1 /* SPDX-License-Identifier: GPL-2.0 */
2 /* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
3 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org>
4 */
5
6 #ifndef _ASM_PARISC_ATOMIC_H_
7 #define _ASM_PARISC_ATOMIC_H_
8
9 #include <linux/types.h>
10 #include <asm/cmpxchg.h>
11 #include <asm/barrier.h>
12
13 /*
14 * Atomic operations that C can't guarantee us. Useful for
15 * resource counting etc..
16 *
17 * And probably incredibly slow on parisc. OTOH, we don't
18 * have to write any serious assembly. prumpf
19 */
20
21 #ifdef CONFIG_SMP
22 #include <asm/spinlock.h>
23 #include <asm/cache.h> /* we use L1_CACHE_BYTES */
24
25 /* Use an array of spinlocks for our atomic_ts.
26 * Hash function to index into a different SPINLOCK.
27 * Since "a" is usually an address, use one spinlock per cacheline.
28 */
29 # define ATOMIC_HASH_SIZE 4
30 # define ATOMIC_HASH(a) (&(__atomic_hash[ (((unsigned long) (a))/L1_CACHE_BYTES) & (ATOMIC_HASH_SIZE-1) ]))
31
32 extern arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned;
33
34 /* Can't use raw_spin_lock_irq because of #include problems, so
35 * this is the substitute */
36 #define _atomic_spin_lock_irqsave(l,f) do { \
37 arch_spinlock_t *s = ATOMIC_HASH(l); \
38 local_irq_save(f); \
39 arch_spin_lock(s); \
40 } while(0)
41
42 #define _atomic_spin_unlock_irqrestore(l,f) do { \
43 arch_spinlock_t *s = ATOMIC_HASH(l); \
44 arch_spin_unlock(s); \
45 local_irq_restore(f); \
46 } while(0)
47
48
49 #else
50 # define _atomic_spin_lock_irqsave(l,f) do { local_irq_save(f); } while (0)
51 # define _atomic_spin_unlock_irqrestore(l,f) do { local_irq_restore(f); } while (0)
52 #endif
53
54 /*
55 * Note that we need not lock read accesses - aligned word writes/reads
56 * are atomic, so a reader never sees inconsistent values.
57 */
58
atomic_set(atomic_t * v,int i)59 static __inline__ void atomic_set(atomic_t *v, int i)
60 {
61 unsigned long flags;
62 _atomic_spin_lock_irqsave(v, flags);
63
64 v->counter = i;
65
66 _atomic_spin_unlock_irqrestore(v, flags);
67 }
68
69 #define atomic_set_release(v, i) atomic_set((v), (i))
70
atomic_read(const atomic_t * v)71 static __inline__ int atomic_read(const atomic_t *v)
72 {
73 return READ_ONCE((v)->counter);
74 }
75
76 /* exported interface */
77 #define atomic_cmpxchg(v, o, n) (cmpxchg(&((v)->counter), (o), (n)))
78 #define atomic_xchg(v, new) (xchg(&((v)->counter), new))
79
80 /**
81 * __atomic_add_unless - add unless the number is a given value
82 * @v: pointer of type atomic_t
83 * @a: the amount to add to v...
84 * @u: ...unless v is equal to u.
85 *
86 * Atomically adds @a to @v, so long as it was not @u.
87 * Returns the old value of @v.
