v4.19.13 snapshot.
diff --git a/arch/x86/include/asm/kdebug.h b/arch/x86/include/asm/kdebug.h
new file mode 100644
index 0000000..75f1e35
--- /dev/null
+++ b/arch/x86/include/asm/kdebug.h
@@ -0,0 +1,43 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_KDEBUG_H
+#define _ASM_X86_KDEBUG_H
+
+#include <linux/notifier.h>
+
+struct pt_regs;
+
+/* Grossly misnamed. */
+enum die_val {
+	DIE_OOPS = 1,
+	DIE_INT3,
+	DIE_DEBUG,
+	DIE_PANIC,
+	DIE_NMI,
+	DIE_DIE,
+	DIE_KERNELDEBUG,
+	DIE_TRAP,
+	DIE_GPF,
+	DIE_CALL,
+	DIE_PAGE_FAULT,
+	DIE_NMIUNKNOWN,
+};
+
+enum show_regs_mode {
+	SHOW_REGS_SHORT,
+	/*
+	 * For when userspace crashed, but we don't think it's our fault, and
+	 * therefore don't print kernel registers.
+	 */
+	SHOW_REGS_USER,
+	SHOW_REGS_ALL
+};
+
+extern void die(const char *, struct pt_regs *,long);
+extern int __must_check __die(const char *, struct pt_regs *, long);
+extern void show_stack_regs(struct pt_regs *regs);
+extern void __show_regs(struct pt_regs *regs, enum show_regs_mode);
+extern void show_iret_regs(struct pt_regs *regs);
+extern unsigned long oops_begin(void);
+extern void oops_end(unsigned long, struct pt_regs *, int signr);
+
+#endif /* _ASM_X86_KDEBUG_H */