From f9a03bb58aa222824b3041efbf62488af693feaa Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Mon, 27 Nov 2017 13:34:13 -0800 Subject: [PATCH 1/2] trace: Use -mcount-record for dynamic ftrace 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-andi@firstfloor.org Signed-off-by: Andi Kleen Signed-off-by: Steven Rostedt (VMware) --- scripts/Makefile.build | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 42aef001dfdd..fff1452cb76e 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -221,6 +221,11 @@ 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 @@ -250,6 +255,7 @@ cmd_record_mcount = \ $(sub_cmd_record_mcount) \ fi; endif +endif define rule_cc_o_c $(call echo-cmd,checksrc) $(cmd_checksrc) \ -- 2.30.1