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 /* See regcache.h */
 248
 249 gdb::optional<int>
 250 find_regno_no_throw (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   return {};
 258 }
 259
 260 int
 261 find_regno (const struct target_desc *tdesc, const char *name)
 262 {
 263   gdb::optional<int> regnum = find_regno_no_throw (tdesc, name);
 264
 265   if (regnum.has_value ())
 266     return *regnum;
 267
 268   internal_error ("Unknown register %s requested", name);
 269 }
 270
 271 static void
 272 free_register_cache_thread (struct thread_info *thread)
 273 {
 274   struct regcache *regcache = thread_regcache_data (thread);
 275
 276   if (regcache != NULL)
 277     {
 278       regcache_invalidate_thread (thread);
 279       free_register_cache (regcache);
 280       set_thread_regcache_data (thread, NULL);
 281     }
 282 }
 283
 284 void
 285 regcache_release (void)
 286 {
 287   /* Flush and release all pre-existing register caches.  */
 288   for_each_thread (free_register_cache_thread);
 289 }
 290 #endif
 291
 292 int
 293 register_cache_size (const struct target_desc *tdesc)
 294 {
 295   return tdesc->registers_size;
 296 }
 297
 298 int
 299 register_size (const struct target_desc *tdesc, int n)
 300 {
 301   return find_register_by_number (tdesc, n).size / 8;
 302 }
 303
 304 /* See gdbsupport/common-regcache.h.  */
 305
 306 int
 307 regcache_register_size (const struct regcache *regcache, int n)
 308 {
 309   return register_size (regcache->tdesc, n);
 310 }
 311
 312 static unsigned char *
 313 register_data (const struct regcache *regcache, int n)
 314 {
 315   return (regcache->registers
 316           + find_register_by_number (regcache->tdesc, n).offset / 8);
 317 }
 318
 319 void
 320 supply_register (struct regcache *regcache, int n, const void *buf)
 321 {
 322   return regcache->raw_supply (n, buf);
 323 }
 324
 325 /* See gdbsupport/common-regcache.h.  */
 326
 327 void
 328 regcache::raw_supply (int n, const void *buf)
 329 {
 330   if (buf)
 331     {
 332       memcpy (register_data (this, n), buf, register_size (tdesc, n));
 333 #ifndef IN_PROCESS_AGENT
 334       if (register_status != NULL)
 335         register_status[n] = REG_VALID;
 336 #endif
 337     }
 338   else
 339     {
 340       memset (register_data (this, n), 0, register_size (tdesc, n));
 341 #ifndef IN_PROCESS_AGENT
 342       if (register_status != NULL)
 343         register_status[n] = REG_UNAVAILABLE;
 344 #endif
 345     }
 346 }
 347
 348 /* Supply register N with value zero to REGCACHE.  */
 349
 350 void
 351 supply_register_zeroed (struct regcache *regcache, int n)
 352 {
 353   memset (register_data (regcache, n), 0,
 354           register_size (regcache->tdesc, n));
 355 #ifndef IN_PROCESS_AGENT
 356   if (regcache->register_status != NULL)
 357     regcache->register_status[n] = REG_VALID;
 358 #endif
 359 }
 360
 361 #ifndef IN_PROCESS_AGENT
 362
 363 /* Supply register called NAME with value zero to REGCACHE.  */
 364
 365 void
 366 supply_register_by_name_zeroed (struct regcache *regcache,
 367                                 const char *name)
 368 {
 369   supply_register_zeroed (regcache, find_regno (regcache->tdesc, name));
 370 }
 371
 372 #endif
 373
 374 /* Supply the whole register set whose contents are stored in BUF, to
 375    REGCACHE.  If BUF is NULL, all the registers' values are recorded
 376    as unavailable.  */
 377
 378 void
 379 supply_regblock (struct regcache *regcache, const void *buf)
 380 {
 381   if (buf)
 382     {
 383       const struct target_desc *tdesc = regcache->tdesc;
 384
 385       memcpy (regcache->registers, buf, tdesc->registers_size);
 386 #ifndef IN_PROCESS_AGENT
 387       {
