Currently the Kconfig fragments in kernel/configs and arch/*/configs
that aren't used internally aren't discoverable through "make help",
which consists of hard-coded lists of config fragments. Instead, list
all the fragment targets that have a "# Help: " comment prefix so the
targets can be generated dynamically.

Add logic to the Makefile to search for and display the fragment and
comment. Add comments to fragments that are intended to be direct targets.

Signed-off-by: Kees Cook <keescook@chromium.org>
Co-developed-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The modules_sign target is currently only available for in-tree modules,
but it actually works for external modules as well.

Move the modules_sign rule to the common part.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

Move more relevant code to scripts/Makefile.modinst.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

This reverts the old commit "kbuild: Introduce source symlink in
/lib/modules/.../". [1]

The current Kbuild does not require $(MODLIB)/source. If the kernel was
built in a separate output directory, $(MODLIB)/build/Makefile wraps
the Makefile in the source tree. It is enough for building external
modules.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/commit/?id=e09e58867154b8aae0a3ac26a9b1c05962f5a355



Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

depmod is a part of the module installation.

scripts/Makefile.modinst is a better place to run it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

Like modules_install, modules_sign should avoid the syncconfig.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

Commit 961ab4a3 ("kbuild: merge scripts/Makefile.modsign to
scripts/Makefile.modinst") started to run depmod at the end of
'make modules_sign'.

Move the depmod rule to scripts/Makefile.modinst and run it only when
$(modules_sign_only) is empty.

Fixes: 961ab4a3 ("kbuild: merge scripts/Makefile.modsign to scripts/Makefile.modinst")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

This is a remnant of commit 5e9e95cc ("kbuild: implement
CONFIG_TRIM_UNUSED_KSYMS without recursion").

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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 <arnd@arndb.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Introduced in Rust 1.69.0 [1], this lint prevents forgetting to set
the C ABI when using `#[no_mangle]` (or thinking it is implied).

For instance, it would have prevented the issue [2] fixed by commit
c682e4c3 ("rust: kernel: Mark rust_fmt_argument as extern "C"").

    error: `#[no_mangle]` set on a function with the default (`Rust`) ABI
      --> rust/kernel/print.rs:21:1
       |
    21 | / unsafe fn rust_fmt_argument(
    22 | |     buf: *mut c_char,
    23 | |     end: *mut c_char,
    24 | |     ptr: *const c_void,
    25 | | ) -> *mut c_char {
       | |________________^
       |
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#no_mangle_with_rust_abi
       = note: requested on the command line with `-D clippy::no-mangle-with-rust-abi`
    help: set an ABI
       |
    21 | unsafe extern "C" fn rust_fmt_argument(
       |        ++++++++++
    help: or explicitly set the default
       |
    21 | unsafe extern "Rust" fn rust_fmt_argument(
       |        +++++++++++++

Thus enable it.

In rare cases, we may need to use the Rust ABI even with `#[no_mangle]`
(e.g. one case, before 1.71.0, would have been the `__rust_*`
functions). In those cases, we would need to `#[allow(...)]` the lint,
since using `extern "Rust"` explicitly (as the compiler suggests)
currently gets overwritten by `rustfmt` [3].

Link: https://github.com/rust-lang/rust-clippy/issues/10347 [1]
Link: https://github.com/Rust-for-Linux/linux/pull/967 [2]
Link: https://github.com/rust-lang/rustfmt/issues/5701

 [3]
Reviewed-by: Trevor Gross <tmgross@umich.edu>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230729220317.416771-2-ojeda@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

The -v option is passed when this script is invoked from Makefile,
but not when invoked from Kconfig.

As you can see in scripts/Kconfig.include, the 'success' macro suppresses
stdout and stderr anyway, so this script does not need to be quiet.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Miguel Ojeda <ojeda@kernel.org>
Tested-by: Miguel Ojeda <ojeda@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20230109061436.3146442-1-masahiroy@kernel.org


[ Reworded prefix to match the others in the patch series. ]
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Link: https://lore.kernel.org/r/20230616001631.463536-2-ojeda@kernel.org


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Adds support for out-of-tree rust modules to use the `rust-analyzer`
make target to generate the rust-project.json file.

The change involves adding an optional parameter `external_src` to the
`generate_rust_analyzer.py` which expects the path to the out-of-tree
module's source directory. When this parameter is passed, I have chosen
not to add the non-core modules (samples and drivers) into the result
since these are not expected to be used in third party modules. Related
changes are also made to the Makefile and rust/Makefile allowing the
`rust-analyzer` target to be used for out-of-tree modules as well.

