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 35 #ifndef _MACHINE_THREAD_H_ 36 #define _MACHINE_THREAD_H_ 37 38 #include <machine/vframe.h> 39 #include <machine/npx.h> 40 41 struct md_thread { 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; 45 }; 46 47 #ifdef _KERNEL 48 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 52 53 /* 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). 59 * 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 64 * if you block. 65 */ 66 67 struct globaldata; 68 69 extern int __mycpu__dummy; 70 71 static __inline 72 struct globaldata * 73 _get_mycpu(void) 74 { 75 struct globaldata *gd; 76 77 __asm ("movq %%gs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy)); 78 return(gd); 79 } 80 81 #define mycpu _get_mycpu() 82 #define mycpuid (_get_mycpu()->gd_cpuid) 83 84 /* 85 * note: curthread is never NULL, but curproc can be. Also note that 86 * that only processes really use the PCB. Threads fill in some fields 87 * but mostly store contextual data on the stack and do not use (much of) 88 * the PCB. 89 */ 90 #define curthread mycpu->gd_curthread 91 #define curproc curthread->td_proc 92 93 #endif /* _KERNEL */ 94 95 #endif /* !_MACHINE_THREAD_H_ */ 96