From: "Gao, Liming" <liming.gao@intel.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: "edk2-devel@lists.01.org" <edk2-devel@lists.01.org>,
"Zeng, Star" <star.zeng@intel.com>
Subject: Re: [Patch] MdeModulePkg Variable: Update Pointer Minus with UINTN type
Date: Tue, 26 Dec 2017 08:46:50 +0000 [thread overview]
Message-ID: <4A89E2EF3DFEDB4C8BFDE51014F606A14E19885B@SHSMSX104.ccr.corp.intel.com> (raw)
In-Reply-To: <CAKv+Gu_+LOzijt-i7kTvQ-97n3feHo2Cu5Un1Dk9dErH5Lg3qA@mail.gmail.com>
Ard:
Here is the simpler version. Convert pointer to UINTN, then subtract them to get the size, last convert it to UINT32.
AuthVarStorage->Size = (UINT32)((UINTN) AuthStartPtr - (UINTN) AuthVarStorage);
Thanks
Liming
>-----Original Message-----
>From: Ard Biesheuvel [mailto:ard.biesheuvel@linaro.org]
>Sent: Tuesday, December 26, 2017 4:39 PM
>To: Gao, Liming <liming.gao@intel.com>
>Cc: edk2-devel@lists.01.org; Zeng, Star <star.zeng@intel.com>
>Subject: Re: [edk2] [Patch] MdeModulePkg Variable: Update Pointer Minus
>with UINTN type
>
>On 26 December 2017 at 08:36, Liming Gao <liming.gao@intel.com> wrote:
>> Contributed-under: TianoCore Contribution Agreement 1.1
>> Signed-off-by: Liming Gao <liming.gao@intel.com>
>> Cc: Star Zeng <star.zeng@intel.com>
>
>Could you please add an explanation why this is necessary? Do we
>really need 5 (!) casts to perform a simple subtraction?
>
>> ---
>> MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
>b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
>> index 77905a0..a47270a 100644
>> --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
>> +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
>> @@ -4125,7 +4125,7 @@ ConvertNormalVarStorageToAuthVarStorage (
>> //
>> AuthVarStorage->Format = NormalVarStorage->Format;
>> AuthVarStorage->State = NormalVarStorage->State;
>> - AuthVarStorage->Size = (UINT32) (UINTN) ((UINT8 *) AuthStartPtr -
>(UINT8 *) AuthVarStorage);
>> + AuthVarStorage->Size = (UINT32)((UINTN) (UINT8 *) AuthStartPtr -
>(UINTN) (UINT8 *) AuthVarStorage);
>> CopyGuid (&AuthVarStorage->Signature,
>&gEfiAuthenticatedVariableGuid);
>> ASSERT (AuthVarStorage->Size <= AuthVarStroageSize);
>>
>> --
>> 2.8.0.windows.1
>>
>> _______________________________________________
>> edk2-devel mailing list
>> edk2-devel@lists.01.org
>> https://lists.01.org/mailman/listinfo/edk2-devel
next prev parent reply other threads:[~2017-12-26 8:41 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-26 8:36 [Patch] MdeModulePkg Variable: Update Pointer Minus with UINTN type Liming Gao
2017-12-26 8:39 ` Ard Biesheuvel
2017-12-26 8:46 ` Gao, Liming [this message]
2017-12-26 8:51 ` Ard Biesheuvel
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