From patchwork Thu Dec 5 14:14:32 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895426 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1A95A17579; Thu, 5 Dec 2024 14:15:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408154; cv=none; b=SfCyAFi56zsYGJj8edbGzT1vAisVM1cpxc4mjQ8vWJXm/XC6ZslaUs6qZM4pZL1Uvh2Z8CuzcFI3oHvnpKIkEPFPjq8HGU1G5ZLSiPnqt2vws77uF2wbJ8znaoHmhJXyc333RsjsZXAeN/7fAe3l8/7iobDvVb6u0+ei9+hENH8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408154; c=relaxed/simple; bh=KzaLlrMOSYV96pirchpaX9zp5w3CHhhYNXDvSJp4QvQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BqCcmpqbrH5FGD3SM3pjR3YuQUrRq8TfaHefxMhl8ePuHoT4BQnEz3GjZ+8xvxYUEotNHXospZq4NJ5VpnvjLU5wb4PFMsgrE7288ZwzAxPrxJI4SULSTSQTH9hgSlHfmrXsIqO7dFrz9YsOV3JYW3U9z3eraKePOB0GQKqUBdo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=IGBaFtCo; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="IGBaFtCo" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D03DC4CEDC; Thu, 5 Dec 2024 14:15:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408153; bh=KzaLlrMOSYV96pirchpaX9zp5w3CHhhYNXDvSJp4QvQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IGBaFtCowUHZdIlxpTOCKXngVKHdfZBRRuPJaJmFyLMSPv6ziFnPg7v1pKpci/73F +5tSuAup0lPU7CwUunY8LozDOOXIcvqRBsoUd09B1Sp5UDi5LPsxrpZZgjBYdDt8l9 5f3T7tqJOuNeLk4AASZ9tdfSXpZgwVKioaS6LTNCeGUuNkIbTysfOh+WK+YXBDAo2/ LYF1RCv67QACacIcR9moO0M5E4uObzBZHPtNXFUeCDzcqyfzH2IdO3FJtXbrPtEtpl 7HRHaQFASh/AfvqV7AJgz8nXGWNGw3I/I3ZFRyuaBWvyPCaDLQBx2DKX5wSqYW1zUz lCWJUlIK4gnZw== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 01/13] rust: pass module name to `Module::init` Date: Thu, 5 Dec 2024 15:14:32 +0100 Message-ID: <20241205141533.111830-2-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In a subsequent patch we introduce the `Registration` abstraction used to register driver structures. Some subsystems require the module name on driver registration (e.g. PCI in __pci_register_driver()), hence pass the module name to `Module::init`. Signed-off-by: Danilo Krummrich --- drivers/block/rnull.rs | 2 +- rust/kernel/lib.rs | 14 ++++++++++---- rust/kernel/net/phy.rs | 2 +- rust/kernel/sync/lock/global.rs | 6 ++++-- rust/macros/lib.rs | 6 ++++-- rust/macros/module.rs | 7 +++++-- samples/rust/rust_minimal.rs | 2 +- samples/rust/rust_print_main.rs | 2 +- 8 files changed, 27 insertions(+), 14 deletions(-) diff --git a/drivers/block/rnull.rs b/drivers/block/rnull.rs index 5de7223beb4d..0e0e9ed7851e 100644 --- a/drivers/block/rnull.rs +++ b/drivers/block/rnull.rs @@ -36,7 +36,7 @@ struct NullBlkModule { } impl kernel::Module for NullBlkModule { - fn init(_module: &'static ThisModule) -> Result { + fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result { pr_info!("Rust null_blk loaded\n"); let tagset = Arc::pin_init(TagSet::new(1, 256, 1), flags::GFP_KERNEL)?; diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index e1065a7551a3..686db6aa3323 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -90,7 +90,7 @@ pub trait Module: Sized + Sync + Send { /// should do. /// /// Equivalent to the `module_init` macro in the C API. - fn init(module: &'static ThisModule) -> error::Result; + fn init(name: &'static str::CStr, module: &'static ThisModule) -> error::Result; } /// A module that is pinned and initialised in-place. @@ -98,13 +98,19 @@ pub trait InPlaceModule: Sync + Send { /// Creates an initialiser for the module. /// /// It is called when the module is loaded. - fn init(module: &'static ThisModule) -> impl init::PinInit; + fn init( + name: &'static str::CStr, + module: &'static ThisModule, + ) -> impl init::PinInit; } impl InPlaceModule for T { - fn init(module: &'static ThisModule) -> impl init::PinInit { + fn init( + name: &'static str::CStr, + module: &'static ThisModule, + ) -> impl init::PinInit { let initer = move |slot: *mut Self| { - let m = ::init(module)?; + let m = ::init(name, module)?; // SAFETY: `slot` is valid for write per the contract with `pin_init_from_closure`. unsafe { slot.write(m) }; diff --git a/rust/kernel/net/phy.rs b/rust/kernel/net/phy.rs index b89c681d97c0..0f41df2e6b96 100644 --- a/rust/kernel/net/phy.rs +++ b/rust/kernel/net/phy.rs @@ -903,7 +903,7 @@ struct Module { [$($crate::net::phy::create_phy_driver::<$driver>()),+]; impl $crate::Module for Module { - fn init(module: &'static ThisModule) -> Result { + fn init(_name: &'static CStr, module: &'static ThisModule) -> Result { // SAFETY: The anonymous constant guarantees that nobody else can access // the `DRIVERS` static. The array is used only in the C side. let drivers = unsafe { &mut DRIVERS }; diff --git a/rust/kernel/sync/lock/global.rs b/rust/kernel/sync/lock/global.rs index 480ee724e3cc..feff4638e20b 100644 --- a/rust/kernel/sync/lock/global.rs +++ b/rust/kernel/sync/lock/global.rs @@ -187,6 +187,7 @@ pub fn get_mut(&mut self) -> &mut T { /// ``` /// # mod ex { /// # use kernel::prelude::*; +/// # use kernel::str; /// kernel::sync::global_lock! { /// // SAFETY: Initialized in module initializer before first use. /// unsafe(uninit) static MY_COUNTER: Mutex = 0; @@ -199,7 +200,7 @@ pub fn get_mut(&mut self) -> &mut T { /// } /// /// impl kernel::Module for MyModule { -/// fn init(_module: &'static ThisModule) -> Result { +/// fn init(_name: &'static str::CStr, _module: &'static ThisModule) -> Result { /// // SAFETY: Called exactly once. /// unsafe { MY_COUNTER.init() }; /// @@ -216,6 +217,7 @@ pub fn get_mut(&mut self) -> &mut T { /// # mod ex { /// # use kernel::prelude::*; /// use kernel::sync::{GlobalGuard, GlobalLockedBy}; +/// # use kernel::str; /// /// kernel::sync::global_lock! { /// // SAFETY: Initialized in module initializer before first use. @@ -239,7 +241,7 @@ pub fn get_mut(&mut self) -> &mut T { /// } /// /// impl kernel::Module for MyModule { -/// fn init(_module: &'static ThisModule) -> Result { +/// fn init(_name: &'static str::CStr, _module: &'static ThisModule) -> Result { /// // SAFETY: Called exactly once. /// unsafe { MY_MUTEX.init() }; /// diff --git a/rust/macros/lib.rs b/rust/macros/lib.rs index 4ab94e44adfe..d669f9cd1726 100644 --- a/rust/macros/lib.rs +++ b/rust/macros/lib.rs @@ -32,6 +32,7 @@ /// /// ``` /// use kernel::prelude::*; +/// use kernel::str; /// /// module!