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/* $OpenBSD: tcb.h,v 1.2 2013/08/26 21:38:08 miod 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_
/*
* In userspace, register %r27 contains the address of the thread's TCB,
* and register %r26 contains the address of the thread's errno.
* It is the responsibility of the kernel to set %r27 to the proper value
* when creating the thread, while initialization of %r26 is done in
* userland within libpthread on a needed basis.
*/
#ifdef _KERNEL
#include <machine/reg.h>
#define TCB_GET(p) \
((void *)(p)->p_md.md_tf->tf_r[27])
#define TCB_SET(p, addr) \
((p)->p_md.md_tf->tf_r[27] = (register_t)(addr))
#else /* _KERNEL */
/*
* It is unknown whether the m88k ELF ABI mentions TLS. On m88k, since only
* unsigned offsets in (register + immediate offset) addressing is supported
* on all processors, it makes sense to use a small TCB, with static TLS data
* after it.
*/
#define TLS_VARIANT 1
#if defined(__GNUC__) && __GNUC__ > 4
struct thread_control_block;
__register__ struct thread_control_block *__tcb __asm__ ("%r27");
#define TCB_GET() (__tcb)
#define TCB_SET(tcb) ((__tcb) = (tcb))
#define TCB_GET_MEMBER(member) ((void *)(__tcb->member))
#else /* __GNUC__ > 4 */
#include <stddef.h> /* for offsetof */
/* Get a pointer to the TCB itself */
static inline void *
__m88k_get_tcb(void)
{
void *val;
__asm__ ("or %0,%%r27,%%r0" : "=r" (val));
return val;
}
/* Get the value of a specific member in the TCB */
static inline void *
__m88k_read_tcb(size_t offset)
{
void *val;
/* XXX the `offset' constraint ought to be "I" but this causes a warning */
__asm__ ("ld %0,%%r27,%1" : "=r" (val) : "r" (offset));
return val;
}
#define TCB_GET() __m88k_get_tcb()
#define TCB_SET(tcb) __asm __volatile("or %%r27,%0,%r0" : : "r" (tcb))
#define TCB_GET_MEMBER(member) \
__m88k_read_tcb(offsetof(struct thread_control_block, member))
#endif /* __GNUC__ > 4 */
#endif /* _KERNEL */
#endif /* _MACHINE_TCB_H_ */
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