1/*
2 * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
3 *
4 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. The rights granted to you under the License
10 * may not be used to create, or enable the creation or redistribution of,
11 * unlawful or unlicensed copies of an Apple operating system, or to
12 * circumvent, violate, or enable the circumvention or violation of, any
13 * terms of an Apple operating system software license agreement.
14 *
15 * Please obtain a copy of the License at
16 * http://www.opensource.apple.com/apsl/ and read it before using this file.
17 *
18 * The Original Code and all software distributed under the License are
19 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
20 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
21 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
23 * Please see the License for the specific language governing rights and
24 * limitations under the License.
25 *
26 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
27 */
28/*
29 * @OSF_COPYRIGHT@
30 */
31/*
32 * Mach Operating System
33 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
34 * All Rights Reserved.
35 *
36 * Permission to use, copy, modify and distribute this software and its
37 * documentation is hereby granted, provided that both the copyright
38 * notice and this permission notice appear in all copies of the
39 * software, derivative works or modified versions, and any portions
40 * thereof, and that both notices appear in supporting documentation.
41 *
42 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
43 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
44 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
45 *
46 * Carnegie Mellon requests users of this software to return to
47 *
48 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
49 *  School of Computer Science
50 *  Carnegie Mellon University
51 *  Pittsburgh PA 15213-3890
52 *
53 * any improvements or extensions that they make and grant Carnegie Mellon
54 * the rights to redistribute these changes.
55 */
56/*
57 */
58
59/*
60 *
61 *	This file contains routines to check whether an ast is needed.
62 *
63 *	ast_check() - check whether ast is needed for interrupt or context
64 *	switch.  Usually called by clock interrupt handler.
65 *
66 */
67
68#include <cputypes.h>
69#include <platforms.h>
70
71#include <kern/ast.h>
72#include <kern/counters.h>
73#include <kern/cpu_number.h>
74#include <kern/misc_protos.h>
75#include <kern/queue.h>
76#include <kern/sched_prim.h>
77#include <kern/thread.h>
78#include <kern/processor.h>
79#include <kern/spl.h>
80#include <kern/wait_queue.h>
81#include <kern/ledger.h>
82#include <mach/policy.h>
83#include <machine/trap.h> // for CHUD AST hook
84#include <machine/pal_routines.h>
85#include <security/mac_mach_internal.h> // for MACF AST hook
86
87volatile perfASTCallback perfASTHook;
88
89
90void
91ast_init(void)
92{
93}
94
95extern void chudxnu_thread_ast(thread_t); // XXX this should probably be in a header...
96
97/*
98 * Called at splsched.
99 */
100void
101ast_taken(
102	ast_t		reasons,
103	boolean_t	enable
104)
105{
106	boolean_t		preempt_trap = (reasons == AST_PREEMPTION);
107	ast_t			*myast = ast_pending();
108	thread_t		thread = current_thread();
109	perfASTCallback	perf_hook = perfASTHook;
110
111	/*
112	 * CHUD hook - all threads including idle processor threads
113	 */
114	if (perf_hook) {
115		if (*myast & AST_CHUD_ALL) {
116			(*perf_hook)(reasons, myast);
117
118			if (*myast == AST_NONE)
119				return;
120		}
121	}
122	else
123		*myast &= ~AST_CHUD_ALL;
124
125	reasons &= *myast;
126	*myast &= ~reasons;
127
128	/*
129	 * Handle ASTs for all threads
130	 * except idle processor threads.
131	 */
132	if (!(thread->state & TH_IDLE)) {
133		/*
134		 * Check for urgent preemption.
135		 */
136		if (	(reasons & AST_URGENT)				&&
137				wait_queue_assert_possible(thread)		) {
138			if (reasons & AST_PREEMPT) {
139				counter(c_ast_taken_block++);
140				thread_block_reason(THREAD_CONTINUE_NULL, NULL,
141										AST_PREEMPT | AST_URGENT);
142			}
143
144			reasons &= ~AST_PREEMPTION;
145		}
146
147		/*
148		 * The kernel preempt traps
149		 * skip all other ASTs.
150		 */
151		if (!preempt_trap) {
152			ml_set_interrupts_enabled(enable);
153
154#ifdef	MACH_BSD
155			/*
156			 * Handle BSD hook.
157			 */
158			if (reasons & AST_BSD) {
159				thread_ast_clear(thread, AST_BSD);
160				bsd_ast(thread);
161			}
162#endif
163#if CONFIG_MACF
164			/*
165			 * Handle MACF hook.
166			 */
167			if (reasons & AST_MACF) {
168				thread_ast_clear(thread, AST_MACF);
169				mac_thread_userret(thread);
170			}
171#endif
172			/*
173			 * Thread APC hook.
174			 */
175			if (reasons & AST_APC)
176				act_execute_returnhandlers();
177
178			if (reasons & AST_LEDGER) {
179				thread_ast_clear(thread, AST_LEDGER);
180				ledger_ast(thread);
181			}
182
183			/*
184			 * Kernel Profiling Hook
185			 */
186			if (reasons & AST_KPERF)
187			{
188				thread_ast_clear(thread, AST_KPERF);
189				chudxnu_thread_ast(thread);
190			}
191
192			ml_set_interrupts_enabled(FALSE);
193
194			/*
195			 * Check for preemption.
196			 */
197			if (reasons & AST_PREEMPT)
198				reasons = csw_check(current_processor());
199
200			if (	(reasons & AST_PREEMPT)				&&
201					wait_queue_assert_possible(thread)		) {
202				counter(c_ast_taken_block++);
203				thread_block_reason((thread_continue_t)thread_exception_return, NULL, AST_PREEMPT);
204			}
205		}
206	}
207
208	ml_set_interrupts_enabled(enable);
209}
210
211/*
212 * Called at splsched.
213 */
214void
215ast_check(
216	processor_t		processor)
217{
218	thread_t			thread = processor->active_thread;
219
220	processor->current_pri = thread->sched_pri;
221	processor->current_thmode = thread->sched_mode;
222	if (	processor->state == PROCESSOR_RUNNING		||
223			processor->state == PROCESSOR_SHUTDOWN		) {
224		ast_t			preempt;
225
226		/*
227		 *	Propagate thread ast to processor.
228		 */
229		pal_ast_check(thread);
230
231		ast_propagate(thread->ast);
232
233		/*
234		 *	Context switch check.
235		 */
236		if ((preempt = csw_check(processor)) != AST_NONE)
237			ast_on(preempt);
238	}
239}
240