diff --git a/libc/kernel/uapi/linux/prctl.h b/libc/kernel/uapi/linux/prctl.h
index c8118da..2890747 100644
--- a/libc/kernel/uapi/linux/prctl.h
+++ b/libc/kernel/uapi/linux/prctl.h
@@ -153,6 +153,13 @@
 #define PR_SET_TAGGED_ADDR_CTRL 55
 #define PR_GET_TAGGED_ADDR_CTRL 56
 #define PR_TAGGED_ADDR_ENABLE (1UL << 0)
+#define PR_MTE_TCF_SHIFT 1
+#define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT)
+#define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT)
+#define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT)
+#define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT)
+#define PR_MTE_TAG_SHIFT 3
+#define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT)
 #define PR_SET_IO_FLUSHER 57
 #define PR_GET_IO_FLUSHER 58
 #define PR_SET_VMA 0x53564d41