164 Commits

Author SHA1 Message Date
Linus Torvalds
505d195b0f Merge tag 'char-misc-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc
Pull char/misc/IIO driver updates from Greg KH:
 "Here is the big set of char/misc/iio and other smaller driver
  subsystem changes for 7.0-rc1. Lots of little things in here,
  including:

   - Loads of iio driver changes and updates and additions

   - gpib driver updates

   - interconnect driver updates

   - i3c driver updates

   - hwtracing (coresight and intel) driver updates

   - deletion of the obsolete mwave driver

   - binder driver updates (rust and c versions)

   - mhi driver updates (causing a merge conflict, see below)

   - mei driver updates

   - fsi driver updates

   - eeprom driver updates

   - lots of other small char and misc driver updates and cleanups

  All of these have been in linux-next for a while, with no reported
  issues"

* tag 'char-misc-7.0-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (297 commits)
  mux: mmio: fix regmap leak on probe failure
  rust_binder: return p from rust_binder_transaction_target_node()
  drivers: android: binder: Update ARef imports from sync::aref
  rust_binder: fix needless borrow in context.rs
  iio: magn: mmc5633: Fix Kconfig for combination of I3C as module and driver builtin
  iio: sca3000: Fix a resource leak in sca3000_probe()
  iio: proximity: rfd77402: Add interrupt handling support
  iio: proximity: rfd77402: Document device private data structure
  iio: proximity: rfd77402: Use devm-managed mutex initialization
  iio: proximity: rfd77402: Use kernel helper for result polling
  iio: proximity: rfd77402: Align polling timeout with datasheet
  iio: cros_ec: Allow enabling/disabling calibration mode
  iio: frequency: ad9523: correct kernel-doc bad line warning
  iio: buffer: buffer_impl.h: fix kernel-doc warnings
  iio: gyro: itg3200: Fix unchecked return value in read_raw
  MAINTAINERS: add entry for ADE9000 driver
  iio: accel: sca3000: remove unused last_timestamp field
  iio: accel: adxl372: remove unused int2_bitmask field
  iio: adc: ad7766: Use iio_trigger_generic_data_rdy_poll()
  iio: magnetometer: Remove IRQF_ONESHOT
  ...
2026-02-17 09:11:04 -08:00
Linus Torvalds
0923fd0419 Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "Lock debugging:

   - Implement compiler-driven static analysis locking context checking,
     using the upcoming Clang 22 compiler's context analysis features
     (Marco Elver)

     We removed Sparse context analysis support, because prior to
     removal even a defconfig kernel produced 1,700+ context tracking
     Sparse warnings, the overwhelming majority of which are false
     positives. On an allmodconfig kernel the number of false positive
     context tracking Sparse warnings grows to over 5,200... On the plus
     side of the balance actual locking bugs found by Sparse context
     analysis is also rather ... sparse: I found only 3 such commits in
     the last 3 years. So the rate of false positives and the
     maintenance overhead is rather high and there appears to be no
     active policy in place to achieve a zero-warnings baseline to move
     the annotations & fixers to developers who introduce new code.

     Clang context analysis is more complete and more aggressive in
     trying to find bugs, at least in principle. Plus it has a different
     model to enabling it: it's enabled subsystem by subsystem, which
     results in zero warnings on all relevant kernel builds (as far as
     our testing managed to cover it). Which allowed us to enable it by
     default, similar to other compiler warnings, with the expectation
     that there are no warnings going forward. This enforces a
     zero-warnings baseline on clang-22+ builds (Which are still limited
     in distribution, admittedly)

     Hopefully the Clang approach can lead to a more maintainable
     zero-warnings status quo and policy, with more and more subsystems
     and drivers enabling the feature. Context tracking can be enabled
     for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
     disabled), but this will generate a lot of false positives.

     ( Having said that, Sparse support could still be added back,
       if anyone is interested - the removal patch is still
       relatively straightforward to revert at this stage. )

  Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)

    - Add support for Atomic<i8/i16/bool> and replace most Rust native
      AtomicBool usages with Atomic<bool>

    - Clean up LockClassKey and improve its documentation

    - Add missing Send and Sync trait implementation for SetOnce

    - Make ARef Unpin as it is supposed to be

    - Add __rust_helper to a few Rust helpers as a preparation for
      helper LTO

    - Inline various lock related functions to avoid additional function
      calls

  WW mutexes:

    - Extend ww_mutex tests and other test-ww_mutex updates (John
      Stultz)

  Misc fixes and cleanups:

    - rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
      Bergmann)

    - locking/local_lock: Include more missing headers (Peter Zijlstra)

    - seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)

    - rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
      Duberstein)"

* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
  locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
  rcu: Mark lockdep_assert_rcu_helper() __always_inline
  compiler-context-analysis: Remove __assume_ctx_lock from initializers
  tomoyo: Use scoped init guard
  crypto: Use scoped init guard
  kcov: Use scoped init guard
  compiler-context-analysis: Introduce scoped init guards
  cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
  seqlock: fix scoped_seqlock_read kernel-doc
  tools: Update context analysis macros in compiler_types.h
  rust: sync: Replace `kernel::c_str!` with C-Strings
  rust: sync: Inline various lock related methods
  rust: helpers: Move #define __rust_helper out of atomic.c
  rust: wait: Add __rust_helper to helpers
  rust: time: Add __rust_helper to helpers
  rust: task: Add __rust_helper to helpers
  rust: sync: Add __rust_helper to helpers
  rust: refcount: Add __rust_helper to helpers
  rust: rcu: Add __rust_helper to helpers
  rust: processor: Add __rust_helper to helpers
  ...
2026-02-10 12:28:44 -08:00
Miguel Ojeda
bd36f6e2ab rust: sync: atomic: Provide stub for rusttest 32-bit hosts
For arm32, on a x86_64 builder, running the `rusttest` target yields:

    error[E0080]: evaluation of constant value failed
      --> rust/kernel/static_assert.rs:37:23
       |
    37 |         const _: () = ::core::assert!($condition $(,$arg)?);
       |                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the evaluated program panicked at 'assertion failed: size_of::<isize>() == size_of::<isize_atomic_repr>()', rust/kernel/sync/atomic/predefine.rs:68:1
       |
      ::: rust/kernel/sync/atomic/predefine.rs:68:1
       |
    68 | static_assert!(size_of::<isize>() == size_of::<isize_atomic_repr>());
       | -------------------------------------------------------------------- in this macro invocation
       |
       = note: this error originates in the macro `::core::assert` which comes from the expansion of the macro `static_assert` (in Nightly builds, run with -Z macro-backtrace for more info)

The reason is that `rusttest` runs on the host, so for e.g. a x86_64
builder `isize` is 64 bits but it is not a `CONFIG_64BIT` build.

Fix it by providing a stub for `rusttest` as usual.

Fixes: 84c6d36bca ("rust: sync: atomic: Add Atomic<{usize,isize}>")
Cc: stable@vger.kernel.org
Reviewed-by: Onur Özkan <work@onurozkan.dev>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20260123233432.22703-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-01-26 02:18:58 +01:00
Alexandre Courbot
d6ff6e8700 rust: sync: refcount: always inline functions using build_assert with arguments
`build_assert` relies on the compiler to optimize out its error path.
Functions using it with its arguments must thus always be inlined,
otherwise the error path of `build_assert` might not be optimized out,
triggering a build error.

