kernel/Documentation/kbuild, branch linux-5.10.y

Makefile.compiler: replace cc-ifversion with compiler-specific macros

2025-12-06T21:08:21Z

commit 88b61e3bff93f99712718db785b4aa0c1165f35c upstream. cc-ifversion is GCC specific. Replace it with compiler specific variants. Update the users of cc-ifversion to use these new macros. Link: https://github.com/ClangBuiltLinux/linux/issues/350 Link: https://lore.kernel.org/llvm/CAGG=3QWSAUakO42kubrCap8fp-gm1ERJJAYXTnP1iHk_wrH=BQ@mail.gmail.com/ Suggested-by: Bill Wendling Reviewed-by: Nathan Chancellor Signed-off-by: Nick Desaulniers Signed-off-by: Masahiro Yamada [nathan: Backport to 5.10 and eliminate instances of cc-ifversion that did not exist upstream when this change was original created] Signed-off-by: Nathan Chancellor Signed-off-by: Greg Kroah-Hartman

Documentation/Kbuild: Remove references to gcc-plugin.sh

2021-12-14T10:32:46Z

commit 1cabe74f148f7b99d9f08274a62467f96c870f07 upstream. gcc-plugin.sh has been removed in commit 1e860048c53e ("gcc-plugins: simplify GCC plugin-dev capability test"). Signed-off-by: Robert Karszniewicz Reviewed-by: Kees Cook Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

doc: gcc-plugins: update gcc-plugins.rst

2021-12-14T10:32:46Z

commit 9b6164342e981d751e69f5a165dd596ffcdfd6fe upstream. This document was written a long time ago. Update it. [1] Drop the version information The range of the supported GCC versions are always changing. The current minimal GCC version is 4.9, and commit 1e860048c53e ("gcc-plugins: simplify GCC plugin-dev capability test") removed the old code accordingly. We do not need to mention specific version ranges like "all gcc versions from 4.5 to 6.0" since we forget to update the documentation when we raise the minimal compiler version. [2] Drop the C compiler statements Since commit 77342a02ff6e ("gcc-plugins: drop support for GCC <= 4.7") the GCC plugin infrastructure only supports g++. [3] Drop supported architectures As of v5.11-rc4, the infrastructure supports more architectures; arm, arm64, mips, powerpc, riscv, s390, um, and x86. (just grep "select HAVE_GCC_PLUGINS") Again, we miss to update this document when a new architecture is supported. Let's just say "only some architectures". [4] Update the apt-get example We are now discussing to bump the minimal version to GCC 5. The GCC 4.9 support will be removed sooner or later. Change the package example to gcc-10-plugin-dev while we are here. [5] Update the build target Since commit ce2fd53a10c7 ("kbuild: descend into scripts/gcc-plugins/ via scripts/Makefile"), "make gcc-plugins" is not supported. "make scripts" builds all the enabled plugins, including some other tools. [6] Update the steps for adding a new plugin At first, all CONFIG options for GCC plugins were located in arch/Kconfig. After commit 45332b1bdfdc ("gcc-plugins: split out Kconfig entries to scripts/gcc-plugins/Kconfig"), scripts/gcc-plugins/Kconfig became the central place to collect plugin CONFIG options. In my understanding, this requirement no longer exists because commit 9f671e58159a ("security: Create "kernel hardening" config area") moved some of plugin CONFIG options to another file. Find an appropriate place to add the new CONFIG. The sub-directory support was never used by anyone, and removed by commit c17d6179ad5a ("gcc-plugins: remove unused GCC_PLUGIN_SUBDIR"). Remove the useless $(src)/ prefix. Signed-off-by: Masahiro Yamada Signed-off-by: Greg Kroah-Hartman

kbuild: remove unused OBJSIZE

2020-11-02T02:31:00Z

The "size" tool has been solely used by s390 to enforce .bss section usage restrictions in early startup code. Since commit 980d5f9ab36b ("s390/boot: enable .bss section for compressed kernel") and commit 2e83e0eb85ca ("s390: clean .bss before running uncompressed kernel") these restrictions have been lifted for the decompressor and uncompressed kernel and the size tool is now unused. Signed-off-by: Vasily Gorbik Reviewed-by: Nathan Chancellor Signed-off-by: Masahiro Yamada

kbuild: doc: describe proper script invocation

2020-10-14T01:38:26Z

During an investigation to fix up the execute bits of scripts in the kernel repository, Andrew Morton and Kees Cook pointed out that the execute bit should not matter, and that build scripts cannot rely on that. Kees could not point to any documentation, though. Masahiro Yamada explained the convention of setting execute bits to make it easier for manual script invocation. Provide some basic documentation how the build shall invoke scripts, such that the execute bits do not matter, and acknowledge that execute bits are useful nonetheless. This serves as reference for further clean-up patches in the future. Suggested-by: Andrew Morton Suggested-by: Kees Cook Signed-off-by: Lukas Bulwahn Signed-off-by: Andrew Morton Cc: Masahiro Yamada Cc: Michal Marek Cc: Jonathan Corbet Cc: Ujjwal Kumar Cc: Lukas Bulwahn Link: https://lore.kernel.org/lkml/20200830174409.c24c3f67addcce0cea9a9d4c@linux-foundation.org/ Link: https://lore.kernel.org/lkml/202008271102.FEB906C88@keescook/ Link: https://lore.kernel.org/linux-kbuild/CAK7LNAQdrvMkDA6ApDJCGr+5db8SiPo=G+p8EiOvnnGvEN80gA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20201001075723.24246-1-lukas.bulwahn@gmail.com Signed-off-by: Linus Torvalds

