MIPS: Tracing: Cleanup the arguments passing of prepare_ftrace_return

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips <linux-mips@linux-mips.org>
Cc: David Daney <david.s.daney@gmail.com>
Patchwork: http://patchwork.linux-mips.org/patch/1226/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 22 insertions, 14 deletions

diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
index e256bf98249a..d4a00d29c0bf 100644
--- a/arch/mips/kernel/mcount.S
+++ b/arch/mips/kernel/mcount.S
@@ -132,28 +132,34 @@ ftrace_stub:
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
 
 NESTED(ftrace_graph_caller, PT_SIZE, ra)
-#ifdef CONFIG_DYNAMIC_FTRACE
-        PTR_L   a1, PT_R31(sp)  /* load the original ra from the stack */
-#ifdef KBUILD_MCOUNT_RA_ADDRESS
-        PTR_L   t0, PT_R12(sp)  /* load the original t0 from the stack */
-#endif
-#else
+#ifndef CONFIG_DYNAMIC_FTRACE
         MCOUNT_SAVE_REGS
-        move    a1, ra          /* arg2: next ip, selfaddr */
 #endif
 
+        /* arg1: Get the location of the parent's return address */
 #ifdef KBUILD_MCOUNT_RA_ADDRESS
-        bnez    t0, 1f          /* non-leaf func: t0 saved the location of the return address */
+#ifdef CONFIG_DYNAMIC_FTRACE
+        PTR_L   a0, PT_R12(sp)
+#else
+        move    a0, t0
+#endif
+        bnez    a0, 1f          /* non-leaf func: stored in t0 */
          nop
-        PTR_LA  t0, PT_R1(sp)   /* leaf func: get the location of at(old ra) from our own stack */
-1:      move    a0, t0          /* arg1: the location of the return address */
+#endif
+        PTR_LA  a0, PT_R1(sp)   /* leaf func: the location in current stack */
+1:
+
+        /* arg2: Get self return address */
+#ifdef CONFIG_DYNAMIC_FTRACE
+        PTR_L   a1, PT_R31(sp)
 #else
-        PTR_LA  a0, PT_R1(sp)   /* arg1: &AT -> a0 */
+        move    a1, ra
 #endif
-        jal     prepare_ftrace_return
+
+        /* arg3: Get frame pointer of current stack */
 #ifdef CONFIG_FRAME_POINTER
-         move   a2, fp          /* arg3: frame pointer */
-#else
+         move   a2, fp
+#else /* ! CONFIG_FRAME_POINTER */
 #ifdef CONFIG_64BIT
          PTR_LA a2, PT_SIZE(sp)
 #else
@@ -161,6 +167,8 @@ NESTED(ftrace_graph_caller, PT_SIZE, ra)
 #endif
 #endif
 
+        jal     prepare_ftrace_return
+         nop
         MCOUNT_RESTORE_REGS
         RETURN_BACK
         END(ftrace_graph_caller)