1 /******************************************************************************* 2 * 3 * Module Name: utownerid - Support for Table/Method Owner IDs 4 * 5 ******************************************************************************/ 6 7 /* 8 * Copyright (C) 2000 - 2018, 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