Cc: stable@vger.kernel.org
Fixes: bb38f35b35 ("rust: implement `kernel::sync::Refcount`")
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251208-io-build-assert-v3-5-98aded02c1ea@nvidia.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2026-01-18 20:40:12 +01:00
Alice Ryhl
ccf9e07011 rust: sync: Inline various lock related methods
While debugging a different issue [1], the following relocation was
noticed in the rust_binder.ko file:

	R_AARCH64_CALL26	_RNvXNtNtNtCsdfZWD8DztAw_6kernel4sync4lock8spinlockNtB2_15SpinLockBackendNtB4_7Backend6unlock

This relocation (and a similar one for lock) occurred many times
throughout the module. That is not really useful because all this
function does is call spin_unlock(), so what we actually want here is
that a call to spin_unlock() dirctly is generated in favor of this
wrapper method.

Thus, mark these methods inline.

[boqun: Reword the commit message a bit]

Link: https://lore.kernel.org/p/20251111-binder-fix-list-remove-v1-0-8ed14a0da63d@google.com
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251218-inline-lock-unlock-v2-1-fbadac8bd61b@google.com
2026-01-10 10:53:46 +08:00
FUJITA Tomonori
4bac28727a rust: sync: atomic: Add atomic bool tests
Add tests for Atomic<bool> operations.

Atomic<bool> does not fit into the existing u8/16/32/64 tests so
introduce a dedicated test for it.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20260101034922.2020334-3-fujita.tomonori@gmail.com
2026-01-09 19:01:41 +08:00
FUJITA Tomonori
06bd0e52bf rust: sync: atomic: Add atomic bool support via i8 representation
Add `bool` support, `Atomic<bool>` by using `i8` as its underlying
representation.

Rust specifies that `bool` has size 1 and alignment 1 [1], so it
matches `i8` on layout; keep `static_assert!()` checks to enforce this
assumption at build time.

[boqun: Remove the unnecessary impl AtomicImpl for bool]

Link: https://doc.rust-lang.org/reference/types/boolean.html [1]
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20260101034922.2020334-2-fujita.tomonori@gmail.com
2026-01-09 19:01:41 +08:00
FUJITA Tomonori
584f286f82 rust: sync: atomic: Add i8/i16 xchg and cmpxchg support
Add atomic xchg and cmpxchg operation support for i8 and i16 types
with tests.

Note that since the current implementation of
Atomic::<{i8,i16}>::{load,store}() is READ_ONCE()/WRITE_ONCE()-based.
The atomicity between load/store and xchg/cmpxchg is only guaranteed if
the architecture has native RmW support, hence i8/i16 is currently
AtomicImpl only when CONFIG_ARCH_SUPPORTS_ATOMIC_RWM=y.

[boqun: Make i8/i16 AtomicImpl only when
CONFIG_ARCH_SUPPORTS_ATOMIC_RWM=y]

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251228120546.1602275-4-fujita.tomonori@gmail.com
2026-01-09 19:01:41 +08:00
FUJITA Tomonori
7b001c97d9 rust: sync: atomic: Add store_release/load_acquire tests
Add minimum store_release/load_acquire tests.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251211113826.1299077-5-fujita.tomonori@gmail.com
2026-01-09 19:01:41 +08:00
FUJITA Tomonori
b33796d554 rust: sync: atomic: Add i8/i16 load and store support
Add atomic operation support for i8 and i16 types using volatile
read/write and smp_load_acquire/smp_store_release helpers.

[boqun: Adjust [1] to avoid introduction of
impl_atomic_only_load_and_store_ops!() in the middle]

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Joel Fernandes <joelagnelf@nvidia.com>
Link: https://lore.kernel.org/all/20251228120546.1602275-1-fujita.tomonori@gmail.com/ [1]
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251211113826.1299077-4-fujita.tomonori@gmail.com
2026-01-09 19:01:41 +08:00
FUJITA Tomonori
2bb8c41e61 rust: sync: atomic: Prepare AtomicOps macros for i8/i16 support
Rework the internal AtomicOps macro plumbing to generate per-type
implementations from a mapping list.

Capture the trait definition once and reuse it for both declaration
and per-type impl expansion to reduce duplication and keep future
extensions simple.

This is a preparatory refactor for enabling i8/i16 atomics cleanly.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251228120546.1602275-2-fujita.tomonori@gmail.com
2026-01-09 19:01:41 +08:00
Alice Ryhl
09248ed8cd rust: sync: Implement Unpin for ARef
The default implementation of Unpin for ARef<T> is conditional on T
being Unpin due to its PhantomData<T> field. However, this is overly
strict as pointers to T are legal to move even if T itself cannot move.

Since commit 66f1ea83d9 ("rust: lock: Add a Pin<&mut T> accessor")
this causes build failures when combined with a Mutex that contains an
field ARef<T>, because almost any type that ARef is used with is !Unpin.

Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251218-unpin-for-aref-v2-1-30d77129cbc6@google.com
2026-01-09 19:01:40 +08:00
FUJITA Tomonori
8a581130b1 rust: sync: set_once: Implement Send and Sync
Implement Send and Sync for SetOnce<T> to allow it to be used across
thread boundaries.

Send: SetOnce<T> can be transferred across threads when T: Send, as
the contained value is also transferred and will be dropped on the
destination thread.

Sync: SetOnce<T> can be shared across threads when T: Sync, as
as_ref() provides shared references &T and atomic operations ensure
proper synchronization. Since the inner T may be dropped on any
thread, we also require T: Send.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251216000901.221375-1-fujita.tomonori@gmail.com
2026-01-09 19:01:40 +08:00
Alice Ryhl
c1093b8589 rust: sync: add Arc::DATA_OFFSET
This constant will be used to expose some offset constants from the Rust
Binder driver to tracepoints which are implemented in C. The constant is
usually equal to sizeof(refcount_t), but may be larger if T has a large
alignment.

Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Daniel Almeida <daniel.almeida@collabora.com>
Link: https://patch.msgid.link/20251203-binder-trace1-v1-1-22d3ffddb44e@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-12-29 12:11:32 +01:00
Miguel Ojeda
309e49039f rust: sync: atomic: separate import "blocks"
Commit 14e9a18b07 ("rust: sync: atomic: Make Atomic*Ops pub(crate)")
added a `pub(crate)` import in the same "block" as the `pub` one,
without running `rustfmt`, which would sort them differently.

Instead of running `rustfmt` as-is, add a newline to keep the import
"blocks" with different visibilities separate.

Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2025-12-06 08:44:10 -08:00
Linus Torvalds
c84d574698 Merge tag 'modules-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux
Pull module updates from Daniel Gomez:
 "Rust module parameter support:

   - Add Rust module parameter support, enabling Rust kernel modules to
     declare and use module parameters. The rust_minimal sample module
     demonstrates this, and the rust null block driver will be the first
     to use it in the next cycle. This also adds the Rust module files
     under the modules subsystem as agreed between the Rust and modules
     maintainers.

