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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 22:20:36 (GMT) |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /include/asm-generic/local.h | |
download | linux-fsl-qoriq-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'include/asm-generic/local.h')
-rw-r--r-- | include/asm-generic/local.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/include/asm-generic/local.h b/include/asm-generic/local.h new file mode 100644 index 0000000..16fc003 --- /dev/null +++ b/include/asm-generic/local.h @@ -0,0 +1,118 @@ +#ifndef _ASM_GENERIC_LOCAL_H +#define _ASM_GENERIC_LOCAL_H + +#include <linux/config.h> +#include <linux/percpu.h> +#include <linux/hardirq.h> +#include <asm/types.h> + +/* An unsigned long type for operations which are atomic for a single + * CPU. Usually used in combination with per-cpu variables. */ + +#if BITS_PER_LONG == 32 +/* Implement in terms of atomics. */ + +/* Don't use typedef: don't want them to be mixed with atomic_t's. */ +typedef struct +{ + atomic_t a; +} local_t; + +#define LOCAL_INIT(i) { ATOMIC_INIT(i) } + +#define local_read(l) ((unsigned long)atomic_read(&(l)->a)) +#define local_set(l,i) atomic_set((&(l)->a),(i)) +#define local_inc(l) atomic_inc(&(l)->a) +#define local_dec(l) atomic_dec(&(l)->a) +#define local_add(i,l) atomic_add((i),(&(l)->a)) +#define local_sub(i,l) atomic_sub((i),(&(l)->a)) + +/* Non-atomic variants, ie. preemption disabled and won't be touched + * in interrupt, etc. Some archs can optimize this case well. */ +#define __local_inc(l) local_set((l), local_read(l) + 1) +#define __local_dec(l) local_set((l), local_read(l) - 1) +#define __local_add(i,l) local_set((l), local_read(l) + (i)) +#define __local_sub(i,l) local_set((l), local_read(l) - (i)) + +#else /* ... can't use atomics. */ +/* Implement in terms of three variables. + Another option would be to use local_irq_save/restore. */ + +typedef struct +{ + /* 0 = in hardirq, 1 = in softirq, 2 = usermode. */ + unsigned long v[3]; +} local_t; + +#define _LOCAL_VAR(l) ((l)->v[!in_interrupt() + !in_irq()]) + +#define LOCAL_INIT(i) { { (i), 0, 0 } } + +static inline unsigned long local_read(local_t *l) +{ + return l->v[0] + l->v[1] + l->v[2]; +} + +static inline void local_set(local_t *l, unsigned long v) +{ + l->v[0] = v; + l->v[1] = l->v[2] = 0; +} + +static inline void local_inc(local_t *l) +{ + preempt_disable(); + _LOCAL_VAR(l)++; + preempt_enable(); +} + +static inline void local_dec(local_t *l) +{ + preempt_disable(); + _LOCAL_VAR(l)--; + preempt_enable(); +} + +static inline void local_add(unsigned long v, local_t *l) +{ + preempt_disable(); + _LOCAL_VAR(l) += v; + preempt_enable(); +} + +static inline void local_sub(unsigned long v, local_t *l) +{ + preempt_disable(); + _LOCAL_VAR(l) -= v; + preempt_enable(); +} + +/* Non-atomic variants, ie. preemption disabled and won't be touched + * in interrupt, etc. Some archs can optimize this case well. */ +#define __local_inc(l) ((l)->v[0]++) +#define __local_dec(l) ((l)->v[0]--) +#define __local_add(i,l) ((l)->v[0] += (i)) +#define __local_sub(i,l) ((l)->v[0] -= (i)) + +#endif /* Non-atomic implementation */ + +/* Use these for per-cpu local_t variables: on some archs they are + * much more efficient than these naive implementations. Note they take + * a variable (eg. mystruct.foo), not an address. + */ +#define cpu_local_read(v) local_read(&__get_cpu_var(v)) +#define cpu_local_set(v, i) local_set(&__get_cpu_var(v), (i)) +#define cpu_local_inc(v) local_inc(&__get_cpu_var(v)) +#define cpu_local_dec(v) local_dec(&__get_cpu_var(v)) +#define cpu_local_add(i, v) local_add((i), &__get_cpu_var(v)) +#define cpu_local_sub(i, v) local_sub((i), &__get_cpu_var(v)) + +/* Non-atomic increments, ie. preemption disabled and won't be touched + * in interrupt, etc. Some archs can optimize this case well. + */ +#define __cpu_local_inc(v) __local_inc(&__get_cpu_var(v)) +#define __cpu_local_dec(v) __local_dec(&__get_cpu_var(v)) +#define __cpu_local_add(i, v) __local_add((i), &__get_cpu_var(v)) +#define __cpu_local_sub(i, v) __local_sub((i), &__get_cpu_var(v)) + +#endif /* _ASM_GENERIC_LOCAL_H */ |