{ /// type: MyModule, @@ -45,7 +46,7 @@ /// struct MyModule(i32); /// /// impl kernel::Module for MyModule { -/// fn init(_module: &'static ThisModule) -> Result { +/// fn init(_name: &'static str::CStr, _module: &'static ThisModule) -> Result { /// let foo: i32 = 42; /// pr_info!("I contain: {}\n", foo); /// Ok(Self(foo)) @@ -65,6 +66,7 @@ /// /// ``` /// use kernel::prelude::*; +/// use kernel::str; /// /// module!{ /// type: MyDeviceDriverModule, @@ -78,7 +80,7 @@ /// struct MyDeviceDriverModule; /// /// impl kernel::Module for MyDeviceDriverModule { -/// fn init(_module: &'static ThisModule) -> Result { +/// fn init(_name: &'static str::CStr, _module: &'static ThisModule) -> Result { /// Ok(Self) /// } /// } diff --git a/rust/macros/module.rs b/rust/macros/module.rs index 2587f41b0d39..1f14ef55341a 100644 --- a/rust/macros/module.rs +++ b/rust/macros/module.rs @@ -333,8 +333,11 @@ mod __module_init {{ /// /// This function must only be called once. unsafe fn __init() -> kernel::ffi::c_int {{ - let initer = - <{type_} as kernel::InPlaceModule>::init(&super::super::THIS_MODULE); + let initer = <{type_} as kernel::InPlaceModule>::init( + kernel::c_str!(\"{name}\"), + &super::super::THIS_MODULE + ); + // SAFETY: No data race, since `__MOD` can only be accessed by this module // and there only `__init` and `__exit` access it. These functions are only // called once and `__exit` cannot be called before or during `__init`. diff --git a/samples/rust/rust_minimal.rs b/samples/rust/rust_minimal.rs index 4aaf117bf8e3..1577dc34e563 100644 --- a/samples/rust/rust_minimal.rs +++ b/samples/rust/rust_minimal.rs @@ -17,7 +17,7 @@ struct RustMinimal { } impl kernel::Module for RustMinimal { - fn init(_module: &'static ThisModule) -> Result { + fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result { pr_info!("Rust minimal sample (init)\n"); pr_info!("Am I built-in? {}\n", !cfg!(MODULE)); diff --git a/samples/rust/rust_print_main.rs b/samples/rust/rust_print_main.rs index aed90a6feecf..0853d767439b 100644 --- a/samples/rust/rust_print_main.rs +++ b/samples/rust/rust_print_main.rs @@ -41,7 +41,7 @@ fn arc_print() -> Result { } impl kernel::Module for RustPrint { - fn init(_module: &'static ThisModule) -> Result { + fn init(_name: &'static CStr, _module: &'static ThisModule) -> Result { pr_info!("Rust printing macros sample (init)\n"); pr_emerg!("Emergency message (level 0) without args\n"); From patchwork Thu Dec 5 14:14:33 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895427 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 274A217579; Thu, 5 Dec 2024 14:15:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408160; cv=none; b=ZLpx2KOTYxXEiEBVjBhXjMYtaQta+GtvYZspGBtm1R/6IVrYLHPx1jZX6mVO7sF6VxjJTWBaG2X60mNOPL8DrcZl5T4caxB9GpWl0GyNmQ0cWyeOwHaPGaNvRJ1yK0ar2+H1kXexdaQGCNugnNtoJq1oPHOr/EHcLMIeqtza5/c= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408160; c=relaxed/simple; bh=UY79Fyz+WjTgpTgNuQWqioy0XVY37/7qviisSR+YttE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TJG0wbC/s7mDFKA5ITseFHuqeAsESP/6zC/KH0nv/txl9OZwfymtHSZA5olOnNIo0ySbnBkYdYegsiqUpRl0T16mbOpZWCvqZT4jRGzjo0bZ3f4rY7TgOX3yWte1c1xQRl0Il5E7ISvxnD0h3+WJ7c/abitbfb9NQo4Vp9Mbovw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fhcZvTYq; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fhcZvTYq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2F1FC4CED1; Thu, 5 Dec 2024 14:15:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408159; bh=UY79Fyz+WjTgpTgNuQWqioy0XVY37/7qviisSR+YttE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fhcZvTYqEca+xNdFEzSigpcAnNoP3ajZRvW77/Sr9wqeaoCSgLIxwSbfsTAEKWg/G An/XSWFBYIE6tvY2w7D2b10eJHuxV3eylOTcGbYe/MJuATc3y/Hb2Tv3NHEOja6hGF yar2KpMzLuLCYTksL/WqIbRH+mm0BGITmvP2Q32fqApNmwSxDEnolwCuw8GN6hJFF2 kct1w11zfglJ4yPpDQ2cX9KqJKtniFCpUtvA0ezUyfEu4q+OM5yXcwvbuIt4IbtfWp YaTToiTIb6XqKUBB/g4//3hVZIYBf4TTzhFyMAkwuyhFcaAPM1JX8tQKG4R+6H8R22 /YdXAfJNvNBVg== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich , Wedson Almeida Filho Subject: [PATCH v4 02/13] rust: implement generic driver registration Date: Thu, 5 Dec 2024 15:14:33 +0100 Message-ID: <20241205141533.111830-3-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement the generic `Registration` type and the `DriverOps` trait. The `Registration` structure is the common type that represents a driver registration and is typically bound to the lifetime of a module. However, it doesn't implement actual calls to the kernel's driver core to register drivers itself. Instead the `DriverOps` trait is provided to subsystems, which have to implement `DriverOps::register` and `DrvierOps::unregister`. Subsystems have to provide an implementation for both of those methods where the subsystem specific variants to register / unregister a driver have to implemented. For instance, the PCI subsystem would call __pci_register_driver() from `DriverOps::register` and pci_unregister_driver() from `DrvierOps::unregister`. Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + rust/kernel/driver.rs | 120 ++++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 3 files changed, 122 insertions(+) create mode 100644 rust/kernel/driver.rs diff --git a/MAINTAINERS b/MAINTAINERS index 1e930c7a58b1..085b20dc5c0b 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7031,6 +7031,7 @@ F: include/linux/kobj* F: include/linux/property.h F: lib/kobj* F: rust/kernel/device.rs +F: rust/kernel/driver.rs DRIVERS FOR OMAP ADAPTIVE VOLTAGE SCALING (AVS) M: Nishanth Menon diff --git a/rust/kernel/driver.rs b/rust/kernel/driver.rs new file mode 100644 index 000000000000..3ec0ba0556a1 --- /dev/null +++ b/rust/kernel/driver.rs @@ -0,0 +1,120 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generic support for drivers of different buses (e.g., PCI, Platform, Amba, etc.). +//! +//! Each bus / subsystem is expected to implement [`RegistrationOps`], which allows drivers to +//! register using the [`Registration`] class. + +use crate::error::{Error, Result}; +use crate::{init::PinInit, str::CStr, try_pin_init, types::Opaque, ThisModule}; +use core::pin::Pin; +use macros::{pin_data, pinned_drop}; + +/// The [`RegistrationOps`] trait serves as generic interface for subsystems (e.g., PCI, Platform, +/// Amba, etc.) to provide the corresponding subsystem specific implementation to register / +/// unregister a driver of the particular type (`RegType`). +/// +/// For instance, the PCI subsystem would set `RegType` to `bindings::pci_driver` and call +/// `bindings::__pci_register_driver` from `RegistrationOps::register` and +/// `bindings::pci_unregister_driver` from `RegistrationOps::unregister`. +pub trait RegistrationOps { + /// The type that holds information about the registration. This is typically a struct defined + /// by the C portion of the kernel. + type RegType: Default; + + /// Registers a driver. + /// + /// On success, `reg` must remain pinned and valid until the matching call to + /// [`RegistrationOps::unregister`]. + fn register( + reg: &mut Self::RegType, + name: &'static CStr, + module: &'static ThisModule, + ) -> Result; + + /// Unregisters a driver previously registered with [`RegistrationOps::register`]. + fn unregister(reg: &mut Self::RegType); +} + +/// A [`Registration`] is a generic type that represents the registration of some driver type (e.g. +/// `bindings::pci_driver`). Therefore a [`Registration`] must be initialized with a type that +/// implements the [`RegistrationOps`] trait, such that the generic `T::register` and +/// `T::unregister` calls result in the subsystem specific registration calls. +/// +///Once the `Registration` structure is dropped, the driver is unregistered. +#[pin_data(PinnedDrop)] +pub struct Registration { + #[pin] + reg: Opaque, +} + +// SAFETY: `Registration` has no fields or methods accessible via `&Registration`, so it is safe to +// share references to it with multiple threads as nothing can be done. +unsafe impl Sync for Registration {} + +// SAFETY: Both registration and unregistration are implemented in C and safe to be performed from +// any thread, so `Registration` is `Send`. +unsafe impl Send for Registration {} + +impl Registration { + /// Creates a new instance of the registration object. + pub fn new(name: &'static CStr, module: &'static ThisModule) -> impl PinInit { + try_pin_init!(Self { + reg <- Opaque::try_ffi_init(|ptr: *mut T::RegType| { + // SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write. + unsafe { ptr.write(T::RegType::default()) }; + + // SAFETY: `try_ffi_init` guarantees that `ptr` is valid for write, and it has + // just been initialised above, so it's also valid for read. + let drv = unsafe { &mut *ptr }; + + T::register(drv, name, module) + }), + }) + } +} + +#[pinned_drop] +impl PinnedDrop for Registration { + fn drop(self: Pin<&mut Self>) { + // SAFETY: The existence of the `Registration` guarantees that `self.reg.get()` is properly + // aligned and points to a valid value. + let drv = unsafe { &mut *self.reg.get() }; + + T::unregister(drv); + } +} + +/// A kernel module that only registers the given driver on init. +/// +/// This is a helper struct to make it easier to define single-functionality modules, in this case, +/// modules that offer a single driver. +#[pin_data] +pub struct Module { + #[pin] + _driver: Registration, +} + +impl crate::InPlaceModule for Module { + fn init(name: &'static CStr, module: &'static ThisModule) -> impl PinInit { + try_pin_init!(Self { + _driver <- Registration::::new(name, module), + }) + } +} + +/// Declares a kernel module that exposes a single driver. +/// +/// It is meant to be used as a helper by other subsystems so they can more easily expose their own +/// macros. +#[macro_export] +macro_rules! module_driver { + (<$gen_type:ident>, $driver_ops:ty, { type: $type:ty, $($f:tt)* }) => { + type Ops<$gen_type> = $driver_ops; + type ModuleType = $crate::driver::Module>; + $crate::prelude::module! { + type: ModuleType, + $($f)* + } + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 686db6aa3323..0a719396256f 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -35,6 +35,7 @@ mod build_assert; pub mod cred; pub mod device; +pub mod driver; pub mod error; #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] pub mod firmware; From patchwork Thu Dec 5 14:14:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895428 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7311417579; Thu, 5 Dec 2024 