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From: Sinan Kaya <okaya@codeaurora.org>
To: linux-mips@linux-mips.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 <okaya@codeaurora.org>,
	Ralf Baechle <ralf@linux-mips.org>,
	James Hogan <jhogan@kernel.org>,
	Paul Burton <paul.burton@mips.com>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v3 1/2] MIPS: io: prevent compiler reordering on the default writeX() implementation
Date: Tue,  3 Apr 2018 08:55:03 -0400	[thread overview]
Message-ID: <1522760109-16497-1-git-send-email-okaya@codeaurora.org> (raw)

writeX() has a strong ordering semantics with respect to memory updates.
In the abscence of a write barrier or a compiler barrier, commpiler can
reorder register and memory update instructions. This breaks the writeX()
API.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 arch/mips/include/asm/io.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 0cbf3af..fd00ddaf 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -307,7 +307,7 @@ static inline void iounmap(const volatile void __iomem *addr)
 #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)			\
-- 
2.7.4

WARNING: multiple messages have this Message-ID (diff)
From: okaya@codeaurora.org (Sinan Kaya)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v3 1/2] MIPS: io: prevent compiler reordering on the default writeX() implementation
Date: Tue,  3 Apr 2018 08:55:03 -0400	[thread overview]
Message-ID: <1522760109-16497-1-git-send-email-okaya@codeaurora.org> (raw)

writeX() has a strong ordering semantics with respect to memory updates.
In the abscence of a write barrier or a compiler barrier, commpiler can
reorder register and memory update instructions. This breaks the writeX()
API.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
 arch/mips/include/asm/io.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index 0cbf3af..fd00ddaf 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -307,7 +307,7 @@ static inline void iounmap(const volatile void __iomem *addr)
 #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)			\
-- 
2.7.4

             reply	other threads:[~2018-04-03 12:55 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-03 12:55 Sinan Kaya [this message]
2018-04-03 12:55 ` [PATCH v3 1/2] MIPS: io: prevent compiler reordering on the default writeX() implementation Sinan Kaya
2018-04-03 12:55 ` [PATCH v3 2/2] MIPS: io: add a barrier after register read in readX() Sinan Kaya
2018-04-03 12:55   ` Sinan Kaya
2018-04-06  1:34   ` Sinan Kaya
2018-04-06  1:34     ` Sinan Kaya
2018-04-06 18:15     ` Sinan Kaya
2018-04-06 18:15       ` Sinan Kaya
2018-04-06 21:26       ` James Hogan
2018-04-06 21:26         ` James Hogan
2018-04-07 21:43         ` Sinan Kaya
2018-04-07 21:43           ` Sinan Kaya
2018-04-11 17:10           ` Sinan Kaya
2018-04-11 17:10             ` Sinan Kaya
2018-04-11 20:26             ` James Hogan
2018-04-11 20:26               ` James Hogan
2018-04-11 20:26               ` James Hogan
2018-04-11 20:26               ` James Hogan
2018-04-11 20:48               ` Sinan Kaya
2018-04-11 20:48                 ` Sinan Kaya
2018-04-11 17:04         ` Maciej W. Rozycki
2018-04-11 17:04           ` Maciej W. Rozycki
2018-04-11 17:04           ` Maciej W. Rozycki
2018-04-11 17:04           ` Maciej W. Rozycki
2018-04-12 21:51   ` James Hogan
2018-04-12 21:51     ` James Hogan
2018-04-12 21:51     ` James Hogan
2018-04-12 21:58     ` James Hogan
2018-04-12 21:58       ` James Hogan
2018-04-12 22:38       ` Sinan Kaya
2018-04-12 22:38         ` Sinan Kaya
2018-04-12 22:20     ` Sinan Kaya
2018-04-12 22:20       ` Sinan Kaya
2018-04-13 15:41     ` David Laight
2018-04-13 15:41       ` David Laight
2018-04-13 16:36       ` Sinan Kaya
2018-04-13 16:36         ` Sinan Kaya
2018-04-13 16:36         ` Sinan Kaya

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