summaryrefslogtreecommitdiffstats
path: root/arch/mips/include/asm/cmpxchg.h
blob: eefcaa363a875f3f0a0f0c727bcd0cefe2e5a701 (plain)
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
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2003, 06, 07 by Ralf Baechle (ralf@linux-mips.org)
 */
#ifndef __ASM_CMPXCHG_H
#define __ASM_CMPXCHG_H

#include <linux/bug.h>
#include <linux/irqflags.h>
#include <asm/war.h>

static inline unsigned long __xchg_u32(volatile int * m, unsigned int val)
{
	__u32 retval;

	smp_mb__before_llsc();

	if (kernel_uses_llsc && R10000_LLSC_WAR) {
		unsigned long dummy;

		__asm__ __volatile__(
		"	.set	arch=r4000				\n"
		"1:	ll	%0, %3			# xchg_u32	\n"
		"	.set	mips0					\n"
		"	move	%2, %z4					\n"
		"	.set	arch=r4000				\n"
		"	sc	%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
		: "R" (*m), "Jr" (val)
		: "memory");
	} else if (kernel_uses_llsc) {
		unsigned long dummy;

		do {
			__asm__ __volatile__(
			"	.set	arch=r4000			\n"
			"	ll	%0, %3		# xchg_u32	\n"
			"	.set	mips0				\n"
			"	move	%2, %z4				\n"
			"	.set	arch=r4000			\n"
			"	sc	%2, %1				\n"
			"	.set	mips0				\n"
			: "=&r" (retval), "=m" (*m), "=&r" (dummy)
			: "R" (*m), "Jr" (val)
			: "memory");
		} while (unlikely(!dummy));
	} else {
		unsigned long flags;

		raw_local_irq_save(flags);
		retval = *m;
		*m = val;
		raw_local_irq_restore(flags);	/* implies memory barrier  */
	}

	smp_llsc_mb();

	return retval;
}

#ifdef CONFIG_64BIT
static inline __u64 __xchg_u64(volatile __u64 * m, __u64 val)
{
	__u64 retval;

	smp_mb__before_llsc();

	if (kernel_uses_llsc && R10000_LLSC_WAR) {
		unsigned long dummy;

		__asm__ __volatile__(
		"	.set	arch=r4000				\n"
		"1:	lld	%0, %3			# xchg_u64	\n"
		"	move	%2, %z4					\n"
		"	scd	%2, %1					\n"
		"	beqzl	%2, 1b					\n"
		"	.set	mips0					\n"
		: "=&r" (retval), "=m" (*m), "=&r" (dummy)
		: "R" (*m), "Jr" (val)
		: "memory");
	} else if (kernel_uses_llsc) {
		unsigned long dummy;

		do {
			__asm__ __volatile__(
			"	.set	arch=r4000			\n"
			"	lld	%0, %3		# xchg_u64	\n"
			"	move	%2, %z4				\n"
			"	scd	%2, %1				\n"
			"	.set	mips0				\n"
			: "=&r" (retval), "=m" (*m), "=&r" (dummy)
			: "R" (*m), "Jr" (val)
			: "memory");
		} while (unlikely(!dummy));
	} else {
		unsigned long flags;

		raw_local_irq_save(flags);
		retval = *m;
		*m = val;
		raw_local_irq_restore(flags);	/* implies memory barrier  */
	}

	smp_llsc_mb();

	return retval;
}
#else
extern __u64 __xchg_u64_unsupported_on_32bit_kernels(volatile __u64 * m, __u64 val);
#define __xchg_u64 __xchg_u64_unsupported_on_32bit_kernels
#endif

static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
{
	switch (size) {
	case 4:
		return __xchg_u32(ptr, x);
	case 8:
		return __xchg_u64(ptr, x);
	}

	return x;
}

#define xchg(ptr, x)							\
({									\
	BUILD_BUG_ON(sizeof(*(ptr)) & ~0xc);				\
									\
	((__typeof__(*(ptr)))						\
		__xchg((unsigned long)(x), (ptr), sizeof(*(ptr))));	\
})

