gdbserver/regcache.cc

   1 /* Register support routines for the remote server for GDB.
   2    Copyright (C) 2001-2021 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 "gdbsupport/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   regcache = thread_regcache_data (thread);
  32
  33   /* Threads' regcaches are created lazily, because biarch targets add
  34      the main thread/lwp before seeing it stop for the first time, and
  35      it is only after the target sees the thread stop for the first
  36      time that the target has a chance of determining the process's
  37      architecture.  IOW, when we first add the process's main thread
  38      we don't know which architecture/tdesc its regcache should
  39      have.  */
  40   if (regcache == NULL)
  41     {
  42       struct process_info *proc = get_thread_process (thread);
  43
  44       gdb_assert (proc->tdesc != NULL);
  45
  46       regcache = new_register_cache (proc->tdesc);
  47       set_thread_regcache_data (thread, regcache);
  48     }
  49
  50   if (fetch && regcache->registers_valid == 0)
  51     {
  52       struct thread_info *saved_thread = current_thread;
  53
  54       current_thread = thread;
  55       /* Invalidate all registers, to prevent stale left-overs.  */
  56       memset (regcache->register_status, REG_UNAVAILABLE,
  57               regcache->tdesc->reg_defs.size ());
  58       fetch_inferior_registers (regcache, -1);
  59       current_thread = saved_thread;
  60       regcache->registers_valid = 1;
  61     }
  62
  63   return regcache;
  64 }
  65
  66 /* See gdbsupport/common-regcache.h.  */
  67
  68 struct regcache *
  69 get_thread_regcache_for_ptid (ptid_t ptid)
  70 {
  71   return get_thread_regcache (find_thread_ptid (ptid), 1);
  72 }
  73
  74 void
  75 regcache_invalidate_thread (struct thread_info *thread)
  76 {
  77   struct regcache *regcache;
  78
  79   regcache = thread_regcache_data (thread);
  80
  81   if (regcache == NULL)
  82     return;
  83
  84   if (regcache->registers_valid)
  85     {
  86       struct thread_info *saved_thread = current_thread;
  87
  88       current_thread = thread;
  89       store_inferior_registers (regcache, -1);
  90       current_thread = saved_thread;
  91     }
  92
  93   regcache->registers_valid = 0;
  94 }
  95
  96 /* See regcache.h.  */
  97
  98 void
  99 regcache_invalidate_pid (int pid)
 100 {
 101   /* Only invalidate the regcaches of threads of this process.  */
 102   for_each_thread (pid, regcache_invalidate_thread);
 103 }
 104
 105 /* See regcache.h.  */
 106
 107 void
 108 regcache_invalidate (void)
 109 {
 110   /* Only update the threads of the current process.  */
 111   int pid = current_thread->id.pid ();
 112
 113   regcache_invalidate_pid (pid);
 114 }
 115
 116 #endif
 117
 118 struct regcache *
 119 init_register_cache (struct regcache *regcache,
 120                      const struct target_desc *tdesc,
 121                      unsigned char *regbuf)
 122 {
 123   if (regbuf == NULL)
 124     {
 125 #ifndef IN_PROCESS_AGENT
 126       /* Make sure to zero-initialize the register cache when it is
 127          created, in case there are registers the target never
 128          fetches.  This way they'll read as zero instead of
 129          garbage.  */
 130       regcache->tdesc = tdesc;
 131       regcache->registers
 132         = (unsigned char *) xcalloc (1, tdesc->registers_size);
 133       regcache->registers_owned = 1;
 134       regcache->register_status
 135         = (unsigned char *) xmalloc (tdesc->reg_defs.size ());
 136       memset ((void *) regcache->register_status, REG_UNAVAILABLE,
 137               tdesc->reg_defs.size ());
 138 #else
 139       gdb_assert_not_reached ("can't allocate memory from the heap");
 140 #endif
 141     }
 142   else
 143     {
 144       regcache->tdesc = tdesc;
 145       regcache->registers = regbuf;
 146       regcache->registers_owned = 0;
 147 #ifndef IN_PROCESS_AGENT
 148       regcache->register_status = NULL;
 149 #endif
 150     }
 151
 152   regcache->registers_valid = 0;
 153
 154   return regcache;
 155 }
 156
 157 #ifndef IN_PROCESS_AGENT
 158
 159 struct regcache *
 160 new_register_cache (const struct target_desc *tdesc)
 161 {
 162   struct regcache *regcache = new struct regcache;
 163
 164   gdb_assert (tdesc->registers_size != 0);
 165
 166   return init_register_cache (regcache, tdesc, NULL);
 167 }
 168
 169 void
 170 free_register_cache (struct regcache *regcache)
 171 {
 172   if (regcache)
 173     {
 174       if (regcache->registers_owned)
 175         free (regcache->registers);
 176       free (regcache->register_status);
 177       delete regcache;
 178     }
 179 }
 180
 181 #endif
