4.16-stable review patch. If anyone has any objections, please let me know.
------------------
From: Sinan Kaya okaya@codeaurora.org
[ 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@codeaurora.org Reported-by: 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/19069/ [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, 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); \ }