kernel: Make SMP support default (and non-optional).
[dragonfly.git] / sys / platform / pc32 / include / thread.h
CommitLineData
f1d1c3fa 1/*
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2 * Copyright (c) 2003,2004 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
6 *
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7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
8c10bfcf 10 *
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11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
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14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 * 3. Neither the name of The DragonFly Project nor the names of its
18 * contributors may be used to endorse or promote products derived
19 * from this software without specific, prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
85100692 32 * SUCH DAMAGE.
8c10bfcf 33 *
85100692 34 * Machine independant code should not directly include this file.
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35 */
36
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37#ifndef _MACHINE_THREAD_H_
38#define _MACHINE_THREAD_H_
39
f8334305 40#include <machine/segments.h>
806bf111 41
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42union savefpu;
43
85100692 44struct md_thread {
38787eef 45 unsigned int mtd_unused; /* used to be mtd_cpl */
65d6ce10 46 union savefpu *mtd_savefpu;
4e7c41c5 47 struct savetls mtd_savetls;
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48};
49
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50#ifdef _KERNEL
51
65d6ce10 52#define td_savefpu td_mach.mtd_savefpu
4e7c41c5 53#define td_tls td_mach.mtd_savetls
8f41e33b 54
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55/*
56 * mycpu() retrieves the base of the current cpu's globaldata structure.
57 * Note that it is *NOT* volatile, meaning that the value may be cached by
58 * GCC. We have to force a dummy memory reference so gcc does not cache
59 * the gd pointer across a procedure call (which might block and cause us
60 * to wakeup on a different cpu).
61 *
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62 * Also note that in DragonFly a thread can be preempted, but only by an
63 * interrupt thread and the original thread will resume after the
64 * interrupt thread finishes or blocks. A thread cannot move to another
65 * cpu preemptively or at all, in fact, while you are in the kernel, even
66 * if you block.
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67 */
68
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69struct globaldata;
70
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71extern int __mycpu__dummy;
72
73static __inline
74struct globaldata *
75_get_mycpu(void)
76{
77 struct globaldata *gd;
78
79 __asm ("movl %%fs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy));
80 return(gd);
81}
82
e36ff5a2 83#define mycpu _get_mycpu()
ecdefdda 84#define mycpuid (_get_mycpu()->gd_cpuid)
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85
86/*
87 * note: curthread is never NULL, but curproc can be. Also note that
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88 * that only processes really use the PCB. Threads fill in some fields
89 * but mostly store contextual data on the stack and do not use (much of)
90 * the PCB.
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91 */
92#define curthread mycpu->gd_curthread
93#define curproc curthread->td_proc
94
95#endif /* _KERNEL */
96
97#endif /* !_MACHINE_THREAD_H_ */