gdb/dcache.c

   1 /* Caching code for GDB, the GNU debugger.
   2
   3    Copyright (C) 1992-1993, 1995-1996, 1998-2001, 2003, 2007-2012 Free
   4    Software Foundation, Inc.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  20
  21 #include "defs.h"
  22 #include "dcache.h"
  23 #include "gdbcmd.h"
  24 #include "gdb_string.h"
  25 #include "gdbcore.h"
  26 #include "target.h"
  27 #include "inferior.h"
  28 #include "splay-tree.h"
  29
  30 /* Commands with a prefix of `{set,show} dcache'.  */
  31 static struct cmd_list_element *dcache_set_list = NULL;
  32 static struct cmd_list_element *dcache_show_list = NULL;
  33
  34 /* The data cache could lead to incorrect results because it doesn't
  35    know about volatile variables, thus making it impossible to debug
  36    functions which use memory mapped I/O devices.  Set the nocache
  37    memory region attribute in those cases.
  38
  39    In general the dcache speeds up performance.  Some speed improvement
  40    comes from the actual caching mechanism, but the major gain is in
  41    the reduction of the remote protocol overhead; instead of reading
  42    or writing a large area of memory in 4 byte requests, the cache
  43    bundles up the requests into LINE_SIZE chunks, reducing overhead
  44    significantly.  This is most useful when accessing a large amount
  45    of data, such as when performing a backtrace.
  46
  47    The cache is a splay tree along with a linked list for replacement.
  48    Each block caches a LINE_SIZE area of memory.  Within each line we
  49    remember the address of the line (which must be a multiple of
  50    LINE_SIZE) and the actual data block.
  51
  52    Lines are only allocated as needed, so DCACHE_SIZE really specifies the
  53    *maximum* number of lines in the cache.
  54
  55    At present, the cache is write-through rather than writeback: as soon
  56    as data is written to the cache, it is also immediately written to
  57    the target.  Therefore, cache lines are never "dirty".  Whether a given
  58    line is valid or not depends on where it is stored in the dcache_struct;
  59    there is no per-block valid flag.  */
  60
  61 /* NOTE: Interaction of dcache and memory region attributes
  62
  63    As there is no requirement that memory region attributes be aligned
  64    to or be a multiple of the dcache page size, dcache_read_line() and
  65    dcache_write_line() must break up the page by memory region.  If a
  66    chunk does not have the cache attribute set, an invalid memory type
  67    is set, etc., then the chunk is skipped.  Those chunks are handled
  68    in target_xfer_memory() (or target_xfer_memory_partial()).
  69
  70    This doesn't occur very often.  The most common occurance is when
  71    the last bit of the .text segment and the first bit of the .data
  72    segment fall within the same dcache page with a ro/cacheable memory
  73    region defined for the .text segment and a rw/non-cacheable memory
  74    region defined for the .data segment.  */
  75
  76 /* The maximum number of lines stored.  The total size of the cache is
  77    equal to DCACHE_SIZE times LINE_SIZE.  */
  78 #define DCACHE_DEFAULT_SIZE 4096
  79 static unsigned dcache_size = DCACHE_DEFAULT_SIZE;
  80
  81 /* The default size of a cache line.  Smaller values reduce the time taken to
  82    read a single byte and make the cache more granular, but increase
  83    overhead and reduce the effectiveness of the cache as a prefetcher.  */
  84 #define DCACHE_DEFAULT_LINE_SIZE 64
  85 static unsigned dcache_line_size = DCACHE_DEFAULT_LINE_SIZE;
  86
  87 /* Each cache block holds LINE_SIZE bytes of data
  88    starting at a multiple-of-LINE_SIZE address.  */
  89
  90 #define LINE_SIZE_MASK(dcache)  ((dcache->line_size - 1))
  91 #define XFORM(dcache, x)        ((x) & LINE_SIZE_MASK (dcache))
  92 #define MASK(dcache, x)         ((x) & ~LINE_SIZE_MASK (dcache))
  93
  94 struct dcache_block
  95 {
  96   /* For least-recently-allocated and free lists.  */
  97   struct dcache_block *prev;
  98   struct dcache_block *next;
  99
 100   CORE_ADDR addr;               /* address of data */
 101   int refs;                     /* # hits */
