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2023-07-01Merge tag 'kbuild-v6.5' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild Pull Kbuild updates from Masahiro Yamada: - Remove the deprecated rule to build *.dtbo from *.dts - Refactor section mismatch detection in modpost - Fix bogus ARM section mismatch detections - Fix error of 'make gtags' with O= option - Add Clang's target triple to KBUILD_CPPFLAGS to fix a build error with the latest LLVM version - Rebuild the built-in initrd when KBUILD_BUILD_TIMESTAMP is changed - Ignore more compiler-generated symbols for kallsyms - Fix 'make local*config' to handle the ${CONFIG_FOO} form in Makefiles - Enable more kernel-doc warnings with W=2 - Refactor <linux/export.h> by generating KSYMTAB data by modpost - Deprecate <asm/export.h> and <asm-generic/export.h> - Remove the EXPORT_DATA_SYMBOL macro - Move the check for static EXPORT_SYMBOL back to modpost, which makes the build faster - Re-implement CONFIG_TRIM_UNUSED_KSYMS with one-pass algorithm - Warn missing MODULE_DESCRIPTION when building modules with W=1 - Make 'make clean' robust against too long argument error - Exclude more objects from GCOV to fix CFI failures with GCOV - Allow 'make modules_install' to install modules.builtin and modules.builtin.modinfo even when CONFIG_MODULES is disabled - Include modules.builtin and modules.builtin.modinfo in the linux-image Debian package even when CONFIG_MODULES is disabled - Revive "Entering directory" logging for the latest Make version * tag 'kbuild-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (72 commits) modpost: define more R_ARM_* for old distributions kbuild: revive "Entering directory" for Make >= 4.4.1 kbuild: set correct abs_srctree and abs_objtree for package builds scripts/mksysmap: Ignore prefixed KCFI symbols kbuild: deb-pkg: remove the CONFIG_MODULES check in buildeb kbuild: builddeb: always make modules_install, to install modules.builtin* modpost: continue even with unknown relocation type modpost: factor out Elf_Sym pointer calculation to section_rel() modpost: factor out inst location calculation to section_rel() kbuild: Disable GCOV for *.mod.o kbuild: Fix CFI failures with GCOV kbuild: make clean rule robust against too long argument error script: modpost: emit a warning when the description is missing kbuild: make modules_install copy modules.builtin(.modinfo) linux/export.h: rename 'sec' argument to 'license' modpost: show offset from symbol for section mismatch warnings modpost: merge two similar section mismatch warnings kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion modpost: use null string instead of NULL pointer for default namespace modpost: squash sym_update_namespace() into sym_add_exported() ...
2023-06-29Makefile: Add loongarch target flag for Clang compilationWANG Xuerui
The LoongArch kernel is 64-bit and built with the soft-float ABI, hence the loongarch64-linux-gnusf target. (The "libc" part can affect the codegen of libcalls: other arches do not use a bare-metal target, and currently the only fully supported libc on LoongArch is glibc anyway.) See: https://lore.kernel.org/loongarch/CAKwvOdnimxv8oJ4mVY74zqtt1x7KTMrWvn2_T9x22SFDbU6rHQ@mail.gmail.com/ Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: WANG Xuerui <git@xen0n.name> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
2023-06-05kbuild: add $(CLANG_FLAGS) to KBUILD_CPPFLAGSMasahiro Yamada
When preprocessing arch/*/kernel/vmlinux.lds.S, the target triple is not passed to $(CPP) because we add it only to KBUILD_{C,A}FLAGS. As a result, the linker script is preprocessed with predefined macros for the build host instead of the target. Assuming you use an x86 build machine, compare the following: $ clang -dM -E -x c /dev/null $ clang -dM -E -x c /dev/null -target aarch64-linux-gnu There is no actual problem presumably because our linker scripts do not rely on such predefined macros, but it is better to define correct ones. Move $(CLANG_FLAGS) to KBUILD_CPPFLAGS, so that all *.c, *.S, *.lds.S will be processed with the proper target triple. [Note] After the patch submission, we got an actual problem that needs this commit. (CBL issue 1859) Link: https://github.com/ClangBuiltLinux/linux/issues/1859 Reported-by: Tom Rini <trini@konsulko.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Tested-by: Nathan Chancellor <nathan@kernel.org>
2023-04-17kbuild: clang: do not use CROSS_COMPILE for target tripleMasahiro Yamada
The target triple is overridden by the user-supplied CROSS_COMPILE, but I do not see a good reason to support it. Users can use a new architecture without adding CLANG_TARGET_FLAGS_*, but that would be a rare case. Use the hard-coded and deterministic target triple all the time. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2023-01-26kbuild: Turn a couple more of clang's unused option warnings into errorsNathan Chancellor
Currently, these warnings are hidden with -Qunused-arguments in KBUILD_CPPFLAGS. Once that option is removed, these warnings should be turned into hard errors to make unconditionally added but unsupported flags for the current compilation mode or target obvious due to a failed build; otherwise, the warnings might just be ignored if the build log is not checked. Link: https://github.com/ClangBuiltLinux/linux/issues/1587 Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Linux Kernel Functional Testing <lkft@linaro.org> Tested-by: Anders Roxell <anders.roxell@linaro.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-03-21um: Allow builds with ClangKees Cook
