458   return REG_VALID;
 459 }
 460
 461 #ifndef IN_PROCESS_AGENT
 462
 463 /* See regcache.h.  */
 464
 465 ULONGEST
 466 regcache_raw_get_unsigned_by_name (struct regcache *regcache,
 467                                    const char *name)
 468 {
 469   return regcache_raw_get_unsigned (regcache,
 470                                     find_regno (regcache->tdesc, name));
 471 }
 472
 473 void
 474 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 475 {
 476   bin2hex (register_data (regcache, n, 1), buf,
 477            register_size (regcache->tdesc, n));
 478 }
 479
 480 void
 481 collect_register_by_name (struct regcache *regcache,
 482                           const char *name, void *buf)
 483 {
 484   collect_register (regcache, find_regno (regcache->tdesc, name), buf);
 485 }
 486
 487 /* Special handling for register PC.  */
 488
 489 CORE_ADDR
 490 regcache_read_pc (struct regcache *regcache)
 491 {
 492   CORE_ADDR pc_val;
 493
 494   if (the_target->read_pc)
 495     pc_val = the_target->read_pc (regcache);
 496   else
 497     internal_error (__FILE__, __LINE__,
 498                     "regcache_read_pc: Unable to find PC");
 499
 500   return pc_val;
 501 }
 502
 503 void
 504 regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 505 {
 506   if (the_target->write_pc)
 507     the_target->write_pc (regcache, pc);
 508   else
 509     internal_error (__FILE__, __LINE__,
 510                     "regcache_write_pc: Unable to update PC");
 511 }
 512
 513 #endif
 514
 515 /* See common/common-regcache.h.  */
 516
 517 enum register_status
 518 regcache::get_register_status (int regnum) const
 519 {
 520 #ifndef IN_PROCESS_AGENT
 521   gdb_assert (regnum >= 0 && regnum < tdesc->reg_defs.size ());
 522   return (enum register_status) (register_status[regnum]);
 523 #else
 524   return REG_VALID;
 525 #endif
 526 }
 527
 528 /* See common/common-regcache.h.  */
 529
 530 bool
 531 regcache::raw_compare (int regnum, const void *buf, int offset) const
 532 {
 533   gdb_assert (buf != NULL);
 534
 535   const unsigned char *regbuf = register_data (this, regnum, 1);
 536   int size = register_size (tdesc, regnum);
 537   gdb_assert (size >= offset);
 538
 539   return (memcmp (buf, regbuf + offset, size - offset) == 0);
 540 }