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Cleanup qsimd ARM code

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Switch to using getauxval.

Change-Id: I1a55cf24e3cacbbca1f57ad6f74a80df80fe60cf
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Allan Sandfeld Jensen 2021-04-20 12:19:53 +02:00
parent 8179d7edf6
commit ed82e1304d
1 changed files with 26 additions and 44 deletions
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70
src/corelib/global/qsimd.cpp
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@ -57,6 +57,10 @@
#elif defined(Q_OS_LINUX) && (defined(Q_PROCESSOR_ARM) || defined(Q_PROCESSOR_MIPS_32))
#include "private/qcore_unix_p.h"
#if QT_CONFIG(getauxval)
# include <sys/auxv.h>
#endif
// the kernel header definitions for HWCAP_*
// (the ones we need/may need anyway)
@ -134,54 +138,32 @@ static inline quint64 detectProcessorFeatures()
{
quint64 features = 0;
#if defined(Q_OS_LINUX)
# if defined(Q_PROCESSOR_ARM_V8) && defined(Q_PROCESSOR_ARM_64)
features |= CpuFeatureNEON; // NEON is always available on ARMv8 64bit.
#if QT_CONFIG(getauxval)
unsigned long auxvHwCap = getauxval(AT_HWCAP);
if (auxvHwCap != 0) {
# if defined(Q_PROCESSOR_ARM_64)
// For Aarch64:
features |= CpuFeatureNEON; // NEON is always available
if (auxvHwCap & HWCAP_CRC32)
features |= CpuFeatureCRC32;
if (auxvHwCap & HWCAP_AES)
features |= CpuFeatureAES;
# else
// For ARM32:
if (auxvHwCap & HWCAP_NEON)
features |= CpuFeatureNEON;
auxvHwCap = getauxval(AT_HWCAP2);
if (auxvHwCap & HWCAP2_CRC32)
features |= CpuFeatureCRC32;
if (auxvHwCap & HWCAP2_AES)
features |= CpuFeatureAES;
# endif
int auxv = qt_safe_open("/proc/self/auxv", O_RDONLY);
if (auxv != -1) {
unsigned long vector[64];
int nread;
while (features == 0) {
nread = qt_safe_read(auxv, (char *)vector, sizeof vector);
if (nread <= 0) {
// EOF or error
break;
}
int max = nread / (sizeof vector[0]);
for (int i = 0; i < max; i += 2) {
if (vector[i] == AT_HWCAP) {
# if defined(Q_PROCESSOR_ARM_V8) && defined(Q_PROCESSOR_ARM_64)
// For Aarch64:
if (vector[i+1] & HWCAP_CRC32)
features |= CpuFeatureCRC32;
if (vector[i+1] & HWCAP_AES)
features |= CpuFeatureAES;
# endif
// Aarch32, or ARMv7 or before:
if (vector[i+1] & HWCAP_NEON)
features |= CpuFeatureNEON;
}
# if defined(Q_PROCESSOR_ARM_32)
// For Aarch32:
if (vector[i] == AT_HWCAP2) {
if (vector[i+1] & HWCAP2_CRC32)
features |= CpuFeatureCRC32;
if (vector[i+1] & HWCAP2_AES)
features |= CpuFeatureAES;
}
# endif
}
}
qt_safe_close(auxv);
return features;
}
// fall back if /proc/self/auxv wasn't found
#endif
// fall back to compile-time flags if getauxval failed
#endif // QT_CONFIG(getauxval)
#if defined(__ARM_NEON__)
#if defined(__ARM_NEON__) || defined(__ARM_NEON)
features |= CpuFeatureNEON;
#endif
#if defined(__ARM_FEATURE_CRC32)