gdbserver/regcache.cc

   1 /* Register support routines for the remote server for GDB.
   2    Copyright (C) 2001-2022 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       scoped_restore_current_thread restore_thread;
  53
  54       switch_to_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       regcache->registers_valid = 1;
  60     }
  61
  62   return regcache;
  63 }
  64
  65 /* See gdbsupport/common-regcache.h.  */
  66
  67 struct regcache *
  68 get_thread_regcache_for_ptid (ptid_t ptid)
  69 {
  70   return get_thread_regcache (find_thread_ptid (ptid), 1);
  71 }
  72
  73 void
  74 regcache_invalidate_thread (struct thread_info *thread)
  75 {
  76   struct regcache *regcache;
  77
  78   regcache = thread_regcache_data (thread);
  79
  80   if (regcache == NULL)
  81     return;
  82
  83   if (regcache->registers_valid)
  84     {
  85       scoped_restore_current_thread restore_thread;
  86
  87       switch_to_thread (thread);
  88       store_inferior_registers (regcache, -1);
  89     }
  90
  91   regcache->registers_valid = 0;
  92 }
  93
  94 /* See regcache.h.  */
  95
  96 void
  97 regcache_invalidate_pid (int pid)
  98 {
  99   /* Only invalidate the regcaches of threads of this process.  */
 100   for_each_thread (pid, regcache_invalidate_thread);
 101 }
 102
 103 /* See regcache.h.  */
 104
 105 void
 106 regcache_invalidate (void)
 107 {
 108   /* Only update the threads of the current process.  */
 109   int pid = current_thread->id.pid ();
 110
 111   regcache_invalidate_pid (pid);
 112 }
 113
 114 #endif
 115
 116 struct regcache *
 117 init_register_cache (struct regcache *regcache,
 118                      const struct target_desc *tdesc,
 119                      unsigned char *regbuf)
 120 {
 121   if (regbuf == NULL)
 122     {
 123 #ifndef IN_PROCESS_AGENT
 124       /* Make sure to zero-initialize the register cache when it is
 125          created, in case there are registers the target never
 126          fetches.  This way they'll read as zero instead of
 127          garbage.  */
 128       regcache->tdesc = tdesc;
 129       regcache->registers
 130         = (unsigned char *) xcalloc (1, tdesc->registers_size);
 131       regcache->registers_owned = 1;
 132       regcache->register_status
 133         = (unsigned char *) xmalloc (tdesc->reg_defs.size ());
 134       memset ((void *) regcache->register_status, REG_UNAVAILABLE,
 135               tdesc->reg_defs.size ());
 136 #else
 137       gdb_assert_not_reached ("can't allocate memory from the heap");
 138 #endif
 139     }
 140   else
 141     {
 142       regcache->tdesc = tdesc;
 143       regcache->registers = regbuf;
 144       regcache->registers_owned = 0;
 145 #ifndef IN_PROCESS_AGENT
 146       regcache->register_status = NULL;
 147 #endif
 148     }
 149
 150   regcache->registers_valid = 0;
 151
 152   return regcache;
 153 }
 154
 155 #ifndef IN_PROCESS_AGENT
 156
 157 struct regcache *
 158 new_register_cache (const struct target_desc *tdesc)
 159 {
 160   struct regcache *regcache = new struct regcache;
 161
 162   gdb_assert (tdesc->registers_size != 0);
 163
 164   return init_register_cache (regcache, tdesc, NULL);
 165 }
 166
 167 void
 168 free_register_cache (struct regcache *regcache)
 169 {
 170   if (regcache)
 171     {
 172       if (regcache->registers_owned)
 173         free (regcache->registers);
 174       free (regcache->register_status);
 175       delete regcache;
 176     }
 177 }
 178
 179 #endif
 180
 181 void
 182 regcache_cpy (struct regcache *dst, struct regcache *src)
 183 {
 184   gdb_assert (src != NULL && dst != NULL);
 185   gdb_assert (src->tdesc == dst->tdesc);
 186   gdb_assert (src != dst);
 187
 188   memcpy (dst->registers, src->registers, src->tdesc->registers_size);
 189 #ifndef IN_PROCESS_AGENT
 190   if (dst->register_status != NULL && src->register_status != NULL)
 191     memcpy (dst->register_status, src->register_status,
 192             src->tdesc->reg_defs.size ());
 193 #endif
 194   dst->registers_valid = src->registers_valid;
 195 }
 196
 197 /* Return a reference to the description of register N.  */
 198
 199 static const struct gdb::reg &
 200 find_register_by_number (const struct target_desc *tdesc, int n)
 201 {
