Pull driver core and debugfs updates from Greg KH:
"Here is the big set of driver core and debugfs updates for 6.14-rc1.
Included in here is a bunch of driver core, PCI, OF, and platform rust
bindings (all acked by the different subsystem maintainers), hence the
merge conflict with the rust tree, and some driver core api updates to
mark things as const, which will also require some fixups due to new
stuff coming in through other trees in this merge window.
There are also a bunch of debugfs updates from Al, and there is at
least one user that does have a regression with these, but Al is
working on tracking down the fix for it. In my use (and everyone
else's linux-next use), it does not seem like a big issue at the
moment.
Here's a short list of the things in here:
- driver core rust bindings for PCI, platform, OF, and some i/o
functions.
We are almost at the "write a real driver in rust" stage now,
depending on what you want to do.
- misc device rust bindings and a sample driver to show how to use
them
- debugfs cleanups in the fs as well as the users of the fs api for
places where drivers got it wrong or were unnecessarily doing
things in complex ways.
- driver core const work, making more of the api take const * for
different parameters to make the rust bindings easier overall.
- other small fixes and updates
All of these have been in linux-next with all of the aforementioned
merge conflicts, and the one debugfs issue, which looks to be resolved
"soon""
* tag 'driver-core-6.14-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (95 commits)
rust: device: Use as_char_ptr() to avoid explicit cast
rust: device: Replace CString with CStr in property_present()
devcoredump: Constify 'struct bin_attribute'
devcoredump: Define 'struct bin_attribute' through macro
rust: device: Add property_present()
saner replacement for debugfs_rename()
orangefs-debugfs: don't mess with ->d_name
octeontx2: don't mess with ->d_parent or ->d_parent->d_name
arm_scmi: don't mess with ->d_parent->d_name
slub: don't mess with ->d_name
sof-client-ipc-flood-test: don't mess with ->d_name
qat: don't mess with ->d_name
xhci: don't mess with ->d_iname
mtu3: don't mess wiht ->d_iname
greybus/camera - stop messing with ->d_iname
mediatek: stop messing with ->d_iname
netdevsim: don't embed file_operations into your structs
b43legacy: make use of debugfs_get_aux()
b43: stop embedding struct file_operations into their objects
carl9170: stop embedding file_operations into their objects
...
Pull rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Finish the move to custom FFI integer types started in the previous
cycle and finally map 'long' to 'isize' and 'char' to 'u8'. Do a
few cleanups on top thanks to that.
- Start to use 'derive(CoercePointee)' on Rust >= 1.84.0.
This is a major milestone on the path to build the kernel using
only stable Rust features. In particular, previously we were using
the unstable features 'coerce_unsized', 'dispatch_from_dyn' and
'unsize', and now we will use the new 'derive_coerce_pointee' one,
which is on track to stabilization. This new feature is a macro
that essentially expands into code that internally uses the
unstable features that we were using before, without having to
expose those.
With it, stable Rust users, including the kernel, will be able to
build custom smart pointers that work with trait objects, e.g.:
fn f(p: &Arc<dyn Display>) {
pr_info!("{p}\n");
}
let a: Arc<dyn Display> = Arc::new(42i32, GFP_KERNEL)?;
let b: Arc<dyn Display> = Arc::new("hello there", GFP_KERNEL)?;
f(&a); // Prints "42".
f(&b); // Prints "hello there".
Together with the 'arbitrary_self_types' feature that we started
using in the previous cycle, using our custom smart pointers like
'Arc' will eventually only rely in stable Rust.
- Introduce 'PROCMACROLDFLAGS' environment variable to allow to link
Rust proc macros using different flags than those used for linking
Rust host programs (e.g. when 'rustc' uses a different C library
than the host programs' one), which Android needs.
- Help kernel builds under macOS with Rust enabled by accomodating
other naming conventions for dynamic libraries (i.e. '.so' vs.
'.dylib') which are used for Rust procedural macros. The actual
support for macOS (i.e. the rest of the pieces needed) is provided
out-of-tree by others, following the policy used for other parts of
the kernel by Kbuild.
- Run Clippy for 'rusttest' code too and clean the bits it spotted.
- Provide Clippy with the minimum supported Rust version to improve
the suggestions it gives.
- Document 'bindgen' 0.71.0 regression.
'kernel' crate:
- 'build_error!': move users of the hidden function to the documented
macro, prevent such uses in the future by moving the function
elsewhere and add the macro to the prelude.
- 'types' module: add improved version of 'ForeignOwnable::borrow_mut'
(which was removed in the past since it was problematic); change
'ForeignOwnable' pointer type to '*mut'.
