1 /* SPDX-License-Identifier: GPL-2.0 */
2 /*
3 * locks.S: SMP low-level lock primitives on S
4 *
5 * Copyright (C) 1996 David S. Miller (davem@c
6 * Copyright (C) 1998 Anton Blanchard (anton@p
7 * Copyright (C) 1998 Jakub Jelinek (jj@ultr
8 */
9
10 #include <linux/export.h>
11 #include <asm/ptrace.h>
12 #include <asm/psr.h>
13 #include <asm/smp.h>
14 #include <asm/spinlock.h>
15
16 .text
17 .align 4
18
19 /* Read/writer locks, as usual this is
20 * as fast as possible.
21 */
22
23 /* caches... */
24 ___rw_read_enter_spin_on_wlock:
25 orcc %g2, 0x0, %g0
26 be,a ___rw_read_enter
27 ldstub [%g1 + 3], %g2
28 b ___rw_read_enter_spin_on_wlock
29 ldub [%g1 + 3], %g2
30 ___rw_read_try_spin_on_wlock:
31 andcc %g2, 0xff, %g0
32 be,a ___rw_read_try
33 ldstub [%g1 + 3], %g2
34 xnorcc %g2, 0x0, %o0 /* if g2 is ~0
35 bne,a ___rw_read_enter_spin_on_wlock
36 ld [%g1], %g2
37 retl
38 mov %g4, %o7
39 ___rw_read_exit_spin_on_wlock:
40 orcc %g2, 0x0, %g0
41 be,a ___rw_read_exit
42 ldstub [%g1 + 3], %g2
43 b ___rw_read_exit_spin_on_wlock
44 ldub [%g1 + 3], %g2
45 ___rw_write_enter_spin_on_wlock:
46 orcc %g2, 0x0, %g0
47 be,a ___rw_write_enter
48 ldstub [%g1 + 3], %g2
49 b ___rw_write_enter_spin_on_wloc
50 ld [%g1], %g2
51
52 .globl ___rw_read_enter
53 EXPORT_SYMBOL(___rw_read_enter)
54 ___rw_read_enter:
55 orcc %g2, 0x0, %g0
56 bne,a ___rw_read_enter_spin_on_wlock
57 ldub [%g1 + 3], %g2
58 ld [%g1], %g2
59 add %g2, 1, %g2
60 st %g2, [%g1]
61 retl
62 mov %g4, %o7
63
64 .globl ___rw_read_exit
65 EXPORT_SYMBOL(___rw_read_exit)
66 ___rw_read_exit:
67 orcc %g2, 0x0, %g0
68 bne,a ___rw_read_exit_spin_on_wlock
69 ldub [%g1 + 3], %g2
70 ld [%g1], %g2
71 sub %g2, 0x1ff, %g2
72 st %g2, [%g1]
73 retl
74 mov %g4, %o7
75
76 .globl ___rw_read_try
77 EXPORT_SYMBOL(___rw_read_try)
78 ___rw_read_try:
79 orcc %g2, 0x0, %g0
80 bne ___rw_read_try_spin_on_wlock
81 ld [%g1], %g2
82 add %g2, 1, %g2
83 st %g2, [%g1]
84 set 1, %o1
85 retl
86 mov %g4, %o7
87
88 .globl ___rw_write_enter
89 EXPORT_SYMBOL(___rw_write_enter)
90 ___rw_write_enter:
91 orcc %g2, 0x0, %g0
92 bne ___rw_write_enter_spin_on_wloc
93 ld [%g1], %g2
94 andncc %g2, 0xff, %g0
95 bne,a ___rw_write_enter_spin_on_wloc
96 stb %g0, [%g1 + 3]
97 retl
98 mov %g4, %o7
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