drivers/acpi/namespace/nssearch.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nssearch - Namespace search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2008, Intel Corp.
   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/accommon.h>
  46 #include <acpi/acnamesp.h>
  47
  48 #define _COMPONENT          ACPI_NAMESPACE
  49 ACPI_MODULE_NAME("nssearch")
  50
  51 /* Local prototypes */
  52 static acpi_status
  53 acpi_ns_search_parent_tree(u32 target_name,
  54                            struct acpi_namespace_node *node,
  55                            acpi_object_type type,
  56                            struct acpi_namespace_node **return_node);
  57
  58 /*******************************************************************************
  59  *
  60  * FUNCTION:    acpi_ns_search_one_scope
  61  *
  62  * PARAMETERS:  target_name     - Ascii ACPI name to search for
  63  *              parent_node     - Starting node where search will begin
  64  *              Type            - Object type to match
  65  *              return_node     - Where the matched Named obj is returned
  66  *
  67  * RETURN:      Status
  68  *
  69  * DESCRIPTION: Search a single level of the namespace. Performs a
  70  *              simple search of the specified level, and does not add
  71  *              entries or search parents.
  72  *
  73  *
  74  *      Named object lists are built (and subsequently dumped) in the
  75  *      order in which the names are encountered during the namespace load;
  76  *
  77  *      All namespace searching is linear in this implementation, but
  78  *      could be easily modified to support any improved search
  79  *      algorithm. However, the linear search was chosen for simplicity
  80  *      and because the trees are small and the other interpreter
  81  *      execution overhead is relatively high.
  82  *
  83  *      Note: CPU execution analysis has shown that the AML interpreter spends
  84  *      a very small percentage of its time searching the namespace. Therefore,
  85  *      the linear search seems to be sufficient, as there would seem to be
  86  *      little value in improving the search.
  87  *
  88  ******************************************************************************/
  89
  90 acpi_status
  91 acpi_ns_search_one_scope(u32 target_name,
  92                          struct acpi_namespace_node *parent_node,
  93                          acpi_object_type type,
  94                          struct acpi_namespace_node **return_node)
  95 {
  96         struct acpi_namespace_node *node;
  97
  98         ACPI_FUNCTION_TRACE(ns_search_one_scope);
  99
 100 #ifdef ACPI_DEBUG_OUTPUT
 101         if (ACPI_LV_NAMES & acpi_dbg_level) {
 102                 char *scope_name;
 103
 104                 scope_name = acpi_ns_get_external_pathname(parent_node);
 105                 if (scope_name) {
 106                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 107                                           "Searching %s (%p) For [%4.4s] (%s)\n",
 108                                           scope_name, parent_node,
 109                                           ACPI_CAST_PTR(char, &target_name),
 110                                           acpi_ut_get_type_name(type)));
 111
 112                         ACPI_FREE(scope_name);
 113                 }
 114         }
 115 #endif
 116
 117         /*
 118          * Search for name at this namespace level, which is to say that we
 119          * must search for the name among the children of this object
 120          */
 121         node = parent_node->child;
 122         while (node) {
 123
 124                 /* Check for match against the name */
 125
 126                 if (node->name.integer == target_name) {
 127
 128                         /* Resolve a control method alias if any */
 129
 130                         if (acpi_ns_get_type(node) ==
 131                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 132                                 node =
 133                                     ACPI_CAST_PTR(struct acpi_namespace_node,
 134                                                   node->object);
 135                         }
 136
 137                         /* Found matching entry */
 138
 139                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 140                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 141                                           ACPI_CAST_PTR(char, &target_name),
 142                                           acpi_ut_get_type_name(node->type),
 143                                           node,
 144                                           acpi_ut_get_node_name(parent_node),
 145                                           parent_node));
 146
 147                         *return_node = node;
 148                         return_ACPI_STATUS(AE_OK);
 149                 }
 150
 151                 /*
 152                  * The last entry in the list points back to the parent,
 153                  * so a flag is used to indicate the end-of-list
 154                  */
 155                 if (node->flags & ANOBJ_END_OF_PEER_LIST) {
 156
 157                         /* Searched entire list, we are done */
 158
 159                         break;
 160                 }
 161
 162                 /* Didn't match name, move on to the next peer object */
 163
 164                 node = node->peer;
 165         }
 166
 167         /* Searched entire namespace level, not found */
 168
 169         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 170                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] %p first child %p\n",
 171                           ACPI_CAST_PTR(char, &target_name),
 172                           acpi_ut_get_type_name(type),
 173                           acpi_ut_get_node_name(parent_node), parent_node,
 174                           parent_node->child));
 175
 176         return_ACPI_STATUS(AE_NOT_FOUND);
 177 }
 178
 179 /*******************************************************************************
 180  *
 181  * FUNCTION:    acpi_ns_search_parent_tree
 182  *
 183  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 184  *              Node            - Starting node where search will begin
 185  *              Type            - Object type to match
 186  *              return_node     - Where the matched Node is returned
 187  *
 188  * RETURN:      Status
 189  *
 190  * DESCRIPTION: Called when a name has not been found in the current namespace
 191  *              level. Before adding it or giving up, ACPI scope rules require
 192  *              searching enclosing scopes in cases identified by acpi_ns_local().
