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2024-10-15rust: alloc: implement `ReallocFunc`Danilo Krummrich
`ReallocFunc` is an abstraction for the kernel's realloc derivates, such as `krealloc`, `vrealloc` and `kvrealloc`. All of the named functions share the same function signature and implement the same semantics. The `ReallocFunc` abstractions provides a generalized wrapper around those, to trivialize the implementation of `Kmalloc`, `Vmalloc` and `KVmalloc` in subsequent patches. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-5-dakr@kernel.org [ Added temporary `allow(dead_code)` for `dangling_from_layout` to clean warning in `rusttest` target as discussed in the list (but it is needed earlier, i.e. in this patch already). Added colon. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-15rust: miscdevice: fix warning on c_uint to u32 castAlice Ryhl
When building miscdevice with clippy warnings, the following warning is emitted: warning: casting to the same type is unnecessary (`u32` -> `u32`) --> /home/aliceryhl/rust-for-linux/rust/kernel/miscdevice.rs:220:28 | 220 | match T::ioctl(device, cmd as u32, arg as usize) { | ^^^^^^^^^^ help: try: `cmd` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast = note: `-W clippy::unnecessary-cast` implied by `-W clippy::all` = help: to override `-W clippy::all` add `#[allow(clippy::unnecessary_cast)]` Thus, fix it. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241015-miscdevice-cint-cast-v1-1-fcf4b75700ac@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-15rust: task: adjust safety comments in Task methodsAlice Ryhl
The `Task` struct has several safety comments that aren't so great. For example, the reason that it's okay to read the `pid` is that the field is immutable, so there is no data race, which is not what the safety comment says. Thus, improve the safety comments. Also add an `as_ptr` helper. This makes it easier to read the various accessors on Task, as `self.0` may be confusing syntax for new Rust users. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241015-task-safety-cmnts-v1-1-46ee92c82768@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-14rust: alloc: rename `KernelAllocator` to `Kmalloc`Danilo Krummrich
Subsequent patches implement `Vmalloc` and `KVmalloc` allocators, hence align `KernelAllocator` to this naming scheme. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-4-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14rust: alloc: separate `aligned_size` from `krealloc_aligned`Danilo Krummrich
Separate `aligned_size` from `krealloc_aligned`. Subsequent patches implement `Allocator` derivates, such as `Kmalloc`, that require `aligned_size` and replace the original `krealloc_aligned`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-3-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-14rust: alloc: add `Allocator` traitDanilo Krummrich
Add a kernel specific `Allocator` trait, that in contrast to the one in Rust's core library doesn't require unstable features and supports GFP flags. Subsequent patches add the following trait implementors: `Kmalloc`, `Vmalloc` and `KVmalloc`. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-2-dakr@kernel.org [ Fixed typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-13Merge tag 'driver-core-6.12-rc3' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core fixes from Greg KH: "Here is a single driver core fix, and a .mailmap update. The fix is for the rust driver core bindings, turned out that the from_raw binding wasn't a good idea (don't want to pass a pointer to a reference counted object without actually incrementing the pointer.) So this change fixes it up as the from_raw binding came in in -rc1. The other change is a .mailmap update. Both have been in linux-next for a while with no reported issues" * tag 'driver-core-6.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: mailmap: update mail for Fiona Behrens rust: device: change the from_raw() function
2024-10-10Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR (net-6.12-rc3). No conflicts and no adjacent changes. Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-10rust: kernel: move `FromBytes` and `AsBytes` traits to a new `transmute` moduleAliet Exposito Garcia
Refactor the `FromBytes` and `AsBytes` traits from `types.rs` into a new `transmute.rs` module: - Add `rust/kernel/transmute.rs` with the definitions of `FromBytes` and `AsBytes`. - Remove the same trait definitions from `rust/kernel/types.rs`. - Update `rust/kernel/uaccess.rs` to import `AsBytes` and `FromBytes` from `transmute.rs`. The traits and their implementations remain unchanged. Suggested-by: Benno Lossin <benno.lossin@proton.me> Link: https://github.com/Rust-for-Linux/linux/issues/1117 Signed-off-by: Aliet Exposito Garcia <aliet.exposito@gmail.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240918225115.2309224-2-aliet.exposito@gmail.com [ Rebased on top of the lints series and slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: error: optimize error type to use nonzeroFilipe Xavier
Optimize `Result<(), Error>` size by changing `Error` type to `NonZero*` for niche optimization. This reduces the space used by the `Result` type, as the `NonZero*` type enables the compiler to apply more efficient memory layout. For example, the `Result<(), Error>` changes size from 8 to 4 bytes. Link: https://github.com/Rust-for-Linux/linux/issues/1120 Signed-off-by: Filipe Xavier <felipe_life@live.com> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Link: https://lore.kernel.org/r/BL0PR02MB4914B9B088865CF237731207E9732@BL0PR02MB4914.namprd02.prod.outlook.com [ Removed unneeded block around `match`, added backticks in panic message and added intra-doc link. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: lock: add trylock method support for lock backendFilipe Xavier
Add a non-blocking trylock method to lock backend interface, mutex and spinlock implementations. It includes a C helper for spin_trylock. Rust Binder will use this method together with the new shrinker abstractions to avoid deadlocks in the memory shrinker. Link: https://lore.kernel.org/all/20240912-shrinker-v1-1-18b7f1253553@google.com Signed-off-by: Filipe Xavier <felipe_life@live.com> Reviewed-by: Fiona Behrens <me@kloenk.dev> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/BL0PR02MB4914579914884B5D7473B3D6E96A2@BL0PR02MB4914.namprd02.prod.outlook.com [ Slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-10rust: std_vendor: update dbg macro from Rust upstreamDeepak Thukral