 102   gdb_byte data[1];             /* line_size bytes at given address */
 103 };
 104
 105 struct dcache_struct
 106 {
 107   splay_tree tree;
 108   struct dcache_block *oldest; /* least-recently-allocated list.  */
 109
 110   /* The free list is maintained identically to OLDEST to simplify
 111      the code: we only need one set of accessors.  */
 112   struct dcache_block *freelist;
 113
 114   /* The number of in-use lines in the cache.  */
 115   int size;
 116   CORE_ADDR line_size;  /* current line_size.  */
 117
 118   /* The ptid of last inferior to use cache or null_ptid.  */
 119   ptid_t ptid;
 120 };
 121
 122 typedef void (block_func) (struct dcache_block *block, void *param);
 123
 124 static struct dcache_block *dcache_hit (DCACHE *dcache, CORE_ADDR addr);
 125
 126 static int dcache_read_line (DCACHE *dcache, struct dcache_block *db);
 127
 128 static struct dcache_block *dcache_alloc (DCACHE *dcache, CORE_ADDR addr);
 129
 130 static void dcache_info (char *exp, int tty);
 131
 132 void _initialize_dcache (void);
 133
 134 static int dcache_enabled_p = 0; /* OBSOLETE */
 135
 136 static void
 137 show_dcache_enabled_p (struct ui_file *file, int from_tty,
 138                        struct cmd_list_element *c, const char *value)
 139 {
 140   fprintf_filtered (file, _("Deprecated remotecache flag is %s.\n"), value);
 141 }
 142
 143 static DCACHE *last_cache; /* Used by info dcache.  */
 144
 145 /* Add BLOCK to circular block list BLIST, behind the block at *BLIST.
 146    *BLIST is not updated (unless it was previously NULL of course).
 147    This is for the least-recently-allocated list's sake:
 148    BLIST points to the oldest block.
 149    ??? This makes for poor cache usage of the free list,
 150    but is it measurable?  */
 151
 152 static void
 153 append_block (struct dcache_block **blist, struct dcache_block *block)
 154 {
 155   if (*blist)
 156     {
 157       block->next = *blist;
 158       block->prev = (*blist)->prev;
 159       block->prev->next = block;
 160       (*blist)->prev = block;
 161       /* We don't update *BLIST here to maintain the invariant that for the
 162          least-recently-allocated list *BLIST points to the oldest block.  */
 163     }
 164   else
 165     {
 166       block->next = block;
 167       block->prev = block;
 168       *blist = block;
 169     }
 170 }
 171
 172 /* Remove BLOCK from circular block list BLIST.  */
 173
 174 static void
 175 remove_block (struct dcache_block **blist, struct dcache_block *block)
 176 {
 177   if (block->next == block)
 178     {
 179       *blist = NULL;
 180     }
 181   else
 182     {
 183       block->next->prev = block->prev;
 184       block->prev->next = block->next;
 185       /* If we removed the block *BLIST points to, shift it to the next block
 186          to maintain the invariant that for the least-recently-allocated list
 187          *BLIST points to the oldest block.  */
 188       if (*blist == block)
 189         *blist = block->next;
 190     }
 191 }
 192
 193 /* Iterate over all elements in BLIST, calling FUNC.
 194    PARAM is passed to FUNC.
 195    FUNC may remove the block it's passed, but only that block.  */
 196
 197 static void
 198 for_each_block (struct dcache_block **blist, block_func *func, void *param)
 199 {
 200   struct dcache_block *db;
 201
 202   if (*blist == NULL)
 203     return;
 204
 205   db = *blist;
 206   do
 207     {
 208       struct dcache_block *next = db->next;
 209
 210       func (db, param);
 211       db = next;
 212     }
 213   while (*blist && db != *blist);
 214 }
 215
 216 /* BLOCK_FUNC routine for dcache_free.  */
 217
 218 static void
 219 free_block (struct dcache_block *block, void *param)
 220 {
 221   xfree (block);
 222 }
 223
 224 /* Free a data cache.  */
 225
 226 void
 227 dcache_free (DCACHE *dcache)
 228 {
 229   if (last_cache == dcache)
 230     last_cache = NULL;
 231
 232   splay_tree_delete (dcache->tree);
 233   for_each_block (&dcache->oldest, free_block, NULL);
 234   for_each_block (&dcache->freelist, free_block, NULL);
 235   xfree (dcache);
 236 }
 237
 238
 239 /* BLOCK_FUNC function for dcache_invalidate.