14:16:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408166; cv=none; b=aNJqtr2H5jGJIRQoq7BC3F+Eb9k1CBVIWnDSe+epv53XqULsywDCGDXQEnsqRqNcfQSKF+HBn3Lolpgh0xOZbHT2yUiG+Da6QfxkJdoRQue9W6iHgvXnhEGwT+lzJLIkiflRhwKEg+PhSrAIWLxi7qm2Hz/pSxOdbvOrdRDXR7Y= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408166; c=relaxed/simple; bh=6EMLTiB3r1DAHJtnFlYpl6BfUpoo/tvp3QNluzHEEOw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E+GU55m2vQ59UcNgfma9YDa0fvQ4w5VcRUa26SWb49HhOiNq3SoBp7tAWwm0XgFByMCDyDnnLlygMhpcBWeJ13XcIkNI+9MJtD4qIe9IUgTmzp20dlknMFJWGwdq5iniSMEJHR4YmJCIvPE8Q4gLWr3O+bL6UF6E9XLgFz3ThVs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=b2L5cr7B; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="b2L5cr7B" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1D76FC4CEE0; Thu, 5 Dec 2024 14:15:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408166; bh=6EMLTiB3r1DAHJtnFlYpl6BfUpoo/tvp3QNluzHEEOw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b2L5cr7Bghrf3FAS1OHpQlDF/WiO1xi6n96HT945Va+sTTYkK66gu2gZXAxSKeJdm +2HZiuf5gz6kLz5Yp9vtva6x19R+3qFx2q+1mo3ikadzz6S+WmJ++S4XM7ljEuAG0f gQly9c2sItSbDNLjhVPr+0l7H+TybX6IbwxKc0dlFn0xfSbf/LtdF41GfQ+Ru7j2Np kvNh9X/sXH1xRAcMGLV2mbqjdTP0NHJGPxVUcducEbPjpj0TDpu/rVMnEXueXsIh6R 9/a/GdLVcZCoar6DCaKd0xQh8V7EzJGKbq+RRyG2RW/ntlVUyaPYerQJJ1VB2pc33o h4KP6B4k0jLuA== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich , Wedson Almeida Filho Subject: [PATCH v4 03/13] rust: implement `IdArray`, `IdTable` and `RawDeviceId` Date: Thu, 5 Dec 2024 15:14:34 +0100 Message-ID: <20241205141533.111830-4-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Most subsystems use some kind of ID to match devices and drivers. Hence, we have to provide Rust drivers an abstraction to register an ID table for the driver to match. Generally, those IDs are subsystem specific and hence need to be implemented by the corresponding subsystem. However, the `IdArray`, `IdTable` and `RawDeviceId` types provide a generalized implementation that makes the life of subsystems easier to do so. Co-developed-by: Wedson Almeida Filho Signed-off-by: Wedson Almeida Filho Co-developed-by: Gary Guo Signed-off-by: Gary Guo Co-developed-by: Fabien Parent Signed-off-by: Fabien Parent Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + rust/kernel/device_id.rs | 166 +++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 6 ++ 3 files changed, 173 insertions(+) create mode 100644 rust/kernel/device_id.rs diff --git a/MAINTAINERS b/MAINTAINERS index 085b20dc5c0b..6f952d5508e9 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7031,6 +7031,7 @@ F: include/linux/kobj* F: include/linux/property.h F: lib/kobj* F: rust/kernel/device.rs +F: rust/kernel/device_id.rs F: rust/kernel/driver.rs DRIVERS FOR OMAP ADAPTIVE VOLTAGE SCALING (AVS) diff --git a/rust/kernel/device_id.rs b/rust/kernel/device_id.rs new file mode 100644 index 000000000000..8ba227dc3d3a --- /dev/null +++ b/rust/kernel/device_id.rs @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generic implementation of device IDs. +//! +//! Each bus / subsystem that matches device and driver through a bus / subsystem specific ID is +//! expected to implement [`RawDeviceId`]. + +use core::mem::MaybeUninit; + +/// Marker trait to indicate a Rust device ID type represents a corresponding C device ID type. +/// +/// This is meant to be implemented by buses/subsystems so that they can use [`IdTable`] to +/// guarantee (at compile-time) zero-termination of device id tables provided by drivers. +/// +/// # Safety +/// +/// Implementers must ensure that: +/// - `Self` is layout-compatible with [`RawDeviceId::RawType`]; i.e. it's safe to transmute to +/// `RawDeviceId`. +/// +/// This requirement is needed so `IdArray::new` can convert `Self` to `RawType` when building +/// the ID table. +/// +/// Ideally, this should be achieved using a const function that does conversion instead of +/// transmute; however, const trait functions relies on `const_trait_impl` unstable feature, +/// which is broken/gone in Rust 1.73. +/// +/// - `DRIVER_DATA_OFFSET` is the offset of context/data field of the device ID (usually named +/// `driver_data`) of the device ID, the field is suitable sized to write a `usize` value. +/// +/// Similar to the previous requirement, the data should ideally be added during `Self` to +/// `RawType` conversion, but there's currently no way to do it when using traits in const. +pub unsafe trait RawDeviceId { + /// The raw type that holds the device id. + /// + /// Id tables created from [`Self`] are going to hold this type in its zero-terminated array. + type RawType: Copy; + + /// The offset to the context/data field. + const DRIVER_DATA_OFFSET: usize; + + /// The index stored at `DRIVER_DATA_OFFSET` of the implementor of the [`RawDeviceId`] trait. + fn index(&self) -> usize; +} + +/// A zero-terminated device id array. +#[repr(C)] +pub struct RawIdArray { + ids: [T::RawType; N], + sentinel: MaybeUninit, +} + +impl RawIdArray { + #[doc(hidden)] + pub const fn size(&self) -> usize { + core::mem::size_of::() + } +} + +/// A zero-terminated device id array, followed by context data. +#[repr(C)] +pub struct IdArray { + raw_ids: RawIdArray, + id_infos: [U; N], +} + +impl IdArray { + /// Creates a new instance of the array. + /// + /// The contents are derived from the given identifiers and context information. + pub const fn new(ids: [(T, U); N]) -> Self { + let mut raw_ids = [const { MaybeUninit::::uninit() }; N]; + let mut infos = [const { MaybeUninit::uninit() }; N]; + + let mut i = 0usize; + while i < N { + // SAFETY: