2 files changed, 27 insertions, 0 deletions
diff --git a/library/std/src/sys/configure_builtins.rs b/library/std/src/sys/configure_builtins.rs
new file mode 100644
index 00000000000..9d776b778dc
--- /dev/null
+++ b/library/std/src/sys/configure_builtins.rs
@@ -0,0 +1,22 @@
+/// Hook into .init_array to enable LSE atomic operations at startup, if
+/// supported.
+#[cfg(all(target_arch = "aarch64", target_os = "linux", not(feature = "compiler-builtins-c")))]
+#[used]
+#[unsafe(link_section = ".init_array.90")]
+static RUST_LSE_INIT: extern "C" fn() = {
+    extern "C" fn init_lse() {
+        use crate::arch;
+
+        // This is provided by compiler-builtins::aarch64_linux.
+        unsafe extern "C" {
+            fn __rust_enable_lse();
+        }
+
+        if arch::is_aarch64_feature_detected!("lse") {
+            unsafe {
+                __rust_enable_lse();
+            }
+        }
+    }
+    init_lse
+};
diff --git a/library/std/src/sys/mod.rs b/library/std/src/sys/mod.rs
index f9a02b522e5..8ec0a0e3302 100644
--- a/library/std/src/sys/mod.rs
+++ b/library/std/src/sys/mod.rs
@@ -1,5 +1,10 @@
 #![allow(unsafe_op_in_unsafe_fn)]
 
+/// The configure builtins provides runtime support compiler-builtin features
+/// which require dynamic intialization to work as expected, e.g. aarch64
+/// outline-atomics.
+mod configure_builtins;
+
 /// The PAL (platform abstraction layer) contains platform-specific abstractions
 /// for implementing the features in the other submodules, e.g. UNIX file
 /// descriptors.