lwn.git/scripts/Makefile.extrawarn, branch docs-6.9

Merge tag 'kbuild-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2024-01-19T01:57:07+00:00

Pull Kbuild updates from Masahiro Yamada: - Make Kconfig parse the input .config more precisely - Support W=c and W=e options for Kconfig - Set Kconfig int/hex symbols to zero if the 'default' property is missing - Add .editorconfig - Add scripts/git.orderFile - Add a script to detect backward-incompatible changes in UAPI headers - Resolve the symlink passed to O= option properly - Use the user-supplied mtime for all files in the builtin initramfs, which provides better reproducible builds - Fix the direct execution of debian/rules for Debian package builds - Use build ID instead of the .gnu_debuglink section for the Debian dbg package * tag 'kbuild-v6.8' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (53 commits) kbuild: deb-pkg: use debian/ for tmpdir kbuild: deb-pkg: move 'make headers' to build-arch kbuild: deb-pkg: do not search for 'scripts' directory under arch/ kbuild: deb-pkg: use build ID instead of debug link for dbg package kbuild: deb-pkg: use more debhelper commands in builddeb kbuild: deb-pkg: remove unneeded '-f $srctree/Makefile' in debian/rules kbuild: deb-pkg: allow to run debian/rules from output directory kbuild: deb-pkg: set DEB_* variables if debian/rules is directly executed kbuild: deb-pkg: squash scripts/package/deb-build-option to debian/rules kbuild: deb-pkg: factor out common Make options in debian/rules kbuild: deb-pkg: hard-code Build-Depends kbuild: deb-pkg: split debian/copyright from the mkdebian script gen_init_cpio: Apply mtime supplied by user to all file types kbuild: resolve symlinks for O= properly docs: dev-tools: Add UAPI checker documentation check-uapi: Introduce check-uapi.sh scripts: Introduce a default git.orderFile kconfig: WERROR unmet symbol dependency Add .editorconfig file for basic formatting kconfig: Use KCONFIG_CONFIG instead of .config ...

Makefile.extrawarn: turn on missing-prototypes globally

2023-12-20T23:02:57+00:00

Over the years we went from > 1000 of warnings to under 100 earlier this year, and I sent patches to address all the ones that I saw with compile testing randcom configs on arm64, arm and x86 kernels. This is a really useful warning, as it catches real bugs when there are mismatched prototypes. In particular with kernel control flow integrity enabled, those are no longer allowed. I have done extensive testing to ensure that there are no new build errors or warnings on any configuration of x86, arm and arm64 builds. I also made sure that at least both the normal defconfig and an allmodconfig build is clean for arc, csky, loongarch, m68k, microblaze, openrisc, parisc, powerpc, riscv, s390, and xtensa, with the respective maintainers doing most of the patches. At this point, there are five architectures with a number of known regressions: alpha, nios2, mips, sh and sparc. In the previous version of this patch, I had turned off the missing prototype warnings for the 15 architectures that still had issues, but since there are only five left, I think we can leave the rest to the maintainers (Cc'd here) as well. Link: https://lkml.kernel.org/r/20231123110506.707903-7-arnd@kernel.org Link: https://lore.kernel.org/lkml/20230810141947.1236730-1-arnd@kernel.org/ Signed-off-by: Arnd Bergmann Reviewed-by: Kees Cook Acked-by: Palmer Dabbelt # RISC-V Cc: Richard Henderson Cc: Ivan Kokshaysky Cc: Matt Turner Cc: Dinh Nguyen Cc: Thomas Bogendoerfer Cc: Yoshinori Sato Cc: Rich Felker Cc: John Paul Adrian Glaubitz Cc: "David S. Miller" Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Masahiro Yamada Cc: Michael Ellerman Cc: Nathan Chancellor Cc: Nicolas Schier Cc: Peter Zijlstra Cc: Richard Weinberger Cc: Stephen Rothwell Cc: Tudor Ambarus Cc: Zhihao Cheng Signed-off-by: Andrew Morton