 240    This doesn't remove the block from the oldest list on purpose.
 241    dcache_invalidate will do it later.  */
 242
 243 static void
 244 invalidate_block (struct dcache_block *block, void *param)
 245 {
 246   DCACHE *dcache = (DCACHE *) param;
 247
 248   splay_tree_remove (dcache->tree, (splay_tree_key) block->addr);
 249   append_block (&dcache->freelist, block);
 250 }
 251
 252 /* Free all the data cache blocks, thus discarding all cached data.  */
 253
 254 void
 255 dcache_invalidate (DCACHE *dcache)
 256 {
 257   for_each_block (&dcache->oldest, invalidate_block, dcache);
 258
 259   dcache->oldest = NULL;
 260   dcache->size = 0;
 261   dcache->ptid = null_ptid;
 262
 263   if (dcache->line_size != dcache_line_size)
 264     {
 265       /* We've been asked to use a different line size.
 266          All of our freelist blocks are now the wrong size, so free them.  */
 267
 268       for_each_block (&dcache->freelist, free_block, dcache);
 269       dcache->freelist = NULL;
 270       dcache->line_size = dcache_line_size;
 271     }
 272 }
 273
 274 /* Invalidate the line associated with ADDR.  */
 275
 276 static void
 277 dcache_invalidate_line (DCACHE *dcache, CORE_ADDR addr)
 278 {
 279   struct dcache_block *db = dcache_hit (dcache, addr);
 280
 281   if (db)
 282     {
 283       splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
 284       remove_block (&dcache->oldest, db);
 285       append_block (&dcache->freelist, db);
 286       --dcache->size;
 287     }
 288 }
 289
 290 /* If addr is present in the dcache, return the address of the block
 291    containing it.  Otherwise return NULL.  */
 292
 293 static struct dcache_block *
 294 dcache_hit (DCACHE *dcache, CORE_ADDR addr)
 295 {
 296   struct dcache_block *db;
 297
 298   splay_tree_node node = splay_tree_lookup (dcache->tree,
 299                                             (splay_tree_key) MASK (dcache, addr));
 300
 301   if (!node)
 302     return NULL;
 303
 304   db = (struct dcache_block *) node->value;
 305   db->refs++;
 306   return db;
 307 }
 308
 309 /* Fill a cache line from target memory.
 310    The result is 1 for success, 0 if the (entire) cache line
 311    wasn't readable.  */
 312
 313 static int
 314 dcache_read_line (DCACHE *dcache, struct dcache_block *db)
 315 {
 316   CORE_ADDR memaddr;
 317   gdb_byte *myaddr;
 318   int len;
 319   int res;
 320   int reg_len;
 321   struct mem_region *region;
 322
 323   len = dcache->line_size;
 324   memaddr = db->addr;
 325   myaddr  = db->data;
 326
 327   while (len > 0)
 328     {
 329       /* Don't overrun if this block is right at the end of the region.  */
 330       region = lookup_mem_region (memaddr);
 331       if (region->hi == 0 || memaddr + len < region->hi)
 332         reg_len = len;
 333       else
 334         reg_len = region->hi - memaddr;
 335
 336       /* Skip non-readable regions.  The cache attribute can be ignored,
 337          since we may be loading this for a stack access.  */
 338       if (region->attrib.mode == MEM_WO)
 339         {
 340           memaddr += reg_len;
 341           myaddr  += reg_len;
 342           len     -= reg_len;
 343           continue;
 344         }
 345
 346       res = target_read (&current_target, TARGET_OBJECT_RAW_MEMORY,
 347                          NULL, myaddr, memaddr, reg_len);
 348       if (res < reg_len)
 349         return 0;
 350
 351       memaddr += res;
 352       myaddr += res;
 353       len -= res;
 354     }
 355
 356   return 1;
 357 }
 358
 359 /* Get a free cache block, put or keep it on the valid list,
 360    and return its address.  */
 361
 362 static struct dcache_block *
 363 dcache_alloc (DCACHE *dcache, CORE_ADDR addr)
 364 {
 365   struct dcache_block *db;
 366
 367   if (dcache->size >= dcache_size)
 368     {
 369       /* Evict the least recently allocated line.  */
 370       db = dcache->oldest;
 371       remove_block (&dcache->oldest, db);
 372
 373       splay_tree_remove (dcache->tree, (splay_tree_key) db->addr);
 374     }
 375   else
 376     {
 377       db = dcache->freelist;
 378       if (db)
 379         remove_block (&dcache->freelist, db);
 380       else
 381         db = xmalloc (offsetof (struct dcache_block, data) +
 382                       dcache->line_size);
 383
 384       dcache->size++;
 385     }
 386
 387   db->addr = MASK (dcache, addr);
 388   db->refs = 0;
 389
 390   /* Put DB at the end of the list, it's the newest.  */
 391   append_block (&dcache->oldest, db);
 392
 393   splay_tree_insert (dcache->tree, (splay_tree_key) db->addr,
 394                      (splay_tree_value) db);
 395
 396   return db;
 397 }
 398
 399 /* Using the data cache DCACHE, store in *PTR the contents of the byte at
 400    address ADDR in the remote machine.
