microblaze: ftrace: add function graph support
For more information look at Documentation/trace folder.
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/kernel/mcount.S b/arch/microblaze/kernel/mcount.S
index 30aaf8f..84a1945 100644
--- a/arch/microblaze/kernel/mcount.S
+++ b/arch/microblaze/kernel/mcount.S
@@ -96,6 +96,27 @@
bneid r5, end;
nop;
/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ lwi r5, r0, ftrace_graph_return;
+ addik r6, r0, ftrace_stub; /* asm implementation */
+ cmpu r5, r5, r6; /* ftrace_graph_return != ftrace_stub */
+ beqid r5, end_graph_tracer;
+ nop;
+
+ lwi r6, r0, ftrace_graph_entry;
+ addik r5, r0, ftrace_graph_entry_stub; /* implemented in C */
+ cmpu r5, r5, r6; /* ftrace_graph_entry != ftrace_graph_entry_stub */
+ beqid r5, end_graph_tracer;
+ nop;
+ addik r5, r1, 120; /* MS: load parent addr */
+ addik r6, r15, 0; /* MS: load current function addr */
+ bralid r15, prepare_ftrace_return;
+ nop;
+ /* MS: graph was taken that's why - can jump over function trace */
+ brid end;
+ nop;
+end_graph_tracer:
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#ifndef CONFIG_DYNAMIC_FTRACE
/* MS: test function trace if is taken or not */
lwi r20, r0, ftrace_trace_function;
@@ -121,3 +142,23 @@
rtsd r15, 8; /* MS: jump back */
nop;
+
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ENTRY(return_to_handler)
+ nop; /* MS: just barrier for rtsd r15, 8 */
+ nop;
+ SAVE_REGS
+ swi r15, r1, 0;
+
+ /* MS: find out returning address */
+ bralid r15, ftrace_return_to_handler;
+ nop;
+
+ /* MS: return value from ftrace_return_to_handler is my returning addr
+ * must be before restore regs because I have to restore r3 content */
+ addik r15, r3, 0;
+ RESTORE_REGS
+
+ rtsd r15, 8; /* MS: jump back */
+ nop;
+#endif /* CONFIG_FUNCTION_TRACER */