1 files changed, 42 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S
index fd54cb59728e..12247b937d25 100644
--- a/arch/powerpc/kernel/entry_32.S
+++ b/arch/powerpc/kernel/entry_32.S
@@ -1199,9 +1199,11 @@ _GLOBAL(_mcount)
 
         mtctr   r5
         bctrl
-
         nop
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        b       ftrace_graph_caller
+#endif
         MCOUNT_RESTORE_FRAME
         
         bctr
@@ -1210,4 +1212,43 @@ _GLOBAL(_mcount)
 _GLOBAL(ftrace_stub)
         blr
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+_GLOBAL(ftrace_graph_caller)
+        /* load r4 with local address */
+        lwz     r4, 44(r1)
+        subi    r4, r4, MCOUNT_INSN_SIZE
+
+        /* get the parent address */
+        addi    r3, r1, 52
+
+        bl      prepare_ftrace_return
+        nop
+
+        MCOUNT_RESTORE_FRAME
+        /* old link register ends up in ctr reg */
+        bctr
+
+_GLOBAL(return_to_handler)
+        /* need to save return values */
+        stwu    r1, -32(r1)
+        stw     r3, 20(r1)
+        stw     r4, 16(r1)
+        stw     r31, 12(r1)
+        mr      r31, r1
+
+        bl      ftrace_return_to_handler
+        nop
+
+        /* return value has real return address */
+        mtlr    r3
+
+        lwz     r3, 20(r1)
+        lwz     r4, 16(r1)
+        lwz     r31,12(r1)
+        lwz     r1, 0(r1)
+
+        /* Jump back to real return address */
+        blr
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
 #endif /* CONFIG_MCOUNT */