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x86: Add disableAVX2/512 options and check XCR0 for OS support
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Signed-off-by: Bradley Wood <bradley.wood@ibm.com>
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BradleyWood committed Nov 7, 2024
1 parent be7ad36 commit 1e9014f
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Showing 2 changed files with 59 additions and 8 deletions.
34 changes: 30 additions & 4 deletions compiler/x/env/OMRCPU.cpp
Original file line number Diff line number Diff line change
Expand Up @@ -64,11 +64,37 @@ OMR::X86::CPU::detect(OMRPortLibrary * const omrPortLib)

if (TRUE == omrsysinfo_processor_has_feature(&processorDescription, OMR_FEATURE_X86_OSXSAVE))
{
static const bool disableAVX = feGetEnv("TR_DisableAVX") != NULL;
if (((6 & _xgetbv(0)) != 6) || disableAVX) // '6' = mask for XCR0[2:1]='11b' (XMM state and YMM state are enabled)
// Check XCRO register for OS support of xmm/ymm/zmm
// '6' = mask for XCR0[2:1]='11b' (XMM state and YMM state are enabled)
static const bool disableAVX = ((6 & _xgetbv(0)) != 6) || feGetEnv("TR_DisableAVX") != NULL;
static const bool disableAVX2 = disableAVX || feGetEnv("TR_DisableAVX2") != NULL;
// 'e0' = mask for XCR0[7:5]='111b' (Opmask, ZMM_Hi256, Hi16_ZMM)
static const bool disableAVX512 = ((0xe0 & _xgetbv(0)) != 0xe0) || disableAVX || disableAVX2 || feGetEnv("TR_DisableAVX512") != NULL;

if(disableAVX)
{
// Unset OSXSAVE if not enabled via CR0
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_OSXSAVE, FALSE);
// Unset AVX if not enabled via CR0 or otherwise disabled
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX, FALSE);
}

if (disableAVX2)
{
// Unset AVX if not enabled via CR0 or otherwise disabled
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX2, FALSE);
}

if (disableAVX512)
{
// Unset AVX-512 if not enabled via CR0 or otherwise disabled
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512F, FALSE);
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512VL, FALSE);
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512BW, FALSE);
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512DQ, FALSE);
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512CD, FALSE);

omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512_VBMI2, FALSE);
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512_BITALG, FALSE);
omrsysinfo_processor_set_feature(&processorDescription, OMR_FEATURE_X86_AVX512_VPOPCNTDQ, FALSE);
}
}

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33 changes: 29 additions & 4 deletions compiler/x/runtime/X86Runtime.hpp
Original file line number Diff line number Diff line change
Expand Up @@ -90,11 +90,36 @@ inline bool jitGetCPUID(TR_X86CPUIDBuffer* pBuffer)
// Check for XSAVE
if(pBuffer->_featureFlags2 & TR_OSXSAVE)
{
static const bool disableAVX = feGetEnv("TR_DisableAVX") != NULL;
if(((6 & _xgetbv(0)) != 6) || disableAVX) // '6' = mask for XCR0[2:1]='11b' (XMM state and YMM state are enabled)
// Check XCRO register for OS support of xmm/ymm/zmm
// '6' = mask for XCR0[2:1]='11b' (XMM state and YMM state are enabled)
static const bool disableAVX = ((6 & _xgetbv(0)) != 6) || feGetEnv("TR_DisableAVX") != NULL;
static const bool disableAVX2 = disableAVX || feGetEnv("TR_DisableAVX2") != NULL;
// 'e0' = mask for XCR0[7:5]='111b' (Opmask, ZMM_Hi256, Hi16_ZMM)
static const bool disableAVX512 = ((0xe6 & _xgetbv(0)) != 0xe6) || disableAVX || disableAVX2 || feGetEnv("TR_DisableAVX512") != NULL;

if(disableAVX)
{
pBuffer->_featureFlags2 &= ~TR_AVX; // Unset TR_AVX if not enabled via CR0 or otherwise disabled
}

if (disableAVX2)
{
// Unset OSXSAVE if not enabled via CR0
pBuffer->_featureFlags2 &= ~TR_OSXSAVE;
// Unset AVX2 if not enabled via CR0 or otherwise disabled
pBuffer->_featureFlags8 &= ~TR_AVX2;
}

if (disableAVX512)
{
// Unset AVX-512 if not enabled via CR0 or otherwise disabled
pBuffer->_featureFlags8 &= ~TR_AVX512F;
pBuffer->_featureFlags8 &= ~TR_AVX512VL;
pBuffer->_featureFlags8 &= ~TR_AVX512BW;
pBuffer->_featureFlags8 &= ~TR_AVX512DQ;
pBuffer->_featureFlags8 &= ~TR_AVX512CD;

pBuffer->_featureFlags10 &= ~TR_AVX512_VBMI2;
pBuffer->_featureFlags10 &= ~TR_AVX512_BITALG;
pBuffer->_featureFlags10 &= ~TR_AVX512_VPOPCNTDQ;
}
}

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