gdbserver/regcache.cc

   1 /* Register support routines for the remote server for GDB.
   2    Copyright (C) 2001-2023 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   gdb_assert (n >= 0);
 203   gdb_assert (n < tdesc->reg_defs.size ());
 204
 205   return tdesc->reg_defs[n];
 206 }
 207
 208 #ifndef IN_PROCESS_AGENT
 209
 210 void
 211 registers_to_string (struct regcache *regcache, char *buf)
 212 {
 213   unsigned char *registers = regcache->registers;
 214   const struct target_desc *tdesc = regcache->tdesc;
 215
 216   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 217     {
 218       if (regcache->register_status[i] == REG_VALID)
 219         {
 220           bin2hex (registers, buf, register_size (tdesc, i));
 221           buf += register_size (tdesc, i) * 2;
 222         }
 223       else
 224         {
 225           memset (buf, 'x', register_size (tdesc, i) * 2);
 226           buf += register_size (tdesc, i) * 2;
 227         }
 228       registers += register_size (tdesc, i);
 229     }
 230   *buf = '\0';
 231 }
 232
 233 void
 234 registers_from_string (struct regcache *regcache, char *buf)
 235 {
 236   int len = strlen (buf);
 237   unsigned char *registers = regcache->registers;
 238   const struct target_desc *tdesc = regcache->tdesc;
 239
 240   if (len != tdesc->registers_size * 2)
 241     {
 242       warning ("Wrong sized register packet (expected %d bytes, got %d)",
 243                2 * tdesc->registers_size, len);
 244       if (len > tdesc->registers_size * 2)
 245         len = tdesc->registers_size * 2;
 246     }
 247   hex2bin (buf, registers, len / 2);
 248 }
 249
 250 /* See regcache.h */
 251
 252 gdb::optional<int>
 253 find_regno_no_throw (const struct target_desc *tdesc, const char *name)
 254 {
 255   for (int i = 0; i < tdesc->reg_defs.size (); ++i)
 256     {
 257       if (strcmp (name, find_register_by_number (tdesc, i).name) == 0)
 258         return i;
 259     }
 260   return {};
 261 }
 262
 263 int
 264 find_regno (const struct target_desc *tdesc, const char *name)
 265 {
 266   gdb::optional<int> regnum = find_regno_no_throw (tdesc, name);
 267
 268   if (regnum.has_value ())
 269     return *regnum;
 270
 271   internal_error ("Unknown register %s requested", name);
 272 }
 273
 274 static void
 275 free_register_cache_thread (struct thread_info *thread)
 276 {
 277   struct regcache *regcache = thread_regcache_data (thread);
 278
 279   if (regcache != NULL)
 280     {
 281       regcache_invalidate_thread (thread);
 282       free_register_cache (regcache);
 283       set_thread_regcache_data (thread, NULL);
 284     }
 285 }
 286
 287 void
 288 regcache_release (void)
 289 {
 290   /* Flush and release all pre-existing register caches.  */
 291   for_each_thread (free_register_cache_thread);
 292 }
 293 #endif
 294
 295 int
 296 register_cache_size (const struct target_desc *tdesc)
 297 {
 298   return tdesc->registers_size;
 299 }
 300
 301 int
 302 register_size (const struct target_desc *tdesc, int n)
 303 {
 304   return find_register_by_number (tdesc, n).size / 8;
 305 }
 306
 307 /* See gdbsupport/common-regcache.h.  */
 308
 309 int
 310 regcache_register_size (const struct regcache *regcache, int n)
 311 {
 312   return register_size (regcache->tdesc, n);
 313 }
 314
 315 static unsigned char *
 316 register_data (const struct regcache *regcache, int n)
 317 {
 318   return (regcache->registers
 319           + find_register_by_number (regcache->tdesc, n).offset / 8);
 320 }
 321
 322 void
 323 supply_register (struct regcache *regcache, int n, const void *buf)
 324 {
 325   return regcache->raw_supply (n, buf);
 326 }
 327
 328 /* See gdbsupport/common-regcache.h.  */
 329
 330 void
 331 regcache::raw_supply (int n, const void *buf)
 332 {
 333   if (buf)
 334     {
 335       memcpy (register_data (this, n), buf, register_size (tdesc, n));
 336 #ifndef IN_PROCESS_AGENT
 337       if (register_status != NULL)
 338         register_status[n] = REG_VALID;
 339 #endif
 340     }
 341   else
 342     {
 343       memset (register_data (this, n), 0, register_size (tdesc, n));
 344 #ifndef IN_PROCESS_AGENT
 345       if (register_status != NULL)
 346         register_status[n] = REG_UNAVAILABLE;
 347 #endif
 348     }
 349 }
 350
 351 /* Supply register N with value zero to REGCACHE.  */
 352
 353 void
 354 supply_register_zeroed (struct regcache *regcache, int n)
 355 {
 356   memset (register_data (regcache, n), 0,
 357           register_size (regcache->tdesc, n));
 358 #ifndef IN_PROCESS_AGENT
