drivers/bus/acpi/acpica/utilities/utownerid.c

   1 /*******************************************************************************
   2  *
   3  * Module Name: utownerid - Support for Table/Method Owner IDs
   4  *
   5  ******************************************************************************/
   6
   7 /*
   8  * Copyright (C) 2000 - 2017, 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.h"
  45 #include "accommon.h"
  46 #include "acnamesp.h"
  47
  48
  49 #define _COMPONENT          ACPI_UTILITIES
  50         ACPI_MODULE_NAME    ("utownerid")
  51
  52
  53 /*******************************************************************************
  54  *
  55  * FUNCTION:    AcpiUtAllocateOwnerId
  56  *
  57  * PARAMETERS:  OwnerId         - Where the new owner ID is returned
  58  *
  59  * RETURN:      Status
  60  *
  61  * DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to
  62  *              track objects created by the table or method, to be deleted
  63  *              when the method exits or the table is unloaded.
  64  *
  65  ******************************************************************************/
  66
  67 ACPI_STATUS
  68 AcpiUtAllocateOwnerId (
  69     ACPI_OWNER_ID           *OwnerId)
  70 {
  71     UINT32                  i;
  72     UINT32                  j;
  73     UINT32                  k;
  74     ACPI_STATUS             Status;
  75
  76
  77     ACPI_FUNCTION_TRACE (UtAllocateOwnerId);
  78
  79
  80     /* Guard against multiple allocations of ID to the same location */
  81
  82     if (*OwnerId)
  83     {
  84         ACPI_ERROR ((AE_INFO,
  85             "Owner ID [0x%2.2X] already exists", *OwnerId));
  86         return_ACPI_STATUS (AE_ALREADY_EXISTS);
  87     }
  88
  89     /* Mutex for the global ID mask */
  90
  91     Status = AcpiUtAcquireMutex (ACPI_MTX_CACHES);
  92     if (ACPI_FAILURE (Status))
  93     {
  94         return_ACPI_STATUS (Status);
  95     }
  96
  97     /*
  98      * Find a free owner ID, cycle through all possible IDs on repeated
  99      * allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index
 100      * may have to be scanned twice.
 101      */
 102     for (i = 0, j = AcpiGbl_LastOwnerIdIndex;
 103          i < (ACPI_NUM_OWNERID_MASKS + 1);
 104          i++, j++)
 105     {
 106         if (j >= ACPI_NUM_OWNERID_MASKS)
 107         {
 108             j = 0;  /* Wraparound to start of mask array */
 109         }
 110
 111         for (k = AcpiGbl_NextOwnerIdOffset; k < 32; k++)
 112         {
 113             if (AcpiGbl_OwnerIdMask[j] == ACPI_UINT32_MAX)
 114             {
 115                 /* There are no free IDs in this mask */
 116
 117                 break;
 118             }
 119
 120             /*
 121              * Note: the UINT32 cast ensures that 1 is stored as a unsigned
 122              * integer. Omitting the cast may result in 1 being stored as an
 123              * int. Some compilers or runtime error detection may flag this as
 124              * an error.
 125              */
 126             if (!(AcpiGbl_OwnerIdMask[j] & ((UINT32) 1 << k)))
 127             {
 128                 /*
 129                  * Found a free ID. The actual ID is the bit index plus one,
 130                  * making zero an invalid Owner ID. Save this as the last ID
 131                  * allocated and update the global ID mask.
 132                  */
 133                 AcpiGbl_OwnerIdMask[j] |= ((UINT32) 1 << k);
 134
 135                 AcpiGbl_LastOwnerIdIndex = (UINT8) j;
 136                 AcpiGbl_NextOwnerIdOffset = (UINT8) (k + 1);
 137
 138                 /*
 139                  * Construct encoded ID from the index and bit position
 140                  *
 141                  * Note: Last [j].k (bit 255) is never used and is marked
 142                  * permanently allocated (prevents +1 overflow)
 143                  */
 144                 *OwnerId = (ACPI_OWNER_ID) ((k + 1) + ACPI_MUL_32 (j));
 145
 146                 ACPI_DEBUG_PRINT ((ACPI_DB_VALUES,
 147                     "Allocated OwnerId: %2.2X\n", (unsigned int) *OwnerId));
 148                 goto Exit;
 149             }
 150         }
 151
 152         AcpiGbl_NextOwnerIdOffset = 0;
 153     }
 154
 155     /*
 156      * All OwnerIds have been allocated. This typically should
 157      * not happen since the IDs are reused after deallocation. The IDs are
 158      * allocated upon table load (one per table) and method execution, and
 159      * they are released when a table is unloaded or a method completes
 160      * execution.
 161      *
 162      * If this error happens, there may be very deep nesting of invoked
 163      * control methods, or there may be a bug where the IDs are not released.
 164      */
 165     Status = AE_OWNER_ID_LIMIT;
 166     ACPI_ERROR ((AE_INFO,
 167         "Could not allocate new OwnerId (255 max), AE_OWNER_ID_LIMIT"));
 168
 169 Exit:
 170     (void) AcpiUtReleaseMutex (ACPI_MTX_CACHES);
 171     return_ACPI_STATUS (Status);
 172 }
 173
 174
 175 /*******************************************************************************
 176  *
 177  * FUNCTION:    AcpiUtReleaseOwnerId
 178  *
 179  * PARAMETERS:  OwnerIdPtr          - Pointer to a previously allocated OwnerID
 180  *
 181  * RETURN:      None. No error is returned because we are either exiting a
 182  *              control method or unloading a table. Either way, we would
 183  *              ignore any error anyway.
 184  *
 185  * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255
 186  *
 187  ******************************************************************************/
 188
 189 void
 190 AcpiUtReleaseOwnerId (
 191     ACPI_OWNER_ID           *OwnerIdPtr)
 192 {
 193     ACPI_OWNER_ID           OwnerId = *OwnerIdPtr;
 194     ACPI_STATUS             Status;
 195     UINT32                  Index;
 196     UINT32                  Bit;
 197
 198
 199     ACPI_FUNCTION_TRACE_U32 (UtReleaseOwnerId, OwnerId);
 200
 201
 202     /* Always clear the input OwnerId (zero is an invalid ID) */
 203
 204     *OwnerIdPtr = 0;
 205
 206     /* Zero is not a valid OwnerID */
 207
 208     if (OwnerId == 0)
 209     {
 210         ACPI_ERROR ((AE_INFO, "Invalid OwnerId: 0x%2.2X", OwnerId));
 211         return_VOID;
 212     }
 213
 214     /* Mutex for the global ID mask */
 215
 216     Status = AcpiUtAcquireMutex (ACPI_MTX_CACHES);
 217     if (ACPI_FAILURE (Status))
 218     {
 219         return_VOID;
 220     }
 221
 222     /* Normalize the ID to zero */
 223
 224     OwnerId--;
 225
 226     /* Decode ID to index/offset pair */
 227
 228     Index = ACPI_DIV_32 (OwnerId);
 229     Bit = (UINT32) 1 << ACPI_MOD_32 (OwnerId);
 230
 231     /* Free the owner ID only if it is valid */
 232
 233     if (AcpiGbl_OwnerIdMask[Index] & Bit)
 234     {
 235         AcpiGbl_OwnerIdMask[Index] ^= Bit;
 236     }
 237     else
 238     {
 239         ACPI_ERROR ((AE_INFO,
 240             "Release of non-allocated OwnerId: 0x%2.2X", OwnerId + 1));
 241     }
 242
 243     (void) AcpiUtReleaseMutex (ACPI_MTX_CACHES);
 244     return_VOID;
 245 }