1/*******************************************************************************
  2 *
  3 * Module Name: utownerid - Support for Table/Method Owner IDs
  4 *
  5 ******************************************************************************/
  6
  7/*
  8 * Copyright (C) 2000 - 2016, 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/acpi.h>
 45#include "accommon.h"
 46#include "acnamesp.h"
 47
 48#define _COMPONENT          ACPI_UTILITIES
 49ACPI_MODULE_NAME("utownerid")
 50
 51/*******************************************************************************
 52 *
 53 * FUNCTION:    acpi_ut_allocate_owner_id
 54 *
 55 * PARAMETERS:  owner_id        - Where the new owner ID is returned
 56 *
 57 * RETURN:      Status
 58 *
 59 * DESCRIPTION: Allocate a table or method owner ID. The owner ID is used to
 60 *              track objects created by the table or method, to be deleted
 61 *              when the method exits or the table is unloaded.
 62 *
 63 ******************************************************************************/
 64acpi_status acpi_ut_allocate_owner_id(acpi_owner_id * owner_id)
 65{
 66	u32 i;
 67	u32 j;
 68	u32 k;
 69	acpi_status status;
 70
 71	ACPI_FUNCTION_TRACE(ut_allocate_owner_id);
 72
 73	/* Guard against multiple allocations of ID to the same location */
 74
 75	if (*owner_id) {
 76		ACPI_ERROR((AE_INFO,
 77			    "Owner ID [0x%2.2X] already exists", *owner_id));
 78		return_ACPI_STATUS(AE_ALREADY_EXISTS);
 79	}
 80
 81	/* Mutex for the global ID mask */
 82
 83	status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
 84	if (ACPI_FAILURE(status)) {
 85		return_ACPI_STATUS(status);
 86	}
 87
 88	/*
 89	 * Find a free owner ID, cycle through all possible IDs on repeated
 90	 * allocations. (ACPI_NUM_OWNERID_MASKS + 1) because first index
 91	 * may have to be scanned twice.
 92	 */
 93	for (i = 0, j = acpi_gbl_last_owner_id_index;
 94	     i < (ACPI_NUM_OWNERID_MASKS + 1); i++, j++) {
 95		if (j >= ACPI_NUM_OWNERID_MASKS) {
 96			j = 0;	/* Wraparound to start of mask array */
 97		}
 98
 99		for (k = acpi_gbl_next_owner_id_offset; k < 32; k++) {
100			if (acpi_gbl_owner_id_mask[j] == ACPI_UINT32_MAX) {
101
102				/* There are no free IDs in this mask */
103
104				break;
105			}
106
107			if (!(acpi_gbl_owner_id_mask[j] & (1 << k))) {
108				/*
109				 * Found a free ID. The actual ID is the bit index plus one,
110				 * making zero an invalid Owner ID. Save this as the last ID
111				 * allocated and update the global ID mask.
112				 */
113				acpi_gbl_owner_id_mask[j] |= (1 << k);
114
115				acpi_gbl_last_owner_id_index = (u8)j;
116				acpi_gbl_next_owner_id_offset = (u8)(k + 1);
117
118				/*
119				 * Construct encoded ID from the index and bit position
120				 *
121				 * Note: Last [j].k (bit 255) is never used and is marked
122				 * permanently allocated (prevents +1 overflow)
123				 */
124				*owner_id =
125				    (acpi_owner_id) ((k + 1) + ACPI_MUL_32(j));
126
127				ACPI_DEBUG_PRINT((ACPI_DB_VALUES,
128						  "Allocated OwnerId: %2.2X\n",
129						  (unsigned int)*owner_id));
130				goto exit;
131			}
132		}
133
134		acpi_gbl_next_owner_id_offset = 0;
135	}
136
137	/*
138	 * All owner_ids have been allocated. This typically should
139	 * not happen since the IDs are reused after deallocation. The IDs are
140	 * allocated upon table load (one per table) and method execution, and
141	 * they are released when a table is unloaded or a method completes
142	 * execution.
143	 *
144	 * If this error happens, there may be very deep nesting of invoked
145	 * control methods, or there may be a bug where the IDs are not released.
146	 */
147	status = AE_OWNER_ID_LIMIT;
148	ACPI_ERROR((AE_INFO,
149		    "Could not allocate new OwnerId (255 max), AE_OWNER_ID_LIMIT"));
150
151exit:
152	(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
153	return_ACPI_STATUS(status);
154}
155
156/*******************************************************************************
157 *
158 * FUNCTION:    acpi_ut_release_owner_id
159 *
160 * PARAMETERS:  owner_id_ptr        - Pointer to a previously allocated owner_ID
161 *
162 * RETURN:      None. No error is returned because we are either exiting a
163 *              control method or unloading a table. Either way, we would
164 *              ignore any error anyway.
165 *
166 * DESCRIPTION: Release a table or method owner ID. Valid IDs are 1 - 255
167 *
168 ******************************************************************************/
169
170void acpi_ut_release_owner_id(acpi_owner_id * owner_id_ptr)
171{
172	acpi_owner_id owner_id = *owner_id_ptr;
173	acpi_status status;
174	u32 index;
175	u32 bit;
176
177	ACPI_FUNCTION_TRACE_U32(ut_release_owner_id, owner_id);
178
179	/* Always clear the input owner_id (zero is an invalid ID) */
180
181	*owner_id_ptr = 0;
182
183	/* Zero is not a valid owner_ID */
184
185	if (owner_id == 0) {
186		ACPI_ERROR((AE_INFO, "Invalid OwnerId: 0x%2.2X", owner_id));
187		return_VOID;
188	}
189
190	/* Mutex for the global ID mask */
191
192	status = acpi_ut_acquire_mutex(ACPI_MTX_CACHES);
193	if (ACPI_FAILURE(status)) {
194		return_VOID;
195	}
196
197	/* Normalize the ID to zero */
198
199	owner_id--;
200
201	/* Decode ID to index/offset pair */
202
203	index = ACPI_DIV_32(owner_id);
204	bit = 1 << ACPI_MOD_32(owner_id);
205
206	/* Free the owner ID only if it is valid */
207
208	if (acpi_gbl_owner_id_mask[index] & bit) {
209		acpi_gbl_owner_id_mask[index] ^= bit;
210	} else {
211		ACPI_ERROR((AE_INFO,
212			    "Release of non-allocated OwnerId: 0x%2.2X",
213			    owner_id + 1));
214	}
215
216	(void)acpi_ut_release_mutex(ACPI_MTX_CACHES);
217	return_VOID;
218}