xref: /linux/arch/mips/lib/mips-atomic.c (revision 3932b9ca55b0be314a36d3e84faff3e823c081f5)
1 /*
2  * This file is subject to the terms and conditions of the GNU General Public
3  * License.  See the file "COPYING" in the main directory of this archive
4  * for more details.
5  *
6  * Copyright (C) 1994, 95, 96, 97, 98, 99, 2003 by Ralf Baechle
7  * Copyright (C) 1996 by Paul M. Antoine
8  * Copyright (C) 1999 Silicon Graphics
9  * Copyright (C) 2000 MIPS Technologies, Inc.
10  */
11 #include <asm/irqflags.h>
12 #include <asm/hazards.h>
13 #include <linux/compiler.h>
14 #include <linux/preempt.h>
15 #include <linux/export.h>
16 #include <linux/stringify.h>
17 
18 #ifndef CONFIG_CPU_MIPSR2
19 
20 /*
21  * For cli() we have to insert nops to make sure that the new value
22  * has actually arrived in the status register before the end of this
23  * macro.
24  * R4000/R4400 need three nops, the R4600 two nops and the R10000 needs
25  * no nops at all.
26  */
27 /*
28  * For TX49, operating only IE bit is not enough.
29  *
30  * If mfc0 $12 follows store and the mfc0 is last instruction of a
31  * page and fetching the next instruction causes TLB miss, the result
32  * of the mfc0 might wrongly contain EXL bit.
33  *
34  * ERT-TX49H2-027, ERT-TX49H3-012, ERT-TX49HL3-006, ERT-TX49H4-008
35  *
36  * Workaround: mask EXL bit of the result or place a nop before mfc0.
37  */
38 notrace void arch_local_irq_disable(void)
39 {
40 	preempt_disable();
41 
42 	__asm__ __volatile__(
43 	"	.set	push						\n"
44 	"	.set	noat						\n"
45 #if   defined(CONFIG_CPU_MIPSR2)
46 	/* see irqflags.h for inline function */
47 #else
48 	"	mfc0	$1,$12						\n"
49 	"	ori	$1,0x1f						\n"
50 	"	xori	$1,0x1f						\n"
51 	"	.set	noreorder					\n"
52 	"	mtc0	$1,$12						\n"
53 #endif
54 	"	" __stringify(__irq_disable_hazard) "			\n"
55 	"	.set	pop						\n"
56 	: /* no outputs */
57 	: /* no inputs */
58 	: "memory");
59 
60 	preempt_enable();
61 }
62 EXPORT_SYMBOL(arch_local_irq_disable);
63 
64 
65 notrace unsigned long arch_local_irq_save(void)
66 {
67 	unsigned long flags;
68 
69 	preempt_disable();
70 
71 	__asm__ __volatile__(
72 	"	.set	push						\n"
73 	"	.set	reorder						\n"
74 	"	.set	noat						\n"
75 #if   defined(CONFIG_CPU_MIPSR2)
76 	/* see irqflags.h for inline function */
77 #else
78 	"	mfc0	%[flags], $12					\n"
79 	"	ori	$1, %[flags], 0x1f				\n"
80 	"	xori	$1, 0x1f					\n"
81 	"	.set	noreorder					\n"
82 	"	mtc0	$1, $12						\n"
83 #endif
84 	"	" __stringify(__irq_disable_hazard) "			\n"
85 	"	.set	pop						\n"
86 	: [flags] "=r" (flags)
87 	: /* no inputs */
88 	: "memory");
89 
90 	preempt_enable();
91 
92 	return flags;
93 }
94 EXPORT_SYMBOL(arch_local_irq_save);
95 
96 notrace void arch_local_irq_restore(unsigned long flags)
97 {
98 	unsigned long __tmp1;
99 
100 	preempt_disable();
101 
102 	__asm__ __volatile__(
103 	"	.set	push						\n"
104 	"	.set	noreorder					\n"
105 	"	.set	noat						\n"
106 #if   defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
107 	/* see irqflags.h for inline function */
108 #elif defined(CONFIG_CPU_MIPSR2)
109 	/* see irqflags.h for inline function */
110 #else
111 	"	mfc0	$1, $12						\n"
112 	"	andi	%[flags], 1					\n"
113 	"	ori	$1, 0x1f					\n"
114 	"	xori	$1, 0x1f					\n"
115 	"	or	%[flags], $1					\n"
116 	"	mtc0	%[flags], $12					\n"
117 #endif
118 	"	" __stringify(__irq_disable_hazard) "			\n"
119 	"	.set	pop						\n"
120 	: [flags] "=r" (__tmp1)
121 	: "0" (flags)
122 	: "memory");
123 
124 	preempt_enable();
125 }
126 EXPORT_SYMBOL(arch_local_irq_restore);
127 
128 
129 notrace void __arch_local_irq_restore(unsigned long flags)
130 {
131 	unsigned long __tmp1;
132 
133 	preempt_disable();
134 
135 	__asm__ __volatile__(
136 	"	.set	push						\n"
137 	"	.set	noreorder					\n"
138 	"	.set	noat						\n"
139 #if   defined(CONFIG_CPU_MIPSR2) && defined(CONFIG_IRQ_CPU)
140 	/* see irqflags.h for inline function */
141 #elif defined(CONFIG_CPU_MIPSR2)
142 	/* see irqflags.h for inline function */
143 #else
144 	"	mfc0	$1, $12						\n"
145 	"	andi	%[flags], 1					\n"
146 	"	ori	$1, 0x1f					\n"
147 	"	xori	$1, 0x1f					\n"
148 	"	or	%[flags], $1					\n"
149 	"	mtc0	%[flags], $12					\n"
150 #endif
151 	"	" __stringify(__irq_disable_hazard) "			\n"
152 	"	.set	pop						\n"
153 	: [flags] "=r" (__tmp1)
154 	: "0" (flags)
155 	: "memory");
156 
157 	preempt_enable();
158 }
159 EXPORT_SYMBOL(__arch_local_irq_restore);
160 
161 #endif /* !CONFIG_CPU_MIPSR2 */
162