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Kees Cook b3a7bb71bf KUnit: Introduce ffs()-family tests
Add KUnit tests for ffs()-family bit scanning functions: ffs(), __ffs(),
fls(), __fls(), fls64(), __ffs64(), and ffz(). The tests validate
mathematical relationships (e.g. ffs(x) == __ffs(x) + 1), and test zero
values, power-of-2 patterns, maximum values, and sparse bit patterns.

Build and run tested with everything I could reach with KUnit:

$ ./tools/testing/kunit/kunit.py run --arch=x86_64 ffs
$ ./tools/testing/kunit/kunit.py run --arch=i386 ffs
$ ./tools/testing/kunit/kunit.py run --arch=arm64 --make_options "CROSS_COMPILE=aarch64-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=arm --make_options "CROSS_COMPILE=arm-linux-gnueabihf-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=powerpc ffs
$ ./tools/testing/kunit/kunit.py run --arch=powerpc32 ffs
$ ./tools/testing/kunit/kunit.py run --arch=powerpcle ffs
$ ./tools/testing/kunit/kunit.py run --arch=riscv --make_options "CROSS_COMPILE=riscv64-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=riscv32 --make_options "CROSS_COMPILE=riscv64-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=s390 --make_options "CROSS_COMPILE=s390x-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=m68k ffs
$ ./tools/testing/kunit/kunit.py run --arch=loongarch ffs
$ ./tools/testing/kunit/kunit.py run --arch=mips --make_options "CROSS_COMPILE=mipsel-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=sparc --make_options "CROSS_COMPILE=sparc64-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=sparc64 --make_options "CROSS_COMPILE=sparc64-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=alpha --make_options "CROSS_COMPILE=alpha-linux-gnu-" ffs
$ ./tools/testing/kunit/kunit.py run --arch=sh --make_options "CROSS_COMPILE=sh4-linux-gnu-" ffs

Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250804164417.1612371-1-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
2025-09-08 14:58:50 -07:00
Documentation - Remove a transitional asm/cpuid.h header which was added only as 2025-08-17 06:53:15 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
arch - Remove a transitional asm/cpuid.h header which was added only as 2025-08-17 06:53:15 -07:00
block block: restore default wbt enablement 2025-08-13 05:33:48 -06:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
drivers PCI: Test for bit underflow in pcie_set_readrq() 2025-09-08 14:58:20 -07:00
fs xfs: Fixes for 6.17-rc2 2025-08-15 12:50:12 -07:00
include - Make sure sanity checks down in the mutex lock path happen on the correct 2025-08-17 05:57:47 -07:00
init Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
io_uring io_uring/io-wq: add check free worker before create new worker 2025-08-13 06:31:10 -06:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel - Make sure sanity checks down in the mutex lock path happen on the correct 2025-08-17 05:57:47 -07:00
lib KUnit: Introduce ffs()-family tests 2025-09-08 14:58:50 -07:00
mm mm/mremap: avoid expensive folio lookup on mremap folio pte batch 2025-08-11 23:00:59 -07:00
net Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
rust rust: kbuild: clean output before running `rustdoc` 2025-08-12 21:10:50 +02:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: hda/tas2781: Normalize the volume kcontrol name 2025-08-14 11:17:12 +02:00
tools Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about `clippy::disallowed_macros` configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING
CREDITS Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Including fixes from Netfilter and IPsec. 2025-08-14 07:14:30 -07:00
Makefile Linux 6.17-rc2 2025-08-17 15:22:10 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.