Move `std_detect` from `library/stdarch` to `library`

1 files changed, 36 insertions, 0 deletions

diff --git a/library/std_detect/src/detect/os/freebsd/arm.rs b/library/std_detect/src/detect/os/freebsd/arm.rs
new file mode 100644
index 00000000000..0a15156e1bd
--- /dev/null
+++ b/library/std_detect/src/detect/os/freebsd/arm.rs
@@ -0,0 +1,36 @@
+//! Run-time feature detection for ARM on FreeBSD
+
+use super::auxvec;
+use crate::detect::{Feature, cache};
+
+// 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();
+    let enable_feature = |value: &mut cache::Initializer, f, enable| {
+        if enable {
+            value.set(f as u32);
+        }
+    };
+
+    if let Ok(auxv) = auxvec::auxv() {
+        enable_feature(&mut value, Feature::neon, auxv.hwcap & HWCAP_NEON != 0);
+        enable_feature(&mut value, Feature::pmull, auxv.hwcap2 & HWCAP2_PMULL != 0);
+        enable_feature(&mut value, Feature::crc, auxv.hwcap2 & HWCAP2_CRC32 != 0);
+        enable_feature(&mut value, Feature::aes, auxv.hwcap2 & HWCAP2_AES != 0);
+        // 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);
+        return value;
+    }
+    value
+}