drivers/acpi/acpica/nssearch.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: nssearch - Namespace search
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2015, 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                 /* Didn't match name, move on to the next peer object */
 156
 157                 node = node->peer;
 158         }
 159
 160         /* Searched entire namespace level, not found */
 161
 162         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 163                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] "
 164                           "%p first child %p\n",
 165                           ACPI_CAST_PTR(char, &target_name),
 166                           acpi_ut_get_type_name(type),
 167                           acpi_ut_get_node_name(parent_node), parent_node,
 168                           parent_node->child));
 169
 170         return_ACPI_STATUS(AE_NOT_FOUND);
 171 }
 172
 173 /*******************************************************************************
 174  *
 175  * FUNCTION:    acpi_ns_search_parent_tree
 176  *
 177  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 178  *              node            - Starting node where search will begin
 179  *              type            - Object type to match
 180  *              return_node     - Where the matched Node is returned
 181  *
 182  * RETURN:      Status
 183  *
 184  * DESCRIPTION: Called when a name has not been found in the current namespace
 185  *              level. Before adding it or giving up, ACPI scope rules require
 186  *              searching enclosing scopes in cases identified by acpi_ns_local().
 187  *
 188  *              "A name is located by finding the matching name in the current
 189  *              name space, and then in the parent name space. If the parent
 190  *              name space does not contain the name, the search continues
 191  *              recursively until either the name is found or the name space
 192  *              does not have a parent (the root of the name space). This
 193  *              indicates that the name is not found" (From ACPI Specification,
 194  *              section 5.3)
 195  *
 196  ******************************************************************************/
 197
 198 static acpi_status
 199 acpi_ns_search_parent_tree(u32 target_name,
 200                            struct acpi_namespace_node *node,
 201                            acpi_object_type type,
 202                            struct acpi_namespace_node **return_node)
 203 {
 204         acpi_status status;
 205         struct acpi_namespace_node *parent_node;
 206
 207         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 208
 209         parent_node = node->parent;
 210
 211         /*
 212          * If there is no parent (i.e., we are at the root) or type is "local",
 213          * we won't be searching the parent tree.
 214          */
 215         if (!parent_node) {
 216                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 217                                   ACPI_CAST_PTR(char, &target_name)));
 218                 return_ACPI_STATUS(AE_NOT_FOUND);
 219         }
 220
 221         if (acpi_ns_local(type)) {
 222                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 223                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 224                                   ACPI_CAST_PTR(char, &target_name),
 225                                   acpi_ut_get_type_name(type)));
 226                 return_ACPI_STATUS(AE_NOT_FOUND);
 227         }
 228
 229         /* Search the parent tree */
 230
 231         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 232                           "Searching parent [%4.4s] for [%4.4s]\n",
 233                           acpi_ut_get_node_name(parent_node),
 234                           ACPI_CAST_PTR(char, &target_name)));
 235
 236         /* Search parents until target is found or we have backed up to the root */
 237
 238         while (parent_node) {
 239                 /*
 240                  * Search parent scope. Use TYPE_ANY because we don't care about the
 241                  * object type at this point, we only care about the existence of
 242                  * the actual name we are searching for. Typechecking comes later.
 243                  */
 244                 status =
 245                     acpi_ns_search_one_scope(target_name, parent_node,
 246                                              ACPI_TYPE_ANY, return_node);
 247                 if (ACPI_SUCCESS(status)) {
 248                         return_ACPI_STATUS(status);
 249                 }
 250
 251                 /* Not found here, go up another level (until we reach the root) */
 252
 253                 parent_node = parent_node->parent;
 254         }
 255
 256         /* Not found in parent tree */
 257
 258         return_ACPI_STATUS(AE_NOT_FOUND);
 259 }
 260
 261 /*******************************************************************************
 262  *
 263  * FUNCTION:    acpi_ns_search_and_enter
 264  *
 265  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 266  *              walk_state          - Current state of the walk
 267  *              node                - Starting node where search will begin
 268  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 269  *                                    Otherwise,search only.
 270  *              type                - Object type to match
 271  *              flags               - Flags describing the search restrictions
 272  *              return_node         - Where the Node is returned
 273  *
 274  * RETURN:      Status
 275  *
 276  * DESCRIPTION: Search for a name segment in a single namespace level,
 277  *              optionally adding it if it is not found. If the passed
 278  *              Type is not Any and the type previously stored in the
 279  *              entry was Any (i.e. unknown), update the stored type.
 280  *
 281  *              In ACPI_IMODE_EXECUTE, search only.
 282  *              In other modes, search and add if not found.
