xref: /openbmc/linux/arch/x86/include/asm/atomic64_64.h (revision 2c684d89)
1 #ifndef _ASM_X86_ATOMIC64_64_H
2 #define _ASM_X86_ATOMIC64_64_H
3 
4 #include <linux/types.h>
5 #include <asm/alternative.h>
6 #include <asm/cmpxchg.h>
7 
8 /* The 64-bit atomic type */
9 
10 #define ATOMIC64_INIT(i)	{ (i) }
11 
12 /**
13  * atomic64_read - read atomic64 variable
14  * @v: pointer of type atomic64_t
15  *
16  * Atomically reads the value of @v.
17  * Doesn't imply a read memory barrier.
18  */
19 static inline long atomic64_read(const atomic64_t *v)
20 {
21 	return READ_ONCE((v)->counter);
22 }
23 
24 /**
25  * atomic64_set - set atomic64 variable
26  * @v: pointer to type atomic64_t
27  * @i: required value
28  *
29  * Atomically sets the value of @v to @i.
30  */
31 static inline void atomic64_set(atomic64_t *v, long i)
32 {
33 	WRITE_ONCE(v->counter, i);
34 }
35 
36 /**
37  * atomic64_add - add integer to atomic64 variable
38  * @i: integer value to add
39  * @v: pointer to type atomic64_t
40  *
41  * Atomically adds @i to @v.
42  */
43 static __always_inline void atomic64_add(long i, atomic64_t *v)
44 {
45 	asm volatile(LOCK_PREFIX "addq %1,%0"
46 		     : "=m" (v->counter)
47 		     : "er" (i), "m" (v->counter));
48 }
49 
50 /**
51  * atomic64_sub - subtract the atomic64 variable
52  * @i: integer value to subtract
53  * @v: pointer to type atomic64_t
54  *
55  * Atomically subtracts @i from @v.
56  */
57 static inline void atomic64_sub(long i, atomic64_t *v)
58 {
59 	asm volatile(LOCK_PREFIX "subq %1,%0"
60 		     : "=m" (v->counter)
61 		     : "er" (i), "m" (v->counter));
62 }
63 
64 /**
65  * atomic64_sub_and_test - subtract value from variable and test result
66  * @i: integer value to subtract
67  * @v: pointer to type atomic64_t
68  *
69  * Atomically subtracts @i from @v and returns
70  * true if the result is zero, or false for all
71  * other cases.
72  */
73 static inline int atomic64_sub_and_test(long i, atomic64_t *v)
74 {
75 	GEN_BINARY_RMWcc(LOCK_PREFIX "subq", v->counter, "er", i, "%0", "e");
76 }
77 
78 /**
79  * atomic64_inc - increment atomic64 variable
80  * @v: pointer to type atomic64_t
81  *
82  * Atomically increments @v by 1.
83  */
84 static __always_inline void atomic64_inc(atomic64_t *v)
85 {
86 	asm volatile(LOCK_PREFIX "incq %0"
87 		     : "=m" (v->counter)
88 		     : "m" (v->counter));
89 }
90 
91 /**
92  * atomic64_dec - decrement atomic64 variable
93  * @v: pointer to type atomic64_t
94  *
95  * Atomically decrements @v by 1.
96  */
97 static __always_inline void atomic64_dec(atomic64_t *v)
98 {
99 	asm volatile(LOCK_PREFIX "decq %0"
100 		     : "=m" (v->counter)
101 		     : "m" (v->counter));
102 }
103 
104 /**
105  * atomic64_dec_and_test - decrement and test
106  * @v: pointer to type atomic64_t
107  *
108  * Atomically decrements @v by 1 and
109  * returns true if the result is 0, or false for all other
110  * cases.
111  */
112 static inline int atomic64_dec_and_test(atomic64_t *v)
113 {
114 	GEN_UNARY_RMWcc(LOCK_PREFIX "decq", v->counter, "%0", "e");
115 }
116 
117 /**
118  * atomic64_inc_and_test - increment and test
119  * @v: pointer to type atomic64_t
120  *
121  * Atomically increments @v by 1
122  * and returns true if the result is zero, or false for all
123  * other cases.
