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       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                 :       7923 : acpi_status acpi_ut_allocate_owner_id(acpi_owner_id *owner_id)
      29                 :            : {
      30                 :       7923 :         u32 i;
      31                 :       7923 :         u32 j;
      32                 :       7923 :         u32 k;
      33                 :       7923 :         acpi_status status;
      34                 :            : 
      35                 :       7923 :         ACPI_FUNCTION_TRACE(ut_allocate_owner_id);
      36                 :            : 
      37                 :            :         /* Guard against multiple allocations of ID to the same location */
      38                 :            : 
      39         [ -  + ]:       7923 :         if (*owner_id) {
      40                 :          0 :                 ACPI_ERROR((AE_INFO,
      41                 :            :                             "Owner ID [0x%3.3X] already exists", *owner_id));
      42                 :          0 :                 return_ACPI_STATUS(AE_ALREADY_EXISTS);
      43                 :            :         }
      44                 :            : 
      45                 :            :         /* Mutex for the global ID mask */
      46                 :            : 
      47                 :       7923 :         status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
      48         [ +  - ]:       7923 :         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                 :       7923 :         for (i = 0, j = acpi_gbl_last_owner_id_index;
      58         [ +  - ]:       8157 :              i < (ACPI_NUM_OWNERID_MASKS + 1); i++, j++) {
      59         [ -  + ]:       8157 :                 if (j >= ACPI_NUM_OWNERID_MASKS) {
      60                 :          0 :                         j = 0;  /* Wraparound to start of mask array */
      61                 :            :                 }
      62                 :            : 
      63         [ +  + ]:       8157 :                 for (k = acpi_gbl_next_owner_id_offset; k < 32; k++) {
      64         [ +  - ]:       7923 :                         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         [ +  - ]:       7923 :                         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                 :       7923 :                                 acpi_gbl_owner_id_mask[j] |= ((u32)1 << k);
      84                 :            : 
      85                 :       7923 :                                 acpi_gbl_last_owner_id_index = (u8)j;
      86                 :       7923 :                                 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 4095) is never used and is marked
      92                 :            :                                  * permanently allocated (prevents +1 overflow)
      93                 :            :                                  */
      94                 :       7923 :                                 *owner_id =
      95                 :       7923 :                                     (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                 :       7923 :                                                   (unsigned int)*owner_id));
     100                 :       7923 :                                 goto exit;
     101                 :            :                         }
     102                 :            :                 }
     103                 :            : 
     104                 :        234 :                 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                 :          0 :         status = AE_OWNER_ID_LIMIT;
     118                 :          0 :         ACPI_ERROR((AE_INFO,
     119                 :            :                     "Could not allocate new OwnerId (4095 max), AE_OWNER_ID_LIMIT"));
     120                 :            : 
     121                 :       7923 : exit:
     122                 :       7923 :         (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
     123                 :       7923 :         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                 :       7845 : void acpi_ut_release_owner_id(acpi_owner_id *owner_id_ptr)
     141                 :            : {
     142                 :       7845 :         acpi_owner_id owner_id = *owner_id_ptr;
     143                 :       7845 :         acpi_status status;
     144                 :       7845 :         u32 index;
     145                 :       7845 :         u32 bit;
     146                 :            : 
     147                 :       7845 :         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                 :       7845 :         *owner_id_ptr = 0;
     152                 :            : 
     153                 :            :         /* Zero is not a valid owner_ID */
     154                 :            : 
     155         [ -  + ]:       7845 :         if (owner_id == 0) {
     156                 :          0 :                 ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%3.3X", owner_id));
     157                 :          0 :                 return_VOID;
     158                 :            :         }
     159                 :            : 
     160                 :            :         /* Mutex for the global ID mask */
     161                 :            : 
     162                 :       7845 :         status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
     163         [ +  - ]:       7845 :         if (ACPI_FAILURE(status)) {
     164                 :            :                 return_VOID;
     165                 :            :         }
     166                 :            : 
     167                 :            :         /* Normalize the ID to zero */
     168                 :            : 
     169                 :       7845 :         owner_id--;
     170                 :            : 
     171                 :            :         /* Decode ID to index/offset pair */
     172                 :            : 
     173                 :       7845 :         index = ACPI_DIV_32(owner_id);
     174                 :       7845 :         bit = (u32)1 << ACPI_MOD_32(owner_id);
     175                 :            : 
     176                 :            :         /* Free the owner ID only if it is valid */
     177                 :            : 
     178         [ +  - ]:       7845 :         if (acpi_gbl_owner_id_mask[index] & bit) {
     179                 :       7845 :                 acpi_gbl_owner_id_mask[index] ^= bit;
     180                 :            :         } else {
     181                 :          0 :                 ACPI_ERROR((AE_INFO,
     182                 :            :                             "Attempted release of non-allocated OwnerId: 0x%3.3X",
     183                 :            :                             owner_id + 1));
     184                 :            :         }
     185                 :            : 
     186                 :       7845 :         (void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
     187                 :       7845 :         return_VOID;
     188                 :            : }