1 | /* $NetBSD: idt.c,v 1.4 2016/08/27 14:19:47 maxv Exp $ */ |
2 | |
3 | /*- |
4 | * Copyright (c) 1996, 1997, 1998, 2000, 2009 The NetBSD Foundation, Inc. |
5 | * All rights reserved. |
6 | * |
7 | * This code is derived from software contributed to The NetBSD Foundation |
8 | * by Charles M. Hannum, by Jason R. Thorpe of the Numerical Aerospace |
9 | * Simulation Facility NASA Ames Research Center, and by Andrew Doran. |
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 | * 2. Redistributions in binary form must reproduce the above copyright |
17 | * notice, this list of conditions and the following disclaimer in the |
18 | * documentation and/or other materials provided with the distribution. |
19 | * |
20 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
22 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
23 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
24 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
30 | * POSSIBILITY OF SUCH DAMAGE. |
31 | */ |
32 | |
33 | /*- |
34 | * Copyright (c) 1982, 1987, 1990 The Regents of the University of California. |
35 | * All rights reserved. |
36 | * |
37 | * This code is derived from software contributed to Berkeley by |
38 | * William Jolitz. |
39 | * |
40 | * Redistribution and use in source and binary forms, with or without |
41 | * modification, are permitted provided that the following conditions |
42 | * are met: |
43 | * 1. Redistributions of source code must retain the above copyright |
44 | * notice, this list of conditions and the following disclaimer. |
45 | * 2. Redistributions in binary form must reproduce the above copyright |
46 | * notice, this list of conditions and the following disclaimer in the |
47 | * documentation and/or other materials provided with the distribution. |
48 | * 3. Neither the name of the University nor the names of its contributors |
49 | * may be used to endorse or promote products derived from this software |
50 | * without specific prior written permission. |
51 | * |
52 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
53 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
54 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
55 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
56 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
57 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
58 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
59 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
60 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
61 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
62 | * SUCH DAMAGE. |
63 | * |
64 | * @(#)machdep.c 7.4 (Berkeley) 6/3/91 |
65 | */ |
66 | |
67 | #include <sys/cdefs.h> |
68 | __KERNEL_RCSID(0, "$NetBSD: idt.c,v 1.4 2016/08/27 14:19:47 maxv Exp $" ); |
69 | |
70 | #include <sys/param.h> |
71 | #include <sys/systm.h> |
72 | #include <sys/mutex.h> |
73 | #include <sys/cpu.h> |
74 | #include <sys/atomic.h> |
75 | |
76 | #include <machine/segments.h> |
77 | |
78 | #if !defined(XEN) |
79 | |
80 | struct gate_descriptor *idt; |
81 | static char idt_allocmap[NIDT]; |
82 | |
83 | /* |
84 | * Allocate an IDT vector slot within the given range. |
85 | * cpu_lock will be held unless single threaded during early boot. |
86 | */ |
87 | int |
88 | idt_vec_alloc(int low, int high) |
89 | { |
90 | int vec; |
91 | |
92 | KASSERT(mutex_owned(&cpu_lock) || !mp_online); |
93 | |
94 | for (vec = low; vec <= high; vec++) { |
95 | if (idt_allocmap[vec] == 0) { |
96 | /* idt_vec_free() can be unlocked, so membar. */ |
97 | membar_sync(); |
98 | idt_allocmap[vec] = 1; |
99 | return vec; |
100 | } |
101 | } |
102 | return 0; |
103 | } |
104 | |
105 | void |
106 | idt_vec_reserve(int vec) |
107 | { |
108 | int result; |
109 | |
110 | KASSERT(mutex_owned(&cpu_lock) || !mp_online); |
111 | |
112 | result = idt_vec_alloc(vec, vec); |
113 | if (result != vec) { |
114 | panic("%s: failed to reserve vec %d" , __func__, vec); |
115 | } |
116 | } |
117 | |
118 | void |
119 | idt_vec_set(int vec, void (*function)(void)) |
120 | { |
121 | |
122 | KASSERT(mutex_owned(&cpu_lock) || !mp_online); |
123 | KASSERT(idt_allocmap[vec] == 1); |
124 | setgate(&idt[vec], function, 0, SDT_SYS386IGT, SEL_KPL, |
125 | GSEL(GCODE_SEL, SEL_KPL)); |
126 | } |
127 | |
128 | /* |
129 | * Free IDT vector. No locking required as release is atomic. |
130 | */ |
131 | void |
132 | idt_vec_free(int vec) |
133 | { |
134 | |
135 | unsetgate(&idt[vec]); |
136 | idt_allocmap[vec] = 0; |
137 | } |
138 | |
139 | #endif /* !defined(XEN) */ |
140 | |