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:[email protected]] >Sent: Tuesday, December 26, 2017 4:39 PM >To: Gao, Liming <[email protected]> >Cc: [email protected]; Zeng, Star <[email protected]> >Subject: Re: [edk2] [Patch] MdeModulePkg Variable: Update Pointer Minus >with UINTN type > >On 26 December 2017 at 08:36, Liming Gao <[email protected]> wrote: >> Contributed-under: TianoCore Contribution Agreement 1.1 >> Signed-off-by: Liming Gao <[email protected]> >> Cc: Star Zeng <[email protected]> > >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 >> [email protected] >> https://lists.01.org/mailman/listinfo/edk2-devel _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