 202   return tdesc->reg_defs[n];
 203 }
 204
 205 #ifndef IN_PROCESS_AGENT
 206
 207 void
 208 registers_to_string (struct regcache *regcache, char *buf)
 209 {
 210   unsigned char *registers = regcache->registers;
 211   const struct target_desc *tdesc = regcache->tdesc;
 212
 213   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 214     {
 215       if (regcache->register_status[i] == REG_VALID)
 216         {
 217           bin2hex (registers, buf, register_size (tdesc, i));
 218           buf += register_size (tdesc, i) * 2;
 219         }
 220       else
 221         {
 222           memset (buf, 'x', register_size (tdesc, i) * 2);
 223           buf += register_size (tdesc, i) * 2;
 224         }
 225       registers += register_size (tdesc, i);
 226     }
 227   *buf = '\0';
 228 }
 229
 230 void
 231 registers_from_string (struct regcache *regcache, char *buf)
 232 {
 233   int len = strlen (buf);
 234   unsigned char *registers = regcache->registers;
 235   const struct target_desc *tdesc = regcache->tdesc;
 236
 237   if (len != tdesc->registers_size * 2)
 238     {
 239       warning ("Wrong sized register packet (expected %d bytes, got %d)",
 240                2 * tdesc->registers_size, len);
 241       if (len > tdesc->registers_size * 2)
 242         len = tdesc->registers_size * 2;
 243     }
 244   hex2bin (buf, registers, len / 2);
 245 }
 246
 247 int
 248 find_regno (const struct target_desc *tdesc, const char *name)
 249 {
 250   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 251     {
 252       if (strcmp (name, find_register_by_number (tdesc, i).name) == 0)
 253         return i;
 254     }
 255   internal_error ("Unknown register %s requested",
 256                   name);
 257 }
 258
 259 static void
 260 free_register_cache_thread (struct thread_info *thread)
 261 {
 262   struct regcache *regcache = thread_regcache_data (thread);
 263
 264   if (regcache != NULL)
 265     {
 266       regcache_invalidate_thread (thread);
 267       free_register_cache (regcache);
 268       set_thread_regcache_data (thread, NULL);
 269     }
 270 }
 271
 272 void
 273 regcache_release (void)
 274 {
 275   /* Flush and release all pre-existing register caches.  */
 276   for_each_thread (free_register_cache_thread);
 277 }
 278 #endif
 279
 280 int
 281 register_cache_size (const struct target_desc *tdesc)
 282 {
 283   return tdesc->registers_size;
 284 }
 285
 286 int
 287 register_size (const struct target_desc *tdesc, int n)
 288 {
 289   return find_register_by_number (tdesc, n).size / 8;
 290 }
 291
 292 /* See gdbsupport/common-regcache.h.  */
 293
 294 int
 295 regcache_register_size (const struct regcache *regcache, int n)
 296 {
 297   return register_size (regcache->tdesc, n);
 298 }
 299
 300 static unsigned char *
 301 register_data (const struct regcache *regcache, int n)
 302 {
 303   return (regcache->registers
 304           + find_register_by_number (regcache->tdesc, n).offset / 8);
 305 }
 306
 307 void
 308 supply_register (struct regcache *regcache, int n, const void *buf)
 309 {
 310   return regcache->raw_supply (n, buf);
 311 }
 312
 313 /* See gdbsupport/common-regcache.h.  */
 314
 315 void
 316 regcache::raw_supply (int n, const void *buf)
 317 {
 318   if (buf)
 319     {
 320       memcpy (register_data (this, n), buf, register_size (tdesc, n));
 321 #ifndef IN_PROCESS_AGENT
 322       if (register_status != NULL)
 323         register_status[n] = REG_VALID;
 324 #endif
 325     }
 326   else
 327     {
 328       memset (register_data (this, n), 0, register_size (tdesc, n));
 329 #ifndef IN_PROCESS_AGENT
 330       if (register_status != NULL)
 331         register_status[n] = REG_UNAVAILABLE;
 332 #endif
 333     }
 334 }
 335
 336 /* Supply register N with value zero to REGCACHE.  */
 337
 338 void
 339 supply_register_zeroed (struct regcache *regcache, int n)
 340 {
 341   memset (register_data (regcache, n), 0,
 342           register_size (regcache->tdesc, n));
 343 #ifndef IN_PROCESS_AGENT
 344   if (regcache->register_status != NULL)
 345     regcache->register_status[n] = REG_VALID;
 346 #endif
 347 }
 348
 349 #ifndef IN_PROCESS_AGENT
 350
 351 /* Supply register called NAME with value zero to REGCACHE.  */
 352
 353 void
