From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sinan Kaya Subject: [PATCH v2 1/2] parisc: define stronger ordering for the default writeX() Date: Tue, 17 Apr 2018 00:08:50 -0400 Message-ID: <1523938133-3224-1-git-send-email-okaya@codeaurora.org> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-parisc@vger.kernel.org, arnd@arndb.de, timur@codeaurora.org, sulrich@codeaurora.org Cc: linux-arm-msm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Sinan Kaya , "James E.J. Bottomley" , Helge Deller , Thomas Gleixner , Greg Kroah-Hartman , Philippe Ombredanne , linux-kernel@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org parisc architecture seems to be mapping writeX() and writeX_relaxed() APIs to __raw_writeX() API. __raw_writeX() API doesn't provide any kind of ordering guarantees. commit 755bd04aaf4b ("io: define stronger ordering for the default writeX() implementation") changed asm-generic implementation to use a more conservative approach towards the writeX() API. Place a barrier() before the register write so that compiler doesn't optimize across the regiter operation. Signed-off-by: Sinan Kaya --- arch/parisc/include/asm/io.h | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/parisc/include/asm/io.h b/arch/parisc/include/asm/io.h index afe493b..2ec6405 100644 --- a/arch/parisc/include/asm/io.h +++ b/arch/parisc/include/asm/io.h @@ -196,18 +196,22 @@ static inline unsigned long long readq(const volatile void __iomem *addr) static inline void writeb(unsigned char b, volatile void __iomem *addr) { + barrier(); __raw_writeb(b, addr); } static inline void writew(unsigned short w, volatile void __iomem *addr) { + barrier(); __raw_writew((__u16 __force) cpu_to_le16(w), addr); } static inline void writel(unsigned int l, volatile void __iomem *addr) { + barrier(); __raw_writel((__u32 __force) cpu_to_le32(l), addr); } static inline void writeq(unsigned long long q, volatile void __iomem *addr) { + barrier(); __raw_writeq((__u64 __force) cpu_to_le64(q), addr); } -- 2.7.4