 388         int i;
 389
 390         for (i = 0; i < tdesc->reg_defs.size (); i++)
 391           regcache->register_status[i] = REG_VALID;
 392       }
 393 #endif
 394     }
 395   else
 396     {
 397       const struct target_desc *tdesc = regcache->tdesc;
 398
 399       memset (regcache->registers, 0, tdesc->registers_size);
 400 #ifndef IN_PROCESS_AGENT
 401       {
 402         int i;
 403
 404         for (i = 0; i < tdesc->reg_defs.size (); i++)
 405           regcache->register_status[i] = REG_UNAVAILABLE;
 406       }
 407 #endif
 408     }
 409 }
 410
 411 #ifndef IN_PROCESS_AGENT
 412
 413 void
 414 supply_register_by_name (struct regcache *regcache,
 415                          const char *name, const void *buf)
 416 {
 417   supply_register (regcache, find_regno (regcache->tdesc, name), buf);
 418 }
 419
 420 #endif
 421
 422 void
 423 collect_register (struct regcache *regcache, int n, void *buf)
 424 {
 425   regcache->raw_collect (n, buf);
 426 }
 427
 428 /* See gdbsupport/common-regcache.h.  */
 429
 430 void
 431 regcache::raw_collect (int n, void *buf) const
 432 {
 433   memcpy (buf, register_data (this, n), register_size (tdesc, n));
 434 }
 435
 436 enum register_status
 437 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 438                             ULONGEST *val)
 439 {
 440   int size;
 441
 442   gdb_assert (regcache != NULL);
 443   gdb_assert (regnum >= 0
 444               && regnum < regcache->tdesc->reg_defs.size ());
 445
 446   size = register_size (regcache->tdesc, regnum);
 447
 448   if (size > (int) sizeof (ULONGEST))
 449     error (_("That operation is not available on integers of more than"
 450             "%d bytes."),
 451           (int) sizeof (ULONGEST));
 452
 453   *val = 0;
 454   collect_register (regcache, regnum, val);
 455
 456   return REG_VALID;
 457 }
 458
 459 #ifndef IN_PROCESS_AGENT
 460
 461 /* See regcache.h.  */
 462
 463 ULONGEST
 464 regcache_raw_get_unsigned_by_name (struct regcache *regcache,
 465                                    const char *name)
 466 {
 467   return regcache_raw_get_unsigned (regcache,
 468                                     find_regno (regcache->tdesc, name));
 469 }
 470
 471 void
 472 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 473 {
 474   bin2hex (register_data (regcache, n), buf,
 475            register_size (regcache->tdesc, n));
 476 }
 477
 478 void
 479 collect_register_by_name (struct regcache *regcache,
 480                           const char *name, void *buf)
 481 {
 482   collect_register (regcache, find_regno (regcache->tdesc, name), buf);
 483 }
 484
 485 /* Special handling for register PC.  */
 486
 487 CORE_ADDR
 488 regcache_read_pc (struct regcache *regcache)
 489 {
 490   return the_target->read_pc (regcache);
 491 }
 492
 493 void
 494 regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 495 {
 496   the_target->write_pc (regcache, pc);
 497 }
 498
 499 #endif
 500
 501 /* See gdbsupport/common-regcache.h.  */
 502
 503 enum register_status
 504 regcache::get_register_status (int regnum) const
 505 {
 506 #ifndef IN_PROCESS_AGENT
 507   gdb_assert (regnum >= 0 && regnum < tdesc->reg_defs.size ());
 508   return (enum register_status) (register_status[regnum]);
 509 #else
 510   return REG_VALID;
 511 #endif
 512 }
 513
 514 /* See gdbsupport/common-regcache.h.  */
 515
 516 bool
 517 regcache::raw_compare (int regnum, const void *buf, int offset) const
 518 {
 519   gdb_assert (buf != NULL);
 520
 521   const unsigned char *regbuf = register_data (this, regnum);
 522   int size = register_size (tdesc, regnum);
 523   gdb_assert (size >= offset);
 524
 525   return (memcmp (buf, regbuf + offset, size - offset) == 0);
 526 }