1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef __TOOLS_ASM_GENERIC_ATOMIC_H
3 #define __TOOLS_ASM_GENERIC_ATOMIC_H
5 #include <linux/compiler.h>
6 #include <linux/types.h>
7 #include <linux/bitops.h>
10 * Atomic operations that C can't guarantee us. Useful for
11 * resource counting etc..
13 * Excerpts obtained from the Linux kernel sources.
16 #define ATOMIC_INIT(i) { (i) }
19 * atomic_read - read atomic variable
20 * @v: pointer of type atomic_t
22 * Atomically reads the value of @v.
24 static inline int atomic_read(const atomic_t *v)
26 return READ_ONCE((v)->counter);
30 * atomic_set - set atomic variable
31 * @v: pointer of type atomic_t
34 * Atomically sets the value of @v to @i.
36 static inline void atomic_set(atomic_t *v, int i)
42 * atomic_inc - increment atomic variable
43 * @v: pointer of type atomic_t
45 * Atomically increments @v by 1.
47 static inline void atomic_inc(atomic_t *v)
49 __sync_add_and_fetch(&v->counter, 1);
53 * atomic_dec_and_test - decrement and test
54 * @v: pointer of type atomic_t
56 * Atomically decrements @v by 1 and
57 * returns true if the result is 0, or false for all other
60 static inline int atomic_dec_and_test(atomic_t *v)
62 return __sync_sub_and_fetch(&v->counter, 1) == 0;
65 #define cmpxchg(ptr, oldval, newval) \
66 __sync_val_compare_and_swap(ptr, oldval, newval)
68 static inline int atomic_cmpxchg(atomic_t *v, int oldval, int newval)
70 return cmpxchg(&(v)->counter, oldval, newval);
73 static inline int test_and_set_bit(long nr, unsigned long *addr)
75 unsigned long mask = BIT_MASK(nr);
80 old = __sync_fetch_and_or(addr, mask);
81 return !!(old & mask);
84 static inline int test_and_clear_bit(long nr, unsigned long *addr)
86 unsigned long mask = BIT_MASK(nr);
91 old = __sync_fetch_and_and(addr, ~mask);
92 return !!(old & mask);
95 #endif /* __TOOLS_ASM_GENERIC_ATOMIC_H */