Pull more Kbuild updates from Nathan Chancellor:

 - Link host programs with ld.lld when $(LLVM) is set to match user's
   expectations that LLVM will be used exclusively during the build
   process

 - Fix modpost warnings from static variable name promotion that can
   happen more aggressively with the recently merged distributed ThinLTO
   support

 - Add an optional warning for user-supplied Kconfig values that changed
   after processing, such as out of range values or options that have
   incorrect / missing dependencies

* tag 'kbuild-7.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/kbuild/linux:
  kconfig: add optional warnings for changed input values
  modpost: Ignore Clang LTO suffixes in symbol matching
  kbuild: Use ld.lld for linking host programs when LLVM is set

When reading .config input, Kconfig stores user-provided values first
and then resolves the final value after applying dependencies, ranges,
and other constraints.

If the final value differs from the user input, Kconfig already tracks
that state internally, but it does not provide a focused diagnostic to
show which explicit inputs were adjusted. This is particularly confusing
for requested values that get forced down by unmet dependencies or
clamped by ranges.

Add an opt-in diagnostic controlled by KCONFIG_WARN_CHANGED_INPUT. Emit
the warnings from conf_write() and conf_write_defconfig() after value
resolution. Print the diagnostic to stderr directly, not through the
normal message callback, so it remains visible when conf is run with -s,
such as from make -s.

Keep the diagnostic out of the conf_message() formatting buffer so long
warning lists are not truncated, and mark processed symbols as written
before the SYMBOL_WRITE check so duplicate menu nodes cannot emit
duplicate warnings.

Document the new environment variable and add tests for olddefconfig,
savedefconfig, and the silent-conf path.

Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Tested-by: Julian Braha <julianbraha@gmail.com>
Link: https://patch.msgid.link/20260611060000.23858-1-pengpeng@iscas.ac.cn
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

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
  ...

scripts/kconfig/tests/no_write_if_dep_unmet/__init__.py contains a typo
"COFIG_" for "CONFIG_". Fix it.

Discovered while searching for typos in CONFIG_* variable references.

Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Link: https://patch.msgid.link/20260609021712.7965-1-enelsonmoore@gmail.com
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

The err_repeated_inc test was added with an expected stderr fixture
that does not match the diagnostic printed by kconfig.

Running "make testconfig" currently fails in that test even though the
parser reports the duplicated include correctly:

  [stderr]
  Kconfig.inc1:4: error: repeated inclusion of Kconfig.inc3
  Kconfig.inc2:3: note: location of first inclusion of Kconfig.inc3

The fixture expects "Repeated" and "Location" with capital letters, but
the diagnostic emitted by scripts/kconfig/util.c uses lowercase words.
Update the fixture to match the real message.

Fixes: 102d712ded3e ("kconfig: Error out on duplicated kconfig inclusion")
Signed-off-by: Zhou Yuhang <zhouyuhang@kylinos.cn>
Tested-by: Nicolas Schier <nsc@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260520070800.2265479-1-zhouyuhang1010@163.com
Signed-off-by: Nicolas Schier <nsc@kernel.org>

Let kconfig exit with error on duplicated Kconfig file inclusion.

Repeated inclusion of Kbuild files are considered bad-practise with
regard to maintenance; and Kconfig language is rich enough that there
should be no need for that.

If repeated inclusion of Kconfig files is detected, error out with
messages like:

    Kconfig.inc1:4: error: repeated inclusion of Kconfig.inc3
    Kconfig.inc2:3: note: location of first inclusion of Kconfig.inc3

While commit f094f8a1b273 ("kconfig: allow multiple inclusion of the
same file") introduced detection of recursive inclusions of Kconfig
files, it explicitly allowed repeated inclusions, unfortunately w/o
reasoning.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/all/CAHk-=wj03hLzK2D=+OYmjgcmGM+XYymp8GyaEs=C0=rXG2nb7w@mail.gmail.com/
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://patch.msgid.link/20260220-kconfig-error-out-on-duplicated-inclusion-v1-1-be78aa241a53@kernel.org
Signed-off-by: Nicolas Schier <nsc@kernel.org>

Extend the "depends on" syntax to support conditional dependencies
using "depends on X if Y". While functionally equivalent to "depends
on X || (Y == n)", "depends on X if Y" is much more readable and
makes the kconfig language uniform in supporting the "if <expr>"
suffix.
This also improves readability for "optional" dependencies, which
are the subset of conditional dependencies where X is Y.
Previously such optional dependencies had to be expressed as
the counterintuitive "depends on X || !X", now this can be
represented as "depends on X if X".