  Hardening:

   - Add compile-time check for embedded NUL characters in MODULE_*()
     macros. This module metadata was once used (and maybe still) to
     bypass license enforcement (LWN article from 2003):

	https://lwn.net/Articles/82305/ [1]

  MAINTAINERS:

   - Add Aaron Tomlin as reviewer for the Modules subsystem"

* tag 'modules-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
  MAINTAINERS: Add myself as reviewer for module support
  module: Add compile-time check for embedded NUL characters
  media: radio: si470x: Fix DRIVER_AUTHOR macro definition
  media: dvb-usb-v2: lmedm04: Fix firmware macro definitions
  modules: add rust modules files to MAINTAINERS
  rust: samples: add a module parameter to the rust_minimal sample
  rust: module: update the module macro with module parameter support
  rust: module: use a reference in macros::module::module
  rust: introduce module_param module
  rust: str: add radix prefixed integer parsing functions
  rust: sync: add `SetOnce`
2025-12-06 08:27:07 -08:00
Linus Torvalds
784faa8eca Merge tag 'rust-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Add support for 'syn'.

     Syn is a parsing library for parsing a stream of Rust tokens into a
     syntax tree of Rust source code.

     Currently this library is geared toward use in Rust procedural
     macros, but contains some APIs that may be useful more generally.

     'syn' allows us to greatly simplify writing complex macros such as
     'pin-init' (Benno has already prepared the 'syn'-based version). We
     will use it in the 'macros' crate too.

     'syn' is the most downloaded Rust crate (according to crates.io),
     and it is also used by the Rust compiler itself. While the amount
     of code is substantial, there should not be many updates needed for
     these crates, and even if there are, they should not be too big,
     e.g. +7k -3k lines across the 3 crates in the last year.

     'syn' requires two smaller dependencies: 'quote' and 'proc-macro2'.
     I only modified their code to remove a third dependency
     ('unicode-ident') and to add the SPDX identifiers. The code can be
     easily verified to exactly match upstream with the provided
     scripts.

     They are all licensed under "Apache-2.0 OR MIT", like the other
     vendored 'alloc' crate we had for a while.

     Please see the merge commit with the cover letter for more context.

   - Allow 'unreachable_pub' and 'clippy::disallowed_names' for
     doctests.

     Examples (i.e. doctests) may want to do things like show public
     items and use names such as 'foo'.

     Nevertheless, we still try to keep examples as close to real code
     as possible (this is part of why running Clippy on doctests is
     important for us, e.g. for safety comments, which userspace Rust
     does not support yet but we are stricter).

  'kernel' crate:

   - Replace our custom 'CStr' type with 'core::ffi::CStr'.

     Using the standard library type reduces our custom code footprint,
     and we retain needed custom functionality through an extension
     trait and a new 'fmt!' macro which replaces the previous 'core'
     import.

     This started in 6.17 and continued in 6.18, and we finally land the
     replacement now. This required quite some stamina from Tamir, who
     split the changes in steps to prepare for the flag day change here.

   - Replace 'kernel::c_str!' with C string literals.

     C string literals were added in Rust 1.77, which produce '&CStr's
     (the 'core' one), so now we can write:

         c"hi"

     instead of:

         c_str!("hi")

   - Add 'num' module for numerical features.

     It includes the 'Integer' trait, implemented for all primitive
     integer types.

     It also includes the 'Bounded' integer wrapping type: an integer
     value that requires only the 'N' least significant bits of the
     wrapped type to be encoded:

         // An unsigned 8-bit integer, of which only the 4 LSBs are used.
         let v = Bounded::<u8, 4>::new::<15>();
         assert_eq!(v.get(), 15);

     'Bounded' is useful to e.g. enforce guarantees when working with
     bitfields that have an arbitrary number of bits.

     Values can also be constructed from simple non-constant expressions
     or, for more complex ones, validated at runtime.

     'Bounded' also comes with comparison and arithmetic operations
     (with both their backing type and other 'Bounded's with a
     compatible backing type), casts to change the backing type,
     extending/shrinking and infallible/fallible conversions from/to
     primitives as applicable.

   - 'rbtree' module: add immutable cursor ('Cursor').

     It enables to use just an immutable tree reference where
     appropriate. The existing fully-featured mutable cursor is renamed
     to 'CursorMut'.

  kallsyms:

   - Fix wrong "big" kernel symbol type read from procfs.

  'pin-init' crate:

   - A couple minor fixes (Benno asked me to pick these patches up for
     him this cycle).

  Documentation:

   - Quick Start guide: add Debian 13 (Trixie).

     Debian Stable is now able to build Linux, since Debian 13 (released
     2025-08-09) packages Rust 1.85.0, which is recent enough.

     We are planning to propose that the minimum supported Rust version
     in Linux follows Debian Stable releases, with Debian 13 being the
     first one we upgrade to, i.e. Rust 1.85.

  MAINTAINERS:

   - Add entry for the new 'num' module.

   - Remove Alex as Rust maintainer: he hasn't had the time to
     contribute for a few years now, so it is a no-op change in
     practice.

  And a few other cleanups and improvements"

* tag 'rust-6.19' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (53 commits)
  rust: macros: support `proc-macro2`, `quote` and `syn`
  rust: syn: enable support in kbuild
  rust: syn: add `README.md`
  rust: syn: remove `unicode-ident` dependency
  rust: syn: add SPDX License Identifiers
  rust: syn: import crate
  rust: quote: enable support in kbuild
  rust: quote: add `README.md`
  rust: quote: add SPDX License Identifiers
  rust: quote: import crate
  rust: proc-macro2: enable support in kbuild
  rust: proc-macro2: add `README.md`
  rust: proc-macro2: remove `unicode_ident` dependency
  rust: proc-macro2: add SPDX License Identifiers
  rust: proc-macro2: import crate
  rust: kbuild: support using libraries in `rustc_procmacro`
  rust: kbuild: support skipping flags in `rustc_test_library`
  rust: kbuild: add proc macro library support
  rust: kbuild: simplify `--cfg` handling
  rust: kbuild: introduce `core-flags` and `core-skip_flags`
  ...
2025-12-03 14:16:49 -08:00
Linus Torvalds
b53440f8e5 Merge tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "Mutexes:

   - Redo __mutex_init() to reduce generated code size (Sebastian
     Andrzej Siewior)

  Seqlocks:

   - Introduce scoped_seqlock_read() (Peter Zijlstra)

   - Change thread_group_cputime() to use scoped_seqlock_read() (Oleg
     Nesterov)

   - Change do_task_stat() to use scoped_seqlock_read() (Oleg Nesterov)

   - Change do_io_accounting() to use scoped_seqlock_read() (Oleg
     Nesterov)

   - Fix the incorrect documentation of read_seqbegin_or_lock() /
     need_seqretry() (Oleg Nesterov)

   - Allow KASAN to fail optimizing (Peter Zijlstra)

  Local lock updates:

   - Fix all kernel-doc warnings (Randy Dunlap)

   - Add the <linux/local_lock*.h> headers to MAINTAINERS (Sebastian
     Andrzej Siewior)

   - Reduce the risk of shadowing via s/l/__l/ and s/tl/__tl/ (Vincent
     Mailhol)

  Lock debugging:

   - spinlock/debug: Fix data-race in do_raw_write_lock (Alexander
     Sverdlin)

  Atomic primitives infrastructure:

   - atomic: Skip alignment check for try_cmpxchg() old arg (Arnd
     Bergmann)

  Rust runtime integration:

   - sync: atomic: Enable generated Atomic<T> usage (Boqun Feng)

