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authorAndi Kleen <ak@linux.intel.com>2017-11-27 13:34:13 -0800
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2018-05-28 12:49:51 -0400
commit96f60dfa5819a065bfdd2f2ba0df7d9cbce7f4dd (patch)
tree98102816257e20f2be705a016b7049d16b159636 /scripts/Makefile.build
parent2824f5033248600673e3e126a4d135363cbfd9ac (diff)
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 <ak@linux.intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'scripts/Makefile.build')
-rw-r--r--scripts/Makefile.build6
1 files changed, 6 insertions, 0 deletions
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