Re: [RFC][PATCH 2/2] ftrace/kbuild: Add recordmcount files to force full build

Michal Marek
2011-05-17T13:36:49Z

On Mon, May 16, 2011 at 10:10:29PM -0400, Steven Rostedt wrote:
> From: Steven Rostedt <srostedt@redhat.com>
>
> Modifications to recordmcount must be performed on all object
> files to stay consistent with what the kernel code may expect.
> Add the recordmcount files to the force-deps to make sure
> any change to them causes a full recompile.
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
> ---
> scripts/Makefile.build | 2 ++
> 1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/scripts/Makefile.build b/scripts/Makefile.build
> index 0ff5a58..057d6e9 100644
> --- a/scripts/Makefile.build
> +++ b/scripts/Makefile.build
> @@ -252,6 +252,7 @@ sub_cmd_record_mcount = \
> if [ $(@) != "scripts/mod/empty.o" ]; then \
> $(objtree)/scripts/recordmcount "$(@)"; \
> fi;
> +force-deps += $(srctree)/scripts/recordmcount.c $(srctree)/scripts/recordmcount.h
> else
> sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
> "$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
> @@ -259,6 +260,7 @@ sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH
> "$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
> "$(LD)" "$(NM)" "$(RM)" "$(MV)" \
> "$(if $(part-of-module),1,0)" "$(@)";
> +force-deps += $(srctree)/scripts/recordmcount.pl
> endif
> cmd_record_mcount = \
> if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \

We could add recordmcount.c as a dependency in scripts/Makefile.build
directly, without playing with fixdep, like this (untested):

diff --git a/scripts/Makefile.build b/scripts/Makefile.build
index f133641..bc2c8d3 100644
--- a/scripts/Makefile.build
+++ b/scripts/Makefile.build
@@ -268,6 +268,7 @@ sub_cmd_record_mcount = \
if [ $(@) != "scripts/mod/empty.o" ]; then \
$(objtree)/scripts/recordmcount "$(@)"; \
fi;
+recordmcount_source := $(srctree)/scripts/recordmcount.c
else
sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH)" \
"$(if $(CONFIG_CPU_BIG_ENDIAN),big,little)" \
@@ -275,6 +276,7 @@ sub_cmd_record_mcount = set -e ; perl $(srctree)/scripts/recordmcount.pl "$(ARCH
"$(OBJDUMP)" "$(OBJCOPY)" "$(CC) $(KBUILD_CFLAGS)" \
"$(LD)" "$(NM)" "$(RM)" "$(MV)" \
"$(if $(part-of-module),1,0)" "$(@)";
+recordmcount_source := $(srctree)/scripts/recordmcount.pl
endif
cmd_record_mcount = \
if [ "$(findstring -pg,$(_c_flags))" = "-pg" ]; then \
@@ -295,13 +297,13 @@ define rule_cc_o_c
endef

# Built-in and composite module parts
-$(obj)/%.o: $(src)/%.c FORCE
+$(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)

# Single-part modules are special since we need to mark them in $(MODVERDIR)

-$(single-used-m): $(obj)/%.o: $(src)/%.c FORCE
+$(single-used-m): $(obj)/%.o: $(src)/%.c $(recordmcount_source) FORCE
$(call cmd,force_checksrc)
$(call if_changed_rule,cc_o_c)
@{ echo $(@:.o=.ko); echo $@; } > $(MODVERDIR)/$(@F:.o=.mod)

Michal