- 'alloc' module: implement 'Display' for 'Box' and align the 'Debug'
implementation to it; add example (doctest) for 'ArrayLayout::new()'
- 'sync' module: document 'PhantomData' in 'Arc'; use
'NonNull::new_unchecked' in 'ForeignOwnable for Arc' impl.
- 'uaccess' module: accept 'Vec's with different allocators in
'UserSliceReader::read_all'.
- 'workqueue' module: enable run-testing a couple more doctests.
- 'error' module: simplify 'from_errno()'.
- 'block' module: fix formatting in code documentation (a lint to catch
these is being implemented).
- Avoid 'unwrap()'s in doctests, which also improves the examples by
showing how kernel code is supposed to be written.
- Avoid 'as' casts with 'cast{,_mut}' calls which are a bit safer.
And a few other cleanups"
* tag 'rust-6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/ojeda/linux: (32 commits)
kbuild: rust: add PROCMACROLDFLAGS
rust: uaccess: generalize userSliceReader to support any Vec
rust: kernel: add improved version of `ForeignOwnable::borrow_mut`
rust: kernel: reorder `ForeignOwnable` items
rust: kernel: change `ForeignOwnable` pointer to mut
rust: arc: split unsafe block, add missing comment
rust: types: avoid `as` casts
rust: arc: use `NonNull::new_unchecked`
rust: use derive(CoercePointee) on rustc >= 1.84.0
rust: alloc: add doctest for `ArrayLayout::new()`
rust: init: update `stack_try_pin_init` examples
rust: error: import `kernel`'s `LayoutError` instead of `core`'s
rust: str: replace unwraps with question mark operators
rust: page: remove unnecessary helper function from doctest
rust: rbtree: remove unwrap in asserts
rust: init: replace unwraps with question mark operators
rust: use host dylib naming convention to support macOS
rust: add `build_error!` to the prelude
rust: kernel: move `build_error` hidden function to prevent mistakes
rust: use the `build_error!` macro, not the hidden function
...
Previously, the `ForeignOwnable` trait had a method called `borrow_mut`
that was intended to provide mutable access to the inner value. However,
the method accidentally made it possible to change the address of the
object being modified, which usually isn't what we want. (And when we
want that, it can be done by calling `from_foreign` and `into_foreign`,
like how the old `borrow_mut` was implemented.)
In this patch, we introduce an alternate definition of `borrow_mut` that
solves the previous problem. Conceptually, given a pointer type `P` that
implements `ForeignOwnable`, the `borrow_mut` method gives you the same
kind of access as an `&mut P` would, except that it does not let you
change the pointer `P` itself.
This is analogous to how the existing `borrow` method provides the same
kind of access to the inner value as an `&P`.
Note that for types like `Arc`, having an `&mut Arc<T>` only gives you
immutable access to the inner `T`. This is because mutable references
assume exclusive access, but there might be other handles to the same
reference counted value, so the access isn't exclusive. The `Arc` type
implements this by making `borrow_mut` return the same type as `borrow`.
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
Reviewed-by: Andreas Hindborg <a.hindborg@kernel.org>
Signed-off-by: Tamir Duberstein <tamird@gmail.com>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/20241120-borrow-mut-v6-6-80dbadd00951@gmail.com
[ Updated to `crate::ffi::`. Reworded title slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The `kernel` crate relies on both `coerce_unsized` and `dispatch_from_dyn`
unstable features.
Alice Ryhl has proposed [1] the introduction of the unstable macro
`SmartPointer` to reduce such dependence, along with a RFC patch [2].
Since Rust 1.81.0 this macro, later renamed to `CoercePointee` in
Rust 1.84.0 [3], has been fully implemented with the naming discussion
resolved.
This feature is now on track to stabilization in the language.
In order to do so, we shall start using this macro in the `kernel` crate
to prove the functionality and utility of the macro as the justification
of its stabilization.
This patch makes this switch in such a way that the crate remains
backward compatible with older Rust compiler versions,
via the new Kconfig option `RUSTC_HAS_COERCE_POINTEE`.
A minimal demonstration example is added to the
`samples/rust/rust_print_main.rs` module.
Link: https://rust-lang.github.io/rfcs/3621-derive-smart-pointer.html [1]
Link: https://lore.kernel.org/all/20240823-derive-smart-pointer-v1-1-53769cd37239@google.com/ [2]
Link: https://github.com/rust-lang/rust/pull/131284 [3]
Signed-off-by: Xiangfei Ding <dingxiangfei2009@gmail.com>
Reviewed-by: Fiona Behrens <me@kloenk.dev>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20241203205050.679106-2-dingxiangfei2009@gmail.com
[ Fixed version to 1.84. Renamed option to `RUSTC_HAS_COERCE_POINTEE`
to match `CC_HAS_*` ones. Moved up new config option, closer to the
`CC_HAS_*` ones. Simplified Kconfig line. Fixed typos and slightly
reworded example and commit. Added Link to PR. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Since we've exposed Lock::from_raw() and Guard::new() publically, we
want to be able to make sure that we assert that a lock is actually held
when constructing a Guard for it to handle instances of unsafe
Guard::new() calls outside of our lock module.
