[PATCH v3 2/2] MIPS: io: add a barrier after register read in readX()

[Sinan Kaya]

While a barrier is present in writeX() function before the register write,
a similar barrier is missing in the readX() function after the register
read. This could allow memory accesses following readX() to observe
stale data.

Signed-off-by: Sinan Kaya <ok...@codeaurora.org>
Reported-by: Arnd Bergmann <a...@arndb.de>
---
 arch/mips/include/asm/io.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h
index fd00ddaf..6ac502f 100644
--- a/arch/mips/include/asm/io.h
+++ b/arch/mips/include/asm/io.h
@@ -377,6 +377,7 @@ static inline type pfx##read##bwlq(const volatile void 
__iomem *mem)        \
                BUG();                                                  \
        }                                                               \
                                                                        \
+       rmb();                                                          \
        return pfx##ioswab##bwlq(__mem, __val);                         \
 }
 
-- 
2.7.4