kernel/linux.git/Documentation/dev-tools/index.rst, branch v7.0.10

Merge tag 'kbuild-7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

2026-02-11T21:40:35+00:00

Pull Kbuild/Kconfig updates from Nathan Chancellor: "Kbuild: - Drop '*_probe' pattern from modpost section check allowlist, which hid legitimate warnings (Johan Hovold) - Disable -Wtype-limits altogether, instead of enabling at W=2 (Vincent Mailhol) - Improve UAPI testing to skip testing headers that require a libc when CONFIG_CC_CAN_LINK is not set, opening up testing of headers with no libc dependencies to more environments (Thomas Weißschuh) - Update gendwarfksyms documentation with required dependencies (Jihan LIN) - Reject invalid LLVM= values to avoid unintentionally falling back to system toolchain (Thomas Weißschuh) - Add a script to help run the kernel build process in a container for consistent environments and testing (Guillaume Tucker) - Simplify kallsyms by getting rid of the relative base (Ard Biesheuvel) - Performance and usability improvements to scripts/make_fit.py (Simon Glass) - Minor various clean ups and fixes Kconfig: - Move XPM icons to individual files, clearing up GTK deprecation warnings (Rostislav Krasny) - Support depends on FOO if BAR as syntactic sugar for depends on FOO || !BAR (Nicolas Pitre, Graham Roff) - Refactor merge_config.sh to use awk over shell/sed/grep, dramatically speeding up processing large number of config fragments (Anders Roxell, Mikko Rapeli)" * tag 'kbuild-7.0-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (39 commits) kbuild: remove dependency of run-command on config scripts/make_fit: Compress dtbs in parallel scripts/make_fit: Support a few more parallel compressors kbuild: Support a FIT_EXTRA_ARGS environment variable scripts/make_fit: Move dtb processing into a function scripts/make_fit: Support an initial ramdisk scripts/make_fit: Speed up operation rust: kconfig: Don't require RUST_IS_AVAILABLE for rustc-option MAINTAINERS: Add scripts/install.sh into Kbuild entry modpost: Amend ppc64 save/restfpr symnames for -Os build MIPS: tools: relocs: Ship a definition of R_MIPS_PC32 streamline_config.pl: remove superfluous exclamation mark kbuild: dummy-tools: Add python3 scripts: kconfig: merge_config.sh: warn on duplicate input files scripts: kconfig: merge_config.sh: use awk in checks too scripts: kconfig: merge_config.sh: refactor from shell/sed/grep to awk kallsyms: Get rid of kallsyms relative base mips: Add support for PC32 relocations in vmlinux Documentation: dev-tools: add container.rst page scripts: add tool to run containerized builds ...

Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2026-02-10T20:28:44+00:00

Pull locking updates from Ingo Molnar: "Lock debugging: - Implement compiler-driven static analysis locking context checking, using the upcoming Clang 22 compiler's context analysis features (Marco Elver) We removed Sparse context analysis support, because prior to removal even a defconfig kernel produced 1,700+ context tracking Sparse warnings, the overwhelming majority of which are false positives. On an allmodconfig kernel the number of false positive context tracking Sparse warnings grows to over 5,200... On the plus side of the balance actual locking bugs found by Sparse context analysis is also rather ... sparse: I found only 3 such commits in the last 3 years. So the rate of false positives and the maintenance overhead is rather high and there appears to be no active policy in place to achieve a zero-warnings baseline to move the annotations & fixers to developers who introduce new code. Clang context analysis is more complete and more aggressive in trying to find bugs, at least in principle. Plus it has a different model to enabling it: it's enabled subsystem by subsystem, which results in zero warnings on all relevant kernel builds (as far as our testing managed to cover it). Which allowed us to enable it by default, similar to other compiler warnings, with the expectation that there are no warnings going forward. This enforces a zero-warnings baseline on clang-22+ builds (Which are still limited in distribution, admittedly) Hopefully the Clang approach can lead to a more maintainable zero-warnings status quo and policy, with more and more subsystems and drivers enabling the feature. Context tracking can be enabled for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default disabled), but this will generate a lot of false positives. ( Having said that, Sparse support could still be added back, if anyone is interested - the removal patch is still relatively straightforward to revert at this stage. ) Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng) - Add support for Atomic and replace most Rust native AtomicBool usages with Atomic - Clean up LockClassKey and improve its documentation - Add missing Send and Sync trait implementation for SetOnce - Make ARef Unpin as it is supposed to be - Add __rust_helper to a few Rust helpers as a preparation for helper LTO - Inline various lock related functions to avoid additional function calls WW mutexes: - Extend ww_mutex tests and other test-ww_mutex updates (John Stultz) Misc fixes and cleanups: - rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd Bergmann) - locking/local_lock: Include more missing headers (Peter Zijlstra) - seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap) - rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir Duberstein)" * tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits) locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK rcu: Mark lockdep_assert_rcu_helper() __always_inline compiler-context-analysis: Remove __assume_ctx_lock from initializers tomoyo: Use scoped init guard crypto: Use scoped init guard kcov: Use scoped init guard compiler-context-analysis: Introduce scoped init guards cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers seqlock: fix scoped_seqlock_read kernel-doc tools: Update context analysis macros in compiler_types.h rust: sync: Replace `kernel::c_str!` with C-Strings rust: sync: Inline various lock related methods rust: helpers: Move #define __rust_helper out of atomic.c rust: wait: Add __rust_helper to helpers rust: time: Add __rust_helper to helpers rust: task: Add __rust_helper to helpers rust: sync: Add __rust_helper to helpers rust: refcount: Add __rust_helper to helpers rust: rcu: Add __rust_helper to helpers rust: processor: Add __rust_helper to helpers ...

