kernel/linux.git/scripts/Makefile.modpost, branch v6.6.132

linux/export.h: make independent of CONFIG_MODULES

2023-07-24T15:59:32+00:00

Currently, all files with EXPORT_SYMBOL() are rebuilt when CONFIG_MODULES is flipped due to depending on CONFIG_MODULES. Now that modpost can make a final decision about export symbols, does not need to make EXPORT_SYMBOL() no-op. Instead, modpost can skip emitting KSYMTAB when CONFIG_MODULES is unset. This commit will reduce the number of recompilation when CONFIG_MODULES is toggled. Signed-off-by: Masahiro Yamada

kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion

2023-06-22T12:21:06+00:00

When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada

modpost: propagate W=1 build option to modpost

2023-06-07T13:41:08+00:00

"No build warning" is a strong requirement these days, so you must fix all issues before enabling a new warning flag. We often add a new warning to W=1 first so that the kbuild test robot blocks new breakages. This commit allows modpost to show extra warnings only when W=1 (or KBUILD_EXTRA_WARN=1) is given. Signed-off-by: Masahiro Yamada Reviewed-by: Nick Desaulniers

kbuild: do not automatically add -w option to modpost

2023-02-05T09:51:22+00:00

When there is a missing input file (vmlinux.o or Module.symvers), you are likely to get a ton of unresolved symbols. Currently, Kbuild automatically adds the -w option to allow module builds to continue with warnings instead of errors. This may not be what the user expects because it is generally more useful to catch all possible issues at build time instead of at run time. Let's not do what the user did not ask. If you still want to build modules anyway, you can proceed by explicitly setting KBUILD_MODPOST_WARN=1. Since you may miss a real issue, you need to be aware of what you are doing. Suggested-by: William McVicker Signed-off-by: Masahiro Yamada Tested-by: Will McVicker

kbuild: readd -w option when vmlinux.o or Module.symver is missing

2023-01-05T07:53:48+00:00

Commit 63ffe00d8c93 ("kbuild: Fix running modpost with musl libc") accidentally turned the unresolved symbol warnings into errors when vmlinux.o (for in-tree builds) or Module.symver (for external module builds) is missing. In those cases, unresolved symbols are expected, but the -w option is not set because 'missing-input' is referenced before set. Move $(missing-input) back to the original place. This should be fine for musl libc because vmlinux.o and -w are not added at the same time. With this change, -w may be passed twice, but it is not a big deal. Link: https://lore.kernel.org/all/b56a03b8-2a2a-f833-a5d2-cdc50a7ca2bb@cschramm.eu/ Fixes: 63ffe00d8c93 ("kbuild: Fix running modpost with musl libc") Reported-by: Christopher Schramm Signed-off-by: Masahiro Yamada Tested-by: Samuel Holland

kbuild: Fix running modpost with musl libc

2022-12-30T08:22:14+00:00

commit 3d57e1b7b1d4 ("kbuild: refactor the prerequisites of the modpost rule") moved 'vmlinux.o' inside modpost-args, possibly before some of the other options. However, getopt() in musl libc follows POSIX and stops looking for options upon reaching the first non-option argument. As a result, the '-T' option is misinterpreted as a positional argument, and the build fails: make -f ./scripts/Makefile.modpost scripts/mod/modpost -E -o Module.symvers vmlinux.o -T modules.order -T: No such file or directory make[1]: *** [scripts/Makefile.modpost:137: Module.symvers] Error 1 make: *** [Makefile:1960: modpost] Error 2 The fix is to move all options before 'vmlinux.o' in modpost-args. Fixes: 3d57e1b7b1d4 ("kbuild: refactor the prerequisites of the modpost rule") Signed-off-by: Samuel Holland Reviewed-by: Nathan Chancellor Signed-off-by: Masahiro Yamada

kbuild: refactor the prerequisites of the modpost rule

2022-12-14T06:42:40+00:00

The prerequisites of modpost are cluttered. The variables *-if-present and *-if-needed are unreadable. It is cleaner to append them into modpost-deps. Signed-off-by: Masahiro Yamada

kbuild: change module.order to list .o instead of .ko

2022-12-14T06:42:40+00:00

scripts/Makefile.build replaces the suffix .o with .ko, then scripts/Makefile.modpost calls the sed command to change .ko back to the original .o suffix. Instead of converting the suffixes back-and-forth, store the .o paths in modules.order, and replace it with .ko in 'make modules_install'. This avoids the unneeded sed command. Signed-off-by: Masahiro Yamada Reviewed-by: Luis Chamberlain

kbuild: add kbuild-file macro

2022-11-22T14:40:02+00:00

While building, installing, cleaning, Kbuild visits sub-directories and includes 'Kbuild' or 'Makefile' that exists there. Add 'kbuild-file' macro, and reuse it from scripts/Makefie.* Signed-off-by: Masahiro Yamada Reviewed-by: Nicolas Schier Reviewed-by: Alexander Lobakin Tested-by: Alexander Lobakin

kbuild: fix typo in modpost

2022-10-27T15:19:40+00:00

Commit f73edc8951b2 ("kbuild: unify two modpost invocations") introduced a typo (moudle.symvers-if-present) which results in the kernel's Module.symvers to not be included as a prerequisite for $(KBUILD_EXTMOD)/Module.symvers. Fix the typo to restore the intended functionality. Fixes: f73edc8951b2 ("kbuild: unify two modpost invocations") Signed-off-by: Will McVicker Signed-off-by: Masahiro Yamada