 182
 183 void
 184 regcache_cpy (struct regcache *dst, struct regcache *src)
 185 {
 186   gdb_assert (src != NULL && dst != NULL);
 187   gdb_assert (src->tdesc == dst->tdesc);
 188   gdb_assert (src != dst);
 189
 190   memcpy (dst->registers, src->registers, src->tdesc->registers_size);
 191 #ifndef IN_PROCESS_AGENT
 192   if (dst->register_status != NULL && src->register_status != NULL)
 193     memcpy (dst->register_status, src->register_status,
 194             src->tdesc->reg_defs.size ());
 195 #endif
 196   dst->registers_valid = src->registers_valid;
 197 }
 198
 199 /* Return a reference to the description of register N.  */
 200
 201 static const struct gdb::reg &
 202 find_register_by_number (const struct target_desc *tdesc, int n)
 203 {
 204   return tdesc->reg_defs[n];
 205 }
 206
 207 #ifndef IN_PROCESS_AGENT
 208
 209 void
 210 registers_to_string (struct regcache *regcache, char *buf)
 211 {
 212   unsigned char *registers = regcache->registers;
 213   const struct target_desc *tdesc = regcache->tdesc;
 214
 215   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 216     {
 217       if (regcache->register_status[i] == REG_VALID)
 218         {
 219           bin2hex (registers, buf, register_size (tdesc, i));
 220           buf += register_size (tdesc, i) * 2;
 221         }
 222       else
 223         {
 224           memset (buf, 'x', register_size (tdesc, i) * 2);
 225           buf += register_size (tdesc, i) * 2;
 226         }
 227       registers += register_size (tdesc, i);
 228     }
 229   *buf = '\0';
 230 }
 231
 232 void
 233 registers_from_string (struct regcache *regcache, char *buf)
 234 {
 235   int len = strlen (buf);
 236   unsigned char *registers = regcache->registers;
 237   const struct target_desc *tdesc = regcache->tdesc;
 238
 239   if (len != tdesc->registers_size * 2)
 240     {
 241       warning ("Wrong sized register packet (expected %d bytes, got %d)",
 242                2 * tdesc->registers_size, len);
 243       if (len > tdesc->registers_size * 2)
 244         len = tdesc->registers_size * 2;
 245     }
 246   hex2bin (buf, registers, len / 2);
 247 }
 248
 249 int
 250 find_regno (const struct target_desc *tdesc, const char *name)
 251 {
 252   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 253     {
 254       if (strcmp (name, find_register_by_number (tdesc, i).name) == 0)
 255         return i;
 256     }
 257   internal_error (__FILE__, __LINE__, "Unknown register %s requested",
 258                   name);
 259 }
 260
 261 static void
 262 free_register_cache_thread (struct thread_info *thread)
 263 {
 264   struct regcache *regcache = thread_regcache_data (thread);
 265
 266   if (regcache != NULL)
 267     {
 268       regcache_invalidate_thread (thread);
 269       free_register_cache (regcache);
 270       set_thread_regcache_data (thread, NULL);
 271     }
 272 }
 273
 274 void
 275 regcache_release (void)
 276 {
 277   /* Flush and release all pre-existing register caches.  */
 278   for_each_thread (free_register_cache_thread);
 279 }
 280 #endif
 281
 282 int
 283 register_cache_size (const struct target_desc *tdesc)
 284 {
 285   return tdesc->registers_size;
 286 }
 287
 288 int
 289 register_size (const struct target_desc *tdesc, int n)
 290 {
 291   return find_register_by_number (tdesc, n).size / 8;
 292 }
 293
 294 /* See gdbsupport/common-regcache.h.  */
 295
 296 int
 297 regcache_register_size (const struct regcache *regcache, int n)
 298 {
 299   return register_size (regcache->tdesc, n);
 300 }
 301
 302 static unsigned char *
 303 register_data (const struct regcache *regcache, int n)
 304 {
 305   return (regcache->registers
 306           + find_register_by_number (regcache->tdesc, n).offset / 8);
 307 }
 308
 309 void
 310 supply_register (struct regcache *regcache, int n, const void *buf)
 311 {
 312   return regcache->raw_supply (n, buf);
 313 }
 314
 315 /* See gdbsupport/common-regcache.h.  */
 316
 317 void
 318 regcache::raw_supply (int n, const void *buf)
 319 {
 320   if (buf)
 321     {
 322       memcpy (register_data (this, n), buf, register_size (tdesc, n));
 323 #ifndef IN_PROCESS_AGENT
 324       if (register_status != NULL)
 325         register_status[n] = REG_VALID;
 326 #endif
 327     }
 328   else
 329     {
 330       memset (register_data (this, n), 0, register_size (tdesc, n));
 331 #ifndef IN_PROCESS_AGENT
 332       if (register_status != NULL)
 333         register_status[n] = REG_UNAVAILABLE;
 334 #endif
 335     }
 336 }
 337
 338 /* Supply register N with value zero to REGCACHE.  */
 339
 340 void
 341 supply_register_zeroed (struct regcache *regcache, int n)
 342 {
 343   memset (register_data (regcache, n), 0,
