tree e1f877b5f3ba288aef17a0ffa59d013b3d84dde8
parent 41f38af02f7045c81fb5949dddb5db356b8a7b01
author Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com> 1439327386 -0700
committer ChromeOS Commit Bot <chromeos-commit-bot@chromium.org> 1439353524 +0000

braswell: allow dirty cache line evictions for SMRAM to stick

The BUNIT controls the policy for read/write access to physical
memory. For the SMRAM range the policy was not allowing dirty
evictions to the SMRAM when the core causing the eviction was not
in SMM mode. This could happen when the SMM handler dirtied a line
and then RSM'd back into non-SMM mode. The cache line was dirtied
while in SMM mode, but when that particular cache line was evicted
it would be silently dropped. Fix this by allowing the BUNIT to honor
writes to the SMRAM range while the evicting core is not in SMM mode.
The core SMRR msr provides the mechanism for disallowing general access
to the SMRAM region while it is not in SMM mode.

BUG=chrome-os-partner:43091
BRANCH=None
TEST=Run suspend_stress_test and ensure there is no hang SMI handler
on suspend-path.
Signed-off-by: Chiranjeevi Rapolu <chiranjeevi.rapolu@intel.com>

Change-Id: I3e7d41c794c6168eb2ad4eb047675bdb1728f72f
Reviewed-on: https://chromium-review.googlesource.com/292890
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Commit-Queue: Hannah Williams <hannah.williams@intel.com>
Tested-by: Hannah Williams <hannah.williams@intel.com>