kbuild: support W=c and W=e shorthands for Kconfig

2023-12-03T09:50:48+00:00

KCONFIG_WARN_UNKNOWN_SYMBOLS=1 and KCONFIG_WERROR=1 are descriptive and suitable in scripting, but typing them from the command line can be tedious. Associate them with KBUILD_EXTRA_WARN (and the W= shorthand). Support a new letter 'c' to enable extra checks in Kconfig. You can still manage compiler warnings (W=1) and Kconfig warnings (W=c) independently. Reuse the letter 'e' to turn Kconfig warnings into errors. As usual, you can combine multiple letters in KCONFIG_EXTRA_WARN. $ KCONFIG_WARN_UNKNOWN_SYMBOLS=1 KCONFIG_WERROR=1 make defconfig can be shortened to: $ KBUILD_EXTRA_WARN=ce make defconfig or, even shorter: $ make W=ce defconfig Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor

extrawarn: move -Wrestrict into W=1 warnings

2023-08-20T05:16:59+00:00

There are few of these, so enable them whenever W=1 is enabled. Signed-off-by: Arnd Bergmann Signed-off-by: Masahiro Yamada

extrawarn: enable format and stringop overflow warnings in W=1

2023-08-20T05:16:59+00:00

The stringop and format warnings got disabled globally when they were newly introduced in commit bd664f6b3e376 ("disable new gcc-7.1.1 warnings for now"), 217c3e0196758 ("disable stringop truncation warnings for now") and 5a76021c2eff7 ("gcc-10: disable 'stringop-overflow' warning for now"). In all cases, the sentiment at the time was that the warnings are useful, and we actually addressed a number of real bugs based on them, but we never managed to eliminate them all because even the build bots using W=1 builds only see the -Wstringop-truncation warnings that are enabled at that level. Move these into the W=1 section to give them a larger build coverage and actually eliminate them over time. Signed-off-by: Arnd Bergmann Signed-off-by: Masahiro Yamada

kbuild: avoid duplicate warning options

2023-08-20T05:16:57+00:00

Some warning options are disabled at one place and then conditionally re-enabled later in scripts/Makefile.extrawarn. For consistency, rework this file so each of those warnings only gets etiher enabled or disabled based on the W= flags but not both. Signed-off-by: Arnd Bergmann Signed-off-by: Masahiro Yamada

kbuild: consolidate warning flags in scripts/Makefile.extrawarn

2023-08-20T05:16:54+00:00

Warning options are enabled and disabled in inconsistent ways and inconsistent locations. Start rearranging those by moving all options into Makefile.extrawarn. This should not change any behavior, but makes sure we can group them in a way that ensures that each warning that got temporarily disabled is turned back on at an appropriate W=1 level later on. Signed-off-by: Arnd Bergmann Signed-off-by: Masahiro Yamada

kbuild: add -Wundef to KBUILD_CPPFLAGS for W=1 builds

2022-12-11T08:28:32+00:00

The use of an undefined macro in an #if directive is warned, but only in *.c files. No warning from other files such as *.S, *.lds.S. Since -Wundef is a preprocessor-related warning, it should be added to KBUILD_CPPFLAGS instead of KBUILD_CFLAGS. My previous attempt [1] uncovered several issues. I could not finish fixing them all. This commit adds -Wundef to KBUILD_CPPFLAGS for W=1 builds in order to block new breakages. (The kbuild test robot tests with W=1) We can fix the warnings one by one. After fixing all of them, we can make it default in the top Makefile, and remove -Wundef from KBUILD_CFLAGS. [1]: https://lore.kernel.org/all/20221012180118.331005-2-masahiroy@kernel.org/ Signed-off-by: Masahiro Yamada Reviewed-by: Nathan Chancellor Reviewed-by: Nick Desaulniers

