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2025-02-21rust: kbuild: add -fzero-init-padding-bits to bindgen_skip_cflagsJustin M. Forbes
[ Upstream commit a9c621a217128eb3fb7522cf763992d9437fd5ba ] This seems to break the build when building with gcc15: Unable to generate bindings: ClangDiagnostic("error: unknown argument: '-fzero-init-padding-bits=all'\n") Thus skip that flag. Signed-off-by: Justin M. Forbes <jforbes@fedoraproject.org> Fixes: dce4aab8441d ("kbuild: Use -fzero-init-padding-bits=all") Reviewed-by: Kees Cook <kees@kernel.org> Link: https://lore.kernel.org/r/20250129215003.1736127-1-jforbes@fedoraproject.org [ Slightly reworded commit. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-21rust: rbtree: fix overindented list itemMiguel Ojeda
commit 2e4f982cf392af2f1282b5537a72144e064799e3 upstream. Starting with Rust 1.86.0 (to be released 2025-04-03), Clippy will have a new lint, `doc_overindented_list_items` [1], which catches cases of overindented list items. The lint has been added by Yutaro Ohno, based on feedback from the kernel [2] on a patch that fixed a similar case -- commit 0c5928deada1 ("rust: block: fix formatting in GenDisk doc"). Clippy reports a few cases in the kernel, apart from the one already fixed in the commit above. One is this one: error: doc list item overindented --> rust/kernel/rbtree.rs:1152:5 | 1152 | /// null, it is a pointer to the root of the [`RBTree`]. | ^^^^ help: try using ` ` (2 spaces) | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#doc_overindented_list_items = note: `-D clippy::doc-overindented-list-items` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(clippy::doc_overindented_list_items)]` Thus clean it up. Cc: Yutaro Ohno <yutaro.ono.418@gmail.com> Cc: stable@vger.kernel.org # Needed in 6.12.y and 6.13.y only (Rust is pinned in older LTSs). Fixes: a335e9591404 ("rust: rbtree: add `RBTree::entry`") Link: https://github.com/rust-lang/rust-clippy/pull/13711 [1] Link: https://github.com/rust-lang/rust-clippy/issues/13601 [2] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Yutaro Ohno <yutaro.ono.418@gmail.com> Link: https://lore.kernel.org/r/20250206232022.599998-1-ojeda@kernel.org [ There are a few other cases, so updated message. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-17rust: init: use explicit ABI to clean warning in future compilersMiguel Ojeda
commit c21bdb3d8a850afdfa4afe77eea39ae9533629b0 upstream. Starting with Rust 1.86.0 (currently in nightly, to be released on 2025-04-03), the `missing_abi` lint is warn-by-default [1]: error: extern declarations without an explicit ABI are deprecated --> rust/doctests_kernel_generated.rs:3158:1 | 3158 | extern { | ^^^^^^ help: explicitly specify the C ABI: `extern "C"` | = note: `-D missing-abi` implied by `-D warnings` = help: to override `-D warnings` add `#[allow(missing_abi)]` Thus clean it up. Cc: <stable@vger.kernel.org> # Needed in 6.12.y and 6.13.y only (Rust is pinned in older LTSs). Fixes: 7f8977a7fe6d ("rust: init: add `{pin_}chain` functions to `{Pin}Init<T, E>`") Link: https://github.com/rust-lang/rust/pull/132397 [1] 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/20250121200934.222075-1-ojeda@kernel.org [ Added 6.13.y to Cc: stable tag. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-19rust: kbuild: set `bindgen`'s Rust target versionMiguel Ojeda
commit 7a5f93ea5862da91488975acaa0c7abd508f192b upstream. Each `bindgen` release may upgrade the list of Rust targets. For instance, currently, in their master branch [1], the latest ones are: Nightly => { vectorcall_abi: #124485, ptr_metadata: #81513, layout_for_ptr: #69835, }, Stable_1_77(77) => { offset_of: #106655 }, Stable_1_73(73) => { thiscall_abi: #42202 }, Stable_1_71(71) => { c_unwind_abi: #106075 }, Stable_1_68(68) => { abi_efiapi: #105795 }, By default, the highest stable release in their list is used, and users are expected to set one if they need to support older Rust versions (e.g. see [2]). Thus, over time, new Rust features are used by default, and at some point, it is likely that `bindgen` will emit Rust code that requires a Rust version higher than our minimum (or perhaps enabling an unstable feature). Currently, there is no problem because the maximum they have, as seen above, is Rust 1.77.0, and our current minimum is Rust 1.78.0. Therefore, set a Rust target explicitly now to prevent going forward in time too much and thus getting potential build failures at some point. Since we also support a minimum `bindgen` version, and