Hello Shenglei,
On 08/12/19 08:24, Shenglei Zhang wrote:
> PageMapLevel5Entry may be uninitialized in original code, which means
> uninitialized pointer will be modified at some circumstance.
> So relocate the operation of PageMapLevel5Entry++ in order to make sure
> the pointer could be modified only when it is uninitialized.
>
> Cc: Dandan Bi <dandan...@intel.com>
> Cc: Liming Gao <liming....@intel.com>
> Cc: Hao A Wu <hao.a...@intel.com>
> Cc: Laszlo Ersek <ler...@redhat.com>
> Cc: Eric Dong <eric.d...@intel.com>
> Signed-off-by: Shenglei Zhang <shenglei.zh...@intel.com>
> ---
> MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> index b40b7e0c9813..2389f3eb485b 100644
> --- a/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> +++ b/MdeModulePkg/Core/DxeIplPeim/X64/VirtualMemory.c
> @@ -764,7 +764,7 @@ CreateIdentityMappingPageTables (
>
> for ( IndexOfPml5Entries = 0
> ; IndexOfPml5Entries < NumberOfPml5EntriesNeeded
> - ; IndexOfPml5Entries++, PageMapLevel5Entry++) {
> + ; IndexOfPml5Entries++) {
> //
> // Each PML5 entry points to a page of PML4 entires.
> // So lets allocate space for them and fill them in in the
> IndexOfPml4Entries loop.
> @@ -780,6 +780,7 @@ CreateIdentityMappingPageTables (
> PageMapLevel5Entry->Uint64 = (UINT64) (UINTN) PageMapLevel4Entry |
> AddressEncMask;
> PageMapLevel5Entry->Bits.ReadWrite = 1;
> PageMapLevel5Entry->Bits.Present = 1;
> + PageMapLevel5Entry++;
> }
>
> for ( IndexOfPml4Entries = 0
>
I prefer to leave this to the other people on CC.
Thanks
Laszlo
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