drivers/acpi/acpica/nssearch.c

   1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
   2 /*******************************************************************************
   3  *
   4  * Module Name: nssearch - Namespace search
   5  *
   6  ******************************************************************************/
   7
   8 #include <acpi/acpi.h>
   9 #include "accommon.h"
  10 #include "acnamesp.h"
  11
  12 #ifdef ACPI_ASL_COMPILER
  13 #include "amlcode.h"
  14 #endif
  15
  16 #define _COMPONENT          ACPI_NAMESPACE
  17 ACPI_MODULE_NAME("nssearch")
  18
  19 /* Local prototypes */
  20 static acpi_status
  21 acpi_ns_search_parent_tree(u32 target_name,
  22                            struct acpi_namespace_node *node,
  23                            acpi_object_type type,
  24                            struct acpi_namespace_node **return_node);
  25
  26 /*******************************************************************************
  27  *
  28  * FUNCTION:    acpi_ns_search_one_scope
  29  *
  30  * PARAMETERS:  target_name     - Ascii ACPI name to search for
  31  *              parent_node     - Starting node where search will begin
  32  *              type            - Object type to match
  33  *              return_node     - Where the matched Named obj is returned
  34  *
  35  * RETURN:      Status
  36  *
  37  * DESCRIPTION: Search a single level of the namespace. Performs a
  38  *              simple search of the specified level, and does not add
  39  *              entries or search parents.
  40  *
  41  *
  42  *      Named object lists are built (and subsequently dumped) in the
  43  *      order in which the names are encountered during the namespace load;
  44  *
  45  *      All namespace searching is linear in this implementation, but
  46  *      could be easily modified to support any improved search
  47  *      algorithm. However, the linear search was chosen for simplicity
  48  *      and because the trees are small and the other interpreter
  49  *      execution overhead is relatively high.
  50  *
  51  *      Note: CPU execution analysis has shown that the AML interpreter spends
  52  *      a very small percentage of its time searching the namespace. Therefore,
  53  *      the linear search seems to be sufficient, as there would seem to be
  54  *      little value in improving the search.
  55  *
  56  ******************************************************************************/
  57
  58 acpi_status
  59 acpi_ns_search_one_scope(u32 target_name,
  60                          struct acpi_namespace_node *parent_node,
  61                          acpi_object_type type,
  62                          struct acpi_namespace_node **return_node)
  63 {
  64         struct acpi_namespace_node *node;
  65
  66         ACPI_FUNCTION_TRACE(ns_search_one_scope);
  67
  68 #ifdef ACPI_DEBUG_OUTPUT
  69         if (ACPI_LV_NAMES & acpi_dbg_level) {
  70                 char *scope_name;
  71
  72                 scope_name = acpi_ns_get_normalized_pathname(parent_node, TRUE);
  73                 if (scope_name) {
  74                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
  75                                           "Searching %s (%p) For [%4.4s] (%s)\n",
  76                                           scope_name, parent_node,
  77                                           ACPI_CAST_PTR(char, &target_name),
  78                                           acpi_ut_get_type_name(type)));
  79
  80                         ACPI_FREE(scope_name);
  81                 }
  82         }
  83 #endif
  84
  85         /*
  86          * Search for name at this namespace level, which is to say that we
  87          * must search for the name among the children of this object
  88          */
  89         node = parent_node->child;
  90         while (node) {
  91
  92                 /* Check for match against the name */
  93
  94                 if (node->name.integer == target_name) {
  95
  96                         /* Resolve a control method alias if any */
  97
  98                         if (acpi_ns_get_type(node) ==
  99                             ACPI_TYPE_LOCAL_METHOD_ALIAS) {
 100                                 node =
 101                                     ACPI_CAST_PTR(struct acpi_namespace_node,
 102                                                   node->object);
 103                         }
 104
 105                         /* Found matching entry */
 106
 107                         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 108                                           "Name [%4.4s] (%s) %p found in scope [%4.4s] %p\n",
 109                                           ACPI_CAST_PTR(char, &target_name),
 110                                           acpi_ut_get_type_name(node->type),
 111                                           node,
 112                                           acpi_ut_get_node_name(parent_node),
 113                                           parent_node));
 114
 115                         *return_node = node;
 116                         return_ACPI_STATUS(AE_OK);
 117                 }
 118
 119                 /* Didn't match name, move on to the next peer object */
 120
 121                 node = node->peer;
 122         }
 123
 124         /* Searched entire namespace level, not found */
 125
 126         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 127                           "Name [%4.4s] (%s) not found in search in scope [%4.4s] "
 128                           "%p first child %p\n",
 129                           ACPI_CAST_PTR(char, &target_name),
 130                           acpi_ut_get_type_name(type),
 131                           acpi_ut_get_node_name(parent_node), parent_node,
 132                           parent_node->child));
 133
 134         return_ACPI_STATUS(AE_NOT_FOUND);
 135 }
 136
 137 /*******************************************************************************
 138  *
 139  * FUNCTION:    acpi_ns_search_parent_tree
 140  *
 141  * PARAMETERS:  target_name     - Ascii ACPI name to search for
 142  *              node            - Starting node where search will begin
 143  *              type            - Object type to match
 144  *              return_node     - Where the matched Node is returned
 145  *
 146  * RETURN:      Status
 147  *
 148  * DESCRIPTION: Called when a name has not been found in the current namespace
 149  *              level. Before adding it or giving up, ACPI scope rules require
 150  *              searching enclosing scopes in cases identified by acpi_ns_local().
