1 /* $OpenBSD: tcb.h,v 1.4 2016/09/04 08:49:35 guenther Exp $ */ 2 3 /* 4 * Copyright (c) 2011 Philip Guenther <guenther@openbsd.org> 5 * 6 * Permission to use, copy, modify, and distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 #ifndef _MACHINE_TCB_H_ 20 #define _MACHINE_TCB_H_ 21 22 #ifdef _KERNEL 23 24 void *tcb_get(struct proc *_p); 25 void tcb_set(struct proc *_p, void *_newtcb); 26 27 #define TCB_GET(p) tcb_get(p) 28 #define TCB_SET(p, addr) tcb_set(p, addr) 29 30 #else /* _KERNEL */ 31 32 /* ELF TLS ABI calls for big TCB, with static TLS data at negative offsets */ 33 #define TLS_VARIANT 2 34 35 /* Read a slot from the TCB */ 36 static inline void * 37 __amd64_read_tcb(long offset) 38 { 39 void *val; 40 __asm__ ("movq %%fs:(%1),%0" : "=r" (val) : "r" (offset)); 41 return val; 42 } 43 44 /* Get a pointer to the TCB itself */ 45 #define TCB_GET() __amd64_read_tcb(0) 46 47 /* Setting the TCB pointer can only be done via syscall, so no TCB_SET() */ 48 49 #endif /* _KERNEL */ 50 #endif /* _MACHINE_TCB_H_ */ 51