 401
 402    Returns 1 for success, 0 for error.  */
 403
 404 static int
 405 dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr)
 406 {
 407   struct dcache_block *db = dcache_hit (dcache, addr);
 408
 409   if (!db)
 410     {
 411       db = dcache_alloc (dcache, addr);
 412
 413       if (!dcache_read_line (dcache, db))
 414          return 0;
 415     }
 416
 417   *ptr = db->data[XFORM (dcache, addr)];
 418   return 1;
 419 }
 420
 421 /* Write the byte at PTR into ADDR in the data cache.
 422
 423    The caller is responsible for also promptly writing the data
 424    through to target memory.
 425
 426    If addr is not in cache, this function does nothing; writing to
 427    an area of memory which wasn't present in the cache doesn't cause
 428    it to be loaded in.
 429
 430    Always return 1 (meaning success) to simplify dcache_xfer_memory.  */
 431
 432 static int
 433 dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr)
 434 {
 435   struct dcache_block *db = dcache_hit (dcache, addr);
 436
 437   if (db)
 438     db->data[XFORM (dcache, addr)] = *ptr;
 439
 440   return 1;
 441 }
 442
 443 static int
 444 dcache_splay_tree_compare (splay_tree_key a, splay_tree_key b)
 445 {
 446   if (a > b)
 447     return 1;
 448   else if (a == b)
 449     return 0;
 450   else
 451     return -1;
 452 }
 453
 454 /* Allocate and initialize a data cache.  */
 455
 456 DCACHE *
 457 dcache_init (void)
 458 {
 459   DCACHE *dcache;
 460
 461   dcache = (DCACHE *) xmalloc (sizeof (*dcache));
 462
 463   dcache->tree = splay_tree_new (dcache_splay_tree_compare,
 464                                  NULL,
 465                                  NULL);
 466
 467   dcache->oldest = NULL;
 468   dcache->freelist = NULL;
 469   dcache->size = 0;
 470   dcache->line_size = dcache_line_size;
 471   dcache->ptid = null_ptid;
 472   last_cache = dcache;
 473
 474   return dcache;
 475 }
 476
 477
 478 /* Read or write LEN bytes from inferior memory at MEMADDR, transferring
 479    to or from debugger address MYADDR.  Write to inferior if SHOULD_WRITE is
 480    nonzero.
 481
 482    Return the number of bytes actually transfered, or -1 if the
 483    transfer is not supported or otherwise fails.  Return of a non-negative
 484    value less than LEN indicates that no further transfer is possible.
