v4.19.13 snapshot.
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
new file mode 100644
index 0000000..8ea270f
--- /dev/null
+++ b/arch/s390/include/asm/ftrace.h
@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_FTRACE_H
+#define _ASM_S390_FTRACE_H
+
+#define ARCH_SUPPORTS_FTRACE_OPS 1
+
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
+#define MCOUNT_INSN_SIZE 6
+#else
+#define MCOUNT_INSN_SIZE 24
+#define MCOUNT_RETURN_FIXUP 18
+#endif
+
+#ifndef __ASSEMBLY__
+
+#define ftrace_return_address(n) __builtin_return_address(n)
+
+void _mcount(void);
+void ftrace_caller(void);
+
+extern char ftrace_graph_caller_end;
+extern unsigned long ftrace_plt;
+
+struct dyn_arch_ftrace { };
+
+#define MCOUNT_ADDR ((unsigned long)_mcount)
+#define FTRACE_ADDR ((unsigned long)ftrace_caller)
+
+#define KPROBE_ON_FTRACE_NOP 0
+#define KPROBE_ON_FTRACE_CALL 1
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ return addr;
+}
+
+struct ftrace_insn {
+ u16 opc;
+ s32 disp;
+} __packed;
+
+static inline void ftrace_generate_nop_insn(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
+ /* brcl 0,0 */
+ insn->opc = 0xc004;
+ insn->disp = 0;
+#else
+ /* jg .+24 */
+ insn->opc = 0xc0f4;
+ insn->disp = MCOUNT_INSN_SIZE / 2;
+#endif
+#endif
+}
+
+static inline int is_ftrace_nop(struct ftrace_insn *insn)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+#if defined(CC_USING_HOTPATCH) || defined(CC_USING_NOP_MCOUNT)
+ if (insn->disp == 0)
+ return 1;
+#else
+ if (insn->disp == MCOUNT_INSN_SIZE / 2)
+ return 1;
+#endif
+#endif
+ return 0;
+}
+
+static inline void ftrace_generate_call_insn(struct ftrace_insn *insn,
+ unsigned long ip)
+{
+#ifdef CONFIG_FUNCTION_TRACER
+ unsigned long target;
+
+ /* brasl r0,ftrace_caller */
+ target = is_module_addr((void *) ip) ? ftrace_plt : FTRACE_ADDR;
+ insn->opc = 0xc005;
+ insn->disp = (target - ip) / 2;
+#endif
+}
+
+#endif /* __ASSEMBLY__ */
+#endif /* _ASM_S390_FTRACE_H */