From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
To: "Gao, Liming" <liming.gao@intel.com>
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 08:51:20 +0000 [thread overview]
Message-ID: <CAKv+Gu9qjn=g-oFgifNSVFKgDBNopg-Vjggz5TE0D0iVNjHbSA@mail.gmail.com> (raw)
In-Reply-To: <4A89E2EF3DFEDB4C8BFDE51014F606A14E19885B@SHSMSX104.ccr.corp.intel.com>
On 26 December 2017 at 08:46, Gao, Liming <liming.gao@intel.com> wrote:
> 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);
>
That looks much better, thanks (although I prefer no space after the cast)
>>-----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
prev parent reply other threads:[~2017-12-26 8:46 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
2017-12-26 8:51 ` Ard Biesheuvel [this message]
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