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From: "Wu, Hao A" <hao.a.wu@intel.com>
To: "Dong, Eric" <eric.dong@intel.com>,
	"Zhang, Shenglei" <shenglei.zhang@intel.com>,
	"devel@edk2.groups.io" <devel@edk2.groups.io>
Cc: "Bi, Dandan" <dandan.bi@intel.com>,
	"Gao, Liming" <liming.gao@intel.com>,
	Laszlo Ersek <lersek@redhat.com>,
	"Dong, Eric" <eric.dong@intel.com>
Subject: Re: [PATCH 1/1] MdeModulePkg/DxeIplPeim: Relocate the operation of PageMapLevel5Entry++
Date: Tue, 13 Aug 2019 01:51:01 +0000	[thread overview]
Message-ID: <B80AF82E9BFB8E4FBD8C89DA810C6A093C918E35@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <20190812062444.14572-1-shenglei.zhang@intel.com>

Hello Eric,

Could you help to take a look at this one as well?


> -----Original Message-----
> From: Zhang, Shenglei
> Sent: Monday, August 12, 2019 2:25 PM
> To: devel@edk2.groups.io
> Cc: Bi, Dandan; Gao, Liming; Wu, Hao A; Laszlo Ersek; Dong, Eric
> Subject: [PATCH 1/1] MdeModulePkg/DxeIplPeim: Relocate the operation of
> PageMapLevel5Entry++
> 
> 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.bi@intel.com>
> Cc: Liming Gao <liming.gao@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> Cc: Eric Dong <eric.dong@intel.com>
> Signed-off-by: Shenglei Zhang <shenglei.zhang@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++;
>      }


I think the change is fine,
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>

Best Regards,
Hao Wu


> 
>      for ( IndexOfPml4Entries = 0
> --
> 2.18.0.windows.1


  parent reply	other threads:[~2019-08-13  1:51 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-12  6:24 [PATCH 1/1] MdeModulePkg/DxeIplPeim: Relocate the operation of PageMapLevel5Entry++ Zhang, Shenglei
2019-08-12 13:06 ` Laszlo Ersek
2019-08-13  1:51 ` Wu, Hao A [this message]
2019-08-13  2:04 ` Dandan Bi
2019-08-13  2:17   ` Dong, Eric
2019-08-13 12:26 ` [edk2-devel] " Laszlo Ersek
2019-08-14  0:06   ` Wu, Hao A
2019-08-14  1:05 ` Wu, Hao A

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