From 12f03c6a0d4f4716105f93c62680eb84b1427b6a Mon Sep 17 00:00:00 2001
From: Steven Rostedt <srostedt@redhat.com>
Date: Wed, 11 Feb 2009 12:45:49 -0800
Subject: [PATCH] --- yaml --- r: 138465 b: refs/heads/master c:
 bb7253403f7a4670a128e4c080fd8ea1bd4d5029 h: refs/heads/master i:   138463:
 a5c8210cc921f06b2fed04db79d694cce9a138a1 v: v3

---
 [refs]                               |  2 +-
 trunk/arch/powerpc/kernel/entry_64.S | 27 ++++++++++++++++++++++++++-
 trunk/arch/powerpc/kernel/ftrace.c   | 13 +++++++++++--
 3 files changed, 38 insertions(+), 4 deletions(-)

diff --git a/[refs] b/[refs]
index 3b8555ca2e15..1ddb9a1d6e84 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 465428884765b43d642a967915e16c6c7cacbe8e
+refs/heads/master: bb7253403f7a4670a128e4c080fd8ea1bd4d5029
diff --git a/trunk/arch/powerpc/kernel/entry_64.S b/trunk/arch/powerpc/kernel/entry_64.S
index 9f61fd61f277..abfc32330479 100644
--- a/trunk/arch/powerpc/kernel/entry_64.S
+++ b/trunk/arch/powerpc/kernel/entry_64.S
@@ -970,6 +970,28 @@ _GLOBAL(ftrace_graph_caller)
 	blr
 
 _GLOBAL(return_to_handler)
+	/* need to save return values */
+	std	r4,  -24(r1)
+	std	r3,  -16(r1)
+	std	r31, -8(r1)
+	mr	r31, r1
+	stdu	r1, -112(r1)
+
+	bl	.ftrace_return_to_handler
+	nop
+
+	/* return value has real return address */
+	mtlr	r3
+
+	ld	r1, 0(r1)
+	ld	r4,  -24(r1)
+	ld	r3,  -16(r1)
+	ld	r31, -8(r1)
+
+	/* Jump back to real return address */
+	blr
+
+_GLOBAL(mod_return_to_handler)
 	/* need to save return values */
 	std	r4,  -32(r1)
 	std	r3,  -24(r1)
@@ -979,7 +1001,10 @@ _GLOBAL(return_to_handler)
 	mr	r31, r1
 	stdu	r1, -112(r1)
 
-	/* update the TOC */
+	/*
+	 * We are in a module using the module's TOC.
+	 * Switch to our TOC to run inside the core kernel.
+	 */
 	LOAD_REG_IMMEDIATE(r4,ftrace_return_to_handler)
 	ld	r2, 8(r4)
 
diff --git a/trunk/arch/powerpc/kernel/ftrace.c b/trunk/arch/powerpc/kernel/ftrace.c
index 7538b944fa52..5c6dfa97e838 100644
--- a/trunk/arch/powerpc/kernel/ftrace.c
+++ b/trunk/arch/powerpc/kernel/ftrace.c
@@ -567,6 +567,10 @@ int ftrace_disable_ftrace_graph_caller(void)
 }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+#ifdef CONFIG_PPC64
+extern void mod_return_to_handler(void);
+#endif
+
 /*
  * Hook the return address and push it in the stack of return addrs
  * in current thread info.
@@ -577,12 +581,17 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)
 	unsigned long long calltime;
 	int faulted;
 	struct ftrace_graph_ent trace;
-	unsigned long return_hooker = (unsigned long)
-				&return_to_handler;
+	unsigned long return_hooker = (unsigned long)&return_to_handler;
 
 	if (unlikely(atomic_read(&current->tracing_graph_pause)))
 		return;
 
+#if CONFIG_PPC64
+	/* non core kernel code needs to save and restore the TOC */
+	if (REGION_ID(self_addr) != KERNEL_REGION_ID)
+		return_hooker = (unsigned long)&mod_return_to_handler;
+#endif
+
 	return_hooker = GET_ADDR(return_hooker);
 
 	/*