| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 005/189] MIPS: io: Prevent compiler reordering writeX() | Date | Mon, 18 Jun 2018 10:11:41 +0200 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Sinan Kaya <okaya@codeaurora.org>
[ 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 <okaya@codeaurora.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@mips.com> 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 <jhogan@kernel.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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) \
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