From 8e4bff4cab0ddac6060645b0715210484d02ff40 Mon Sep 17 00:00:00 2001
From: Yuval Adam <_@yuv.al>
Date: Wed, 30 Aug 2017 08:25:59 +0000
Subject: Initial file dump from open source release

---
 arch/s390/kernel/mcount64.S | 65 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 arch/s390/kernel/mcount64.S

(limited to 'arch/s390/kernel/mcount64.S')

diff --git a/arch/s390/kernel/mcount64.S b/arch/s390/kernel/mcount64.S
new file mode 100644
index 00000000..1c52eae3
--- /dev/null
+++ b/arch/s390/kernel/mcount64.S
@@ -0,0 +1,65 @@
+/*
+ * Copyright IBM Corp. 2008, 2009
+ *
+ *   Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ *
+ */
+
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+#include <asm/ftrace.h>
+
+	.section .kprobes.text, "ax"
+
+ENTRY(ftrace_stub)
+	br	%r14
+
+ENTRY(_mcount)
+#ifdef CONFIG_DYNAMIC_FTRACE
+	br	%r14
+
+ENTRY(ftrace_caller)
+#endif
+	larl	%r1,function_trace_stop
+	icm	%r1,0xf,0(%r1)
+	bnzr	%r14
+	stmg	%r2,%r5,32(%r15)
+	stg	%r14,112(%r15)
+	lgr	%r1,%r15
+	aghi	%r15,-160
+	stg	%r1,__SF_BACKCHAIN(%r15)
+	lgr	%r2,%r14
+	lg	%r3,168(%r15)
+	aghi	%r2,-MCOUNT_INSN_SIZE
+	larl	%r14,ftrace_trace_function
+	lg	%r14,0(%r14)
+	basr	%r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	lg	%r2,168(%r15)
+	lg	%r3,272(%r15)
+ENTRY(ftrace_graph_caller)
+# The bras instruction gets runtime patched to call prepare_ftrace_return.
+# See ftrace_enable_ftrace_graph_caller. The patched instruction is:
+#	bras	%r14,prepare_ftrace_return
+	bras	%r14,0f
+0:	stg	%r2,168(%r15)
+#endif
+	aghi	%r15,160
+	lmg	%r2,%r5,32(%r15)
+	lg	%r14,112(%r15)
+	br	%r14
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+ENTRY(return_to_handler)
+	stmg	%r2,%r5,32(%r15)
+	lgr	%r1,%r15
+	aghi	%r15,-160
+	stg	%r1,__SF_BACKCHAIN(%r15)
+	brasl	%r14,ftrace_return_to_handler
+	aghi	%r15,160
+	lgr	%r14,%r2
+	lmg	%r2,%r5,32(%r15)
+	br	%r14
+
+#endif
-- 
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