drivers/acpi/acpica/utownerid.c

   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 }