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1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.02/*******************************************************************************3 *4 * Module Name: utownerid - Support for Table/Method Owner IDs5 *6 ******************************************************************************/7 8#include <acpi/acpi.h>9#include "accommon.h"10#include "acnamesp.h"11 12#define _COMPONENT ACPI_UTILITIES13ACPI_MODULE_NAME("utownerid")14 15/*******************************************************************************16 *17 * FUNCTION: acpi_ut_allocate_owner_id18 *19 * PARAMETERS: owner_id - Where the new owner ID is returned20 *21 * RETURN: Status22 *23 * DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to24 * track objects created by the table or method, to be deleted25 * when the method exits or the table is unloaded.26 *27 ******************************************************************************/28acpi_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 repeated54 * allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index55 * 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 unsigned73 * integer. Omitting the cast may result in 1 being stored as an74 * int. Some compilers or runtime error detection may flag this as75 * 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 ID81 * 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 position90 *91 * Note: Last [j].k (bit 4095) is never used and is marked92 * 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 should109 * not happen since the IDs are reused after deallocation. The IDs are110 * allocated upon table load (one per table) and method execution, and111 * they are released when a table is unloaded or a method completes112 * execution.113 *114 * If this error happens, there may be very deep nesting of invoked115 * 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 121exit:122 (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);123 return_ACPI_STATUS(status);124}125 126/*******************************************************************************127 *128 * FUNCTION: acpi_ut_release_owner_id129 *130 * PARAMETERS: owner_id_ptr - Pointer to a previously allocated owner_ID131 *132 * RETURN: None. No error is returned because we are either exiting a133 * control method or unloading a table. Either way, we would134 * ignore any error anyway.135 *136 * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255137 *138 ******************************************************************************/139 140void 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}189