1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-or-later */
2*4882a593Smuzhiyun /******************************************************************************
3*4882a593Smuzhiyun *
4*4882a593Smuzhiyun * Copyright © International Business Machines Corp., 2009
5*4882a593Smuzhiyun *
6*4882a593Smuzhiyun * DESCRIPTION
7*4882a593Smuzhiyun * GCC atomic builtin wrappers
8*4882a593Smuzhiyun * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html
9*4882a593Smuzhiyun *
10*4882a593Smuzhiyun * AUTHOR
11*4882a593Smuzhiyun * Darren Hart <dvhart@linux.intel.com>
12*4882a593Smuzhiyun *
13*4882a593Smuzhiyun * HISTORY
14*4882a593Smuzhiyun * 2009-Nov-17: Initial version by Darren Hart <dvhart@linux.intel.com>
15*4882a593Smuzhiyun *
16*4882a593Smuzhiyun *****************************************************************************/
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun #ifndef _ATOMIC_H
19*4882a593Smuzhiyun #define _ATOMIC_H
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun typedef struct {
22*4882a593Smuzhiyun volatile int val;
23*4882a593Smuzhiyun } atomic_t;
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun #define ATOMIC_INITIALIZER { 0 }
26*4882a593Smuzhiyun
27*4882a593Smuzhiyun /**
28*4882a593Smuzhiyun * atomic_cmpxchg() - Atomic compare and exchange
29*4882a593Smuzhiyun * @uaddr: The address of the futex to be modified
30*4882a593Smuzhiyun * @oldval: The expected value of the futex
31*4882a593Smuzhiyun * @newval: The new value to try and assign the futex
32*4882a593Smuzhiyun *
33*4882a593Smuzhiyun * Return the old value of addr->val.
34*4882a593Smuzhiyun */
35*4882a593Smuzhiyun static inline int
atomic_cmpxchg(atomic_t * addr,int oldval,int newval)36*4882a593Smuzhiyun atomic_cmpxchg(atomic_t *addr, int oldval, int newval)
37*4882a593Smuzhiyun {
38*4882a593Smuzhiyun return __sync_val_compare_and_swap(&addr->val, oldval, newval);
39*4882a593Smuzhiyun }
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun /**
42*4882a593Smuzhiyun * atomic_inc() - Atomic incrememnt
43*4882a593Smuzhiyun * @addr: Address of the variable to increment
44*4882a593Smuzhiyun *
45*4882a593Smuzhiyun * Return the new value of addr->val.
46*4882a593Smuzhiyun */
47*4882a593Smuzhiyun static inline int
atomic_inc(atomic_t * addr)48*4882a593Smuzhiyun atomic_inc(atomic_t *addr)
49*4882a593Smuzhiyun {
50*4882a593Smuzhiyun return __sync_add_and_fetch(&addr->val, 1);
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
53*4882a593Smuzhiyun /**
54*4882a593Smuzhiyun * atomic_dec() - Atomic decrement
55*4882a593Smuzhiyun * @addr: Address of the variable to decrement
56*4882a593Smuzhiyun *
57*4882a593Smuzhiyun * Return the new value of addr-val.
58*4882a593Smuzhiyun */
59*4882a593Smuzhiyun static inline int
atomic_dec(atomic_t * addr)60*4882a593Smuzhiyun atomic_dec(atomic_t *addr)
61*4882a593Smuzhiyun {
62*4882a593Smuzhiyun return __sync_sub_and_fetch(&addr->val, 1);
63*4882a593Smuzhiyun }
64*4882a593Smuzhiyun
65*4882a593Smuzhiyun /**
66*4882a593Smuzhiyun * atomic_set() - Atomic set
67*4882a593Smuzhiyun * @addr: Address of the variable to set
68*4882a593Smuzhiyun * @newval: New value for the atomic_t
69*4882a593Smuzhiyun *
70*4882a593Smuzhiyun * Return the new value of addr->val.
71*4882a593Smuzhiyun */
72*4882a593Smuzhiyun static inline int
atomic_set(atomic_t * addr,int newval)73*4882a593Smuzhiyun atomic_set(atomic_t *addr, int newval)
74*4882a593Smuzhiyun {
75*4882a593Smuzhiyun addr->val = newval;
76*4882a593Smuzhiyun return newval;
77*4882a593Smuzhiyun }
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun #endif
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