Hence add a new method assert_is_held() to Backend, which uses lockdep
to check whether or not a lock has been acquired. When lockdep is
disabled, this has no overhead.
[Boqun: Resolve the conflicts with exposing Guard::new(), reword the
commit log a bit and format "unsafe { <statement>; }" into "unsafe {
<statement> }" for the consistency. ]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241125204139.656801-1-lyude@redhat.com
Since we added a `Lock::from_raw()` function previously, it makes sense
to also introduce an interface for creating a `Guard` from a reference
to a `Lock` for instances where we've derived the `Lock` from a raw
pointer and know that the lock is already acquired, there are such
usages in KMS API.
[Boqun: Add backquotes to type names, reformat the commit log, reword a
bit on the usage of KMS API]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Filipe Xavier <felipe_life@live.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241119231146.2298971-3-lyude@redhat.com
The KMS bindings [1] have a few bindings that require manually acquiring
specific locks before calling certain functions. At the moment though,
the only way of acquiring these locks in bindings is to simply call the
C locking functions directly - since said locks are not initialized on
the Rust side of things.
However - if we add `#[repr(C)]` to `Lock<(), B>`, then given `()` is a
ZST - `Lock<(), B>` becomes equivalent in data layout to its inner
`B::State` type. Since locks in C don't have data explicitly associated
with them anyway, we can take advantage of this to add a
`Lock::from_raw()` function that can translate a raw pointer to
`B::State` into its proper `Lock<(), B>` equivalent. This lets us simply
acquire a reference to the lock in question and work with it like it was
initialized on the Rust side of things, allowing us to use less unsafe
code to implement bindings with lock requirements.
[Boqun: Use "Link:" instead of a URL and format the commit log]
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://patchwork.freedesktop.org/series/131522/ [1]
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20241119231146.2298971-2-lyude@redhat.com
Pull rust updates from Miguel Ojeda:
"Toolchain and infrastructure:
- Enable a series of lints, including safety-related ones, e.g. the
compiler will now warn about missing safety comments, as well as
unnecessary ones. How safety documentation is organized is a
frequent source of review comments, thus having the compiler guide
new developers on where they are expected (and where not) is very
nice.
- Start using '#[expect]': an interesting feature in Rust (stabilized
in 1.81.0) that makes the compiler warn if an expected warning was
_not_ emitted. This is useful to avoid forgetting cleaning up
locally ignored diagnostics ('#[allow]'s).
- Introduce '.clippy.toml' configuration file for Clippy, the Rust
linter, which will allow us to tweak its behaviour. For instance,
our first use cases are declaring a disallowed macro and, more
importantly, enabling the checking of private items.
- Lints-related fixes and cleanups related to the items above.
- Migrate from 'receiver_trait' to 'arbitrary_self_types': to get the
kernel into stable Rust, one of the major pieces of the puzzle is
the support to write custom types that can be used as 'self', i.e.
as receivers, since the kernel needs to write types such as 'Arc'
that common userspace Rust would not. 'arbitrary_self_types' has
been accepted to become stable, and this is one of the steps
required to get there.
- Remove usage of the 'new_uninit' unstable feature.
- Use custom C FFI types. Includes a new 'ffi' crate to contain our
custom mapping, instead of using the standard library 'core::ffi'
one. The actual remapping will be introduced in a later cycle.
- Map '__kernel_{size_t,ssize_t,ptrdiff_t}' to 'usize'/'isize'
instead of 32/64-bit integers.
- Fix 'size_t' in bindgen generated prototypes of C builtins.
- Warn on bindgen < 0.69.5 and libclang >= 19.1 due to a double issue
in the projects, which we managed to trigger with the upcoming
tracepoint support. It includes a build test since some
distributions backported the fix (e.g. Debian -- thanks!). All
major distributions we list should be now OK except Ubuntu non-LTS.
'macros' crate:
- Adapt the build system to be able run the doctests there too; and
clean up and enable the corresponding doctests.
'kernel' crate:
- Add 'alloc' module with generic kernel allocator support and remove
the dependency on the Rust standard library 'alloc' and the
extension traits we used to provide fallible methods with flags.
Add the 'Allocator' trait and its implementations '{K,V,KV}malloc'.
