drivers/acpi/acpica/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 "accommon.h"
  46 #include "acnamesp.h"
  47
  48 #ifdef ACPI_ASL_COMPILER
  49 #include "amlcode.h"
  50 #endif
  51
  52 #define _COMPONENT          ACPI_NAMESPACE
  53 ACPI_MODULE_NAME("nssearch")
  54
  55 /* Local prototypes */
  56 static acpi_status
  57 acpi_ns_search_parent_tree(u32 target_name,
  58                            struct acpi_namespace_node *node,
  59                            acpi_object_type type,
  60                            struct acpi_namespace_node **return_node);
  61
  62 /*******************************************************************************
  63  *
  64  * FUNCTION:    acpi_ns_search_one_scope
  65  *
  66  * PARAMETERS:  target_name     - Ascii ACPI name to search for
  67  *              parent_node     - Starting node where search will begin
  68  *              Type            - Object type to match
  69  *              return_node     - Where the matched Named obj is returned
  70  *
  71  * RETURN:      Status
  72  *
  73  * DESCRIPTION: Search a single level of the namespace. Performs a
  74  *              simple search of the specified level, and does not add
  75  *              entries or search parents.
  76  *
  77  *
  78  *      Named object lists are built (and subsequently dumped) in the
  79  *      order in which the names are encountered during the namespace load;
  80  *
  81  *      All namespace searching is linear in this implementation, but
  82  *      could be easily modified to support any improved search
  83  *      algorithm. However, the linear search was chosen for simplicity
  84  *      and because the trees are small and the other interpreter
  85  *      execution overhead is relatively high.
  86  *
  87  *      Note: CPU execution analysis has shown that the AML interpreter spends
  88  *      a very small percentage of its time searching the namespace. Therefore,
  89  *      the linear search seems to be sufficient, as there would seem to be
  90  *      little value in improving the search.
  91  *
  92  ******************************************************************************/
  93
  94 acpi_status
  95 acpi_ns_search_one_scope(u32 target_name,
  96                          struct acpi_namespace_node *parent_node,
  97                          acpi_object_type type,
  98                          struct acpi_namespace_node **return_node)
  99 {
 100         struct acpi_namespace_node *node;
 101
 102         ACPI_FUNCTION_TRACE(ns_search_one_scope);
 103
 104 #ifdef ACPI_DEBUG_OUTPUT
 105         if (ACPI_LV_NAMES & acpi_dbg_level) {
 106                 char *scope_name;
 107
 108                 scope_name = acpi_ns_get_external_pathname(parent_node);
 109                 if (scope_name) {
 110                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 111                                           "Searching %s (%p) For [%4.4s] (%s)\n",
 112                                           scope_name, parent_node,
 113                                           ACPI_CAST_PTR(char, &target_name),
 114                                           acpi_ut_get_type_name(type)));
 115
 116                         ACPI_FREE(scope_name);
 117                 }
 118         }
 119 #endif
 120
 121         /*
 122          * Search for name at this namespace level, which is to say that we
 123          * must search for the name among the children of this object
 124          */
 125         node = parent_node->child;
 126         while (node) {
 127
 128                 /* Check for match against the name */
 129
 130                 if (node->name.integer == target_name) {
 131
 132                         /* Resolve a control method alias if any */
 133
 134                         if (acpi_ns_get_type(node) ==
 135                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 136                                 node =
 137                                     ACPI_CAST_PTR(struct acpi_namespace_node,
 138                                                   node->object);
 139                         }
 140
 141                         /* Found matching entry */
 142
 143                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 144                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 145                                           ACPI_CAST_PTR(char, &target_name),
 146                                           acpi_ut_get_type_name(node->type),
 147                                           node,
 148                                           acpi_ut_get_node_name(parent_node),
 149                                           parent_node));
 150
 151                         *return_node = node;
 152                         return_ACPI_STATUS(AE_OK);
 153                 }
 154
 155                 /*
 156                  * The last entry in the list points back to the parent,
 157                  * so a flag is used to indicate the end-of-list
 158                  */
 159                 if (node->flags & ANOBJ_END_OF_PEER_LIST) {
 160
 161                         /* Searched entire list, we are done */
 162
 163                         break;
 164                 }
 165
 166                 /* Didn't match name, move on to the next peer object */
 167
 168                 node = node->peer;
 169         }
 170
 171         /* Searched entire namespace level, not found */
 172
 173         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 174                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] "
 175                           "%p first child %p\n",
 176                           ACPI_CAST_PTR(char, &target_name),
 177                           acpi_ut_get_type_name(type),
 178                           acpi_ut_get_node_name(parent_node), parent_node,
 179                           parent_node->child));
 180
 181         return_ACPI_STATUS(AE_NOT_FOUND);
 182 }
 183
 184 /*******************************************************************************
 185  *
 186  * FUNCTION:    acpi_ns_search_parent_tree
 187  *
 188  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 189  *              Node            - Starting node where search will begin
 190  *              Type            - Object type to match
 191  *              return_node     - Where the matched Node is returned
 192  *
 193  * RETURN:      Status
 194  *
 195  * DESCRIPTION: Called when a name has not been found in the current namespace
 196  *              level. Before adding it or giving up, ACPI scope rules require
 197  *              searching enclosing scopes in cases identified by acpi_ns_local().
