1 files changed, 34 insertions, 0 deletions
diff --git a/library/std_detect/src/detect/os/linux/arm.rs b/library/std_detect/src/detect/os/linux/arm.rs
new file mode 100644
index 00000000000..bbb173227d0
--- /dev/null
+++ b/library/std_detect/src/detect/os/linux/arm.rs
@@ -0,0 +1,34 @@
+//! Run-time feature detection for ARM on Linux.
+
+use super::auxvec;
+use crate::detect::{Feature, bit, cache};
+
+/// Try to read the features from the auxiliary vector.
+pub(crate) fn detect_features() -> cache::Initializer {
+    let mut value = cache::Initializer::default();
+    let enable_feature = |value: &mut cache::Initializer, f, enable| {
+        if enable {
+            value.set(f as u32);
+        }
+    };
+
+    // The values are part of the platform-specific [asm/hwcap.h][hwcap]
+    //
+    // [hwcap]: https://github.com/torvalds/linux/blob/master/arch/arm/include/uapi/asm/hwcap.h
+    if let Ok(auxv) = auxvec::auxv() {
+        enable_feature(&mut value, Feature::i8mm, bit::test(auxv.hwcap, 27));
+        enable_feature(&mut value, Feature::dotprod, bit::test(auxv.hwcap, 24));
+        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::aes, bit::test(auxv.hwcap2, 0));
+        // SHA2 requires SHA1 & SHA2 features
+        enable_feature(
+            &mut value,
+            Feature::sha2,
+            bit::test(auxv.hwcap2, 2) && bit::test(auxv.hwcap2, 3),
+        );
+        return value;
+    }
+    value
+}