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Commit 4fd75911 authored by Will Deacon's avatar Will Deacon Committed by Russell King
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ARM: 7687/1: atomics: don't use exclusives for atomic64 read/set with LPAE 



To ease page table updates with 64-bit descriptors, CPUs implementing
LPAE are required to implement ldrd/strd as atomic operations.

This patch uses these accessors instead of the exclusive variants when
performing atomic64_{read,set} on LPAE systems.

Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 029baf14

arch/arm/include/asm/atomic.h

+24 −0
Original line number Diff line number Diff line
@@ -243,6 +243,29 @@ typedef struct { 


#define ATOMIC64_INIT(i) { (i) }



#ifdef CONFIG_ARM_LPAE

static inline u64 atomic64_read(const atomic64_t *v)

{

	u64 result;



	__asm__ __volatile__("@ atomic64_read\n"

"	ldrd	%0, %H0, [%1]"

	: "=&r" (result)

	: "r" (&v->counter), "Qo" (v->counter)

	);



	return result;

}



static inline void atomic64_set(atomic64_t *v, u64 i)

{

	__asm__ __volatile__("@ atomic64_set\n"

"	strd	%2, %H2, [%1]"

	: "=Qo" (v->counter)

	: "r" (&v->counter), "r" (i)

	);

}

#else

static inline u64 atomic64_read(const atomic64_t *v)

{

	u64 result;
@@ -269,6 +292,7 @@ static inline void atomic64_set(atomic64_t *v, u64 i) 
	: "r" (&v->counter), "r" (i)

	: "cc");

}

#endif



static inline void atomic64_add(u64 i, atomic64_t *v)

{