`dbg!` contains adapted code from Rust upstream. Compare the kernel code with the Rust upstream one and update missing column numbers in `dbg!` outputs. Column numbers are not copied but adjusted for the kernel's examples. Suggested-by: Miguel Ojeda <ojeda@kernel.org> Link: https://github.com/Rust-for-Linux/linux/issues/1124 Signed-off-by: Deepak Thukral <iapain@gmail.com> Link: https://lore.kernel.org/r/20241004125616.49886-1-iapain@gmail.com [ Fixed typo and slightly reworded. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-09rust: miscdevice: add base miscdevice abstractionAlice Ryhl
Provide a `MiscDevice` trait that lets you specify the file operations that you wish to provide for your misc device. For now, only three file operations are provided: open, close, ioctl. These abstractions only support MISC_DYNAMIC_MINOR. This enforces that new miscdevices should not hard-code a minor number. When implementing ioctl, the Result type is used. This means that you can choose to return either of: * An integer of type isize. * An errno using the kernel::error::Error type. When returning an isize, the integer is returned verbatim. It's mainly intended for returning positive integers to userspace. However, it is technically possible to return errors via the isize return value too. To avoid having a dependency on files, this patch does not provide the file operations callbacks a pointer to the file. This means that they cannot check file properties such as O_NONBLOCK (which Binder needs). Support for that can be added as a follow-up. To avoid having a dependency on vma, this patch does not provide any way to implement mmap (which Binder needs). Support for that can be added as a follow-up. Rust Binder will use these abstractions to create the /dev/binder file when binderfs is disabled. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/rust-for-linux/20240328195457.225001-1-wedsonaf@gmail.com/ Link: https://lore.kernel.org/r/20241001-b4-miscdevice-v2-2-330d760041fa@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-09rust: types: add Opaque::try_ffi_initAlice Ryhl
This will be used by the miscdevice abstractions, as the C function `misc_register` is fallible. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Fiona Behrens <me@kloenk.dev> Link: https://lore.kernel.org/r/20241001-b4-miscdevice-v2-1-330d760041fa@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-08rust: add PidNamespaceChristian Brauner
The lifetime of `PidNamespace` is bound to `Task` and `struct pid`. The `PidNamespace` of a `Task` doesn't ever change once the `Task` is alive. A `unshare(CLONE_NEWPID)` or `setns(fd_pidns/pidfd, CLONE_NEWPID)` will not have an effect on the calling `Task`'s pid namespace. It will only effect the pid namespace of children created by the calling `Task`. This invariant guarantees that after having acquired a reference to a `Task`'s pid namespace it will remain unchanged. When a task has exited and been reaped `release_task()` will be called. This will set the `PidNamespace` of the task to `NULL`. So retrieving the `PidNamespace` of a task that is dead will return `NULL`. Note, that neither holding the RCU lock nor holding a referencing count to the `Task` will prevent `release_task()` being called. In order to retrieve the `PidNamespace` of a `Task` the `task_active_pid_ns()` function can be used. There are two cases to consider: (1) retrieving the `PidNamespace` of the `current` task (2) retrieving the `PidNamespace` of a non-`current` task From system call context retrieving the `PidNamespace` for case (1) is always safe and requires neither RCU locking nor a reference count to be held. Retrieving the `PidNamespace` after `release_task()` for current will return `NULL` but no codepath like that is exposed to Rust. Retrieving the `PidNamespace` from system call context for (2) requires RCU protection. Accessing `PidNamespace` outside of RCU protection requires a reference count that must've been acquired while holding the RCU lock. Note that accessing a non-`current` task means `NULL` can be returned as the non-`current` task could have already passed through `release_task()`. To retrieve (1) the `current_pid_ns!()` macro should be used which ensure that the returned `PidNamespace` cannot outlive the calling scope. The associated `current_pid_ns()` function should not be called directly as it could be abused to created an unbounded lifetime for `PidNamespace`. The `current_pid_ns!()` macro allows Rust to handle the common case of accessing `current`'s `PidNamespace` without RCU protection and without having to acquire a reference count. For (2) the `task_get_pid_ns()` method must be used. This will always acquire a reference on `PidNamespace` and will return an `Option` to force the caller to explicitly handle the case where `PidNamespace` is `None`, something that tends to be forgotten when doing the equivalent operation in `C`. Missing RCU primitives make it difficult to perform operations that are otherwise safe without holding a reference count as long as RCU protection is guaranteed. But it is not important currently. But we do want it in the future. Note for (2) the required RCU protection around calling `task_active_pid_ns()` synchronizes against putting the last reference of the associated `struct pid` of `task->thread_pid`. The `struct pid` stored in that field is used to retrieve the `PidNamespace` of the caller. When `release_task()` is called `task->thread_pid` will be `NULL`ed and `put_pid()` on said `struct pid` will be delayed in `free_pid()` via `call_rcu()` allowing everyone with an RCU protected access to the `struct pid` acquired from `task->thread_pid` to finish. Link: https://lore.kernel.org/r/20241002-brauner-rust-pid_namespace-v5-1-a90e70d44fde@kernel.org Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-08rust: add seqfile abstractionAlice Ryhl