Merge tag 'docs-5.10' of git://git.lwn.net/linux

2020-10-12T23:21:29Z

Pull documentation updates from Jonathan Corbet: "As hoped, things calmed down for docs this cycle; fewer changes and almost no conflicts at all. This includes: - A reworked and expanded user-mode Linux document - Some simplifications and improvements for submitting-patches.rst - An emergency fix for (some) problems with Sphinx 3.x - Some welcome automarkup improvements to automatically generate cross-references to struct definitions and other documents - The usual collection of translation updates, typo fixes, etc" * tag 'docs-5.10' of git://git.lwn.net/linux: (81 commits) gpiolib: Update indentation in driver.rst for code excerpts Documentation/admin-guide: tainted-kernels: Fix typo occured Documentation: better locations for sysfs-pci, sysfs-tagging docs: programming-languages: refresh blurb on clang support Documentation: kvm: fix a typo Documentation: Chinese translation of Documentation/arm64/amu.rst doc: zh_CN: index files in arm64 subdirectory mailmap: add entry for doc: seq_file: clarify role of *pos in ->next() docs: trace: ring-buffer-design.rst: use the new SPDX tag Documentation: kernel-parameters: clarify "module." parameters Fix references to nommu-mmap.rst docs: rewrite admin-guide/sysctl/abi.rst docs: fb: Remove vesafb scrollback boot option docs: fb: Remove sstfb scrollback boot option docs: fb: Remove matroxfb scrollback boot option docs: fb: Remove framebuffer scrollback boot option docs: replace the old User Mode Linux HowTo with a new one Documentation/admin-guide: blockdev/ramdisk: remove use of "rdev" Documentation/admin-guide: README & svga: remove use of "rdev" ...

Documentation/llvm: Fix clang target examples

2020-09-26T04:54:08Z

clang --target= is how we can specify a particular toolchain triple to be use, fix the two occurences in the documentation. Fixes: fcf1b6a35c16 ("Documentation/llvm: add documentation on building w/ Clang/LLVM") Signed-off-by: Florian Fainelli Reviewed-by: Nick Desaulniers Reviewed-by: Nathan Chancellor Signed-off-by: Masahiro Yamada

kbuild: Documentation: clean up makefiles.rst

2020-09-03T03:21:22Z

This is a general cleanup of kbuild/makefiles.rst: * Use "Chapter" for major heading references and use "section" for the next-level heading references, for consistency. * Section 3.8 was deleted long ago. * Drop the ending ':' in section names in the contents list. * Correct some section numbering references. * Correct verb agreement typo. * Fix run-on sentence punctuation. Signed-off-by: Randy Dunlap Signed-off-by: Masahiro Yamada

Documentation: add minimum clang/llvm version

2020-08-31T22:30:20Z

Based on a vote at the LLVM BoF at Plumbers 2020, we decided to start small, supporting just one formal upstream release of LLVM for now. We can probably widen the support window of supported versions over time. Also, note that LLVM's release process is different than GCC's. GCC tends to have 1 major release per year while releasing minor updates to the past 3 major versions. LLVM tends to support one major release and one minor release every six months. Signed-off-by: Nick Desaulniers Tested-by: Gustavo A. R. Silva Tested-by: Nathan Chancellor Reviewed-by: Kees Cook Reviewed-by: Nathan Chancellor Reviewed-by: Masahiro Yamada Acked-by: Will Deacon Link: https://lore.kernel.org/r/20200826191555.3350406-1-ndesaulniers@google.com Signed-off-by: Jonathan Corbet

Documentation/llvm: Improve formatting of commands, variables, and arguments

2020-08-31T10:48:20Z

While reviewing a separate patch, I noticed that the formatting of the commands, variables, and arguments was not in a monospaced font like the rest of the Kbuild documentation (see kbuild/kconfig.rst for an example). This is due to a lack of "::" before indented command blocks and single backticks instead of double backticks for inline formatting. Add those so that the document looks nicer in an HTML format, while not ruining the look in plain text. As a result of this, we can remove the escaped backslashes in the last code block and move them to single backslashes. Signed-off-by: Nathan Chancellor Reviewed-by: Nick Desaulniers Signed-off-by: Masahiro Yamada