Link: https://github.com/Rust-for-Linux/linux/pull/914
Link: https://github.com/Rust-for-Linux/rust-out-of-tree-module/pull/2


Signed-off-by: Vinay Varma <varmavinaym@gmail.com>
Link: https://lore.kernel.org/r/20230411091714.130525-1-varmavinaym@gmail.com


Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

Now kernel.spec and binkernel.spec have the exactly same contents.

Use kernel.spec for binrpm-pkg as well.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

There are some cases where we want to run a command with the same
environment variables as Kbuild uses. For example, 'make coccicheck'
invokes scripts/coccicheck from the top Makefile so that the script can
reference to ${LINUXINCLUDE}, ${KBUILD_EXTMOD}, etc. The top Makefile
defines several phony targets that run a script.

We do it also for an internally used script, which results in a somewhat
complex call graph.

One example:

 debian/rules binary-arch
   -> make intdeb-pkg
      -> scripts/package/builddeb

It is also tedious to add a dedicated target like 'intdeb-pkg' for each
use case.

Add a generic target 'run-command' to run an arbitrary command in an
environment with all Kbuild variables set.

The usage is:

  $ make run-command KBUILD_RUN_COMMAND=<command>

The concept is similar to:

  $ dpkg-architecture -c <command>

This executes <command> in an environment which has all DEB_* variables
defined.

Convert the existing 'make intdeb-pkg'.

Another possible usage is to interrogate a Make variable.

  $ make run-command KBUILD_RUN_COMMAND='echo $(KBUILD_CFLAGS)'

might be useful to see KBUILD_CFLAGS set by the top Makefile.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

This diagnostic checks whether there is a type mismatch when
converting enums (assign an enum of type A to an enum of type B, for
example) and it caught a legit issue recently. The reason it didn't show
is because that warning is enabled only with -Wextra with GCC. Clang,
however, enables it by default.

GCC folks were considering enabling it by default but it was too noisy
back then:

  https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78736



Now that due to clang all those warnings have been fixed, enable it with
GCC too.

allmodconfig tests done with: x86, arm{,64}, powerpc{,64}, riscv
crossbuilds.

Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

Make it slightly easier to see which compiler options are added and
removed (and not worry about column limit too!).

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

With commit 9da0763b ("kbuild: Use relative path when building in
a subdir of the source tree"), compiler messages in out-of-tree builds
include relative paths, which are relative to the build directory, not
the directory where make was started.

To help IDEs/editors find the source files, Kbuild lets GNU Make print
"Entering directory ..." when it changes the working directory. It has
been working fine for a long time, but David reported it is broken with
the latest GNU Make.

The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537]
Fix setting -w in makefiles"). Previously, setting --no-print-directory
to MAKEFLAGS only affected child makes, but it is now interpreted in
the current make as soon as it is set.

[test code]

  $ cat /tmp/Makefile
  ifneq ($(SUBMAKE),1)
  MAKEFLAGS += --no-print-directory
  all: ; $(MAKE) SUBMAKE=1
  else
  all: ; :
  endif

[before 8f9e7722ff0f]

  $ make -C /tmp
  make: Entering directory '/tmp'
  make SUBMAKE=1
  :
  make: Leaving directory '/tmp'

[after 8f9e7722ff0f]

  $ make -C /tmp
  make SUBMAKE=1
  :

Previously, the effect of --no-print-directory was delayed until Kbuild
started the directory descending, but it is no longer true with GNU Make
4.4.1.

This commit adds one more recursion to cater to GNU Make >= 4.4.1.

When Kbuild needs to change the working directory, __submake will be
executed twice.

  __submake without --no-print-directory  --> show "Entering directory ..."
  __submake with    --no-print-directory  --> parse the rest of Makefile

We end up with one more recursion than needed for GNU Make < 4.4.1, but
I do not want to complicate the version check.

Reported-by: David Howells <dhowells@redhat.com>
Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/


Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Nicolas Schier <n.schier@avm.de>

When you run 'make rpm-pkg', the rpmbuild tool builds the kernel in
rpmbuild/BUILD, but $(abs_srctree) and $(abs_objtree) point to the
directory path where make was started, not the kernel is actually
being built. The same applies to 'make snap-pkg'. Fix it.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

With the advent on scope-based resource management it comes really
tedious to abide by the contraints of -Wdeclaration-after-statement.

