std_detect: Support run-time detection of crc/aes/sha2/crypto on arm FreeBSD

Author: taiki-e

library/stdarch/crates/std_detect/src/detect/os/freebsd/arm.rs

@@ -3,6 +3,15 @@
 use super::auxvec;
 use crate::detect::{cache, Feature};
 
+// Defined in machine/elf.h.
+// https://github.com/freebsd/freebsd-src/blob/deb63adf945d446ed91a9d84124c71f15ae571d1/sys/arm/include/elf.h
+const HWCAP_NEON: usize = 0x00001000;
+const HWCAP2_AES: usize = 0x00000001;
+const HWCAP2_PMULL: usize = 0x00000002;
+const HWCAP2_SHA1: usize = 0x00000004;
+const HWCAP2_SHA2: usize = 0x00000008;
+const HWCAP2_CRC32: usize = 0x00000010;
+
 /// Try to read the features from the auxiliary vector
 pub(crate) fn detect_features() -> cache::Initializer {
     let mut value = cache::Initializer::default();
@@ -13,8 +22,17 @@ pub(crate) fn detect_features() -> cache::Initializer {
     };
 
     if let Ok(auxv) = auxvec::auxv() {
-        enable_feature(&mut value, Feature::neon, auxv.hwcap & 0x00001000 != 0);
-        enable_feature(&mut value, Feature::pmull, auxv.hwcap2 & 0x00000002 != 0);
+        enable_feature(&mut value, Feature::neon, auxv.hwcap & HWCAP_NEON != 0);
+        let pmull = auxv.hwcap2 & HWCAP2_PMULL != 0;
+        enable_feature(&mut value, Feature::pmull, pmull);
+        enable_feature(&mut value, Feature::crc, auxv.hwcap2 & HWCAP2_CRC32 != 0);
+        let aes = auxv.hwcap2 & HWCAP2_AES != 0;
+        enable_feature(&mut value, Feature::aes, aes);
+        // SHA2 requires SHA1 & SHA2 features
+        let sha1 = auxv.hwcap2 & HWCAP2_SHA1 != 0;
+        let sha2 = auxv.hwcap2 & HWCAP2_SHA2 != 0;
+        enable_feature(&mut value, Feature::sha2, sha1 && sha2);
+        enable_feature(&mut value, Feature::crypto, aes && pmull && sha1 && sha2);
         return value;
     }
     value

library/stdarch/crates/std_detect/tests/cpu-detection.rs

@@ -20,8 +20,11 @@ fn all() {
 }
 
 #[test]
-#[cfg(all(target_arch = "arm", any(target_os = "linux", target_os = "android")))]
-fn arm_linux() {
+#[cfg(all(
+    target_arch = "arm",
+    any(target_os = "linux", target_os = "android", target_os = "freebsd"),
+))]
+fn arm_linux_or_freebsd() {
     println!("neon: {}", is_arm_feature_detected!("neon"));
     println!("pmull: {}", is_arm_feature_detected!("pmull"));
     println!("crc: {}", is_arm_feature_detected!("crc"));