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v3.1
  1/******************************************************************************
  2 *
  3 * Module Name: evglock - Global Lock support
  4 *
  5 *****************************************************************************/
  6
  7/*
  8 * Copyright (C) 2000 - 2011, 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 "acevents.h"
 47#include "acinterp.h"
 48
 49#define _COMPONENT          ACPI_EVENTS
 50ACPI_MODULE_NAME("evglock")
 51
 52/* Local prototypes */
 53static u32 acpi_ev_global_lock_handler(void *context);
 54
 55/*******************************************************************************
 56 *
 57 * FUNCTION:    acpi_ev_init_global_lock_handler
 58 *
 59 * PARAMETERS:  None
 60 *
 61 * RETURN:      Status
 62 *
 63 * DESCRIPTION: Install a handler for the global lock release event
 64 *
 65 ******************************************************************************/
 66
 67acpi_status acpi_ev_init_global_lock_handler(void)
 68{
 69	acpi_status status;
 70
 71	ACPI_FUNCTION_TRACE(ev_init_global_lock_handler);
 72
 
 
 
 
 
 
 73	/* Attempt installation of the global lock handler */
 74
 75	status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL,
 76						  acpi_ev_global_lock_handler,
 77						  NULL);
 78
 79	/*
 80	 * If the global lock does not exist on this platform, the attempt to
 81	 * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
 82	 * Map to AE_OK, but mark global lock as not present. Any attempt to
 83	 * actually use the global lock will be flagged with an error.
 84	 */
 85	acpi_gbl_global_lock_present = FALSE;
 86	if (status == AE_NO_HARDWARE_RESPONSE) {
 87		ACPI_ERROR((AE_INFO,
 88			    "No response from Global Lock hardware, disabling lock"));
 89
 90		return_ACPI_STATUS(AE_OK);
 91	}
 92
 93	status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock);
 94	if (ACPI_FAILURE(status)) {
 95		return_ACPI_STATUS(status);
 96	}
 97
 98	acpi_gbl_global_lock_pending = FALSE;
 99	acpi_gbl_global_lock_present = TRUE;
100	return_ACPI_STATUS(status);
101}
102
103/*******************************************************************************
104 *
105 * FUNCTION:    acpi_ev_remove_global_lock_handler
106 *
107 * PARAMETERS:  None
108 *
109 * RETURN:      Status
110 *
111 * DESCRIPTION: Remove the handler for the Global Lock
112 *
113 ******************************************************************************/
114
115acpi_status acpi_ev_remove_global_lock_handler(void)
116{
117	acpi_status status;
118
119	ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler);
120
121	acpi_gbl_global_lock_present = FALSE;
122	status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL,
123						 acpi_ev_global_lock_handler);
124
125	return_ACPI_STATUS(status);
126}
127
128/*******************************************************************************
129 *
130 * FUNCTION:    acpi_ev_global_lock_handler
131 *
132 * PARAMETERS:  Context         - From thread interface, not used
133 *
134 * RETURN:      ACPI_INTERRUPT_HANDLED
135 *
136 * DESCRIPTION: Invoked directly from the SCI handler when a global lock
137 *              release interrupt occurs. If there is actually a pending
138 *              request for the lock, signal the waiting thread.
139 *
140 ******************************************************************************/
141
142static u32 acpi_ev_global_lock_handler(void *context)
143{
144	acpi_status status;
145	acpi_cpu_flags flags;
146
147	flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
148
149	/*
150	 * If a request for the global lock is not actually pending,
151	 * we are done. This handles "spurious" global lock interrupts
152	 * which are possible (and have been seen) with bad BIOSs.
153	 */
154	if (!acpi_gbl_global_lock_pending) {
155		goto cleanup_and_exit;
156	}
157
158	/*
159	 * Send a unit to the global lock semaphore. The actual acquisition
160	 * of the global lock will be performed by the waiting thread.
