[PATCH 16/18] x86: io: implement dummy relaxed accessor macros for writes

From: Will Deacon
Date: Thu Apr 17 2014 - 09:47:26 EST


write{b,w,l,q}_relaxed are implemented by some architectures in order to
permit memory-mapped I/O accesses with weaker barrier semantics than the
non-relaxed variants.

This patch adds dummy macros for the write accessors to x86, in the
same vein as the dummy definitions for the relaxed read accessors.

Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Signed-off-by: Will Deacon <will.deacon@xxxxxxx>
---
arch/x86/include/asm/io.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index b8237d8a1e0c..2ea07f5ec7b7 100644
--- a/arch/x86/include/asm/io.h
+++ b/arch/x86/include/asm/io.h
@@ -74,6 +74,9 @@ build_mmio_write(__writel, "l", unsigned int, "r", )
#define __raw_readw __readw
#define __raw_readl __readl

+#define writeb_relaxed(v, a) __writeb(v, a)
+#define writew_relaxed(v, a) __writew(v, a)
+#define writel_relaxed(v, a) __writel(v, a)
#define __raw_writeb __writeb
#define __raw_writew __writew
#define __raw_writel __writel
@@ -86,6 +89,7 @@ build_mmio_read(readq, "q", unsigned long, "=r", :"memory")
build_mmio_write(writeq, "q", unsigned long, "r", :"memory")

#define readq_relaxed(a) readq(a)
+#define writeq_relaxed(v, a) writeq(v, a)

#define __raw_readq(a) readq(a)
#define __raw_writeq(val, addr) writeq(val, addr)
--
1.9.1

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