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
acpi_ns_search_one_scope(u32 target_name,struct acpi_namespace_node * parent_node,acpi_object_type type,struct acpi_namespace_node ** return_node)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
acpi_ns_search_parent_tree(u32 target_name,struct acpi_namespace_node * node,acpi_object_type type,struct acpi_namespace_node ** return_node)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
acpi_ns_search_and_enter(u32 target_name,struct acpi_walk_state * walk_state,struct acpi_namespace_node * node,acpi_interpreter_mode interpreter_mode,acpi_object_type type,u32 flags,struct acpi_namespace_node ** return_node)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 }
397