From 93501b8c8e57436256f4017ea8ef8445f36ea60f Mon Sep 17 00:00:00 2001
From: "David S. Miller" <davem@davemloft.net>
Date: Mon, 12 Apr 2010 22:35:24 -0700
Subject: [PATCH] --- yaml --- r: 189870 b: refs/heads/master c:
 63b754957371c23b7515399a977a2e1d361a036c h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/arch/sparc/Kconfig      |  1 +
 trunk/arch/sparc/lib/mcount.S | 22 +++++++++++++++-------
 3 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/[refs] b/[refs]
index 94a9e52a7f68..1ff652095c1d 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 0c25e9e6cbe7b233bb91d14d0e2c258bf8e6ec83
+refs/heads/master: 63b754957371c23b7515399a977a2e1d361a036c
diff --git a/trunk/arch/sparc/Kconfig b/trunk/arch/sparc/Kconfig
index 6db513674050..035304c30ab4 100644
--- a/trunk/arch/sparc/Kconfig
+++ b/trunk/arch/sparc/Kconfig
@@ -37,6 +37,7 @@ config SPARC64
 	def_bool 64BIT
 	select ARCH_SUPPORTS_MSI
 	select HAVE_FUNCTION_TRACER
+	select HAVE_FUNCTION_TRACE_MCOUNT_TEST
 	select HAVE_KRETPROBES
 	select HAVE_KPROBES
 	select HAVE_LMB
diff --git a/trunk/arch/sparc/lib/mcount.S b/trunk/arch/sparc/lib/mcount.S
index 24b8b12deed2..7047997be0eb 100644
--- a/trunk/arch/sparc/lib/mcount.S
+++ b/trunk/arch/sparc/lib/mcount.S
@@ -96,13 +96,12 @@ mcount:
 #endif
 #ifdef CONFIG_FUNCTION_TRACER
 #ifdef CONFIG_DYNAMIC_FTRACE
-	mov		%o7, %o0
-	.globl		mcount_call
-mcount_call:
-	call		ftrace_stub
-	 mov		%o0, %o7
+	/* Do nothing, the retl/nop below is all we need.  */
 #else
-	sethi		%hi(ftrace_trace_function), %g1
+	sethi		%hi(function_trace_stop), %g1
+	lduw		[%g1 + %lo(function_trace_stop)], %g2
+	brnz,pn		%g2, 1f
+	 sethi		%hi(ftrace_trace_function), %g1
 	sethi		%hi(ftrace_stub), %g2
 	ldx		[%g1 + %lo(ftrace_trace_function)], %g1
 	or		%g2, %lo(ftrace_stub), %g2
@@ -131,14 +130,23 @@ ftrace_stub:
 	.globl		ftrace_caller
 	.type		ftrace_caller,#function
 ftrace_caller:
+	sethi		%hi(function_trace_stop), %g1
 	mov		%i7, %o1
-	mov		%o7, %o0
+	lduw		[%g1 + %lo(function_trace_stop)], %g2
+	brnz,pn		%g2, ftrace_stub
+	 mov		%o7, %o0
 	.globl		ftrace_call
 ftrace_call:
+	/* If the final kernel link ever turns on relaxation, we'll need
+	 * to do something about this tail call.  Otherwise the linker
+	 * will rewrite the call into a branch and nop out the move
+	 * instruction.
+	 */
 	call		ftrace_stub
 	 mov		%o0, %o7
 	retl
 	 nop
+	.size		ftrace_call,.-ftrace_call
 	.size		ftrace_caller,.-ftrace_caller
 #endif
 #endif