 151  *
 152  *              "A name is located by finding the matching name in the current
 153  *              name space, and then in the parent name space. If the parent
 154  *              name space does not contain the name, the search continues
 155  *              recursively until either the name is found or the name space
 156  *              does not have a parent (the root of the name space). This
 157  *              indicates that the name is not found" (From ACPI Specification,
 158  *              section 5.3)
 159  *
 160  ******************************************************************************/
 161
 162 static acpi_status
 163 acpi_ns_search_parent_tree(u32 target_name,
 164                            struct acpi_namespace_node *node,
 165                            acpi_object_type type,
 166                            struct acpi_namespace_node **return_node)
 167 {
 168         acpi_status status;
 169         struct acpi_namespace_node *parent_node;
 170
 171         ACPI_FUNCTION_TRACE(ns_search_parent_tree);
 172
 173         parent_node = node->parent;
 174
 175         /*
 176          * If there is no parent (i.e., we are at the root) or type is "local",
 177          * we won't be searching the parent tree.
 178          */
 179         if (!parent_node) {
 180                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES, "[%4.4s] has no parent\n",
 181                                   ACPI_CAST_PTR(char, &target_name)));
 182                 return_ACPI_STATUS(AE_NOT_FOUND);
 183         }
 184
 185         if (acpi_ns_local(type)) {
 186                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 187                                   "[%4.4s] type [%s] must be local to this scope (no parent search)\n",
 188                                   ACPI_CAST_PTR(char, &target_name),
 189                                   acpi_ut_get_type_name(type)));
 190                 return_ACPI_STATUS(AE_NOT_FOUND);
 191         }
 192
 193         /* Search the parent tree */
 194
 195         ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 196                           "Searching parent [%4.4s] for [%4.4s]\n",
 197                           acpi_ut_get_node_name(parent_node),
 198                           ACPI_CAST_PTR(char, &target_name)));
 199
 200         /* Search parents until target is found or we have backed up to the root */
 201
 202         while (parent_node) {
 203                 /*
 204                  * Search parent scope. Use TYPE_ANY because we don't care about the
 205                  * object type at this point, we only care about the existence of
 206                  * the actual name we are searching for. Typechecking comes later.
 207                  */
 208                 status =
 209                     acpi_ns_search_one_scope(target_name, parent_node,
 210                                              ACPI_TYPE_ANY, return_node);
 211                 if (ACPI_SUCCESS(status)) {
 212                         return_ACPI_STATUS(status);
 213                 }
 214
 215                 /* Not found here, go up another level (until we reach the root) */
 216
 217                 parent_node = parent_node->parent;
 218         }
 219
 220         /* Not found in parent tree */
 221
 222         return_ACPI_STATUS(AE_NOT_FOUND);
 223 }
 224
 225 /*******************************************************************************
 226  *
 227  * FUNCTION:    acpi_ns_search_and_enter
 228  *
 229  * PARAMETERS:  target_name         - Ascii ACPI name to search for (4 chars)
 230  *              walk_state          - Current state of the walk
 231  *              node                - Starting node where search will begin
 232  *              interpreter_mode    - Add names only in ACPI_MODE_LOAD_PASS_x.
 233  *                                    Otherwise,search only.
 234  *              type                - Object type to match
 235  *              flags               - Flags describing the search restrictions
 236  *              return_node         - Where the Node is returned
 237  *
 238  * RETURN:      Status
 239  *
 240  * DESCRIPTION: Search for a name segment in a single namespace level,
 241  *              optionally adding it if it is not found. If the passed
 242  *              Type is not Any and the type previously stored in the
 243  *              entry was Any (i.e. unknown), update the stored type.
 244  *
 245  *              In ACPI_IMODE_EXECUTE, search only.
 246  *              In other modes, search and add if not found.
 247  *
 248  ******************************************************************************/
 249
 250 acpi_status
 251 acpi_ns_search_and_enter(u32 target_name,
 252                          struct acpi_walk_state *walk_state,
 253                          struct acpi_namespace_node *node,
 254                          acpi_interpreter_mode interpreter_mode,
 255                          acpi_object_type type,
 256                          u32 flags, struct acpi_namespace_node **return_node)
 257 {
 258         acpi_status status;
 259         struct acpi_namespace_node *new_node;
 260
 261         ACPI_FUNCTION_TRACE(ns_search_and_enter);
 262
 263         /* Parameter validation */
 264
 265         if (!node || !target_name || !return_node) {
 266                 ACPI_ERROR((AE_INFO,
 267                             "Null parameter: Node %p Name 0x%X ReturnNode %p",
 268                             node, target_name, return_node));
 269                 return_ACPI_STATUS(AE_BAD_PARAMETER);
 270         }
 271
 272         /*
 273          * Name must consist of valid ACPI characters. We will repair the name if
 274          * necessary because we don't want to abort because of this, but we want
 275          * all namespace names to be printable. A warning message is appropriate.
