1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
|
/* $OpenBSD: lock.h,v 1.11 2017/05/27 15:11:03 mpi Exp $ */
/*
* Copyright (c) 2012 Mark Kettenis <kettenis@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_LOCK_H_
#define _MACHINE_LOCK_H_
#ifdef _KERNEL
/*
* On processors with multiple threads we force a thread switch.
*
* On UltraSPARC T2 and its successors, the optimal way to do this
* seems to be to do three nop reads of %ccr. This works on
* UltraSPARC T1 as well, even though three nop casx operations seem
* to be slightly more optimal. Since these instructions are
* effectively nops, executing them on earlier non-CMT processors is
* harmless, so we make this the default.
*
* On SPARC T4 and later, we can use the processor-specific pause
* instruction.
*
* On SPARC64 VI and its successors we execute the processor-specific
* sleep instruction.
*/
#define SPINLOCK_SPIN_HOOK \
do { \
__asm volatile( \
"999: rd %%ccr, %%g0 \n" \
" rd %%ccr, %%g0 \n" \
" rd %%ccr, %%g0 \n" \
" .section .sun4v_pause_patch, \"ax\" \n" \
" .word 999b \n" \
" .word 0xb7802080 ! pause 128 \n" \
" .word 999b + 4 \n" \
" nop \n" \
" .word 999b + 8 \n" \
" nop \n" \
" .previous \n" \
" .section .sun4u_mtp_patch, \"ax\" \n" \
" .word 999b \n" \
" .word 0x81b01060 ! sleep \n" \
" .word 999b + 4 \n" \
" nop \n" \
" .word 999b + 8 \n" \
" nop \n" \
" .previous \n" \
: : : "memory"); \
} while (0)
#endif /* _KERNEL */
#endif /* _MACHINE_LOCK_H_ */
|