since `bindgen` does not support passing unknown Rust target versions, we need to use the list of our minimum `bindgen` version, rather than the latest. So, since `bindgen` 0.65.1 had this list [3], we need to use Rust 1.68.0: /// Rust stable 1.64 /// * `core_ffi_c` ([Tracking issue](https://github.com/rust-lang/rust/issues/94501)) => Stable_1_64 => 1.64; /// Rust stable 1.68 /// * `abi_efiapi` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/65815)) => Stable_1_68 => 1.68; /// Nightly rust /// * `thiscall` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/42202)) /// * `vectorcall` calling convention (no tracking issue) /// * `c_unwind` calling convention ([Tracking issue](https://github.com/rust-lang/rust/issues/74990)) => Nightly => nightly; ... /// Latest stable release of Rust pub const LATEST_STABLE_RUST: RustTarget = RustTarget::Stable_1_68; Thus add the `--rust-target 1.68` parameter. Add a comment as well explaining this. An alternative would be to use the currently running (i.e. actual) `rustc` and `bindgen` versions to pick a "better" Rust target version. However, that would introduce more moving parts depending on the user setup and is also more complex to implement. Starting with `bindgen` 0.71.0 [4], we will be able to set any future Rust version instead, i.e. we will be able to set here our minimum supported Rust version. Christian implemented it [5] after seeing this patch. Thanks! Cc: Christian Poveda <git@pvdrz.com> Cc: Emilio Cobos Álvarez <emilio@crisal.io> Cc: stable@vger.kernel.org # needed for 6.12.y; unneeded for 6.6.y; do not apply to 6.1.y Fixes: c844fa64a2d4 ("rust: start supporting several `bindgen` versions") Link: https://github.com/rust-lang/rust-bindgen/blob/21c60f473f4e824d4aa9b2b508056320d474b110/bindgen/features.rs#L97-L105 [1] Link: https://github.com/rust-lang/rust-bindgen/issues/2960 [2] Link: https://github.com/rust-lang/rust-bindgen/blob/7d243056d335fdc4537f7bca73c06d01aae24ddc/bindgen/features.rs#L131-L150 [3] Link: https://github.com/rust-lang/rust-bindgen/blob/main/CHANGELOG.md#0710-2024-12-06 [4] Link: https://github.com/rust-lang/rust-bindgen/pull/2993 [5] Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20241123180323.255997-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14rust: enable arbitrary_self_types and remove `Receiver`Gary Guo
commit c95bbb59a9b22f9b838b15d28319185c1c884329 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-05rust: block: fix formatting of `kernel::block::mq::request` moduleFrancesco Zardi
[ Upstream commit 28e848386b92645f93b9f2fdba5882c3ca7fb3e2 ] Fix several issues with rustdoc formatting for the `kernel::block::mq::Request` module, in particular: - An ordered list not rendering correctly, fixed by using numbers prefixes instead of letters. - Code snippets formatted as regular text, fixed by wrapping the code with `back-ticks`. - References to types missing intra-doc links, fixed by wrapping the types with [square brackets]. Reported-by: Miguel Ojeda <ojeda@kernel.org> Closes: https://github.com/Rust-for-Linux/linux/issues/1108 Signed-off-by: Francesco Zardi <frazar00@gmail.com> Acked-by: Andreas Hindborg <a.hindborg@kernel.org> Fixes: 3253aba3408a ("rust: block: introduce `kernel::block::mq` module") Link: https://lore.kernel.org/r/20240903173027.16732-3-frazar00@gmail.com [ Added an extra intra-doc link. Took the chance to add some periods for consistency. Reworded slightly. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rust: macros: fix documentation of the paste! macroPaolo Bonzini
[ Upstream commit 15541c9263ce34ff95a06bc68f45d9bc5c990bcd ] One of the example in this section uses a curious mix of the constant and function declaration syntaxes; fix it. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Fixes: 823d4737d4c2 ("rust: macros: add `paste!` proc macro") Link: https://lore.kernel.org/r/20241019072208.1016707-1-pbonzini@redhat.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rust: kernel: fix THIS_MODULE header path in ThisModule doc commentYutaro Ohno
[ Upstream commit 8b55dc8610acf816a66373be53ca6e3bbe2d313a ] The doc comment for `ThisModule` incorrectly states the C header file for `THIS_MODULE` as `include/linux/export.h`, while the correct path is `include/linux/init.h`. This is because `THIS_MODULE` was moved in commit 5b20755b7780 ("init: move THIS_MODULE from <linux/export.h> to <linux/init.h>"). Update the doc comment for `ThisModule` to reflect the correct header file path for `THIS_MODULE`. Fixes: 5b20755b7780 ("init: move THIS_MODULE from <linux/export.h> to <linux/init.h>") Signed-off-by: Yutaro Ohno <yutaro.ono.418@gmail.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/ZxXDZwxWgoEiIYkj@ohnotp Signed-off-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rust: rbtree: fix `SAFETY` comments that should be `# Safety` sectionsMiguel Ojeda
