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/* $OpenBSD: tcb.h,v 1.6 2017/10/13 05:14:02 guenther Exp $ */
/*
* Copyright (c) 2011 Philip Guenther <guenther@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef _MACHINE_TCB_H_
#define _MACHINE_TCB_H_
#ifdef _KERNEL
void *tcb_get(struct proc *_p);
void tcb_set(struct proc *_p, void *_newtcb);
#define TCB_GET(p) tcb_get(p)
#define TCB_SET(p, addr) tcb_set(p, addr)
/* address must be in canonical form; requiring lower-half is okay */
#define TCB_INVALID(addr) ((u_long)(addr) > 0x00007fffffffffff)
#else /* _KERNEL */
/* ELF TLS ABI calls for big TCB, with static TLS data at negative offsets */
#define TLS_VARIANT 2
/* Read a slot from the TCB */
static inline void *
__amd64_read_tcb(long offset)
{
void *val;
__asm__ ("movq %%fs:(%1),%0" : "=r" (val) : "r" (offset));
return val;
}
/* Get a pointer to the TCB itself */
#define TCB_GET() __amd64_read_tcb(0)
/* Setting the TCB pointer can only be done via syscall, so no TCB_SET() */
#endif /* _KERNEL */
#endif /* _MACHINE_TCB_H_ */
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