Documentation: use a source-read extension for the index link boilerplate

2026-01-23T18:59:34+00:00

The root document usually has a special :ref:`genindex` link to the generated index. This is also the case for Documentation/index.rst. The other index.rst files deeper in the directory hierarchy usually don't. For SPHINXDIRS builds, the root document isn't Documentation/index.rst, but some other index.rst in the hierarchy. Currently they have a ".. only::" block to add the index link when doing SPHINXDIRS html builds. This is obviously very tedious and repetitive. The link is also added to all index.rst files in the hierarchy for SPHINXDIRS builds, not just the root document. Put the boilerplate in a sphinx-includes/subproject-index.rst file, and include it at the end of the root document for subproject builds in an ad-hoc source-read extension defined in conf.py. For now, keep having the boilerplate in translations, because this approach currently doesn't cover translated index link headers. Cc: Jonathan Corbet Cc: Mauro Carvalho Chehab Cc: Randy Dunlap Signed-off-by: Jani Nikula Tested-by: Mauro Carvalho Chehab Reviewed-by: Mauro Carvalho Chehab [jc: did s/doctree/kern_doc_dir/ ] Signed-off-by: Jonathan Corbet Message-ID: <20260123143149.2024303-1-jani.nikula@intel.com>

Documentation: dev-tools: add container.rst page

2026-01-22T22:33:27+00:00

Add a dev-tools/container.rst documentation page for the scripts/container tool. This covers the basic usage with additional information about environment variables and user IDs. It also includes a number of practical examples with a reference to the experimental kernel.org toolchain images. Update MAINTAINERS accordingly with a reference to the added file. Signed-off-by: Guillaume Tucker Reviewed-by: Onur Özkan Tested-by: Nicolas Schier Acked-by: Nicolas Schier Link: https://patch.msgid.link/af886533cc5cbdd6ef1d909793b79a1ad42c74ca.1769090419.git.gtucker@gtucker.io Signed-off-by: Nathan Chancellor

Documentation: Add documentation for Compiler-Based Context Analysis

2026-01-05T15:43:27+00:00

Adds documentation in Documentation/dev-tools/context-analysis.rst, and adds it to the index. Signed-off-by: Marco Elver Signed-off-by: Peter Zijlstra (Intel) Link: https://patch.msgid.link/20251219154418.3592607-5-elver@google.com

docs: Pull LKMM documentation into dev-tools book

2025-09-16T16:12:02+00:00

Currently, LKMM docs are not included in any of kernel documentation books. Commit e40573a43d16 ("docs: put atomic*.txt and memory-barriers.txt into the core-api book") covered plain-text docs under Documentation/ by using the "include::" directive along with the ":literal:" option. As LKMM docs are not under Documentation/, the same approach would not work due to the directive's restriction. As a matter of fact, kernel documentation has an extended directive by the name of "kernel-include::", which loosens such restriction and accepts any files under the kernel source tree. Rather than moving LKMM docs around, use the latter and pull them into the dev-tools book next to KCSAN. Signed-off-by: Akira Yokosawa Cc: Paul E. McKenney Acked-by: Paul E. McKenney Signed-off-by: Jonathan Corbet Message-ID: <7ce84a93-5cbc-420e-894a-06a0372c52ab@gmail.com>

