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1 | /* $NetBSD: mutex.h,v 1.22 2020/03/05 15:56:55 riastradh Exp $ */ | | 1 | /* $NetBSD: mutex.h,v 1.23 2020/03/05 17:58:08 riastradh Exp $ */ |
2 | | | 2 | |
3 | /*- | | 3 | /*- |
4 | * Copyright (c) 2002, 2007 The NetBSD Foundation, Inc. | | 4 | * Copyright (c) 2002, 2007 The NetBSD Foundation, Inc. |
5 | * All rights reserved. | | 5 | * All rights reserved. |
6 | * | | 6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation | | 7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Jason R. Thorpe and Andrew Doran. | | 8 | * by Jason R. Thorpe and Andrew Doran. |
9 | * | | 9 | * |
10 | * Redistribution and use in source and binary forms, with or without | | 10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions | | 11 | * modification, are permitted provided that the following conditions |
12 | * are met: | | 12 | * are met: |
13 | * 1. Redistributions of source code must retain the above copyright | | 13 | * 1. Redistributions of source code must retain the above copyright |
14 | * notice, this list of conditions and the following disclaimer. | | 14 | * notice, this list of conditions and the following disclaimer. |
15 | * 2. Redistributions in binary form must reproduce the above copyright | | 15 | * 2. Redistributions in binary form must reproduce the above copyright |
16 | * notice, this list of conditions and the following disclaimer in the | | 16 | * notice, this list of conditions and the following disclaimer in the |
17 | * documentation and/or other materials provided with the distribution. | | 17 | * documentation and/or other materials provided with the distribution. |
18 | * | | 18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS | | 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED | | 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | | 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS | | 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR | | 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF | | 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS | | 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN | | 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | | 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | | 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
29 | * POSSIBILITY OF SUCH DAMAGE. | | 29 | * POSSIBILITY OF SUCH DAMAGE. |
30 | */ | | 30 | */ |
31 | | | 31 | |
32 | #ifndef _ARM_MUTEX_H_ | | 32 | #ifndef _ARM_MUTEX_H_ |
33 | #define _ARM_MUTEX_H_ | | 33 | #define _ARM_MUTEX_H_ |
34 | | | 34 | |
35 | /* | | 35 | /* |
36 | * The ARM mutex implementation is troublesome, because pre-v6 ARM lacks a | | 36 | * The ARM mutex implementation is troublesome, because pre-v6 ARM lacks a |
37 | * compare-and-swap operation. However, there aren't any MP pre-v6 ARM | | 37 | * compare-and-swap operation. However, there aren't any MP pre-v6 ARM |
38 | * systems to speak of. | | 38 | * systems to speak of. |
39 | * | | 39 | * |
40 | * ARMv6 and later, however, does have ldrex/strex, and can thus implement an | | 40 | * ARMv6 and later, however, does have ldrex/strex, and can thus implement an |
41 | * MP-safe compare-and-swap. | | 41 | * MP-safe compare-and-swap. |
42 | * | | 42 | * |
43 | * So, what we have done is implement simple mutexes using a compare-and-swap. | | 43 | * So, what we have done is implement simple mutexes using a compare-and-swap. |
44 | * We support pre-ARMv6 by implementing CAS as a restartable atomic sequence | | 44 | * We support pre-ARMv6 by implementing CAS as a restartable atomic sequence |
45 | * that is checked by the IRQ vector. | | 45 | * that is checked by the IRQ vector. |
46 | * | | 46 | * |
47 | */ | | 47 | */ |
48 | | | 48 | |
49 | struct kmutex { | | 49 | struct kmutex { |
50 | union { | | 50 | union { |
51 | /* Adaptive mutex */ | | 51 | /* Adaptive mutex */ |
52 | volatile uintptr_t mtxa_owner; /* 0-3 */ | | 52 | volatile uintptr_t mtxa_owner; /* 0-3 */ |
53 | | | 53 | |
| | | 54 | #ifdef _KERNEL |
54 | /* Spin mutex */ | | 55 | /* Spin mutex */ |
55 | struct { | | 56 | struct { |
56 | /* | | 57 | /* |
57 | * Since the low bit of mtxa_owner is used to flag this | | 58 | * Since the low bit of mtxa_owner is used to flag this |
58 | * mutex as a spin mutex, we can't use the first byte | | 59 | * mutex as a spin mutex, we can't use the first byte |
59 | * or the last byte to store the ipl or lock values. | | 60 | * or the last byte to store the ipl or lock values. |
60 | */ | | 61 | */ |
61 | volatile uint8_t mtxs_dummy; | | 62 | volatile uint8_t mtxs_dummy; |
62 | ipl_cookie_t mtxs_ipl; | | 63 | ipl_cookie_t mtxs_ipl; |
63 | __cpu_simple_lock_t mtxs_lock; | | 64 | __cpu_simple_lock_t mtxs_lock; |
64 | volatile uint8_t mtxs_unused; | | 65 | volatile uint8_t mtxs_unused; |
65 | } s; | | 66 | } s; |
| | | 67 | #endif |
66 | } u; | | 68 | } u; |
67 | }; | | 69 | }; |
68 | | | 70 | |
69 | #ifdef __MUTEX_PRIVATE | | 71 | #ifdef __MUTEX_PRIVATE |
70 | | | 72 | |
71 | #define mtx_owner u.mtxa_owner | | 73 | #define mtx_owner u.mtxa_owner |
72 | #define mtx_ipl u.s.mtxs_ipl | | 74 | #define mtx_ipl u.s.mtxs_ipl |
73 | #define mtx_lock u.s.mtxs_lock | | 75 | #define mtx_lock u.s.mtxs_lock |
74 | | | 76 | |
75 | #if 0 | | 77 | #if 0 |
76 | #define __HAVE_MUTEX_STUBS 1 | | 78 | #define __HAVE_MUTEX_STUBS 1 |
77 | #define __HAVE_SPIN_MUTEX_STUBS 1 | | 79 | #define __HAVE_SPIN_MUTEX_STUBS 1 |
78 | #endif | | 80 | #endif |
79 | #define __HAVE_SIMPLE_MUTEXES 1 | | 81 | #define __HAVE_SIMPLE_MUTEXES 1 |
80 | | | 82 | |
81 | #define MUTEX_CAS(p, o, n) \ | | 83 | #define MUTEX_CAS(p, o, n) \ |
82 | (atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) | | 84 | (atomic_cas_ulong((volatile unsigned long *)(p), (o), (n)) == (o)) |
83 | #ifdef MULTIPROCESSOR | | 85 | #ifdef MULTIPROCESSOR |
84 | #define MUTEX_SMT_PAUSE() __asm __volatile("wfe") | | 86 | #define MUTEX_SMT_PAUSE() __asm __volatile("wfe") |
85 | #define MUTEX_SMT_WAKE() __asm __volatile("sev") | | 87 | #define MUTEX_SMT_WAKE() __asm __volatile("sev") |
86 | #endif | | 88 | #endif |
87 | | | 89 | |
88 | #endif /* __MUTEX_PRIVATE */ | | 90 | #endif /* __MUTEX_PRIVATE */ |
89 | | | 91 | |
90 | #endif /* _ARM_MUTEX_H_ */ | | 92 | #endif /* _ARM_MUTEX_H_ */ |