 485    NOTE: This is different than the to_xfer_partial interface, in which
 486    positive values less than LEN mean further transfers may be possible.  */
 487
 488 int
 489 dcache_xfer_memory (struct target_ops *ops, DCACHE *dcache,
 490                     CORE_ADDR memaddr, gdb_byte *myaddr,
 491                     int len, int should_write)
 492 {
 493   int i;
 494   int res;
 495   int (*xfunc) (DCACHE *dcache, CORE_ADDR addr, gdb_byte *ptr);
 496
 497   xfunc = should_write ? dcache_poke_byte : dcache_peek_byte;
 498
 499   /* If this is a different inferior from what we've recorded,
 500      flush the cache.  */
 501
 502   if (! ptid_equal (inferior_ptid, dcache->ptid))
 503     {
 504       dcache_invalidate (dcache);
 505       dcache->ptid = inferior_ptid;
 506     }
 507
 508   /* Do write-through first, so that if it fails, we don't write to
 509      the cache at all.  */
 510
 511   if (should_write)
 512     {
 513       res = target_write (ops, TARGET_OBJECT_RAW_MEMORY,
 514                           NULL, myaddr, memaddr, len);
 515       if (res <= 0)
 516         return res;
 517       /* Update LEN to what was actually written.  */
 518       len = res;
 519     }
 520
 521   for (i = 0; i < len; i++)
 522     {
 523       if (!xfunc (dcache, memaddr + i, myaddr + i))
 524         {
 525           /* That failed.  Discard its cache line so we don't have a
 526              partially read line.  */
 527           dcache_invalidate_line (dcache, memaddr + i);
 528           /* If we're writing, we still wrote LEN bytes.  */
 529           if (should_write)
 530             return len;
 531           else
 532             return i;
 533         }
 534     }
 535
 536   return len;
 537 }
 538
 539 /* FIXME: There would be some benefit to making the cache write-back and
 540    moving the writeback operation to a higher layer, as it could occur
 541    after a sequence of smaller writes have been completed (as when a stack
 542    frame is constructed for an inferior function call).  Note that only
 543    moving it up one level to target_xfer_memory[_partial]() is not
 544    sufficient since we want to coalesce memory transfers that are
 545    "logically" connected but not actually a single call to one of the
 546    memory transfer functions.  */
 547
 548 /* Just update any cache lines which are already present.  This is called
 549    by memory_xfer_partial in cases where the access would otherwise not go
 550    through the cache.  */
 551
 552 void
 553 dcache_update (DCACHE *dcache, CORE_ADDR memaddr, gdb_byte *myaddr, int len)
 554 {
 555   int i;
 556
 557   for (i = 0; i < len; i++)
 558     dcache_poke_byte (dcache, memaddr + i, myaddr + i);
 559 }
 560
 561 static void
 562 dcache_print_line (int index)
 563 {
 564   splay_tree_node n;
 565   struct dcache_block *db;
 566   int i, j;
 567
 568   if (!last_cache)
 569     {
 570       printf_filtered (_("No data cache available.\n"));
 571       return;
 572     }
 573
 574   n = splay_tree_min (last_cache->tree);
 575
 576   for (i = index; i > 0; --i)
 577     {
 578       if (!n)
 579         break;
 580       n = splay_tree_successor (last_cache->tree, n->key);
 581     }
 582
 583   if (!n)
 584     {
 585       printf_filtered (_("No such cache line exists.\n"));
 586       return;
 587     }
 588
 589   db = (struct dcache_block *) n->value;
 590
 591   printf_filtered (_("Line %d: address %s [%d hits]\n"),
 592                    index, paddress (target_gdbarch (), db->addr), db->refs);
 593
 594   for (j = 0; j < last_cache->line_size; j++)
 595     {
 596       printf_filtered ("%02x ", db->data[j]);
 597
 598       /* Print a newline every 16 bytes (48 characters).  */
 599       if ((j % 16 == 15) && (j != last_cache->line_size - 1))
 600         printf_filtered ("\n");
 601     }
 602   printf_filtered ("\n");
 603 }
 604
 605 static void
 606 dcache_info (char *exp, int tty)
 607 {
 608   splay_tree_node n;
 609   int i, refcount;
 610
 611   if (exp)
 612     {
 613       char *linestart;
 614
 615       i = strtol (exp, &linestart, 10);
 616       if (linestart == exp || i < 0)
 617         {
 618           printf_filtered (_("Usage: info dcache [linenumber]\n"));
 619           return;
 620         }
 621
 622       dcache_print_line (i);
 623       return;
 624     }
 625
 626   printf_filtered (_("Dcache %u lines of %u bytes each.\n"),
 627                    dcache_size,