This adds a simple seq file abstraction that lets you print to a seq file using ordinary Rust printing syntax. An example user from Rust Binder: pub(crate) fn full_debug_print( &self, m: &SeqFile, owner_inner: &mut ProcessInner, ) -> Result<()> { let prio = self.node_prio(); let inner = self.inner.access_mut(owner_inner); seq_print!( m, " node {}: u{:016x} c{:016x} pri {}:{} hs {} hw {} cs {} cw {}", self.debug_id, self.ptr, self.cookie, prio.sched_policy, prio.prio, inner.strong.has_count, inner.weak.has_count, inner.strong.count, inner.weak.count, ); if !inner.refs.is_empty() { seq_print!(m, " proc"); for node_ref in &inner.refs { seq_print!(m, " {}", node_ref.process.task.pid()); } } seq_print!(m, "\n"); for t in &inner.oneway_todo { t.debug_print_inner(m, " pending async transaction "); } Ok(()) } The `SeqFile` type is marked not thread safe so that `call_printf` can be a `&self` method. The alternative is to use `self: Pin<&mut Self>` which is inconvenient, or to have `SeqFile` wrap a pointer instead of wrapping the C struct directly. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241001-seqfile-v1-1-dfcd0fc21e96@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-08Merge patch series "File abstractions needed by Rust Binder"Christian Brauner
Alice Ryhl <aliceryhl@google.com> says: This patchset contains the file abstractions needed by the Rust implementation of the Binder driver. Please see the Rust Binder RFC for usage examples: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-0-08ba9197f637@google.com Users of "rust: types: add `NotThreadSafe`": [PATCH 5/9] rust: file: add `FileDescriptorReservation` Users of "rust: task: add `Task::current_raw`": [PATCH 7/9] rust: file: add `Kuid` wrapper [PATCH 8/9] rust: file: add `DeferredFdCloser` Users of "rust: file: add Rust abstraction for `struct file`": [PATCH RFC 02/20] rust_binder: add binderfs support to Rust binder [PATCH RFC 03/20] rust_binder: add threading support Users of "rust: cred: add Rust abstraction for `struct cred`": [PATCH RFC 05/20] rust_binder: add nodes and context managers [PATCH RFC 06/20] rust_binder: add oneway transactions [PATCH RFC 11/20] rust_binder: send nodes in transaction [PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support Users of "rust: security: add abstraction for secctx": [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: file: add `FileDescriptorReservation`": [PATCH RFC 13/20] rust_binder: add BINDER_TYPE_FD support [PATCH RFC 14/20] rust_binder: add BINDER_TYPE_FDA support Users of "rust: file: add `Kuid` wrapper": [PATCH RFC 05/20] rust_binder: add nodes and context managers [PATCH RFC 06/20] rust_binder: add oneway transactions Users of "rust: file: add abstraction for `poll_table`": [PATCH RFC 07/20] rust_binder: add epoll support This patchset has some uses of read_volatile in place of READ_ONCE. Please see the following rfc for context on this: https://lore.kernel.org/all/20231025195339.1431894-1-boqun.feng@gmail.com/ * patches from https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com: rust: file: add abstraction for `poll_table` rust: file: add `Kuid` wrapper rust: file: add `FileDescriptorReservation` rust: security: add abstraction for secctx rust: cred: add Rust abstraction for `struct cred` rust: file: add Rust abstraction for `struct file` rust: task: add `Task::current_raw` rust: types: add `NotThreadSafe` Link: https://lore.kernel.org/r/20240915-alice-file-v10-0-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-10-07rust: error: make conversion functions publicFilipe Xavier
Change visibility to public of functions in error.rs: from_err_ptr, from_errno, from_result and to_ptr. Additionally, remove dead_code annotations. Link: https://github.com/Rust-for-Linux/linux/issues/1105 Reviewed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Filipe Xavier <felipe_life@live.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/DM4PR14MB7276E6948E67B3B23D8EA847E9652@DM4PR14MB7276.namprd14.prod.outlook.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable arbitrary_self_types and remove `Receiver`Gary Guo
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>
2024-10-07rust: std_vendor: simplify `{ .. macro! .. }` with inner attributesMiguel Ojeda
It is cleaner to have a single inner attribute rather than needing several hidden lines to wrap the macro invocations. Thus simplify them. Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-20-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: start using the `#[expect(...)]` attributeMiguel Ojeda
In Rust, it is possible to `allow` particular warnings (diagnostics, lints) locally, making the compiler ignore instances of a given warning within a given function, module, block, etc. It is similar to `#pragma GCC diagnostic push` + `ignored` + `pop` in C: #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Wunused-function" static void f(void) {} #pragma GCC diagnostic pop But way less verbose: #[allow(dead_code)] fn f() {} By that virtue, it makes it possible to comfortably enable more diagnostics by default (i.e. outside `W=` levels) that may have some false positives but that are otherwise quite useful to keep enabled to catch potential mistakes. The `#[expect(...)]` attribute [1] takes this further, and makes the compiler warn if the diagnostic was _not_ produced. For instance, the following will ensure that, when `f()` is called somewhere, we will have to remove the attribute: #[expect(dead_code)] fn f() {} If we do not, we get a warning from the compiler: warning: this lint expectation is unfulfilled --> x.rs:3:10 | 3 | #[expect(dead_code)] | ^^^^^^^^^ | = note: `#[warn(unfulfilled_lint_expectations)]` on by default This means that `expect`s do not get forgotten when they are not needed. See the next commit for more details, nuances on its usage and documentation on the feature. The attribute requires the `lint_reasons` [2] unstable feature, but it is becoming stable in 1.81.0 (to be released on 2024-09-05) and it has already been useful to clean things up in this patch series, finding cases where the `allow`s should not have been there. Thus, enable `lint_reasons` and convert some of our `allow`s to `expect`s where possible. This feature was also an example of the ongoing collaboration between Rust and the kernel -- we tested it in the kernel early on and found an issue that was quickly resolved [3]. Cc: Fridtjof Stoldt <xfrednet@gmail.com> Cc: Urgau <urgau@numericable.fr> Link: https://rust-lang.github.io/rfcs/2383-lint-reasons.html#expect-lint-attribute [1] Link: https://github.com/rust-lang/rust/issues/54503 [2] Link: https://github.com/rust-lang/rust/issues/114557 [3] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-18-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable Clippy's `check-private-items`Miguel Ojeda