 344           register_size (regcache->tdesc, n));
 345 #ifndef IN_PROCESS_AGENT
 346   if (regcache->register_status != NULL)
 347     regcache->register_status[n] = REG_VALID;
 348 #endif
 349 }
 350
 351 #ifndef IN_PROCESS_AGENT
 352
 353 /* Supply register called NAME with value zero to REGCACHE.  */
 354
 355 void
 356 supply_register_by_name_zeroed (struct regcache *regcache,
 357                                 const char *name)
 358 {
 359   supply_register_zeroed (regcache, find_regno (regcache->tdesc, name));
 360 }
 361
 362 #endif
 363
 364 /* Supply the whole register set whose contents are stored in BUF, to
 365    REGCACHE.  If BUF is NULL, all the registers' values are recorded
 366    as unavailable.  */
 367
 368 void
 369 supply_regblock (struct regcache *regcache, const void *buf)
 370 {
 371   if (buf)
 372     {
 373       const struct target_desc *tdesc = regcache->tdesc;
 374
 375       memcpy (regcache->registers, buf, tdesc->registers_size);
 376 #ifndef IN_PROCESS_AGENT
 377       {
 378         int i;
 379
 380         for (i = 0; i < tdesc->reg_defs.size (); i++)
 381           regcache->register_status[i] = REG_VALID;
 382       }
 383 #endif
 384     }
 385   else
 386     {
 387       const struct target_desc *tdesc = regcache->tdesc;
 388
 389       memset (regcache->registers, 0, tdesc->registers_size);
 390 #ifndef IN_PROCESS_AGENT
 391       {
 392         int i;
 393
 394         for (i = 0; i < tdesc->reg_defs.size (); i++)
 395           regcache->register_status[i] = REG_UNAVAILABLE;
 396       }
 397 #endif
 398     }
 399 }
 400
 401 #ifndef IN_PROCESS_AGENT
 402
 403 void
 404 supply_register_by_name (struct regcache *regcache,
 405                          const char *name, const void *buf)
 406 {
 407   supply_register (regcache, find_regno (regcache->tdesc, name), buf);
 408 }
 409
 410 #endif
 411
 412 void
 413 collect_register (struct regcache *regcache, int n, void *buf)
 414 {
 415   regcache->raw_collect (n, buf);
 416 }
 417
 418 /* See gdbsupport/common-regcache.h.  */
 419
 420 void
 421 regcache::raw_collect (int n, void *buf) const
 422 {
 423   memcpy (buf, register_data (this, n), register_size (tdesc, n));
 424 }
 425
 426 enum register_status
 427 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 428                             ULONGEST *val)
 429 {
 430   int size;
 431
 432   gdb_assert (regcache != NULL);
 433   gdb_assert (regnum >= 0
 434               && regnum < regcache->tdesc->reg_defs.size ());
 435
 436   size = register_size (regcache->tdesc, regnum);
 437
 438   if (size > (int) sizeof (ULONGEST))
 439     error (_("That operation is not available on integers of more than"
 440             "%d bytes."),
 441           (int) sizeof (ULONGEST));
 442
 443   *val = 0;
 444   collect_register (regcache, regnum, val);
 445
 446   return REG_VALID;
 447 }
 448
 449 #ifndef IN_PROCESS_AGENT
 450
 451 /* See regcache.h.  */
 452
 453 ULONGEST
 454 regcache_raw_get_unsigned_by_name (struct regcache *regcache,
 455                                    const char *name)
 456 {
 457   return regcache_raw_get_unsigned (regcache,
 458                                     find_regno (regcache->tdesc, name));
 459 }
 460
 461 void
 462 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 463 {
 464   bin2hex (register_data (regcache, n), buf,
 465            register_size (regcache->tdesc, n));
 466 }
 467
 468 void
 469 collect_register_by_name (struct regcache *regcache,
 470                           const char *name, void *buf)
 471 {
 472   collect_register (regcache, find_regno (regcache->tdesc, name), buf);
 473 }
 474
 475 /* Special handling for register PC.  */
 476
 477 CORE_ADDR
 478 regcache_read_pc (struct regcache *regcache)
 479 {
 480   return the_target->read_pc (regcache);
 481 }
 482
 483 void
 484 regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 485 {
 486   the_target->write_pc (regcache, pc);
 487 }
 488
 489 #endif
 490
 491 /* See gdbsupport/common-regcache.h.  */
 492
 493 enum register_status
 494 regcache::get_register_status (int regnum) const
 495 {
 496 #ifndef IN_PROCESS_AGENT
 497   gdb_assert (regnum >= 0 && regnum < tdesc->reg_defs.size ());
 498   return (enum register_status) (register_status[regnum]);
 499 #else
 500   return REG_VALID;
 501 #endif
 502 }
 503
 504 /* See gdbsupport/common-regcache.h.  */
 505
 506 bool
 507 regcache::raw_compare (int regnum, const void *buf, int offset) const
 508 {
 509   gdb_assert (buf != NULL);
 510
 511   const unsigned char *regbuf = register_data (this, regnum);
 512   int size = register_size (tdesc, regnum);
 513   gdb_assert (size >= offset);
 514
 515   return (memcmp (buf, regbuf + offset, size - offset) == 0);
 516 }