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%2.2X] 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 255) 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: %2.2X\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 (255 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%2.2X", 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 "Release of non-allocated OwnerId: 0x%2.2X", 183 owner_id + 1)); 184 } 185 186 (void)acpi_ut_release_mutex(ACPI_MTX_CACHES); 187 return_VOID; 188 } 189