From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Sinan Kaya , Arnd Bergmann , Ralf Baechle , Paul Burton , linux-mips@linux-mips.org, James Hogan , Sasha Levin Subject: [PATCH 4.16 006/279] MIPS: io: Prevent compiler reordering writeX() Date: Mon, 18 Jun 2018 10:09:51 +0200 Message-Id: <20180618080609.101669238@linuxfoundation.org> In-Reply-To: <20180618080608.851973560@linuxfoundation.org> References: <20180618080608.851973560@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 4.16-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sinan Kaya [ Upstream commit f6b7aeee8f167409195fbf1364d02988fecad1d0 ] writeX() has strong ordering semantics with respect to memory updates. In the absence of a write barrier or a compiler barrier, the compiler can reorder register and memory update instructions. This breaks the writeX() API. Signed-off-by: Sinan Kaya Cc: Arnd Bergmann Cc: Ralf Baechle Cc: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/18997/ [jhogan@kernel.org: Tidy commit message] Signed-off-by: James Hogan Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/mips/include/asm/io.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/mips/include/asm/io.h +++ b/arch/mips/include/asm/io.h @@ -307,7 +307,7 @@ static inline void iounmap(const volatil #if defined(CONFIG_CPU_CAVIUM_OCTEON) || defined(CONFIG_LOONGSON3_ENHANCEMENT) #define war_io_reorder_wmb() wmb() #else -#define war_io_reorder_wmb() do { } while (0) +#define war_io_reorder_wmb() barrier() #endif #define __BUILD_MEMORY_SINGLE(pfx, bwlq, type, irq) \