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1/*
2 * Atomic operations that C can't guarantee us. Useful for
3 * resource counting etc..
4 *
5 * But use these as seldom as possible since they are much more slower
6 * than regular operations.
7 *
8 * This file is subject to the terms and conditions of the GNU General Public
9 * License. See the file "COPYING" in the main directory of this archive
10 * for more details.
11 *
12 * Copyright (C) 1996, 97, 99, 2000, 03, 04, 06 by Ralf Baechle
13 */
14#ifndef _ASM_ATOMIC_H
15#define _ASM_ATOMIC_H
16
17#include <linux/irqflags.h>
18#include <linux/types.h>
19#include <asm/barrier.h>
20#include <asm/compiler.h>
21#include <asm/cpu-features.h>
22#include <asm/cmpxchg.h>
23#include <asm/llsc.h>
24#include <asm/sync.h>
25#include <asm/war.h>
26
27#define ATOMIC_OPS(pfx, type) \
28static __always_inline type pfx##_read(const pfx##_t *v) \
29{ \
30 return READ_ONCE(v->counter); \
31} \
32 \
33static __always_inline void pfx##_set(pfx##_t *v, type i) \
34{ \
35 WRITE_ONCE(v->counter, i); \
36} \
37 \
38static __always_inline type pfx##_cmpxchg(pfx##_t *v, type o, type n) \
39{ \
40 return cmpxchg(&v->counter, o, n); \
41} \
42 \
43static __always_inline type pfx##_xchg(pfx##_t *v, type n) \
44{ \
45 return xchg(&v->counter, n); \
46}
47
48ATOMIC_OPS(atomic, int)
49
50#ifdef CONFIG_64BIT
51# define ATOMIC64_INIT(i) { (i) }
52ATOMIC_OPS(atomic64, s64)
53#endif
54
55#define ATOMIC_OP(pfx, op, type, c_op, asm_op, ll, sc) \
56static __inline__ void pfx##_##op(type i, pfx##_t * v) \
57{ \
58 type temp; \
59 \
60 if (!kernel_uses_llsc) { \
61 unsigned long flags; \
62 \
63 raw_local_irq_save(flags); \
64 v->counter c_op i; \
65 raw_local_irq_restore(flags); \
66 return; \
67 } \
68 \
69 __asm__ __volatile__( \
70 " .set push \n" \
71 " .set " MIPS_ISA_LEVEL " \n" \
72 " " __SYNC(full, loongson3_war) " \n" \
73 "1: " #ll " %0, %1 # " #pfx "_" #op " \n" \
74 " " #asm_op " %0, %2 \n" \
75 " " #sc " %0, %1 \n" \
76 "\t" __SC_BEQZ "%0, 1b \n" \
77 " .set pop \n" \
78 : "=&r" (temp), "+" GCC_OFF_SMALL_ASM() (v->counter) \
79 : "Ir" (i) : __LLSC_CLOBBER); \
80}
81
82#define ATOMIC_OP_RETURN(pfx, op, type, c_op, asm_op, ll, sc) \
83static __inline__ type pfx##_##op##_return_relaxed(type i, pfx##_t * v) \
84{ \
85 type temp, result; \
86 \
87 if (!kernel_uses_llsc) { \
88 unsigned long flags; \
89 \
90 raw_local_irq_save(flags); \
91 result = v->counter; \
92 result c_op i; \
93 v->counter = result; \
94 raw_local_irq_restore(flags); \
95 return result; \
96 } \
97 \
98 __asm__ __volatile__( \
99 " .set push \n" \
100 " .set " MIPS_ISA_LEVEL " \n" \
101 " " __SYNC(full, loongson3_war) " \n" \
102 "1: " #ll " %1, %2 # " #pfx "_" #op "_return\n" \
103 " " #asm_op " %0, %1, %3 \n" \
104 " " #sc " %0, %2 \n" \
105 "\t" __SC_BEQZ "%0, 1b \n" \
106 " " #asm_op " %0, %1, %3 \n" \
107 " .set pop \n" \
108 : "=&r" (result), "=&r" (temp), \
109 "+" GCC_OFF_SMALL_ASM() (v->counter) \
110 : "Ir" (i) : __LLSC_CLOBBER); \
111 \
112 return result; \
113}
114
115#define ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc) \
116static __inline__ type pfx##_fetch_##op##_relaxed(type i, pfx##_t * v) \
117{ \
118 int temp, result; \
119 \
120 if (!kernel_uses_llsc) { \
121 unsigned long flags; \
122 \
123 raw_local_irq_save(flags); \
124 result = v->counter; \
125 v->counter c_op i; \
126 raw_local_irq_restore(flags); \
127 return result; \
128 } \
129 \
130 __asm__ __volatile__( \
131 " .set push \n" \
132 " .set " MIPS_ISA_LEVEL " \n" \
133 " " __SYNC(full, loongson3_war) " \n" \
134 "1: " #ll " %1, %2 # " #pfx "_fetch_" #op "\n" \
135 " " #asm_op " %0, %1, %3 \n" \
136 " " #sc " %0, %2 \n" \
137 "\t" __SC_BEQZ "%0, 1b \n" \
138 " .set pop \n" \
139 " move %0, %1 \n" \
140 : "=&r" (result), "=&r" (temp), \
141 "+" GCC_OFF_SMALL_ASM() (v->counter) \
142 : "Ir" (i) : __LLSC_CLOBBER); \
143 \
144 return result; \
145}
146
147#undef ATOMIC_OPS
148#define ATOMIC_OPS(pfx, op, type, c_op, asm_op, ll, sc) \
149 ATOMIC_OP(pfx, op, type, c_op, asm_op, ll, sc) \
