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Diffstat (limited to '')
| -rw-r--r-- | drivers/acpi/acpica/utownerid.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/acpi/acpica/utownerid.c b/drivers/acpi/acpica/utownerid.c new file mode 100644 index 000000000..d3525ef8e --- /dev/null +++ b/drivers/acpi/acpica/utownerid.c @@ -0,0 +1,188 @@ +// 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; +} |