1 /* 2 * Copyright (c) 2003 Matt Dillon <dillon@backplane.com> 3 * Copyright (c) 2008 The DragonFly Project. 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * Machine independant code should not directly include this file. 28 */ 29 30 #ifndef _MACHINE_THREAD_H_ 31 #define _MACHINE_THREAD_H_ 32 33 #include <machine/segments.h> 34 35 struct md_thread { 36 unsigned int mtd_cpl; 37 union savefpu *mtd_savefpu; 38 struct savetls mtd_savetls; 39 }; 40 41 #ifdef _KERNEL 42 43 #define td_cpl td_mach.mtd_cpl 44 #define td_tls td_mach.mtd_savetls 45 #define td_savefpu td_mach.mtd_savefpu 46 47 /* 48 * mycpu() retrieves the base of the current cpu's globaldata structure. 49 * Note that it is *NOT* volatile, meaning that the value may be cached by 50 * GCC. We have to force a dummy memory reference so gcc does not cache 51 * the gd pointer across a procedure call (which might block and cause us 52 * to wakeup on a different cpu). 53 * 54 * Also note that in DragonFly a thread can be preempted, but it cannot 55 * move to another cpu preemptively so the 'gd' pointer is good until you 56 * block. 57 */ 58 59 struct globaldata; 60 61 extern int __mycpu__dummy; 62 63 static __inline 64 struct globaldata * 65 _get_mycpu(void) 66 { 67 struct globaldata *gd; 68 69 __asm ("movq %%gs:globaldata,%0" : "=r" (gd) : "m"(__mycpu__dummy)); 70 return(gd); 71 } 72 73 #define mycpu _get_mycpu() 74 #define mycpuid (_get_mycpu()->gd_cpuid) 75 76 /* 77 * note: curthread is never NULL, but curproc can be. Also note that 78 * in DragonFly, the current pcb is stored in the thread structure. 79 */ 80 #define curthread mycpu->gd_curthread 81 #define curproc curthread->td_proc 82 83 #endif /* _KERNEL */ 84 85 #endif /* !_MACHINE_THREAD_H_ */ 86