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-rw-r--r--src/corelib/global/qrandom.cpp45
-rw-r--r--src/corelib/global/qrandom_p.h8
-rw-r--r--src/corelib/tools/qsimd.cpp68
-rw-r--r--src/corelib/tools/qsimd_p.h18
-rw-r--r--tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp6
5 files changed, 91 insertions, 54 deletions
diff --git a/src/corelib/global/qrandom.cpp b/src/corelib/global/qrandom.cpp
index fa26d54afa..b150a29b88 100644
--- a/src/corelib/global/qrandom.cpp
+++ b/src/corelib/global/qrandom.cpp
@@ -90,47 +90,6 @@ DECLSPEC_IMPORT BOOLEAN WINAPI SystemFunction036(PVOID RandomBuffer, ULONG Rando
QT_BEGIN_NAMESPACE
-#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
-static qsizetype qt_random_cpu(void *buffer, qsizetype count) Q_DECL_NOTHROW;
-
-# ifdef Q_PROCESSOR_X86_64
-# define _rdrandXX_step _rdrand64_step
-# else
-# define _rdrandXX_step _rdrand32_step
-# endif
-
-static QT_FUNCTION_TARGET(RDRND) qsizetype qt_random_cpu(void *buffer, qsizetype count) Q_DECL_NOTHROW
-{
- unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
- unsigned *end = ptr + count;
- int retries = 10;
-
- while (ptr + sizeof(qregisteruint)/sizeof(*ptr) <= end) {
- if (_rdrandXX_step(reinterpret_cast<qregisteruint *>(ptr)))
- ptr += sizeof(qregisteruint)/sizeof(*ptr);
- else if (--retries == 0)
- goto out;
- }
-
- while (sizeof(*ptr) != sizeof(qregisteruint) && ptr != end) {
- bool ok = _rdrand32_step(ptr);
- if (!ok && --retries)
- continue;
- if (ok)
- ++ptr;
- break;
- }
-
-out:
- return ptr - reinterpret_cast<unsigned *>(buffer);
-}
-#else
-static qsizetype qt_random_cpu(void *, qsizetype)
-{
- return 0;
-}
-#endif
-
enum {
// may be "overridden" by a member enum
FillBufferNoexcept = true
@@ -371,8 +330,8 @@ Q_NEVER_INLINE void QRandomGenerator::SystemGenerator::generate(quint32 *begin,
}
qsizetype filled = 0;
- if (qt_has_hwrng() && (uint(qt_randomdevice_control) & SkipHWRNG) == 0)
- filled += qt_random_cpu(buffer, count);
+ if (qHasHwrng() && (uint(qt_randomdevice_control) & SkipHWRNG) == 0)
+ filled += qRandomCpu(buffer, count);
if (filled != count && (uint(qt_randomdevice_control) & SkipSystemRNG) == 0) {
qsizetype bytesFilled =
diff --git a/src/corelib/global/qrandom_p.h b/src/corelib/global/qrandom_p.h
index 917a91098e..4a0adff51c 100644
--- a/src/corelib/global/qrandom_p.h
+++ b/src/corelib/global/qrandom_p.h
@@ -79,14 +79,6 @@ extern Q_CORE_EXPORT QBasicAtomicInteger<uint> qt_randomdevice_control;
enum { qt_randomdevice_control = 0 };
#endif
-inline bool qt_has_hwrng()
-{
-#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
- return qCpuHasFeature(RDRND);
-#else
- return false;
-#endif
-}
QT_END_NAMESPACE
diff --git a/src/corelib/tools/qsimd.cpp b/src/corelib/tools/qsimd.cpp
index ddd715f745..09c276c4e0 100644
--- a/src/corelib/tools/qsimd.cpp
+++ b/src/corelib/tools/qsimd.cpp
@@ -376,6 +376,38 @@ static quint64 detectProcessorFeatures()
features &= ~AllAVX512;
}
+#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
+ /**
+ * Some AMD CPUs (e.g. AMD A4-6250J and AMD Ryzen 3000-series) have a
+ * failing random generation instruction, which always returns
+ * 0xffffffff, even when generation was "successful".
+ *
+ * This code checks if hardware random generator generates four consecutive
+ * equal numbers. If it does, then we probably have a failing one and
+ * should disable it completely.
