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8fc4fddaf9
Implement generic support for local{,64}_try_cmpxchg().
Redirect to the atomic_ family of functions when the target
does not provide its own local.h definitions.
For 64-bit targets, implement local64_try_cmpxchg and
local64_cmpxchg using typed C wrappers that call local_
family of functions and provide additional checking
of their input arguments.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20230405141710.3551-3-ubizjak@gmail.com
Cc: Linus Torvalds <torvalds@linux-foundation.org>
107 lines
4 KiB
C
107 lines
4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_GENERIC_LOCAL64_H
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#define _ASM_GENERIC_LOCAL64_H
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#include <linux/percpu.h>
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#include <asm/types.h>
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/*
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* A signed long type for operations which are atomic for a single CPU.
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* Usually used in combination with per-cpu variables.
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*
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* This is the default implementation, which uses atomic64_t. Which is
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* rather pointless. The whole point behind local64_t is that some processors
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* can perform atomic adds and subtracts in a manner which is atomic wrt IRQs
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* running on this CPU. local64_t allows exploitation of such capabilities.
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*/
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/* Implement in terms of atomics. */
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#if BITS_PER_LONG == 64
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#include <asm/local.h>
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typedef struct {
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local_t a;
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} local64_t;
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#define LOCAL64_INIT(i) { LOCAL_INIT(i) }
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#define local64_read(l) local_read(&(l)->a)
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#define local64_set(l,i) local_set((&(l)->a),(i))
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#define local64_inc(l) local_inc(&(l)->a)
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#define local64_dec(l) local_dec(&(l)->a)
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#define local64_add(i,l) local_add((i),(&(l)->a))
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#define local64_sub(i,l) local_sub((i),(&(l)->a))
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#define local64_sub_and_test(i, l) local_sub_and_test((i), (&(l)->a))
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#define local64_dec_and_test(l) local_dec_and_test(&(l)->a)
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#define local64_inc_and_test(l) local_inc_and_test(&(l)->a)
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#define local64_add_negative(i, l) local_add_negative((i), (&(l)->a))
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#define local64_add_return(i, l) local_add_return((i), (&(l)->a))
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#define local64_sub_return(i, l) local_sub_return((i), (&(l)->a))
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#define local64_inc_return(l) local_inc_return(&(l)->a)
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static inline s64 local64_cmpxchg(local64_t *l, s64 old, s64 new)
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{
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return local_cmpxchg(&l->a, old, new);
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}
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static inline bool local64_try_cmpxchg(local64_t *l, s64 *old, s64 new)
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{
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return local_try_cmpxchg(&l->a, (long *)old, new);
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}
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#define local64_xchg(l, n) local_xchg((&(l)->a), (n))
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#define local64_add_unless(l, _a, u) local_add_unless((&(l)->a), (_a), (u))
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#define local64_inc_not_zero(l) local_inc_not_zero(&(l)->a)
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/* Non-atomic variants, ie. preemption disabled and won't be touched
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* in interrupt, etc. Some archs can optimize this case well. */
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#define __local64_inc(l) local64_set((l), local64_read(l) + 1)
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#define __local64_dec(l) local64_set((l), local64_read(l) - 1)
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#define __local64_add(i,l) local64_set((l), local64_read(l) + (i))
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#define __local64_sub(i,l) local64_set((l), local64_read(l) - (i))
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#else /* BITS_PER_LONG != 64 */
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#include <linux/atomic.h>
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/* Don't use typedef: don't want them to be mixed with atomic_t's. */
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typedef struct {
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atomic64_t a;
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} local64_t;
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#define LOCAL64_INIT(i) { ATOMIC_LONG_INIT(i) }
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#define local64_read(l) atomic64_read(&(l)->a)
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#define local64_set(l,i) atomic64_set((&(l)->a),(i))
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#define local64_inc(l) atomic64_inc(&(l)->a)
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#define local64_dec(l) atomic64_dec(&(l)->a)
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#define local64_add(i,l) atomic64_add((i),(&(l)->a))
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#define local64_sub(i,l) atomic64_sub((i),(&(l)->a))
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#define local64_sub_and_test(i, l) atomic64_sub_and_test((i), (&(l)->a))
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#define local64_dec_and_test(l) atomic64_dec_and_test(&(l)->a)
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#define local64_inc_and_test(l) atomic64_inc_and_test(&(l)->a)
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#define local64_add_negative(i, l) atomic64_add_negative((i), (&(l)->a))
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#define local64_add_return(i, l) atomic64_add_return((i), (&(l)->a))
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#define local64_sub_return(i, l) atomic64_sub_return((i), (&(l)->a))
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#define local64_inc_return(l) atomic64_inc_return(&(l)->a)
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#define local64_cmpxchg(l, o, n) atomic64_cmpxchg((&(l)->a), (o), (n))
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#define local64_try_cmpxchg(l, po, n) atomic64_try_cmpxchg((&(l)->a), (po), (n))
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#define local64_xchg(l, n) atomic64_xchg((&(l)->a), (n))
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#define local64_add_unless(l, _a, u) atomic64_add_unless((&(l)->a), (_a), (u))
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#define local64_inc_not_zero(l) atomic64_inc_not_zero(&(l)->a)
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/* Non-atomic variants, ie. preemption disabled and won't be touched
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* in interrupt, etc. Some archs can optimize this case well. */
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#define __local64_inc(l) local64_set((l), local64_read(l) + 1)
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#define __local64_dec(l) local64_set((l), local64_read(l) - 1)
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#define __local64_add(i,l) local64_set((l), local64_read(l) + (i))
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#define __local64_sub(i,l) local64_set((l), local64_read(l) - (i))
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#endif /* BITS_PER_LONG != 64 */
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#endif /* _ASM_GENERIC_LOCAL64_H */
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