From d0b4a876459643ceae9661cc306fae34b8828fcb Mon Sep 17 00:00:00 2001 From: Huacai Chen Date: Tue, 12 Jun 2018 17:54:42 +0800 Subject: [PATCH] MIPS: io: Add barrier after register read in inX() While a barrier is present in the outX() functions before the register write, a similar barrier is missing in the inX() functions after the register read. This could allow memory accesses following inX() to observe stale data. This patch is very similar to commit 85f1e31de1931896a ("MIPS: io: Add barrier after register read in readX()"). Because war_io_reorder_wmb() is both used by writeX() and outX(), if readX() need a barrier then so does inX(). Cc: stable@vger.kernel.org Signed-off-by: Huacai Chen Patchwork: https://patchwork.linux-mips.org/patch/19516/ Signed-off-by: Paul Burton Cc: James Hogan Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang Cc: Zhangjin Wu Cc: Huacai Chen --- arch/mips/include/asm/io.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/mips/include/asm/io.h b/arch/mips/include/asm/io.h index a7d0b836f2f7d..cea8ad864b3f6 100644 --- a/arch/mips/include/asm/io.h +++ b/arch/mips/include/asm/io.h @@ -414,6 +414,8 @@ static inline type pfx##in##bwlq##p(unsigned long port) \ __val = *__addr; \ slow; \ \ + /* prevent prefetching of coherent DMA data prematurely */ \ + rmb(); \ return pfx##ioswab##bwlq(__addr, __val); \ } -- 2.39.5