   - sync: atomic: Implement Debug for Atomic<Debug> (Boqun Feng)

   - debugfs: Remove Rust native atomics and replace them with Linux
     versions (Boqun Feng)

   - debugfs: Implement Reader for Mutex<T> only when T is Unpin (Boqun
     Feng)

   - lock: guard: Add T: Unpin bound to DerefMut (Daniel Almeida)

   - lock: Pin the inner data (Daniel Almeida)

   - lock: Add a Pin<&mut T> accessor (Daniel Almeida)"

* tag 'locking-core-2025-12-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/local_lock: Fix all kernel-doc warnings
  locking/local_lock: s/l/__l/ and s/tl/__tl/ to reduce the risk of shadowing
  locking/local_lock: Add the <linux/local_lock*.h> headers to MAINTAINERS
  locking/mutex: Redo __mutex_init() to reduce generated code size
  rust: debugfs: Replace the usage of Rust native atomics
  rust: sync: atomic: Implement Debug for Atomic<Debug>
  rust: sync: atomic: Make Atomic*Ops pub(crate)
  seqlock: Allow KASAN to fail optimizing
  rust: debugfs: Implement Reader for Mutex<T> only when T is Unpin
  seqlock: Change do_io_accounting() to use scoped_seqlock_read()
  seqlock: Change do_task_stat() to use scoped_seqlock_read()
  seqlock: Change thread_group_cputime() to use scoped_seqlock_read()
  seqlock: Introduce scoped_seqlock_read()
  documentation: seqlock: fix the wrong documentation of read_seqbegin_or_lock/need_seqretry
  atomic: Skip alignment check for try_cmpxchg() old arg
  rust: lock: Add a Pin<&mut T> accessor
  rust: lock: Pin the inner data
  rust: lock: guard: Add T: Unpin bound to DerefMut
  locking/spinlock/debug: Fix data-race in do_raw_write_lock
2025-12-01 19:50:58 -08:00
Boqun Feng
013f912eb5 rust: sync: atomic: Implement Debug for Atomic<Debug>
If `Atomic<T>` is `Debug` then it's a `debugfs::Writer`, therefore make
it so since 1) debugfs needs to support `Atomic<T>` and 2) it's rather
trivial to implement `Debug` for `Atomic<Debug>`.

Tested-by: David Gow <davidgow@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251022035324.70785-3-boqun.feng@gmail.com
2025-11-12 08:56:41 -08:00
Boqun Feng
14e9a18b07 rust: sync: atomic: Make Atomic*Ops pub(crate)
In order to write code over a generate Atomic<T> we need to make
Atomic*Ops public so that functions like `.load()` and `.store()` are
available. Make these pub(crate) at the beginning so the usage in kernel
crate is supported.

Tested-by: David Gow <davidgow@google.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20251022035324.70785-2-boqun.feng@gmail.com
2025-11-12 08:56:38 -08:00
Andreas Hindborg
821fe7bf16 rust: sync: add SetOnce
Introduce the `SetOnce` type, a container that can only be written once.
The container uses an internal atomic to synchronize writes to the internal
value.

Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Tested-by: Daniel Gomez <da.gomez@samsung.com>
Signed-off-by: Daniel Gomez <da.gomez@kernel.org>
2025-11-03 14:40:35 +01:00
Miguel Ojeda
09b1704f5b rust: condvar: fix broken intra-doc link
The future move of pin-init to `syn` uncovers the following broken
intra-doc link:

    error: unresolved link to `crate::pin_init`
      --> rust/kernel/sync/condvar.rs:39:40
       |
    39 | /// instances is with the [`pin_init`](crate::pin_init!) and [`new_condvar`] macros.
       |                                        ^^^^^^^^^^^^^^^^ no item named `pin_init` in module `kernel`
       |
       = note: `-D rustdoc::broken-intra-doc-links` implied by `-D warnings`
       = help: to override `-D warnings` add `#[allow(rustdoc::broken_intra_doc_links)]`

Currently, when rendered, the link points to a literal `crate::pin_init!`
URL.

Thus fix it.

Cc: stable@vger.kernel.org
Fixes: 129e97be8e ("rust: pin-init: fix documentation links")
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patch.msgid.link/20251029073344.349341-1-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-11-02 23:18:42 +01:00
Tamir Duberstein
3b83f5d5e7 rust: replace CStr with core::ffi::CStr
`kernel::ffi::CStr` was introduced in commit d126d23801 ("rust: str:
add `CStr` type") in November 2022 as an upstreaming of earlier work
that was done in May 2021[0]. That earlier work, having predated the
inclusion of `CStr` in `core`, largely duplicated the implementation of
`std::ffi::CStr`.

`std::ffi::CStr` was moved to `core::ffi::CStr` in Rust 1.64 in
September 2022. Hence replace `kernel::str::CStr` with `core::ffi::CStr`
to reduce our custom code footprint, and retain needed custom
functionality through an extension trait.

Add `CStr` to `ffi` and the kernel prelude.

Link: faa3cbcca0 [0]
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Link: https://patch.msgid.link/20251018-cstr-core-v18-16-9378a54385f8@gmail.com
[ Removed assert that would now depend on the Rust version. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-10-22 07:47:27 +02:00
Daniel Almeida
66f1ea83d9 rust: lock: Add a Pin<&mut T> accessor
In order for callers to be able to access the inner T safely if T:
!Unpin, there needs to be a way to get a Pin<&mut T>. Add this accessor
and a corresponding example to tell users how it works.

This requires the pin projection functionality [1] for better ergonomic.

[boqun: Apply Daniel's fix to the code example, add the reference to pin
projection patch and remove out-of-date part in the commit log]

Suggested-by: Benno Lossin <lossin@kernel.org>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1181
Link: https://lore.kernel.org/rust-for-linux/20250912174148.373530-1-lossin@kernel.org/ [1]
2025-10-21 12:31:56 +02:00
Daniel Almeida
2497a7116f rust: lock: Pin the inner data
In preparation to support Lock<T> where T is pinned, the first thing
that needs to be done is to structurally pin the 'data' member. This
switches the 't' parameter in Lock<T>::new() to take in an impl
PinInit<T> instead of a plain T. This in turn uses the blanket
implementation "impl PinInit<T> for T".

Subsequent patches will touch on Guard<T>.

Suggested-by: Benno Lossin <lossin@kernel.org>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1181
2025-10-21 12:31:55 +02:00
Daniel Almeida
da123f0ee4 rust: lock: guard: Add T: Unpin bound to DerefMut
A core property of pinned types is not handing a mutable reference to
the inner data in safe code, as this trivially allows that data to be
moved.

Enforce this condition by adding a bound on lock::Guard's DerefMut
implementation, so that it's only implemented for pinning-agnostic
types.

Suggested-by: Benno Lossin <lossin@kernel.org>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Daniel Almeida <daniel.almeida@collabora.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://github.com/Rust-for-Linux/linux/issues/1181
2025-10-21 12:31:55 +02:00
Linus Torvalds
f4e0ff7e45 Merge tag 'rust-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Derive 'Zeroable' for all structs and unions generated by 'bindgen'
     where possible and corresponding cleanups. To do so, add the
     'pin-init' crate as a dependency to 'bindings' and 'uapi'.