161	 */
162	status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);
163	if (ACPI_FAILURE(status)) {
164		ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));
165	}
166
167	acpi_gbl_global_lock_pending = FALSE;
168
169      cleanup_and_exit:
170
171	acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
172	return (ACPI_INTERRUPT_HANDLED);
173}
174
175/******************************************************************************
176 *
177 * FUNCTION:    acpi_ev_acquire_global_lock
178 *
179 * PARAMETERS:  Timeout         - Max time to wait for the lock, in millisec.
180 *
181 * RETURN:      Status
182 *
183 * DESCRIPTION: Attempt to gain ownership of the Global Lock.
184 *
185 * MUTEX:       Interpreter must be locked
186 *
187 * Note: The original implementation allowed multiple threads to "acquire" the
188 * Global Lock, and the OS would hold the lock until the last thread had
189 * released it. However, this could potentially starve the BIOS out of the
190 * lock, especially in the case where there is a tight handshake between the
191 * Embedded Controller driver and the BIOS. Therefore, this implementation
192 * allows only one thread to acquire the HW Global Lock at a time, and makes
193 * the global lock appear as a standard mutex on the OS side.
194 *
195 *****************************************************************************/
196
197acpi_status acpi_ev_acquire_global_lock(u16 timeout)
198{
199	acpi_cpu_flags flags;
200	acpi_status status;
201	u8 acquired = FALSE;
202
203	ACPI_FUNCTION_TRACE(ev_acquire_global_lock);
204
205	/*
206	 * Only one thread can acquire the GL at a time, the global_lock_mutex
207	 * enforces this. This interface releases the interpreter if we must wait.
208	 */
209	status =
210	    acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex.
211				      os_mutex, timeout);
212	if (ACPI_FAILURE(status)) {
213		return_ACPI_STATUS(status);
214	}
215
216	/*
217	 * Update the global lock handle and check for wraparound. The handle is
218	 * only used for the external global lock interfaces, but it is updated
219	 * here to properly handle the case where a single thread may acquire the
220	 * lock via both the AML and the acpi_acquire_global_lock interfaces. The
221	 * handle is therefore updated on the first acquire from a given thread
222	 * regardless of where the acquisition request originated.
223	 */
224	acpi_gbl_global_lock_handle++;
225	if (acpi_gbl_global_lock_handle == 0) {
226		acpi_gbl_global_lock_handle = 1;
227	}
228
229	/*
230	 * Make sure that a global lock actually exists. If not, just
231	 * treat the lock as a standard mutex.
232	 */
233	if (!acpi_gbl_global_lock_present) {
234		acpi_gbl_global_lock_acquired = TRUE;
235		return_ACPI_STATUS(AE_OK);
236	}
237
238	flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
239
240	do {
241
242		/* Attempt to acquire the actual hardware lock */
243
244		ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
245		if (acquired) {
246			acpi_gbl_global_lock_acquired = TRUE;
247			ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
248					  "Acquired hardware Global Lock\n"));
249			break;
250		}
251
252		/*
253		 * Did not get the lock. The pending bit was set above, and
254		 * we must now wait until we receive the global lock
255		 * released interrupt.
256		 */
257		acpi_gbl_global_lock_pending = TRUE;
258		acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
259
260		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
261				  "Waiting for hardware Global Lock\n"));
262
263		/*
264		 * Wait for handshake with the global lock interrupt handler.
265		 * This interface releases the interpreter if we must wait.
266		 */
267		status =
268		    acpi_ex_system_wait_semaphore
269		    (acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER);
270
271		flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
272
273	} while (ACPI_SUCCESS(status));
274
275	acpi_gbl_global_lock_pending = FALSE;
276	acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
277
278	return_ACPI_STATUS(status);
279}
280
281/*******************************************************************************
282 *
283 * FUNCTION:    acpi_ev_release_global_lock
284 *
285 * PARAMETERS:  None
286 *
287 * RETURN:      Status
288 *
289 * DESCRIPTION: Releases ownership of the Global Lock.
