pm24.git, branch rust-6.4

rust: ioctl: Add ioctl number manipulation functions

2023-04-21T23:46:45Z

Add simple 1:1 wrappers of the C ioctl number manipulation functions. Since these are macros we cannot bindgen them directly, and since they should be usable in const context we cannot use helper wrappers, so we'll have to reimplement them in Rust. Thankfully, the C headers do declare defines for the relevant bitfield positions, so we don't need to duplicate that. Signed-off-by: Asahi Lina Link: https://lore.kernel.org/r/20230329-rust-uapi-v2-2-bca5fb4d4a12@asahilina.net [ Moved the `#![allow(non_snake_case)]` to the usual place. ] Signed-off-by: Miguel Ojeda

rust: uapi: Add UAPI crate

2023-04-21T23:46:45Z

This crate mirrors the `bindings` crate, but will contain only UAPI bindings. Unlike the bindings crate, drivers may directly use this crate if they have to interface with userspace. Initially, just bind the generic ioctl stuff. In the future, we would also like to add additional checks to ensure that all types exposed by this crate satisfy UAPI-safety guarantees (that is, they are safely castable to/from a "bag of bits"). [ Miguel: added support for the `rustdoc` and `rusttest` targets, since otherwise they fail, and we want to keep them working. ] Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Asahi Lina Link: https://lore.kernel.org/r/20230329-rust-uapi-v2-1-bca5fb4d4a12@asahilina.net Signed-off-by: Miguel Ojeda

rust: sync: introduce `CondVar`

2023-04-21T23:46:45Z

This is the traditional condition variable or monitor synchronisation primitive. It is implemented with C's `wait_queue_head_t`. It allows users to release a lock and go to sleep while guaranteeing that notifications won't be missed. This is achieved by enqueuing a wait entry before releasing the lock. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Reviewed-by: Alice Ryhl Link: https://lore.kernel.org/r/20230411054543.21278-12-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda

rust: lock: add `Guard::do_unlocked`

2023-04-21T23:46:30Z

It releases the lock, executes some function provided by the caller, then reacquires the lock. This is preparation for the implementation of condvars, which will sleep after between unlocking and relocking. We need an explicit `relock` method for primitives like `SpinLock` that have an irqsave variant: we use the guard state to determine if the lock was originally acquired with the regular `lock` function or `lock_irqsave`. Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Link: https://lore.kernel.org/rust-for-linux/20230412121431.41627-1-wedsonaf@gmail.com/ [ Removed the irqsave bits as discussed. ] Signed-off-by: Miguel Ojeda

rust: sync: introduce `LockedBy`

2023-04-21T22:20:00Z

This allows us to have data protected by a lock despite not being wrapped by it. Access is granted by providing evidence that the lock is held by the caller. Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Reviewed-by: Benno Lossin Link: https://lore.kernel.org/r/20230411054543.21278-13-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda

rust: introduce `current`

2023-04-21T22:20:00Z

This allows Rust code to get a reference to the current task without having to increment the refcount, but still guaranteeing memory safety. Cc: Ingo Molnar Cc: Peter Zijlstra Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Link: https://lore.kernel.org/r/20230411054543.21278-10-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda

rust: add basic `Task`

2023-04-21T22:20:00Z

It is an abstraction for C's `struct task_struct`. It implements `AlwaysRefCounted`, so the refcount of the wrapped object is managed safely on the Rust side. Cc: Ingo Molnar Cc: Peter Zijlstra Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Link: https://lore.kernel.org/r/20230411054543.21278-9-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda

rust: introduce `ARef`

2023-04-21T22:20:00Z

This is an owned reference to an object that is always ref-counted. This is meant to be used in wrappers for C types that have their own ref counting functions, for example, tasks, files, inodes, dentries, etc. Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Reviewed-by: Gary Guo Link: https://lore.kernel.org/r/20230411054543.21278-8-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda

rust: lock: introduce `SpinLock`

2023-04-21T22:20:00Z

This is the `spinlock_t` lock backend and allows Rust code to use the kernel spinlock idiomatically. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Link: https://lore.kernel.org/r/20230419174426.132207-1-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda

rust: lock: introduce `Mutex`

2023-04-21T22:20:00Z

This is the `struct mutex` lock backend and allows Rust code to use the kernel mutex idiomatically. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Will Deacon Cc: Waiman Long Reviewed-by: Martin Rodriguez Reboredo Signed-off-by: Wedson Almeida Filho Link: https://lore.kernel.org/r/20230411054543.21278-3-wedsonaf@gmail.com Signed-off-by: Miguel Ojeda