microblaze: ftrace: Add dynamic function graph tracer
This patch add support for dynamic function graph tracer.
There is one my expactation that I can do flush_icache after
all code modification. On microblaze is this safer than do
flush for every entry. For icache is used name flush but
correct should be invalidation - this will be fix in upcomming
new cache implementaion and WB support.
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/kernel/ftrace.c b/arch/microblaze/kernel/ftrace.c
index 0952a8b..388b31c 100644
--- a/arch/microblaze/kernel/ftrace.c
+++ b/arch/microblaze/kernel/ftrace.c
@@ -206,4 +206,32 @@
return ret;
}
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+unsigned int old_jump; /* saving place for jump instruction */
+
+int ftrace_enable_ftrace_graph_caller(void)
+{
+ unsigned int ret;
+ unsigned long ip = (unsigned long)(&ftrace_call_graph);
+
+ old_jump = *(unsigned int *)ip; /* save jump over instruction */
+ ret = ftrace_modify_code(ip, MICROBLAZE_NOP);
+ flush_icache();
+
+ pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);
+ return ret;
+}
+
+int ftrace_disable_ftrace_graph_caller(void)
+{
+ unsigned int ret;
+ unsigned long ip = (unsigned long)(&ftrace_call_graph);
+
+ ret = ftrace_modify_code(ip, old_jump);
+ flush_icache();
+
+ pr_debug("%s\n", __func__);
+ return ret;
+}
+#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#endif /* CONFIG_DYNAMIC_FTRACE */
diff --git a/arch/microblaze/kernel/mcount.S b/arch/microblaze/kernel/mcount.S
index 84a1945..e7eaa7a 100644
--- a/arch/microblaze/kernel/mcount.S
+++ b/arch/microblaze/kernel/mcount.S
@@ -97,6 +97,7 @@
nop;
/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+#ifndef CONFIG_DYNAMIC_FTRACE
lwi r5, r0, ftrace_graph_return;
addik r6, r0, ftrace_stub; /* asm implementation */
cmpu r5, r5, r6; /* ftrace_graph_return != ftrace_stub */
@@ -108,6 +109,11 @@
cmpu r5, r5, r6; /* ftrace_graph_entry != ftrace_graph_entry_stub */
beqid r5, end_graph_tracer;
nop;
+#else /* CONFIG_DYNAMIC_FTRACE */
+NOALIGN_ENTRY(ftrace_call_graph)
+ /* MS: jump over graph function - replaced from C code */
+ bri end_graph_tracer
+#endif /* CONFIG_DYNAMIC_FTRACE */
addik r5, r1, 120; /* MS: load parent addr */
addik r6, r15, 0; /* MS: load current function addr */
bralid r15, prepare_ftrace_return;
