2 * Copyright (c) 2003 Matt Dillon <dillon@backplane.com>, All rights reserved.
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * Machine independant code should not directly include this file.
27 * $DragonFly: src/sys/platform/pc32/include/thread.h,v 1.5 2003/07/10 04:47:53 dillon Exp $
30 #ifndef _MACHINE_THREAD_H_
31 #define _MACHINE_THREAD_H_
39 #define td_cpl td_mach.mtd_cpl
42 * mycpu() retrieves the base of the current cpu's globaldata structure.
43 * Note that it is *NOT* volatile, meaning that the value may be cached by
44 * GCC. We have to force a dummy memory reference so gcc does not cache
45 * the gd pointer across a procedure call (which might block and cause us
46 * to wakeup on a different cpu).
48 * Also note that in TurtleBSD a thread can be preempted, but it cannot
49 * move to another cpu preemptively so the 'gd' pointer is good until you
55 extern int __mycpu__dummy;
61 struct globaldata *gd;
63 __asm ("movl %%fs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy));
67 #define mycpu _get_mycpu()
70 * note: curthread is never NULL, but curproc can be. Also note that
71 * in Turtle, the current pcb is stored in the thread structure.
73 #define curthread mycpu->gd_curthread
74 #define curproc curthread->td_proc
78 #endif /* !_MACHINE_THREAD_H_ */