150 ATOMIC_OP_RETURN(pfx, op, type, c_op, asm_op, ll, sc) \
151 ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc)
152
153ATOMIC_OPS(atomic, add, int, +=, addu, ll, sc)
154ATOMIC_OPS(atomic, sub, int, -=, subu, ll, sc)
155
156#define atomic_add_return_relaxed atomic_add_return_relaxed
157#define atomic_sub_return_relaxed atomic_sub_return_relaxed
158#define atomic_fetch_add_relaxed atomic_fetch_add_relaxed
159#define atomic_fetch_sub_relaxed atomic_fetch_sub_relaxed
160
161#ifdef CONFIG_64BIT
162ATOMIC_OPS(atomic64, add, s64, +=, daddu, lld, scd)
163ATOMIC_OPS(atomic64, sub, s64, -=, dsubu, lld, scd)
164# define atomic64_add_return_relaxed atomic64_add_return_relaxed
165# define atomic64_sub_return_relaxed atomic64_sub_return_relaxed
166# define atomic64_fetch_add_relaxed atomic64_fetch_add_relaxed
167# define atomic64_fetch_sub_relaxed atomic64_fetch_sub_relaxed
168#endif /* CONFIG_64BIT */
169
170#undef ATOMIC_OPS
171#define ATOMIC_OPS(pfx, op, type, c_op, asm_op, ll, sc) \
172 ATOMIC_OP(pfx, op, type, c_op, asm_op, ll, sc) \
173 ATOMIC_FETCH_OP(pfx, op, type, c_op, asm_op, ll, sc)
174
175ATOMIC_OPS(atomic, and, int, &=, and, ll, sc)
176ATOMIC_OPS(atomic, or, int, |=, or, ll, sc)
177ATOMIC_OPS(atomic, xor, int, ^=, xor, ll, sc)
178
179#define atomic_fetch_and_relaxed atomic_fetch_and_relaxed
180#define atomic_fetch_or_relaxed atomic_fetch_or_relaxed
181#define atomic_fetch_xor_relaxed atomic_fetch_xor_relaxed
182
183#ifdef CONFIG_64BIT
184ATOMIC_OPS(atomic64, and, s64, &=, and, lld, scd)
185ATOMIC_OPS(atomic64, or, s64, |=, or, lld, scd)
186ATOMIC_OPS(atomic64, xor, s64, ^=, xor, lld, scd)
187# define atomic64_fetch_and_relaxed atomic64_fetch_and_relaxed
188# define atomic64_fetch_or_relaxed atomic64_fetch_or_relaxed
189# define atomic64_fetch_xor_relaxed atomic64_fetch_xor_relaxed
190#endif
191
192#undef ATOMIC_OPS
193#undef ATOMIC_FETCH_OP
194#undef ATOMIC_OP_RETURN
195#undef ATOMIC_OP
196
197/*
198 * atomic_sub_if_positive - conditionally subtract integer from atomic variable
199 * @i: integer value to subtract
200 * @v: pointer of type atomic_t
201 *
202 * Atomically test @v and subtract @i if @v is greater or equal than @i.
203 * The function returns the old value of @v minus @i.
204 */
205#define ATOMIC_SIP_OP(pfx, type, op, ll, sc) \
206static __inline__ int pfx##_sub_if_positive(type i, pfx##_t * v) \
207{ \
208 type temp, result; \
209 \
210 smp_mb__before_atomic(); \
211 \
212 if (!kernel_uses_llsc) { \
213 unsigned long flags; \
214 \
215 raw_local_irq_save(flags); \
216 result = v->counter; \
217 result -= i; \
218 if (result >= 0) \
219 v->counter = result; \
220 raw_local_irq_restore(flags); \
221 smp_mb__after_atomic(); \
222 return result; \
223 } \
224 \
225 __asm__ __volatile__( \
226 " .set push \n" \
227 " .set " MIPS_ISA_LEVEL " \n" \
228 " " __SYNC(full, loongson3_war) " \n" \
229 "1: " #ll " %1, %2 # atomic_sub_if_positive\n" \
230 " .set pop \n" \
231 " " #op " %0, %1, %3 \n" \
232 " move %1, %0 \n" \
233 " bltz %0, 2f \n" \
234 " .set push \n" \
235 " .set " MIPS_ISA_LEVEL " \n" \
236 " " #sc " %1, %2 \n" \
237 " " __SC_BEQZ "%1, 1b \n" \
238 "2: " __SYNC(full, loongson3_war) " \n" \
239 " .set pop \n" \
240 : "=&r" (result), "=&r" (temp), \
241 "+" GCC_OFF_SMALL_ASM() (v->counter) \
242 : "Ir" (i) \
243 : __LLSC_CLOBBER); \
244 \
245 /* \
246 * In the Loongson3 workaround case we already have a \
247 * completion barrier at 2: above, which is needed due to the \
248 * bltz that can branch to code outside of the LL/SC loop. As \
249 * such, we don't need to emit another barrier here. \
250 */ \
251 if (!__SYNC_loongson3_war) \
252 smp_mb__after_atomic(); \
253 \
254 return result; \
255}
256
257ATOMIC_SIP_OP(atomic, int, subu, ll, sc)
258#define atomic_dec_if_positive(v) atomic_sub_if_positive(1, v)
259
260#ifdef CONFIG_64BIT
261ATOMIC_SIP_OP(atomic64, s64, dsubu, lld, scd)
262#define atomic64_dec_if_positive(v) atomic64_sub_if_positive(1, v)
263#endif
264
265#undef ATOMIC_SIP_OP
266
267#endif /* _ASM_ATOMIC_H */