     It also includes its first use in the 'cpufreq' module, with more
     to come in the next cycle.

   - Add warning to the 'rustdoc' target to detect broken 'srctree/'
     links and fix existing cases.

   - Remove support for unused (since v6.16) host '#[test]'s,
     simplifying the 'rusttest' target. Tests should generally run
     within KUnit.

  'kernel' crate:

   - Add 'ptr' module with a new 'Alignment' type, which is always a
     power of two and is used to validate that a given value is a valid
     alignment and to perform masking and alignment operations:

         // Checked at build time.
         assert_eq!(Alignment::new::<16>().as_usize(), 16);

         // Checked at runtime.
         assert_eq!(Alignment::new_checked(15), None);

         assert_eq!(Alignment::of::<u8>().log2(), 0);

         assert_eq!(0x25u8.align_down(Alignment::new::<0x10>()), 0x20);
         assert_eq!(0x5u8.align_up(Alignment::new::<0x10>()), Some(0x10));
         assert_eq!(u8::MAX.align_up(Alignment::new::<0x10>()), None);

     It also includes its first use in Nova.

   - Add 'core::mem::{align,size}_of{,_val}' to the prelude, matching
     Rust 1.80.0.

   - Keep going with the steps on our migration to the standard library
     'core::ffi::CStr' type (use 'kernel::{fmt, prelude::fmt!}' and use
     upstream method names).

   - 'error' module: improve 'Error::from_errno' and 'to_result'
     documentation, including examples/tests.

   - 'sync' module: extend 'aref' submodule documentation now that it
     exists, and more updates to complete the ongoing move of 'ARef' and
     'AlwaysRefCounted' to 'sync::aref'.

   - 'list' module: add an example/test for 'ListLinksSelfPtr' usage.

   - 'alloc' module:

      - Implement 'Box::pin_slice()', which constructs a pinned slice of
        elements.

      - Provide information about the minimum alignment guarantees of
        'Kmalloc', 'Vmalloc' and 'KVmalloc'.

      - Take minimum alignment guarantees of allocators for
        'ForeignOwnable' into account.

      - Remove the 'allocator_test' (including 'Cmalloc').

      - Add doctest for 'Vec::as_slice()'.

      - Constify various methods.

   - 'time' module:

      - Add methods on 'HrTimer' that can only be called with exclusive
        access to an unarmed timer, or from timer callback context.

      - Add arithmetic operations to 'Instant' and 'Delta'.

      - Add a few convenience and access methods to 'HrTimer' and
        'Instant'.

  'macros' crate:

   - Reduce collections in 'quote!' macro.

  And a few other cleanups and improvements"

* tag 'rust-6.18' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (58 commits)
  gpu: nova-core: use Alignment for alignment-related operations
  rust: add `Alignment` type
  rust: macros: reduce collections in `quote!` macro
  rust: acpi: use `core::ffi::CStr` method names
  rust: of: use `core::ffi::CStr` method names
  rust: net: use `core::ffi::CStr` method names
  rust: miscdevice: use `core::ffi::CStr` method names
  rust: kunit: use `core::ffi::CStr` method names
  rust: firmware: use `core::ffi::CStr` method names
  rust: drm: use `core::ffi::CStr` method names
  rust: cpufreq: use `core::ffi::CStr` method names
  rust: configfs: use `core::ffi::CStr` method names
  rust: auxiliary: use `core::ffi::CStr` method names
  drm/panic: use `core::ffi::CStr` method names
  rust: device: use `kernel::{fmt,prelude::fmt!}`
  rust: sync: use `kernel::{fmt,prelude::fmt!}`
  rust: seq_file: use `kernel::{fmt,prelude::fmt!}`
  rust: kunit: use `kernel::{fmt,prelude::fmt!}`
  rust: file: use `kernel::{fmt,prelude::fmt!}`
  rust: device: use `kernel::{fmt,prelude::fmt!}`
  ...
2025-09-30 19:12:49 -07:00
Tamir Duberstein
0fe1ca3c8b rust: sync: use kernel::{fmt,prelude::fmt!}
Reduce coupling to implementation details of the formatting machinery by
avoiding direct use for `core`'s formatting traits and macros.

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-09-16 09:26:59 +02:00
Gary Guo
a307bf1db5 rust: block: convert block::mq to use Refcount
Currently there's a custom reference counting in `block::mq`, which uses
`AtomicU64` Rust atomics, and this type doesn't exist on some 32-bit
architectures. We cannot just change it to use 32-bit atomics, because
doing so will make it vulnerable to refcount overflow. So switch it to
use the kernel refcount `kernel::sync::Refcount` instead.

There is an operation needed by `block::mq`, atomically decreasing
refcount from 2 to 0, which is not available through refcount.h, so
I exposed `Refcount::as_atomic` which allows accessing the refcount
directly.

[boqun: Adopt the LKMM atomic API]
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Tested-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/r/20250723233312.3304339-5-gary@kernel.org
2025-09-15 09:38:36 +02:00
Gary Guo
076acb647c rust: convert Arc to use Refcount
With `Refcount` type created, `Arc` can use `Refcount` instead of
calling into FFI directly.

Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/r/20250723233312.3304339-4-gary@kernel.org
2025-09-15 09:38:35 +02:00
Gary Guo
7487645f0b rust: make Arc::into_unique_or_drop associated function
Make `Arc::into_unique_or_drop` to become a mere associated function
instead of a method (i.e. removing the `self` receiver).

It's a general convention for Rust smart pointers to avoid having
methods defined on them, because if the pointee type has a method of the
same name, then it is shadowed. This is normally for avoiding semver
breakage, which isn't an issue for kernel codebase, but it's still
generally a good practice to follow this rule, so that `ptr.foo()` would
always be calling a method on the pointee type.

Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/r/20250723233312.3304339-3-gary@kernel.org
2025-09-15 09:38:35 +02:00
Gary Guo
bb38f35b35 rust: implement kernel::sync::Refcount
This is a wrapping layer of `include/linux/refcount.h`. Currently the
kernel refcount has already been used in `Arc`, however it calls into
FFI directly.

[boqun: Add the missing <> for the link in comment]
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Fiona Behrens <me@kloenk.dev>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/r/20250723233312.3304339-2-gary@kernel.org
2025-09-15 09:38:35 +02:00
Boqun Feng
d9ea5a41ce rust: sync: Add memory barriers
Memory barriers are building blocks for concurrent code, hence provide
a minimal set of them.

The compiler barrier, barrier(), is implemented in inline asm instead of
using core::sync::atomic::compiler_fence() because memory models are
different: kernel's atomics are implemented in inline asm therefore the
compiler barrier should be implemented in inline asm as well. Also it's
currently only public to the kernel crate until there's a reasonable
driver usage.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-10-boqun.feng@gmail.com/
2025-09-15 09:38:34 +02:00
Boqun Feng
84c6d36bca rust: sync: atomic: Add Atomic<{usize,isize}>
Add generic atomic support for `usize` and `isize`. Note that instead of
mapping directly to `atomic_long_t`, the represention type
(`AtomicType::Repr`) is selected based on CONFIG_64BIT. This reduces
the necessity of creating `atomic_long_*` helpers, which could save
the binary size of kernel if inline helpers are not available. To do so,
an internal type `isize_atomic_repr` is defined, it's `i32` in 32bit
kernel and `i64` in 64bit kernel.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-9-boqun.feng@gmail.com/
2025-09-15 09:38:34 +02:00
Boqun Feng
d6df37ba91 rust: sync: atomic: Add Atomic<u{32,64}>
Add generic atomic support for basic unsigned types that have an
`AtomicImpl` with the same size and alignment.

