1 /* 2 * Copyright (c) 2006 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 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 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 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 32 * SUCH DAMAGE. 33 * 34 * $DragonFly: src/sys/platform/vkernel/include/thread.h,v 1.2 2007/01/08 03:33:43 dillon Exp $ 35 */ 36 37 #ifndef _MACHINE_THREAD_H_ 38 #define _MACHINE_THREAD_H_ 39 40 #ifndef _MACHINE_VFRAME_H_ 41 #include <machine/vframe.h> 42 #endif 43 #ifndef _MACHINE_NPX_H_ 44 #include <machine/npx.h> 45 #endif 46 47 struct md_thread { 48 unsigned int mtd_unused; /* used to be mtd_cpl */ 49 union savefpu *mtd_savefpu; /* pointer to current fpu context */ 50 struct vextframe mtd_savevext; 51 }; 52 53 #ifdef _KERNEL 54 55 #define td_savefpu td_mach.mtd_savefpu 56 #define td_tls td_mach.mtd_savevext.vx_tls 57 #define td_savevext td_mach.mtd_savevext 58 59 /* 60 * mycpu() retrieves the base of the current cpu's globaldata structure. 61 * Note that it is *NOT* volatile, meaning that the value may be cached by 62 * GCC. We have to force a dummy memory reference so gcc does not cache 63 * the gd pointer across a procedure call (which might block and cause us 64 * to wakeup on a different cpu). 65 * 66 * Also note that in DragonFly a thread can be preempted, but only by an 67 * interrupt thread and the original thread will resume after the 68 * interrupt thread finishes or blocks. A thread cannot move to another 69 * cpu preemptively or at all, in fact, while you are in the kernel, even 70 * if you block. 71 */ 72 73 struct globaldata; 74 75 extern int __mycpu__dummy; 76 77 static __inline 78 struct globaldata * 79 _get_mycpu(void) 80 { 81 struct globaldata *gd; 82 83 __asm ("movq %%gs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy)); 84 return(gd); 85 } 86 87 #define mycpu _get_mycpu() 88 89 #ifdef SMP 90 #define mycpuid (_get_mycpu()->gd_cpuid) 91 #else 92 #define mycpuid 0 93 #endif 94 95 /* 96 * note: curthread is never NULL, but curproc can be. Also note that 97 * that only processes really use the PCB. Threads fill in some fields 98 * but mostly store contextual data on the stack and do not use (much of) 99 * the PCB. 100 */ 101 #define curthread mycpu->gd_curthread 102 #define curproc curthread->td_proc 103 104 #endif /* _KERNEL */ 105 106 #endif /* !_MACHINE_THREAD_H_ */ 107