[PATCH v5 1/4] kbuild: add mod(name,file)_flags to assembler flags for module objects

[Kris Van Hees]

In order to be able to identify what code is compiled into modules (even
built-in modules) during a kernel build, one can look for the presence
of the -DKBUILD_MODFILE and -DKBUILD_MODNAME options in the compile
command lines.  A simple grep in .*.cmd files for those options is
sufficient for this.

Unfortunately, these options are only passed when compiling C source files.
Various modules also include objects built from assembler source, and these
options are not passed in that case.

Adding $(modfile_flags) to modkern_aflags (similar to modkern_cflahs), and
adding $(modname_flags) to a_flags (similar to c_flags) makes it possible
to identify which objects are compiled into modules for both C and
assembler soure files.

Signed-off-by: Kris Van Hees <kris.van.hees@xxxxxxxxxx>
---
 scripts/Makefile.lib | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/Makefile.lib b/scripts/Makefile.lib
index 9f06f6aaf7fc..f4aec3553ff2 100644
--- a/scripts/Makefile.lib
+++ b/scripts/Makefile.lib
@@ -238,7 +238,7 @@ modkern_rustflags =                                              \
 
 modkern_aflags = $(if $(part-of-module),				\
 			$(KBUILD_AFLAGS_MODULE) $(AFLAGS_MODULE),	\
-			$(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL))
+			$(KBUILD_AFLAGS_KERNEL) $(AFLAGS_KERNEL) $(modfile_flags))
 
 c_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 		 -include $(srctree)/include/linux/compiler_types.h       \
@@ -248,7 +248,7 @@ c_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 rust_flags     = $(_rust_flags) $(modkern_rustflags) @$(objtree)/include/generated/rustc_cfg
 
 a_flags        = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
-		 $(_a_flags) $(modkern_aflags)
+		 $(_a_flags) $(modkern_aflags) $(modname_flags)
 
 cpp_flags      = -Wp,-MMD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE)     \
 		 $(_cpp_flags)
-- 
2.45.1