88 */
__atomic_add_unless(atomic_t * v,int a,int u)89 static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u)
90 {
91 int c, old;
92 c = atomic_read(v);
93 for (;;) {
94 if (unlikely(c == (u)))
95 break;
96 old = atomic_cmpxchg((v), c, c + (a));
97 if (likely(old == c))
98 break;
99 c = old;
100 }
101 return c;
102 }
103
104 #define ATOMIC_OP(op, c_op) \
105 static __inline__ void atomic_##op(int i, atomic_t *v) \
106 { \
107 unsigned long flags; \
108 \
109 _atomic_spin_lock_irqsave(v, flags); \
110 v->counter c_op i; \
111 _atomic_spin_unlock_irqrestore(v, flags); \
112 } \
113
114 #define ATOMIC_OP_RETURN(op, c_op) \
115 static __inline__ int atomic_##op##_return(int i, atomic_t *v) \
116 { \
117 unsigned long flags; \
118 int ret; \
119 \
120 _atomic_spin_lock_irqsave(v, flags); \
121 ret = (v->counter c_op i); \
122 _atomic_spin_unlock_irqrestore(v, flags); \
123 \
124 return ret; \
125 }
126
127 #define ATOMIC_FETCH_OP(op, c_op) \
128 static __inline__ int atomic_fetch_##op(int i, atomic_t *v) \
129 { \
130 unsigned long flags; \
131 int ret; \
132 \
133 _atomic_spin_lock_irqsave(v, flags); \
134 ret = v->counter; \
135 v->counter c_op i; \
136 _atomic_spin_unlock_irqrestore(v, flags); \
137 \
138 return ret; \
139 }
140
141 #define ATOMIC_OPS(op, c_op) \
142 ATOMIC_OP(op, c_op) \
143 ATOMIC_OP_RETURN(op, c_op) \
144 ATOMIC_FETCH_OP(op, c_op)
145
146 ATOMIC_OPS(add, +=)
147 ATOMIC_OPS(sub, -=)
148
149 #undef ATOMIC_OPS
150 #define ATOMIC_OPS(op, c_op) \
151 ATOMIC_OP(op, c_op) \
152 ATOMIC_FETCH_OP(op, c_op)
153
154 ATOMIC_OPS(and, &=)
155 ATOMIC_OPS(or, |=)
156 ATOMIC_OPS(xor, ^=)
157
158 #undef ATOMIC_OPS
159 #undef ATOMIC_FETCH_OP
160 #undef ATOMIC_OP_RETURN
161 #undef ATOMIC_OP
162
163 #define atomic_inc(v) (atomic_add( 1,(v)))
164 #define atomic_dec(v) (atomic_add( -1,(v)))
165
166 #define atomic_inc_return(v) (atomic_add_return( 1,(v)))
167 #define atomic_dec_return(v) (atomic_add_return( -1,(v)))
168
169 #define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
170
171 /*
172 * atomic_inc_and_test - increment and test
173 * @v: pointer of type atomic_t
174 *
175 * Atomically increments @v by 1
176 * and returns true if the result is zero, or false for all
177 * other cases.
178 */
179 #define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
180
181 #define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
182
183 #define atomic_sub_and_test(i,v) (atomic_sub_return((i),(v)) == 0)
184
185 #define ATOMIC_INIT(i) { (i) }
186
187 #ifdef CONFIG_64BIT
188
189 #define ATOMIC64_INIT(i) { (i) }
190
191 #define ATOMIC64_OP(op, c_op) \
192 static __inline__ void atomic64_##op(s64 i, atomic64_t *v) \
193 { \
194 unsigned long flags; \
195 \
196 _atomic_spin_lock_irqsave(v, flags); \
197 v->counter c_op i; \
198 _atomic_spin_unlock_irqrestore(v, flags); \
199 } \
200
201 #define ATOMIC64_OP_RETURN(op, c_op) \
202 static __inline__ s64 atomic64_##op##_return(s64 i, atomic64_t *v) \
203 { \
204 unsigned long flags; \
205 s64 ret; \
206 \
207 _atomic_spin_lock_irqsave(v, flags); \
208 ret = (v->counter c_op i); \
209 _atomic_spin_unlock_irqrestore(v, flags); \
210 \
211 return ret; \
212 }
213
214 #define ATOMIC64_FETCH_OP(op, c_op) \
215 static __inline__ s64 atomic64_fetch_##op(s64 i, atomic64_t *v) \
