From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "James Hogan" , "Fuxin Zhang" , "Huacai Chen" , "Huacai Chen" , linux-mips@linux-mips.org, "Paul Burton" , "Zhangjin Wu" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: Subject: [PATCH 3.16 156/366] MIPS: io: Add barrier after register read in inX() In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Huacai Chen commit 18f3e95b90b28318ef35910d21c39908de672331 upstream. 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 a1cc7034e33d12dc1 ("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(). 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 Signed-off-by: Ben Hutchings --- 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 @@ -410,6 +410,8 @@ static inline type pfx##in##bwlq##p(unsi __val = *__addr; \ slow; \ \ + /* prevent prefetching of coherent DMA data prematurely */ \ + rmb(); \ return pfx##ioswab##bwlq(__addr, __val); \ }