In Rust 1.76.0, Clippy added the `check-private-items` lint configuration option. When turned on (the default is off), it makes several lints check private items as well. In our case, it affects two lints we have enabled [1]: `missing_safety_doc` and `unnecessary_safety_doc`. It also seems to affect the new `too_long_first_doc_paragraph` lint [2], even though the documentation does not mention it. Thus allow the few instances remaining we currently hit and enable the lint. Link: https://doc.rust-lang.org/nightly/clippy/lint_configuration.html#check-private-items [1] Link: https://rust-lang.github.io/rust-clippy/master/index.html#/too_long_first_doc_paragraph [2] Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-16-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: provide proper code documentation titlesMiguel Ojeda
Rust 1.82.0's Clippy is introducing [1][2] a new warn-by-default lint, `too_long_first_doc_paragraph` [3], which is intended to catch titles of code documentation items that are too long (likely because no title was provided and the item documentation starts with a paragraph). This lint does not currently trigger anywhere, but it does detect a couple cases if checking for private items gets enabled (which we will do in the next commit): error: first doc comment paragraph is too long --> rust/kernel/init/__internal.rs:18:1 | 18 | / /// This is the module-internal type implementing `PinInit` and `Init`. It is unsafe to create this 19 | | /// type, since the closure needs to fulfill the same safety requirement as the 20 | | /// `__pinned_init`/`__init` functions. | |_ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#too_long_first_doc_paragraph = note: `-D clippy::too-long-first-doc-paragraph` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::too_long_first_doc_paragraph)]` error: first doc comment paragraph is too long --> rust/kernel/sync/arc/std_vendor.rs:3:1 | 3 | / //! The contents of this file come from the Rust standard library, hosted in 4 | | //! the <https://github.com/rust-lang/rust> repository, licensed under 5 | | //! "Apache-2.0 OR MIT" and adapted for kernel use. For copyright details, 6 | | //! see <https://github.com/rust-lang/rust/blob/master/COPYRIGHT>. | |_ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#too_long_first_doc_paragraph Thus clean those two instances. In addition, since we have a second `std_vendor.rs` file with a similar header, do the same there too (even if that one does not trigger the lint, because it is `doc(hidden)`). Link: https://github.com/rust-lang/rust/pull/129531 [1] Link: https://github.com/rust-lang/rust-clippy/pull/12993 [2] Link: https://rust-lang.github.io/rust-clippy/master/index.html#/too_long_first_doc_paragraph [3] Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-15-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: rbtree: fix `SAFETY` comments that should be `# Safety` sectionsMiguel Ojeda
The tag `SAFETY` is used for safety comments, i.e. `// SAFETY`, while a `Safety` section is used for safety preconditions in code documentation, i.e. `/// # Safety`. Fix the three instances recently added in `rbtree` that Clippy would have normally caught in a public item, so that we can enable checking of private items in one of the following commits. Fixes: 98c14e40e07a ("rust: rbtree: add cursor") Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-14-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: replace `clippy::dbg_macro` with `disallowed_macros`Miguel Ojeda
Back when we used Rust 1.60.0 (before Rust was merged in the kernel), we added `-Wclippy::dbg_macro` to the compilation flags. This worked great with our custom `dbg!` macro (vendored from `std`, but slightly modified to use the kernel printing facilities). However, in the very next version, 1.61.0, it stopped working [1] since the lint started to use a Rust diagnostic item rather than a path to find the `dbg!` macro [1]. This behavior remains until the current nightly (1.83.0). Therefore, currently, the `dbg_macro` is not doing anything, which explains why we can invoke `dbg!` in samples/rust/rust_print.rs`, as well as why changing the `#[allow()]`s to `#[expect()]`s in `std_vendor.rs` doctests does not work since they are not fulfilled. One possible workaround is using `rustc_attrs` like the standard library does. However, this is intended to be internal, and we just started supporting several Rust compiler versions, so it is best to avoid it. Therefore, instead, use `disallowed_macros`. It is a stable lint and is more flexible (in that we can provide different macros), although its diagnostic message(s) are not as nice as the specialized one (yet), and does not allow to set different lint levels per macro/path [2]. In turn, this requires allowing the (intentional) `dbg!` use in the sample, as one would have expected. Finally, in a single case, the `allow` is fixed to be an inner attribute, since otherwise it was not being applied. Link: https://github.com/rust-lang/rust-clippy/issues/11303 [1] Link: https://github.com/rust-lang/rust-clippy/issues/11307 [2] Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-13-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: sync: remove unneeded `#[allow(clippy::non_send_fields_in_send_ty)]`Miguel Ojeda
Rust 1.58.0 (before Rust was merged into the kernel) made Clippy's `non_send_fields_in_send_ty` lint part of the `suspicious` lint group for a brief window of time [1] until the minor version 1.58.1 got released a week after, where the lint was moved back to `nursery`. By that time, we had already upgraded to that Rust version, and thus we had `allow`ed the lint here for `CondVar`. Nowadays, Clippy's `non_send_fields_in_send_ty` would still trigger here if it were enabled. Moreover, if enabled, `Lock<T, B>` and `Task` would also require an `allow`. Therefore, it does not seem like someone is actually enabling it (in, e.g., a custom flags build). Finally, the lint does not appear to have had major improvements since then [2]. Thus remove the `allow` since it is unneeded. Link: https://github.com/rust-lang/rust/blob/master/RELEASES.md#version-1581-2022-01-20 [1] Link: https://github.com/rust-lang/rust-clippy/issues/8045 [2] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-11-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: init: remove unneeded `#[allow(clippy::disallowed_names)]`Miguel Ojeda
These few cases, unlike others in the same file, did not need the `allow`. Thus clean them up. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-10-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable `clippy::ignored_unit_patterns` lintMiguel Ojeda
