v4.19.13 snapshot.
diff --git a/arch/arm/include/asm/unwind.h b/arch/arm/include/asm/unwind.h
new file mode 100644
index 0000000..d1c3f3a
--- /dev/null
+++ b/arch/arm/include/asm/unwind.h
@@ -0,0 +1,61 @@
+/*
+ * arch/arm/include/asm/unwind.h
+ *
+ * Copyright (C) 2008 ARM Limited
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef __ASM_UNWIND_H
+#define __ASM_UNWIND_H
+
+#ifndef __ASSEMBLY__
+
+/* Unwind reason code according the the ARM EABI documents */
+enum unwind_reason_code {
+	URC_OK = 0,			/* operation completed successfully */
+	URC_CONTINUE_UNWIND = 8,
+	URC_FAILURE = 9			/* unspecified failure of some kind */
+};
+
+struct unwind_idx {
+	unsigned long addr_offset;
+	unsigned long insn;
+};
+
+struct unwind_table {
+	struct list_head list;
+	const struct unwind_idx *start;
+	const struct unwind_idx *origin;
+	const struct unwind_idx *stop;
+	unsigned long begin_addr;
+	unsigned long end_addr;
+};
+
+extern struct unwind_table *unwind_table_add(unsigned long start,
+					     unsigned long size,
+					     unsigned long text_addr,
+					     unsigned long text_size);
+extern void unwind_table_del(struct unwind_table *tab);
+extern void unwind_backtrace(struct pt_regs *regs, struct task_struct *tsk);
+
+#endif	/* !__ASSEMBLY__ */
+
+#ifdef CONFIG_ARM_UNWIND
+#define UNWIND(code...)		code
+#else
+#define UNWIND(code...)
+#endif
+
+#endif	/* __ASM_UNWIND_H */