by the safety requirement of `RawDeviceId`, we're guaranteed that `T` is + // layout-wise compatible with `RawType`. + raw_ids[i] = unsafe { core::mem::transmute_copy(&ids[i].0) }; + // SAFETY: by the safety requirement of `RawDeviceId`, this would be effectively + // `raw_ids[i].driver_data = i;`. + unsafe { + raw_ids[i] + .as_mut_ptr() + .byte_offset(T::DRIVER_DATA_OFFSET as _) + .cast::() + .write(i); + } + + // SAFETY: this is effectively a move: `infos[i] = ids[i].1`. We make a copy here but + // later forget `ids`. + infos[i] = MaybeUninit::new(unsafe { core::ptr::read(&ids[i].1) }); + i += 1; + } + + core::mem::forget(ids); + + Self { + raw_ids: RawIdArray { + // SAFETY: this is effectively `array_assume_init`, which is unstable, so we use + // `transmute_copy` instead. We have initialized all elements of `raw_ids` so this + // `array_assume_init` is safe. + ids: unsafe { core::mem::transmute_copy(&raw_ids) }, + sentinel: MaybeUninit::zeroed(), + }, + // SAFETY: We have initialized all elements of `infos` so this `array_assume_init` is + // safe. + id_infos: unsafe { core::mem::transmute_copy(&infos) }, + } + } + + /// Reference to the contained [`RawIdArray`]. + pub const fn raw_ids(&self) -> &RawIdArray { + &self.raw_ids + } +} + +/// A device id table. +/// +/// This trait is only implemented by `IdArray`. +/// +/// The purpose of this trait is to allow `&'static dyn IdArray` to be in context when `N` in +/// `IdArray` doesn't matter. +pub trait IdTable { + /// Obtain the pointer to the ID table. + fn as_ptr(&self) -> *const T::RawType; + + /// Obtain the pointer to the bus specific device ID from an index. + fn id(&self, index: usize) -> &T::RawType; + + /// Obtain the pointer to the driver-specific information from an index. + fn info(&self, index: usize) -> &U; +} + +impl IdTable for IdArray { + fn as_ptr(&self) -> *const T::RawType { + // This cannot be `self.ids.as_ptr()`, as the return pointer must have correct provenance + // to access the sentinel. + (self as *const Self).cast() + } + + fn id(&self, index: usize) -> &T::RawType { + &self.raw_ids.ids[index] + } + + fn info(&self, index: usize) -> &U { + &self.id_infos[index] + } +} + +/// Create device table alias for modpost. +#[macro_export] +macro_rules! module_device_table { + ($table_type: literal, $module_table_name:ident, $table_name:ident) => { + #[rustfmt::skip] + #[export_name = + concat!("__mod_", $table_type, + "__", module_path!(), + "_", line!(), + "_", stringify!($table_name), + "_device_table") + ] + static $module_table_name: [core::mem::MaybeUninit; $table_name.raw_ids().size()] = + unsafe { core::mem::transmute_copy($table_name.raw_ids()) }; + }; +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 0a719396256f..b5da7c520eb8 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -18,6 +18,11 @@ #![feature(inline_const)] #![feature(lint_reasons)] #![feature(unsize)] +// Stable in Rust 1.83 +#![feature(const_maybe_uninit_as_mut_ptr)] +#![feature(const_mut_refs)] +#![feature(const_ptr_write)] +#![feature(const_refs_to_cell)] // Ensure conditional compilation based on the kernel configuration works; // otherwise we may silently break things like initcall handling. @@ -35,6 +40,7 @@ mod build_assert; pub mod cred; pub mod device; +pub mod device_id; pub mod driver; pub mod error; #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] From patchwork Thu Dec 5 14:14:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895429 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C815121C161; Thu, 5 Dec 2024 14:16:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408172; cv=none; b=tVtVRm4p8NpnzygvOQD3CyYV8ManG3D9XXkZybodAq2mRhQoXf+ikSxTlYU/sG1h1L/GWHncowyMIk+cXDCyvADkqr+QnzARpDejHUqoH+60H2KayD0hr55YgsTpUS73pnKt4NV+ycGEKEYvy3uWEqiL2Mpq4y509NAhi2/3Qfw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408172; c=relaxed/simple; bh=e8fdtrnJQD4e+C55I6bdwSGwqVTXC5F9OkgGcKeaTSw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kRLVu/G6DoLpoEEJPAHoWV2pH4MHXYK5zaXyYCJkTbTMg7TskSXoJcg0ur97EfMiFl8eNcyIuhfol0EiF1EtaP+KyOVplG4iXqLzIZ5VvcjudSaqfcrMwsik3Gq7FIHvxeOAdxWgi3N8eGoAn5kSsdhm90UhRUESDiTRKu+sZr8= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=LZOUuyqZ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="LZOUuyqZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CBF6C4CEDC; Thu, 5 Dec 2024 14:16:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408172; bh=e8fdtrnJQD4e+C55I6bdwSGwqVTXC5F9OkgGcKeaTSw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=LZOUuyqZzEYn2PZBkuoP9J8LjVgEYGJ/feeMokj9OlgPeH1W8YYF1Ddh80CYAZGUK eaJu9y9d3CDtrS+9zqdc4Tnhg+ehVbKMqLPC2BDOJZMlatq9Y6vP22jdQfM4PwD4Zw CaguFa5xbYjx9VrJZFZMNoGbda3Qb7N7uPTuCdnRugXZJPH+6QAqIKfVpeciIFM6mC cMt/8RsoZcnnZt+7My3pzGC/aQVHNNITo3QN+ukrAQ/XR+Z3GaWNjo5ikyjMe4D2bg ikbu8WD2wH1W4fMfpmn3v5wcS4C7UhwCBT8Xx4s40g1/przyNu+4F9xiZFT1ZC/Yfk p8gnIStD2xNLg== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Wedson Almeida Filho , Danilo Krummrich Subject: [PATCH v4 04/13] rust: add rcu abstraction Date: Thu, 5 Dec 2024 15:14:35 +0100 Message-ID: <20241205141533.111830-5-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Wedson Almeida Filho Add a simple abstraction to guard critical code sections with an rcu read lock. Signed-off-by: Wedson Almeida Filho Co-developed-by: Danilo Krummrich Signed-off-by: Danilo Krummrich --- rust/helpers/helpers.c | 1 + rust/helpers/rcu.c | 13 ++++++++++++ rust/kernel/sync.rs | 1 + rust/kernel/sync/rcu.rs | 47 +++++++++++++++++++++++++++++++++++++++++ 4 files changed, 62 insertions(+) create mode 100644 rust/helpers/rcu.c create mode 100644 rust/kernel/sync/rcu.rs diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index dcf827a61b52..060750af6524 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -20,6 +20,7 @@ #include "page.c" #include "pid_namespace.c" #include "rbtree.c" +#include "rcu.c" #include "refcount.c" #include "security.c" #include "signal.c" diff --git a/rust/helpers/rcu.c b/rust/helpers/rcu.c new file mode 100644 index 000000000000..f1cec6583513 --- /dev/null +++ b/rust/helpers/rcu.