From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: [PATCH v2 16/18] x86: io: implement dummy relaxed accessor macros for writes Date: Thu, 22 May 2014 17:47:28 +0100 Message-ID: <1400777250-17335-17-git-send-email-will.deacon@arm.com> References: <1400777250-17335-1-git-send-email-will.deacon@arm.com> Return-path: Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:48927 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753113AbaEVQtK (ORCPT ); Thu, 22 May 2014 12:49:10 -0400 In-Reply-To: <1400777250-17335-1-git-send-email-will.deacon@arm.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Cc: arnd@arndb.de, monstr@monstr.eu, dhowells@redhat.com, broonie@linaro.org, benh@kernel.crashing.org, peterz@infradead.org, paulmck@linux.vnet.ibm.com, Will Deacon , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" 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 read and write accessors to x86, which simply expand to the non-relaxed variants. Note that this strengthens the relaxed read accessors, since they are now ordered with respect to each other by way of a compiler barrier. Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Signed-off-by: Will Deacon --- arch/x86/include/asm/io.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index b8237d8a1e0c..56d6d43aca9b 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -67,13 +67,16 @@ build_mmio_write(__writeb, "b", unsigned char, "q", ) build_mmio_write(__writew, "w", unsigned short, "r", ) build_mmio_write(__writel, "l", unsigned int, "r", ) -#define readb_relaxed(a) __readb(a) -#define readw_relaxed(a) __readw(a) -#define readl_relaxed(a) __readl(a) +#define readb_relaxed(a) readb(a) +#define readw_relaxed(a) readw(a) +#define readl_relaxed(a) readl(a) #define __raw_readb __readb #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) -- 1.9.2