290 *
291 ******************************************************************************/
292
293acpi_status acpi_ev_release_global_lock(void)
294{
295	u8 pending = FALSE;
296	acpi_status status = AE_OK;
297
298	ACPI_FUNCTION_TRACE(ev_release_global_lock);
299
300	/* Lock must be already acquired */
301
302	if (!acpi_gbl_global_lock_acquired) {
303		ACPI_WARNING((AE_INFO,
304			      "Cannot release the ACPI Global Lock, it has not been acquired"));
305		return_ACPI_STATUS(AE_NOT_ACQUIRED);
306	}
307
308	if (acpi_gbl_global_lock_present) {
309
310		/* Allow any thread to release the lock */
311
312		ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending);
313
314		/*
315		 * If the pending bit was set, we must write GBL_RLS to the control
316		 * register
317		 */
318		if (pending) {
319			status =
320			    acpi_write_bit_register
321			    (ACPI_BITREG_GLOBAL_LOCK_RELEASE,
322			     ACPI_ENABLE_EVENT);
323		}
324
325		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
326				  "Released hardware Global Lock\n"));
327	}
328
329	acpi_gbl_global_lock_acquired = FALSE;
330
331	/* Release the local GL mutex */
332
333	acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex);
334	return_ACPI_STATUS(status);
335}
v3.5.6
  1/******************************************************************************
  2 *
  3 * Module Name: evglock - Global Lock support
  4 *
  5 *****************************************************************************/
  6
  7/*
  8 * Copyright (C) 2000 - 2012, 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 "acevents.h"
 47#include "acinterp.h"
 48
 49#define _COMPONENT          ACPI_EVENTS
 50ACPI_MODULE_NAME("evglock")
 51#if (!ACPI_REDUCED_HARDWARE)	/* Entire module */
 52/* Local prototypes */
 53static u32 acpi_ev_global_lock_handler(void *context);
 54
 55/*******************************************************************************
 56 *
 57 * FUNCTION:    acpi_ev_init_global_lock_handler
 58 *
 59 * PARAMETERS:  None
 60 *
 61 * RETURN:      Status
 62 *
 63 * DESCRIPTION: Install a handler for the global lock release event
 64 *
 65 ******************************************************************************/
 66
 67acpi_status acpi_ev_init_global_lock_handler(void)
 68{
 69	acpi_status status;
 70
 71	ACPI_FUNCTION_TRACE(ev_init_global_lock_handler);
 72
 73	/* If Hardware Reduced flag is set, there is no global lock */
 74
 75	if (acpi_gbl_reduced_hardware) {
 76		return_ACPI_STATUS(AE_OK);
 77	}
 78
 79	/* Attempt installation of the global lock handler */
 80
 81	status = acpi_install_fixed_event_handler(ACPI_EVENT_GLOBAL,
 82						  acpi_ev_global_lock_handler,
 83						  NULL);
 84
 85	/*
 86	 * If the global lock does not exist on this platform, the attempt to
 87	 * enable GBL_STATUS will fail (the GBL_ENABLE bit will not stick).
 88	 * Map to AE_OK, but mark global lock as not present. Any attempt to
 89	 * actually use the global lock will be flagged with an error.