In Rust 1.73.0, Clippy introduced the `ignored_unit_patterns` lint [1]: > Matching with `()` explicitly instead of `_` outlines the fact that > the pattern contains no data. Also it would detect a type change > that `_` would ignore. There is only a single case that requires a change: error: matching over `()` is more explicit --> rust/kernel/types.rs:176:45 | 176 | ScopeGuard::new_with_data((), move |_| cleanup()) | ^ help: use `()` instead of `_`: `()` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#ignored_unit_patterns = note: requested on the command line with `-D clippy::ignored-unit-patterns` Thus clean it up and enable the lint -- no functional change intended. Link: https://rust-lang.github.io/rust-clippy/master/index.html#/ignored_unit_patterns [1] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-8-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable `clippy::unnecessary_safety_comment` lintMiguel Ojeda
In Rust 1.67.0, Clippy added the `unnecessary_safety_comment` lint [1], which is the "inverse" of `undocumented_unsafe_blocks`: it finds places where safe code has a `// SAFETY` comment attached. The lint currently finds 3 places where we had such mistakes, thus it seems already quite useful. Thus clean those and enable it. Link: https://rust-lang.github.io/rust-clippy/master/index.html#/unnecessary_safety_comment [1] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-6-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: enable `clippy::undocumented_unsafe_blocks` lintMiguel Ojeda
Checking that we are not missing any `// SAFETY` comments in our `unsafe` blocks is something we have wanted to do for a long time, as well as cleaning up the remaining cases that were not documented [1]. Back when Rust for Linux started, this was something that could have been done via a script, like Rust's `tidy`. Soon after, in Rust 1.58.0, Clippy implemented the `undocumented_unsafe_blocks` lint [2]. Even though the lint has a few false positives, e.g. in some cases where attributes appear between the comment and the `unsafe` block [3], there are workarounds and the lint seems quite usable already. Thus enable the lint now. We still have a few cases to clean up, so just allow those for the moment by writing a `TODO` comment -- some of those may be good candidates for new contributors. Link: https://github.com/Rust-for-Linux/linux/issues/351 [1] Link: https://rust-lang.github.io/rust-clippy/master/#/undocumented_unsafe_blocks [2] Link: https://github.com/rust-lang/rust-clippy/issues/13189 [3] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-5-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: types: avoid repetition in `{As,From}Bytes` implsMiguel Ojeda
In order to provide `// SAFETY` comments for every `unsafe impl`, we would need to repeat them, which is not very useful and would be harder to read. We could perhaps allow the lint (ideally within a small module), but we can take the chance to avoid the repetition of the `impl`s themselves too by using a small local macro, like in other places where we have had to do this sort of thing. Thus add the straightforward `impl_{from,as}bytes!` macros and use them to implement `FromBytes`. This, in turn, will allow us in the next patch to place a `// SAFETY` comment that defers to the actual invocation of the macro. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-4-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: workqueue: remove unneeded ``#[allow(clippy::new_ret_no_self)]`Miguel Ojeda
Perform the same clean commit b2516f7af9d2 ("rust: kernel: remove `#[allow(clippy::new_ret_no_self)]`") did for a case that appeared in workqueue in parallel in commit 7324b88975c5 ("rust: workqueue: add helper for defining work_struct fields"): Clippy triggered a false positive on its `new_ret_no_self` lint when using the `pin_init!` macro. Since Rust 1.67.0, that does not happen anymore, since Clippy learnt to not warn about `-> impl Trait<Self>` [1][2]. The kernel nowadays uses Rust 1.72.1, thus remove the `#[allow]`. Link: https://github.com/rust-lang/rust-clippy/issues/7344 [1] Link: https://github.com/rust-lang/rust-clippy/pull/9733 [2] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Tested-by: Gary Guo <gary@garyguo.net> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240904204347.168520-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-07rust: types: add examples for the `Either` typeNell Shamrell-Harrington
We aim to have examples in all Rust types, thus add basic ones for the `Either` type. Suggested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Nell Shamrell-Harrington <nells@linux.microsoft.com> Tested-by: Dirk Behme <dirk.behme@de.bosch.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://rust-for-linux.zulipchat.com/#narrow/stream/291565/topic/x/near/467478085 Link: https://lore.kernel.org/r/20240918212052.8790-1-nells@linux.microsoft.com [ Reworded slightly. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-10-03rust: net::phy always define device_table in module_phy_driver macroFUJITA Tomonori
device_table in module_phy_driver macro is defined only when the driver is built as a module. So a PHY driver imports phy::DeviceId module in the following way then hits `unused import` warning when it's compiled as built-in: use kernel::net::phy::DeviceId; kernel::module_phy_driver! { drivers: [PhyQT2025], device_table: [ DeviceId::new_with_driver::<PhyQT2025>(), ], Put device_table in a const. It's not included in the kernel image if unused (when the driver is compiled as built-in), and the compiler doesn't complain. Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://patch.msgid.link/20240930134038.1309-1-fujita.tomonori@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-10-03rust: device: change the from_raw() functionGuilherme Giacomo Simoes
The function Device::from_raw() increments a refcount by a call to bindings::get_device(ptr). This can be confused because usually from_raw() functions don't increment a refcount. Hence, rename Device::from_raw() to avoid confuion with other "from_raw" semantics. The new name of function should be "get_device" to be consistent with the function get_device() already exist in .c files. This function body also changed, because the `into()` will convert the `&'a Device` into `ARef<Device>` and also call `inc_ref` from the `AlwaysRefCounted` trait implemented for Device. Signed-off-by: Guilherme Giacomo Simoes <trintaeoitogc@gmail.com> Acked-by: Danilo Krummrich <dakr@kernel.org> Closes: https://github.com/Rust-for-Linux/linux/issues/1088 Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20241001205603.106278-1-trintaeoitogc@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-01rust: kunit: use C-string literals to clean warningMiguel Ojeda
