1 #ifndef _ASM_GENERIC_LOCAL_H 2 #define _ASM_GENERIC_LOCAL_H 3 4 #include <linux/config.h> 5 #include <linux/percpu.h> 6 #include <linux/hardirq.h> 7 #include <asm/types.h> 8 9 /* An unsigned long type for operations which are atomic for a single 10 * CPU. Usually used in combination with per-cpu variables. */ 11 12 #if BITS_PER_LONG == 32 13 /* Implement in terms of atomics. */ 14 15 /* Don't use typedef: don't want them to be mixed with atomic_t's. */ 16 typedef struct 17 { 18 atomic_t a; 19 } local_t; 20 21 #define LOCAL_INIT(i) { ATOMIC_INIT(i) } 22 23 #define local_read(l) ((unsigned long)atomic_read(&(l)->a)) 24 #define local_set(l,i) atomic_set((&(l)->a),(i)) 25 #define local_inc(l) atomic_inc(&(l)->a) 26 #define local_dec(l) atomic_dec(&(l)->a) 27 #define local_add(i,l) atomic_add((i),(&(l)->a)) 28 #define local_sub(i,l) atomic_sub((i),(&(l)->a)) 29 30 /* Non-atomic variants, ie. preemption disabled and won't be touched 31 * in interrupt, etc. Some archs can optimize this case well. */ 32 #define __local_inc(l) local_set((l), local_read(l) + 1) 33 #define __local_dec(l) local_set((l), local_read(l) - 1) 34 #define __local_add(i,l) local_set((l), local_read(l) + (i)) 35 #define __local_sub(i,l) local_set((l), local_read(l) - (i)) 36 37 #else /* ... can't use atomics. */ 38 /* Implement in terms of three variables. 39 Another option would be to use local_irq_save/restore. */ 40 41 typedef struct 42 { 43 /* 0 = in hardirq, 1 = in softirq, 2 = usermode. */ 44 unsigned long v[3]; 45 } local_t; 46 47 #define _LOCAL_VAR(l) ((l)->v[!in_interrupt() + !in_irq()]) 48 49 #define LOCAL_INIT(i) { { (i), 0, 0 } } 50 51 static inline unsigned long local_read(local_t *l) 52 { 53 return l->v[0] + l->v[1] + l->v[2]; 54 } 55 56 static inline void local_set(local_t *l, unsigned long v) 57 { 58 l->v[0] = v; 59 l->v[1] = l->v[2] = 0; 60 } 61 62 static inline void local_inc(local_t *l) 63 { 64 preempt_disable(); 65 _LOCAL_VAR(l)++; 66 preempt_enable(); 67 } 68 69 static inline void local_dec(local_t *l) 70 { 71 preempt_disable(); 72 _LOCAL_VAR(l)--; 73 preempt_enable(); 74 } 75 76 static inline void local_add(unsigned long v, local_t *l) 77 { 78 preempt_disable(); 79 _LOCAL_VAR(l) += v; 80 preempt_enable(); 81 } 82 83 static inline void local_sub(unsigned long v, local_t *l) 84 { 85 preempt_disable(); 86 _LOCAL_VAR(l) -= v; 87 preempt_enable(); 88 } 89 90 /* Non-atomic variants, ie. preemption disabled and won't be touched 91 * in interrupt, etc. Some archs can optimize this case well. */ 92 #define __local_inc(l) ((l)->v[0]++) 93 #define __local_dec(l) ((l)->v[0]--) 94 #define __local_add(i,l) ((l)->v[0] += (i)) 95 #define __local_sub(i,l) ((l)->v[0] -= (i)) 96 97 #endif /* Non-atomic implementation */ 98 99 /* Use these for per-cpu local_t variables: on some archs they are 100 * much more efficient than these naive implementations. Note they take 101 * a variable (eg. mystruct.foo), not an address. 102 */ 103 #define cpu_local_read(v) local_read(&__get_cpu_var(v)) 104 #define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i)) 105 #define cpu_local_inc(v) local_inc(&__get_cpu_var(v)) 106 #define cpu_local_dec(v) local_dec(&__get_cpu_var(v)) 107 #define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v)) 108 #define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v)) 109 110 /* Non-atomic increments, ie. preemption disabled and won't be touched 111 * in interrupt, etc. Some archs can optimize this case well. 112 */ 113 #define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v)) 114 #define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v)) 115 #define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v)) 116 #define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v)) 117 118 #endif /* _ASM_GENERIC_LOCAL_H */ 119