| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| 2 | /****************************************************************************** |
| 3 | * |
| 4 | * Copyright © International Business Machines Corp., 2009 |
| 5 | * |
| 6 | * DESCRIPTION |
| 7 | * GCC atomic builtin wrappers |
| 8 | * http://gcc.gnu.org/onlinedocs/gcc-4.1.0/gcc/Atomic-Builtins.html |
| 9 | * |
| 10 | * AUTHOR |
| 11 | * Darren Hart <dvhart@linux.intel.com> |
| 12 | * |
| 13 | * HISTORY |
| 14 | * 2009-Nov-17: Initial version by Darren Hart <dvhart@linux.intel.com> |
| 15 | * |
| 16 | *****************************************************************************/ |
| 17 | |
| 18 | #ifndef _ATOMIC_H |
| 19 | #define _ATOMIC_H |
| 20 | |
| 21 | typedef struct { |
| 22 | volatile int val; |
| 23 | } atomic_t; |
| 24 | |
| 25 | #define ATOMIC_INITIALIZER { 0 } |
| 26 | |
| 27 | /** |
| 28 | * atomic_cmpxchg() - Atomic compare and exchange |
| 29 | * @uaddr: The address of the futex to be modified |
| 30 | * @oldval: The expected value of the futex |
| 31 | * @newval: The new value to try and assign the futex |
| 32 | * |
| 33 | * Return the old value of addr->val. |
| 34 | */ |
| 35 | static inline int |
| 36 | atomic_cmpxchg(atomic_t *addr, int oldval, int newval) |
| 37 | { |
| 38 | return __sync_val_compare_and_swap(&addr->val, oldval, newval); |
| 39 | } |
| 40 | |
| 41 | /** |
| 42 | * atomic_inc() - Atomic incrememnt |
| 43 | * @addr: Address of the variable to increment |
| 44 | * |
| 45 | * Return the new value of addr->val. |
| 46 | */ |
| 47 | static inline int |
| 48 | atomic_inc(atomic_t *addr) |
| 49 | { |
| 50 | return __sync_add_and_fetch(&addr->val, 1); |
| 51 | } |
| 52 | |
| 53 | /** |
| 54 | * atomic_dec() - Atomic decrement |
| 55 | * @addr: Address of the variable to decrement |
| 56 | * |
| 57 | * Return the new value of addr-val. |
| 58 | */ |
| 59 | static inline int |
| 60 | atomic_dec(atomic_t *addr) |
| 61 | { |
| 62 | return __sync_sub_and_fetch(&addr->val, 1); |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * atomic_set() - Atomic set |
| 67 | * @addr: Address of the variable to set |
| 68 | * @newval: New value for the atomic_t |
| 69 | * |
| 70 | * Return the new value of addr->val. |
| 71 | */ |
| 72 | static inline int |
| 73 | atomic_set(atomic_t *addr, int newval) |
| 74 | { |
| 75 | addr->val = newval; |
| 76 | return newval; |
| 77 | } |
| 78 | |
| 79 | #endif |