 198  *
 199  *              "A name is located by finding the matching name in the current
 200  *              name space, and then in the parent name space. If the parent
 201  *              name space does not contain the name, the search continues
 202  *              recursively until either the name is found or the name space
 203  *              does not have a parent (the root of the name space). This
 204  *              indicates that the name is not found" (From ACPI Specification,
 205  *              section 5.3)
 206  *
 207  ******************************************************************************/
 208
 209 static acpi_status
 210 acpi_ns_search_parent_tree(u32 target_name,
 211                            struct acpi_namespace_node *node,
 212                            acpi_object_type type,
 213                            struct acpi_namespace_node **return_node)
 214 {
 215         acpi_status status;
 216         struct acpi_namespace_node *parent_node;
 217
 218         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 219
 220         parent_node = acpi_ns_get_parent_node(node);
 221
 222         /*
 223          * If there is no parent (i.e., we are at the root) or type is "local",
 224          * we won't be searching the parent tree.
 225          */
 226         if (!parent_node) {
 227                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 228                                   ACPI_CAST_PTR(char, &target_name)));
 229                 return_ACPI_STATUS(AE_NOT_FOUND);
 230         }
 231
 232         if (acpi_ns_local(type)) {
 233                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 234                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 235                                   ACPI_CAST_PTR(char, &target_name),
 236                                   acpi_ut_get_type_name(type)));
 237                 return_ACPI_STATUS(AE_NOT_FOUND);
 238         }
 239
 240         /* Search the parent tree */
 241
 242         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 243                           "Searching parent [%4.4s] for [%4.4s]\n",
 244                           acpi_ut_get_node_name(parent_node),
 245                           ACPI_CAST_PTR(char, &target_name)));
 246
 247         /* Search parents until target is found or we have backed up to the root */
 248
 249         while (parent_node) {
 250                 /*
 251                  * Search parent scope. Use TYPE_ANY because we don't care about the
 252                  * object type at this point, we only care about the existence of
 253                  * the actual name we are searching for. Typechecking comes later.
 254                  */
 255                 status =
 256                     acpi_ns_search_one_scope(target_name, parent_node,
 257                                              ACPI_TYPE_ANY, return_node);
 258                 if (ACPI_SUCCESS(status)) {
 259                         return_ACPI_STATUS(status);
 260                 }
 261
 262                 /* Not found here, go up another level (until we reach the root) */
 263
 264                 parent_node = acpi_ns_get_parent_node(parent_node);
 265         }
 266
 267         /* Not found in parent tree */
 268
 269         return_ACPI_STATUS(AE_NOT_FOUND);
 270 }
 271
 272 /*******************************************************************************
 273  *
 274  * FUNCTION:    acpi_ns_search_and_enter
 275  *
 276  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 277  *              walk_state          - Current state of the walk
 278  *              Node                - Starting node where search will begin
 279  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 280  *                                    Otherwise,search only.
 281  *              Type                - Object type to match
 282  *              Flags               - Flags describing the search restrictions
 283  *              return_node         - Where the Node is returned
 284  *
 285  * RETURN:      Status
 286  *
 287  * DESCRIPTION: Search for a name segment in a single namespace level,
 288  *              optionally adding it if it is not found. If the passed
 289  *              Type is not Any and the type previously stored in the
 290  *              entry was Any (i.e. unknown), update the stored type.
 291  *
 292  *              In ACPI_IMODE_EXECUTE, search only.
 293  *              In other modes, search and add if not found.
