Bob Moore | 42f8fb7 | 2013-01-11 13:08:51 +0100 | [diff] [blame^] | 1 | /******************************************************************************* |
| 2 | * |
| 3 | * Module Name: utownerid - Support for Table/Method Owner IDs |
| 4 | * |
| 5 | ******************************************************************************/ |
| 6 | |
| 7 | /* |
| 8 | * Copyright (C) 2000 - 2012, 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, "Owner ID [0x%2.2X] already exists", |
| 77 | *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 may have |
| 91 | * 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 | if (!(acpi_gbl_owner_id_mask[j] & (1 << k))) { |
| 108 | /* |
| 109 | * Found a free ID. The actual ID is the bit index plus one, |
| 110 | * making zero an invalid Owner ID. Save this as the last ID |
| 111 | * allocated and update the global ID mask. |
| 112 | */ |
| 113 | acpi_gbl_owner_id_mask[j] |= (1 << k); |
| 114 | |
| 115 | acpi_gbl_last_owner_id_index = (u8)j; |
| 116 | acpi_gbl_next_owner_id_offset = (u8)(k + 1); |
| 117 | |
| 118 | /* |
| 119 | * Construct encoded ID from the index and bit position |
| 120 | * |
| 121 | * Note: Last [j].k (bit 255) is never used and is marked |
| 122 | * permanently allocated (prevents +1 overflow) |
| 123 | */ |
| 124 | *owner_id = |
| 125 | (acpi_owner_id) ((k + 1) + ACPI_MUL_32(j)); |
| 126 | |
| 127 | ACPI_DEBUG_PRINT((ACPI_DB_VALUES, |
| 128 | "Allocated OwnerId: %2.2X\n", |
| 129 | (unsigned int)*owner_id)); |
| 130 | goto exit; |
| 131 | } |
| 132 | } |
| 133 | |
| 134 | acpi_gbl_next_owner_id_offset = 0; |
| 135 | } |
| 136 | |
| 137 | /* |
| 138 | * All owner_ids have been allocated. This typically should |
| 139 | * not happen since the IDs are reused after deallocation. The IDs are |
| 140 | * allocated upon table load (one per table) and method execution, and |
| 141 | * they are released when a table is unloaded or a method completes |
| 142 | * execution. |
| 143 | * |
| 144 | * If this error happens, there may be very deep nesting of invoked control |
| 145 | * methods, or there may be a bug where the IDs are not released. |
| 146 | */ |
| 147 | status = AE_OWNER_ID_LIMIT; |
| 148 | ACPI_ERROR((AE_INFO, |
| 149 | "Could not allocate new OwnerId (255 max), AE_OWNER_ID_LIMIT")); |
| 150 | |
| 151 | exit: |
| 152 | (void)acpi_ut_release_mutex(ACPI_MTX_CACHES); |
| 153 | return_ACPI_STATUS(status); |
| 154 | } |
| 155 | |
| 156 | /******************************************************************************* |
| 157 | * |
| 158 | * FUNCTION: acpi_ut_release_owner_id |
| 159 | * |
| 160 | * PARAMETERS: owner_id_ptr - Pointer to a previously allocated owner_ID |
| 161 | * |
| 162 | * RETURN: None. No error is returned because we are either exiting a |
| 163 | * control method or unloading a table. Either way, we would |
| 164 | * ignore any error anyway. |
| 165 | * |
| 166 | * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255 |
| 167 | * |
| 168 | ******************************************************************************/ |
| 169 | |
| 170 | void acpi_ut_release_owner_id(acpi_owner_id * owner_id_ptr) |
| 171 | { |
| 172 | acpi_owner_id owner_id = *owner_id_ptr; |
| 173 | acpi_status status; |
| 174 | u32 index; |
| 175 | u32 bit; |
| 176 | |
| 177 | ACPI_FUNCTION_TRACE_U32(ut_release_owner_id, owner_id); |
| 178 | |
| 179 | /* Always clear the input owner_id (zero is an invalid ID) */ |
| 180 | |
| 181 | *owner_id_ptr = 0; |
| 182 | |
| 183 | /* Zero is not a valid owner_ID */ |
| 184 | |
| 185 | if (owner_id == 0) { |
| 186 | ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%2.2X", owner_id)); |
| 187 | return_VOID; |
| 188 | } |
| 189 | |
| 190 | /* Mutex for the global ID mask */ |
| 191 | |
| 192 | status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES); |
| 193 | if (ACPI_FAILURE(status)) { |
| 194 | return_VOID; |
| 195 | } |
| 196 | |
| 197 | /* Normalize the ID to zero */ |
| 198 | |
| 199 | owner_id--; |
| 200 | |
| 201 | /* Decode ID to index/offset pair */ |
| 202 | |
| 203 | index = ACPI_DIV_32(owner_id); |
| 204 | bit = 1 << ACPI_MOD_32(owner_id); |
| 205 | |
| 206 | /* Free the owner ID only if it is valid */ |
| 207 | |
| 208 | if (acpi_gbl_owner_id_mask[index] & bit) { |
| 209 | acpi_gbl_owner_id_mask[index] ^= bit; |
| 210 | } else { |
| 211 | ACPI_ERROR((AE_INFO, |
| 212 | "Release of non-allocated OwnerId: 0x%2.2X", |
| 213 | owner_id + 1)); |
| 214 | } |
| 215 | |
| 216 | (void)acpi_ut_release_mutex(ACPI_MTX_CACHES); |
| 217 | return_VOID; |
| 218 | } |