From mboxrd@z Thu Jan 1 00:00:00 1970 From: will.deacon@arm.com (Will Deacon) Date: Mon, 25 Mar 2013 18:19:41 +0000 Subject: [PATCH 4/4] ARM: atomics: don't use exclusives for atomic64 read/set with LPAE In-Reply-To: <1364235581-17900-1-git-send-email-will.deacon@arm.com> References: <1364235581-17900-1-git-send-email-will.deacon@arm.com> Message-ID: <1364235581-17900-5-git-send-email-will.deacon@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. Signed-off-by: Will Deacon --- arch/arm/include/asm/atomic.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) diff --git a/arch/arm/include/asm/atomic.h b/arch/arm/include/asm/atomic.h index c79f61f..da1c77d 100644 --- a/arch/arm/include/asm/atomic.h +++ b/arch/arm/include/asm/atomic.h @@ -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) { -- 1.8.0