MIPS: Tracing: Make ftrace for MIPS work without -fno-omit-frame-pointer

When remove the -fno-omit-frame-pointer, gcc will not save the frame
pointer for us, we need to save one ourselves.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Nicholas Mc Guire <der.herr@hofr.at>
Cc: zhangfx@lemote.com
Cc: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: http://patchwork.linux-mips.org/patch/679/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
index 98d469032506..bdfef2c24f16 100644
--- a/arch/mips/kernel/mcount.S
+++ b/arch/mips/kernel/mcount.S
@@ -139,7 +139,15 @@ NESTED(ftrace_graph_caller, PT_SIZE, ra)
 #endif
         PTR_LA  a0, PT_R1(sp)   /* arg1: &AT -> a0 */
         jal     prepare_ftrace_return
+#ifdef CONFIG_FRAME_POINTER
          move   a2, fp          /* arg3: frame pointer */
+#else
+#ifdef CONFIG_64BIT
+         PTR_LA a2, PT_SIZE(sp)
+#else
+         PTR_LA a2, (PT_SIZE+8)(sp)
+#endif
+#endif
 
         MCOUNT_RESTORE_REGS
         RETURN_BACK