2 * Copyright (c) 2006 The DragonFly Project. All rights reserved.
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
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
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
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.
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
35 #ifndef _MACHINE_THREAD_H_
36 #define _MACHINE_THREAD_H_
38 #include <machine/vframe.h>
39 #include <machine/npx.h>
42 unsigned int mtd_unused; /* used to be mtd_cpl */
43 union savefpu *mtd_savefpu; /* pointer to current fpu context */
44 struct vextframe mtd_savevext;
49 #define td_savefpu td_mach.mtd_savefpu
50 #define td_tls td_mach.mtd_savevext.vx_tls
51 #define td_savevext td_mach.mtd_savevext
54 * mycpu() retrieves the base of the current cpu's globaldata structure.
55 * Note that it is *NOT* volatile, meaning that the value may be cached by
56 * GCC. We have to force a dummy memory reference so gcc does not cache
57 * the gd pointer across a procedure call (which might block and cause us
58 * to wakeup on a different cpu).
60 * Also note that in DragonFly a thread can be preempted, but only by an
61 * interrupt thread and the original thread will resume after the
62 * interrupt thread finishes or blocks. A thread cannot move to another
63 * cpu preemptively or at all, in fact, while you are in the kernel, even
69 extern int __mycpu__dummy;
75 struct globaldata *gd;
77 __asm ("movl %%fs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy));
81 #define mycpu _get_mycpu()
84 #define mycpuid (_get_mycpu()->gd_cpuid)
90 * note: curthread is never NULL, but curproc can be. Also note that
91 * that only processes really use the PCB. Threads fill in some fields
92 * but mostly store contextual data on the stack and do not use (much of)
95 #define curthread mycpu->gd_curthread
96 #define curproc curthread->td_proc
100 #endif /* !_MACHINE_THREAD_H_ */