From: Andi Kleen <a...@linux.intel.com> gcc 5 supports a new -mcount-record option to generate ftrace tables directly. This avoids the need to run record_mcount manually.
Use this option when available. So far doesn't use -mcount-nop, which also exists now. This is needed to make ftrace work with LTO because the normal record-mcount script doesn't run over the link time output. It should also improve build times slightly in the general case. Link: http://lkml.kernel.org/r/20171127213423.27218-12-a...@firstfloor.org Signed-off-by: Andi Kleen <a...@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rost...@goodmis.org> --- scripts/Makefile.build | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 8bdb1dc4072c..dcbca18011bb 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -207,6 +207,11 @@ cmd_modversions_c = \ endif ifdef CONFIG_FTRACE_MCOUNT_RECORD +# gcc 5 supports generating the mcount tables directly +ifneq ($(call cc-option,-mrecord-mcount,y),y) +KBUILD_CFLAGS += -mrecord-mcount +else +# else do it all manually ifdef BUILD_C_RECORDMCOUNT ifeq ("$(origin RECORDMCOUNT_WARN)", "command line") RECORDMCOUNT_FLAGS = -w @@ -259,6 +264,7 @@ ifneq ($(RETPOLINE_CFLAGS),) objtool_args += --retpoline endif endif +endif ifdef CONFIG_MODVERSIONS -- 2.17.0
