1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _ASM_GENERIC_LOCAL_H 3 #define _ASM_GENERIC_LOCAL_H 4 5 #include <linux/percpu.h> 6 #include <linux/atomic.h> 7 #include <asm/types.h> 8 9 /* 10 * A signed long type for operations which are atomic for a single CPU. 11 * Usually used in combination with per-cpu variables. 12 * 13 * This is the default implementation, which uses atomic_long_t. Which is 14 * rather pointless. The whole point behind local_t is that some processors 15 * can perform atomic adds and subtracts in a manner which is atomic wrt IRQs 16 * running on this CPU. local_t allows exploitation of such capabilities. 17 */ 18 19 /* Implement in terms of atomics. */ 20 21 /* Don't use typedef: don't want them to be mixed with atomic_t's. */ 22 typedef struct 23 { 24 atomic_long_t a; 25 } local_t; 26 27 #define LOCAL_INIT(i) { ATOMIC_LONG_INIT(i) } 28 29 #define local_read(l) atomic_long_read(&(l)->a) 30 #define local_set(l,i) atomic_long_set((&(l)->a),(i)) 31 #define local_inc(l) atomic_long_inc(&(l)->a) 32 #define local_dec(l) atomic_long_dec(&(l)->a) 33 #define local_add(i,l) atomic_long_add((i),(&(l)->a)) 34 #define local_sub(i,l) atomic_long_sub((i),(&(l)->a)) 35 36 #define local_sub_and_test(i, l) atomic_long_sub_and_test((i), (&(l)->a)) 37 #define local_dec_and_test(l) atomic_long_dec_and_test(&(l)->a) 38 #define local_inc_and_test(l) atomic_long_inc_and_test(&(l)->a) 39 #define local_add_negative(i, l) atomic_long_add_negative((i), (&(l)->a)) 40 #define local_add_return(i, l) atomic_long_add_return((i), (&(l)->a)) 41 #define local_sub_return(i, l) atomic_long_sub_return((i), (&(l)->a)) 42 #define local_inc_return(l) atomic_long_inc_return(&(l)->a) 43 44 #define local_cmpxchg(l, o, n) atomic_long_cmpxchg((&(l)->a), (o), (n)) 45 #define local_try_cmpxchg(l, po, n) atomic_long_try_cmpxchg((&(l)->a), (po), (n)) 46 #define local_xchg(l, n) atomic_long_xchg((&(l)->a), (n)) 47 #define local_add_unless(l, _a, u) atomic_long_add_unless((&(l)->a), (_a), (u)) 48 #define local_inc_not_zero(l) atomic_long_inc_not_zero(&(l)->a) 49 50 /* Non-atomic variants, ie. preemption disabled and won't be touched 51 * in interrupt, etc. Some archs can optimize this case well. */ 52 #define __local_inc(l) local_set((l), local_read(l) + 1) 53 #define __local_dec(l) local_set((l), local_read(l) - 1) 54 #define __local_add(i,l) local_set((l), local_read(l) + (i)) 55 #define __local_sub(i,l) local_set((l), local_read(l) - (i)) 56 57 #endif /* _ASM_GENERIC_LOCAL_H */ 58