Merge tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

Pull Kbuild / Kconfig updates from Nathan Chancellor:
"Kbuild:

- Remove broken module linking exclusion fo

Merge tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux

Pull Kbuild / Kconfig updates from Nathan Chancellor:
"Kbuild:

- Remove broken module linking exclusion for BTF

- Add documentation around how offset header files work

- Include unstripped vDSO libraries in pacman packages

- Bump minimum version of LLVM for building the kernel to 17.0.1 and
clean up unnecessary workarounds

- Use a context manager in run-clang-tools

- Add dist macro value if present to release tag for RPM packages

- Detect and report truncated buf_printf() output in modpost

- Add __llvm_covfun and __llvm_covmap to section whitelist in modpost

- Support Clang's distributed ThinLTO mode

- Remove architecture specific configurations for AutoFDO and
Propeller to ease individual architecture maintenance

Kconfig:

- Add kconfig-sym-check target to look for dangling Kconfig symbol
references and invalid tristate literal values

- Harden against potential NULL pointer dereference

- Fix typo in Kconfig test comment"

* tag 'kbuild-7.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux: (31 commits)
kconfig: tests: fix typo in comment
kconfig: Remove the architecture specific config for Propeller
kconfig: Remove the architecture specific config for AutoFDO
modpost: Add __llvm_covfun and __llvm_covmap to section_white_list
kconfig: add kconfig-sym-check static checker
kbuild: Remove unnecessary 'T' modifier in cmd_ar_builtin_fixup
kbuild: distributed build support for Clang ThinLTO
kbuild: move vmlinux.a build rule to scripts/Makefile.vmlinux_a
scripts: modpost: detect and report truncated buf_printf() output
kbuild: rpm-pkg: append %{?dist} macro to Release tag
run-clang-tools: run multiprocessing.Pool as context manager
compiler-clang.h: Drop explicit version number from "all" diagnostic macro
compiler-clang.h: Remove __cleanup -Wunused-variable workaround
kbuild: Remove check for broken scoping with clang < 17 in CC_HAS_ASM_GOTO_OUTPUT
x86/entry/vdso32: Remove conditional omission of '.cfi_offset eflags'
x86/module: Revert "Deal with GOT based stack cookie load on Clang < 17"
x86/build: Drop unnecessary '-ffreestanding' addition to KBUILD_CFLAGS
scripts/Makefile.warn: Drop -Wformat handling for clang < 16
riscv: Drop tautological condition from TOOLCHAIN_NEEDS_OLD_ISA_SPEC
riscv: Remove tautological condition from selection of ARCH_SUPPORTS_CFI
...

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kbuild: distributed build support for Clang ThinLTO

Add distributed ThinLTO build support for the Linux kernel.
This new mode offers several advantages: (1) Increased
flexibility in handling user-sp

kbuild: distributed build support for Clang ThinLTO

Add distributed ThinLTO build support for the Linux kernel.
This new mode offers several advantages: (1) Increased
flexibility in handling user-specified build options.
(2) Improved user-friendliness for developers. (3) Greater
convenience for integrating with objtool and livepatch.

Note that "distributed" in this context refers to a term
that differentiates in-process ThinLTO builds by invoking
backend compilation through the linker, not necessarily
building in distributed environments.

Distributed ThinLTO is enabled via the
`CONFIG_LTO_CLANG_THIN_DIST` Kconfig option. For example:
> make LLVM=1 defconfig
> scripts/config -e LTO_CLANG_THIN_DIST
> make LLVM=1 oldconfig
> make LLVM=1 vmlinux -j <..>

The build flow proceeds in four stages:
1. Perform FE compilation, mirroring the in-process ThinLTO mode.
2. Thin-link the generated IR files and object files.
3. Find all IR files and perform BE compilation, using the flags
stored in the .*.o.cmd files.
4. Link the BE results to generate the final vmlinux.o.

NOTE: This patch currently implements the build for the main kernel
image (vmlinux) only. Kernel module support is planned for a
subsequent patch.

Tested on the following arch: x86, arm64, loongarch, and
riscv.

The earlier implementation details can be found here:
https://discourse.llvm.org/t/rfc-distributed-thinlto-build-for-kernel/85934

Signed-off-by: Rong Xu <xur@google.com>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Piotr Gorski <piotrgorski@cachyos.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260529185347.2418373-4-xur@google.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

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