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Pull Rust fixes from Miguel Ojeda:
"Toolchain and infrastructure:
- Fix builds for nightly compiler users now that 'new_uninit' was
split into new features by using an alternative approach for the
code that used what is now called the 'box_uninit_write' feature
- Allow the 'stable_features' lint to preempt upcoming warnings about
them, since soon there will be unstable features that will become
stable in nightly compilers
- Export bss symbols too
'kernel' crate:
- 'block' module: fix wrong usage of lockdep API
'macros' crate:
- Provide correct provenance when constructing 'THIS_MODULE'
Documentation:
- Remove unintended indentation (blockquotes) in generated output
- Fix a couple typos
MAINTAINERS:
- Remove Wedson as Rust maintainer
- Update Andreas' email"
* tag 'rust-fixes-6.11-2' of https://github.com/Rust-for-Linux/linux:
MAINTAINERS: update Andreas Hindborg's email address
MAINTAINERS: Remove Wedson as Rust maintainer
rust: macros: provide correct provenance when constructing THIS_MODULE
rust: allow `stable_features` lint
docs: rust: remove unintended blockquote in Quick Start
rust: alloc: eschew `Box<MaybeUninit<T>>::write`
rust: kernel: fix typos in code comments
docs: rust: remove unintended blockquote in Coding Guidelines
rust: block: fix wrong usage of lockdep API
rust: kbuild: fix export of bss symbols
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Support for several Rust compiler versions started in commit 63b27f4a0074
("rust: start supporting several compiler versions"). Since we currently
need to use a number of unstable features in the kernel, it is a matter
of time until one gets stabilized and the `stable_features` lint warns.
For instance, the `new_uninit` feature may become stable soon, which
would give us multiple warnings like the following:
warning: the feature `new_uninit` has been stable since 1.82.0-dev
and no longer requires an attribute to enable
--> rust/kernel/lib.rs:17:12
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17 | #![feature(new_uninit)]
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= note: `#[warn(stable_features)]` on by default
Thus allow the `stable_features` lint to avoid such warnings. This is
the simplest approach -- we do not have that many cases (and the goal
is to stop using unstable features anyway) and cleanups can be easily
done when we decide to update the minimum version.
An alternative would be to conditionally enable them based on the
compiler version (with the upcoming `RUSTC_VERSION` or maybe with the
unstable `cfg(version(...))`, but that one apparently will not work for
the nightly case). However, doing so is more complex and may not work
well for different nightlies of the same version, unless we do not care
about older nightlies.
Another alternative is using explicit tests of the feature calling
`rustc`, but that is also more complex and slower.
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240827100403.376389-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- Eliminate the fdtoverlay command duplication in scripts/Makefile.lib
- Fix 'make compile_commands.json' for external modules
- Ensure scripts/kconfig/merge_config.sh handles missing newlines
- Fix some build errors on macOS
* tag 'kbuild-fixes-v6.11-2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: fix typos "prequisites" to "prerequisites"
Documentation/llvm: turn make command for ccache into code block
kbuild: avoid scripts/kallsyms parsing /dev/null
treewide: remove unnecessary <linux/version.h> inclusion
scripts: kconfig: merge_config: config files: add a trailing newline
Makefile: add $(srctree) to dependency of compile_commands.json target
kbuild: clean up code duplication in cmd_fdtoverlay
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Pull rust fixes from Miguel Ojeda:
- Fix '-Os' Rust 1.80.0+ builds adding more intrinsics (also tweaked in
upstream Rust for the upcoming 1.82.0).
- Fix support for the latest version of rust-analyzer due to a change
on rust-analyzer config file semantics (considered a fix since most
developers use the latest version of the tool, which is the only one
actually supported by upstream). I am discussing stability of the
config file with upstream -- they may be able to start versioning it.
- Fix GCC 14 builds due to '-fmin-function-alignment' not skipped for
libclang (bindgen).
- A couple Kconfig fixes around '{RUSTC,BINDGEN}_VERSION_TEXT' to
suppress error messages in a foreign architecture chroot and to use a
proper default format.
- Clean 'rust-analyzer' target warning due to missing recursive make
invocation mark.
- Clean Clippy warning due to missing indentation in docs.
