Prepare for `core::ffi::CStr` taking the place of `kernel::str::CStr` by avoid methods that only exist on the latter. Link: https://github.com/Rust-for-Linux/linux/issues/1075 Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <lossin@kernel.org> Acked-by: Danilo Krummrich <dakr@kernel.org> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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
...
Starting with Rust 1.89.0 (expected 2025-08-07), the Rust compiler fails
to build the `rusttest` target due to undefined references such as:
kernel...-cgu.0:(.text....+0x116): undefined reference to
`rust_helper_kunit_get_current_test'
Moreover, tooling like `modpost` gets confused:
WARNING: modpost: missing MODULE_DESCRIPTION() in drivers/gpu/drm/nova/nova.o
ERROR: modpost: missing MODULE_LICENSE() in drivers/gpu/nova-core/nova_core.o
The reason behind both issues is that the Rust compiler will now [1]
treat `#[used]` as `#[used(linker)]` instead of `#[used(compiler)]`
for our targets. This means that the retain section flag (`R`,
`SHF_GNU_RETAIN`) will be used and that they will be marked as `unique`
too, with different IDs. In turn, that means we end up with undefined
references that did not get discarded in `rusttest` and that multiple
`.modinfo` sections are generated, which confuse tooling like `modpost`
because they only expect one.
Thus start using `#[used(compiler)]` to keep the previous behavior
and to be explicit about what we want. Sadly, it is an unstable feature
(`used_with_arg`) [2] -- we will talk to upstream Rust about it. The good
news is that it has been available for a long time (Rust >= 1.60) [3].
The changes should also be fine for previous Rust versions, since they
behave the same way as before [4].
Alternatively, we could use `#[no_mangle]` or `#[export_name = ...]`
since those still behave like `#[used(compiler)]`, but of course it is
not really what we want to express, and it requires other changes to
avoid symbol conflicts.
Cc: David Wood <david@davidtw.co>
Cc: Wesley Wiser <wwiser@gmail.com>
Cc: stable@vger.kernel.org # Needed in 6.12.y and later (Rust is pinned in older LTSs).
Link: https://github.com/rust-lang/rust/pull/140872 [1]
Link: https://github.com/rust-lang/rust/issues/93798 [2]
Link: https://github.com/rust-lang/rust/pull/91504 [3]
Link: https://godbolt.org/z/sxzWTMfzW [4]
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Acked-by: Björn Roy Baron <bjorn3_gh@protonmail.com>
Link: https://lore.kernel.org/r/20250712160103.1244945-3-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Use a consistent `# Examples` heading in rustdoc across the codebase. Some modules previously used `## Examples` (even when they should be available as top-level headers), while others used `# Example`, which deviates from the preferred `# Examples` style. Suggested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Benno Lossin <lossin@kernel.org> Link: https://lore.kernel.org/r/ddd5ce0ac20c99a72a4f1e4322d3de3911056922.1749545815.git.viresh.kumar@linaro.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Commit 38559da6afb2 ("rust: module: introduce `authors` key") introduced
a new `authors` key to support multiple module authors, while keeping
the old `author` key for backward compatibility.
Now that most in-tree modules have migrated to `authors`, remove:
1. The deprecated `author` key support from the module macro
2. Legacy `author` entries from remaining modules
Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com>
Acked-by: Andreas Hindborg <a.hindborg@kernel.org>
Reviewed-by: Benno Lossin <lossin@kernel.org>
Acked-by: Danilo Krummrich <dakr@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250609122200.179307-1-trintaeoitogc@gmail.com
[ Reworded slightly. - Miguel ]
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
In Rust 1.51.0, Clippy introduced the `ptr_as_ptr` lint [1]: > Though `as` casts between raw pointers are not terrible, > `pointer::cast` is safer because it cannot accidentally change the > pointer's mutability, nor cast the pointer to other types like `usize`. There are a few classes of changes required: - Modules generated by bindgen are marked `#[allow(clippy::ptr_as_ptr)]`. - Inferred casts (` as _`) are replaced with `.cast()`. - Ascribed casts (` as *... T`) are replaced with `.cast::<T>()`. - Multistep casts from references (` as *const _ as *const T`) are replaced with `core::ptr::from_ref(&x).cast()` with or without `::<T>` according to the previous rules. The `core::ptr::from_ref` call is required because `(x as *const _).cast::<T>()` results in inference failure. - Native literal C strings are replaced with `c_str!().as_char_ptr()`. - `*mut *mut T as _` is replaced with `let *mut *const T = (*mut *mut T)`.cast();` since pointer to pointer can be confusing. Apply these changes and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#ptr_as_ptr [1] Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Tamir Duberstein <tamird@gmail.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Tejun Heo <tj@kernel.org> Acked-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20250615-ptr-as-ptr-v12-1-f43b024581e8@gmail.com [ Added `.cast()` for `opp`. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
The `FwFunc` struct contains an function with a char pointer argument,
for which a `*const u8` pointer was used. This is not really the
"proper" type for this, so use a `*const kernel::ffi::c_char` pointer
instead.
