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qsimd: perform RDSEED sanity check in case if available

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Fixes: QTBUG-134538
Pick-to: 6.8 6.5
Change-Id: Iab51337b9b27ccf48a0e60c08cf14706112b6235
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
(cherry picked from commit 1b8d08532227866409088c6c45e215acfbf33cc7)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Mikhail Paulyshka 2025-03-11 00:35:40 +03:00 committed by Qt Cherry-pick Bot
parent f249a5182f
commit 1921783936
1 changed files with 10 additions and 5 deletions
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15
src/corelib/global/qsimd.cpp
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@ -260,7 +260,7 @@ static inline quint64 detectProcessorFeatures()
X86_BASELINE "," QT_FUNCTION_TARGET_STRING_RDRND
#endif
static bool checkRdrndWorks() noexcept;
static bool checkRdrndWorks(quint64) noexcept;
QT_FUNCTION_TARGET_BASELINE
static int maxBasicCpuidSupported()
@ -466,7 +466,7 @@ static quint64 detectProcessorFeatures()
features &= ~req.cpu_features;
}
if (features & CpuFeatureRDRND && !checkRdrndWorks())
if (features & CpuFeatureRDRND && !checkRdrndWorks(features))
features &= ~(CpuFeatureRDRND | CpuFeatureRDSEED);
return features;
@ -778,7 +778,7 @@ out:
}
QT_FUNCTION_TARGET(BASELINE_RDRND) Q_DECL_COLD_FUNCTION
static bool checkRdrndWorks() noexcept
static bool checkRdrndWorks(quint64 features) noexcept
{
/*
* Some AMD CPUs (e.g. AMD A4-6250J and AMD Ryzen 3000-series) have a
@ -800,7 +800,12 @@ static bool checkRdrndWorks() noexcept
if (_compilerCpuFeatures & CpuFeatureRDRND)
return true;
unsigned *end = qt_random_rdrnd(testBuffer, testBuffer + TestBufferSize);
unsigned *end;
if (features & CpuFeatureRDSEED)
end = qt_random_rdseed(testBuffer, testBuffer + TestBufferSize);
else
end = qt_random_rdrnd(testBuffer, testBuffer + TestBufferSize);
if (end < testBuffer + 3) {
// Random generation didn't produce enough data for us to make a
// determination whether it's working or not. Assume it isn't, but
@ -838,7 +843,7 @@ QT_FUNCTION_TARGET(RDRND) qsizetype qRandomCpu(void *buffer, qsizetype count) no
return ptr - reinterpret_cast<unsigned *>(buffer);
}
#elif defined(Q_PROCESSOR_X86) && !defined(Q_PROCESSOR_ARM)
static bool checkRdrndWorks() noexcept { return false; }
static bool checkRdrndWorks(quint64) noexcept { return false; }
#endif // Q_PROCESSOR_X86 && RDRND
#if QT_SUPPORTS_INIT_PRIORITY