drivers/acpi/namespace/nssearch.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nssearch - Namespace search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2007, R. Byron Moore
   9  * All rights reserved.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions, and the following disclaimer,
  16  *    without modification.
  17  * 2. Redistributions in binary form must reproduce at minimum a disclaimer
  18  *    substantially similar to the "NO WARRANTY" disclaimer below
  19  *    ("Disclaimer") and any redistribution must be conditioned upon
  20  *    including a substantially similar Disclaimer requirement for further
  21  *    binary redistribution.
  22  * 3. Neither the names of the above-listed copyright holders nor the names
  23  *    of any contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * Alternatively, this software may be distributed under the terms of the
  27  * GNU General Public License ("GPL") version 2 as published by the Free
  28  * Software Foundation.
  29  *
  30  * NO WARRANTY
  31  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  32  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  33  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
  34  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  35  * HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  36  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  37  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  38  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  39  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  40  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  41  * POSSIBILITY OF SUCH DAMAGES.
  42  */
  43
  44 #include <acpi/acpi.h>
  45 #include <acpi/acnamesp.h>
  46
  47 #define _COMPONENT          ACPI_NAMESPACE
  48 ACPI_MODULE_NAME("nssearch")
  49
  50 /* Local prototypes */
  51 static acpi_status
  52 acpi_ns_search_parent_tree(u32 target_name,
  53                            struct acpi_namespace_node *node,
  54                            acpi_object_type type,
  55                            struct acpi_namespace_node **return_node);
  56
  57 /*******************************************************************************
  58  *
  59  * FUNCTION:    acpi_ns_search_one_scope
  60  *
  61  * PARAMETERS:  target_name     - Ascii ACPI name to search for
  62  *              parent_node     - Starting node where search will begin
  63  *              Type            - Object type to match
  64  *              return_node     - Where the matched Named obj is returned
  65  *
  66  * RETURN:      Status
  67  *
  68  * DESCRIPTION: Search a single level of the namespace. Performs a
  69  *              simple search of the specified level, and does not add
  70  *              entries or search parents.
  71  *
  72  *
  73  *      Named object lists are built (and subsequently dumped) in the
  74  *      order in which the names are encountered during the namespace load;
  75  *
  76  *      All namespace searching is linear in this implementation, but
  77  *      could be easily modified to support any improved search
  78  *      algorithm. However, the linear search was chosen for simplicity
  79  *      and because the trees are small and the other interpreter
  80  *      execution overhead is relatively high.
  81  *
  82  *      Note: CPU execution analysis has shown that the AML interpreter spends
  83  *      a very small percentage of its time searching the namespace. Therefore,
  84  *      the linear search seems to be sufficient, as there would seem to be
  85  *      little value in improving the search.
  86  *
  87  ******************************************************************************/
  88
  89 acpi_status
  90 acpi_ns_search_one_scope(u32 target_name,
  91                          struct acpi_namespace_node *parent_node,
  92                          acpi_object_type type,
  93                          struct acpi_namespace_node **return_node)
  94 {
  95         struct acpi_namespace_node *node;
  96
  97         ACPI_FUNCTION_TRACE(ns_search_one_scope);
  98
  99 #ifdef ACPI_DEBUG_OUTPUT
 100         if (ACPI_LV_NAMES & acpi_dbg_level) {
 101                 char *scope_name;
 102
 103                 scope_name = acpi_ns_get_external_pathname(parent_node);
 104                 if (scope_name) {
 105                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 106                                           "Searching %s (%p) For [%4.4s] (%s)\n",
 107                                           scope_name, parent_node,
 108                                           ACPI_CAST_PTR(char, &target_name),
 109                                           acpi_ut_get_type_name(type)));
 110
 111                         ACPI_FREE(scope_name);
 112                 }
 113         }
 114 #endif
 115
 116         /*
 117          * Search for name at this namespace level, which is to say that we
 118          * must search for the name among the children of this object
 119          */
 120         node = parent_node->child;
 121         while (node) {
 122
 123                 /* Check for match against the name */
 124
 125                 if (node->name.integer == target_name) {
 126
 127                         /* Resolve a control method alias if any */
 128
 129                         if (acpi_ns_get_type(node) ==
 130                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 131                                 node =
 132                                     ACPI_CAST_PTR(struct acpi_namespace_node,
 133                                                   node->object);
 134                         }
 135
 136                         /* Found matching entry */
 137
 138                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 139                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 140                                           ACPI_CAST_PTR(char, &target_name),
 141                                           acpi_ut_get_type_name(node->type),
 142                                           node,
 143                                           acpi_ut_get_node_name(parent_node),
 144                                           parent_node));
 145
 146                         *return_node = node;
 147                         return_ACPI_STATUS(AE_OK);
 148                 }
 149
 150                 /*
 151                  * The last entry in the list points back to the parent,
 152                  * so a flag is used to indicate the end-of-list
 153                  */
 154                 if (node->flags & ANOBJ_END_OF_PEER_LIST) {
 155
 156                         /* Searched entire list, we are done */
 157
 158                         break;
 159                 }
 160
 161                 /* Didn't match name, move on to the next peer object */
 162
 163                 node = node->peer;
 164         }
 165
 166         /* Searched entire namespace level, not found */
 167
 168         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 169                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
 170                           ACPI_CAST_PTR(char, &target_name),
 171                           acpi_ut_get_type_name(type),
 172                           acpi_ut_get_node_name(parent_node), parent_node,
 173                           parent_node->child));
 174
 175         return_ACPI_STATUS(AE_NOT_FOUND);
 176 }
 177
 178 /*******************************************************************************
 179  *
 180  * FUNCTION:    acpi_ns_search_parent_tree
 181  *
 182  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 183  *              Node            - Starting node where search will begin
 184  *              Type            - Object type to match
 185  *              return_node     - Where the matched Node is returned
 186  *
 187  * RETURN:      Status
 188  *
 189  * DESCRIPTION: Called when a name has not been found in the current namespace
 190  *              level. Before adding it or giving up, ACPI scope rules require
 191  *              searching enclosing scopes in cases identified by acpi_ns_local().
