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author | Will Deacon <will.deacon@arm.com> | 2016-06-08 15:10:57 +0100 |
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committer | Amit Pundir <amit.pundir@linaro.org> | 2016-10-12 17:34:22 +0530 |
commit | c749e858e15c8409af272aa5d1bbd3fc6ce46439 (patch) | |
tree | 854e2704f11471a8b156dc9423b5d3d4e4f47f29 /samples/rpmsg | |
parent | feffbe70d5610268474c76f429fa9dc4e9696d70 (diff) |
UPSTREAM: arm64: spinlock: fix spin_unlock_wait for LSE atomics
Commit d86b8da04dfa ("arm64: spinlock: serialise spin_unlock_wait against
concurrent lockers") fixed spin_unlock_wait for LL/SC-based atomics under
the premise that the LSE atomics (in particular, the LDADDA instruction)
are indivisible.
Unfortunately, these instructions are only indivisible when used with the
-AL (full ordering) suffix and, consequently, the same issue can
theoretically be observed with LSE atomics, where a later (in program
order) load can be speculated before the write portion of the atomic
operation.
This patch fixes the issue by performing a CAS of the lock once we've
established that it's unlocked, in much the same way as the LL/SC code.
Fixes: d86b8da04dfa ("arm64: spinlock: serialise spin_unlock_wait against concurrent lockers")
Signed-off-by: Will Deacon <will.deacon@arm.com>
Bug: 30369029
Patchset: kaslr-arm64-4.4
(cherry picked from commit 3a5facd09da848193f5bcb0dea098a298bc1a29d)
Signed-off-by: Jeff Vander Stoep <jeffv@google.com>
Change-Id: Icedaa4c508784bf43d0b5787586480fd668ccc49
Diffstat (limited to 'samples/rpmsg')
0 files changed, 0 insertions, 0 deletions