Documentation: move dev-tools debugging files to process/debugging/

2024-12-17T20:46:53+00:00

Move gdb and kgdb debugging documentation to the dedicated debugging directory (Documentation/process/debugging/). Adjust the index.rst files to follow the file movement. Adjust files that refer to these moved files to follow the file movement. Update location of kgdb.rst in MAINTAINERS file. Add a link from dev-tools/index to process/debugging/index. Note: translations are not updated. Signed-off-by: Randy Dunlap Cc: Sebastian Fricke Cc: Jonathan Corbet Cc: workflows@vger.kernel.org Cc: Jason Wessel Cc: Daniel Thompson Cc: Douglas Anderson Cc: linux-debuggers@vger.kernel.org Cc: kgdb-bugreport@lists.sourceforge.net Cc: Doug Anderson Cc: Alex Shi Cc: Hu Haowen <2023002089@link.tyut.edu.cn> Cc: Andrew Morton Cc: Greg Kroah-Hartman Cc: linux-serial@vger.kernel.org Acked-by: Greg Kroah-Hartman Acked-by: Daniel Thompson Reviewed-by: Douglas Anderson Signed-off-by: Jonathan Corbet Link: https://lore.kernel.org/r/20241210000041.305477-1-rdunlap@infradead.org

kbuild: Add Propeller configuration for kernel build

2024-11-27T00:38:27+00:00

Add the build support for using Clang's Propeller optimizer. Like AutoFDO, Propeller uses hardware sampling to gather information about the frequency of execution of different code paths within a binary. This information is then used to guide the compiler's optimization decisions, resulting in a more efficient binary. The support requires a Clang compiler LLVM 19 or later, and the create_llvm_prof tool (https://github.com/google/autofdo/releases/tag/v0.30.1). This commit is limited to x86 platforms that support PMU features like LBR on Intel machines and AMD Zen3 BRS. Here is an example workflow for building an AutoFDO+Propeller optimized kernel: 1) Build the kernel on the host machine, with AutoFDO and Propeller build config CONFIG_AUTOFDO_CLANG=y CONFIG_PROPELLER_CLANG=y then $ make LLVM=1 CLANG_AUTOFDO_PROFILE= “” is the profile collected when doing a non-Propeller AutoFDO build. This step builds a kernel that has the same optimization level as AutoFDO, plus a metadata section that records basic block information. This kernel image runs as fast as an AutoFDO optimized kernel. 2) Install the kernel on test/production machines. 3) Run the load tests. The '-c' option in perf specifies the sample event period. We suggest using a suitable prime number, like 500009, for this purpose. For Intel platforms: $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c \ -o -- For AMD platforms: The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2 # To see if Zen3 support LBR: $ cat proc/cpuinfo | grep " brs" # To see if Zen4 support LBR: $ cat proc/cpuinfo | grep amd_lbr_v2 # If the result is yes, then collect the profile using: $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \ -N -b -c -o -- 4) (Optional) Download the raw perf file to the host machine. 5) Generate Propeller profile: $ create_llvm_prof --binary= --profile= \ --format=propeller --propeller_output_module_name \ --out=_cc_profile.txt \ --propeller_symorder=_ld_profile.txt “create_llvm_prof” is the profile conversion tool, and a prebuilt binary for linux can be found on https://github.com/google/autofdo/releases/tag/v0.30.1 (can also build from source). "" can be something like "/home/user/dir/any_string". This command generates a pair of Propeller profiles: "_cc_profile.txt" and "_ld_profile.txt". 6) Rebuild the kernel using the AutoFDO and Propeller profile files. CONFIG_AUTOFDO_CLANG=y CONFIG_PROPELLER_CLANG=y and $ make LLVM=1 CLANG_AUTOFDO_PROFILE= \ CLANG_PROPELLER_PROFILE_PREFIX= Co-developed-by: Han Shen Signed-off-by: Han Shen Signed-off-by: Rong Xu Suggested-by: Sriraman Tallam Suggested-by: Krzysztof Pszeniczny Suggested-by: Nick Desaulniers Suggested-by: Stephane Eranian Tested-by: Yonghong Song Tested-by: Nathan Chancellor Reviewed-by: Kees Cook Signed-off-by: Masahiro Yamada

