tracing: Add -mcount-nop option support
-mcount-nop gcc option generates the calls to the profiling functions
as nops which allows to avoid patching mcount jump with NOP instructions
initially.
-mcount-nop gcc option will be activated if platform selects
HAVE_NOP_MCOUNT and gcc actually supports it.
In addition to that CC_USING_NOP_MCOUNT is defined and could be used by
architectures to adapt ftrace patching behavior.
Link: http://lkml.kernel.org/r/patch-3.thread-aa7b8d.git-e02ed2dc082b.your-ad-here.call-01533557518-ext-9465@work.hours
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/Makefile b/Makefile
index 2c92ebf..c5b0cd7 100644
--- a/Makefile
+++ b/Makefile
@@ -749,6 +749,12 @@
CC_FLAGS_FTRACE += -mrecord-mcount
export CC_USING_RECORD_MCOUNT := 1
endif
+ ifdef CONFIG_HAVE_NOP_MCOUNT
+ ifeq ($(call cc-option-yn, -mnop-mcount),y)
+ CC_FLAGS_FTRACE += -mnop-mcount
+ CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
+ endif
+ endif
endif
ifdef CONFIG_HAVE_FENTRY
ifeq ($(call cc-option-yn, -mfentry),y)