[ Upstream commit 8333ff4d0799aafbe4275cddcbaf45e545e4efba ] 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> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-05rust: helpers: Avoid raw_spin_lock initialization for PREEMPT_RTEder Zulian
[ Upstream commit 5c2e7736e20d9b348a44cafbfa639fe2653fbc34 ] When PREEMPT_RT=y, spin locks are mapped to rt_mutex types, so using spinlock_check() + __raw_spin_lock_init() to initialize spin locks is incorrect, and would cause build errors. Introduce __spin_lock_init() to initialize a spin lock with lockdep rquired information for PREEMPT_RT builds, and use it in the Rust helper. Fixes: d2d6422f8bd1 ("x86: Allow to enable PREEMPT_RT.") Closes: https://lore.kernel.org/oe-kbuild-all/202409251238.vetlgXE9-lkp@intel.com/ Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Eder Zulian <ezulian@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Tested-by: Boqun Feng <boqun.feng@gmail.com> Link: https://lore.kernel.org/r/20241107163223.2092690-2-ezulian@redhat.com Signed-off-by: Sasha Levin <sashal@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
2024-10-03rust: 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>
2024-09-26rust: mutex: fix __mutex_init() usage in case of PREEMPT_RTDirk Behme
In case CONFIG_PREEMPT_RT is enabled __mutex_init() becomes a macro instead of an extern function (simplified from include/linux/mutex.h): #ifndef CONFIG_PREEMPT_RT extern void __mutex_init(struct mutex *lock, const char *name, struct lock_class_key *key); #else #define __mutex_init(mutex, name, key) \ do { \ rt_mutex_base_init(&(mutex)->rtmutex); \ __mutex_rt_init((mutex), name, key); \ } while (0) #endif The macro isn't resolved by bindgen, then. What results in a build error: error[E0425]: cannot find function `__mutex_init` in crate `bindings` --> rust/kernel/sync/lock/mutex.rs:104:28 | 104 | unsafe { bindings::__mutex_init(ptr, name, key) } | ^^^^^^^^^^^^ help: a function with a similar name exists: `__mutex_rt_init` | ::: rust/bindings/bindings_generated.rs:23722:5 | 23722 | / pub fn __mutex_rt_init( 23723 | | lock: *mut mutex, 23724 | | name: *const core::ffi::c_char, 23725 | | key: *mut lock_class_key, 23726 | | ); | |_____- similarly named function `__mutex_rt_init` defined here Fix this by adding a helper. As explained by Gary Guo in [1] no #ifdef CONFIG_PREEMPT_RT is needed here as rust/bindings/lib.rs prefers externed function to helpers if an externed function exists. Reported-by: Conor Dooley <conor@kernel.org> Link: https://lore.kernel.org/rust-for-linux/20240913-shack-estate-b376a65921b1@spud/ Link: https://lore.kernel.org/rust-for-linux/20240915123626.1a170103.gary@garyguo.net/ [1] Fixes: 6d20d629c6d8 ("rust: lock: introduce `Mutex`") Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com> Tested-by: Conor Dooley <conor.dooley@microchip.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240916073752.3123484-1-dirk.behme@de.bosch.com [ Reworded to include the proper example by Dirk. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-26rust: fix `ARCH_SLAB_MINALIGN` multiple definition errorGary Guo
We use const helpers in form of const size_t RUST_CONST_HELPER_ARCH_SLAB_MINALIGN = ARCH_SLAB_MINALIGN; to aid generation of constants by bindgen because it is otherwise a macro definition of an expression and bindgen doesn't expand the constant. The helpers are then have `RUST_CONST_HELPER` prefix stripped and exposed to Rust code as if `ARCH_SLAB_MISALIGN` is generated natively by bindgen. This works well for most constants, but on RISC-V, `ARCH_SLAB_MINALIGN` is defined directly as literal constant if `!CONFIG_MMU`, and bindgen would generate `ARCH_SLAB_MINALIGN` directly, thus conflict with the one generated through the helper. To fix this, we simply need to block bindgen from generating directly without going through helper. Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202409160804.eSg9zh1e-lkp@intel.com/ Signed-off-by: Gary Guo <gary@garyguo.net> Reviewed-by: Christian Schrefl <chrisi.schrefl@gmail.com> Link: https://lore.kernel.org/r/20240916003347.1744345-1-gary@garyguo.net Signed-off-by: Miguel Ojeda <ojeda@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 ...