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void rust_helper_rcu_read_lock(void) +{ + rcu_read_lock(); +} + +void rust_helper_rcu_read_unlock(void) +{ + rcu_read_unlock(); +} diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index 1eab7ebf25fd..0654008198b2 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -12,6 +12,7 @@ pub mod lock; mod locked_by; pub mod poll; +pub mod rcu; pub use arc::{Arc, ArcBorrow, UniqueArc}; pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult}; diff --git a/rust/kernel/sync/rcu.rs b/rust/kernel/sync/rcu.rs new file mode 100644 index 000000000000..3beef70d5f34 --- /dev/null +++ b/rust/kernel/sync/rcu.rs @@ -0,0 +1,47 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! RCU support. +//! +//! C header: [`include/linux/rcupdate.h`](srctree/include/linux/rcupdate.h) + +use crate::{bindings, types::NotThreadSafe}; + +/// Evidence that the RCU read side lock is held on the current thread/CPU. +/// +/// The type is explicitly not `Send` because this property is per-thread/CPU. +/// +/// # Invariants +/// +/// The RCU read side lock is actually held while instances of this guard exist. +pub struct Guard(NotThreadSafe); + +impl Guard { + /// Acquires the RCU read side lock and returns a guard. + pub fn new() -> Self { + // SAFETY: An FFI call with no additional requirements. + unsafe { bindings::rcu_read_lock() }; + // INVARIANT: The RCU read side lock was just acquired above. + Self(NotThreadSafe) + } + + /// Explicitly releases the RCU read side lock. + pub fn unlock(self) {} +} + +impl Default for Guard { + fn default() -> Self { + Self::new() + } +} + +impl Drop for Guard { + fn drop(&mut self) { + // SAFETY: By the type invariants, the rcu read side is locked, so it is ok to unlock it. + unsafe { bindings::rcu_read_unlock() }; + } +} + +/// Acquires the RCU read side lock. +pub fn read_lock() -> Guard { + Guard::new() +} From patchwork Thu Dec 5 14:14:36 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895430 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C93F17579; Thu, 5 Dec 2024 14:16:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408180; cv=none; b=jpqY1fTO5UIEQfe/Q8TX4PNrqAFZ7Riz0r4x9shFl75CE2aBsyJ4UV5udkRTJ5i3wVpKXTeRlVUwhqH4pZOEkRAyNRyw0lzyyine6m9ihE9BBfkWJW0woNyD4Zyx9ntriWZouXSzw2rL7XMJ6EapJeA8CQKMgfIR5wiv5Mfwyuk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408180; c=relaxed/simple; bh=b+B4IKAkpmrCPvfD37chV6RamAFj9xhafB8kgzuaFqg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=V8HDN2Y9rjXEzj7fVk3VPiTNnyaolyQro2nbk5lxyl7vo63h/wC7TBbxcwRKhGdDgcwZSvrhU4RnngMu9sPQd/XjBlx4/dsW38ObFqR0hmlnQSEPwpRDycEIwALPVEALI/nwrG2FMazZM+ZEsKtsgA5J/epfWZ7cbSHAgdk+CxE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Cvy9hidS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Cvy9hidS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DA93EC4CED1; Thu, 5 Dec 2024 14:16:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408178; bh=b+B4IKAkpmrCPvfD37chV6RamAFj9xhafB8kgzuaFqg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cvy9hidSin/7UM7CwgLqIjaZtBeJJllkaJrXWWDJCFMP6Uy923ObMD1UrspQFfK/f ySLp48WEmvQNaiwjeSqP7w3etkPWqpYOHXAvqLpJ3KbK8yoFTM5Kl8pXYqb8f6fDtO XpP7Zv4KZJNMOulwUc7Lp2weB1QR/r50TjFg6cyGTGqhfMI3Is3aVkmoEQr9vwx9Ss YEva1PzgR1iEBqmnumkDhPyrpDwBIF9jkwPDxoL1fBKlKSTdVen33cxu0FWQKPQazx 77JA7kFRunXdFQVNK1mG4r14JnmLQkmMEFSEt7mS2IileV8AVZwqYe+Y7qntn465KD rhoj5E3NJtC1w== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Wedson Almeida Filho , Danilo Krummrich Subject: [PATCH v4 05/13] rust: add `Revocable` type Date: Thu, 5 Dec 2024 15:14:36 +0100 Message-ID: <20241205141533.111830-6-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 From: Wedson Almeida Filho Revocable allows access to objects to be safely revoked at run time. This is useful, for example, for resources allocated during device probe; when the device is removed, the driver should stop accessing the device resources even if another state is kept in memory due to existing references (i.e., device context data is ref-counted and has a non-zero refcount after removal of the device). Signed-off-by: Wedson Almeida Filho Co-developed-by: Danilo Krummrich Signed-off-by: Danilo Krummrich --- rust/kernel/lib.rs | 1 + rust/kernel/revocable.rs | 235 +++++++++++++++++++++++++++++++++++++++ 2 files changed, 236 insertions(+) create mode 100644 rust/kernel/revocable.rs diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index b5da7c520eb8..200c5f99a805 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -60,6 +60,7 @@ pub mod prelude; pub mod print; pub mod rbtree; +pub mod revocable; pub mod security; pub mod seq_file; pub mod sizes; diff --git a/rust/kernel/revocable.rs b/rust/kernel/revocable.rs new file mode 100644 index 000000000000..fb675e58625a --- /dev/null +++ b/rust/kernel/revocable.rs @@ -0,0 +1,235 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Revocable objects. +//! +//! The [`Revocable`] type wraps other types and allows access to them to be revoked. The existence +//! of a [`RevocableGuard`] ensures