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Clear Asan finding in VMAC under 32-bit inline ASM (GH #860) 

Second try. The first try cleared the Asan finding but broke at -O3. Eventually we will skin this cat.
pull/867/head
Jeffrey Walton 2019-07-05 16:33:01 -04:00
parent 7fd751ed36
commit ad99fc5b05
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GPG Key ID: B36AB348921B1838
1 changed files with 25 additions and 13 deletions
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38
vmac.cpp
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@ -178,11 +178,9 @@ unsigned int VMAC_Base::OptimalDataAlignment() const
#if CRYPTOPP_MSC_VERSION
# pragma warning(disable: 4731) // frame pointer register 'ebp' modified by inline assembly code
#endif
void
#ifdef __GNUC__
__attribute__ ((noinline)) // Intel Compiler 9.1 workaround
#endif
VMAC_Base::VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWord64, int tagPart)
CRYPTOPP_NOINLINE
void VMAC_Base::VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWord64, int tagPart)
{
const word64 *nhK = m_nhKey();
word64 *polyS = (word64*)(void*)m_polyState();
@ -193,13 +191,27 @@ VMAC_Base::VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWord64,
CRYPTOPP_UNUSED(L1KeyLength);
CRYPTOPP_UNUSED(blocksRemainingInWord64);
// This inline ASM is tricky, and down right difficult when PIC is
// in effect. The ASM uses all the general purpose registers. When
// PIC is in effect, GCC uses EBX as a base register. Saving EBX with
// 'mov %%ebx, %0' and restoring EBX with 'mov %0, %%ebx' causes GCC
// to generate 'mov -0x40(%ebx), %ebx' for the restore. That obviously
// won't work. We can push and pop EBX, but then we have to be careful
// because GCC references %1 (L1KeyLength) relative to ESP, which is
// also used in the function and no longer accurate. Attempting to
// sidestep the issues with clobber lists results in "error: ‘asm’
// operand has impossible constraints", though we were able to tell
// GCC that ESP is dirty. The problems with GCC are the reason for the
// pushes and pops rather than the original moves.
#ifdef __GNUC__
word32 temp;
// word32 temp;
__asm__ __volatile__
(
AS2( mov %%ebx, %0)
// AS1( push %%ebx)
AS2( mov %1, %%ebx)
// AS2( mov %%ebx, %0)
// AS2( mov %1, %%ebx) // L1KeyLength
AS1( push %%ebx)
AS1( push %0) // L1KeyLength
AS1( pop %%ebx)
INTEL_NOPREFIX
#else
#if defined(__INTEL_COMPILER)
@ -419,12 +431,12 @@ VMAC_Base::VHASH_Update_SSE2(const word64 *data, size_t blocksRemainingInWord64,
AS1( emms)
#ifdef __GNUC__
ATT_PREFIX
// AS1( pop %%ebx)
AS2( mov %0, %%ebx)
: "=m" (temp)
AS1( pop %%ebx)
// AS2( mov %0, %%ebx)
: // "=m" (temp)
: "m" (L1KeyLength), "c" (blocksRemainingInWord64), "S" (data),
"D" (nhK+tagPart*2), "d" (m_isFirstBlock), "a" (polyS+tagPart*4)
: "memory", "cc"
: "esp", "memory", "cc"
);
#endif
}