216 { \
217 unsigned long flags; \
218 s64 ret; \
219 \
220 _atomic_spin_lock_irqsave(v, flags); \
221 ret = v->counter; \
222 v->counter c_op i; \
223 _atomic_spin_unlock_irqrestore(v, flags); \
224 \
225 return ret; \
226 }
227
228 #define ATOMIC64_OPS(op, c_op) \
229 ATOMIC64_OP(op, c_op) \
230 ATOMIC64_OP_RETURN(op, c_op) \
231 ATOMIC64_FETCH_OP(op, c_op)
232
233 ATOMIC64_OPS(add, +=)
234 ATOMIC64_OPS(sub, -=)
235
236 #undef ATOMIC64_OPS
237 #define ATOMIC64_OPS(op, c_op) \
238 ATOMIC64_OP(op, c_op) \
239 ATOMIC64_FETCH_OP(op, c_op)
240
241 ATOMIC64_OPS(and, &=)
242 ATOMIC64_OPS(or, |=)
243 ATOMIC64_OPS(xor, ^=)
244
245 #undef ATOMIC64_OPS
246 #undef ATOMIC64_FETCH_OP
247 #undef ATOMIC64_OP_RETURN
248 #undef ATOMIC64_OP
249
250 static __inline__ void
atomic64_set(atomic64_t * v,s64 i)251 atomic64_set(atomic64_t *v, s64 i)
252 {
253 unsigned long flags;
254 _atomic_spin_lock_irqsave(v, flags);
255
256 v->counter = i;
257
258 _atomic_spin_unlock_irqrestore(v, flags);
259 }
260
261 static __inline__ s64
atomic64_read(const atomic64_t * v)262 atomic64_read(const atomic64_t *v)
263 {
264 return ACCESS_ONCE((v)->counter);
265 }
266
267 #define atomic64_inc(v) (atomic64_add( 1,(v)))
268 #define atomic64_dec(v) (atomic64_add( -1,(v)))
269
270 #define atomic64_inc_return(v) (atomic64_add_return( 1,(v)))
271 #define atomic64_dec_return(v) (atomic64_add_return( -1,(v)))
272
273 #define atomic64_add_negative(a, v) (atomic64_add_return((a), (v)) < 0)
274
275 #define atomic64_inc_and_test(v) (atomic64_inc_return(v) == 0)
276 #define atomic64_dec_and_test(v) (atomic64_dec_return(v) == 0)
277 #define atomic64_sub_and_test(i,v) (atomic64_sub_return((i),(v)) == 0)
278
279 /* exported interface */
280 #define atomic64_cmpxchg(v, o, n) \
281 ((__typeof__((v)->counter))cmpxchg(&((v)->counter), (o), (n)))
282 #define atomic64_xchg(v, new) (xchg(&((v)->counter), new))
283
284 /**
285 * atomic64_add_unless - add unless the number is a given value
286 * @v: pointer of type atomic64_t
287 * @a: the amount to add to v...
288 * @u: ...unless v is equal to u.
289 *
290 * Atomically adds @a to @v, so long as it was not @u.
291 * Returns the old value of @v.
292 */
atomic64_add_unless(atomic64_t * v,long a,long u)293 static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
294 {
295 long c, old;
296 c = atomic64_read(v);
297 for (;;) {
298 if (unlikely(c == (u)))
299 break;
300 old = atomic64_cmpxchg((v), c, c + (a));
301 if (likely(old == c))
302 break;
303 c = old;
304 }
305 return c != (u);
306 }
307
308 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
309
310 /*
311 * atomic64_dec_if_positive - decrement by 1 if old value positive
312 * @v: pointer of type atomic_t
313 *
314 * The function returns the old value of *v minus 1, even if
315 * the atomic variable, v, was not decremented.
316 */
atomic64_dec_if_positive(atomic64_t * v)317 static inline long atomic64_dec_if_positive(atomic64_t *v)
318 {
319 long c, old, dec;
320 c = atomic64_read(v);
321 for (;;) {
322 dec = c - 1;
323 if (unlikely(dec < 0))
324 break;
325 old = atomic64_cmpxchg((v), c, dec);
326 if (likely(old == c))
327 break;
328 c = old;
329 }
330 return dec;
331 }
332
333 #endif /* !CONFIG_64BIT */
334
335
336 #endif /* _ASM_PARISC_ATOMIC_H_ */
337