This is a note to let you know that I've just added the patch titled
MIPS: io: Add barrier after register read in readX()
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-add-barrier-after-register-read-in-readx.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: Thu, 12 Apr 2018 22:30:44 -0400
Subject: MIPS: io: Add barrier after register read in readX()
From: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
[ Upstream commit a1cc7034e33d12dc17d13fbcd7d597d552889097 ]
While a barrier is present in the writeX() functions before the register
write, a similar barrier is missing in the readX() functions after the
register read. This could allow memory accesses following readX() to
observe stale data.
Signed-off-by: Sinan Kaya <okaya@xxxxxxxxxxxxxx>
Reported-by: 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/19069/
[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, 2 insertions(+)
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -377,6 +377,8 @@ static inline type pfx##read##bwlq(const
BUG(); \
} \
\
+ /* prevent prefetching of coherent DMA data prematurely */ \
+ rmb(); \
return pfx##ioswab##bwlq(__mem, __val); \
}
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