+ *
+ * https://bugreports.qt.io/browse/QTBUG-69423
+ */
+ if (features & CpuFeatureRDRND) {
+ const qsizetype testBufferSize = 4;
+ unsigned testBuffer[4] = {};
+
+ const qsizetype generated = qRandomCpu(testBuffer, testBufferSize);
+
+ if (Q_UNLIKELY(generated == testBufferSize &&
+ testBuffer[0] == testBuffer[1] &&
+ testBuffer[1] == testBuffer[2] &&
+ testBuffer[2] == testBuffer[3])) {
+
+ fprintf(stderr, "WARNING: CPU random generator seem to be failing, disable hardware random number generation\n");
+ fprintf(stderr, "WARNING: RDRND generated: 0x%x 0x%x 0x%x 0x%x\n",
+ testBuffer[0], testBuffer[1], testBuffer[2], testBuffer[3]);
+
+ features &= ~CpuFeatureRDRND;
+ }
+ }
+#endif
+
return features;
}
@@ -590,4 +622,40 @@ void qDumpCPUFeatures()
puts("");
}
+#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
+
+# ifdef Q_PROCESSOR_X86_64
+# define _rdrandXX_step _rdrand64_step
+# else
+# define _rdrandXX_step _rdrand32_step
+# endif
+
+QT_FUNCTION_TARGET(RDRND) qsizetype qRandomCpu(void *buffer, qsizetype count) Q_DECL_NOTHROW
+{
+ unsigned *ptr = reinterpret_cast<unsigned *>(buffer);
+ unsigned *end = ptr + count;
+ int retries = 10;
+
+ while (ptr + sizeof(qregisteruint)/sizeof(*ptr) <= end) {
+ if (_rdrandXX_step(reinterpret_cast<qregisteruint *>(ptr)))
+ ptr += sizeof(qregisteruint)/sizeof(*ptr);
+ else if (--retries == 0)
+ goto out;
+ }
+
+ while (sizeof(*ptr) != sizeof(qregisteruint) && ptr != end) {
+ bool ok = _rdrand32_step(ptr);
+ if (!ok && --retries)
+ continue;
+ if (ok)
+ ++ptr;
+ break;
+ }
+
+out:
+ return ptr - reinterpret_cast<unsigned *>(buffer);
+}
+#endif
+
+
QT_END_NAMESPACE
diff --git a/src/corelib/tools/qsimd_p.h b/src/corelib/tools/qsimd_p.h
index c36e1e484f..d603631a24 100644
--- a/src/corelib/tools/qsimd_p.h
+++ b/src/corelib/tools/qsimd_p.h
@@ -346,6 +346,15 @@ extern Q_CORE_EXPORT QBasicAtomicInteger<unsigned> qt_cpu_features[2];
#endif
Q_CORE_EXPORT quint64 qDetectCpuFeatures();
+#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
+Q_CORE_EXPORT qsizetype qRandomCpu(void *, qsizetype) Q_DECL_NOTHROW;
+#else
+static inline qsizetype qRandomCpu(void *, qsizetype) Q_DECL_NOTHROW
+{
+ return 0;
+}
+#endif
+
static inline quint64 qCpuFeatures()
{
quint64 features = qt_cpu_features[0].load();
@@ -362,6 +371,15 @@ static inline quint64 qCpuFeatures()
#define qCpuHasFeature(feature) (((qCompilerCpuFeatures & CpuFeature ## feature) == CpuFeature ## feature) \
|| ((qCpuFeatures() & CpuFeature ## feature) == CpuFeature ## feature))
+inline bool qHasHwrng()
+{
+#if defined(Q_PROCESSOR_X86) && QT_COMPILER_SUPPORTS_HERE(RDRND)
+ return qCpuHasFeature(RDRND);
+#else
+ return false;
+#endif
+}
+
#define ALIGNMENT_PROLOGUE_16BYTES(ptr, i, length) \
for (; i < static_cast<int>(qMin(static_cast<quintptr>(length), ((4 - ((reinterpret_cast<quintptr>(ptr) >> 2) & 0x3)) & 0x3))); ++i)
diff --git a/tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp b/tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp
index 7c04611823..dca49e9f7e 100644
--- a/tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp
+++ b/tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp
@@ -320,7 +320,7 @@ void tst_QRandomGenerator::generate32_data()
QTest::newRow("fixed") << (RandomValue32 & RandomDataMask);
QTest::newRow("global") << 0U;
#ifdef QT_BUILD_INTERNAL
- if (qt_has_hwrng())
+ if (qHasHwrng())
QTest::newRow("hwrng") << uint(UseSystemRNG);
QTest::newRow("system") << uint(UseSystemRNG | SkipHWRNG);
# ifdef HAVE_FALLBACK_ENGINE
@@ -755,7 +755,7 @@ void tst_QRandomGenerator::stdUniformIntDistribution_data()
auto newRow = [&](quint32 max) {
#ifdef QT_BUILD_INTERNAL
- if (qt_has_hwrng())
+ if (qHasHwrng())
QTest::addRow("hwrng:%u", max) << uint(UseSystemRNG) << max;
QTest::addRow("system:%u", max) << uint(UseSystemRNG | SkipHWRNG) << max;
# ifdef HAVE_FALLBACK_ENGINE
@@ -868,7 +868,7 @@ void tst_QRandomGenerator::stdUniformRealDistribution_data()
auto newRow = [&](double min, double sup) {
#ifdef QT_BUILD_INTERNAL
- if (qt_has_hwrng())
+ if (qHasHwrng())
QTest::addRow("hwrng:%g-%g", min, sup) << uint(UseSystemRNG) << min << sup;
QTest::addRow("system:%g-%g", min, sup) << uint(UseSystemRNG | SkipHWRNG) << min << sup;
# ifdef HAVE_FALLBACK_ENGINE
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-26 02:36:07 +0000