Current implementation uses following two methods
EnableNullDetection()
DisableNullDetection()
to enable/disable page 0. These two methods will check PCD
PcdNullPointerDetectionPropertyMask to know if the page 0 is disabled or not.
This is due to the fact that old GCD service doesn't provide paging related
attributes of memory block. Since this issue has been fixed, GCD services
can be used to determine the paging status of page 0. This is also make it
possible to just use a new macro
ACCESS_PAGE0_CODE(
<code accessing page 0>
);
to replace above methods to do the same job, which also makes code more
readability.
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>
Legacy has to access interrupt vector, BDA, etc. located in memory between
0-4095. To allow as much code as possible to be monitored by NULL pointer
detection, we add code to temporarily disable this feature right before
those memory access and enable it again afterwards.
Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Cc: Ayellet Wolman <ayellet.wolman@intel.com>
Suggested-by: Ayellet Wolman <ayellet.wolman@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>
Jian J Wang
jljusten