Starting with upstream Rust commit a5e3a3f9b6bd ("move `manual_c_str_literals` to complexity"), to be released in Rust 1.83.0 [1], Clippy now warns on `manual_c_str_literals` by default, e.g.: error: manually constructing a nul-terminated string --> rust/kernel/kunit.rs:21:13 | 21 | b"\x013%pA\0".as_ptr() as _, | ^^^^^^^^^^^^^ help: use a `c""` literal: `c"\x013%pA"` | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#manual_c_str_literals = note: `-D clippy::manual-c-str-literals` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::manual_c_str_literals)]` Apply the suggestion to clean up the warnings. Link: https://github.com/rust-lang/rust-clippy/pull/13263 [1] Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240927164414.560906-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-30rust: file: add abstraction for `poll_table`Alice Ryhl
The existing `CondVar` abstraction is a wrapper around `wait_queue_head`, but it does not support all use-cases of the C `wait_queue_head` type. To be specific, a `CondVar` cannot be registered with a `struct poll_table`. This limitation has the advantage that you do not need to call `synchronize_rcu` when destroying a `CondVar`. However, we need the ability to register a `poll_table` with a `wait_queue_head` in Rust Binder. To enable this, introduce a type called `PollCondVar`, which is like `CondVar` except that you can register a `poll_table`. We also introduce `PollTable`, which is a safe wrapper around `poll_table` that is intended to be used with `PollCondVar`. The destructor of `PollCondVar` unconditionally calls `synchronize_rcu` to ensure that the removal of epoll waiters has fully completed before the `wait_queue_head` is destroyed. That said, `synchronize_rcu` is rather expensive and is not needed in all cases: If we have never registered a `poll_table` with the `wait_queue_head`, then we don't need to call `synchronize_rcu`. (And this is a common case in Binder - not all processes use Binder with epoll.) The current implementation does not account for this, but if we find that it is necessary to improve this, a future patch could store a boolean next to the `wait_queue_head` to keep track of whether a `poll_table` has ever been registered. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-8-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: file: add `Kuid` wrapperAlice Ryhl
Adds a wrapper around `kuid_t` called `Kuid`. This allows us to define various operations on kuids such as equality and current_euid. It also lets us provide conversions from kuid into userspace values. Rust Binder needs these operations because it needs to compare kuids for equality, and it needs to tell userspace about the pid and uid of incoming transactions. To read kuids from a `struct task_struct`, you must currently use various #defines that perform the appropriate field access under an RCU read lock. Currently, we do not have a Rust wrapper for rcu_read_lock, which means that for this patch, there are two ways forward: 1. Inline the methods into Rust code, and use __rcu_read_lock directly rather than the rcu_read_lock wrapper. This gives up lockdep for these usages of RCU. 2. Wrap the various #defines in helpers and call the helpers from Rust. This patch uses the second option. One possible disadvantage of the second option is the possible introduction of speculation gadgets, but as discussed in [1], the risk appears to be acceptable. Of course, once a wrapper for rcu_read_lock is available, it is preferable to use that over either of the two above approaches. Link: https://lore.kernel.org/all/202312080947.674CD2DC7@keescook/ [1] Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-7-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: file: add `FileDescriptorReservation`Wedson Almeida Filho
Allow for the creation of a file descriptor in two steps: first, we reserve a slot for it, then we commit or drop the reservation. The first step may fail (e.g., the current process ran out of available slots), but commit and drop never fail (and are mutually exclusive). This is needed by Rust Binder when fds are sent from one process to another. It has to be a two-step process to properly handle the case where multiple fds are sent: The operation must fail or succeed atomically, which we achieve by first reserving the fds we need, and only installing the files once we have reserved enough fds to send the files. Fd reservations assume that the value of `current` does not change between the call to get_unused_fd_flags and the call to fd_install (or put_unused_fd). By not implementing the Send trait, this abstraction ensures that the `FileDescriptorReservation` cannot be moved into a different process. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-6-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: security: add abstraction for secctxAlice Ryhl
Add an abstraction for viewing the string representation of a security context. This is needed by Rust Binder because it has a feature where a process can view the string representation of the security context for incoming transactions. The process can use that to authenticate incoming transactions, and since the feature is provided by the kernel, the process can trust that the security context is legitimate. This abstraction makes the following assumptions about the C side: * When a call to `security_secid_to_secctx` is successful, it returns a pointer and length. The pointer references a byte string and is valid for reading for that many bytes. * The string may be referenced until `security_release_secctx` is called. * If CONFIG_SECURITY is set, then the three methods mentioned in rust/helpers are available without a helper. (That is, they are not a #define or `static inline`.) Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-5-88484f7a3dcf@google.com Acked-by: Paul Moore <paul@paul-moore.com> Reviewed-by: Kees Cook <kees@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: cred: add Rust abstraction for `struct cred`Wedson Almeida Filho