 193  *
 194  *              "A name is located by finding the matching name in the current
 195  *              name space, and then in the parent name space. If the parent
 196  *              name space does not contain the name, the search continues
 197  *              recursively until either the name is found or the name space
 198  *              does not have a parent (the root of the name space). This
 199  *              indicates that the name is not found" (From ACPI Specification,
 200  *              section 5.3)
 201  *
 202  ******************************************************************************/
 203
 204 static acpi_status
 205 acpi_ns_search_parent_tree(u32 target_name,
 206                            struct acpi_namespace_node *node,
 207                            acpi_object_type type,
 208                            struct acpi_namespace_node **return_node)
 209 {
 210         acpi_status status;
 211         struct acpi_namespace_node *parent_node;
 212
 213         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 214
 215         parent_node = acpi_ns_get_parent_node(node);
 216
 217         /*
 218          * If there is no parent (i.e., we are at the root) or type is "local",
 219          * we won't be searching the parent tree.
 220          */
 221         if (!parent_node) {
 222                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 223                                   ACPI_CAST_PTR(char, &target_name)));
 224                 return_ACPI_STATUS(AE_NOT_FOUND);
 225         }
 226
 227         if (acpi_ns_local(type)) {
 228                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 229                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 230                                   ACPI_CAST_PTR(char, &target_name),
 231                                   acpi_ut_get_type_name(type)));
 232                 return_ACPI_STATUS(AE_NOT_FOUND);
 233         }
 234
 235         /* Search the parent tree */
 236
 237         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 238                           "Searching parent [%4.4s] for [%4.4s]\n",
 239                           acpi_ut_get_node_name(parent_node),
 240                           ACPI_CAST_PTR(char, &target_name)));
 241
 242         /*
 243          * Search parents until target is found or we have backed up to the root
 244          */
 245         while (parent_node) {
 246                 /*
 247                  * Search parent scope. Use TYPE_ANY because we don't care about the
 248                  * object type at this point, we only care about the existence of
 249                  * the actual name we are searching for. Typechecking comes later.
 250                  */
 251                 status =
 252                     acpi_ns_search_one_scope(target_name, parent_node,
 253                                              ACPI_TYPE_ANY, return_node);
 254                 if (ACPI_SUCCESS(status)) {
 255                         return_ACPI_STATUS(status);
 256                 }
 257
 258                 /* Not found here, go up another level (until we reach the root) */
 259
 260                 parent_node = acpi_ns_get_parent_node(parent_node);
 261         }
 262
 263         /* Not found in parent tree */
 264
 265         return_ACPI_STATUS(AE_NOT_FOUND);
 266 }
 267
 268 /*******************************************************************************
 269  *
 270  * FUNCTION:    acpi_ns_search_and_enter
 271  *
 272  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 273  *              walk_state          - Current state of the walk
 274  *              Node                - Starting node where search will begin
 275  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 276  *                                    Otherwise,search only.
 277  *              Type                - Object type to match
 278  *              Flags               - Flags describing the search restrictions
 279  *              return_node         - Where the Node is returned
 280  *
 281  * RETURN:      Status
 282  *
 283  * DESCRIPTION: Search for a name segment in a single namespace level,
 284  *              optionally adding it if it is not found. If the passed
 285  *              Type is not Any and the type previously stored in the
 286  *              entry was Any (i.e. unknown), update the stored type.
 287  *
 288  *              In ACPI_IMODE_EXECUTE, search only.
 289  *              In other modes, search and add if not found.