- Clean LLVM 19 build warning due to removed 3dnow feature upstream.
* tag 'rust-fixes-6.11' of https://github.com/Rust-for-Linux/linux:
rust: x86: remove `-3dnow{,a}` from target features
kbuild: rust-analyzer: mark `rust_is_available.sh` invocation as recursive
rust: add intrinsics to fix `-Os` builds
kbuild: rust: skip -fmin-function-alignment in bindgen flags
rust: Support latest version of `rust-analyzer`
rust: macros: indent list item in `module!`'s docs
rust: fix the default format for CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT
rust: suppress error messages from CONFIG_{RUSTC,BINDGEN}_VERSION_TEXT
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When calling the `rust_is_available.sh` script, we need to make the
jobserver available to it, as commit ecab4115c44c ("kbuild: mark `rustc`
(and others) invocations as recursive") explains and did for the others.
Otherwise, we get a warning from `rustc` when calling `make rust-analyzer`
with parallel jobs, e.g. `-j8`. Using several jobs for that target does
not really matter, but developers may call `make` with jobs enabled in
all cases.
Thus fix it.
Fixes: 6dc9d9ca9a72 ("kbuild: rust-analyzer: better error handling")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240806233559.246705-1-ojeda@kernel.org
[ Reworded to add a couple more details mentioned in the list. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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When trying to build compile_commands.json for an external module against
the kernel built in a separate output directory, the following error is
displayed:
make[1]: *** No rule to make target 'scripts/clang-tools/gen_compile_commands.py',
needed by 'compile_commands.json'. Stop.
This is because gen_compile_commands.py was previously looked up using a
relative path to $(srctree), but commit b1992c3772e6 ("kbuild: use
$(src) instead of $(srctree)/$(src) for source directory") stopped
defining VPATH for external module builds.
Prefixing gen_compile_commands.py with $(srctree) fixes the problem.
Fixes: b1992c3772e6 ("kbuild: use $(src) instead of $(srctree)/$(src) for source directory")
Signed-off-by: Alexandre Courbot <gnurou@gmail.com>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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Pull Rust updates from Miguel Ojeda:
"The highlight is the establishment of a minimum version for the Rust
toolchain, including 'rustc' (and bundled tools) and 'bindgen'.
The initial minimum will be the pinned version we currently have, i.e.
we are just widening the allowed versions. That covers three stable
Rust releases: 1.78.0, 1.79.0, 1.80.0 (getting released tomorrow),
plus beta, plus nightly.
This should already be enough for kernel developers in distributions
that provide recent Rust compiler versions routinely, such as Arch
Linux, Debian Unstable (outside the freeze period), Fedora Linux,
Gentoo Linux (especially the testing channel), Nix (unstable) and
openSUSE Slowroll and Tumbleweed.
In addition, the kernel is now being built-tested by Rust's pre-merge
CI. That is, every change that is attempting to land into the Rust
compiler is tested against the kernel, and it is merged only if it
passes. Similarly, the bindgen tool has agreed to build the kernel in
their CI too.
Thus, with the pre-merge CI in place, both projects hope to avoid
unintentional changes to Rust that break the kernel. This means that,
in general, apart from intentional changes on their side (that we will
need to workaround conditionally on our side), the upcoming Rust
compiler versions should generally work.
In addition, the Rust project has proposed getting the kernel into
stable Rust (at least solving the main blockers) as one of its three
flagship goals for 2024H2 [1].
I would like to thank Niko, Sid, Emilio et al. for their help
promoting the collaboration between Rust and the kernel.
Toolchain and infrastructure:
- Support several Rust toolchain versions.
- Support several bindgen versions.
- Remove 'cargo' requirement and simplify 'rusttest', thanks to
'alloc' having been dropped last cycle.
- Provide proper error reporting for the 'rust-analyzer' target.
'kernel' crate:
- Add 'uaccess' module with a safe userspace pointers abstraction.
- Add 'page' module with a 'struct page' abstraction.
- Support more complex generics in workqueue's 'impl_has_work!'
macro.
'macros' crate:
- Add 'firmware' field support to the 'module!' macro.
- Improve 'module!' macro documentation.
Documentation:
- Provide instructions on what packages should be installed to build
the kernel in some popular Linux distributions.