It will still be recommeneded to place declarations at the start of a
scope where possible, but it will no longer be enforced.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/CAHk-%3Dwi-RyoUhbChiVaJZoZXheAwnJ7OO%3DGxe85BkPAd93TwDA%40mail.gmail.com

Josh Triplett reports that initramfs-tools needs modules.builtin and
modules.builtin.modinfo to create a working initramfs for a non-modular
kernel.

If this is a general tooling issue not limited to Debian, I think it
makes sense to change modules_install.

This commit changes the targets as follows when CONFIG_MODULES=n.

In-tree builds:
  make modules          -> no-op
  make modules_install  -> install modules.builtin(.modinfo)

External module builds:
  make modules          -> show error message like before
  make modules_install  -> show error message like before

Link: https://lore.kernel.org/lkml/36a4014c73a52af27d930d3ca31d362b60f4461c.1686356364.git.josh@joshtriplett.org/


Reported-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Tested-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Tested-by: Josh Triplett <josh@joshtriplett.org>

When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses
the directory tree to determine which EXPORT_SYMBOL to trim. If an
EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the
second traverse, where some source files are recompiled with their
EXPORT_SYMBOL() tuned into a no-op.

Linus stated negative opinions about this slowness in commits:

 - 5cf0fd59 ("Kbuild: disable TRIM_UNUSED_KSYMS option")
 - a555bdd0 ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding")

We can do this better now. The final data structures of EXPORT_SYMBOL
are generated by the modpost stage, so modpost can selectively emit
KSYMTAB entries that are really used by modules.

Commit f73edc89 ("kbuild: unify two modpost invocations") is another
ground-work to do this in a one-pass algorithm. With the list of modules,
modpost sets sym->used if it is used by a module. modpost emits KSYMTAB
only for symbols with sym->used==true.

BTW, Nicolas explained why the trimming was implemented with recursion:

  https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/



Actually, we never achieved that level of optimization where the chain
reaction of trimming comes into play because:

 - CONFIG_LTO_CLANG cannot remove any unused symbols
 - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux,
   but not modules

If deeper trimming is required, we need to revisit this, but I guess
that is unlikely to happen.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

The -fstrict-flex-arrays=3 option is now available with the release
of GCC 13[1] and Clang 16[2]. This feature instructs the compiler to
treat only C99 flexible arrays as dynamically sized for the purposes of
object size calculations. In other words, the ancient practice of using
1-element arrays, or the GNU extension of using 0-sized arrays, as a
dynamically sized array is disabled. This allows CONFIG_UBSAN_BOUNDS,
CONFIG_FORTIFY_SOURCE, and other object-size aware features to behave
unambiguously in the face of trailing arrays: only C99 flexible arrays
are considered to be dynamically sized. For yet more detail, see:
https://people.kernel.org/kees/bounded-flexible-arrays-in-c

Enabling this will help track down any outstanding cases of fake
flexible arrays that need attention in kernel code.

[1] https://gcc.gnu.org/onlinedocs/gcc/C-Dialect-Options.html#index-fstrict-flex-arrays
[2] https://clang.llvm.org/docs/ClangCommandLineReference.html#cmdoption-clang-fstrict-flex-arrays



Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: linux-kbuild@vger.kernel.org
Co-developed-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>

Commit 27f2a4db ("Makefile: fix GDB warning with CONFIG_RELR")
added --use-android-relr-tags to fix a GDB warning

BFD: /android0/linux-next/vmlinux: unknown type [0x13] section `.relr.dyn'

The GDB warning has been fixed in version 11.2.

The DT_ANDROID_RELR tag was deprecated since DT_RELR was standardized.
Thus, --use-android-relr-tags should be removed. While making the
change, try -z pack-relative-relocs, which is supported since LLD 15.
Keep supporting --pack-dyn-relocs=relr as well for older LLD versions.
There is no indication of obsolescence for --pack-dyn-relocs=relr.

As of today, GNU ld supports the latter option for x86 and powerpc64
ports and has no intention to support --pack-dyn-relocs=relr. In the
absence of the glibc symbol version GLIBC_ABI_DT_RELR,
--pack-dyn-relocs=relr and -z pack-relative-relocs are identical in
ld.lld.

GNU ld and newer versions of LLD report warnings (instead of errors) for
unknown -z options. Only errors lead to non-zero exit codes. Therefore,
we should test --pack-dyn-relocs=relr before testing
-z pack-relative-relocs.

Link: https://github.com/ClangBuiltLinux/linux/issues/1057
Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=a619b58721f0a03fd91c27670d3e4c2fb0d88f1e


Signed-off-by: Fangrui Song <maskray@google.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>