Reviewed-by: Ray Ni <ray...@intel.com> > -----Original Message----- > From: Wang, Jian J <jian.j.w...@intel.com> > Sent: Wednesday, November 6, 2019 9:14 PM > To: devel@edk2.groups.io > Cc: Bi, Dandan <dandan...@intel.com>; Gao, Liming <liming....@intel.com>; Ni, > Ray <ray...@intel.com>; Wu, Hao A > <hao.a...@intel.com>; Sean Brogan <sean.bro...@microsoft.com> > Subject: [PATCH 0/2] 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. > > Tests: > - run memtest86 with PcdNullPointerDetectionPropertyMask set to 0x03 > - run memtest86 with PcdNullPointerDetectionPropertyMask set to 0x83 > - boot OVMF into Windows 7 with PcdNullPointerDetectionPropertyMask set to > 0x83 > > Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1885 > Cc: Dandan Bi <dandan...@intel.com> > Cc: Liming Gao <liming....@intel.com> > Cc: Ray Ni <ray...@intel.com> > Cc: Hao A Wu <hao.a...@intel.com> > Cc: Sean Brogan <sean.bro...@microsoft.com> > > Jian J Wang (2): > MdeModulePkg/DxeIplPeim: reserve page 0 for NULL pointer detection > MdeModulePkg/Core/Dxe: free page 0 after disabling NULL pointer > detection > > MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 5 +++++ > MdeModulePkg/Core/DxeIplPeim/Ia32/DxeLoadFunc.c | 4 ++++ > MdeModulePkg/Core/DxeIplPeim/X64/DxeLoadFunc.c | 4 ++++ > 3 files changed, 13 insertions(+) > > -- > 2.17.1.windows.2
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