forked from Minki/linux
62e8a3258b
This patch makes sure that atomic_{read,set}() are at least
{READ,WRITE}_ONCE().
We already had the 'requirement' that atomic_read() should use
ACCESS_ONCE(), and most archs had this, but a few were lacking.
All are now converted to use READ_ONCE().
And, by a symmetry and general paranoia argument, upgrade atomic_set()
to use WRITE_ONCE().
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: james.hogan@imgtec.com
Cc: linux-kernel@vger.kernel.org
Cc: oleg@redhat.com
Cc: will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
#ifndef __ARCH_H8300_ATOMIC__
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#define __ARCH_H8300_ATOMIC__
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#include <linux/types.h>
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#include <asm/cmpxchg.h>
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#define ATOMIC_INIT(i) { (i) }
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#define atomic_read(v) READ_ONCE((v)->counter)
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#define atomic_set(v, i) WRITE_ONCE(((v)->counter), (i))
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#include <linux/kernel.h>
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#define ATOMIC_OP_RETURN(op, c_op) \
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static inline int atomic_##op##_return(int i, atomic_t *v) \
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{ \
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h8300flags flags; \
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int ret; \
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\
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flags = arch_local_irq_save(); \
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ret = v->counter c_op i; \
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arch_local_irq_restore(flags); \
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return ret; \
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}
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#define ATOMIC_OP(op, c_op) \
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static inline void atomic_##op(int i, atomic_t *v) \
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{ \
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h8300flags flags; \
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\
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flags = arch_local_irq_save(); \
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v->counter c_op i; \
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arch_local_irq_restore(flags); \
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}
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ATOMIC_OP_RETURN(add, +=)
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ATOMIC_OP_RETURN(sub, -=)
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ATOMIC_OP(and, &=)
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ATOMIC_OP(or, |=)
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ATOMIC_OP(xor, ^=)
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#undef ATOMIC_OP_RETURN
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#undef ATOMIC_OP
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#define atomic_add(i, v) (void)atomic_add_return(i, v)
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#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
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#define atomic_sub(i, v) (void)atomic_sub_return(i, v)
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#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
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#define atomic_inc_return(v) atomic_add_return(1, v)
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#define atomic_dec_return(v) atomic_sub_return(1, v)
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#define atomic_inc(v) (void)atomic_inc_return(v)
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#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
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#define atomic_dec(v) (void)atomic_dec_return(v)
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#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
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static inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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int ret;
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h8300flags flags;
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flags = arch_local_irq_save();
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ret = v->counter;
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if (likely(ret == old))
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v->counter = new;
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arch_local_irq_restore(flags);
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return ret;
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}
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static inline int __atomic_add_unless(atomic_t *v, int a, int u)
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{
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int ret;
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h8300flags flags;
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flags = arch_local_irq_save();
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ret = v->counter;
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if (ret != u)
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v->counter += a;
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arch_local_irq_restore(flags);
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return ret;
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}
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#endif /* __ARCH_H8300_ATOMIC __ */
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