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
17ACPI_MODULE_NAME("nssearch")
18
19/* Local prototypes */
20static acpi_status
21acpi_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
58acpi_status
59acpi_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(node: 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
162static acpi_status
163acpi_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
250acpi_status
251acpi_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, parent_node: 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(parent: *return_node);
311 if (acpi_gbl_runtime_namespace_override) {
312 acpi_ut_remove_reference(object: (*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(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(name: 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, parent_node: node, node: new_node, type);
394 *return_node = new_node;
395 return_ACPI_STATUS(AE_OK);
396}
397