 90	 */
 91	acpi_gbl_global_lock_present = FALSE;
 92	if (status == AE_NO_HARDWARE_RESPONSE) {
 93		ACPI_ERROR((AE_INFO,
 94			    "No response from Global Lock hardware, disabling lock"));
 95
 96		return_ACPI_STATUS(AE_OK);
 97	}
 98
 99	status = acpi_os_create_lock(&acpi_gbl_global_lock_pending_lock);
100	if (ACPI_FAILURE(status)) {
101		return_ACPI_STATUS(status);
102	}
103
104	acpi_gbl_global_lock_pending = FALSE;
105	acpi_gbl_global_lock_present = TRUE;
106	return_ACPI_STATUS(status);
107}
108
109/*******************************************************************************
110 *
111 * FUNCTION:    acpi_ev_remove_global_lock_handler
112 *
113 * PARAMETERS:  None
114 *
115 * RETURN:      Status
116 *
117 * DESCRIPTION: Remove the handler for the Global Lock
118 *
119 ******************************************************************************/
120
121acpi_status acpi_ev_remove_global_lock_handler(void)
122{
123	acpi_status status;
124
125	ACPI_FUNCTION_TRACE(ev_remove_global_lock_handler);
126
127	acpi_gbl_global_lock_present = FALSE;
128	status = acpi_remove_fixed_event_handler(ACPI_EVENT_GLOBAL,
129						 acpi_ev_global_lock_handler);
130
131	return_ACPI_STATUS(status);
132}
133
134/*******************************************************************************
135 *
136 * FUNCTION:    acpi_ev_global_lock_handler
137 *
138 * PARAMETERS:  Context         - From thread interface, not used
139 *
140 * RETURN:      ACPI_INTERRUPT_HANDLED
141 *
142 * DESCRIPTION: Invoked directly from the SCI handler when a global lock
143 *              release interrupt occurs. If there is actually a pending
144 *              request for the lock, signal the waiting thread.
145 *
146 ******************************************************************************/
147
148static u32 acpi_ev_global_lock_handler(void *context)
149{
150	acpi_status status;
151	acpi_cpu_flags flags;
152
153	flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
154
155	/*
156	 * If a request for the global lock is not actually pending,
157	 * we are done. This handles "spurious" global lock interrupts
158	 * which are possible (and have been seen) with bad BIOSs.
159	 */
160	if (!acpi_gbl_global_lock_pending) {
161		goto cleanup_and_exit;
162	}
163
164	/*
165	 * Send a unit to the global lock semaphore. The actual acquisition
166	 * of the global lock will be performed by the waiting thread.
167	 */
168	status = acpi_os_signal_semaphore(acpi_gbl_global_lock_semaphore, 1);
169	if (ACPI_FAILURE(status)) {
170		ACPI_ERROR((AE_INFO, "Could not signal Global Lock semaphore"));
171	}
172
173	acpi_gbl_global_lock_pending = FALSE;
174
175      cleanup_and_exit:
176
177	acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
178	return (ACPI_INTERRUPT_HANDLED);
179}
180
181/******************************************************************************
182 *
183 * FUNCTION:    acpi_ev_acquire_global_lock
184 *
185 * PARAMETERS:  Timeout         - Max time to wait for the lock, in millisec.
186 *
187 * RETURN:      Status
188 *
189 * DESCRIPTION: Attempt to gain ownership of the Global Lock.
190 *
191 * MUTEX:       Interpreter must be locked
192 *
193 * Note: The original implementation allowed multiple threads to "acquire" the
194 * Global Lock, and the OS would hold the lock until the last thread had
195 * released it. However, this could potentially starve the BIOS out of the
196 * lock, especially in the case where there is a tight handshake between the
197 * Embedded Controller driver and the BIOS. Therefore, this implementation
198 * allows only one thread to acquire the HW Global Lock at a time, and makes
199 * the global lock appear as a standard mutex on the OS side.
200 *
201 *****************************************************************************/
202
203acpi_status acpi_ev_acquire_global_lock(u16 timeout)
204{
205	acpi_cpu_flags flags;
206	acpi_status status;
207	u8 acquired = FALSE;
208
209	ACPI_FUNCTION_TRACE(ev_acquire_global_lock);
210
211	/*
212	 * Only one thread can acquire the GL at a time, the global_lock_mutex
213	 * enforces this. This interface releases the interpreter if we must wait.
214	 */
215	status =
216	    acpi_ex_system_wait_mutex(acpi_gbl_global_lock_mutex->mutex.
217				      os_mutex, timeout);
218	if (ACPI_FAILURE(status)) {
219		return_ACPI_STATUS(status);
220	}
221
222	/*
223	 * Update the global lock handle and check for wraparound. The handle is
224	 * only used for the external global lock interfaces, but it is updated
225	 * here to properly handle the case where a single thread may acquire the
226	 * lock via both the AML and the acpi_acquire_global_lock interfaces. The
227	 * handle is therefore updated on the first acquire from a given thread
228	 * regardless of where the acquisition request originated.
