tracing: Allow gcov profiling on only ftrace subsystem

Add GCOV_PROFILE_FTRACE to allow gcov profiling on only files in ftrace
subsystem. This config option will be used for checking kselftest/ftrace
coverage.

Link: http://lkml.kernel.org/r/153483647755.32472.4746349899604275441.stgit@devbox
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index fd6754b88f87cfca499ec1dc7549cd8f2449f738..aec44d838283faf342b964627999b1f00538d162 100644 (file)
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -774,6 +774,18 @@ config TRACING_EVENTS_GPIO
        help
          Enable tracing events for gpio subsystem
 
+config GCOV_PROFILE_FTRACE
+       bool "Enable GCOV profiling on ftrace subsystem"
+       depends on GCOV_KERNEL
+       help
+         Enable GCOV profiling on ftrace subsystem for checking
+         which functions/lines are tested.
+
+         If unsure, say N.
+
+         Note that on a kernel compiled with this config, ftrace will
+         run significantly slower.
+
 endif # FTRACE
 
 endif # TRACING_SUPPORT

diff --git a/kernel/trace/Makefile b/kernel/trace/Makefile
index 98d53b39a8ee333e130e4d53cb5a3992191ea6a7..f81dadbc7c4ac3ef35c031d1164edf1b3b82d034 100644 (file)
--- a/kernel/trace/Makefile
+++ b/kernel/trace/Makefile
@@ -23,6 +23,11 @@ ifdef CONFIG_TRACING_BRANCHES
 KBUILD_CFLAGS += -DDISABLE_BRANCH_PROFILING
 endif
 
+# for GCOV coverage profiling
+ifdef CONFIG_GCOV_PROFILE_FTRACE
+GCOV_PROFILE := y
+endif
+
 CFLAGS_trace_benchmark.o := -I$(src)
 CFLAGS_trace_events_filter.o := -I$(src)