2 * Copyright (c) 1999 Luoqi Chen <luoqi@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * $FreeBSD: src/sys/i386/include/globals.h,v 1.5.2.1 2000/05/16 06:58:10 dillon Exp $
27 * $DragonFly: src/sys/platform/pc32/include/Attic/globals.h,v 1.7 2003/06/20 02:09:54 dillon Exp $
30 #ifndef _MACHINE_GLOBALS_H_
31 #define _MACHINE_GLOBALS_H_
36 * mycpu() retrieves the base of the current cpu's globaldata structure.
37 * Note that it is *NOT* volatile, meaning that the value may be cached by
38 * GCC. We have to force a dummy memory reference so gcc does not cache
39 * the gd pointer across a procedure call (which might block and cause us
40 * to wakeup on a different cpu).
42 * Also note that in TurtleBSD a thread can be preempted, but it cannot
43 * move to another cpu preemptively so the 'gd' pointer is good until you
46 #if defined(SMP) || defined(KLD_MODULE) || defined(ACTUALLY_LKM_NOT_KERNEL)
48 extern int __mycpu__dummy;
54 struct globaldata *gd;
56 __asm ("movl %%fs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy));
60 #define mycpu _get_mycpu()
64 #define mycpu (&CPU_prvspace[0].globaldata)
69 * note: curthread is never NULL, but curproc can be. Also note that
70 * in Turtle, the current pcb is stored in the thread structure.
72 #define curthread (mycpu->gd_curthread)
73 #define curproc (curthread->td_proc)
78 #endif /* !_MACHINE_GLOBALS_H_ */