The change is implemented by converting the "X if Y" syntax into the
"X || (Y == n)" syntax during "depends on" token processing.

Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
[Graham Roff: Rewrote commit message, updated patch, added tests]
Signed-off-by: Graham Roff <grahamr@qti.qualcomm.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://patch.msgid.link/20251215-kconfig_conditional_deps-v3-1-59519af0a5df@qti.qualcomm.com
[nathan: Minor adjustments to spacing]
Signed-off-by: Nathan Chancellor <nathan@kernel.org>

The "transitional" symbol keyword, while working with the "olddefconfig"
target, was prompting during "oldconfig". This occurred because these
symbols were not being marked as user-defined when they received values
from transitional symbols that had user values. The "olddefconfig" target
explicitly doesn't prompt for anything, so this deficiency wasn't noticed.

The issue manifested when a symbol's value came from a transitional
symbol's user value but the receiving symbol wasn't marked with
SYMBOL_DEF_USER. Thus the "oldconfig" logic would then prompt for these
symbols unnecessarily.

Check after value calculation whether a symbol without a user value
gets its value from a single transitional symbol that does have a user
value. In such cases, mark the receiving symbol as user-defined to
prevent prompting.

Update regression tests to verify that symbols with transitional defaults
are not prompted in "oldconfig", except when conditional defaults evaluate
to 'no' and should legitimately be prompted.

Build tested with "make testconfig".

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Closes: https://lore.kernel.org/lkml/CAHk-=wgZjUk4Cy2XgNkTrQoO8XCmNUHrTe5D519Fij1POK+3qw@mail.gmail.com/
Fixes: f9afce4f32e9 ("kconfig: Add transitional symbol attribute for migration support")
Cc: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20250930154514.it.623-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

During kernel option migrations (e.g. CONFIG_CFI_CLANG to CONFIG_CFI),
existing .config files need to maintain backward compatibility while
preventing deprecated options from appearing in newly generated
configurations. This is challenging with existing Kconfig mechanisms
because:

1. Simply removing old options breaks existing .config files.
2. Manually listing an option as "deprecated" leaves it needlessly
   visible and still writes them to new .config files.
3. Using any method to remove visibility (.e.g no 'prompt', 'if n',
   etc) prevents the option from being processed at all.

Add a "transitional" attribute that creates symbols which are:
- Processed during configuration (can influence other symbols' defaults)
- Hidden from user menus (no prompts appear)
- Omitted from newly written .config files (gets migrated)
- Restricted to only having help sections (no defaults, selects, etc)
  making it truly just a "prior value pass-through" option.

The transitional syntax requires a type argument and prevents type
redefinition:

    config NEW_OPTION
        bool "New option"
        default OLD_OPTION

    config OLD_OPTION
        bool
        transitional
        help
          Transitional config for OLD_OPTION migration.

This allows seamless migration: olddefconfig processes existing
CONFIG_OLD_OPTION=y settings to enable CONFIG_NEW_OPTION=y, while
CONFIG_OLD_OPTION is omitted from newly generated .config files.

Added positive and negative testing via "testconfig" make target.

Co-developed-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250923213422.1105654-2-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>

The kconfig test harness ("make testconfig") was generating BrokenPipeError
warnings when running interactive tests like oldaskconfig and oldconfig:

  /usr/lib/python3/dist-packages/_pytest/unraisableexception.py:85: PytestUnraisableExceptionWarning: Exception ignored in: <_io.BufferedWriter name=12>

  Traceback (most recent call last):
    File "/srv/code/scripts/kconfig/tests/conftest.py", line 127, in oldaskconfig
      return self._run_conf('--oldaskconfig', dot_config=dot_config,
             ~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                            interactive=True, in_keys=in_keys)
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  BrokenPipeError: [Errno 32] Broken pipe

The issue occurred when the test framework attempted to write to stdin
after the conf subprocess had already exited.

Wrap stdin write operations in try/except to catch BrokenPipeError and
stop sending more input. Add explicit flush() after writes so we can see
delivery errors immediately. Ignore BrokenPipeError when closing stdin.
Explicitly call wait() to validate subprocess termination.

Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250923213422.1105654-1-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>