 192  *
 193  *              "A name is located by finding the matching name in the current
 194  *              name space, and then in the parent name space. If the parent
 195  *              name space does not contain the name, the search continues
 196  *              recursively until either the name is found or the name space
 197  *              does not have a parent (the root of the name space). This
 198  *              indicates that the name is not found" (From ACPI Specification,
 199  *              section 5.3)
 200  *
 201  ******************************************************************************/
 202
 203 static acpi_status
 204 acpi_ns_search_parent_tree(u32 target_name,
 205                            struct acpi_namespace_node *node,
 206                            acpi_object_type type,
 207                            struct acpi_namespace_node **return_node)
 208 {
 209         acpi_status status;
 210         struct acpi_namespace_node *parent_node;
 211
 212         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 213
 214         parent_node = acpi_ns_get_parent_node(node);
 215
 216         /*
 217          * If there is no parent (i.e., we are at the root) or type is "local",
 218          * we won't be searching the parent tree.
 219          */
 220         if (!parent_node) {
 221                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 222                                   ACPI_CAST_PTR(char, &target_name)));
 223                 return_ACPI_STATUS(AE_NOT_FOUND);
 224         }
 225
 226         if (acpi_ns_local(type)) {
 227                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 228                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 229                                   ACPI_CAST_PTR(char, &target_name),
 230                                   acpi_ut_get_type_name(type)));
 231                 return_ACPI_STATUS(AE_NOT_FOUND);
 232         }
 233
 234         /* Search the parent tree */
 235
 236         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 237                           "Searching parent [%4.4s] for [%4.4s]\n",
 238                           acpi_ut_get_node_name(parent_node),
 239                           ACPI_CAST_PTR(char, &target_name)));
 240
 241         /*
 242          * Search parents until target is found or we have backed up to the root
 243          */
 244         while (parent_node) {
 245                 /*
 246                  * Search parent scope. Use TYPE_ANY because we don't care about the
 247                  * object type at this point, we only care about the existence of
 248                  * the actual name we are searching for. Typechecking comes later.
 249                  */
 250                 status =
 251                     acpi_ns_search_one_scope(target_name, parent_node,
 252                                              ACPI_TYPE_ANY, return_node);
 253                 if (ACPI_SUCCESS(status)) {
 254                         return_ACPI_STATUS(status);
 255                 }
 256
 257                 /* Not found here, go up another level (until we reach the root) */
 258
 259                 parent_node = acpi_ns_get_parent_node(parent_node);
 260         }
 261
 262         /* Not found in parent tree */
 263
 264         return_ACPI_STATUS(AE_NOT_FOUND);
 265 }
 266
 267 /*******************************************************************************
 268  *
 269  * FUNCTION:    acpi_ns_search_and_enter
 270  *
 271  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 272  *              walk_state          - Current state of the walk
 273  *              Node                - Starting node where search will begin
 274  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 275  *                                    Otherwise,search only.
 276  *              Type                - Object type to match
 277  *              Flags               - Flags describing the search restrictions
 278  *              return_node         - Where the Node is returned
 279  *
 280  * RETURN:      Status
 281  *
 282  * DESCRIPTION: Search for a name segment in a single namespace level,
 283  *              optionally adding it if it is not found. If the passed
 284  *              Type is not Any and the type previously stored in the
 285  *              entry was Any (i.e. unknown), update the stored type.
 286  *
 287  *              In ACPI_IMODE_EXECUTE, search only.