that objects remain valid. + +use crate::{ + bindings, + init::{self}, + prelude::*, + sync::rcu, + types::Opaque, +}; +use core::{ + marker::PhantomData, + ops::Deref, + ptr::drop_in_place, + sync::atomic::{AtomicBool, Ordering}, +}; + +/// An object that can become inaccessible at runtime. +/// +/// Once access is revoked and all concurrent users complete (i.e., all existing instances of +/// [`RevocableGuard`] are dropped), the wrapped object is also dropped. +/// +/// # Examples +/// +/// ``` +/// # use kernel::revocable::Revocable; +/// +/// struct Example { +/// a: u32, +/// b: u32, +/// } +/// +/// fn add_two(v: &Revocable) -> Option { +/// let guard = v.try_access()?; +/// Some(guard.a + guard.b) +/// } +/// +/// let v = KBox::pin_init(Revocable::new(Example { a: 10, b: 20 }), GFP_KERNEL).unwrap(); +/// assert_eq!(add_two(&v), Some(30)); +/// v.revoke(); +/// assert_eq!(add_two(&v), None); +/// ``` +/// +/// Sample example as above, but explicitly using the rcu read side lock. +/// +/// ``` +/// # use kernel::revocable::Revocable; +/// use kernel::sync::rcu; +/// +/// struct Example { +/// a: u32, +/// b: u32, +/// } +/// +/// fn add_two(v: &Revocable) -> Option { +/// let guard = rcu::read_lock(); +/// let e = v.try_access_with_guard(&guard)?; +/// Some(e.a + e.b) +/// } +/// +/// let v = KBox::pin_init(Revocable::new(Example { a: 10, b: 20 }), GFP_KERNEL).unwrap(); +/// assert_eq!(add_two(&v), Some(30)); +/// v.revoke(); +/// assert_eq!(add_two(&v), None); +/// ``` +#[pin_data(PinnedDrop)] +pub struct Revocable { + is_available: AtomicBool, + #[pin] + data: Opaque, +} + +// SAFETY: `Revocable` is `Send` if the wrapped object is also `Send`. This is because while the +// functionality exposed by `Revocable` can be accessed from any thread/CPU, it is possible that +// this isn't supported by the wrapped object. +unsafe impl Send for Revocable {} + +// SAFETY: `Revocable` is `Sync` if the wrapped object is both `Send` and `Sync`. We require `Send` +// from the wrapped object as well because of `Revocable::revoke`, which can trigger the `Drop` +// implementation of the wrapped object from an arbitrary thread. +unsafe impl Sync for Revocable {} + +impl Revocable { + /// Creates a new revocable instance of the given data. + pub fn new(data: impl PinInit) -> impl PinInit { + pin_init!(Self { + is_available: AtomicBool::new(true), + // SAFETY: The closure only returns `Ok(())` if `ptr` is fully initialized; on error + // `ptr` is not partially initialized and does not need to be dropped. + data <- unsafe { + Opaque::try_ffi_init(|ptr: *mut T| { + init::PinInit::::__pinned_init(data, ptr) + }) + }, + }) + } + + /// Tries to access the revocable wrapped object. + /// + /// Returns `None` if the object has been revoked and is therefore no longer accessible. + /// + /// Returns a guard that gives access to the object otherwise; the object is guaranteed to + /// remain accessible while the guard is alive. In such cases, callers are not allowed to sleep + /// because another CPU may be waiting to complete the revocation of this object. + pub fn try_access(&self) -> Option> { + let guard = rcu::read_lock(); + if self.is_available.load(Ordering::Relaxed) { + // Since `self.is_available` is true, data is initialised and has to remain valid + // because the RCU read side lock prevents it from being dropped. + Some(RevocableGuard::new(self.data.get(), guard)) + } else { + None + } + } + + /// Tries to access the revocable wrapped object. + /// + /// Returns `None` if the object has been revoked and is therefore no longer accessible. + /// + /// Returns a shared reference to the object otherwise; the object is guaranteed to + /// remain accessible while the rcu read side guard is alive. In such cases, callers are not + /// allowed to sleep because another CPU may be waiting to complete the revocation of this + /// object. + pub fn try_access_with_guard<'a>(&'a self, _guard: &'a rcu::Guard) -> Option<&'a T> { + if self.is_available.load(Ordering::Relaxed) { + // SAFETY: Since `self.is_available` is true, data is initialised and has to remain + // valid because the RCU read side lock prevents it from being dropped. + Some(unsafe { &*self.data.get() }) + } else { + None + } + } + + /// # Safety + /// + /// Callers must ensure that there are no more concurrent users of the revocable object. + unsafe fn revoke_internal(&self, sync: bool) { + if self + .is_available + .compare_exchange(true, false, Ordering::Relaxed, Ordering::Relaxed) + .is_ok() + { + if sync { + // SAFETY: Just an FFI call, there are no further requirements. + unsafe { bindings::synchronize_rcu() }; + } + + // SAFETY: We know `self.data` is valid because only one CPU can succeed the + // `compare_exchange` above that takes `is_available` from `true` to `false`. + unsafe { drop_in_place(self.data.get()) }; + } + } + + /// Revokes access to and drops the wrapped object. + /// + /// Access to the object is revoked immediately to new callers of [`Revocable::try_access`], + /// expecting that there are no concurrent users of the object. + /// + /// # Safety + /// + /// Callers must ensure that there are no more concurrent users of the revocable object. + pub unsafe fn revoke_nosync(&self) { + // SAFETY: By the safety requirement of this function, the caller ensures that nobody is + // accessing the data anymore and hence we don't have to wait for the grace period to + // finish. + unsafe { self.revoke_internal(false) } + } + + /// Revokes access to and drops the wrapped object. + /// + /// Access