microblaze: ftrace: Add dynamic trace support

With dynamic function tracer, by default, _mcount is defined as an
"empty" function, it returns directly without any more action. When
enabling it in user-space, it will jump to a real tracing
function(ftrace_caller), and do the real job for us.

Differ from the static function tracer, dynamic function tracer provides
two functions ftrace_make_call()/ftrace_make_nop() to enable/disable the
tracing of some indicated kernel functions(set_ftrace_filter).

In the kernel version, there is only one "_mcount" string for every
kernel function, so, we just need to match this one in mcount_regex of
scripts/recordmcount.pl.

For more information please look at code and Documentation/trace folder.

Steven ACK that scripts/recordmcount.pl part.

Acked-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Michal Simek <monstr@monstr.eu>

1 files changed, 2 insertions, 0 deletions

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
index cccf3adfae50..102d73aa1063 100644
--- a/arch/microblaze/Kconfig
+++ b/arch/microblaze/Kconfig
@@ -8,6 +8,8 @@ config MICROBLAZE
         select HAVE_LMB
         select HAVE_FUNCTION_TRACER
         select HAVE_FUNCTION_TRACE_MCOUNT_TEST
+        select HAVE_DYNAMIC_FTRACE
+        select HAVE_FTRACE_MCOUNT_RECORD
         select USB_ARCH_HAS_EHCI
         select ARCH_WANT_OPTIONAL_GPIOLIB