From 69bc8d386aebbd91a6bb44b6d33f77c8dfa9ed8c Mon Sep 17 00:00:00 2001 From: Masahiro Yamada Date: Fri, 26 Mar 2021 03:54:09 +0900 Subject: [PATCH] kbuild: generate Module.symvers only when vmlinux exists The external module build shows the following warning if Module.symvers is missing in the kernel tree. WARNING: Symbol version dump "Module.symvers" is missing. Modules may not have dependencies or modversions. I think this is an important heads-up because the resulting modules may not work as expected. This happens when you did not build the entire kernel tree, for example, you might have prepared the minimal setups for external modules by 'make defconfig && make modules_preapre'. A problem is that 'make modules' creates Module.symvers even without vmlinux. In this case, that warning is suppressed since Module.symvers already exists in spite of its incomplete content. The incomplete (i.e. invalid) Module.symvers should not be created. This commit changes the second pass of modpost to dump symbols into modules-only.symvers. The final Module.symvers is created by concatenating vmlinux.symvers and modules-only.symvers if both exist. Module.symvers is supposed to collect symbols from both vmlinux and modules. It might be a bit confusing, and I am not quite sure if it is an official interface, but presumably it is difficult to rename it because some tools (e.g. kmod) parse it. Signed-off-by: Masahiro Yamada --- .gitignore | 1 + Documentation/dontdiff | 1 + Makefile | 2 +- scripts/Makefile.modpost | 15 ++++++++++++++- scripts/mod/modpost.c | 15 +-------------- 5 files changed, 18 insertions(+), 16 deletions(-) diff --git a/.gitignore b/.gitignore index 3adea59847ce..df8d3146a43f 100644 --- a/.gitignore +++ b/.gitignore @@ -57,6 +57,7 @@ modules.order /tags /TAGS /linux +/modules-only.symvers /vmlinux /vmlinux.32 /vmlinux.map diff --git a/Documentation/dontdiff b/Documentation/dontdiff index ac42ad8d430d..910b30a2a7d9 100644 --- a/Documentation/dontdiff +++ b/Documentation/dontdiff @@ -178,6 +178,7 @@ mktables mktree mkutf8data modpost +modules-only.symvers modules.builtin modules.builtin.modinfo modules.nsdeps diff --git a/Makefile b/Makefile index 2b161f5a5a66..ed8bd815e8a3 100644 --- a/Makefile +++ b/Makefile @@ -1532,7 +1532,7 @@ endif # CONFIG_MODULES # make distclean Remove editor backup files, patch leftover files and the like # Directories & files removed with 'make clean' -CLEAN_FILES += include/ksym vmlinux.symvers \ +CLEAN_FILES += include/ksym vmlinux.symvers modules-only.symvers \ modules.builtin modules.builtin.modinfo modules.nsdeps \ compile_commands.json .thinlto-cache diff --git a/scripts/Makefile.modpost b/scripts/Makefile.modpost index df57e259fac3..3f5b09a09aef 100644 --- a/scripts/Makefile.modpost +++ b/scripts/Makefile.modpost @@ -68,7 +68,20 @@ else ifeq ($(KBUILD_EXTMOD),) input-symdump := vmlinux.symvers -output-symdump := Module.symvers +output-symdump := modules-only.symvers + +quiet_cmd_cat = GEN $@ + cmd_cat = cat $(real-prereqs) > $@ + +ifneq ($(wildcard vmlinux.symvers),) + +__modpost: Module.symvers +Module.symvers: vmlinux.symvers modules-only.symvers FORCE + $(call if_changed,cat) + +targets += Module.symvers + +endif else diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 24725e50c7b4..10c3fba26f03 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -2423,19 +2423,6 @@ fail: fatal("parse error in symbol dump file\n"); } -/* For normal builds always dump all symbols. - * For external modules only dump symbols - * that are not read from kernel Module.symvers. - **/ -static int dump_sym(struct symbol *sym) -{ - if (!external_module) - return 1; - if (sym->module->from_dump) - return 0; - return 1; -} - static void write_dump(const char *fname) { struct buffer buf = { }; @@ -2446,7 +2433,7 @@ static void write_dump(const char *fname) for (n = 0; n < SYMBOL_HASH_SIZE ; n++) { symbol = symbolhash[n]; while (symbol) { - if (dump_sym(symbol)) { + if (!symbol->module->from_dump) { namespace = symbol->namespace; buf_printf(&buf, "0x%08x\t%s\t%s\t%s\t%s\n", symbol->crc, symbol->name,