diff --git a/libc/kernel/uapi/linux/rseq.h b/libc/kernel/uapi/linux/rseq.h
index 29a9457..ba0ceb1 100644
--- a/libc/kernel/uapi/linux/rseq.h
+++ b/libc/kernel/uapi/linux/rseq.h
@@ -47,7 +47,22 @@
 struct rseq {
   __u32 cpu_id_start;
   __u32 cpu_id;
-  __u64 rseq_cs;
+  union {
+    __u64 ptr64;
+#ifdef __LP64__
+    __u64 ptr;
+#else
+    struct {
+#if defined(__BYTE_ORDER) && __BYTE_ORDER == __BIG_ENDIAN || defined(__BIG_ENDIAN)
+      __u32 padding;
+      __u32 ptr32;
+#else
+      __u32 ptr32;
+      __u32 padding;
+#endif
+    } ptr;
+#endif
+  } rseq_cs;
   __u32 flags;
 } __attribute__((aligned(4 * sizeof(__u64))));
 #endif