[S390] ftrace: function tracer backend for s390

This implements just the basic function tracer (_mcount) backend for s390.
The dynamic variant will come later.

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

1 files changed, 56 insertions, 0 deletions

diff --git a/arch/s390/kernel/mcount.S b/arch/s390/kernel/mcount.S
new file mode 100644
index 000000000000..397d131a345f
--- /dev/null
+++ b/arch/s390/kernel/mcount.S
@@ -0,0 +1,56 @@
+/*
+ * Copyright IBM Corp. 2008
+ *
+ *   Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ *
+ */
+
+#ifndef CONFIG_64BIT
+.globl _mcount
+_mcount:
+        stm     %r0,%r5,8(%r15)
+        st      %r14,56(%r15)
+        lr      %r1,%r15
+        ahi     %r15,-96
+        l       %r3,100(%r15)
+        la      %r2,0(%r14)
+        st      %r1,0(%r15)
+        la      %r3,0(%r3)
+        bras    %r14,0f
+        .long   ftrace_trace_function
+0:      l       %r14,0(%r14)
+        l       %r14,0(%r14)
+        basr    %r14,%r14
+        ahi     %r15,96
+        lm      %r0,%r5,8(%r15)
+        l       %r14,56(%r15)
+        br      %r14
+
+.globl ftrace_stub
+ftrace_stub:
+        br      %r14
+
+#else /* CONFIG_64BIT */
+
+.globl _mcount
+_mcount:
+        stmg    %r0,%r5,16(%r15)
+        stg     %r14,112(%r15)
+        lgr     %r1,%r15
+        aghi    %r15,-160
+        stg     %r1,0(%r15)
+        lgr     %r2,%r14
+        lg      %r3,168(%r15)
+        larl    %r14,ftrace_trace_function
+        lg      %r14,0(%r14)
+        basr    %r14,%r14
+        aghi    %r15,160
+        lmg     %r0,%r5,16(%r15)
+        lg      %r14,112(%r15)
+        br      %r14
+
+.globl ftrace_stub
+ftrace_stub:
+        br      %r14
+
+#endif /* CONFIG_64BIT */