 290  *
 291  ******************************************************************************/
 292
 293 acpi_status
 294 acpi_ns_search_and_enter(u32 target_name,
 295                          struct acpi_walk_state *walk_state,
 296                          struct acpi_namespace_node *node,
 297                          acpi_interpreter_mode interpreter_mode,
 298                          acpi_object_type type,
 299                          u32 flags, struct acpi_namespace_node **return_node)
 300 {
 301         acpi_status status;
 302         struct acpi_namespace_node *new_node;
 303
 304         ACPI_FUNCTION_TRACE(ns_search_and_enter);
 305
 306         /* Parameter validation */
 307
 308         if (!node || !target_name || !return_node) {
 309                 ACPI_ERROR((AE_INFO,
 310                             "Null parameter: Node %p Name %X ReturnNode %p",
 311                             node, target_name, return_node));
 312                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 313         }
 314
 315         /*
 316          * Name must consist of valid ACPI characters. We will repair the name if
 317          * necessary because we don't want to abort because of this, but we want
 318          * all namespace names to be printable. A warning message is appropriate.
 319          *
 320          * This issue came up because there are in fact machines that exhibit
 321          * this problem, and we want to be able to enable ACPI support for them,
 322          * even though there are a few bad names.
 323          */
 324         if (!acpi_ut_valid_acpi_name(target_name)) {
 325                 target_name =
 326                     acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
 327
 328                 /* Report warning only if in strict mode or debug mode */
 329
 330                 if (!acpi_gbl_enable_interpreter_slack) {
 331                         ACPI_WARNING((AE_INFO,
 332                                       "Found bad character(s) in name, repaired: [%4.4s]\n",
 333                                       ACPI_CAST_PTR(char, &target_name)));
 334                 } else {
 335                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 336                                           "Found bad character(s) in name, repaired: [%4.4s]\n",
 337                                           ACPI_CAST_PTR(char, &target_name)));
 338                 }
 339         }
 340
 341         /* Try to find the name in the namespace level specified by the caller */
 342
 343         *return_node = ACPI_ENTRY_NOT_FOUND;
 344         status = acpi_ns_search_one_scope(target_name, node, type, return_node);
 345         if (status != AE_NOT_FOUND) {
 346                 /*
 347                  * If we found it AND the request specifies that a find is an error,
 348                  * return the error
 349                  */
 350                 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
 351                         status = AE_ALREADY_EXISTS;
 352                 }
 353
 354                 /* Either found it or there was an error: finished either way */
 355
 356                 return_ACPI_STATUS(status);
 357         }
 358
 359         /*
 360          * The name was not found. If we are NOT performing the first pass
 361          * (name entry) of loading the namespace, search the parent tree (all the
 362          * way to the root if necessary.) We don't want to perform the parent
 363          * search when the namespace is actually being loaded. We want to perform
 364          * the search when namespace references are being resolved (load pass 2)
 365          * and during the execution phase.
 366          */
 367         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 368             (flags & ACPI_NS_SEARCH_PARENT)) {
 369                 /*
 370                  * Not found at this level - search parent tree according to the
 371                  * ACPI specification
 372                  */
 373                 status =
 374                     acpi_ns_search_parent_tree(target_name, node, type,
 375                                                return_node);
 376                 if (ACPI_SUCCESS(status)) {
 377                         return_ACPI_STATUS(status);
 378                 }
 379         }
 380
 381         /* In execute mode, just search, never add names. Exit now */
 382
 383         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 384                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 385                                   "%4.4s Not found in %p [Not adding]\n",
 386                                   ACPI_CAST_PTR(char, &target_name), node));
 387
 388                 return_ACPI_STATUS(AE_NOT_FOUND);
 389         }
 390
 391         /* Create the new named object */
 392
 393         new_node = acpi_ns_create_node(target_name);
 394         if (!new_node) {
 395                 return_ACPI_STATUS(AE_NO_MEMORY);
 396         }
 397 #ifdef ACPI_ASL_COMPILER
 398         /*
 399          * Node is an object defined by an External() statement
 400          */
 401         if (flags & ACPI_NS_EXTERNAL) {
 402                 new_node->flags |= ANOBJ_IS_EXTERNAL;
 403         }
 404 #endif
 405
 406         if (flags & ACPI_NS_TEMPORARY) {
 407                 new_node->flags |= ANOBJ_TEMPORARY;
 408         }
 409
 410         /* Install the new object into the parent's list of children */
 411
 412         acpi_ns_install_node(walk_state, node, new_node, type);
 413         *return_node = new_node;
 414         return_ACPI_STATUS(AE_OK);
 415 }