[S390] ftrace: add function graph tracer support

Function graph tracer support for s390.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
index 0aa85ec94d08..2a0a5e97ba8c 100644
--- a/arch/s390/kernel/mcount.S
+++ b/arch/s390/kernel/mcount.S
@@ -34,6 +34,18 @@ ftrace_caller:
         larl    %r14,ftrace_dyn_func
         lg      %r14,0(%r14)
         basr    %r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        .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
+        lg      %r2,272(%r15)
+        lg      %r3,168(%r15)
+        brasl   %r14,prepare_ftrace_return
+        stg     %r2,168(%r15)
+0:
+#endif
         aghi    %r15,160
         lmg     %r2,%r5,32(%r15)
         lg      %r14,112(%r15)
@@ -62,6 +74,12 @@ _mcount:
         larl    %r14,ftrace_trace_function
         lg      %r14,0(%r14)
         basr    %r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        lg      %r2,272(%r15)
+        lg      %r3,168(%r15)
+        brasl   %r14,prepare_ftrace_return
+        stg     %r2,168(%r15)
+#endif
         aghi    %r15,160
         lmg     %r2,%r5,32(%r15)
         lg      %r14,112(%r15)
@@ -69,6 +87,22 @@ _mcount:
 
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+        .globl  return_to_handler
+return_to_handler:
+        stmg    %r2,%r5,32(%r15)
+        lgr     %r1,%r15
+        aghi    %r15,-160
+        stg     %r1,__SF_BACKCHAIN(%r15)
+        brasl   %r14,ftrace_return_to_handler
+        aghi    %r15,160
+        lgr     %r14,%r2
+        lmg     %r2,%r5,32(%r15)
+        br      %r14
+
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
 #else /* CONFIG_64BIT */
 
 #ifdef CONFIG_DYNAMIC_FTRACE
@@ -96,6 +130,21 @@ ftrace_caller:
         l       %r14,0b-0b(%r1)
         l       %r14,0(%r14)
         basr    %r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        .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       1f
+        bras    %r1,0f
+        .long   prepare_ftrace_return
+0:      l       %r2,152(%r15)
+        l       %r4,0(%r1)
+        l       %r3,100(%r15)
+        basr    %r14,%r4
+        st      %r2,100(%r15)
+1:
+#endif
         ahi     %r15,96
         l       %r14,56(%r15)
 3:      lm      %r2,%r5,16(%r15)
@@ -128,10 +177,40 @@ _mcount:
         l       %r14,0b-0b(%r1)
         l       %r14,0(%r14)
         basr    %r14,%r14
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+        bras    %r1,0f
+        .long   prepare_ftrace_return
+0:      l       %r2,152(%r15)
+        l       %r4,0(%r1)
+        l       %r3,100(%r15)
+        basr    %r14,%r4
+        st      %r2,100(%r15)
+#endif
         ahi     %r15,96
         l       %r14,56(%r15)
 3:      lm      %r2,%r5,16(%r15)
         br      %r14
 
 #endif /* CONFIG_DYNAMIC_FTRACE */
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+
+        .globl  return_to_handler
+return_to_handler:
+        stm     %r2,%r5,16(%r15)
+        st      %r14,56(%r15)
+        lr      %r0,%r15
+        ahi     %r15,-96
+        st      %r0,__SF_BACKCHAIN(%r15)
+        bras    %r1,0f
+        .long   ftrace_return_to_handler
+0:      l       %r2,0b-0b(%r1)
+        basr    %r14,%r2
+        lr      %r14,%r2
+        ahi     %r15,96
+        lm      %r2,%r5,16(%r15)
+        br      %r14
+
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
+
 #endif /* CONFIG_64BIT */