drivers/acpi/acpica/utownerid.c

   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 }