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2025-03-13rust: alloc: update module comment of alloc.rsDanilo Krummrich
commit 8ae740c3917ff92108df17236b3cf1b9a74bd359 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: implement `Cmalloc` in module allocator_testDanilo Krummrich
commit dd09538fb4093176a818fcecd45114430cc5840f upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: implement `contains` for `Flags`Danilo Krummrich
commit 909037ce0369bc3f4fd31743fd2d8d7096f06002 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: remove `VecExt` extensionDanilo Krummrich
commit 405966efc789888c3e1a53cd09d2c2b338064438 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: implement `IntoIterator` for `Vec`Danilo Krummrich
commit 1d1d223aa3b37c34271aefc2706340d0843bfcb2 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: implement kernel `Vec` typeDanilo Krummrich
commit 2aac4cd7dae3d7bb0e0ddec2561b2ee4cbe6c8f6 upstream. `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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: introduce `ArrayLayout`Benno Lossin
commit 9e7bbfa182767f638ba61dba3518ff78da9f31ff upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: remove extension of std's `Box`Danilo Krummrich
commit e8c6ccdbcaaf31f26c0fffd4073edd0b0147cdc6 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: implement kernel `Box`Danilo Krummrich
commit c8cfa8d0c0b10be216861fe904ea68978b1dcc97 upstream. `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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: add __GFP_NOWARN to `Flags`Danilo Krummrich
commit 01b2196e5aac8af9343282d0044fa0d6b07d484c upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: add module `allocator_test`Danilo Krummrich
commit 5a888c28e3b4ff6f54a53fca33951537d135e7f1 upstream. `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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: make `allocator` module publicDanilo Krummrich
commit a87a36f0bf517dae22f3e3790b05c979070f776a upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: implement `ReallocFunc`Danilo Krummrich
commit 8a799831fc63c988eec90d334fdd68ff5f2c7eb5 upstream. `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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-03-13rust: alloc: add `Allocator` traitDanilo Krummrich
commit b7a084ba4fbb8f416ce8d19c93a3a2bee63c9c89 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-07-08rust: add abstraction for `struct page`Alice Ryhl
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>
2024-07-08rust: alloc: add __GFP_HIGHMEM flagAlice Ryhl
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>
2024-07-08rust: alloc: fix typo in docs for GFP_NOWAITAlice Ryhl
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>
2024-05-05rust: kernel: remove redundant importsMiguel Ojeda
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>
2024-04-16rust: kernel: remove usage of `allocator_api` unstable featureWedson Almeida Filho
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>
2024-04-16rust: alloc: introduce the `BoxExt` traitWedson Almeida Filho
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>
2024-04-16rust: alloc: introduce allocation flagsWedson Almeida Filho
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>
2024-04-16rust: alloc: introduce the `VecExt` traitWedson Almeida Filho
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>
2024-04-16rust: kernel: move `allocator` module under `alloc`Wedson Almeida Filho
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>