This has no real functionality changes, since now `kernel::ffi::c_char`
(which bindgen uses for `char`) is now a type alias to `u8` anyways,
but before commit 1bae8729e50a ("rust: map `long` to `isize` and `char`
to `u8`") the concrete type of `kernel::ffi::c_char` depended on the
architecture (However all supported architectures at the time mapped to
`i8`).
This caused problems on the v6.13 tag when building for 32 bit arm (with
my patches), since back then `*const i8` was used in the function
argument and the function that bindgen generated used
`*const core::ffi::c_char` which Rust mapped to `*const u8` on 32 bit
arm. The stable v6.13.y branch does not have this issue since commit
1bae8729e50a ("rust: map `long` to `isize` and `char` to `u8`") was
backported.
This caused the following build error:
```
error[E0308]: mismatched types
--> rust/kernel/firmware.rs:20:4
|
20 | Self(bindings::request_firmware)
| ---- ^^^^^^^^^^^^^^^^^^^^^^^^^^ expected fn pointer, found fn item
| |
| arguments to this function are incorrect
|
= note: expected fn pointer `unsafe extern "C" fn(_, *const i8, _) -> _`
found fn item `unsafe extern "C" fn(_, *const u8, _) -> _ {request_firmware}`
note: tuple struct defined here
--> rust/kernel/firmware.rs:14:8
|
14 | struct FwFunc(
| ^^^^^^
error[E0308]: mismatched types
--> rust/kernel/firmware.rs:24:14
|
24 | Self(bindings::firmware_request_nowarn)
| ---- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected fn pointer, found fn item
| |
| arguments to this function are incorrect
|
= note: expected fn pointer `unsafe extern "C" fn(_, *const i8, _) -> _`
found fn item `unsafe extern "C" fn(_, *const u8, _) -> _ {firmware_request_nowarn}`
note: tuple struct defined here
--> rust/kernel/firmware.rs:14:8
|
14 | struct FwFunc(
| ^^^^^^
error[E0308]: mismatched types
--> rust/kernel/firmware.rs:64:45
|
64 | let ret = unsafe { func.0(pfw as _, name.as_char_ptr(), dev.as_raw()) };
| ------ ^^^^^^^^^^^^^^^^^^ expected `*const i8`, found `*const u8`
| |
| arguments to this function are incorrect
|
= note: expected raw pointer `*const i8`
found raw pointer `*const u8`
error: aborting due to 3 previous errors
```
Fixes: de6582833db0 ("rust: add firmware abstractions")
Cc: stable@vger.kernel.org
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Christian Schrefl <chrisi.schrefl@gmail.com>
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Link: https://lore.kernel.org/r/20250413-rust_arm_fix_fw_abstaction-v3-1-8dd7c0bbcd47@gmail.com
[ Add firmware prefix to commit subject. - Danilo ]
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Analogous to the `module!` macro `module_firmware!` adds additional firmware path strings to the .modinfo section. In contrast to `module!`, where path strings need to be string literals, path strings can be composed with the `firmware::ModInfoBuilder`. Some drivers require a lot of firmware files (such as nova-core) and hence benefit from more flexibility composing firmware path strings. Acked-by: Jarkko Sakkinen <jarkko@kernel.org> Link: https://lore.kernel.org/r/20250306222336.23482-4-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
The `firmware` field of the `module!` only accepts literal strings, which is due to the fact that it is implemented as a proc macro. Some drivers require a lot of firmware files (such as nova-core) and hence benefit from more flexibility composing firmware path strings. The `firmware::ModInfoBuilder` is a helper component to flexibly compose firmware path strings for the .modinfo section in const context. It is meant to be used in combination with `kernel::module_firmware!`. Co-developed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20250306222336.23482-3-dakr@kernel.org Signed-off-by: Danilo Krummrich <dakr@kernel.org>
The following FFI types are replaced compared to `core::ffi`: 1. `char` type is now always mapped to `u8`, since kernel uses `-funsigned-char` on the C code. `core::ffi` maps it to platform default ABI, which can be either signed or unsigned. 2. `long` is now always mapped to `isize`. It's very common in the kernel to use `long` to represent a pointer-sized integer, and in fact `intptr_t` is a typedef of `long` in the kernel. Enforce this mapping rather than mapping to `i32/i64` depending on platform can save us a lot of unnecessary casts. Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240913213041.395655-5-gary@garyguo.net [ Moved `uaccess` changes from the next commit, since they were irrefutable patterns that Rust >= 1.82.0 warns about. Reworded slightly and reformatted a few documentation comments. Rebased on top of `rust-next`. Added the removal of two casts to avoid Clippy warnings. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>