- Introduce the new kernel.org LLVM+Rust toolchains.
- Explain '#[no_std]'.
And a few other small bits"
Link: https://rust-lang.github.io/rust-project-goals/2024h2/index.html#flagship-goals [1]
* tag 'rust-6.11' of https://github.com/Rust-for-Linux/linux: (26 commits)
docs: rust: quick-start: add section on Linux distributions
rust: warn about `bindgen` versions 0.66.0 and 0.66.1
rust: start supporting several `bindgen` versions
rust: work around `bindgen` 0.69.0 issue
rust: avoid assuming a particular `bindgen` build
rust: start supporting several compiler versions
rust: simplify Clippy warning flags set
rust: relax most deny-level lints to warnings
rust: allow `dead_code` for never constructed bindings
rust: init: simplify from `map_err` to `inspect_err`
rust: macros: indent list item in `paste!`'s docs
rust: add abstraction for `struct page`
rust: uaccess: add typed accessors for userspace pointers
uaccess: always export _copy_[from|to]_user with CONFIG_RUST
rust: uaccess: add userspace pointers
kbuild: rust-analyzer: improve comment documentation
kbuild: rust-analyzer: better error handling
docs: rust: no_std is used
rust: alloc: add __GFP_HIGHMEM flag
rust: alloc: fix typo in docs for GFP_NOWAIT
...
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Remove tristate choice support from Kconfig
- Stop using the PROVIDE() directive in the linker script
- Reduce the number of links for the combination of CONFIG_KALLSYMS and
CONFIG_DEBUG_INFO_BTF
- Enable the warning for symbol reference to .exit.* sections by
default
- Fix warnings in RPM package builds
- Improve scripts/make_fit.py to generate a FIT image with separate
base DTB and overlays
- Improve choice value calculation in Kconfig
- Fix conditional prompt behavior in choice in Kconfig
- Remove support for the uncommon EMAIL environment variable in Debian
package builds
- Remove support for the uncommon "name <email>" form for the DEBEMAIL
environment variable
- Raise the minimum supported GNU Make version to 4.0
- Remove stale code for the absolute kallsyms
- Move header files commonly used for host programs to scripts/include/
- Introduce the pacman-pkg target to generate a pacman package used in
Arch Linux
- Clean up Kconfig
* tag 'kbuild-v6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (65 commits)
kbuild: doc: gcc to CC change
kallsyms: change sym_entry::percpu_absolute to bool type
kallsyms: unify seq and start_pos fields of struct sym_entry
kallsyms: add more original symbol type/name in comment lines
kallsyms: use \t instead of a tab in printf()
kallsyms: avoid repeated calculation of array size for markers
kbuild: add script and target to generate pacman package
modpost: use generic macros for hash table implementation
kbuild: move some helper headers from scripts/kconfig/ to scripts/include/
Makefile: add comment to discourage tools/* addition for kernel builds
kbuild: clean up scripts/remove-stale-files
kconfig: recursive checks drop file/lineno
kbuild: rpm-pkg: introduce a simple changelog section for kernel.spec
kallsyms: get rid of code for absolute kallsyms
kbuild: Create INSTALL_PATH directory if it does not exist
kbuild: Abort make on install failures
kconfig: remove 'e1' and 'e2' macros from expression deduplication
kconfig: remove SYMBOL_CHOICEVAL flag
kconfig: add const qualifiers to several function arguments
kconfig: call expr_eliminate_yn() at least once in expr_eliminate_dups()
...
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pacman is the package manager used by Arch Linux and its derivates.
Creating native packages from the kernel tree has multiple advantages:
* The package triggers the correct hooks for initramfs generation and
bootloader configuration
* Uninstallation is complete and also invokes the relevant hooks
* New UAPI headers can be installed without any manual bookkeeping
The PKGBUILD file is a modified version of the one used for the
downstream Arch Linux "linux" package.
Extra steps that should not be necessary for a development kernel have
been removed and an UAPI header package has been added.
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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Move array_size.h, hashtable.h, list.h, list_types.h from scripts/kconfig/
to scripts/include/.
These headers will be useful for other host programs.