#define __HAVE_ARCH_CMPXCHG 1

#define __cmpxchg_asm(ld, st, m, old, new)				\
({									\
	__typeof(*(m)) __ret;						\
									\
	if (kernel_uses_llsc && R10000_LLSC_WAR) {			\
		__asm__ __volatile__(					\
		"	.set	push				\n"	\
		"	.set	noat				\n"	\
		"	.set	arch=r4000			\n"	\
		"1:	" ld "	%0, %2		# __cmpxchg_asm \n"	\
		"	bne	%0, %z3, 2f			\n"	\
		"	.set	mips0				\n"	\
		"	move	$1, %z4				\n"	\
		"	.set	arch=r4000			\n"	\
		"	" st "	$1, %1				\n"	\
		"	beqzl	$1, 1b				\n"	\
		"2:						\n"	\
		"	.set	pop				\n"	\
		: "=&r" (__ret), "=R" (*m)				\
		: "R" (*m), "Jr" (old), "Jr" (new)			\
		: "memory");						\
	} else if (kernel_uses_llsc) {					\
		__asm__ __volatile__(					\
		"	.set	push				\n"	\
		"	.set	noat				\n"	\
		"	.set	arch=r4000			\n"	\
		"1:	" ld "	%0, %2		# __cmpxchg_asm \n"	\
		"	bne	%0, %z3, 2f			\n"	\
		"	.set	mips0				\n"	\
		"	move	$1, %z4				\n"	\
		"	.set	arch=r4000			\n"	\
		"	" st "	$1, %1				\n"	\
		"	beqz	$1, 1b				\n"	\
		"	.set	pop				\n"	\
		"2:						\n"	\
		: "=&r" (__ret), "=R" (*m)				\
		: "R" (*m), "Jr" (old), "Jr" (new)			\
		: "memory");						\
	} else {							\
		unsigned long __flags;					\
									\
		raw_local_irq_save(__flags);				\
		__ret = *m;						\
		if (__ret == old)					\
			*m = new;					\
		raw_local_irq_restore(__flags);				\
	}								\
									\
	__ret;								\
})

/*
 * This function doesn't exist, so you'll get a linker error
 * if something tries to do an invalid cmpxchg().
 */
extern void __cmpxchg_called_with_bad_pointer(void);

#define __cmpxchg(ptr, old, new, pre_barrier, post_barrier)		\
({									\
	__typeof__(ptr) __ptr = (ptr);					\
	__typeof__(*(ptr)) __old = (old);				\
	__typeof__(*(ptr)) __new = (new);				\
	__typeof__(*(ptr)) __res = 0;					\
									\
	pre_barrier;							\
									\
	switch (sizeof(*(__ptr))) {					\
	case 4:								\
		__res = __cmpxchg_asm("ll", "sc", __ptr, __old, __new); \
		break;							\
	case 8:								\
		if (sizeof(long) == 8) {				\
			__res = __cmpxchg_asm("lld", "scd", __ptr,	\
					   __old, __new);		\
			break;						\
		}							\
	default:							\
		__cmpxchg_called_with_bad_pointer();			\
		break;							\
	}								\
									\
	post_barrier;							\
									\
	__res;								\
})

#define cmpxchg(ptr, old, new)		__cmpxchg(ptr, old, new, smp_mb__before_llsc(), smp_llsc_mb())
#define cmpxchg_local(ptr, old, new)	__cmpxchg(ptr, old, new, , )

#define cmpxchg64(ptr, o, n)						\
  ({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	cmpxchg((ptr), (o), (n));					\
  })

#ifdef CONFIG_64BIT
#define cmpxchg64_local(ptr, o, n)					\
  ({									\
	BUILD_BUG_ON(sizeof(*(ptr)) != 8);				\
	cmpxchg_local((ptr), (o), (n));					\
  })
#else
#include <asm-generic/cmpxchg-local.h>
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#endif

#endif /* __ASM_CMPXCHG_H */