229	 */
230	acpi_gbl_global_lock_handle++;
231	if (acpi_gbl_global_lock_handle == 0) {
232		acpi_gbl_global_lock_handle = 1;
233	}
234
235	/*
236	 * Make sure that a global lock actually exists. If not, just
237	 * treat the lock as a standard mutex.
238	 */
239	if (!acpi_gbl_global_lock_present) {
240		acpi_gbl_global_lock_acquired = TRUE;
241		return_ACPI_STATUS(AE_OK);
242	}
243
244	flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
245
246	do {
247
248		/* Attempt to acquire the actual hardware lock */
249
250		ACPI_ACQUIRE_GLOBAL_LOCK(acpi_gbl_FACS, acquired);
251		if (acquired) {
252			acpi_gbl_global_lock_acquired = TRUE;
253			ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
254					  "Acquired hardware Global Lock\n"));
255			break;
256		}
257
258		/*
259		 * Did not get the lock. The pending bit was set above, and
260		 * we must now wait until we receive the global lock
261		 * released interrupt.
262		 */
263		acpi_gbl_global_lock_pending = TRUE;
264		acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
265
266		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
267				  "Waiting for hardware Global Lock\n"));
268
269		/*
270		 * Wait for handshake with the global lock interrupt handler.
271		 * This interface releases the interpreter if we must wait.
272		 */
273		status =
274		    acpi_ex_system_wait_semaphore
275		    (acpi_gbl_global_lock_semaphore, ACPI_WAIT_FOREVER);
276
277		flags = acpi_os_acquire_lock(acpi_gbl_global_lock_pending_lock);
278
279	} while (ACPI_SUCCESS(status));
280
281	acpi_gbl_global_lock_pending = FALSE;
282	acpi_os_release_lock(acpi_gbl_global_lock_pending_lock, flags);
283
284	return_ACPI_STATUS(status);
285}
286
287/*******************************************************************************
288 *
289 * FUNCTION:    acpi_ev_release_global_lock
290 *
291 * PARAMETERS:  None
292 *
293 * RETURN:      Status
294 *
295 * DESCRIPTION: Releases ownership of the Global Lock.
296 *
297 ******************************************************************************/
298
299acpi_status acpi_ev_release_global_lock(void)
300{
301	u8 pending = FALSE;
302	acpi_status status = AE_OK;
303
304	ACPI_FUNCTION_TRACE(ev_release_global_lock);
305
306	/* Lock must be already acquired */
307
308	if (!acpi_gbl_global_lock_acquired) {
309		ACPI_WARNING((AE_INFO,
310			      "Cannot release the ACPI Global Lock, it has not been acquired"));
311		return_ACPI_STATUS(AE_NOT_ACQUIRED);
312	}
313
314	if (acpi_gbl_global_lock_present) {
315
316		/* Allow any thread to release the lock */
317
318		ACPI_RELEASE_GLOBAL_LOCK(acpi_gbl_FACS, pending);
319
320		/*
321		 * If the pending bit was set, we must write GBL_RLS to the control
322		 * register
323		 */
324		if (pending) {
325			status =
326			    acpi_write_bit_register
327			    (ACPI_BITREG_GLOBAL_LOCK_RELEASE,
328			     ACPI_ENABLE_EVENT);
329		}
330
331		ACPI_DEBUG_PRINT((ACPI_DB_EXEC,
332				  "Released hardware Global Lock\n"));
333	}
334
335	acpi_gbl_global_lock_acquired = FALSE;
336
337	/* Release the local GL mutex */
338
339	acpi_os_release_mutex(acpi_gbl_global_lock_mutex->mutex.os_mutex);
340	return_ACPI_STATUS(status);
341}
342
343#endif				/* !ACPI_REDUCED_HARDWARE */