 283  *
 284  ******************************************************************************/
 285
 286 acpi_status
 287 acpi_ns_search_and_enter(u32 target_name,
 288                          struct acpi_walk_state *walk_state,
 289                          struct acpi_namespace_node *node,
 290                          acpi_interpreter_mode interpreter_mode,
 291                          acpi_object_type type,
 292                          u32 flags, struct acpi_namespace_node **return_node)
 293 {
 294         acpi_status status;
 295         struct acpi_namespace_node *new_node;
 296
 297         ACPI_FUNCTION_TRACE(ns_search_and_enter);
 298
 299         /* Parameter validation */
 300
 301         if (!node || !target_name || !return_node) {
 302                 ACPI_ERROR((AE_INFO,
 303                             "Null parameter: Node %p Name 0x%X ReturnNode %p",
 304                             node, target_name, return_node));
 305                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 306         }
 307
 308         /*
 309          * Name must consist of valid ACPI characters. We will repair the name if
 310          * necessary because we don't want to abort because of this, but we want
 311          * all namespace names to be printable. A warning message is appropriate.
 312          *
 313          * This issue came up because there are in fact machines that exhibit
 314          * this problem, and we want to be able to enable ACPI support for them,
 315          * even though there are a few bad names.
 316          */
 317         acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
 318
 319         /* Try to find the name in the namespace level specified by the caller */
 320
 321         *return_node = ACPI_ENTRY_NOT_FOUND;
 322         status = acpi_ns_search_one_scope(target_name, node, type, return_node);
 323         if (status != AE_NOT_FOUND) {
 324                 /*
 325                  * If we found it AND the request specifies that a find is an error,
 326                  * return the error
 327                  */
 328                 if (status == AE_OK) {
 329
 330                         /* The node was found in the namespace */
 331
 332                         /*
 333                          * If the namespace override feature is enabled for this node,
 334                          * delete any existing attached sub-object and make the node
 335                          * look like a new node that is owned by the override table.
 336                          */
 337                         if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 338                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 339                                                   "Namespace override: %4.4s pass %u type %X Owner %X\n",
 340                                                   ACPI_CAST_PTR(char,
 341                                                                 &target_name),
 342                                                   interpreter_mode,
 343                                                   (*return_node)->type,
 344                                                   walk_state->owner_id));
 345
 346                                 acpi_ns_delete_children(*return_node);
 347                                 if (acpi_gbl_runtime_namespace_override) {
 348                                         acpi_ut_remove_reference((*return_node)->object);
 349                                         (*return_node)->object = NULL;
 350                                         (*return_node)->owner_id =
 351                                             walk_state->owner_id;
 352                                 } else {
 353                                         acpi_ns_remove_node(*return_node);
 354                                         *return_node = ACPI_ENTRY_NOT_FOUND;
 355                                 }
 356                         }
 357
 358                         /* Return an error if we don't expect to find the object */
 359
 360                         else if (flags & ACPI_NS_ERROR_IF_FOUND) {
 361                                 status = AE_ALREADY_EXISTS;
 362                         }
 363                 }
 364 #ifdef ACPI_ASL_COMPILER
 365                 if (*return_node && (*return_node)->type == ACPI_TYPE_ANY) {
 366                         (*return_node)->flags |= ANOBJ_IS_EXTERNAL;
 367                 }
 368 #endif
 369
 370                 /* Either found it or there was an error: finished either way */
 371
 372                 return_ACPI_STATUS(status);
 373         }
 374
 375         /*
 376          * The name was not found. If we are NOT performing the first pass
 377          * (name entry) of loading the namespace, search the parent tree (all the
 378          * way to the root if necessary.) We don't want to perform the parent
 379          * search when the namespace is actually being loaded. We want to perform
 380          * the search when namespace references are being resolved (load pass 2)
 381          * and during the execution phase.
 382          */
 383         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 384             (flags & ACPI_NS_SEARCH_PARENT)) {
 385                 /*
 386                  * Not found at this level - search parent tree according to the
 387                  * ACPI specification
 388                  */
 389                 status =
 390                     acpi_ns_search_parent_tree(target_name, node, type,
 391                                                return_node);
 392                 if (ACPI_SUCCESS(status)) {
 393                         return_ACPI_STATUS(status);
 394                 }
 395         }
 396
 397         /* In execute mode, just search, never add names. Exit now */
 398
 399         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 400                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 401                                   "%4.4s Not found in %p [Not adding]\n",
 402                                   ACPI_CAST_PTR(char, &target_name), node));
 403
 404                 return_ACPI_STATUS(AE_NOT_FOUND);
 405         }
 406
 407         /* Create the new named object */
 408
 409         new_node = acpi_ns_create_node(target_name);
 410         if (!new_node) {
 411                 return_ACPI_STATUS(AE_NO_MEMORY);
 412         }
 413 #ifdef ACPI_ASL_COMPILER
 414
 415         /* Node is an object defined by an External() statement */
 416
 417         if (flags & ACPI_NS_EXTERNAL ||
 418             (walk_state && walk_state->opcode == AML_SCOPE_OP)) {
 419                 new_node->flags |= ANOBJ_IS_EXTERNAL;
 420         }
 421 #endif
 422
 423         if (flags & ACPI_NS_TEMPORARY) {
 424                 new_node->flags |= ANOBJ_TEMPORARY;
 425         }
 426
 427         /* Install the new object into the parent's list of children */
 428
 429         acpi_ns_install_node(walk_state, node, new_node, type);
 430         *return_node = new_node;
 431         return_ACPI_STATUS(AE_OK);
 432 }