xref: /openbmc/linux/drivers/acpi/acpica/utownerid.c (revision 5d0e4d78)
1 /*******************************************************************************
2  *
3  * Module Name: utownerid - Support for Table/Method Owner IDs
4  *
5  ******************************************************************************/
6 
7 /*
8  * Copyright (C) 2000 - 2017, 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 #define _COMPONENT          ACPI_UTILITIES
49 ACPI_MODULE_NAME("utownerid")
50 
51 /*******************************************************************************
52  *
53  * FUNCTION:    acpi_ut_allocate_owner_id
54  *
55  * PARAMETERS:  owner_id        - Where the new owner ID is returned
56  *
57  * RETURN:      Status
58  *
59  * DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to
60  *              track objects created by the table or method, to be deleted
61  *              when the method exits or the table is unloaded.
62  *
63  ******************************************************************************/
64 acpi_status acpi_ut_allocate_owner_id(acpi_owner_id *owner_id)
65 {
66 	u32 i;
67 	u32 j;
68 	u32 k;
69 	acpi_status status;
70 
71 	ACPI_FUNCTION_TRACE(ut_allocate_owner_id);
72 
73 	/* Guard against multiple allocations of ID to the same location */
74 
75 	if (*owner_id) {
76 		ACPI_ERROR((AE_INFO,
77 			    "Owner ID [0x%2.2X] already exists", *owner_id));
78 		return_ACPI_STATUS(AE_ALREADY_EXISTS);
79 	}
80 
81 	/* Mutex for the global ID mask */
82 
83 	status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
84 	if (ACPI_FAILURE(status)) {
85 		return_ACPI_STATUS(status);
86 	}
87 
88 	/*
89 	 * Find a free owner ID, cycle through all possible IDs on repeated
90 	 * allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index
91 	 * may have to be scanned twice.
92 	 */
93 	for (i = 0, j = acpi_gbl_last_owner_id_index;
94 	     i < (ACPI_NUM_OWNERID_MASKS + 1); i++, j++) {
95 		if (j >= ACPI_NUM_OWNERID_MASKS) {
96 			j = 0;	/* Wraparound to start of mask array */
97 		}
98 
99 		for (k = acpi_gbl_next_owner_id_offset; k < 32; k++) {
100 			if (acpi_gbl_owner_id_mask[j] == ACPI_UINT32_MAX) {
101 
102 				/* There are no free IDs in this mask */
103 
104 				break;
105 			}
106 
107 			/*
108 			 * Note: the u32 cast ensures that 1 is stored as a unsigned
109 			 * integer. Omitting the cast may result in 1 being stored as an
110 			 * int. Some compilers or runtime error detection may flag this as
111 			 * an error.
112 			 */
113 			if (!(acpi_gbl_owner_id_mask[j] & ((u32)1 << k))) {
114 				/*
115 				 * Found a free ID. The actual ID is the bit index plus one,
116 				 * making zero an invalid Owner ID. Save this as the last ID
117 				 * allocated and update the global ID mask.
118 				 */
119 				acpi_gbl_owner_id_mask[j] |= ((u32)1 << k);
120 
121 				acpi_gbl_last_owner_id_index = (u8)j;
122 				acpi_gbl_next_owner_id_offset = (u8)(k + 1);
123 
124 				/*
125 				 * Construct encoded ID from the index and bit position
126 				 *
127 				 * Note: Last [j].k (bit 255) is never used and is marked
128 				 * permanently allocated (prevents +1 overflow)
129 				 */
130 				*owner_id =
131 				    (acpi_owner_id)((k + 1) + ACPI_MUL_32(j));
132 
133 				ACPI_DEBUG_PRINT((ACPI_DB_VALUES,
134 						  "Allocated OwnerId: %2.2X\n",
135 						  (unsigned int)*owner_id));
136 				goto exit;
137 			}
138 		}
139 
140 		acpi_gbl_next_owner_id_offset = 0;
141 	}
142 
143 	/*
144 	 * All owner_ids have been allocated. This typically should
145 	 * not happen since the IDs are reused after deallocation. The IDs are
146 	 * allocated upon table load (one per table) and method execution, and
147 	 * they are released when a table is unloaded or a method completes
148 	 * execution.
149 	 *
150 	 * If this error happens, there may be very deep nesting of invoked
151 	 * control methods, or there may be a bug where the IDs are not released.
152 	 */
153 	status = AE_OWNER_ID_LIMIT;
154 	ACPI_ERROR((AE_INFO,
155 		    "Could not allocate new OwnerId (255 max), AE_OWNER_ID_LIMIT"));
156 
157 exit:
158 	(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
159 	return_ACPI_STATUS(status);
160 }
161 
162 /*******************************************************************************
163  *
164  * FUNCTION:    acpi_ut_release_owner_id
165  *
166  * PARAMETERS:  owner_id_ptr        - Pointer to a previously allocated owner_ID
167  *
168  * RETURN:      None. No error is returned because we are either exiting a
169  *              control method or unloading a table. Either way, we would
170  *              ignore any error anyway.
171  *
172  * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255
173  *
174  ******************************************************************************/
175 
176 void acpi_ut_release_owner_id(acpi_owner_id *owner_id_ptr)
177 {
178 	acpi_owner_id owner_id = *owner_id_ptr;
179 	acpi_status status;
180 	u32 index;
181 	u32 bit;
182 
183 	ACPI_FUNCTION_TRACE_U32(ut_release_owner_id, owner_id);
184 
185 	/* Always clear the input owner_id (zero is an invalid ID) */
186 
187 	*owner_id_ptr = 0;
188 
189 	/* Zero is not a valid owner_ID */
190 
191 	if (owner_id == 0) {
192 		ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%2.2X", owner_id));
193 		return_VOID;
194 	}
195 
196 	/* Mutex for the global ID mask */
197 
198 	status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
199 	if (ACPI_FAILURE(status)) {
200 		return_VOID;
201 	}
202 
203 	/* Normalize the ID to zero */
204 
205 	owner_id--;
206 
207 	/* Decode ID to index/offset pair */
208 
209 	index = ACPI_DIV_32(owner_id);
210 	bit = (u32)1 << ACPI_MOD_32(owner_id);
211 
212 	/* Free the owner ID only if it is valid */
213 
214 	if (acpi_gbl_owner_id_mask[index] & bit) {
215 		acpi_gbl_owner_id_mask[index] ^= bit;
216 	} else {
217 		ACPI_ERROR((AE_INFO,
218 			    "Release of non-allocated OwnerId: 0x%2.2X",
219 			    owner_id + 1));
220 	}
221 
222 	(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
223 	return_VOID;
224 }
225