 354 supply_register_by_name_zeroed (struct regcache *regcache,
 355                                 const char *name)
 356 {
 357   supply_register_zeroed (regcache, find_regno (regcache->tdesc, name));
 358 }
 359
 360 #endif
 361
 362 /* Supply the whole register set whose contents are stored in BUF, to
 363    REGCACHE.  If BUF is NULL, all the registers' values are recorded
 364    as unavailable.  */
 365
 366 void
 367 supply_regblock (struct regcache *regcache, const void *buf)
 368 {
 369   if (buf)
 370     {
 371       const struct target_desc *tdesc = regcache->tdesc;
 372
 373       memcpy (regcache->registers, buf, tdesc->registers_size);
 374 #ifndef IN_PROCESS_AGENT
 375       {
 376         int i;
 377
 378         for (i = 0; i < tdesc->reg_defs.size (); i++)
 379           regcache->register_status[i] = REG_VALID;
 380       }
 381 #endif
 382     }
 383   else
 384     {
 385       const struct target_desc *tdesc = regcache->tdesc;
 386
 387       memset (regcache->registers, 0, 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_UNAVAILABLE;
 394       }
 395 #endif
 396     }
 397 }
 398
 399 #ifndef IN_PROCESS_AGENT
 400
 401 void
 402 supply_register_by_name (struct regcache *regcache,
 403                          const char *name, const void *buf)
 404 {
 405   supply_register (regcache, find_regno (regcache->tdesc, name), buf);
 406 }
 407
 408 #endif
 409
 410 void
 411 collect_register (struct regcache *regcache, int n, void *buf)
 412 {
 413   regcache->raw_collect (n, buf);
 414 }
 415
 416 /* See gdbsupport/common-regcache.h.  */
 417
 418 void
 419 regcache::raw_collect (int n, void *buf) const
 420 {
 421   memcpy (buf, register_data (this, n), register_size (tdesc, n));
 422 }
 423
 424 enum register_status
 425 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 426                             ULONGEST *val)
 427 {
 428   int size;
 429
 430   gdb_assert (regcache != NULL);
 431   gdb_assert (regnum >= 0
 432               && regnum < regcache->tdesc->reg_defs.size ());
 433
 434   size = register_size (regcache->tdesc, regnum);
 435
 436   if (size > (int) sizeof (ULONGEST))
 437     error (_("That operation is not available on integers of more than"
 438             "%d bytes."),
 439           (int) sizeof (ULONGEST));
 440
 441   *val = 0;
 442   collect_register (regcache, regnum, val);
 443
 444   return REG_VALID;
 445 }
 446
 447 #ifndef IN_PROCESS_AGENT
 448
 449 /* See regcache.h.  */
 450
 451 ULONGEST
 452 regcache_raw_get_unsigned_by_name (struct regcache *regcache,
 453                                    const char *name)
 454 {
 455   return regcache_raw_get_unsigned (regcache,
 456                                     find_regno (regcache->tdesc, name));
 457 }
 458
 459 void
 460 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 461 {
 462   bin2hex (register_data (regcache, n), buf,
 463            register_size (regcache->tdesc, n));
 464 }
 465
 466 void
 467 collect_register_by_name (struct regcache *regcache,
 468                           const char *name, void *buf)
 469 {
 470   collect_register (regcache, find_regno (regcache->tdesc, name), buf);
 471 }
 472
 473 /* Special handling for register PC.  */
 474
 475 CORE_ADDR
 476 regcache_read_pc (struct regcache *regcache)
 477 {
 478   return the_target->read_pc (regcache);
 479 }
 480
 481 void
 482 regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 483 {
 484   the_target->write_pc (regcache, pc);
 485 }
 486
 487 #endif
 488
 489 /* See gdbsupport/common-regcache.h.  */
 490
 491 enum register_status
 492 regcache::get_register_status (int regnum) const
 493 {
 494 #ifndef IN_PROCESS_AGENT
 495   gdb_assert (regnum >= 0 && regnum < tdesc->reg_defs.size ());
 496   return (enum register_status) (register_status[regnum]);
 497 #else
 498   return REG_VALID;
 499 #endif
 500 }
 501
 502 /* See gdbsupport/common-regcache.h.  */
 503
 504 bool
 505 regcache::raw_compare (int regnum, const void *buf, int offset) const
 506 {
 507   gdb_assert (buf != NULL);
 508
 509   const unsigned char *regbuf = register_data (this, regnum);
 510   int size = register_size (tdesc, regnum);
 511   gdb_assert (size >= offset);
 512
 513   return (memcmp (buf, regbuf + offset, size - offset) == 0);
 514 }