1 /*-
2 * Copyright (c) 2002 Matthew Dillon. All Rights Reserved.
3 * Redistribution and use in source and binary forms, with or without
4 * modification, are permitted provided that the following conditions
5 * are met:
6 * 1. Redistributions of source code must retain the above copyright
7 * notice, this list of conditions and the following disclaimer.
8 * 2. Redistributions in binary form must reproduce the above copyright
9 * notice, this list of conditions and the following disclaimer in the
10 * documentation and/or other materials provided with the distribution.
11 * 4. Neither the name of the University nor the names of its contributors
12 * may be used to endorse or promote products derived from this software
13 * without specific prior written permission.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
21 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
24 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 * This file contains prototypes and high-level inlines related to
28 * machine-level critical function support:
29 *
30 * cpu_critical_enter() - inlined
31 * cpu_critical_exit() - inlined
32 * cpu_critical_fork_exit() - prototyped
33 * related support functions residing
34 * in <arch>/<arch>/critical.c - prototyped
35 *
36 * $FreeBSD: releng/5.3/sys/i386/include/critical.h 132700 2004-07-27 16:41:01Z rwatson $
37 */
38
39 #ifndef _MACHINE_CRITICAL_H_
40 #define _MACHINE_CRITICAL_H_
41
42 __BEGIN_DECLS
43
44 /*
45 * Prototypes - see <arch>/<arch>/critical.c
46 */
47 void cpu_critical_fork_exit(void);
48
49 #if defined(__GNUC__) || defined(__INTEL_COMPILER)
50
51 /*
52 * cpu_critical_enter:
53 *
54 * This routine is called from critical_enter() on the 0->1 transition
55 * of td_critnest, prior to it being incremented to 1.
56 *
57 * If new-style critical section handling we do not have to do anything.
58 * However, as a side effect any interrupts occuring while td_critnest
59 * is non-zero will be deferred.
60 */
61 static __inline void
62 cpu_critical_enter(struct thread *td)
63 {
64 td->td_md.md_savecrit = intr_disable();
65 }
66
67 /*
68 * cpu_critical_exit:
69 *
70 * This routine is called from critical_exit() on a 1->0 transition
71 * of td_critnest, after it has been decremented to 0. We are
72 * exiting the last critical section.
73 *
74 * Note that the td->critnest (1->0) transition interrupt race against
75 * our int_pending/unpend() check below is handled by the interrupt
76 * code for us, so we do not have to do anything fancy.
77 */
78 static __inline void
79 cpu_critical_exit(struct thread *td)
80 {
81 intr_restore(td->td_md.md_savecrit);
82 }
83
84 #else /* !(__GNUC__ || __INTEL_COMPILER) */
85
86 void cpu_critical_enter(struct thread *td);
87 void cpu_critical_exit(struct thread *td);
88
89 #endif /* __GNUC__ || __INTEL_COMPILER */
90
91 __END_DECLS
92
93 #endif /* !_MACHINE_CRITICAL_H_ */
94
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