Merge tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

2022-10-10T19:00:45+00:00

Pull Kbuild updates from Masahiro Yamada: - Remove potentially incomplete targets when Kbuid is interrupted by SIGINT etc in case GNU Make may miss to do that when stderr is piped to another program. - Rewrite the single target build so it works more correctly. - Fix rpm-pkg builds with V=1. - List top-level subdirectories in ./Kbuild. - Ignore auto-generated __kstrtab_* and __kstrtabns_* symbols in kallsyms. - Avoid two different modules in lib/zstd/ having shared code, which potentially causes building the common code as build-in and modular back-and-forth. - Unify two modpost invocations to optimize the build process. - Remove head-y syntax in favor of linker scripts for placing particular sections in the head of vmlinux. - Bump the minimal GNU Make version to 3.82. - Clean up misc Makefiles and scripts. * tag 'kbuild-v6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (41 commits) docs: bump minimal GNU Make version to 3.82 ia64: simplify esi object addition in Makefile Revert "kbuild: Check if linker supports the -X option" kbuild: rebuild .vmlinux.export.o when its prerequisite is updated kbuild: move modules.builtin(.modinfo) rules to Makefile.vmlinux_o zstd: Fixing mixed module-builtin objects kallsyms: ignore __kstrtab_* and __kstrtabns_* symbols kallsyms: take the input file instead of reading stdin kallsyms: drop duplicated ignore patterns from kallsyms.c kbuild: reuse mksysmap output for kallsyms mksysmap: update comment about __crc_* kbuild: remove head-y syntax kbuild: use obj-y instead extra-y for objects placed at the head kbuild: hide error checker logs for V=1 builds kbuild: re-run modpost when it is updated kbuild: unify two modpost invocations kbuild: move vmlinux.o rule to the top Makefile kbuild: move .vmlinux.objs rule to Makefile.modpost kbuild: list sub-directories in ./Kbuild Makefile.compiler: replace cc-ifversion with compiler-specific macros ...

Merge tag 'hardening-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2022-10-04T00:24:22+00:00

Pull kernel hardening updates from Kees Cook: "Most of the collected changes here are fixes across the tree for various hardening features (details noted below). The most notable new feature here is the addition of the memcpy() overflow warning (under CONFIG_FORTIFY_SOURCE), which is the next step on the path to killing the common class of "trivially detectable" buffer overflow conditions (i.e. on arrays with sizes known at compile time) that have resulted in many exploitable vulnerabilities over the years (e.g. BleedingTooth). This feature is expected to still have some undiscovered false positives. It's been in -next for a full development cycle and all the reported false positives have been fixed in their respective trees. All the known-bad code patterns we could find with Coccinelle are also either fixed in their respective trees or in flight. The commit message in commit 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()") for the feature has extensive details, but I'll repeat here that this is a warning _only_, and is not intended to actually block overflows (yet). The many patches fixing array sizes and struct members have been landing for several years now, and we're finally able to turn this on to find any remaining stragglers. Summary: Various fixes across several hardening areas: - loadpin: Fix verity target enforcement (Matthias Kaehlcke). - zero-call-used-regs: Add missing clobbers in paravirt (Bill Wendling). - CFI: clean up sparc function pointer type mismatches (Bart Van Assche). - Clang: Adjust compiler flag detection for various Clang changes (Sami Tolvanen, Kees Cook). - fortify: Fix warnings in arch-specific code in sh, ARM, and xen. Improvements to existing features: - testing: improve overflow KUnit test, introduce fortify KUnit test, add more coverage to LKDTM tests (Bart Van Assche, Kees Cook). - overflow: Relax overflow type checking for wider utility. New features: - string: Introduce strtomem() and strtomem_pad() to fill a gap in strncpy() replacement needs. - um: Enable FORTIFY_SOURCE support. - fortify: Enable run-time struct member memcpy() overflow warning" * tag 'hardening-v6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (27 commits) Makefile.extrawarn: Move -Wcast-function-type-strict to W=1 hardening: Remove Clang's enable flag for -ftrivial-auto-var-init=zero sparc: Unbreak the build x86/paravirt: add extra clobbers with ZERO_CALL_USED_REGS enabled x86/paravirt: clean up typos and grammaros fortify: Convert to struct vs member helpers fortify: Explicitly check bounds are compile-time constants x86/entry: Work around Clang __bdos() bug ARM: decompressor: Include .data.rel.ro.local fortify: Adjust KUnit test for modular build sh: machvec: Use char[] for section boundaries kunit/memcpy: Avoid pathological compile-time string size lib: Improve the is_signed_type() kunit test LoadPin: Require file with verity root digests to have a header dm: verity-loadpin: Only trust verity targets with enforcement LoadPin: Fix Kconfig doc about format of file with verity digests um: Enable FORTIFY_SOURCE lkdtm: Update tests for memcpy() run-time warnings fortify: Add run-time WARN for cross-field memcpy() fortify: Use SIZE_MAX instead of (size_t)-1 ...