 294  *
 295  ******************************************************************************/
 296
 297 acpi_status
 298 acpi_ns_search_and_enter(u32 target_name,
 299                          struct acpi_walk_state *walk_state,
 300                          struct acpi_namespace_node *node,
 301                          acpi_interpreter_mode interpreter_mode,
 302                          acpi_object_type type,
 303                          u32 flags, struct acpi_namespace_node **return_node)
 304 {
 305         acpi_status status;
 306         struct acpi_namespace_node *new_node;
 307
 308         ACPI_FUNCTION_TRACE(ns_search_and_enter);
 309
 310         /* Parameter validation */
 311
 312         if (!node || !target_name || !return_node) {
 313                 ACPI_ERROR((AE_INFO,
 314                             "Null parameter: Node %p Name %X ReturnNode %p",
 315                             node, target_name, return_node));
 316                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 317         }
 318
 319         /*
 320          * Name must consist of valid ACPI characters. We will repair the name if
 321          * necessary because we don't want to abort because of this, but we want
 322          * all namespace names to be printable. A warning message is appropriate.
 323          *
 324          * This issue came up because there are in fact machines that exhibit
 325          * this problem, and we want to be able to enable ACPI support for them,
 326          * even though there are a few bad names.
 327          */
 328         if (!acpi_ut_valid_acpi_name(target_name)) {
 329                 target_name =
 330                     acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
 331
 332                 /* Report warning only if in strict mode or debug mode */
 333
 334                 if (!acpi_gbl_enable_interpreter_slack) {
 335                         ACPI_WARNING((AE_INFO,
 336                                       "Found bad character(s) in name, repaired: [%4.4s]\n",
 337                                       ACPI_CAST_PTR(char, &target_name)));
 338                 } else {
 339                         ACPI_DEBUG_PRINT((ACPI_DB_INFO,
 340                                           "Found bad character(s) in name, repaired: [%4.4s]\n",
 341                                           ACPI_CAST_PTR(char, &target_name)));
 342                 }
 343         }
 344
 345         /* Try to find the name in the namespace level specified by the caller */
 346
 347         *return_node = ACPI_ENTRY_NOT_FOUND;
 348         status = acpi_ns_search_one_scope(target_name, node, type, return_node);
 349         if (status != AE_NOT_FOUND) {
 350                 /*
 351                  * If we found it AND the request specifies that a find is an error,
 352                  * return the error
 353                  */
 354                 if ((status == AE_OK) && (flags & ACPI_NS_ERROR_IF_FOUND)) {
 355                         status = AE_ALREADY_EXISTS;
 356                 }
 357
 358                 /* Either found it or there was an error: finished either way */
 359
 360                 return_ACPI_STATUS(status);
 361         }
 362
 363         /*
 364          * The name was not found. If we are NOT performing the first pass
 365          * (name entry) of loading the namespace, search the parent tree (all the
 366          * way to the root if necessary.) We don't want to perform the parent
 367          * search when the namespace is actually being loaded. We want to perform
 368          * the search when namespace references are being resolved (load pass 2)
 369          * and during the execution phase.
 370          */
 371         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 372             (flags & ACPI_NS_SEARCH_PARENT)) {
 373                 /*
 374                  * Not found at this level - search parent tree according to the
 375                  * ACPI specification
 376                  */
 377                 status =
 378                     acpi_ns_search_parent_tree(target_name, node, type,
 379                                                return_node);
 380                 if (ACPI_SUCCESS(status)) {
 381                         return_ACPI_STATUS(status);
 382                 }
 383         }
 384
 385         /* In execute mode, just search, never add names. Exit now */
 386
 387         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 388                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 389                                   "%4.4s Not found in %p [Not adding]\n",
 390                                   ACPI_CAST_PTR(char, &target_name), node));
 391
 392                 return_ACPI_STATUS(AE_NOT_FOUND);
 393         }
 394
 395         /* Create the new named object */
 396
 397         new_node = acpi_ns_create_node(target_name);
 398         if (!new_node) {
 399                 return_ACPI_STATUS(AE_NO_MEMORY);
 400         }
 401 #ifdef ACPI_ASL_COMPILER
 402
 403         /* Node is an object defined by an External() statement */
 404
 405         if (flags & ACPI_NS_EXTERNAL) {
 406                 new_node->flags |= ANOBJ_IS_EXTERNAL;
 407         }
 408 #endif
 409
 410         if (flags & ACPI_NS_TEMPORARY) {
 411                 new_node->flags |= ANOBJ_TEMPORARY;
 412         }
 413
 414         /* Install the new object into the parent's list of children */
 415
 416         acpi_ns_install_node(walk_state, node, new_node, type);
 417         *return_node = new_node;
 418         return_ACPI_STATUS(AE_OK);
 419 }