Add a wrapper around `struct cred` called `Credential`, and provide functionality to get the `Credential` associated with a `File`. Rust Binder must check the credentials of processes when they attempt to perform various operations, and these checks usually take a `&Credential` as parameter. The security_binder_set_context_mgr function would be one example. This patch is necessary to access these security_* methods from Rust. This Rust abstraction makes the following assumptions about the C side: * `struct cred` is refcounted with `get_cred`/`put_cred`. * It's okay to transfer a `struct cred` across threads, that is, you do not need to call `put_cred` on the same thread as where you called `get_cred`. * The `euid` field of a `struct cred` never changes after initialization. * The `f_cred` field of a `struct file` never changes after initialization. Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-4-88484f7a3dcf@google.com Reviewed-by: Kees Cook <kees@kernel.org> Reviewed-by: Paul Moore <paul@paul-moore.com> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: file: add Rust abstraction for `struct file`Wedson Almeida Filho
This abstraction makes it possible to manipulate the open files for a process. The new `File` struct wraps the C `struct file`. When accessing it using the smart pointer `ARef<File>`, the pointer will own a reference count to the file. When accessing it as `&File`, then the reference does not own a refcount, but the borrow checker will ensure that the reference count does not hit zero while the `&File` is live. Since this is intended to manipulate the open files of a process, we introduce an `fget` constructor that corresponds to the C `fget` method. In future patches, it will become possible to create a new fd in a process and bind it to a `File`. Rust Binder will use these to send fds from one process to another. We also provide a method for accessing the file's flags. Rust Binder will use this to access the flags of the Binder fd to check whether the non-blocking flag is set, which affects what the Binder ioctl does. This introduces a struct for the EBADF error type, rather than just using the Error type directly. This has two advantages: * `File::fget` returns a `Result<ARef<File>, BadFdError>`, which the compiler will represent as a single pointer, with null being an error. This is possible because the compiler understands that `BadFdError` has only one possible value, and it also understands that the `ARef<File>` smart pointer is guaranteed non-null. * Additionally, we promise to users of the method that the method can only fail with EBADF, which means that they can rely on this promise without having to inspect its implementation. That said, there are also two disadvantages: * Defining additional error types involves boilerplate. * The question mark operator will only utilize the `From` trait once, which prevents you from using the question mark operator on `BadFdError` in methods that return some third error type that the kernel `Error` is convertible into. (However, it works fine in methods that return `Error`.) Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-3-88484f7a3dcf@google.com Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: task: add `Task::current_raw`Alice Ryhl
Introduces a safe function for getting a raw pointer to the current task. When writing bindings that need to access the current task, it is often more convenient to call a method that directly returns a raw pointer than to use the existing `Task::current` method. However, the only way to do that is `bindings::get_current()` which is unsafe since it calls into C. By introducing `Task::current_raw()`, it becomes possible to obtain a pointer to the current task without using unsafe. Link: https://lore.kernel.org/all/CAH5fLgjT48X-zYtidv31mox3C4_Ogoo_2cBOCmX0Ang3tAgGHA@mail.gmail.com/ Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-2-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-30rust: types: add `NotThreadSafe`Alice Ryhl
This introduces a new marker type for types that shouldn't be thread safe. By adding a field of this type to a struct, it becomes non-Send and non-Sync, which means that it cannot be accessed in any way from threads other than the one it was created on. This is useful for APIs that require globals such as `current` to remain constant while the value exists. We update two existing users in the Kernel to use this helper: * `Task::current()` - moving the return type of this value to a different thread would not be safe as you can no longer be guaranteed that the `current` pointer remains valid. * Lock guards. Mutexes and spinlocks should be unlocked on the same thread as where they were locked, so we enforce this using the Send trait. There are also additional users in later patches of this patchset. See [1] and [2] for the discussion that led to the introduction of this patch. Link: https://lore.kernel.org/all/nFDPJFnzE9Q5cqY7FwSMByRH2OAn_BpI4H53NQfWIlN6I2qfmAqnkp2wRqn0XjMO65OyZY4h6P4K2nAGKJpAOSzksYXaiAK_FoH_8QbgBI4=@proton.me/ [1] Link: https://lore.kernel.org/all/nFDPJFnzE9Q5cqY7FwSMByRH2OAn_BpI4H53NQfWIlN6I2qfmAqnkp2wRqn0XjMO65OyZY4h6P4K2nAGKJpAOSzksYXaiAK_FoH_8QbgBI4=@proton.me/ [2] Suggested-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Reviewed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240915-alice-file-v10-1-88484f7a3dcf@google.com Signed-off-by: Christian Brauner <brauner@kernel.org>
2024-09-26rust: sync: require `T: Sync` for `LockedBy::access`Alice Ryhl
The `LockedBy::access` method only requires a shared reference to the owner, so if we have shared access to the `LockedBy` from several threads at once, then two threads could call `access` in parallel and both obtain a shared reference to the inner value. Thus, require that `T: Sync` when calling the `access` method. An alternative is to require `T: Sync` in the `impl Sync for LockedBy`. This patch does not choose that approach as it gives up the ability to use `LockedBy` with `!Sync` types, which is okay as long as you only use `access_mut`. Cc: stable@vger.kernel.org Fixes: 7b1f55e3a984 ("rust: sync: introduce `LockedBy`") Signed-off-by: Alice Ryhl <aliceryhl@google.com> Suggested-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240915-locked-by-sync-fix-v2-1-1a8d89710392@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-26rust: kernel: sort Rust modulesMiguel Ojeda