2024-09-16rust: cfi: add support for CFI_CLANG with RustMatthew Maurer
Make it possible to use the Control Flow Integrity (CFI) sanitizer when Rust is enabled. Enabling CFI with Rust requires that CFI is configured to normalize integer types so that all integer types of the same size and signedness are compatible under CFI. Rust and C use the same LLVM backend for code generation, so Rust KCFI is compatible with the KCFI used in the kernel for C. In the case of FineIBT, CFI also depends on -Zpatchable-function-entry for rewriting the function prologue, so we set that flag for Rust as well. The flag for FineIBT requires rustc 1.80.0 or later, so include a Kconfig requirement for that. Enabling Rust will select CFI_ICALL_NORMALIZE_INTEGERS because the flag is required to use Rust with CFI. Using select rather than `depends on` avoids the case where Rust is not visible in menuconfig due to CFI_ICALL_NORMALIZE_INTEGERS not being enabled. One disadvantage of select is that RUST must `depends on` all of the things that CFI_ICALL_NORMALIZE_INTEGERS depends on to avoid invalid configurations. Alice has been using KCFI on her phone for several months, so it is reasonably well tested on arm64. Signed-off-by: Matthew Maurer <mmaurer@google.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Sami Tolvanen <samitolvanen@google.com> Tested-by: Gatlin Newhouse <gatlin.newhouse@gmail.com> Acked-by: Kees Cook <kees@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20240801-kcfi-v2-2-c93caed3d121@google.com [ Replaced `!FINEIBT` requirement with `!CALL_PADDING` to prevent a build error on older Rust compilers. Fixed typo. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
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>
2024-09-05kbuild: rust: replace proc macros dependency on `core.o` with the version textMiguel Ojeda
With the `RUSTC_VERSION_TEXT` rebuild support in place, now proc macros can depend on that instead of `core.o`. This means that both the `core` and `macros` crates can be built in parallel, and that touching `core.o` does not trigger a rebuild of the proc macros. This could be accomplished using the same approach as for `core` (i.e. depending directly on `include/config/RUSTC_VERSION_TEXT`). However, that is considered an implementation detail [1], and thus it is best to avoid it. Instead, let fixdep find a string that we explicitly write down in the source code for this purpose (like it is done for `include/linux/compiler-version.h`), which we can easily do (unlike for `core`) since this is our own source code. Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/rust-for-linux/CAK7LNAQBG0nDupXSgAAk-6nOqeqGVkr3H1RjYaqRJ1OxmLm6xA@mail.gmail.com/ [1] Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Alice Ryhl <aliceryhl@google.com> Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20240902165535.1101978-5-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-09-05kbuild: rust: rebuild if the version text changesMiguel Ojeda
Now that `RUSTC_VERSION_TEXT` exists, use it to rebuild `core` when the version text changes (which in turn will trigger a rebuild of all the kernel Rust code). This also applies to proc macros (which only work with the `rustc` that compiled them), via the already existing dependency on `core.o`. That is cleaned up in the next commit. However, this does not cover host programs written in Rust, which is the same case in the C side. This is accomplished by referencing directly the generated file, instead of using the `fixdep` header trick, since we cannot change the Rust standard library sources. This is not too much of a burden, since it only needs to be done for `core`. Tested-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://lore.kernel.org/r/20240902165535.1101978-4-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@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>
2024-09-02rust: macros: provide correct provenance when constructing THIS_MODULEBoqun Feng
Currently while defining `THIS_MODULE` symbol in `module!()`, the pointer used to construct `ThisModule` is derived from an immutable reference of `__this_module`, which means the pointer doesn't have the provenance for writing, and that means any write to that pointer is UB regardless of data races or not. However, the usage of `THIS_MODULE` includes passing this pointer to functions that may write to it (probably in unsafe code), and this will create soundness issues. One way to fix this is using `addr_of_mut!()` but that requires the unstable feature "const_mut_refs". So instead of `addr_of_mut()!`, an extern static `Opaque` is used here: since `Opaque<T>` is transparent to `T`, an extern static `Opaque` will just wrap the C symbol (defined in a C compile unit) in an `Opaque`, which provides a pointer with writable provenance via `Opaque::get()`. This fix the potential UBs because of pointer provenance unmatched. Reported-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Gary Guo <gary@garyguo.net> Closes: https://rust-for-linux.zulipchat.com/#narrow/stream/x/topic/x/near/465412664 Fixes: 1fbde52bde73 ("rust: add `macros` crate") Cc: stable@vger.kernel.org # 6.6.x: be2ca1e03965: ("rust: types: Make Opaque::get const") Link: https://lore.kernel.org/r/20240828180129.4046355-1-boqun.feng@gmail.com [ Fixed two typos, reworded title. - Miguel ] 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>
2024-08-31rust: rbtree: add cursorMatt Gilbride