Add SUBARCH target for Clang+um (which must go last, not alphabetically, so the other SUBARCHes are assigned). Remove open-coded "DEFINE" macro, instead using linux/kbuild.h's version which was updated to use Clang-friendly assembly in commit cf0c3e68aa81 ("kbuild: fix asm-offset generation to work with clang"). Redefine "DEFINE_LONGS" in terms of "COMMENT" and "DEFINE" so that the intended coment actually has useful content. Add a missed "break" to avoid implicit fall-through warnings. This lets me run KUnit tests with Clang: $ ./tools/testing/kunit/kunit.py run --make_options LLVM=1 ... Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nathan Chancellor <nathan@kernel.org> Cc: David Gow <davidgow@google.com> Cc: linux-um@lists.infradead.org Cc: linux-kbuild@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Cc: kunit-dev@googlegroups.com Cc: llvm@lists.linux.dev Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/lkml/Yg2YubZxvYvx7%2Fnm@dev-arch.archlinux-ax161/ Tested-by: David Gow <davidgow@google.com> Link: https://lore.kernel.org/lkml/CABVgOSk=oFxsbSbQE-v65VwR2+mXeGXDDjzq8t7FShwjJ3+kUg@mail.gmail.com/ Signed-off-by: Kees Cook <keescook@chromium.org> --- v1: https://lore.kernel.org/lkml/20220217002843.2312603-1-keescook@chromium.org v2: https://lore.kernel.org/lkml/20220224055831.1854786-1-keescook@chromium.org v3: - use kbuild.h to avoid duplication (Masahiro) - fix intended comments (Masahiro) - use SUBARCH (Nathan)
2021-09-19kbuild: Add -Werror=ignored-optimization-argument to CLANG_FLAGSNathan Chancellor
Similar to commit 589834b3a009 ("kbuild: Add -Werror=unknown-warning-option to CLANG_FLAGS"). Clang ignores certain GCC flags that it has not implemented, only emitting a warning: $ echo | clang -fsyntax-only -falign-jumps -x c - clang-14: warning: optimization flag '-falign-jumps' is not supported [-Wignored-optimization-argument] When one of these flags gets added to KBUILD_CFLAGS unconditionally, all subsequent cc-{disable-warning,option} calls fail because -Werror was added to these invocations to turn the above warning and the equivalent -W flag warning into errors. To catch the presence of these flags earlier, turn -Wignored-optimization-argument into an error so that the flags can either be implemented or ignored via cc-option and there are no more weird errors. Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-09-03kbuild: Switch to 'f' variants of integrated assembler flagNathan Chancellor
It has been brought up a few times in various code reviews that clang 3.5 introduced -f{,no-}integrated-as as the preferred way to enable and disable the integrated assembler, mentioning that -{no-,}integrated-as are now considered legacy flags. Switch the kernel over to using those variants in case there is ever a time where clang decides to remove the non-'f' variants of the flag. Also, fix a typo in a comment ("intergrated" -> "integrated"). Link: https://releases.llvm.org/3.5.0/tools/clang/docs/ReleaseNotes.html#new-compiler-flags Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10scripts/Makefile.clang: default to LLVM_IAS=1Nick Desaulniers
LLVM_IAS=1 controls enabling clang's integrated assembler via -integrated-as. This was an explicit opt in until we could enable assembler support in Clang for more architecures. Now we have support and CI coverage of LLVM_IAS=1 for all architecures except a few more bugs affecting s390 and powerpc. This commit flips the default from opt in via LLVM_IAS=1 to opt out via LLVM_IAS=0. CI systems or developers that were previously doing builds with CC=clang or LLVM=1 without explicitly setting LLVM_IAS must now explicitly opt out via LLVM_IAS=0, otherwise they will be implicitly opted-in. This finally shortens the command line invocation when cross compiling with LLVM to simply: $ make ARCH=arm64 LLVM=1 Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10Makefile: infer --target from ARCH for CC=clangNick Desaulniers
We get constant feedback that the command line invocation of make is too long when compiling with LLVM. CROSS_COMPILE is helpful when a toolchain has a prefix of the target triple, or is an absolute path outside of $PATH. Since a Clang binary is generally multi-targeted, we can infer a given target from SRCARCH/ARCH. If CROSS_COMPILE is not set, simply set --target= for CLANG_FLAGS, KBUILD_CFLAGS, and KBUILD_AFLAGS based on $SRCARCH. Previously, we'd cross compile via: $ ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- make LLVM=1 LLVM_IAS=1 Now: $ ARCH=arm64 make LLVM=1 LLVM_IAS=1 For native builds (not involving cross compilation) we now explicitly specify a target triple rather than rely on the implicit host triple. Link: https://github.com/ClangBuiltLinux/linux/issues/1399 Suggested-by: Arnd Bergmann <arnd@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Suggested-by: Nathan Chancellor <nathan@kernel.org> Acked-by: Arnd Bergmann <arnd@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Acked-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-10Makefile: move initial clang flag handling into scripts/Makefile.clangNick Desaulniers
With some of the changes we'd like to make to CROSS_COMPILE, the initial block of clang flag handling which controls things like the target triple, whether or not to use the integrated assembler and how to find GAS, and erroring on unknown warnings is becoming unwieldy. Move it into its own file under scripts/. Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>