Add the 'Box' type (a heap allocation for a single value of type
'T' that is also generic over an allocator and considers the
kernel's GFP flags) and its shorthand aliases '{K,V,KV}Box'. Add
'ArrayLayout' type. Add 'Vec' (a contiguous growable array type)
and its shorthand aliases '{K,V,KV}Vec', including iterator
support.
For instance, now we may write code such as:
let mut v = KVec::new();
v.push(1, GFP_KERNEL)?;
assert_eq!(&v, &[1]);
Treewide, move as well old users to these new types.
- 'sync' module: add global lock support, including the
'GlobalLockBackend' trait; the 'Global{Lock,Guard,LockedBy}' types
and the 'global_lock!' macro. Add the 'Lock::try_lock' method.
- 'error' module: optimize 'Error' type to use 'NonZeroI32' and make
conversion functions public.
- 'page' module: add 'page_align' function.
- Add 'transmute' module with the existing 'FromBytes' and 'AsBytes'
traits.
- 'block::mq::request' module: improve rendered documentation.
- 'types' module: extend 'Opaque' type documentation and add simple
examples for the 'Either' types.
drm/panic:
- Clean up a series of Clippy warnings.
Documentation:
- Add coding guidelines for lints and the '#[expect]' feature.
- Add Ubuntu to the list of distributions in the Quick Start guide.
MAINTAINERS:
- Add Danilo Krummrich as maintainer of the new 'alloc' module.
And a few other small cleanups and fixes"
* tag 'rust-6.13' of https://github.com/Rust-for-Linux/linux: (82 commits)
rust: alloc: Fix `ArrayLayout` allocations
docs: rust: remove spurious item in `expect` list
rust: allow `clippy::needless_lifetimes`
rust: warn on bindgen < 0.69.5 and libclang >= 19.1
rust: use custom FFI integer types
rust: map `__kernel_size_t` and friends also to usize/isize
rust: fix size_t in bindgen prototypes of C builtins
rust: sync: add global lock support
rust: macros: enable the rest of the tests
rust: macros: enable paste! use from macro_rules!
rust: enable macros::module! tests
rust: kbuild: expand rusttest target for macros
rust: types: extend `Opaque` documentation
rust: block: fix formatting of `kernel::block::mq::request` module
rust: macros: fix documentation of the paste! macro
rust: kernel: fix THIS_MODULE header path in ThisModule doc comment
rust: page: add Rust version of PAGE_ALIGN
rust: helpers: remove unnecessary header includes
rust: exports: improve grammar in commentary
drm/panic: allow verbose version check
...
Currently FFI integer types are defined in libcore. This commit creates
the `ffi` crate and asks bindgen to use that crate for FFI integer types
instead of `core::ffi`.
This commit is preparatory and no type changes are made in this commit
yet.
Signed-off-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240913213041.395655-4-gary@garyguo.net
[ Added `rustdoc`, `rusttest` and KUnit tests support. Rebased on top of
`rust-next` (e.g. migrated more `core::ffi` cases). Reworded crate
docs slightly and formatted. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The term "receiver" means that a type can be used as the type of `self`,
and thus enables method call syntax `foo.bar()` instead of
`Foo::bar(foo)`. Stable Rust as of today (1.81) enables a limited
selection of types (primitives and types in std, e.g. `Box` and `Arc`)
to be used as receivers, while custom types cannot.
We want the kernel `Arc` type to have the same functionality as the Rust
std `Arc`, so we use the `Receiver` trait (gated behind `receiver_trait`
unstable feature) to gain the functionality.
The `arbitrary_self_types` RFC [1] (tracking issue [2]) is accepted and
it will allow all types that implement a new `Receiver` trait (different
from today's unstable trait) to be used as receivers. This trait will be
automatically implemented for all `Deref` types, which include our `Arc`
type, so we no longer have to opt-in to be used as receiver. To prepare
us for the change, remove the `Receiver` implementation and the
associated feature. To still allow `Arc` and others to be used as method
receivers, turn on `arbitrary_self_types` feature instead.
This feature gate is introduced in 1.23.0. It used to enable both
`Deref` types and raw pointer types to be used as receivers, but the
latter is now split into a different feature gate in Rust 1.83 nightly.
We do not need receivers on raw pointers so this change would not affect
us and usage of `arbitrary_self_types` feature would work for all Rust
versions that we support (>=1.78).
Cc: Adrian Taylor <ade@hohum.me.uk>
Link: https://github.com/rust-lang/rfcs/pull/3519 [1]
Link: https://github.com/rust-lang/rust/issues/44874 [2]
Signed-off-by: Gary Guo <gary@garyguo.net>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/r/20240915132734.1653004-1-gary@garyguo.net
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