Remove scripts/mod/list.h.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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Kbuild provides scripts/Makefile.host to build host programs used for
building the kernel. Unfortunately, there are two exceptions that opt
out of Kbuild. The build system under tools/ is a cheesy replica, and
cause issues. I was recently poked about a problem in the tools build
system, which I do not maintain (and nobody maintains). [1]
Without a comment, people might believe this is the right location
because that is where objtool lives, even if a more robust Kbuild
syntax satisfies their needs. [2]
[1]: https://lore.kernel.org/linux-kbuild/ZnIYWBgrJ-IJtqK8@google.com/T/#m8ece130dd0e23c6f2395ed89070161948dee8457
[2]: https://lore.kernel.org/all/20240618200501.GA1611012@google.com/
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Brian Norris <briannorris@chromium.org>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"Most of this is part of my ongoing work to clean up the system call
tables. In this bit, all of the newer architectures are converted to
use the machine readable syscall.tbl format instead in place of
complex macros in include/uapi/asm-generic/unistd.h.
This follows an earlier series that fixed various API mismatches and
in turn is used as the base for planned simplifications.
The other two patches are dead code removal and a warning fix"
* tag 'asm-generic-6.11' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
vmlinux.lds.h: catch .bss..L* sections into BSS")
fixmap: Remove unused set_fixmap_offset_io()
riscv: convert to generic syscall table
openrisc: convert to generic syscall table
nios2: convert to generic syscall table
loongarch: convert to generic syscall table
hexagon: use new system call table
csky: convert to generic syscall table
arm64: rework compat syscall macros
arm64: generate 64-bit syscall.tbl
arm64: convert unistd_32.h to syscall.tbl format
arc: convert to generic syscall table
clone3: drop __ARCH_WANT_SYS_CLONE3 macro
kbuild: add syscall table generation to scripts/Makefile.asm-headers
kbuild: verify asm-generic header list
loongarch: avoid generating extra header files
um: don't generate asm/bpf_perf_event.h
csky: drop asm/gpio.h wrapper
syscalls: add generic scripts/syscall.tbl
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RHEL/CentOS 7, popular distributions that install GNU Make 3.82, reached
EOM/EOL on June 30, 2024. While you may get extended support, it is a
good time to raise the minimum GNU Make version.
The new requirement, GNU Make 4.0, was released in October, 2013.
I did not touch the Makefiles under tools/ because I do not know the
requirements for building tools. I do not find any GNU Make version
checks under tools/.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
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There are 11 copies of arch/*/kernel/syscalls/Makefile that all implement
the same basic logic in a somewhat awkward way.
I tried out various ways of unifying the existing copies and ended up
with something that hooks into the logic for generating the redirections
to asm-generic headers. This gives a nicer syntax of being able to list
the generated files in $(syscall-y) inside of arch/*/include/asm/Kbuild
instead of both $(generated-y) in that place and also in another
Makefile.
The configuration for which syscall.tbl file to use and which ABIs to
enable is now done in arch/*/kernel/Makefile.syscalls. I have done
patches for all architectures and made sure that the new generic
rules implement a superset of all the architecture specific corner
cases.
ince the header file is not specific to asm-generic/*.h redirects
now, I ended up renaming the file to scripts/Makefile.asm-headers.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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All Clippy lint groups that we enable, except `correctness`, have a
default `warn` level, thus they may be removed now that we relaxed all
lints to `warn`.
Moreover, Clippy provides an `all` lint group that covers the groups
we enable by default. Thus just use `all` instead -- the only change is
that, if Clippy introduces a new lint group or splits an existing one,
we will cover that one automatically.
In addition, `let_unit_value` is in `style` since Rust 1.62.0, thus it
does not need to be enabled manually.
Reviewed-by: Finn Behrens <me@kloenk.dev>
Tested-by: Benno Lossin <benno.lossin@proton.me>
Tested-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20240709160615.998336-6-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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Since we are starting to support several Rust toolchains, lints (including
Clippy ones) now may behave differently and lint groups may include
new lints.
Therefore, to maximize the chances a given version works, relax some
deny-level lints to warnings. It may also make our lives a bit easier
while developing new code or refactoring.
To be clear, the requirements for in-tree code are still the same, since
Rust code still needs to be warning-free (patches should be clean under
`WERROR=y`) and the set of lints is not changed.