Unit tests are added including Atomic<i32> and Atomic<i64>.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-8-boqun.feng@gmail.com/
2025-09-15 09:38:34 +02:00
Boqun Feng
d132054360 rust: sync: atomic: Add the framework of arithmetic operations
One important set of atomic operations is the arithmetic operations,
i.e. add(), sub(), fetch_add(), add_return(), etc. However it may not
make senses for all the types that `AtomicType` to have arithmetic
operations, for example a `Foo(u32)` may not have a reasonable add() or
sub(), plus subword types (`u8` and `u16`) currently don't have
atomic arithmetic operations even on C side and might not have them in
the future in Rust (because they are usually suboptimal on a few
architecures). Therefore the plan is to add a few subtraits of
`AtomicType` describing which types have and can do atomic arithemtic
operations.

One trait `AtomicAdd` is added, and only add() and fetch_add() are
added. The rest will be added in the future.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-7-boqun.feng@gmail.com/
2025-09-15 09:38:34 +02:00
Boqun Feng
b606a532c0 rust: sync: atomic: Add atomic {cmp,}xchg operations
xchg() and cmpxchg() are basic operations on atomic. Provide these based
on C APIs.

Note that cmpxchg() use the similar function signature as
compare_exchange() in Rust std: returning a `Result`, `Ok(old)` means
the operation succeeds and `Err(old)` means the operation fails.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-6-boqun.feng@gmail.com/
2025-09-15 09:38:33 +02:00
Boqun Feng
29c32c405e rust: sync: atomic: Add generic atomics
To provide using LKMM atomics for Rust code, a generic `Atomic<T>` is
added, currently `T` needs to be Send + Copy because these are the
straightforward usages and all basic types support this.

Implement `AtomicType` for `i32` and `i64`, and so far only basic
operations load() and store() are introduced.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-5-boqun.feng@gmail.com/
2025-09-15 09:38:33 +02:00
Boqun Feng
b638c9bc47 rust: sync: atomic: Add ordering annotation types
Preparation for atomic primitives. Instead of a suffix like _acquire, a
method parameter along with the corresponding generic parameter will be
used to specify the ordering of an atomic operations. For example,
atomic load() can be defined as:

	impl<T: ...> Atomic<T> {
	    pub fn load<O: AcquireOrRelaxed>(&self, _o: O) -> T { ... }
	}

and acquire users would do:

	let r = x.load(Acquire);

relaxed users:

	let r = x.load(Relaxed);

doing the following:

	let r = x.load(Release);

will cause a compiler error.

Compared to suffixes, it's easier to tell what ordering variants an
operation has, and it also make it easier to unify the implementation of
all ordering variants in one method via generic. The `TYPE` associate
const is for generic function to pick up the particular implementation
specified by an ordering annotation.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-4-boqun.feng@gmail.com/
2025-09-15 09:38:33 +02:00
Boqun Feng
2387fb2a9b rust: sync: Add basic atomic operation mapping framework
Preparation for generic atomic implementation. To unify the
implementation of a generic method over `i32` and `i64`, the C side
atomic methods need to be grouped so that in a generic method, they can
be referred as <type>::<method>, otherwise their parameters and return
value are different between `i32` and `i64`, which would require using
`transmute()` to unify the type into a `T`.

Introduce `AtomicImpl` to represent a basic type in Rust that has the
direct mapping to an atomic implementation from C. Use a sealed trait to
restrict `AtomicImpl` to only support `i32` and `i64` for now.

Further, different methods are put into different `*Ops` trait groups,
and this is for the future when smaller types like `i8`/`i16` are
supported but only with a limited set of API (e.g. only set(), load(),
xchg() and cmpxchg(), no add() or sub() etc).

While the atomic mod is introduced, documentation is also added for
memory models and data races.

Also bump my role to the maintainer of ATOMIC INFRASTRUCTURE to reflect
my responsibility on the Rust atomic mod.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Elle Rhumsaa <elle@weathered-steel.dev>
Link: https://lore.kernel.org/all/20250719030827.61357-3-boqun.feng@gmail.com/
2025-09-15 09:38:32 +02:00
Benno Lossin
a15d12c24f rust: sync: extend module documentation of aref
Commit 07dad44aa9 ("rust: kernel: move ARef and AlwaysRefCounted to
sync::aref") moved `ARef` and `AlwaysRefCounted` into their own module.
In that process only a short, single line description of the module was
added. Extend the description by explaining what is meant by "internal
reference counting", the two items in the trait & the difference to
`Arc`.

Signed-off-by: Benno Lossin <lossin@kernel.org>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-09-15 00:02:22 +02:00
Shankari Anand
8a7c11af8e rust: sync: Update ARef and AlwaysRefCounted imports from sync::aref
Update the in-file reference of sync/aref.rs to import `ARef` and
`AlwaysRefCounted` from `sync::aref` instead of `types`.

This aligns with the ongoing effort to move `ARef` and
`AlwaysRefCounted` to sync.

Suggested-by: Benno Lossin <lossin@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1173
Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-09-08 00:11:19 +02:00
Alice Ryhl
bb9749f32a rust: alloc: take the allocator into account for FOREIGN_ALIGN
When converting a Box<T> into a void pointer, the allocator might
guarantee a higher alignment than the type itself does, and in that case
it is guaranteed that the void pointer has that higher alignment.

This is quite useful when combined with the XArray, which you can only
create using a ForeignOwnable whose FOREIGN_ALIGN is at least 4. This
means that you can now always use a Box<T> with the XArray no matter the
alignment of T.

Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Link: https://lore.kernel.org/r/20250811-align-min-allocator-v2-2-3386cc94f4fc@google.com
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
2025-08-15 20:55:16 +02:00
Linus Torvalds
352af6a011 Merge tag 'rust-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux
Pull Rust updates from Miguel Ojeda:
 "Toolchain and infrastructure:

   - Enable a set of Clippy lints: 'ptr_as_ptr', 'ptr_cast_constness',
     'as_ptr_cast_mut', 'as_underscore', 'cast_lossless' and
     'ref_as_ptr'

     These are intended to avoid type casts with the 'as' operator,
     which are quite powerful, into restricted variants that are less
     powerful and thus should help to avoid mistakes

   - Remove the 'author' key now that most instances were moved to the
     plural one in the previous cycle

  'kernel' crate:

   - New 'bug' module: add 'warn_on!' macro which reuses the existing
     'BUG'/'WARN' infrastructure, i.e. it respects the usual sysctls and
     kernel parameters:

         warn_on!(value == 42);

     To avoid duplicating the assembly code, the same strategy is
     followed as for the static branch code in order to share the
     assembly between both C and Rust

     This required a few rearrangements on C arch headers -- the
     existing C macros should still generate the same outputs, thus no
     functional change expected there

   - 'workqueue' module: add delayed work items, including a
     'DelayedWork' struct, a 'impl_has_delayed_work!' macro and an
     'enqueue_delayed' method, e.g.:

