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// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/*******************************************************************************
*
* Module Name: utownerid - Support for Table/Method Owner IDs
*
******************************************************************************/
#include <acpi/acpi.h>
#include "accommon.h"
#include "acnamesp.h"
#define _COMPONENT ACPI_UTILITIES
ACPI_MODULE_NAME("utownerid")
/*******************************************************************************
*
* FUNCTION: acpi_ut_allocate_owner_id
*
* PARAMETERS: owner_id - Where the new owner ID is returned
*
* RETURN: Status
*
* DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to
* track objects created by the table or method, to be deleted
* when the method exits or the table is unloaded.
*
******************************************************************************/
acpi_status acpi_ut_allocate_owner_id(acpi_owner_id *owner_id)
{
u32 i;
u32 j;
u32 k;
acpi_status status;
ACPI_FUNCTION_TRACE(ut_allocate_owner_id);
/* Guard against multiple allocations of ID to the same location */
if (*owner_id) {
ACPI_ERROR((AE_INFO,
"Owner ID [0x%3.3X] already exists", *owner_id));
return_ACPI_STATUS(AE_ALREADY_EXISTS);
}
/* Mutex for the global ID mask */
status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
}
/*
* Find a free owner ID, cycle through all possible IDs on repeated
* allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index
* may have to be scanned twice.
*/
for (i = 0, j = acpi_gbl_last_owner_id_index;
i < (ACPI_NUM_OWNERID_MASKS + 1); i++, j++) {
if (j >= ACPI_NUM_OWNERID_MASKS) {
j = 0; /* Wraparound to start of mask array */
}
for (k = acpi_gbl_next_owner_id_offset; k < 32; k++) {
if (acpi_gbl_owner_id_mask[j] == ACPI_UINT32_MAX) {
/* There are no free IDs in this mask */
break;
}
/*
* Note: the u32 cast ensures that 1 is stored as a unsigned
* integer. Omitting the cast may result in 1 being stored as an
* int. Some compilers or runtime error detection may flag this as
* an error.
*/
if (!(acpi_gbl_owner_id_mask[j] & ((u32)1 << k))) {
/*
* Found a free ID. The actual ID is the bit index plus one,
* making zero an invalid Owner ID. Save this as the last ID
* allocated and update the global ID mask.
*/
acpi_gbl_owner_id_mask[j] |= ((u32)1 << k);
acpi_gbl_last_owner_id_index = (u8)j;
acpi_gbl_next_owner_id_offset = (u8)(k + 1);
/*
* Construct encoded ID from the index and bit position
*
* Note: Last [j].k (bit 4095) is never used and is marked
* permanently allocated (prevents +1 overflow)
*/
*owner_id =
(acpi_owner_id)((k + 1) + ACPI_MUL_32(j));
ACPI_DEBUG_PRINT((ACPI_DB_VALUES,
"Allocated OwnerId: 0x%3.3X\n",
(unsigned int)*owner_id));
goto exit;
}
}
acpi_gbl_next_owner_id_offset = 0;
}
/*
* All owner_ids have been allocated. This typically should
* not happen since the IDs are reused after deallocation. The IDs are
* allocated upon table load (one per table) and method execution, and
* they are released when a table is unloaded or a method completes
* execution.
*
* If this error happens, there may be very deep nesting of invoked
* control methods, or there may be a bug where the IDs are not released.
*/
status = AE_OWNER_ID_LIMIT;
ACPI_ERROR((AE_INFO,
"Could not allocate new OwnerId (4095 max), AE_OWNER_ID_LIMIT"));
exit:
(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
return_ACPI_STATUS(status);
}
/*******************************************************************************
*
* FUNCTION: acpi_ut_release_owner_id
*
* PARAMETERS: owner_id_ptr - Pointer to a previously allocated owner_ID
*
* RETURN: None. No error is returned because we are either exiting a
* control method or unloading a table. Either way, we would
* ignore any error anyway.
*
* DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255
*
******************************************************************************/
void acpi_ut_release_owner_id(acpi_owner_id *owner_id_ptr)
{
acpi_owner_id owner_id = *owner_id_ptr;
acpi_status status;
u32 index;
u32 bit;
ACPI_FUNCTION_TRACE_U32(ut_release_owner_id, owner_id);
/* Always clear the input owner_id (zero is an invalid ID) */
*owner_id_ptr = 0;
/* Zero is not a valid owner_ID */
if (owner_id == 0) {
ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%3.3X", owner_id));
return_VOID;
}
/* Mutex for the global ID mask */
status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
if (ACPI_FAILURE(status)) {
return_VOID;
}
/* Normalize the ID to zero */
owner_id--;
/* Decode ID to index/offset pair */
index = ACPI_DIV_32(owner_id);
bit = (u32)1 << ACPI_MOD_32(owner_id);
/* Free the owner ID only if it is valid */
if (acpi_gbl_owner_id_mask[index] & bit) {
acpi_gbl_owner_id_mask[index] ^= bit;
} else {
ACPI_ERROR((AE_INFO,
"Attempted release of non-allocated OwnerId: 0x%3.3X",
owner_id + 1));
}
(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
return_VOID;
}
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