Add detection hwcap cpuid to hwcaps.h

BUILD.bazel

@@ -227,6 +227,7 @@ cc_library(
  ],
  PLATFORM_CPU_ARM: ["src/impl_arm_linux_or_android.c"],
  PLATFORM_CPU_ARM64: [
+ "src/impl_aarch64_cpuid.c",
  "src/impl_aarch64_linux_or_android.c",
  "src/impl_aarch64_macos_or_iphone.c",
  "src/impl_aarch64_windows.c",

include/internal/hwcaps.h

@@ -272,6 +272,10 @@ const char* CpuFeatures_GetPlatformPointer(void);
 // Get pointer for the AT_BASE_PLATFORM type.
 const char* CpuFeatures_GetBasePlatformPointer(void);
 
+// Checks whether privilege system registers are supported in user mode for
+// AArch64.
+bool CpuFeatures_IsHwCapCpuidSupported();
+
 CPU_FEATURES_END_CPP_NAMESPACE
 
 #endif // CPU_FEATURES_INCLUDE_INTERNAL_HWCAPS_H_

src/hwcaps_freebsd.c

@@ -14,7 +14,6 @@
 
 #include "cpu_features_macros.h"
 
-#ifdef CPU_FEATURES_ARCH_AARCH64
 #ifdef CPU_FEATURES_OS_FREEBSD
 
 #include "internal/hwcaps.h"
@@ -27,6 +26,7 @@ const char* CpuFeatures_GetBasePlatformPointer(void);
 #else
 
 #ifdef HAVE_STRONG_ELF_AUX_INFO
+#include <stdbool.h>
 #include <stddef.h>
 #include <sys/auxv.h>
 
@@ -46,10 +46,13 @@ HardwareCapabilities CpuFeatures_GetHardwareCapabilities(void) {
 const char *CpuFeatures_GetPlatformPointer(void) { return NULL; }
 
 const char *CpuFeatures_GetBasePlatformPointer(void) { return NULL; }
+
+bool CpuFeatures_IsHwCapCpuidSupported() {
+ return GetElfHwcapFromElfAuxInfo(AARCH64_HWCAP_CPUID);
+}
 #else
 #error "FreeBSD needs support for elf_aux_info"
 #endif // HAVE_STRONG_ELF_AUX_INFO
 
 #endif // CPU_FEATURES_TEST
 #endif // CPU_FEATURES_OS_FREEBSD
-#endif // CPU_FEATURES_ARCH_AARCH64

src/hwcaps_linux_or_android.c

@@ -153,5 +153,9 @@ const char *CpuFeatures_GetBasePlatformPointer(void) {
  return (const char *)GetHardwareCapabilitiesFor(AT_BASE_PLATFORM);
 }
 
+bool CpuFeatures_IsHwCapCpuidSupported() {
+ return GetElfHwcapFromGetauxval(AARCH64_HWCAP_CPUID);
+}
+
 #endif // CPU_FEATURES_TEST
 #endif // defined(CPU_FEATURES_OS_LINUX) || defined(CPU_FEATURES_OS_ANDROID)

src/impl_aarch64_cpuid.c

@@ -36,4 +36,4 @@ uint64_t GetMidrEl1() {
 #endif // (defined(CPU_FEATURES_COMPILER_GCC) ||
  // defined(CPU_FEATURES_COMPILER_CLANG))
 #endif // CPU_FEATURES_OS_FREEBSD
-#endif // CPU_FEATURES_ARCH_AARCH64
+#endif // CPU_FEATURES_ARCH_AARCH64

src/impl_aarch64_freebsd.c

@@ -12,17 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#include <printf.h>
-
 #include "cpu_features_macros.h"
 
 #ifdef CPU_FEATURES_ARCH_AARCH64
 #ifdef CPU_FEATURES_OS_FREEBSD
 
 #include "cpuinfo_aarch64.h"
-#include "internal/cpuid_aarch64.h"
 #include "impl_aarch64__base_implementation.inl"
-#include "sys/auxv.h"
+#include "internal/cpuid_aarch64.h"
+#include "internal/hwcaps.h"
 
 static const Aarch64Info kEmptyAarch64Info;
 
@@ -34,17 +32,13 @@ Aarch64Info GetAarch64Info(void) {
  kSetters[i](&info.features, true);
  }
  }
-
- unsigned long hwcap_cpuid;
- elf_aux_info(HWCAP_CPUID, &hwcap_cpuid, sizeof(hwcap_cpuid));
-
- if (hwcap_cpuid) {
- info.features.cpuid = true;
+ info.features.cpuid = CpuFeatures_IsHwCapCpuidSupported();
+ if (info.features.cpuid) {
  const uint64_t midr_el1 = GetMidrEl1();
- info.implementer = (int) ExtractBitRange(midr_el1, 31, 24);
- info.variant = (int) ExtractBitRange(midr_el1, 23, 20);
- info.part = (int) ExtractBitRange(midr_el1, 15, 4);
- info.revision = (int) ExtractBitRange(midr_el1, 3, 0);
+ info.implementer = (int)ExtractBitRange(midr_el1, 31, 24);
+ info.variant = (int)ExtractBitRange(midr_el1, 23, 20);
+ info.part = (int)ExtractBitRange(midr_el1, 15, 4);
+ info.revision = (int)ExtractBitRange(midr_el1, 3, 0);
  }
  return info;
 }