diff --git a/libc/kernel/arch-x86/asm/prctl.h b/libc/kernel/arch-x86/asm/prctl.h
new file mode 100644
index 0000000..8852ca7
--- /dev/null
+++ b/libc/kernel/arch-x86/asm/prctl.h
@@ -0,0 +1,20 @@
+/****************************************************************************
+ ****************************************************************************
+ ***
+ ***   This header was automatically generated from a Linux kernel header
+ ***   of the same name, to make information necessary for userspace to
+ ***   call into the kernel available to libc.  It contains only constants,
+ ***   structures, and macros generated from the original header, and thus,
+ ***   contains no copyrightable information.
+ ***
+ ****************************************************************************
+ ****************************************************************************/
+#ifndef X86_64_PRCTL_H
+#define X86_64_PRCTL_H 1
+
+#define ARCH_SET_GS 0x1001
+#define ARCH_SET_FS 0x1002
+#define ARCH_GET_FS 0x1003
+#define ARCH_GET_GS 0x1004
+
+#endif