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: CFLAGS_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@goodmis.org>) Acked-by: Michal Marek <mmarek@suse.cz> Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com> LKML-Reference: <3dc8cddf022eb7024f9f2cf857529a15bee8999a.1288196498.git.wuzhangjin@gmail.com> [ changed if [ .. == .. ] to if [ .. = .. ] to handle dash environments ]
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| @@ -214,17 +214,22 @@ ifdef BUILD_C_RECORDMCOUNT · 213 unmodified lines | ||
| 214 | 214 | # The empty.o file is created in the make process in order to determine |
| 215 | 215 | # the target endianness and word size. It is made before all other C |
| 216 | 216 | # files, including recordmcount. |
| 217 | −cmd_record_mcount = if [ $(@) != "scripts/mod/empty.o" ]; then \ | |
| 218 | − $(objtree)/scripts/recordmcount "$(@)"; \ | |
| 219 | − fi; | |
| 217 | +sub_cmd_record_mcount = \ | |
| 218 | + if [ $(@) != "scripts/mod/empty.o" ]; then \ | |
| 219 | + $(objtree)/scripts/recordmcount "$(@)"; \ | |
| 220 | + fi; | |
| 220 | 221 | else |
| 221 | −cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ | |
| 222 | +sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \ | |
| 222 | 223 | "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \ |
| 223 | 224 | "$(if $(CONFIG_64BIT),64,32)" \ |
| 224 | 225 | "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \ |
| 225 | 226 | "$(LD)" "$(NM)" "$(RM)" "$(MV)" \ |
| 226 | 227 | "$(if $(part-of-module),1,0)" "$(@)"; |
| 227 | 228 | endif |
| 229 | +cmd_record_mcount = \ | |
| 230 | + if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \ | |
| 231 | + $(sub_cmd_record_mcount) \ | |
| 232 | + fi; | |
| 228 | 233 | endif |
| 229 | 234 | |
| 230 | 235 | define rule_cc_o_c |