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* rust: use derive(CoercePointee) on rustc >= 1.84.0Xiangfei Ding2025-01-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
* rust: alloc: update module comment of alloc.rsDanilo Krummrich2024-10-151-1/+1
| | | | | | | | | | | | | | | Before we remove Rust's alloc crate, rewrite the module comment in alloc.rs to avoid a rustdoc warning. Besides that, the module comment in alloc.rs isn't correct anymore, we're no longer extending Rust's alloc crate. 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/20241004154149.93856-28-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: implement `Cmalloc` in module allocator_testDanilo Krummrich2024-10-151-1/+0
| | | | | | | | | | | | | | | | | | | So far the kernel's `Box` and `Vec` types can't be used by userspace test cases, since all users of those types (e.g. `CString`) use kernel allocators for instantiation. In order to allow userspace test cases to make use of such types as well, implement the `Cmalloc` allocator within the allocator_test module and type alias all kernel allocators to `Cmalloc`. The `Cmalloc` allocator uses libc's `realloc()` function as allocator backend. 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/20241004154149.93856-26-dakr@kernel.org [ Removed the temporary `allow(dead_code)` as discussed in the list and fixed typo, added backticks. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: implement `contains` for `Flags`Danilo Krummrich2024-10-151-1/+6
| | | | | | | | | | | | | | | Provide a simple helper function to check whether given flags do contain one or multiple other flags. This is used by a subsequent patch implementing the Cmalloc `Allocator` to check for __GFP_ZERO. 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/20241004154149.93856-25-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: remove `VecExt` extensionDanilo Krummrich2024-10-151-1/+0
| | | | | | | | | | | | Now that all existing `Vec` users were moved to the kernel `Vec` type, remove the `VecExt` extension. 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/20241004154149.93856-21-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: implement `IntoIterator` for `Vec`Danilo Krummrich2024-10-151-0/+1
| | | | | | | | | | | | | | | | | | | | | | Implement `IntoIterator` for `Vec`, `Vec`'s `IntoIter` type, as well as `Iterator` for `IntoIter`. `Vec::into_iter` disassembles the `Vec` into its raw parts; additionally, `IntoIter` keeps track of a separate pointer, which is incremented correspondingly as the iterator advances, while the length, or the count of elements, is decremented. This also means that `IntoIter` takes the ownership of the backing buffer and is responsible to drop the remaining elements and free the backing buffer, if it's dropped. 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/20241004154149.93856-18-dakr@kernel.org [ Fixed typos. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: implement kernel `Vec` typeDanilo Krummrich2024-10-151-0/+6
| | | | | | | | | | | | | | | | | | | | | | | `Vec` provides a contiguous growable array type with contents allocated with the kernel's allocators (e.g. `Kmalloc`, `Vmalloc` or `KVmalloc`). In contrast to Rust's stdlib `Vec` type, the kernel `Vec` type considers the kernel's GFP flags for all appropriate functions, always reports allocation failures through `Result<_, AllocError>` and remains independent from unstable features. [ This patch starts using a new unstable feature, `inline_const`, but it was stabilized in Rust 1.79.0, i.e. the next version after the minimum one, thus it will not be an issue. - Miguel ] 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/20241004154149.93856-17-dakr@kernel.org [ Cleaned `rustdoc` unescaped backtick warning, added a couple more backticks elsewhere, fixed typos, sorted `feature`s, rewrapped documentation lines. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: introduce `ArrayLayout`Benno Lossin2024-10-151-0/+1
| | | | | | | | | | | | | | | | | | | When allocating memory for arrays using allocators, the `Layout::array` function is typically used. It returns a result, since the given size might be too big. However, `Vec` and its iterators store their allocated capacity and thus they already did check that the size is not too big. The `ArrayLayout` type provides this exact behavior, as it can be infallibly converted into a `Layout`. Instead of a `usize` capacity, `Vec` and other similar array-storing types can use `ArrayLayout` instead. Reviewed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Danilo Krummrich <dakr@kernel.org> Link: https://lore.kernel.org/r/20241004154149.93856-16-dakr@kernel.org [ Formatted a few comments. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: remove extension of std's `Box`Danilo Krummrich2024-10-151-1/+0