Add a cursor interface to `RBTree`, supporting the following use cases: - Inspect the current node pointed to by the cursor, inspect/move to it's neighbors in sort order (bidirectionally). - Mutate the tree itself by removing the current node pointed to by the cursor, or one of its neighbors. Add functions to obtain a cursor to the tree by key: - The node with the smallest key - The node with the largest key - The node matching the given key, or the one with the next larger key The cursor abstraction is needed by the binder driver to efficiently search for nodes and (conditionally) modify them, as well as their neighbors [1]. Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-6-08ba9197f637@google.com/ [1] Co-developed-by: Alice Ryhl <aliceryhl@google.com> 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-v12-4-014561758a57@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-31rust: rbtree: add mutable iteratorWedson Almeida Filho
Add mutable Iterator implementation for `RBTree`, allowing iteration over (key, value) pairs in key order. Only values are mutable, as mutating keys implies modifying a node's position in the tree. Mutable iteration is used by the binder driver during shutdown to clean up the tree maintained by the "range allocator" [1]. Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-6-08ba9197f637@google.com/ [1] Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-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-v12-3-014561758a57@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-31rust: rbtree: add iteratorWedson Almeida Filho
- Add Iterator implementation for `RBTree`, allowing iteration over (key, value) pairs in key order. - Add individual `keys()` and `values()` functions to iterate over keys or values alone. - Update doctests to use iteration instead of explicitly getting items. Iteration is needed by the binder driver to enumerate all values in a tree for oneway spam detection [1]. Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-17-08ba9197f637@google.com/ [1] Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Tested-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Matt Gilbride <mattgilbride@google.com> Link: https://lore.kernel.org/r/20240822-b4-rbtree-v12-2-014561758a57@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-31rust: rbtree: add red-black tree implementation backed by the C versionWedson Almeida Filho
The rust rbtree exposes a map-like interface over keys and values, backed by the kernel red-black tree implementation. Values can be inserted, deleted, and retrieved from a `RBTree` by key. This base abstraction is used by binder to store key/value pairs and perform lookups, for example the patch "[PATCH RFC 03/20] rust_binder: add threading support" in the binder RFC [1]. Link: https://lore.kernel.org/rust-for-linux/20231101-rust-binder-v1-3-08ba9197f637@google.com/ [1] Signed-off-by: Wedson Almeida Filho <wedsonaf@gmail.com> Reviewed-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-v12-1-014561758a57@google.com [ Updated link to docs.kernel.org. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-30rust: net::phy unified genphy_read_status function for C22 and C45 registersFUJITA Tomonori
Add unified genphy_read_status function for C22 and C45 registers. Instead of having genphy_c22 and genphy_c45 methods, this unifies genphy_read_status functions for C22 and C45. Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-30rust: net::phy unified read/write API for C22 and C45 registersFUJITA Tomonori
Add the unified read/write API for C22 and C45 registers. The abstractions support access to only C22 registers now. Instead of adding read/write_c45 methods specifically for C45, a new reg module supports the unified API to access C22 and C45 registers with trait, by calling an appropriate phylib functions. Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-30rust: net::phy implement AsRef<kernel::device::Device> traitFUJITA Tomonori
Implement AsRef<kernel::device::Device> trait for Device. A PHY driver needs a reference to device::Device to call the firmware API. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Trevor Gross <tmgross@umich.edu> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-30rust: net::phy support probe callbackFUJITA Tomonori
Support phy_driver probe callback, used to set up device-specific structures. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Trevor Gross <tmgross@umich.edu> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-30rust: sizes: add commonly used constantsFUJITA Tomonori
Add rust equivalent to include/linux/sizes.h, makes code more readable. Only SZ_*K that QT2025 PHY driver uses are added. Make generated constants accessible with a proper type. Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Reviewed-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Trevor Gross <tmgross@umich.edu> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2024-08-27rust: alloc: eschew `Box<MaybeUninit<T>>::write`Jubilee Young
Upstream Rust's libs-api team has consensus for stabilizing some of `feature(new_uninit)`, but not for `Box<MaybeUninit<T>>::write`. Instead, we can use `MaybeUninit<T>::write`, so Rust for Linux can drop the feature after stabilization. That will happen after merging, as the FCP has completed [1]. This is required before stabilization because remaining-unstable API will be divided into new features. This code doesn't know about those yet. It can't: they haven't landed, as the relevant PR is blocked on rustc's CI testing Rust-for-Linux without this patch. [ The PR has landed [2] and will be released in Rust 1.82.0 (expected on 2024-10-17), so we could conditionally enable the new unstable feature (`box_uninit_write` [3]) instead, but just for a single `unsafe` block it is probably not worth it. For the time being, I added it to the "nice to have" section of our unstable features list. - Miguel ] Link: https://github.com/rust-lang/rust/issues/63291#issuecomment-2183022955 [1] Link: https://github.com/rust-lang/rust/pull/129416 [2] Link: https://github.com/rust-lang/rust/issues/129397 [3] Signed-off-by: Jubilee Young <workingjubilee@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Trevor Gross <tmgross@umich.edu> [ Reworded slightly. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-25rust: enable rustdoc's `--generate-link-to-definition`Miguel Ojeda
