1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2 /*******************************************************************************
3 *
4 * Module Name: utownerid - Support for Table/Method Owner IDs
5 *
6 ******************************************************************************/
7
8 #include <acpi/acpi.h>
9 #include "accommon.h"
10 #include "acnamesp.h"
11
12 #define _COMPONENT ACPI_UTILITIES
13 ACPI_MODULE_NAME("utownerid")
14
15 /*******************************************************************************
16 *
17 * FUNCTION: acpi_ut_allocate_owner_id
18 *
19 * PARAMETERS: owner_id - Where the new owner ID is returned
20 *
21 * RETURN: Status
22 *
23 * DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to
24 * track objects created by the table or method, to be deleted
25 * when the method exits or the table is unloaded.
26 *
27 ******************************************************************************/
28 acpi_status acpi_ut_allocate_owner_id(acpi_owner_id *owner_id)
29 {
30 u32 i;
31 u32 j;
32 u32 k;
33 acpi_status status;
34
35 ACPI_FUNCTION_TRACE(ut_allocate_owner_id);
36
37 /* Guard against multiple allocations of ID to the same location */
38
39 if (*owner_id) {
40 ACPI_ERROR((AE_INFO,
41 "Owner ID [0x%3.3X] already exists", *owner_id));
42 return_ACPI_STATUS(AE_ALREADY_EXISTS);
43 }
44
45 /* Mutex for the global ID mask */
46
47 status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
48 if (ACPI_FAILURE(status)) {
49 return_ACPI_STATUS(status);
50 }
51
52 /*
53 * Find a free owner ID, cycle through all possible IDs on repeated
54 * allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index
55 * may have to be scanned twice.
56 */
57 for (i = 0, j = acpi_gbl_last_owner_id_index;
58 i < (ACPI_NUM_OWNERID_MASKS + 1); i++, j++) {
59 if (j >= ACPI_NUM_OWNERID_MASKS) {
60 j = 0; /* Wraparound to start of mask array */
61 }
62
63 for (k = acpi_gbl_next_owner_id_offset; k < 32; k++) {
64 if (acpi_gbl_owner_id_mask[j] == ACPI_UINT32_MAX) {
65
66 /* There are no free IDs in this mask */
67
68 break;
69 }
70
71 /*
72 * Note: the u32 cast ensures that 1 is stored as a unsigned
73 * integer. Omitting the cast may result in 1 being stored as an
74 * int. Some compilers or runtime error detection may flag this as
75 * an error.
76 */
77 if (!(acpi_gbl_owner_id_mask[j] & ((u32)1 << k))) {
78 /*
79 * Found a free ID. The actual ID is the bit index plus one,
80 * making zero an invalid Owner ID. Save this as the last ID
81 * allocated and update the global ID mask.
82 */
83 acpi_gbl_owner_id_mask[j] |= ((u32)1 << k);
84
85 acpi_gbl_last_owner_id_index = (u8)j;
86 acpi_gbl_next_owner_id_offset = (u8)(k + 1);
87
88 /*
89 * Construct encoded ID from the index and bit position
90 *
91 * Note: Last [j].k (bit 4095) is never used and is marked
92 * permanently allocated (prevents +1 overflow)
93 */
94 *owner_id =
95 (acpi_owner_id)((k + 1) + ACPI_MUL_32(j));
96
97 ACPI_DEBUG_PRINT((ACPI_DB_VALUES,
98 "Allocated OwnerId: 0x%3.3X\n",
99 (unsigned int)*owner_id));
100 goto exit;
101 }
102 }
103
104 acpi_gbl_next_owner_id_offset = 0;
105 }
106
107 /*
108 * All owner_ids have been allocated. This typically should
109 * not happen since the IDs are reused after deallocation. The IDs are
110 * allocated upon table load (one per table) and method execution, and
111 * they are released when a table is unloaded or a method completes
112 * execution.
113 *
114 * If this error happens, there may be very deep nesting of invoked
115 * control methods, or there may be a bug where the IDs are not released.
116 */
117 status = AE_OWNER_ID_LIMIT;
118 ACPI_ERROR((AE_INFO,
119 "Could not allocate new OwnerId (4095 max), AE_OWNER_ID_LIMIT"));
120
121 exit:
122 (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
123 return_ACPI_STATUS(status);
124 }
125
126 /*******************************************************************************
127 *
128 * FUNCTION: acpi_ut_release_owner_id
129 *
130 * PARAMETERS: owner_id_ptr - Pointer to a previously allocated owner_ID
131 *
132 * RETURN: None. No error is returned because we are either exiting a
133 * control method or unloading a table. Either way, we would
134 * ignore any error anyway.
135 *
136 * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255
137 *
138 ******************************************************************************/
139
140 void acpi_ut_release_owner_id(acpi_owner_id *owner_id_ptr)
141 {
142 acpi_owner_id owner_id = *owner_id_ptr;
143 acpi_status status;
144 u32 index;
145 u32 bit;
146
147 ACPI_FUNCTION_TRACE_U32(ut_release_owner_id, owner_id);
148
149 /* Always clear the input owner_id (zero is an invalid ID) */
150
151 *owner_id_ptr = 0;
152
153 /* Zero is not a valid owner_ID */
154
155 if (owner_id == 0) {
156 ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%3.3X", owner_id));
157 return_VOID;
158 }
159
160 /* Mutex for the global ID mask */
161
162 status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
163 if (ACPI_FAILURE(status)) {
164 return_VOID;
165 }
166
167 /* Normalize the ID to zero */
168
169 owner_id--;
170
171 /* Decode ID to index/offset pair */
172
173 index = ACPI_DIV_32(owner_id);
174 bit = (u32)1 << ACPI_MOD_32(owner_id);
175
176 /* Free the owner ID only if it is valid */
177
178 if (acpi_gbl_owner_id_mask[index] & bit) {
179 acpi_gbl_owner_id_mask[index] ^= bit;
180 } else {
181 ACPI_ERROR((AE_INFO,
182 "Attempted release of non-allocated OwnerId: 0x%3.3X",
183 owner_id + 1));
184 }
185
186 (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
187 return_VOID;
188 }