microblaze: ftrace: add static function tracer
If -pg of gcc is enabled with CONFIG_FUNCTION_TRACER=y. a calling to
_mcount will be inserted into each kernel function. so, there is a
possibility to trace the kernel functions in _mcount.
This patch add the specific _mcount support for static function
tracing. by default, ftrace_trace_function is initialized as
ftrace_stub(an empty function), so, the default _mcount will introduce
very little overhead. after enabling ftrace in user-space, it will jump
to a real tracing function and do static function tracing for us.
Commit message from Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Michal Simek <monstr@monstr.eu>
diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index 57eeaa6..18003ca 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -6,6 +6,7 @@
config MICROBLAZE
def_bool y
select HAVE_LMB
+ select HAVE_FUNCTION_TRACER
select USB_ARCH_HAS_EHCI
select ARCH_WANT_OPTIONAL_GPIOLIB