         /// Enqueue the struct for execution on the system workqueue,
         /// where its value will be printed 42 jiffies later.
         fn print_later(value: Arc<MyStruct>) {
             let _ = workqueue::system().enqueue_delayed(value, 42);
         }

   - New 'bits' module: add support for 'bit' and 'genmask' functions,
     with runtime- and compile-time variants, e.g.:

         static_assert!(0b00010000 == bit_u8(4));
         static_assert!(0b00011110 == genmask_u8(1..=4));

         assert!(checked_bit_u32(u32::BITS).is_none());

   - 'uaccess' module: add 'UserSliceReader::strcpy_into_buf', which
     reads NUL-terminated strings from userspace into a '&CStr'

     Introduce 'UserPtr' newtype, similar in purpose to '__user' in C,
     to minimize mistakes handling userspace pointers, including mixing
     them up with integers and leaking them via the 'Debug' trait. Add
     it to the prelude, too

   - Start preparations for the replacement of our custom 'CStr' type
     with the analogous type in the 'core' standard library. This will
     take place across several cycles to make it easier. For this one,
     it includes a new 'fmt' module, using upstream method names and
     some other cleanups

     Replace 'fmt!' with a re-export, which helps Clippy lint properly,
     and clean up the found 'uninlined-format-args' instances

   - 'dma' module:

      - Clarify wording and be consistent in 'coherent' nomenclature

      - Convert the 'read!()' and 'write!()' macros to return a 'Result'

      - Add 'as_slice()', 'write()' methods in 'CoherentAllocation'

      - Expose 'count()' and 'size()' in 'CoherentAllocation' and add
        the corresponding type invariants

      - Implement 'CoherentAllocation::dma_handle_with_offset()'

   - 'time' module:

      - Make 'Instant' generic over clock source. This allows the
        compiler to assert that arithmetic expressions involving the
        'Instant' use 'Instants' based on the same clock source

      - Make 'HrTimer' generic over the timer mode. 'HrTimer' timers
        take a 'Duration' or an 'Instant' when setting the expiry time,
        depending on the timer mode. With this change, the compiler can
        check the type matches the timer mode

      - Add an abstraction for 'fsleep'. 'fsleep' is a flexible sleep
        function that will select an appropriate sleep method depending
        on the requested sleep time

      - Avoid 64-bit divisions on 32-bit hardware when calculating
        timestamps

      - Seal the 'HrTimerMode' trait. This prevents users of the
        'HrTimerMode' from implementing the trait on their own types

      - Pass the correct timer mode ID to 'hrtimer_start_range_ns()'

   - 'list' module: remove 'OFFSET' constants, allowing to remove
     pointer arithmetic; now 'impl_list_item!' invokes
     'impl_has_list_links!' or 'impl_has_list_links_self_ptr!'. Other
     simplifications too

   - 'types' module: remove 'ForeignOwnable::PointedTo' in favor of a
     constant, which avoids exposing the type of the opaque pointer, and
     require 'into_foreign' to return non-null

     Remove the 'Either<L, R>' type as well. It is unused, and we want
     to encourage the use of custom enums for concrete use cases

   - 'sync' module: implement 'Borrow' and 'BorrowMut' for 'Arc' types
     to allow them to be used in generic APIs

   - 'alloc' module: implement 'Borrow' and 'BorrowMut' for 'Box<T, A>';
     and 'Borrow', 'BorrowMut' and 'Default' for 'Vec<T, A>'

   - 'Opaque' type: add 'cast_from' method to perform a restricted cast
     that cannot change the inner type and use it in callers of
     'container_of!'. Rename 'raw_get' to 'cast_into' to match it

   - 'rbtree' module: add 'is_empty' method

   - 'sync' module: new 'aref' submodule to hold 'AlwaysRefCounted' and
     'ARef', which are moved from the too general 'types' module which
     we want to reduce or eventually remove. Also fix a safety comment
     in 'static_lock_class'

  'pin-init' crate:

   - Add 'impl<T, E> [Pin]Init<T, E> for Result<T, E>', so results are
     now (pin-)initializers

   - Add 'Zeroable::init_zeroed()' that delegates to 'init_zeroed()'

   - New 'zeroed()', a safe version of 'mem::zeroed()' and also provide
     it via 'Zeroable::zeroed()'

   - Implement 'Zeroable' for 'Option<&T>', 'Option<&mut T>' and for
     'Option<[unsafe] [extern "abi"] fn(...args...) -> ret>' for
     '"Rust"' and '"C"' ABIs and up to 20 arguments

   - Changed blanket impls of 'Init' and 'PinInit' from 'impl<T, E>
     [Pin]Init<T, E> for T' to 'impl<T> [Pin]Init<T> for T'

   - Renamed 'zeroed()' to 'init_zeroed()'

   - Upstream dev news: improve CI more to deny warnings, use
     '--all-targets'. Check the synchronization status of the two
     '-next' branches in upstream and the kernel

  MAINTAINERS:

   - Add Vlastimil Babka, Liam R. Howlett, Uladzislau Rezki and Lorenzo
     Stoakes as reviewers (thanks everyone)

  And a few other cleanups and improvements"

* tag 'rust-6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (76 commits)
  rust: Add warn_on macro
  arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
  rust: kernel: move ARef and AlwaysRefCounted to sync::aref
  rust: sync: fix safety comment for `static_lock_class`
  rust: types: remove `Either<L, R>`
  rust: kernel: use `core::ffi::CStr` method names
  rust: str: add `CStr` methods matching `core::ffi::CStr`
  rust: str: remove unnecessary qualification
  rust: use `kernel::{fmt,prelude::fmt!}`
  rust: kernel: add `fmt` module
  rust: kernel: remove `fmt!`, fix clippy::uninlined-format-args
  scripts: rust: emit path candidates in panic message
  scripts: rust: replace length checks with match
  rust: list: remove nonexistent generic parameter in link
  rust: bits: add support for bits/genmask macros
  rust: list: remove OFFSET constants
  rust: list: add `impl_list_item!` examples
  rust: list: use fully qualified path
  ...
2025-08-03 13:49:10 -07:00
Linus Torvalds
72b8944f14 Merge tag 'locking-core-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "Locking primitives:

   - Mark devm_mutex_init() as __must_check and fix drivers that didn't
     check the return code (Thomas Weißschuh)

   - Reorganize <linux/local_lock.h> to better expose the internal APIs
     to local variables (Sebastian Andrzej Siewior)

   - Remove OWNER_SPINNABLE in rwsem (Jinliang Zheng)

   - Remove redundant #ifdefs in the mutex code (Ran Xiaokai)

  Lockdep:

   - Avoid returning struct in lock_stats() (Arnd Bergmann)

   - Change `static const` into enum for LOCKF_*_IRQ_* (Arnd Bergmann)

   - Temporarily use synchronize_rcu_expedited() in
     lockdep_unregister_key() to speed things up. (Breno Leitao)

  Rust runtime:

   - Add #[must_use] to Lock::try_lock() (Jason Devers)"