| | | | | | | | | | | | Now that all existing `Box` users were moved to the kernel `Box` type, remove the `BoxExt` extension and all other related extensions. 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/20241004154149.93856-14-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: implement kernel `Box`Danilo Krummrich2024-10-151-0/+6
| | | | | | | | | | | | | | | | | | `Box` provides the simplest way to allocate memory for a generic type with one of the kernel's allocators, e.g. `Kmalloc`, `Vmalloc` or `KVmalloc`. In contrast to Rust's `Box` type, the kernel `Box` type considers the kernel's GFP flags for all appropriate functions, always reports allocation failures through `Result<_, AllocError>` and remains independent from unstable features. 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/20241004154149.93856-12-dakr@kernel.org [ Added backticks, fixed typos. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: add __GFP_NOWARN to `Flags`Danilo Krummrich2024-10-151-0/+5
| | | | | | | | | | | | Some test cases in subsequent patches provoke allocation failures. Add `__GFP_NOWARN` to enable test cases to silence unpleasant warnings. 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/20241004154149.93856-11-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: add module `allocator_test`Danilo Krummrich2024-10-151-2/+7
| | | | | | | | | | | | | | | | | | `Allocator`s, such as `Kmalloc`, will be used by e.g. `Box` and `Vec` in subsequent patches, and hence this dependency propagates throughout the whole kernel. Add the `allocator_test` module that provides an empty implementation for all `Allocator`s in the kernel, such that we don't break the `rusttest` make target in subsequent patches. 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/20241004154149.93856-8-dakr@kernel.org [ Added missing `_old_layout` parameter as discussed. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: make `allocator` module publicDanilo Krummrich2024-10-151-1/+1
| | | | | | | | | | | | Subsequent patches implement allocators such as `Kmalloc`, `Vmalloc`, `KVmalloc`; we need them to be available outside of the kernel crate as well. 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/20241004154149.93856-6-dakr@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: implement `ReallocFunc`Danilo Krummrich2024-10-151-0/+9
| | | | | | | | | | | | | | | | | | | `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>
* rust: alloc: add `Allocator` traitDanilo Krummrich2024-10-141-0/+101
| | | | | | | | | | | | | | | | | 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>
* rust: add abstraction for `struct page`Alice Ryhl2024-07-081-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adds a new struct called `Page` that wraps a pointer to `struct page`. This struct is assumed to hold ownership over the page, so that Rust code can allocate and manage pages directly. The page type has various methods for reading and writing into the page. These methods will temporarily map the page to allow the operation. All of these methods use a helper that takes an offset and length, performs bounds checks, and returns a pointer to the given offset in the page. This patch only adds support for pages of order zero, as that is all Rust Binder needs. However, it is written to make it easy to add support for higher-order pages in the future. To do that, you would add a const generic parameter to `Page` that specifies the order. Most of the methods do not need to be adjusted, as the logic for dealing with mapping multiple pages at once can be isolated to just the `with_pointer_into_page` method. Rust Binder needs to manage pages directly as that is how transactions are delivered: Each process has an mmap'd region for incoming transactions. When an incoming transaction arrives, the Binder driver will choose a region in the mmap, allocate and map the relevant pages manually, and copy the incoming transaction directly into the page. This architecture allows the driver to copy transactions directly from the address space of one process to another, without an intermediate copy to a kernel buffer. This code is based on Wedson's page abstractions from the old rust branch, but it has been modified by Alice by removing the incomplete support for higher-order pages, by introducing the `with_*` helpers to consolidate the bounds checking logic into a single place, and various other changes. Co-developed-by: Wedson Almeida Filho <wedsonaf@gmail.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Andreas Hindborg <a.hindborg@samsung.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240528-alice-mm-v7-4-78222c31b8f4@google.com [ Fixed typos and added a few intra-doc links. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: add __GFP_HIGHMEM flagAlice Ryhl2024-07-081-0/+8