`unsafe_op_in_unsafe_fn` is left unmodified, i.e. as an error, since it is
becoming the default in the language (warn-by-default in Rust 2024 [1] and
ideally an error later on) and thus it should also be very well tested. In
addition, it is simple enough that it should not have false positives
(unlike e.g. `rust_2018_idioms`'s `explicit_outlives_requirements`).
`non_ascii_idents` is left unmodified as well, i.e. as an error, since
it is unlikely one gains any productivity during development if it
were a warning (in fact, it may be worse, since it is likely one made
a typo). In addition, it should not have false positives.
Finally, put the two `-D` ones at the top and take the chance to do one
per line.
Link: https://github.com/rust-lang/rust/pull/112038 [1]
Reviewed-by: Finn Behrens <me@kloenk.dev>
Tested-by: Benno Lossin <benno.lossin@proton.me>
Tested-by: Andreas Hindborg <a.hindborg@samsung.com>
Link: https://lore.kernel.org/r/20240709160615.998336-5-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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Replace the cryptic phrase ("IDE support targets") that initially
appears to be about how to support old hard drives, with a few sentences
that explain what "make rust-analyzer" provides.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Finn Behrens <me@kloenk.dev>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240628004356.1384486-3-jhubbard@nvidia.com
[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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1) Provide a better error message for the "Rust not available" case.
Without this patch, one gets various misleading messages, such as:
"No rule to make target 'rust-analyzer'"
Instead, run scripts/rust_is_available.sh directly, as a prerequisite,
and let that script report the cause of any problems, as well as
providing a link to the documentation. Thanks to Miguel Ojeda for the
idea of just letting rust_is_available.sh report its results directly.
The new output in the failure case looks like this:
$ make rust-analyzer
***
*** Rust compiler 'rustc' could not be found.
***
***
*** Please see Documentation/rust/quick-start.rst for details
*** on how to set up the Rust support.
***
make[1]: *** [/kernel_work/linux-github/Makefile:1975: rust-analyzer] Error 1
make: *** [Makefile:240: __sub-make] Error 2
Reviewed-by: Finn Behrens <me@kloenk.dev>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Tested-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Link: https://lore.kernel.org/r/20240628004356.1384486-2-jhubbard@nvidia.com
[ Reworded title. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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Since we dropped our custom `alloc` in commit 9d0441bab775 ("rust: alloc:
remove our fork of the `alloc` crate"), there is no need anymore to keep
the custom sysroot hack.
Thus delete it, which makes the target way simpler and faster too.
This also means we are not using Cargo for anything at the moment,
and that no download is required anymore, so update the main `Makefile`
and the documentation accordingly.
Link: https://lore.kernel.org/r/20240528163502.411600-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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Several architectures provide an API to enable the FPU and run
floating-point SIMD code in kernel space. However, the function names,
header locations, and semantics are inconsistent across architectures, and
FPU support may be gated behind other Kconfig options.
provide a standard way for architectures to declare that kernel space
FPU support is available. Architectures selecting this option must
implement what is currently the most common API (kernel_fpu_begin() and
kernel_fpu_end(), plus a new function kernel_fpu_available()) and
provide the appropriate CFLAGS for compiling floating-point C code.
Link: https://lkml.kernel.org/r/20240329072441.591471-2-samuel.holland@sifive.com
Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Suggested-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicolas Schier <nicolas@fjasle.eu>
Cc: Palmer Dabbelt <palmer@rivosinc.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: WANG Xuerui <git@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild updates from Masahiro Yamada:
- Avoid 'constexpr', which is a keyword in C23
- Allow 'dtbs_check' and 'dt_compatible_check' run independently of
'dt_binding_check'
- Fix weak references to avoid GOT entries in position-independent code
generation
- Convert the last use of 'optional' property in arch/sh/Kconfig
- Remove support for the 'optional' property in Kconfig
- Remove support for Clang's ThinLTO caching, which does not work with
the .incbin directive
- Change the semantics of $(src) so it always points to the source
directory, which fixes Makefile inconsistencies between upstream and
downstream
- Fix 'make tar-pkg' for RISC-V to produce a consistent package
- Provide reasonable default coverage for objtool, sanitizers, and
profilers
- Remove redundant OBJECT_FILES_NON_STANDARD, KASAN_SANITIZE, etc.