 359   if (regcache->register_status != NULL)
 360     regcache->register_status[n] = REG_VALID;
 361 #endif
 362 }
 363
 364 #ifndef IN_PROCESS_AGENT
 365
 366 /* Supply register called NAME with value zero to REGCACHE.  */
 367
 368 void
 369 supply_register_by_name_zeroed (struct regcache *regcache,
 370                                 const char *name)
 371 {
 372   supply_register_zeroed (regcache, find_regno (regcache->tdesc, name));
 373 }
 374
 375 #endif
 376
 377 /* Supply the whole register set whose contents are stored in BUF, to
 378    REGCACHE.  If BUF is NULL, all the registers' values are recorded
 379    as unavailable.  */
 380
 381 void
 382 supply_regblock (struct regcache *regcache, const void *buf)
 383 {
 384   if (buf)
 385     {
 386       const struct target_desc *tdesc = regcache->tdesc;
 387
 388       memcpy (regcache->registers, buf, tdesc->registers_size);
 389 #ifndef IN_PROCESS_AGENT
 390       {
 391         int i;
 392
 393         for (i = 0; i < tdesc->reg_defs.size (); i++)
 394           regcache->register_status[i] = REG_VALID;
 395       }
 396 #endif
 397     }
 398   else
 399     {
 400       const struct target_desc *tdesc = regcache->tdesc;
 401
 402       memset (regcache->registers, 0, tdesc->registers_size);
 403 #ifndef IN_PROCESS_AGENT
 404       {
 405         int i;
 406
 407         for (i = 0; i < tdesc->reg_defs.size (); i++)
 408           regcache->register_status[i] = REG_UNAVAILABLE;
 409       }
 410 #endif
 411     }
 412 }
 413
 414 #ifndef IN_PROCESS_AGENT
 415
 416 void
 417 supply_register_by_name (struct regcache *regcache,
 418                          const char *name, const void *buf)
 419 {
 420   supply_register (regcache, find_regno (regcache->tdesc, name), buf);
 421 }
 422
 423 #endif
 424
 425 void
 426 collect_register (struct regcache *regcache, int n, void *buf)
 427 {
 428   regcache->raw_collect (n, buf);
 429 }
 430
 431 /* See gdbsupport/common-regcache.h.  */
 432
 433 void
 434 regcache::raw_collect (int n, void *buf) const
 435 {
 436   memcpy (buf, register_data (this, n), register_size (tdesc, n));
 437 }
 438
 439 enum register_status
 440 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 441                             ULONGEST *val)
 442 {
 443   int size;
 444
 445   gdb_assert (regcache != NULL);
 446
 447   size = register_size (regcache->tdesc, regnum);
 448
 449   if (size > (int) sizeof (ULONGEST))
 450     error (_("That operation is not available on integers of more than"
 451             "%d bytes."),
 452           (int) sizeof (ULONGEST));
 453
 454   *val = 0;
 455   collect_register (regcache, regnum, val);
 456
 457   return REG_VALID;
 458 }
 459
 460 #ifndef IN_PROCESS_AGENT
 461
 462 /* See regcache.h.  */
 463
 464 ULONGEST
 465 regcache_raw_get_unsigned_by_name (struct regcache *regcache,
 466                                    const char *name)
 467 {
 468   return regcache_raw_get_unsigned (regcache,
 469                                     find_regno (regcache->tdesc, name));
 470 }
 471
 472 void
 473 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 474 {
 475   bin2hex (register_data (regcache, n), buf,
 476            register_size (regcache->tdesc, n));
 477 }
 478
 479 void
 480 collect_register_by_name (struct regcache *regcache,
 481                           const char *name, void *buf)
 482 {
 483   collect_register (regcache, find_regno (regcache->tdesc, name), buf);
 484 }
 485
 486 /* Special handling for register PC.  */
 487
 488 CORE_ADDR
 489 regcache_read_pc (struct regcache *regcache)
 490 {
 491   return the_target->read_pc (regcache);
 492 }
 493
 494 void
 495 regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 496 {
 497   the_target->write_pc (regcache, pc);
 498 }
 499
 500 #endif
 501
 502 /* See gdbsupport/common-regcache.h.  */
 503
 504 enum register_status
 505 regcache::get_register_status (int regnum) const
 506 {
 507 #ifndef IN_PROCESS_AGENT
 508   gdb_assert (regnum >= 0 && regnum < tdesc->reg_defs.size ());
 509   return (enum register_status) (register_status[regnum]);
 510 #else
 511   return REG_VALID;
 512 #endif
 513 }
 514
 515 /* See gdbsupport/common-regcache.h.  */
 516
 517 bool
 518 regcache::raw_compare (int regnum, const void *buf, int offset) const
 519 {
 520   gdb_assert (buf != NULL);
 521
 522   const unsigned char *regbuf = register_data (this, regnum);
 523   int size = register_size (tdesc, regnum);
 524   gdb_assert (size >= offset);
 525
 526   return (memcmp (buf, regbuf + offset, size - offset) == 0);
 527 }