 288  *              In other modes, search and add if not found.
 289  *
 290  ******************************************************************************/
 291
 292 acpi_status
 293 acpi_ns_search_and_enter(u32 target_name,
 294                          struct acpi_walk_state *walk_state,
 295                          struct acpi_namespace_node *node,
 296                          acpi_interpreter_mode interpreter_mode,
 297                          acpi_object_type type,
 298                          u32 flags, struct acpi_namespace_node **return_node)
 299 {
 300         acpi_status status;
 301         struct acpi_namespace_node *new_node;
 302
 303         ACPI_FUNCTION_TRACE(ns_search_and_enter);
 304
 305         /* Parameter validation */
 306
 307         if (!node || !target_name || !return_node) {
 308                 ACPI_ERROR((AE_INFO,
 309                             "Null parameter: Node %p Name %X ReturnNode %p",
 310                             node, target_name, return_node));
 311                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 312         }
 313
 314         /*
 315          * Name must consist of valid ACPI characters. We will repair the name if
 316          * necessary because we don't want to abort because of this, but we want
 317          * all namespace names to be printable. A warning message is appropriate.
 318          *
 319          * This issue came up because there are in fact machines that exhibit
 320          * this problem, and we want to be able to enable ACPI support for them,
 321          * even though there are a few bad names.
 322          */
 323         if (!acpi_ut_valid_acpi_name(target_name)) {
 324                 target_name =
 325                     acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
 326
 327                 /* Report warning only if in strict mode or debug mode */
 328
 329                 if (!acpi_gbl_enable_interpreter_slack) {
 330                         ACPI_WARNING((AE_INFO,
 331                                       "Found bad character(s) in name, repaired: [%4.4s]\n",
 332                                       ACPI_CAST_PTR(char, &target_name)));
 333                 } else {
 334                         ACPI_DEBUG_PRINT((ACPI_DB_WARN,
 335                                           "Found bad character(s) in name, repaired: [%4.4s]\n",
 336                                           ACPI_CAST_PTR(char, &target_name)));
 337                 }
 338         }
 339
 340         /* Try to find the name in the namespace level specified by the caller */
 341
 342         *return_node = ACPI_ENTRY_NOT_FOUND;
 343         status = acpi_ns_search_one_scope(target_name, node, type, return_node);
 344         if (status != AE_NOT_FOUND) {
 345                 /*
 346                  * If we found it AND the request specifies that a find is an error,
 347                  * return the error
 348                  */
 349                 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
 350                         status = AE_ALREADY_EXISTS;
 351                 }
 352
 353                 /* Either found it or there was an error: finished either way */
 354
 355                 return_ACPI_STATUS(status);
 356         }
 357
 358         /*
 359          * The name was not found. If we are NOT performing the first pass
 360          * (name entry) of loading the namespace, search the parent tree (all the
 361          * way to the root if necessary.) We don't want to perform the parent
 362          * search when the namespace is actually being loaded. We want to perform
 363          * the search when namespace references are being resolved (load pass 2)
 364          * and during the execution phase.
 365          */
 366         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 367             (flags & ACPI_NS_SEARCH_PARENT)) {
 368                 /*
 369                  * Not found at this level - search parent tree according to the
 370                  * ACPI specification
 371                  */
 372                 status =
 373                     acpi_ns_search_parent_tree(target_name, node, type,
 374                                                return_node);
 375                 if (ACPI_SUCCESS(status)) {
 376                         return_ACPI_STATUS(status);
 377                 }
 378         }
 379
 380         /* In execute mode, just search, never add names. Exit now */
 381
 382         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 383                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 384                                   "%4.4s Not found in %p [Not adding]\n",
 385                                   ACPI_CAST_PTR(char, &target_name), node));
 386
 387                 return_ACPI_STATUS(AE_NOT_FOUND);
 388         }
 389
 390         /* Create the new named object */
 391
 392         new_node = acpi_ns_create_node(target_name);
 393         if (!new_node) {
 394                 return_ACPI_STATUS(AE_NO_MEMORY);
 395         }
 396 #ifdef ACPI_ASL_COMPILER
 397         /*
 398          * Node is an object defined by an External() statement
 399          */
 400         if (flags & ACPI_NS_EXTERNAL) {
 401                 new_node->flags |= ANOBJ_IS_EXTERNAL;
 402         }
 403 #endif
 404
 405         if (flags & ACPI_NS_TEMPORARY) {
 406                 new_node->flags |= ANOBJ_TEMPORARY;
 407         }
 408
 409         /* Install the new object into the parent's list of children */
 410
 411         acpi_ns_install_node(walk_state, node, new_node, type);
 412         *return_node = new_node;
 413         return_ACPI_STATUS(AE_OK);
 414 }