[S390] cleanup ftrace backend functions

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 7 insertions, 20 deletions

diff --git a/arch/s390/kernel/mcount64.S b/arch/s390/kernel/mcount64.S
index b2bae06ad6c7..e73667286ac0 100644
--- a/arch/s390/kernel/mcount64.S
+++ b/arch/s390/kernel/mcount64.S
@@ -18,12 +18,6 @@ _mcount:
 #ifdef CONFIG_DYNAMIC_FTRACE
         br      %r14
 
-        .data
-        .globl  ftrace_dyn_func
-ftrace_dyn_func:
-        .quad   ftrace_stub
-        .previous
-
         .globl ftrace_caller
 ftrace_caller:
 #endif
@@ -37,26 +31,19 @@ ftrace_caller:
         stg     %r1,__SF_BACKCHAIN(%r15)
         lgr     %r2,%r14
         lg      %r3,168(%r15)
-#ifdef CONFIG_DYNAMIC_FTRACE
-        larl    %r14,ftrace_dyn_func
-#else
         larl    %r14,ftrace_trace_function
-#endif
         lg      %r14,0(%r14)
         basr    %r14,%r14
 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-#ifdef CONFIG_DYNAMIC_FTRACE
+        lg      %r2,168(%r15)
+        lg      %r3,272(%r15)
         .globl  ftrace_graph_caller
 ftrace_graph_caller:
-        # This unconditional branch gets runtime patched. Change only if
-        # you know what you are doing. See ftrace_enable_graph_caller().
-        j       0f
-#endif
-        lg      %r2,272(%r15)
-        lg      %r3,168(%r15)
-        brasl   %r14,prepare_ftrace_return
-        stg     %r2,168(%r15)
-0:
+# The bras instruction gets runtime patched to call prepare_ftrace_return.
+# See ftrace_enable_ftrace_graph_caller. The patched instruction is:
+#       bras    %r14,prepare_ftrace_return
+        bras    %r14,0f
+0:      stg     %r2,168(%r15)
 #endif
         aghi    %r15,160
         lmg     %r2,%r5,32(%r15)