diff --git a/ceno_rt/ceno_link.x b/ceno_rt/ceno_link.x
index 956531d41..a12c3f226 100644
--- a/ceno_rt/ceno_link.x
+++ b/ceno_rt/ceno_link.x
@@ -1,4 +1,5 @@
 
+/* The address of this variable is the start of the stack (growing downwards). */
 _stack_start = ORIGIN(REGION_STACK) + LENGTH(REGION_STACK);
 _hints_start = ORIGIN(REGION_HINTS);
 _hints_length = LENGTH(REGION_HINTS);
diff --git a/ceno_rt/src/lib.rs b/ceno_rt/src/lib.rs
index c2ac022b9..1f25ea9a0 100644
--- a/ceno_rt/src/lib.rs
+++ b/ceno_rt/src/lib.rs
@@ -68,6 +68,7 @@ pub fn halt(exit_code: u32) -> ! {
     );
 }
 
+// Look in the linker scripts `ceno_link.x` and `memory.x` for symbols like `_stack_start`.
 #[cfg(target_arch = "riscv32")]
 global_asm!(
     "
@@ -98,8 +99,3 @@ _start:
     ecall
     ",
 );
-
-extern "C" {
-    // The address of this variable is the start of the stack (growing downwards).
-    static _stack_start: u8;
-}