tyler.durden
/
audk
mirror of https://github.com/acidanthera/audk.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

MdeModulePkg/DxeIplPeim: reserve page 0 for NULL pointer detection 

When a boot loader examines the memory map, it can see that location 0
is available memory. If it chooses to use that memory, and
PcdNullPointerDetectionPropertyMask is enabled, use of memory in page 0
will cause an exception. This does occur when running the memtest86
program.

Leaving page 0 available is for legacy support purpose. Since we have
deprecated the support of legacy, the solution is just reserving it so
that it cannot be allocated for other uses.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1885
Cc: Dandan Bi <dandan.bi@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
This commit is contained in:
Jian J Wang 2019-11-06 21:13:32 +00:00 committed by Jian J Wang
parent f55c76b301
commit f9d0e5daa0
2 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c
View File

@ -246,8 +246,12 @@ HandOffToDxeCore (
EFI_PEI_VECTOR_HANDOFF_INFO_PPI *VectorHandoffInfoPpi;
BOOLEAN BuildPageTablesIa32Pae;
//
// Clear page 0 and mark it as allocated if NULL pointer detection is enabled.
//
if (IsNullDetectionEnabled ()) {
ClearFirst4KPage (HobList.Raw);
BuildMemoryAllocationHob (0, EFI_PAGES_TO_SIZE (1), EfiBootServicesData);
}
Status = PeiServicesAllocatePages (EfiBootServicesData, EFI_SIZE_TO_PAGES (STACK_SIZE), &BaseOfStack);

4
MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c
View File

@ -36,8 +36,12 @@ HandOffToDxeCore (
EFI_VECTOR_HANDOFF_INFO *VectorInfo;
EFI_PEI_VECTOR_HANDOFF_INFO_PPI *VectorHandoffInfoPpi;
//
// Clear page 0 and mark it as allocated if NULL pointer detection is enabled.
//
if (IsNullDetectionEnabled ()) {
ClearFirst4KPage (HobList.Raw);
BuildMemoryAllocationHob (0, EFI_PAGES_TO_SIZE (1), EfiBootServicesData);
}
//