1 /* $OpenBSD: tcb.h,v 1.6 2019/12/11 07:21:40 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 /*
23 * In userspace, register %r27 contains the address of the thread's TCB.
24 * It is the responsibility of the kernel to set %r27 to the proper value
25 * when creating the thread.
26 */
27
28 #ifdef _KERNEL
29
30 #include <machine/reg.h>
31
32 #define TCB_GET(p) \
33 ((void *)(p)->p_md.md_tf->tf_r[27])
34 #define TCB_SET(p, addr) \
35 ((p)->p_md.md_tf->tf_r[27] = (register_t)(addr))
36
37 #else /* _KERNEL */
38
39 /*
40 * It is unknown whether the m88k ELF ABI mentions TLS. On m88k, since only
41 * unsigned offsets in (register + immediate offset) addressing is supported
42 * on all processors, it makes sense to use a small TCB, with static TLS data
43 * after it.
44 */
45 #define TLS_VARIANT 1
46
47 #if defined(__GNUC__) && __GNUC__ >= 4
48
49 register void *__tcb __asm__ ("%r27");
50 #define TCB_GET() (__tcb)
51 #define TCB_SET(tcb) ((__tcb) = (tcb))
52
53 #else /* __GNUC__ >= 4 */
54
55 /* Get a pointer to the TCB itself */
56 static inline void *
__m88k_get_tcb(void)57 __m88k_get_tcb(void)
58 {
59 void *val;
60 __asm__ ("or %0,%%r27,%%r0" : "=r" (val));
61 return val;
62 }
63
64 #define TCB_GET() __m88k_get_tcb()
65 #define TCB_SET(tcb) __asm volatile("or %%r27,%0,%r0" : : "r" (tcb))
66
67 #endif /* __GNUC__ >= 4 */
68
69 #endif /* _KERNEL */
70 #endif /* _MACHINE_TCB_H_ */
71