- Remove the last use of tristate choice in drivers/rapidio/Kconfig
- Various cleanups and fixes in Kconfig
* tag 'kbuild-v6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (46 commits)
kconfig: use sym_get_choice_menu() in sym_check_prop()
rapidio: remove choice for enumeration
kconfig: lxdialog: remove initialization with A_NORMAL
kconfig: m/nconf: merge two item_add_str() calls
kconfig: m/nconf: remove dead code to display value of bool choice
kconfig: m/nconf: remove dead code to display children of choice members
kconfig: gconf: show checkbox for choice correctly
kbuild: use GCOV_PROFILE and KCSAN_SANITIZE in scripts/Makefile.modfinal
Makefile: remove redundant tool coverage variables
kbuild: provide reasonable defaults for tool coverage
modules: Drop the .export_symbol section from the final modules
kconfig: use menu_list_for_each_sym() in sym_check_choice_deps()
kconfig: use sym_get_choice_menu() in conf_write_defconfig()
kconfig: add sym_get_choice_menu() helper
kconfig: turn defaults and additional prompt for choice members into error
kconfig: turn missing prompt for choice members into error
kconfig: turn conf_choice() into void function
kconfig: use linked list in sym_set_changed()
kconfig: gconf: use MENU_CHANGED instead of SYMBOL_CHANGED
kconfig: gconf: remove debug code
...
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Currently, Kbuild produces inconsistent results in some cases.
You can do an interesting experiment using the --shuffle option, which
is supported by GNU Make 4.4 or later.
Set CONFIG_KVM_INTEL=y and CONFIG_KVM_AMD=m (or vice versa), and repeat
incremental builds w/wo --shuffle=reverse.
$ make
[ snip ]
CC arch/x86/kvm/kvm-asm-offsets.s
$ make --shuffle=reverse
[ snip ]
CC [M] arch/x86/kvm/kvm-asm-offsets.s
$ make
[ snip ]
CC arch/x86/kvm/kvm-asm-offsets.s
arch/x86/kvm/kvm-asm-offsets.s is rebuilt every time w/wo the [M] marker.
arch/x86/kvm/kvm-asm-offsets.s is built as built-in when it is built as
a prerequisite of arch/x86/kvm/kvm-intel.o, which is built-in.
arch/x86/kvm/kvm-asm-offsets.s is built as modular when it is built as
a prerequisite of arch/x86/kvm/kvm-amd.o, which is a module.
Another odd example is single target builds.
When CONFIG_LKDTM=m, drivers/misc/lkdtm/rodata.o can be built as
built-in or modular, depending on how it is built.
$ make drivers/misc/lkdtm/lkdtm.o
[ snip ]
CC [M] drivers/misc/lkdtm/rodata.o
$ make drivers/misc/lkdtm/rodata.o
[ snip ]
CC drivers/misc/lkdtm/rodata.o
drivers/misc/lkdtm/rodata.o is built as modular when it is built as a
prerequisite of another, but built as built-in when it is a final
target.
The same thing happens to drivers/memory/emif-asm-offsets.s when
CONFIG_TI_EMIF_SRAM=m.
$ make drivers/memory/ti-emif-sram.o
[ snip ]
CC [M] drivers/memory/emif-asm-offsets.s
$ make drivers/memory/emif-asm-offsets.s
[ snip ]
CC drivers/memory/emif-asm-offsets.s
This is because the part-of-module=y flag defined for the modules is
inherited by its prerequisites.
Target-specific variables are likely intended only for local use.
This commit adds 'private' to them.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
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The $(wildcard ) is called in quiet_cmd_rmfiles.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <n.schier@avm.de>
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Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:
src := $(obj)
When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.
This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.
To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.