 628                    last_cache ? (unsigned) last_cache->line_size
 629                    : dcache_line_size);
 630
 631   if (!last_cache || ptid_equal (last_cache->ptid, null_ptid))
 632     {
 633       printf_filtered (_("No data cache available.\n"));
 634       return;
 635     }
 636
 637   printf_filtered (_("Contains data for %s\n"),
 638                    target_pid_to_str (last_cache->ptid));
 639
 640   refcount = 0;
 641
 642   n = splay_tree_min (last_cache->tree);
 643   i = 0;
 644
 645   while (n)
 646     {
 647       struct dcache_block *db = (struct dcache_block *) n->value;
 648
 649       printf_filtered (_("Line %d: address %s [%d hits]\n"),
 650                        i, paddress (target_gdbarch (), db->addr), db->refs);
 651       i++;
 652       refcount += db->refs;
 653
 654       n = splay_tree_successor (last_cache->tree, n->key);
 655     }
 656
 657   printf_filtered (_("Cache state: %d active lines, %d hits\n"), i, refcount);
 658 }
 659
 660 static void
 661 set_dcache_size (char *args, int from_tty,
 662                  struct cmd_list_element *c)
 663 {
 664   if (dcache_size == 0)
 665     {
 666       dcache_size = DCACHE_DEFAULT_SIZE;
 667       error (_("Dcache size must be greater than 0."));
 668     }
 669   if (last_cache)
 670     dcache_invalidate (last_cache);
 671 }
 672
 673 static void
 674 set_dcache_line_size (char *args, int from_tty,
 675                       struct cmd_list_element *c)
 676 {
 677   if (dcache_line_size < 2
 678       || (dcache_line_size & (dcache_line_size - 1)) != 0)
 679     {
 680       unsigned d = dcache_line_size;
 681       dcache_line_size = DCACHE_DEFAULT_LINE_SIZE;
 682       error (_("Invalid dcache line size: %u (must be power of 2)."), d);
 683     }
 684   if (last_cache)
 685     dcache_invalidate (last_cache);
 686 }
 687
 688 static void
 689 set_dcache_command (char *arg, int from_tty)
 690 {
 691   printf_unfiltered (
 692      "\"set dcache\" must be followed by the name of a subcommand.\n");
 693   help_list (dcache_set_list, "set dcache ", -1, gdb_stdout);
 694 }
 695
 696 static void
 697 show_dcache_command (char *args, int from_tty)
 698 {
 699   cmd_show_list (dcache_show_list, from_tty, "");
 700 }
 701
 702 void
 703 _initialize_dcache (void)
 704 {
 705   add_setshow_boolean_cmd ("remotecache", class_support,
 706                            &dcache_enabled_p, _("\
 707 Set cache use for remote targets."), _("\
 708 Show cache use for remote targets."), _("\
 709 This used to enable the data cache for remote targets.  The cache\n\
 710 functionality is now controlled by the memory region system and the\n\
 711 \"stack-cache\" flag; \"remotecache\" now does nothing and\n\
 712 exists only for compatibility reasons."),
 713                            NULL,
 714                            show_dcache_enabled_p,
 715                            &setlist, &showlist);
 716
 717   add_info ("dcache", dcache_info,
 718             _("\
 719 Print information on the dcache performance.\n\
 720 With no arguments, this command prints the cache configuration and a\n\
 721 summary of each line in the cache.  Use \"info dcache <lineno> to dump\"\n\
 722 the contents of a given line."));
 723
 724   add_prefix_cmd ("dcache", class_obscure, set_dcache_command, _("\
 725 Use this command to set number of lines in dcache and line-size."),
 726                   &dcache_set_list, "set dcache ", /*allow_unknown*/0, &setlist);
 727   add_prefix_cmd ("dcache", class_obscure, show_dcache_command, _("\
 728 Show dcachesettings."),
 729                   &dcache_show_list, "show dcache ", /*allow_unknown*/0, &showlist);
 730
 731   add_setshow_uinteger_cmd ("line-size", class_obscure,
 732                             &dcache_line_size, _("\
 733 Set dcache line size in bytes (must be power of 2)."), _("\
 734 Show dcache line size."),
 735                             NULL,
 736                             set_dcache_line_size,
 737                             NULL,
 738                             &dcache_set_list, &dcache_show_list);
 739   add_setshow_uinteger_cmd ("size", class_obscure,
 740                             &dcache_size, _("\
 741 Set number of dcache lines."), _("\
 742 Show number of dcache lines."),
 743                             NULL,
 744                             set_dcache_size,
 745                             NULL,
 746                             &dcache_set_list, &dcache_show_list);
 747 }