sparc64: Allocate sufficient stack space in ftrace stubs.

128 bytes is sufficient for the register window save area, but the
calling conventions allow the callee to save up to 6 incoming argument
registers into the stack frame after the register window save area.

This means a minimal stack frame is 176 bytes (128 + (6 * 8)).

This fixes random crashes when using the function tracer.
Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/lib/mcount.S

@@ -34,7 +34,7 @@ mcount:
 	cmp		%g1, %g2
 	be,pn		%icc, 1f
 	 mov		%i7, %g3
-	save		%sp, -128, %sp
+	save		%sp, -176, %sp
 	mov		%g3, %o1
 	jmpl		%g1, %o7
 	 mov		%i7, %o0
@@ -56,7 +56,7 @@ mcount:
 	 nop
 5:	mov		%i7, %g2
 	mov		%fp, %g3
-	save		%sp, -128, %sp
+	save		%sp, -176, %sp
 	mov		%g2, %l0
 	ba,pt		%xcc, ftrace_graph_caller
 	 mov		%g3, %l1
@@ -85,7 +85,7 @@ ftrace_caller:
 	lduw		[%g1 + %lo(function_trace_stop)], %g1
 	brnz,pn		%g1, ftrace_stub
 	 mov		%fp, %g3
-	save		%sp, -128, %sp
+	save		%sp, -176, %sp
 	mov		%g2, %o1
 	mov		%g2, %l0
 	mov		%g3, %l1
@@ -120,7 +120,7 @@ ENTRY(ftrace_graph_caller)
 END(ftrace_graph_caller)
 
 ENTRY(return_to_handler)
-	save		%sp, -128, %sp
+	save		%sp, -176, %sp
 	call		ftrace_return_to_handler
 	 mov		%fp, %o0
 	jmpl		%o0 + 8, %g0