Currently, KBUILD_MODNAME is defined only when $(modname) contains just one word. If an object is shared among multiple modules, undefined KBUILD_MODNAME could cause a build error. For example, if CONFIG_DYNAMIC_DEBUG is enabled, any call of printk() populates .modname, then fails to build due to undefined KBUILD_MODNAME. Take the following code as an example: obj-m += foo.o obj-m += bar.o foo-objs := foo-bar-common.o foo-main.o bar-objs := foo-bar-common.o bar-main.o In this case, there is room for argument what to define for KBUILD_MODNAME when foo-bar-common.o is being compiled. "foo", "bar", or what else? One idea is to define colon-separated modules that share the object, in this case, "bar:foo" (modules are sorted alphabetically by $(sort ...). Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx> Reviewed-by: Cao jin <caoj.fnst@xxxxxxxxxxxxxx> --- Changes in v2: - Remove comments that will be no longer true scripts/Makefile.lib | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib index 4eedd6e..7feb960 100644 --- a/scripts/Makefile.lib +++ b/scripts/Makefile.lib @@ -87,13 +87,9 @@ subdir-ym := $(addprefix $(obj)/,$(subdir-ym)) # These flags are needed for modversions and compiling, so we define them here # $(modname_flags) defines KBUILD_MODNAME as the name of the module it will # end up in (or would, if it gets compiled in) -# Note: Files that end up in two or more modules are compiled without the -# KBUILD_MODNAME definition. The reason is that any made-up name would -# differ in different configs. name-fix = $(squote)$(quote)$(subst $(comma),_,$(subst -,_,$1))$(quote)$(squote) basename_flags = -DKBUILD_BASENAME=$(call name-fix,$(basetarget)) -modname_flags = $(if $(filter 1,$(words $(modname))),\ - -DKBUILD_MODNAME=$(call name-fix,$(modname))) +modname_flags = -DKBUILD_MODNAME=$(call name-fix,$(modname)) orig_c_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) \ $(ccflags-y) $(CFLAGS_$(basetarget).o) @@ -174,8 +170,10 @@ dtc_cpp_flags = -Wp,-MD,$(depfile).pre.tmp -nostdinc \ -undef -D__DTS__ # Finds the multi-part object the current object will be linked into -modname-multi = $(sort $(foreach m,$(multi-used),\ - $(if $(filter $*.o, $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=)))) +# If the object belongs to two or more multi-part objects, all of them are +# concatenated with a colon separator. +modname-multi = $(subst $(space),:,$(sort $(foreach m,$(multi-used),\ + $(if $(filter $*.o, $($(m:.o=-objs)) $($(m:.o=-y))),$(m:.o=))))) # Useful for describing the dependency of composite objects # Usage: -- 2.7.4 -- 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