In Rust 1.56.0 [1], rustdoc introduced the "jump to definition" feature [2], i.e. the unstable flag `--generate-link-to-definition`. It adds links to the source view of the documentation. For instance, in the source view of `rust/kernel/sync.rs`, for this code: impl Default for LockClassKey { fn default() -> Self { Self::new() } } It will add three hyperlinks: - `Default` points to the rendered "Trait `core::default::Default`" page (not the source view, since it goes to another crate, though this may change). - `LockClassKey` points to the `pub struct LockClassKey(...);` line in the same page, highlighting the line number. - `Self::new()` points to the `pub const fn new() -> Self { ... }` associated function, highlighting its line numbers (i.e. for the full function). This makes the source view more useful and a bit closer to the experience in e.g. the Elixir Cross Referencer [3]. I have provisionally enabled it for rust.docs.kernel.org [4] -- one can take a look at the source view there for an example of how it looks like. Thus enable it. Cc: Guillaume Gomez <guillaume1.gomez@gmail.com> Link: https://github.com/rust-lang/rust/pull/84176 [1] Link: https://github.com/rust-lang/rust/issues/89095 [2] Link: https://elixir.bootlin.com [3] Link: https://rust.docs.kernel.org [4] Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240818141249.387166-1-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-25rust: types: add `ARef::into_raw`Kartik Prajapati
Add a method for `ARef` that is analogous to `Arc::into_raw`. It is the inverse operation of `ARef::from_raw`, and allows you to convert the `ARef` back into a raw pointer while retaining ownership of the refcount. This new function will be used by [1] for converting the type in an `ARef` using `ARef::from_raw(ARef::into_raw(me).cast())`. Alice has also needed the same function for other use-cases in the past, but [1] is the first to go upstream. This was implemented independently by Kartik and Alice. The two versions were merged by Alice, so all mistakes are Alice's. Link: https://lore.kernel.org/r/20240801-vma-v3-1-db6c1c0afda9@google.com [1] Link: https://github.com/Rust-for-Linux/linux/issues/1044 Signed-off-by: Kartik Prajapati <kartikprajapati987@gmail.com> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Benno Lossin <benno.lossin@proton.me> [ Reworded to correct the author reference and changed tag to Link since it is not a bug. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-25rust: kernel: use docs.kernel.org links in code documentationMichael Vetter
Use links to docs.kernel.org instead of www.kernel.org/doc/html/latest in the code documentation. The links are shorter and cleaner. Link: https://github.com/Rust-for-Linux/linux/issues/1101 Signed-off-by: Michael Vetter <jubalh@iodoru.org> [ Reworded slightly. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add ListArcFieldAlice Ryhl
One way to explain what `ListArc` does is that it controls exclusive access to the prev/next pointer field in a refcounted object. The feature of having a special reference to a refcounted object with exclusive access to specific fields is useful for other things, so provide a general utility for that. This is used by Rust Binder to keep track of which processes have a reference to a given node. This involves an object for each process/node pair, that is referenced by both the process and the node. For some fields in this object, only the process's reference needs to access them (and it needs mutable access), so Binder uses a ListArc to give the process's reference exclusive access. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-10-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: support heterogeneous listsAlice Ryhl
Support linked lists that can hold many different structs at once. This is generally done using trait objects. The main challenge is figuring what the struct is given only a pointer to the ListLinks. We do this by storing a pointer to the struct next to the ListLinks field. The container_of operation will then just read that pointer. When the type is a trait object, that pointer will be a fat pointer whose metadata is a vtable that tells you what kind of struct it is. Heterogeneous lists are heavily used by Rust Binder. There are a lot of so-called todo lists containing various events that need to be delivered to userspace next time userspace calls into the driver. And there are quite a few different todo item types: incoming transaction, changes to refcounts, death notifications, and more. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-9-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add cursorAlice Ryhl
The cursor is very similar to the list iterator, but it has one important feature that the iterator doesn't: it can be used to remove items from the linked list. This feature cannot be added to the iterator because the references you get from the iterator are considered borrows of the original list, rather than borrows of the iterator. This means that there's no way to prevent code like this: let item = iter.next(); iter.remove(); use(item); If `iter` was a cursor instead of an iterator, then `item` will be considered a borrow of `iter`. Since `remove` destroys `iter`, this means that the borrow-checker will prevent uses of `item` after the call to `remove`. So there is a trade-off between supporting use in traditional for loops, and supporting removal of elements as you iterate. Iterators and cursors represents two different choices on that spectrum. Rust Binder needs cursors for the list of death notifications that a process is currently handling. When userspace tells Binder that it has finished processing the death notification, Binder will iterate the list to search for the relevant item and remove it. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-8-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add iteratorsAlice Ryhl