kbuild: Add AutoFDO support for Clang build

2024-11-06T13:41:09+00:00

Add the build support for using Clang's AutoFDO. Building the kernel with AutoFDO does not reduce the optimization level from the compiler. AutoFDO uses hardware sampling to gather information about the frequency of execution of different code paths within a binary. This information is then used to guide the compiler's optimization decisions, resulting in a more efficient binary. Experiments showed that the kernel can improve up to 10% in latency. The support requires a Clang compiler after LLVM 17. This submission is limited to x86 platforms that support PMU features like LBR on Intel machines and AMD Zen3 BRS. Support for SPE on ARM 1, and BRBE on ARM 1 is part of planned future work. Here is an example workflow for AutoFDO kernel: 1) Build the kernel on the host machine with LLVM enabled, for example, $ make menuconfig LLVM=1 Turn on AutoFDO build config: CONFIG_AUTOFDO_CLANG=y With a configuration that has LLVM enabled, use the following command: scripts/config -e AUTOFDO_CLANG After getting the config, build with $ make LLVM=1 2) Install the kernel on the test machine. 3) Run the load tests. The '-c' option in perf specifies the sample event period. We suggest using a suitable prime number, like 500009, for this purpose. For Intel platforms: $ perf record -e BR_INST_RETIRED.NEAR_TAKEN:k -a -N -b -c \ -o -- For AMD platforms: The supported system are: Zen3 with BRS, or Zen4 with amd_lbr_v2 For Zen3: $ cat proc/cpuinfo | grep " brs" For Zen4: $ cat proc/cpuinfo | grep amd_lbr_v2 $ perf record --pfm-events RETIRED_TAKEN_BRANCH_INSTRUCTIONS:k -a \ -N -b -c -o -- 4) (Optional) Download the raw perf file to the host machine. 5) To generate an AutoFDO profile, two offline tools are available: create_llvm_prof and llvm_profgen. The create_llvm_prof tool is part of the AutoFDO project and can be found on GitHub (https://github.com/google/autofdo), version v0.30.1 or later. The llvm_profgen tool is included in the LLVM compiler itself. It's important to note that the version of llvm_profgen doesn't need to match the version of Clang. It needs to be the LLVM 19 release or later, or from the LLVM trunk. $ llvm-profgen --kernel --binary= --perfdata= \ -o or $ create_llvm_prof --binary= --profile= \ --format=extbinary --out= Note that multiple AutoFDO profile files can be merged into one via: $ llvm-profdata merge -o ... 6) Rebuild the kernel using the AutoFDO profile file with the same config as step 1, (Note CONFIG_AUTOFDO_CLANG needs to be enabled): $ make LLVM=1 CLANG_AUTOFDO_PROFILE= Co-developed-by: Han Shen Signed-off-by: Han Shen Signed-off-by: Rong Xu Suggested-by: Sriraman Tallam Suggested-by: Krzysztof Pszeniczny Suggested-by: Nick Desaulniers Suggested-by: Stephane Eranian Tested-by: Yonghong Song Tested-by: Yabin Cui Tested-by: Nathan Chancellor Reviewed-by: Kees Cook Tested-by: Peter Jung Signed-off-by: Masahiro Yamada

Merge tag 'docs-6.11' of git://git.lwn.net/linux

2024-07-18T22:54:16+00:00

Pull documentation updates from Jonathan Corbet: "Nothing hugely exciting happening in the documentation tree this time around, mostly more of the usual: - More Spanish, Italian, and Chinese translations - A new script, scripts/checktransupdate.py, can be used to see which commits have touched an (English) document since a given translation was last updated. - A couple of "best practices" suggestions (on Link: tags and off-list discussions) that were not entirely at consensus level, but I concluded they were close enough to accept. - Some nice cleanups removing documentation for kernel parameters that have not been recognized for ... a long time. ...along with the usual updates, typo fixes, and such" * tag 'docs-6.11' of git://git.lwn.net/linux: (57 commits) Documentation: Document user_events ioctl code docs/pinctrl: fix typo in mapping example docs: maintainer: discourage taking conversations off-list docs: driver-model: platform: update the definition of platform_driver docs/sp_SP: Add translation for scheduler/sched-design-CFS.rst writing_musb_glue_layer.rst: Fix broken URL zh_CN/admin-guide: one typo fix docs/zh_CN/virt: Update the translation of guest-halt-polling.rst Documentation: add reference from dynamic debug to loglevel kernel params Documentation: best practices for using Link trailers Documentation: fix links to mailing list services Documentation: exception-tables.rst: Fix the wrong steps referenced docs/zh_CN: add process/researcher-guidelines Chinese translation Documentation/tools/rv: fix document header docs/sp_SP: Add translation of process/maintainer-kvm-x86.rst docs/admin-guide/mm: correct typo 'quired' to 'queried' Add libps2 to the input section of driver-api Docs/mm/index: move allocation profiling document to unsorted documents chapter Docs/mm/index: rename 'Legacy Documentation' to 'Unsorted Documentation' Docs/mm/index: Remove 'Memory Management Guide' chapter marker ...