* tag 'locking-core-2025-07-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  lockdep: Speed up lockdep_unregister_key() with expedited RCU synchronization
  locking/mutex: Remove redundant #ifdefs
  locking/lockdep: Change 'static const' variables to enum values
  locking/lockdep: Avoid struct return in lock_stats()
  locking/rwsem: Use OWNER_NONSPINNABLE directly instead of OWNER_SPINNABLE
  rust: sync: Add #[must_use] to Lock::try_lock()
  locking/mutex: Mark devm_mutex_init() as __must_check
  leds: lp8860: Check return value of devm_mutex_init()
  spi: spi-nxp-fspi: Check return value of devm_mutex_init()
  local_lock: Move this_cpu_ptr() notation from internal to main header
2025-07-29 18:11:32 -07:00
Linus Torvalds
bf76f23aa1 Merge tag 'sched-core-2025-07-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
 "Core scheduler changes:

   - Better tracking of maximum lag of tasks in presence of different
     slices duration, for better handling of lag in the fair scheduler
     (Vincent Guittot)

   - Clean up and standardize #if/#else/#endif markers throughout the
     entire scheduler code base (Ingo Molnar)

   - Make SMP unconditional: build the SMP scheduler's data structures
     and logic on UP kernel too, even though they are not used, to
     simplify the scheduler and remove around 200 #ifdef/[#else]/#endif
     blocks from the scheduler (Ingo Molnar)

   - Reorganize cgroup bandwidth control interface handling for better
     interfacing with sched_ext (Tejun Heo)

  Balancing:

   - Bump sd->max_newidle_lb_cost when newidle balance fails (Chris
     Mason)

   - Remove sched_domain_topology_level::flags to simplify the code
     (Prateek Nayak)

   - Simplify and clean up build_sched_topology() (Li Chen)

   - Optimize build_sched_topology() on large machines (Li Chen)

  Real-time scheduling:

   - Add initial version of proxy execution: a mechanism for
     mutex-owning tasks to inherit the scheduling context of higher
     priority waiters.

     Currently limited to a single runqueue and conditional on
     CONFIG_EXPERT, and other limitations (John Stultz, Peter Zijlstra,
     Valentin Schneider)

   - Deadline scheduler (Juri Lelli):
      - Fix dl_servers initialization order (Juri Lelli)
      - Fix DL scheduler's root domain reinitialization logic (Juri
        Lelli)
      - Fix accounting bugs after global limits change (Juri Lelli)
      - Fix scalability regression by implementing less agressive
        dl_server handling (Peter Zijlstra)

  PSI:

   - Improve scalability by optimizing psi_group_change() cpu_clock()
     usage (Peter Zijlstra)

  Rust changes:

   - Make Task, CondVar and PollCondVar methods inline to avoid
     unnecessary function calls (Kunwu Chan, Panagiotis Foliadis)

   - Add might_sleep() support for Rust code: Rust's "#[track_caller]"
     mechanism is used so that Rust's might_sleep() doesn't need to be
     defined as a macro (Fujita Tomonori)

   - Introduce file_from_location() (Boqun Feng)

  Debugging & instrumentation:

   - Make clangd usable with scheduler source code files again (Peter
     Zijlstra)

   - tools: Add root_domains_dump.py which dumps root domains info (Juri
     Lelli)

   - tools: Add dl_bw_dump.py for printing bandwidth accounting info
     (Juri Lelli)

  Misc cleanups & fixes:

   - Remove play_idle() (Feng Lee)

   - Fix check_preemption_disabled() (Sebastian Andrzej Siewior)

   - Do not call __put_task_struct() on RT if pi_blocked_on is set (Luis
     Claudio R. Goncalves)

   - Correct the comment in place_entity() (wang wei)"

* tag 'sched-core-2025-07-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (84 commits)
  sched/idle: Remove play_idle()
  sched: Do not call __put_task_struct() on rt if pi_blocked_on is set
  sched: Start blocked_on chain processing in find_proxy_task()
  sched: Fix proxy/current (push,pull)ability
  sched: Add an initial sketch of the find_proxy_task() function
  sched: Fix runtime accounting w/ split exec & sched contexts
  sched: Move update_curr_task logic into update_curr_se
  locking/mutex: Add p->blocked_on wrappers for correctness checks
  locking/mutex: Rework task_struct::blocked_on
  sched: Add CONFIG_SCHED_PROXY_EXEC & boot argument to enable/disable
  sched/topology: Remove sched_domain_topology_level::flags
  x86/smpboot: avoid SMT domain attach/destroy if SMT is not enabled
  x86/smpboot: moves x86_topology to static initialize and truncate
  x86/smpboot: remove redundant CONFIG_SCHED_SMT
  smpboot: introduce SDTL_INIT() helper to tidy sched topology setup
  tools/sched: Add dl_bw_dump.py for printing bandwidth accounting info
  tools/sched: Add root_domains_dump.py which dumps root domains info
  sched/deadline: Fix accounting after global limits change
  sched/deadline: Reset extra_bw to max_bw when clearing root domains
  sched/deadline: Initialize dl_servers after SMP
  ...
2025-07-29 17:42:52 -07:00
Linus Torvalds
add07519ea Merge tag 'vfs-6.17-rc1.rust' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs rust updates from Christian Brauner:

 - Allow poll_table pointers to be NULL

 - Add Rust files to vfs MAINTAINERS entry

* tag 'vfs-6.17-rc1.rust' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  vfs: add Rust files to MAINTAINERS
  poll: rust: allow poll_table ptrs to be null
2025-07-28 14:44:43 -07:00
Shankari Anand
07dad44aa9 rust: kernel: move ARef and AlwaysRefCounted to sync::aref
Move the definitions of `ARef` and `AlwaysRefCounted` from `types.rs`
to a new file `sync/aref.rs`.  Define the corresponding `aref` module
under `rust/kernel/sync.rs`.  These types are better grouped in `sync`.

To avoid breaking existing imports, they are re-exported from `types.rs`.
Drop unused imports `mem::ManuallyDrop`, `ptr::NonNull` from `types.rs`,
they are now only used in `sync/aref.rs`, where they are already imported.

Suggested-by: Benno Lossin <lossin@kernel.org>
Link: https://github.com/Rust-for-Linux/linux/issues/1173
Signed-off-by: Shankari Anand <shankari.ak0208@gmail.com>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Link: https://lore.kernel.org/r/20250715110423.334744-1-shankari.ak0208@gmail.com
[ Added missing `///`. Changed module title. Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-07-22 13:52:14 +02:00
Andreas Hindborg
12717ebeff rust: types: add FOREIGN_ALIGN to ForeignOwnable
The current implementation of `ForeignOwnable` is leaking the type of the
opaque pointer to consumers of the API. This allows consumers of the opaque
pointer to rely on the information that can be extracted from the pointer
type.

To prevent this, change the API to the version suggested by Maira
Canal (link below): Remove `ForeignOwnable::PointedTo` in favor of a
constant, which specifies the alignment of the pointers returned by
`into_foreign`.

With this change, `ArcInner` no longer needs `pub` visibility, so change it
to private.

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Suggested-by: Maíra Canal <mcanal@igalia.com>
Link: https://lore.kernel.org/r/20240309235927.168915-3-mcanal@igalia.com
Acked-by: Danilo Krummrich <dakr@kernel.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Signed-off-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20250612-pointed-to-v3-1-b009006d86a1@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-07-14 23:55:24 +02:00
Peter Zijlstra
8f2146159b Merge branch 'tip/sched/urgent'
Avoid merge conflicts

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
2025-07-14 17:16:28 +02:00