 276          *
 277          * This issue came up because there are in fact machines that exhibit
 278          * this problem, and we want to be able to enable ACPI support for them,
 279          * even though there are a few bad names.
 280          */
 281         acpi_ut_repair_name(ACPI_CAST_PTR(char, &target_name));
 282
 283         /* Try to find the name in the namespace level specified by the caller */
 284
 285         *return_node = ACPI_ENTRY_NOT_FOUND;
 286         status = acpi_ns_search_one_scope(target_name, node, type, return_node);
 287         if (status != AE_NOT_FOUND) {
 288                 /*
 289                  * If we found it AND the request specifies that a find is an error,
 290                  * return the error
 291                  */
 292                 if (status == AE_OK) {
 293
 294                         /* The node was found in the namespace */
 295
 296                         /*
 297                          * If the namespace override feature is enabled for this node,
 298                          * delete any existing attached sub-object and make the node
 299                          * look like a new node that is owned by the override table.
 300                          */
 301                         if (flags & ACPI_NS_OVERRIDE_IF_FOUND) {
 302                                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 303                                                   "Namespace override: %4.4s pass %u type %X Owner %X\n",
 304                                                   ACPI_CAST_PTR(char,
 305                                                                 &target_name),
 306                                                   interpreter_mode,
 307                                                   (*return_node)->type,
 308                                                   walk_state->owner_id));
 309
 310                                 acpi_ns_delete_children(*return_node);
 311                                 if (acpi_gbl_runtime_namespace_override) {
 312                                         acpi_ut_remove_reference((*return_node)->object);
 313                                         (*return_node)->object = NULL;
 314                                         (*return_node)->owner_id =
 315                                             walk_state->owner_id;
 316                                 } else {
 317                                         acpi_ns_remove_node(*return_node);
 318                                         *return_node = ACPI_ENTRY_NOT_FOUND;
 319                                 }
 320                         }
 321
 322                         /* Return an error if we don't expect to find the object */
 323
 324                         else if (flags & ACPI_NS_ERROR_IF_FOUND) {
 325                                 status = AE_ALREADY_EXISTS;
 326                         }
 327                 }
 328 #ifdef ACPI_ASL_COMPILER
 329                 if (*return_node && (*return_node)->type == ACPI_TYPE_ANY) {
 330                         (*return_node)->flags |= ANOBJ_IS_EXTERNAL;
 331                 }
 332 #endif
 333
 334                 /* Either found it or there was an error: finished either way */
 335
 336                 return_ACPI_STATUS(status);
 337         }
 338
 339         /*
 340          * The name was not found. If we are NOT performing the first pass
 341          * (name entry) of loading the namespace, search the parent tree (all the
 342          * way to the root if necessary.) We don't want to perform the parent
 343          * search when the namespace is actually being loaded. We want to perform
 344          * the search when namespace references are being resolved (load pass 2)
 345          * and during the execution phase.
 346          */
 347         if ((interpreter_mode != ACPI_IMODE_LOAD_PASS1) &&
 348             (flags & ACPI_NS_SEARCH_PARENT)) {
 349                 /*
 350                  * Not found at this level - search parent tree according to the
 351                  * ACPI specification
 352                  */
 353                 status =
 354                     acpi_ns_search_parent_tree(target_name, node, type,
 355                                                return_node);
 356                 if (ACPI_SUCCESS(status)) {
 357                         return_ACPI_STATUS(status);
 358                 }
 359         }
 360
 361         /* In execute mode, just search, never add names. Exit now */
 362
 363         if (interpreter_mode == ACPI_IMODE_EXECUTE) {
 364                 ACPI_DEBUG_PRINT((ACPI_DB_NAMES,
 365                                   "%4.4s Not found in %p [Not adding]\n",
 366                                   ACPI_CAST_PTR(char, &target_name), node));
 367
 368                 return_ACPI_STATUS(AE_NOT_FOUND);
 369         }
 370
 371         /* Create the new named object */
 372
 373         new_node = acpi_ns_create_node(target_name);
 374         if (!new_node) {
 375                 return_ACPI_STATUS(AE_NO_MEMORY);
 376         }
 377 #ifdef ACPI_ASL_COMPILER
 378
 379         /* Node is an object defined by an External() statement */
 380
 381         if (flags & ACPI_NS_EXTERNAL ||
 382             (walk_state && walk_state->opcode == AML_SCOPE_OP)) {
 383                 new_node->flags |= ANOBJ_IS_EXTERNAL;
 384         }
 385 #endif
 386
 387         if (flags & ACPI_NS_TEMPORARY) {
 388                 new_node->flags |= ANOBJ_TEMPORARY;
 389         }
 390
 391         /* Install the new object into the parent's list of children */
 392
 393         acpi_ns_install_node(walk_state, node, new_node, type);
 394         *return_node = new_node;
 395         return_ACPI_STATUS(AE_OK);
 396 }