Going forward, the variables used in Makefiles will have the following
meanings:
$(obj) - directory in the object tree
$(src) - directory in the source tree (changed by this commit)
$(objtree) - the top of the kernel object tree
$(srctree) - the top of the kernel source tree
Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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There is an issue in clang's ThinLTO caching (enabled for the kernel via
'--thinlto-cache-dir') with .incbin, which the kernel occasionally uses
to include data within the kernel, such as the .config file for
/proc/config.gz. For example, when changing the .config and rebuilding
vmlinux, the copy of .config in vmlinux does not match the copy of
.config in the build folder:
$ echo 'CONFIG_LTO_NONE=n
CONFIG_LTO_CLANG_THIN=y
CONFIG_IKCONFIG=y
CONFIG_HEADERS_INSTALL=y' >kernel/configs/repro.config
$ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 clean defconfig repro.config vmlinux
...
$ grep CONFIG_HEADERS_INSTALL .config
CONFIG_HEADERS_INSTALL=y
$ scripts/extract-ikconfig vmlinux | grep CONFIG_HEADERS_INSTALL
CONFIG_HEADERS_INSTALL=y
$ scripts/config -d HEADERS_INSTALL
$ make -kj"$(nproc)" ARCH=x86_64 LLVM=1 vmlinux
...
UPD kernel/config_data
GZIP kernel/config_data.gz
CC kernel/configs.o
...
LD vmlinux
...
$ grep CONFIG_HEADERS_INSTALL .config
# CONFIG_HEADERS_INSTALL is not set
$ scripts/extract-ikconfig vmlinux | grep CONFIG_HEADERS_INSTALL
CONFIG_HEADERS_INSTALL=y
Without '--thinlto-cache-dir' or when using full LTO, this issue does
not occur.
Benchmarking incremental builds on a few different machines with and
without the cache shows a 20% increase in incremental build time without
the cache when measured by touching init/main.c and running 'make all'.
ARCH=arm64 defconfig + CONFIG_LTO_CLANG_THIN=y on an arm64 host:
Benchmark 1: With ThinLTO cache
Time (mean ± σ): 56.347 s ± 0.163 s [User: 83.768 s, System: 24.661 s]
Range (min … max): 56.109 s … 56.594 s 10 runs
Benchmark 2: Without ThinLTO cache
Time (mean ± σ): 67.740 s ± 0.479 s [User: 718.458 s, System: 31.797 s]
Range (min … max): 67.059 s … 68.556 s 10 runs
Summary
With ThinLTO cache ran
1.20 ± 0.01 times faster than Without ThinLTO cache
ARCH=x86_64 defconfig + CONFIG_LTO_CLANG_THIN=y on an x86_64 host:
Benchmark 1: With ThinLTO cache
Time (mean ± σ): 85.772 s ± 0.252 s [User: 91.505 s, System: 8.408 s]
Range (min … max): 85.447 s … 86.244 s 10 runs
Benchmark 2: Without ThinLTO cache
Time (mean ± σ): 103.833 s ± 0.288 s [User: 232.058 s, System: 8.569 s]
Range (min … max): 103.286 s … 104.124 s 10 runs
Summary
With ThinLTO cache ran
1.21 ± 0.00 times faster than Without ThinLTO cache
While it is unfortunate to take this performance improvement off the
table, correctness is more important. If/when this is fixed in LLVM, it
can potentially be brought back in a conditional manner. Alternatively,
a developer can just disable LTO if doing incremental compiles quickly
is important, as a full compile cycle can still take over a minute even
with the cache and it is unlikely that LTO will result in functional
differences for a kernel change.
Cc: stable@vger.kernel.org
Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO")
Reported-by: Yifan Hong <elsk@google.com>
Closes: https://github.com/ClangBuiltLinux/linux/issues/2021
Reported-by: Masami Hiramatsu <mhiramat@kernel.org>
Closes: https://lore.kernel.org/r/20220327115526.cc4b0ff55fc53c97683c3e4d@kernel.org/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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Running dtbs_check and dt_compatible_check targets really only depend
on processed-schema.json, but the dependency is 'dt_binding_check'. That
was sort worked around with the CHECK_DT_BINDING variable in order to
skip some of the work that 'dt_binding_check' does. It still runs the
full checks of the schemas which is not necessary and adds 10s of
seconds to the build time. That's significant when checking only a few
DTBs and with recent changes that have improved the validation time by
6-7x.
Add a new target, dt_binding_schema, which just builds
processed-schema.json and can be used as the dependency for other
targets. The scripts_dtc dependency isn't needed either as the examples
aren't built for it.
Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
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