Rust Binder has lists containing stuff such as all contexts or all processes, and sometimes needs to iterate over them. This patch enables Rust Binder to do that using a normal for loop. The iterator returns the ArcBorrow type, so it is possible to grab a refcount to values while iterating. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-7-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add ListAlice Ryhl
Add the actual linked list itself. The linked list uses the following design: The List type itself just has a single pointer to the first element of the list. And the actual list items then form a cycle. So the last item is `first->prev`. This is slightly different from the usual kernel linked list. Matching that exactly would amount to giving List two pointers, and having it be part of the cycle of items. This alternate design has the advantage that the cycle is never completely empty, which can reduce the number of branches in some cases. However, it also has the disadvantage that List must be pinned, which this design is trying to avoid. Having the list items form a cycle rather than having null pointers at the beginning/end is convenient for several reasons. For one, it lets us store only one pointer in List, and it simplifies the implementation of several functions. Unfortunately, the `remove` function that removes an arbitrary element from the list has to be unsafe. This is needed because there is no way to handle the case where you pass an element from the wrong list. For example, if it is the first element of some other list, then that other list's `first` pointer would not be updated. Similarly, it could be a data race if you try to remove it from two different lists in parallel. (There's no problem with passing `remove` an item that's not in any list. Additionally, other removal methods such as `pop_front` need not be unsafe, as they can't be used to remove items from another list.) A future patch in this series will introduce support for cursors that can be used to remove arbitrary items without unsafe code. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-6-f5f5e8075da0@google.com [ Fixed a few typos. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add macro for implementing ListItemAlice Ryhl
Adds a macro for safely implementing the ListItem trait. As part of the implementation of the macro, we also provide a HasListLinks trait similar to the workqueue's HasWorkItem trait. The HasListLinks trait is only necessary if you are implementing ListItem using the impl_list_item macro. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-5-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add struct with prev/next pointersAlice Ryhl
Define the ListLinks struct, which wraps the prev/next pointers that will be used to insert values into a List in a future patch. Also define the ListItem trait, which is implemented by structs that have a ListLinks field. The ListItem trait provides four different methods that are all essentially container_of or the reverse of container_of. Two of them are used before inserting/after removing an item from the list, and the two others are used when looking at a value without changing whether it is in a list. This distinction is introduced because it is needed for the patch that adds support for heterogeneous lists, which are implemented by adding a third pointer field with a fat pointer to the full struct. When inserting into the heterogeneous list, the pointer-to-self is updated to have the right vtable, and the container_of operation is implemented by just returning that pointer instead of using the real container_of operation. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-4-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add tracking for ListArcAlice Ryhl
Add the ability to track whether a ListArc exists for a given value, allowing for the creation of ListArcs without going through UniqueArc. The `impl_list_arc_safe!` macro is extended with a `tracked_by` strategy that defers the tracking of ListArcs to a field of the struct. Additionally, the AtomicListArcTracker type is introduced, which can track whether a ListArc exists using an atomic. By deferring the tracking to a field of type AtomicListArcTracker, structs gain the ability to create ListArcs without going through a UniqueArc. Rust Binder uses this for some objects where we want to be able to insert them into a linked list at any time. Using the AtomicListArcTracker, we are able to check whether an item is already in the list, and if not, we can create a `ListArc` and push it. The macro has the ability to defer the tracking of ListArcs to a field, using whatever strategy that field has. Since we don't add any strategies other than AtomicListArcTracker, another similar option would be to hard-code that the field should be an AtomicListArcTracker. However, Rust Binder has a case where the AtomicListArcTracker is not stored directly in the struct, but in a sub-struct. Furthermore, the outer struct is generic: struct Wrapper<T: ?Sized> { links: ListLinks, inner: T, } Here, the Wrapper struct implements ListArcSafe with `tracked_by inner`, and then the various types used with `inner` also uses the macro to implement ListArcSafe. Some of them use the untracked strategy, and some of them use tracked_by with an AtomicListArcTracker. This way, Wrapper just inherits whichever choice `inner` has made. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-3-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: list: add ListArcAlice Ryhl
