From 88dbd2037229bd2ed7543ffd0d8f2d9dec9d31d2 Mon Sep 17 00:00:00 2001
From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Fri, 12 Jun 2009 10:26:46 +0200
Subject: [S390] ftrace: add function graph tracer support

Function graph tracer support for s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
---
 arch/s390/kernel/mcount.S | 79 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

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

diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index 0aa85ec..2a0a5e9 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -34,6 +34,18 @@ ftrace_caller:
 	larl	%r14,ftrace_dyn_func
 	lg	%r14,0(%r14)
 	basr	%r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	.globl	ftrace_graph_caller
+ftrace_graph_caller:
+	# This unconditional branch gets runtime patched. Change only if
+	# you know what you are doing. See ftrace_enable_graph_caller().
+	j	0f
+	lg	%r2,272(%r15)
+	lg	%r3,168(%r15)
+	brasl	%r14,prepare_ftrace_return
+	stg	%r2,168(%r15)
+0:
+#endif
 	aghi	%r15,160
 	lmg	%r2,%r5,32(%r15)
 	lg	%r14,112(%r15)
@@ -62,6 +74,12 @@ _mcount:
 	larl	%r14,ftrace_trace_function
 	lg	%r14,0(%r14)
 	basr	%r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	lg	%r2,272(%r15)
+	lg	%r3,168(%r15)
+	brasl	%r14,prepare_ftrace_return
+	stg	%r2,168(%r15)
+#endif
 	aghi	%r15,160
 	lmg	%r2,%r5,32(%r15)
 	lg	%r14,112(%r15)
@@ -69,6 +87,22 @@ _mcount:
 
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+	.globl	return_to_handler
+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 /* CONFIG_FUNCTION_GRAPH_TRACER */
+
 #else /* CONFIG_64BIT */
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -96,6 +130,21 @@ ftrace_caller:
 	l	%r14,0b-0b(%r1)
 	l	%r14,0(%r14)
 	basr	%r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	.globl	ftrace_graph_caller
+ftrace_graph_caller:
+	# This unconditional branch gets runtime patched. Change only if
+	# you know what you are doing. See ftrace_enable_graph_caller().
+	j	1f
+	bras	%r1,0f
+	.long	prepare_ftrace_return
+0:	l	%r2,152(%r15)
+	l	%r4,0(%r1)
+	l	%r3,100(%r15)
+	basr	%r14,%r4
+	st	%r2,100(%r15)
+1:
+#endif
 	ahi	%r15,96
 	l	%r14,56(%r15)
 3:	lm	%r2,%r5,16(%r15)
@@ -128,10 +177,40 @@ _mcount:
 	l	%r14,0b-0b(%r1)
 	l	%r14,0(%r14)
 	basr	%r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+	bras	%r1,0f
+	.long	prepare_ftrace_return
+0:	l	%r2,152(%r15)
+	l	%r4,0(%r1)
+	l	%r3,100(%r15)
+	basr	%r14,%r4
+	st	%r2,100(%r15)
+#endif
 	ahi	%r15,96
 	l	%r14,56(%r15)
 3:	lm	%r2,%r5,16(%r15)
 	br	%r14
 
 #endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+	.globl	return_to_handler
+return_to_handler:
+	stm	%r2,%r5,16(%r15)
+	st	%r14,56(%r15)
+	lr	%r0,%r15
+	ahi	%r15,-96
+	st	%r0,__SF_BACKCHAIN(%r15)
+	bras	%r1,0f
+	.long	ftrace_return_to_handler
+0:	l	%r2,0b-0b(%r1)
+	basr	%r14,%r2
+	lr	%r14,%r2
+	ahi	%r15,96
+	lm	%r2,%r5,16(%r15)
+	br	%r14
+
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
 #endif /* CONFIG_64BIT */
-- 
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