| | | | | | | | | | | | | | | | | | | | Make it possible to allocate memory that doesn't need to mapped into the kernel's address space. This flag is useful together with Page::alloc_page [1]. Rust Binder needs this for the memory that holds incoming transactions for each process. Each process will have a few megabytes of memory allocated with this flag, which is mapped into the process using vm_insert_page. When the kernel copies data for an incoming transaction into a process's memory region, it will use kmap_local_page to temporarily map pages that are being modified. There is no need for them to take up address space in the kernel when the kernel is not writing an incoming transaction into the page. Link: https://lore.kernel.org/all/20240528-alice-mm-v7-4-78222c31b8f4@google.com/ [1] Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240607-highmem-v1-1-d18c5ca4072f@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: fix typo in docs for GFP_NOWAITAlice Ryhl2024-07-081-1/+1
| | | | | | | | | Fix a typo in alloc.rs by replacing Ror with For. Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com> Link: https://lore.kernel.org/r/20240529083452.779865-1-aliceryhl@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: kernel: remove redundant importsMiguel Ojeda2024-05-051-1/+0
| | | | | | | | | | | | | | | | | | | | | | | Rust's `unused_imports` lint covers both unused and redundant imports. In the upcoming 1.78.0, the lint detects more cases of redundant imports [1], e.g.: error: the item `bindings` is imported redundantly --> rust/kernel/print.rs:38:9 | 38 | use crate::bindings; | ^^^^^^^^^^^^^^^ the item `bindings` is already defined by prelude Most cases are `use crate::bindings`, plus a few other items like `Box`. Thus clean them up. Note that, in the `bindings` case, the message "defined by prelude" above means the extern prelude, i.e. the `--extern` flags we pass. Link: https://github.com/rust-lang/rust/pull/117772 [1] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240401212303.537355-3-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: kernel: remove usage of `allocator_api` unstable featureWedson Almeida Filho2024-04-161-0/+4
| | | | | | | | | | | | | | With the adoption of `BoxExt` and `VecExt`, we don't need the functions provided by this feature (namely the methods prefixed with `try_` and different allocator per collection instance). We do need `AllocError`, but we define our own as it is a trivial empty struct. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20240328013603.206764-11-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: introduce the `BoxExt` traitWedson Almeida Filho2024-04-161-0/+1
| | | | | | | | | | | | | | | | Make fallible versions of `new` and `new_uninit` methods available in `Box` even though it doesn't implement them because we build `alloc` with the `no_global_oom_handling` config. They also have an extra `flags` parameter that allows callers to pass flags to the allocator. Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Link: https://lore.kernel.org/r/20240328013603.206764-7-wedsonaf@gmail.com [ Used `Box::write()` to avoid one `unsafe` block as suggested by Boqun. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: introduce allocation flagsWedson Almeida Filho2024-04-161-0/+61
| | | | | | | | | | | We'll use them when allocating `Box`, `Arc`, and `UniqueArc` instances, as well as when allocating memory for `Vec` elements. These changes will come in subsequent patches. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20240328013603.206764-6-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: alloc: introduce the `VecExt` traitWedson Almeida Filho2024-04-161-0/+1
| | | | | | | | | | | | | | Make `try_with_capacity`, `try_push`, and `try_extend_from_slice` methods available in `Vec` even though it doesn't implement them. It is implemented with `try_reserve` and `push_within_capacity`. This is in preparation for switching to the upstream `alloc` crate. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Suggested-by: Gary Guo <gary@garyguo.net> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20240328013603.206764-3-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
* rust: kernel: move `allocator` module under `alloc`Wedson Almeida Filho2024-04-161-0/+7
We will add more to the `alloc` module in subsequent patches (e.g., allocation flags and extension traits). Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Wedson Almeida Filho <walmeida@microsoft.com> Link: https://lore.kernel.org/r/20240328013603.206764-2-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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