From d1646b37b1f0a04dc79a10438b82ed231786e871 Mon Sep 17 00:00:00 2001 From: Dmitry Kazakov Date: Thu, 5 Sep 2019 10:23:08 +0300 Subject: Fix QRandomGenerator initialization on AMD CPUs 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. Change-Id: I38c87920ca2e8cce4143afbff5e453ce3845d11a Fixes: QTBUG-69423 Reviewed-by: Edward Welbourne (cherry picked from commit 5839714d986f28412c9f9ed4801d1bf9378f7b51) Reviewed-by: Thiago Macieira --- tests/auto/corelib/global/qrandomgenerator/tst_qrandomgenerator.cpp | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'tests') 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 -- cgit v1.2.3