Add crypto target feature detection to arm32 (#833)

library/stdarch/crates/std_detect/src/detect/arch/arm.rs

@@ -16,4 +16,6 @@ features! {
     /// Polynomial Multiply
     @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] crc: "crc";
     /// CRC32 (Cyclic Redundancy Check)
+    @FEATURE: #[unstable(feature = "stdsimd", issue = "27731")] crypto: "crypto";
+    /// Crypto: AES + PMULL + SHA1 + SHA2
 }

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

@@ -20,6 +20,14 @@ pub(crate) fn detect_features() -> cache::Initializer {
         enable_feature(&mut value, Feature::neon, bit::test(auxv.hwcap, 12));
         enable_feature(&mut value, Feature::pmull, bit::test(auxv.hwcap2, 1));
         enable_feature(&mut value, Feature::crc, bit::test(auxv.hwcap2, 4));
+        enable_feature(
+            &mut value,
+            Feature::crypto,
+            bit::test(auxv.hwcap2, 0)
+                && bit::test(auxv.hwcap2, 1)
+                && bit::test(auxv.hwcap2, 2)
+                && bit::test(auxv.hwcap2, 3),
+        );
         return value;
     }
 
@@ -31,6 +39,14 @@ pub(crate) fn detect_features() -> cache::Initializer {
         );
         enable_feature(&mut value, Feature::pmull, c.field("Features").has("pmull"));
         enable_feature(&mut value, Feature::crc, c.field("Features").has("crc32"));
+        enable_feature(
+            &mut value,
+            Feature::crypto,
+            c.field("Features").has("aes")
+                && c.field("Features").has("pmull")
+                && c.field("Features").has("sha1")
+                && c.field("Features").has("sha2"),
+        );
         return value;
     }
     value

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

@@ -25,6 +25,7 @@ fn arm_linux() {
     println!("neon: {}", is_arm_feature_detected!("neon"));
     println!("pmull: {}", is_arm_feature_detected!("pmull"));
     println!("crc: {}", is_arm_feature_detected!("crc"));
+    println!("crypto: {}", is_arm_feature_detected!("crypto"));
 }
 
 #[test]