This is a note to let you know that I've just added the patch titled
MIPS: io: Prevent compiler reordering writeX()
to the 4.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mips-io-prevent-compiler-reordering-writex.patch
and it can be found in the queue-4.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Sun Jun 17 12:07:33 CEST 2018
From: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
Date: Tue, 3 Apr 2018 08:55:03 -0400
Subject: MIPS: io: Prevent compiler reordering writeX()
From: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
[ 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@xxxxxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
Patchwork: https://patchwork.linux-mips.org/patch/18997/
[jhogan@xxxxxxxxxx: Tidy commit message]
Signed-off-by: James Hogan <jhogan@xxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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) \
Patches currently in stable-queue which might be from okaya@xxxxxxxxxxxxxx are
queue-4.16/mips-io-add-barrier-after-register-read-in-readx.patch
queue-4.16/mips-io-prevent-compiler-reordering-writex.patch
