From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 3/6] ARM: prefetch: add support for prefetchw using pldw on SMP ARMv7+ CPUs
Date: Tue, 17 Sep 2013 14:29:35 +0100 [thread overview]
Message-ID: <1379424578-7477-4-git-send-email-will.deacon@arm.com> (raw)
In-Reply-To: <1379424578-7477-1-git-send-email-will.deacon@arm.com>
SMP ARMv7 CPUs implement the pldw instruction, which allows them to
prefetch data cachelines in an exclusive state.
This patch defines the prefetchw macro using pldw for CPUs that support
it.
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
arch/arm/include/asm/processor.h | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 26164c9..c3d5fc1 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -112,12 +112,19 @@ static inline void prefetch(const void *ptr)
:: "p" (ptr));
}
+#if __LINUX_ARM_ARCH__ >= 7 && defined(CONFIG_SMP)
#define ARCH_HAS_PREFETCHW
-#define prefetchw(ptr) prefetch(ptr)
-
-#define ARCH_HAS_SPINLOCK_PREFETCH
-#define spin_lock_prefetch(x) do { } while (0)
-
+static inline void prefetchw(const void *ptr)
+{
+ __asm__ __volatile__(
+ ".arch_extension mp\n"
+ __ALT_SMP_ASM(
+ WASM(pldw) "\t%a0",
+ WASM(pld) "\t%a0"
+ )
+ :: "p" (ptr));
+}
+#endif
#endif
#define HAVE_ARCH_PICK_MMAP_LAYOUT
--
1.8.2.2
next prev parent reply other threads:[~2013-09-17 13:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-17 13:29 [PATCH v3 0/6] Add support for pldw instruction on v7 MP cores Will Deacon
2013-09-17 13:29 ` [PATCH v3 1/6] ARM: prefetch: remove redundant "cc" clobber Will Deacon
2013-09-17 13:29 ` [PATCH v3 2/6] ARM: smp_on_up: move inline asm ALT_SMP patching macro out of spinlock.h Will Deacon
2013-09-17 13:29 ` Will Deacon [this message]
2013-09-17 13:29 ` [PATCH v3 4/6] ARM: locks: prefetch the destination word for write prior to strex Will Deacon
2013-09-17 13:29 ` [PATCH v3 5/6] ARM: atomics: " Will Deacon
2013-09-17 18:09 ` Nicolas Pitre
2013-09-18 9:54 ` Will Deacon
2013-09-17 13:29 ` [PATCH v3 6/6] ARM: bitops: " Will Deacon
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