sh: ftrace support.

This adds support for ftrace to SH. This only includes CONFIG_FTRACE,
and does not handle dynamic ftrace presently.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/kernel/entry-common.S

@@ -371,3 +371,47 @@ syscall_exit:
 #endif
 7:	.long	do_syscall_trace_enter
 8:	.long	do_syscall_trace_leave
+
+#ifdef CONFIG_FTRACE
+	.align 2
+	.globl	_mcount
+	.type	_mcount,@function
+	.globl	mcount
+	.type	mcount,@function
+_mcount:
+mcount:
+	mov.l	r4, @-r15
+	mov.l	r5, @-r15
+	mov.l	r6, @-r15
+	mov.l	r7, @-r15
+	sts.l	pr, @-r15
+
+	mov.l	@(20,r15),r4
+	sts	pr, r5
+
+	mov.l	1f, r6
+	mov.l	ftrace_stub, r7	
+	cmp/eq	r6, r7
+	bt	skip_trace
+
+	mov.l	@r6, r6
+	jsr	@r6
+	 nop
+
+skip_trace:
+
+	lds.l	@r15+, pr
+	mov.l	@r15+, r7
+	mov.l	@r15+, r6
+	mov.l	@r15+, r5
+	rts
+	 mov.l	@r15+, r4
+
+	.align 2
+1:	.long	ftrace_trace_function
+
+	.globl	ftrace_stub
+ftrace_stub:
+	rts
+	 nop
+#endif /* CONFIG_FTRACE */