diff --git a/libc/private/WriteProtected.h b/libc/private/WriteProtected.h
index d240e14..26c239c 100644
--- a/libc/private/WriteProtected.h
+++ b/libc/private/WriteProtected.h
@@ -47,11 +47,11 @@
   WriteProtectedContents<T> contents;
 
   int set_protection(int prot) {
-    auto addr = reinterpret_cast<uintptr_t>(&contents);
+    auto addr = &contents;
 #if __has_feature(hwaddress_sanitizer)
     // The mprotect system call does not currently untag pointers, so do it
     // ourselves.
-    addr &= (1ULL << 56) - 1;
+    addr = untag_address(addr);
 #endif
     return mprotect(reinterpret_cast<void*>(addr), PAGE_SIZE, prot);
   }
diff --git a/libc/private/bionic_macros.h b/libc/private/bionic_macros.h
index 4800e3a..13934e5 100644
--- a/libc/private/bionic_macros.h
+++ b/libc/private/bionic_macros.h
@@ -87,3 +87,12 @@
 #else
 #define __BIONIC_FALLTHROUGH
 #endif
+
+template <typename T>
+static inline T* untag_address(T* p) {
+#if defined(__aarch64__)
+  return reinterpret_cast<T*>(reinterpret_cast<uintptr_t>(p) & ((1ULL << 56) - 1));
+#else
+  return p;
+#endif
+}