Rust modules are intended to be sorted, thus do so. This makes `rustfmtcheck` to pass again. Fixes: 570172569238 ("Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux") Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240926124751.345471-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-25Merge tag 'rust-6.12' of https://github.com/Rust-for-Linux/linuxLinus Torvalds
Pull Rust updates from Miguel Ojeda: "Toolchain and infrastructure: - Support 'MITIGATION_{RETHUNK,RETPOLINE,SLS}' (which cleans up objtool warnings), teach objtool about 'noreturn' Rust symbols and mimic '___ADDRESSABLE()' for 'module_{init,exit}'. With that, we should be objtool-warning-free, so enable it to run for all Rust object files. - KASAN (no 'SW_TAGS'), KCFI and shadow call sanitizer support. - Support 'RUSTC_VERSION', including re-config and re-build on change. - Split helpers file into several files in a folder, to avoid conflicts in it. Eventually those files will be moved to the right places with the new build system. In addition, remove the need to manually export the symbols defined there, reusing existing machinery for that. - Relax restriction on configurations with Rust + GCC plugins to just the RANDSTRUCT plugin. 'kernel' crate: - New 'list' module: doubly-linked linked list for use with reference counted values, which is heavily used by the upcoming Rust Binder. This includes 'ListArc' (a wrapper around 'Arc' that is guaranteed unique for the given ID), 'AtomicTracker' (tracks whether a 'ListArc' exists using an atomic), 'ListLinks' (the prev/next pointers for an item in a linked list), 'List' (the linked list itself), 'Iter' (an iterator over a 'List'), 'Cursor' (a cursor into a 'List' that allows to remove elements), 'ListArcField' (a field exclusively owned by a 'ListArc'), as well as support for heterogeneous lists. - New 'rbtree' module: red-black tree abstractions used by the upcoming Rust Binder. This includes 'RBTree' (the red-black tree itself), 'RBTreeNode' (a node), 'RBTreeNodeReservation' (a memory reservation for a node), 'Iter' and 'IterMut' (immutable and mutable iterators), 'Cursor' (bidirectional cursor that allows to remove elements), as well as an entry API similar to the Rust standard library one. - 'init' module: add 'write_[pin_]init' methods and the 'InPlaceWrite' trait. Add the 'assert_pinned!' macro. - 'sync' module: implement the 'InPlaceInit' trait for 'Arc' by introducing an associated type in the trait. - 'alloc' module: add 'drop_contents' method to 'BoxExt'. - 'types' module: implement the 'ForeignOwnable' trait for 'Pin<Box<T>>' and improve the trait's documentation. In addition, add the 'into_raw' method to the 'ARef' type. - 'error' module: in preparation for the upcoming Rust support for 32-bit architectures, like arm, locally allow Clippy lint for those. Documentation: - https://rust.docs.kernel.org has been announced, so link to it. - Enable rustdoc's "jump to definition" feature, making its output a bit closer to the experience in a cross-referencer. - Debian Testing now also provides recent Rust releases (outside of the freeze period), so add it to the list. MAINTAINERS: - Trevor is joining as reviewer of the "RUST" entry. And a few other small bits" * tag 'rust-6.12' of https://github.com/Rust-for-Linux/linux: (54 commits) kasan: rust: Add KASAN smoke test via UAF kbuild: rust: Enable KASAN support rust: kasan: Rust does not support KHWASAN kbuild: rust: Define probing macros for rustc kasan: simplify and clarify Makefile rust: cfi: add support for CFI_CLANG with Rust cfi: add CONFIG_CFI_ICALL_NORMALIZE_INTEGERS rust: support for shadow call stack sanitizer docs: rust: include other expressions in conditional compilation section kbuild: rust: replace proc macros dependency on `core.o` with the version text kbuild: rust: rebuild if the version text changes kbuild: rust: re-run Kconfig if the version text changes kbuild: rust: add `CONFIG_RUSTC_VERSION` rust: avoid `box_uninit_write` feature MAINTAINERS: add Trevor Gross as Rust reviewer rust: rbtree: add `RBTree::entry` rust: rbtree: add cursor rust: rbtree: add mutable iterator rust: rbtree: add iterator rust: rbtree: add red-black tree implementation backed by the C version ...
2024-09-05Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski
Cross-merge networking fixes after downstream PR. Conflicts: drivers/net/phy/phy_device.c 2560db6ede1a ("net: phy: Fix missing of_node_put() for leds") 1dce520abd46 ("net: phy: Use for_each_available_child_of_node_scoped()") https://lore.kernel.org/20240904115823.74333648@canb.auug.org.au Adjacent changes: drivers/net/ethernet/xilinx/xilinx_axienet.h drivers/net/ethernet/xilinx/xilinx_axienet_main.c 858430db28a5 ("net: xilinx: axienet: Fix race in axienet_stop") 76abb5d675c4 ("net: xilinx: axienet: Add statistics support") Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2024-09-04rust: avoid `box_uninit_write` featureMiguel Ojeda
Like commit 0903b9e2a46c ("rust: alloc: eschew `Box<MaybeUninit<T>>::write`"), but for the new `rbtree` and `alloc` code. That is, `feature(new_uninit)` [1] got partially stabilized [2] for Rust 1.82.0 (expected to be released on 2024-10-17), but it did not include `Box<MaybeUninit<T>>::write`, which got split into `feature(box_uninit_write)` [3]. To avoid relying on a new unstable feature, rewrite the `write` + `assume_init` pair manually. Link: https://github.com/rust-lang/rust/issues/63291 [1] Link: https://github.com/rust-lang/rust/pull/129401 [2] Link: https://github.com/rust-lang/rust/issues/129397 [3] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Matt Gilbride <mattgilbride@google.com> Link: https://lore.kernel.org/r/20240904144229.18592-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-31rust: rbtree: add `RBTree::entry`Alice Ryhl
This mirrors the entry API [1] from the Rust standard library on `RBTree`. This API can be used to access the entry at a specific key and make modifications depending on whether the key is vacant or occupied. This API is useful because it can often be used to avoid traversing the tree multiple times. This is used by binder to look up and conditionally access or insert a value, depending on whether it is there or not [2]. Link: https://doc.rust-lang.org/stable/std/collections/btree_map/enum.Entry.html [1] Link: https://android-review.googlesource.com/c/kernel/common/+/2849906 [2] Signed-off-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Matt Gilbride <mattgilbride@google.com> Link: https://lore.kernel.org/r/20240822-b4-rbtree-v12-5-014561758a57@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>