linux-mips
[Top] [All Lists]

[PATCH 0/2] New fix for icache coherency race

To: linux-mips@linux-mips.org, ralf@linux-mips.org, paul.burton@imgtec.com
Subject: [PATCH 0/2] New fix for icache coherency race
From: Lars Persson <lars.persson@axis.com>
Date: Thu, 26 Feb 2015 14:16:01 +0100
Cc: linux-kernel@vger.kernel.org, Lars Persson <larper@axis.com>
List-archive: <http://www.linux-mips.org/archives/linux-mips/>
List-help: <mailto:ecartis@linux-mips.org?Subject=help>
List-id: linux-mips <linux-mips.eddie.linux-mips.org>
List-owner: <mailto:ralf@linux-mips.org>
List-post: <mailto:linux-mips@linux-mips.org>
List-software: Ecartis version 1.0.0
List-subscribe: <mailto:ecartis@linux-mips.org?subject=subscribe%20linux-mips>
List-unsubscribe: <mailto:ecartis@linux-mips.org?subject=unsubscribe%20linux-mips>
Original-recipient: rfc822;linux-mips@linux-mips.org
Sender: linux-mips-bounce@linux-mips.org
This patch set proposes an improved fix for the race condition that
originally was fixed in commit 2a4a8b1e5d9d ("MIPS: Remove race window
in page fault handling").

I have used the flush_icache_page API that is marked as deprecated in
Documentation/cachetlb.txt. There are strong reasons to keep this API
because it is not possible to implement an efficient and race-free
lazy flushing using the other APIs.

You can refer to a discussion about the same issue in arch/arm where
they chose to implement the solution in set_pte_at. In arch/mips we
could not do this because we lack information about the executability
of the mapping in set_pte_at() and thus we would have to flush all
pages to be safe.

http://lists.infradead.org/pipermail/linux-arm-kernel/2010-November/030915.html

Lars Persson (2):
  Revert "MIPS: Remove race window in page fault handling"
  MIPS: Fix race condition in lazy cache flushing.

 arch/mips/include/asm/cacheflush.h |   35 ++++++++++++++++++++---------------
 arch/mips/include/asm/pgtable.h    |   10 ++++++----
 arch/mips/mm/cache.c               |   27 ++++++++-------------------
 3 files changed, 34 insertions(+), 38 deletions(-)

-- 
1.7.10.4


<Prev in Thread] Current Thread [Next in Thread>