x86: io: implement dummy relaxed accessor macros for writes

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@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>

diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h
index b8237d8..2ea07f5 100644 (file)
--- 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)