From: Wu Zhangjin <wuzhangjin@xxxxxxxxx> cmd_record_mcount is used to locate the _mcount symbols in the object files, only the files compiled with -pg has the _mcount symbol, so, it is only needed for such files, but the current cmd_record_mcount is used for all of the object files, so, we need to fix it and speed it up. Since -pg may be removed by the method used in kernel/trace/Makefile: ORIG_CFLAGS := $(KBUILD_CFLAGS) KBUILD_CFLAGS = $(subst -pg,,$(ORIG_CFLAGS)) Or may be removed by the method used in arch/x86/kernel/Makefile: CONFIG_REMOVE_file.o = -pg So, we must check the last variable stores the compiling flags, that is c_flags(Please refer to cmd_cc_o_c and rule_cc_o_c defined in scripts/Makefile.build) and since the CFLAGS_REMOVE_file.o is already filtered in _c_flags(Please refer to scripts/Makefile.lib) and _c_flags has less symbols, therefore, we only need to check _c_flags. --------------- Changes from v1: o Don't touch Makefile for CONFIG_FTRACE_MCOUNT_RECORD is enough o Use _c_flags intead of KBUILD_CFLAGS to cover CONFIG_REMOVE_file.o = -pg (feedback from Steven Rostedt <rostedt@xxxxxxxxxxx>) Signed-off-by: Wu Zhangjin <wuzhangjin@xxxxxxxxx> --- scripts/Makefile.build | 13 +++++++++---- 1 files changed, 9 insertions(+), 4 deletions(-) diff --git a/scripts/Makefile.build b/scripts/Makefile.build index 5ad25e1..0ad6108 100644 --- a/scripts/Makefile.build +++ b/scripts/Makefile.build @@ -214,17 +214,22 @@ ifdef BUILD_C_RECORDMCOUNT # The empty.o file is created in the make process in order to determine # the target endianness and word size. It is made before all other C # files, including recordmcount. -cmd_record_mcount = if [ $(@) != "scripts/mod/empty.o" ]; then \ - $(objtree)/scripts/recordmcount "$(@)"; \ - fi; +sub_cmd_record_mcount = \ + if [ $(@) != "scripts/mod/empty.o" ]; then \ + $(objtree)/scripts/recordmcount "$(@)"; \ + fi; else -cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ +sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ "$(if $(CONFIG_64BIT),64,32)" \ "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ "$(LD)" "$(NM)" "$(RM)" "$(MV)" \ "$(if $(part-of-module),1,0)" "$(@)"; endif +cmd_record_mcount = \ + if [ "$(findstring -pg,$(_c_flags))" == "-pg" ]; then \ + $(sub_cmd_record_mcount) \ + fi; endif define rule_cc_o_c -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
