From 8b41fc4454e36fbfdbb23f940d023d4dece2de29 Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Thu, 19 Dec 2019 17:33:29 +0900 Subject: kbuild: create modules.builtin without Makefile.modbuiltin or tristate.conf Commit bc081dd6e9f6 ("kbuild: generate modules.builtin") added infrastructure to generate modules.builtin, the list of all builtin modules. Basically, it works like this: - Kconfig generates include/config/tristate.conf, the list of tristate CONFIG options with a value in a capital letter. - scripts/Makefile.modbuiltin makes Kbuild descend into directories to collect the information of builtin modules. I am not a big fan of it because Kbuild ends up with traversing the source tree twice. I am not sure how perfectly it should work, but this approach cannot avoid false positives; even if the relevant CONFIG option is tristate, some Makefiles forces obj-m to obj-y. Some examples are: arch/powerpc/platforms/powermac/Makefile: obj-$(CONFIG_NVRAM:m=y) += nvram.o net/ipv6/Makefile: obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o net/netlabel/Makefile: obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o Nobody has complained about (or noticed) it, so it is probably fine to have false positives in modules.builtin. This commit simplifies the implementation. Let's exploit the fact that every module has MODULE_LICENSE(). (modpost shows a warning if MODULE_LICENSE is missing. If so, 0-day bot would already have blocked such a module.) I added MODULE_FILE to . When the code is being compiled as builtin, it will be filled with the file path of the module, and collected into modules.builtin.info. Then, scripts/link-vmlinux.sh extracts the list of builtin modules out of it. This new approach fixes the false-positives above, but adds another type of false-positives; non-modular code may have MODULE_LICENSE() by mistake. This is not a big deal, it is just the code is always orphan. We can clean it up if we like. You can see cleanup examples by: $ git log --grep='make.* explicitly non-modular' To sum up, this commits deletes lots of code, but still produces almost equivalent results. Please note it does not increase the vmlinux size at all. As you can see in include/asm-generic/vmlinux.lds.h, the .modinfo section is discarded in the link stage. Signed-off-by: Masahiro Yamada --- include/linux/module.h | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/module.h b/include/linux/module.h index bd165ba68617..6877b3b191d0 100644 --- a/include/linux/module.h +++ b/include/linux/module.h @@ -169,6 +169,16 @@ extern void cleanup_module(void); */ #define MODULE_SOFTDEP(_softdep) MODULE_INFO(softdep, _softdep) +/* + * MODULE_FILE is used for generating modules.builtin + * So, make it no-op when this is being built as a module + */ +#ifdef MODULE +#define MODULE_FILE +#else +#define MODULE_FILE MODULE_INFO(file, KBUILD_MODFILE); +#endif + /* * The following license idents are currently accepted as indicating free * software modules @@ -213,7 +223,7 @@ extern void cleanup_module(void); * 2. So the community can ignore bug reports including proprietary modules * 3. So vendors can do likewise based on their own policies */ -#define MODULE_LICENSE(_license) MODULE_INFO(license, _license) +#define MODULE_LICENSE(_license) MODULE_FILE MODULE_INFO(license, _license) /* * Author(s), use "Name " or just "Name", for multiple -- cgit v1.2.3