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

Subject: [PATCH 0/2] New fix for icache coherency race
From: Lars Persson <>
Date: Thu, 26 Feb 2015 14:16:01 +0100
Cc:, Lars Persson <>
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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.

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(-)


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