124  */
125 static inline int atomic64_inc_and_test(atomic64_t *v)
126 {
127 	GEN_UNARY_RMWcc(LOCK_PREFIX "incq", v->counter, "%0", "e");
128 }
129 
130 /**
131  * atomic64_add_negative - add and test if negative
132  * @i: integer value to add
133  * @v: pointer to type atomic64_t
134  *
135  * Atomically adds @i to @v and returns true
136  * if the result is negative, or false when
137  * result is greater than or equal to zero.
138  */
139 static inline int atomic64_add_negative(long i, atomic64_t *v)
140 {
141 	GEN_BINARY_RMWcc(LOCK_PREFIX "addq", v->counter, "er", i, "%0", "s");
142 }
143 
144 /**
145  * atomic64_add_return - add and return
146  * @i: integer value to add
147  * @v: pointer to type atomic64_t
148  *
149  * Atomically adds @i to @v and returns @i + @v
150  */
151 static __always_inline long atomic64_add_return(long i, atomic64_t *v)
152 {
153 	return i + xadd(&v->counter, i);
154 }
155 
156 static inline long atomic64_sub_return(long i, atomic64_t *v)
157 {
158 	return atomic64_add_return(-i, v);
159 }
160 
161 #define atomic64_inc_return(v)  (atomic64_add_return(1, (v)))
162 #define atomic64_dec_return(v)  (atomic64_sub_return(1, (v)))
163 
164 static inline long atomic64_cmpxchg(atomic64_t *v, long old, long new)
165 {
166 	return cmpxchg(&v->counter, old, new);
167 }
168 
169 static inline long atomic64_xchg(atomic64_t *v, long new)
170 {
171 	return xchg(&v->counter, new);
172 }
173 
174 /**
175  * atomic64_add_unless - add unless the number is a given value
176  * @v: pointer of type atomic64_t
177  * @a: the amount to add to v...
178  * @u: ...unless v is equal to u.
179  *
180  * Atomically adds @a to @v, so long as it was not @u.
181  * Returns the old value of @v.
182  */
183 static inline int atomic64_add_unless(atomic64_t *v, long a, long u)
184 {
185 	long c, old;
186 	c = atomic64_read(v);
187 	for (;;) {
188 		if (unlikely(c == (u)))
189 			break;
190 		old = atomic64_cmpxchg((v), c, c + (a));
191 		if (likely(old == c))
192 			break;
193 		c = old;
194 	}
195 	return c != (u);
196 }
197 
198 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
199 
200 /*
201  * atomic64_dec_if_positive - decrement by 1 if old value positive
202  * @v: pointer of type atomic_t
203  *
204  * The function returns the old value of *v minus 1, even if
205  * the atomic variable, v, was not decremented.
206  */
207 static inline long atomic64_dec_if_positive(atomic64_t *v)
208 {
209 	long c, old, dec;
210 	c = atomic64_read(v);
211 	for (;;) {
212 		dec = c - 1;
213 		if (unlikely(dec < 0))
214 			break;
215 		old = atomic64_cmpxchg((v), c, dec);
216 		if (likely(old == c))
217 			break;
218 		c = old;
219 	}
220 	return dec;
221 }
222 
223 #define ATOMIC64_OP(op)							\
224 static inline void atomic64_##op(long i, atomic64_t *v)			\
225 {									\
226 	asm volatile(LOCK_PREFIX #op"q %1,%0"				\
227 			: "+m" (v->counter)				\
228 			: "er" (i)					\
229 			: "memory");					\
230 }
231 
232 ATOMIC64_OP(and)
233 ATOMIC64_OP(or)
234 ATOMIC64_OP(xor)
235 
236 #undef ATOMIC64_OP
237 
238 #endif /* _ASM_X86_ATOMIC64_64_H */
239