Reviewed-by: Liming Gao <liming....@intel.com> > -----Original Message----- > From: Kinney, Michael D <michael.d.kin...@intel.com> > Sent: Thursday, February 13, 2020 6:45 AM > To: devel@edk2.groups.io > Cc: Gao, Liming <liming....@intel.com>; Sean Brogan > <sean.bro...@microsoft.com>; Bret Barkelew <bret.barke...@microsoft.com> > Subject: [Patch] MdePkg/BaseSafeIntLib: Fix VS20xx IA32 link failures > > https://bugzilla.tianocore.org/show_bug.cgi?id=2525 > > SafeUint64Mult() looks for 64-bit overflows and performs > several 32-bit multiples with 64-bit results to check for > all possible overflow conditions. IA32 builds using VS20xx > with optimizations enabled are producing a reference to > the _allmull intrinsic. > > The fix is to use MultU64x64() instead of '*' for > these operations. These are safe because the inputs > are guaranteed to have the upper 32-bits clear, which > means MultU64x64() can never overflow with those inputs. > > Cc: Liming Gao <liming....@intel.com> > Cc: Sean Brogan <sean.bro...@microsoft.com> > Cc: Bret Barkelew <bret.barke...@microsoft.com> > Signed-off-by: Michael D Kinney <michael.d.kin...@intel.com> > --- > MdePkg/Library/BaseSafeIntLib/SafeIntLib.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/MdePkg/Library/BaseSafeIntLib/SafeIntLib.c > b/MdePkg/Library/BaseSafeIntLib/SafeIntLib.c > index 0f6be6e064..eec8ac1ffd 100644 > --- a/MdePkg/Library/BaseSafeIntLib/SafeIntLib.c > +++ b/MdePkg/Library/BaseSafeIntLib/SafeIntLib.c > @@ -3380,14 +3380,14 @@ SafeUint64Mult ( > // > // a * d must be less than 2^32 or there would be bits set in the high > 64-bits > // > - ProductAD = (((UINT64)DwordA) *(UINT64)DwordD); > + ProductAD = MultU64x64 ((UINT64)DwordA, (UINT64)DwordD); > if ((ProductAD & 0xffffffff00000000) == 0) { > DwordB = (UINT32)Multiplicand; > > // > // b * c must be less than 2^32 or there would be bits set in the > high 64-bits > // > - ProductBC = (((UINT64)DwordB) *(UINT64)DwordC); > + ProductBC = MultU64x64 ((UINT64)DwordB, (UINT64)DwordC); > if ((ProductBC & 0xffffffff00000000) == 0) { > // > // now sum them all up checking for overflow. > @@ -3397,7 +3397,7 @@ SafeUint64Mult ( > // > // b * d > // > - ProductBD = (((UINT64)DwordB) *(UINT64)DwordD); > + ProductBD = MultU64x64 ((UINT64)DwordB, (UINT64)DwordD); > > if (!RETURN_ERROR (SafeUint64Add (UnsignedResult, ProductBD, > &UnsignedResult))) { > *Result = UnsignedResult; > -- > 2.21.0.windows.1
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