The `ListArc` type can be thought of as a special reference to a refcounted object that owns the permission to manipulate the `next`/`prev` pointers stored in the refcounted object. By ensuring that each object has only one `ListArc` reference, the owner of that reference is assured exclusive access to the `next`/`prev` pointers. When a `ListArc` is inserted into a `List`, the `List` takes ownership of the `ListArc` reference. There are various strategies for ensuring that a value has only one `ListArc` reference. The simplest is to convert a `UniqueArc` into a `ListArc`. However, the refcounted object could also keep track of whether a `ListArc` exists using a boolean, which could allow for the creation of new `ListArc` references from an `Arc` reference. Whatever strategy is used, the relevant tracking is referred to as "the tracking inside `T`", and the `ListArcSafe` trait (and its subtraits) are used to update the tracking when a `ListArc` is created or destroyed. Note that we allow the case where the tracking inside `T` thinks that a `ListArc` exists, but actually, there isn't a `ListArc`. However, we do not allow the opposite situation where a `ListArc` exists, but the tracking thinks it doesn't. This is because the former can at most result in us failing to create a `ListArc` when the operation could succeed, whereas the latter can result in the creation of two `ListArc` references. Only the latter situation can lead to memory safety issues. This patch introduces the `impl_list_arc_safe!` macro that allows you to implement `ListArcSafe` for types using the strategy where a `ListArc` can only be created from a `UniqueArc`. Other strategies are introduced in later patches. This is part of the linked list that Rust Binder will use for many different things. The strategy where a `ListArc` can only be created from a `UniqueArc` is actually sufficient for most of the objects that Rust Binder needs to insert into linked lists. Usually, these are todo items that are created and then immediately inserted into a queue. The const generic ID allows objects to have several prev/next pointer pairs so that the same object can be inserted into several different lists. You are able to have several `ListArc` references as long as they correspond to different pointer pairs. The ID itself is purely a compile-time concept and will not be present in the final binary. Both the `List` and the `ListArc` will need to agree on the ID for them to work together. Rust Binder uses this in a few places (e.g. death recipients) where the same object can be inserted into both generic todo lists and some other lists for tracking the status of the object. The ID is a const generic rather than a type parameter because the `pair_from_unique` method needs to be able to assert that the two ids are different. There's no easy way to assert that when using types instead of integers. Reviewed-by: Benno Lossin <benno.lossin@proton.me> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-2-f5f5e8075da0@google.com Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-23rust: init: add `assert_pinned` macroBenno Lossin
Add a macro to statically check if a field of a struct is marked with `#[pin]` ie that it is structurally pinned. This can be used when `unsafe` code needs to rely on fields being structurally pinned. The macro has a special "inline" mode for the case where the type depends on generic parameters from the surrounding scope. Signed-off-by: Benno Lossin <benno.lossin@proton.me> Co-developed-by: Alice Ryhl <aliceryhl@google.com> Signed-off-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240814-linked-list-v5-1-f5f5e8075da0@google.com [ Replaced `compile_fail` with `ignore` and a TODO note. Removed `pub` from example to clean `unreachable_pub` lint. - Miguel ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-22rust: init: add `write_[pin_]init` functionsBenno Lossin
Sometimes it is necessary to split allocation and initialization into two steps. One such situation is when reusing existing allocations obtained via `Box::drop_contents`. See [1] for an example. In order to support this use case add `write_[pin_]init` functions to the pin-init API. These functions operate on already allocated smart pointers that wrap `MaybeUninit<T>`. Link: https://lore.kernel.org/rust-for-linux/f026532f-8594-4f18-9aa5-57ad3f5bc592@proton.me/ [1] Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Reviewed-by: Gary Guo <gary@garyguo.net> Link: https://lore.kernel.org/r/20240819112415.99810-2-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-08-22rust: kernel: add `drop_contents` to `BoxExt`Benno Lossin
Sometimes (see [1]) it is necessary to drop the value inside of a `Box<T>`, but retain the allocation. For example to reuse the allocation in the future. Introduce a new function `drop_contents` that turns a `Box<T>` into `Box<MaybeUninit<T>>` by dropping the value. Link: https://lore.kernel.org/rust-for-linux/20240418-b4-rbtree-v3-5-323e134390ce@google.com/ [1] Signed-off-by: Benno Lossin <benno.lossin@proton.me> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Reviewed-by: Alice Ryhl <aliceryhl@google.com> Link: https://lore.kernel.org/r/20240819112415.99810-1-benno.lossin@proton.me Signed-off-by: Miguel Ojeda <ojeda@kernel.org>