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   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 common/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 = XCNEW (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       free (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 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 common/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 (struct regcache *regcache, int n, int fetch)
 304 {
 305   return (regcache->registers
 306           + find_register_by_number (regcache->tdesc, n).offset / 8);
 307 }
 308
 309 /* Supply register N, whose contents are stored in BUF, to REGCACHE.
 310    If BUF is NULL, the register's value is recorded as
 311    unavailable.  */
 312
 313 void
 314 supply_register (struct regcache *regcache, int n, const void *buf)
 315 {
 316   if (buf)
 317     {
 318       memcpy (register_data (regcache, n, 0), buf,
 319               register_size (regcache->tdesc, n));
 320 #ifndef IN_PROCESS_AGENT
 321       if (regcache->register_status != NULL)
 322         regcache->register_status[n] = REG_VALID;
 323 #endif
 324     }
 325   else
 326     {
 327       memset (register_data (regcache, n, 0), 0,
 328               register_size (regcache->tdesc, n));
 329 #ifndef IN_PROCESS_AGENT
 330       if (regcache->register_status != NULL)
 331         regcache->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), 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   memcpy (buf, register_data (regcache, n, 1),
 414           register_size (regcache->tdesc, n));
 415 }
 416
 417 enum register_status
 418 regcache_raw_read_unsigned (struct regcache *regcache, int regnum,
 419                             ULONGEST *val)
 420 {
 421   int size;
 422
 423   gdb_assert (regcache != NULL);
 424   gdb_assert (regnum >= 0
 425               && regnum < regcache->tdesc->reg_defs.size ());
 426
 427   size = register_size (regcache->tdesc, regnum);
 428
 429   if (size > (int) sizeof (ULONGEST))
 430     error (_("That operation is not available on integers of more than"
 431             "%d bytes."),
 432           (int) sizeof (ULONGEST));
 433
 434   *val = 0;
 435   collect_register (regcache, regnum, val);
 436
 437   return REG_VALID;
 438 }
 439
 440 #ifndef IN_PROCESS_AGENT
 441
 442 void
 443 collect_register_as_string (struct regcache *regcache, int n, char *buf)
 444 {
 445   bin2hex (register_data (regcache, n, 1), buf,
 446            register_size (regcache->tdesc, n));
 447 }
 448
 449 void
 450 collect_register_by_name (struct regcache *regcache,
 451                           const char *name, void *buf)
 452 {
 453   collect_register (regcache, find_regno (regcache->tdesc, name), buf);
 454 }
 455
 456 /* Special handling for register PC.  */
 457
 458 CORE_ADDR
 459 regcache_read_pc (struct regcache *regcache)
 460 {
 461   CORE_ADDR pc_val;
 462
 463   if (the_target->read_pc)
 464     pc_val = the_target->read_pc (regcache);
 465   else
 466     internal_error (__FILE__, __LINE__,
 467                     "regcache_read_pc: Unable to find PC");
 468
 469   return pc_val;
 470 }
 471
 472 void
 473 regcache_write_pc (struct regcache *regcache, CORE_ADDR pc)
 474 {
 475   if (the_target->write_pc)
 476     the_target->write_pc (regcache, pc);
 477   else
 478     internal_error (__FILE__, __LINE__,
 479                     "regcache_write_pc: Unable to update PC");
 480 }
 481
 482 #endif