to the object is revoked immediately to new callers of [`Revocable::try_access`]. + /// + /// If there are concurrent users of the object (i.e., ones that called + /// [`Revocable::try_access`] beforehand and still haven't dropped the returned guard), this + /// function waits for the concurrent access to complete before dropping the wrapped object. + pub fn revoke(&self) { + // SAFETY: By passing `true` we ask `revoke_internal` to wait for the grace period to + // finish. + unsafe { self.revoke_internal(true) } + } +} + +#[pinned_drop] +impl PinnedDrop for Revocable { + fn drop(self: Pin<&mut Self>) { + // Drop only if the data hasn't been revoked yet (in which case it has already been + // dropped). + // SAFETY: We are not moving out of `p`, only dropping in place + let p = unsafe { self.get_unchecked_mut() }; + if *p.is_available.get_mut() { + // SAFETY: We know `self.data` is valid because no other CPU has changed + // `is_available` to `false` yet, and no other CPU can do it anymore because this CPU + // holds the only reference (mutable) to `self` now. + unsafe { drop_in_place(p.data.get()) }; + } + } +} + +/// A guard that allows access to a revocable object and keeps it alive. +/// +/// CPUs may not sleep while holding on to [`RevocableGuard`] because it's in atomic context +/// holding the RCU read-side lock. +/// +/// # Invariants +/// +/// The RCU read-side lock is held while the guard is alive. +pub struct RevocableGuard<'a, T> { + data_ref: *const T, + _rcu_guard: rcu::Guard, + _p: PhantomData<&'a ()>, +} + +impl RevocableGuard<'_, T> { + fn new(data_ref: *const T, rcu_guard: rcu::Guard) -> Self { + Self { + data_ref, + _rcu_guard: rcu_guard, + _p: PhantomData, + } + } +} + +impl Deref for RevocableGuard<'_, T> { + type Target = T; + + fn deref(&self) -> &Self::Target { + // SAFETY: By the type invariants, we hold the rcu read-side lock, so the object is + // guaranteed to remain valid. + unsafe { &*self.data_ref } + } +} From patchwork Thu Dec 5 14:14:37 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895431 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 691F617579; Thu, 5 Dec 2024 14:16:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408185; cv=none; b=DhE3NR0CwWD8lJ1V4dOgnpC85OzAhdDD2B6/jPyph/gjv4wXMomXYy7We/Bm5LcEW/bvnrBNJ5WGfyz+W+OSIq/gNO+uin8Vc1AAPuDYv0ihiBYE+O8hcuEm6+tCcpMyntbWJ3LlTF++yFetJ1ZnkcDFvR3/z4F5dqqMvx+2PG0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408185; c=relaxed/simple; bh=6ec3IKuo5ZaJbO63hV5v3g852ycCrIy0fJPYsDCEvEc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QsSl5Tm+/Qiud6qrH+Iq6ZRFpF7xV2AvVEHQ3jOK9qu82m9qKZBnoeyiFPMwCuzBmrcuXaBqVWvvTf1ef8IEBnjqyW7EcuqxJzDQc//vgL/4sjFFWCsx7GCtL3YuG74TFjSusv6lvczL13g7jLiDtRTfqmXSjnA2pJI9FWH6EYk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c0zCJ79z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="c0zCJ79z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 440A0C4CEDC; Thu, 5 Dec 2024 14:16:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408185; bh=6ec3IKuo5ZaJbO63hV5v3g852ycCrIy0fJPYsDCEvEc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=c0zCJ79zqz6dTJuU0YOIeDh17tWOwDDYThpL5JsNeQJdoOFcoDaGGaFfT4CzPnQPB OgzyMdHUM5uAHHMjKtzGo7fKi+tZF5cbq05oxbTGuN7i/YdVHSffDfMK3/hbLy9get NNZMkxsMpvkBIcHcYEOXvGdSt8EWp/k5YOxtvJOluWgmwIqd0aAs3W/qt4Neu4esde KAbqmVl0zA398n5nXYWGWeFYdvQrJx72Ukq/JIIVjLJHl2cabcPe4FOZ/Yz1hcvd/K 1rdpxnS49C16eQHYgQhSFHWHxvu3pPjwSeaUfRlik2VY4MGCGV3z80roB7WGhGJEMy iax3YvXIqmV/Q== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 06/13] rust: add `io::{Io, IoRaw}` base types Date: Thu, 5 Dec 2024 15:14:37 +0100 Message-ID: <20241205141533.111830-7-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 I/O memory is typically either mapped through direct calls to ioremap() or subsystem / bus specific ones such as pci_iomap(). Even though subsystem / bus specific functions to map I/O memory are based on ioremap() / iounmap() it is not desirable to re-implement them in Rust. Instead, implement a base type for I/O mapped memory, which generically provides the corresponding accessors, such as `Io::readb` or `Io:try_readb`. `Io` supports an optional const generic, such that a driver can indicate the minimal expected and required size of the mapping at compile time. Correspondingly, calls to the 'non-try' accessors, support compile time checks of the I/O memory offset to read / write, while the 'try' accessors, provide boundary checks on runtime. `IoRaw` is meant to be embedded into a structure (e.g. pci::Bar or io::IoMem) which creates the actual I/O memory mapping and initializes `IoRaw` accordingly. To ensure that I/O mapped memory can't out-live the device it may be bound to, subsystems must embed the corresponding I/O memory type (e.g. pci::Bar) into a `Devres` container, such that it gets revoked once the device is unbound. Signed-off-by: Danilo Krummrich Reviewed-by: Alice Ryhl Tested-by: Daniel Almeida Reviewed-by: Daniel Almeida --- rust/helpers/helpers.c | 1 + rust/helpers/io.c | 101 ++++++++++++++++ rust/kernel/io.rs | 260 +++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 4 files changed, 363 insertions(+) create mode 100644 rust/helpers/io.c create mode 100644 rust/kernel/io.rs diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 060750af6524..63f9b1da179f 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -14,6 +14,7 @@ #include "cred.c" #include "err.c" #include "fs.c" +#include "io.c" #include "jump_label.c" #include "kunit.c" #include "mutex.c" diff --git a/rust/helpers/io.c b/rust/helpers/io.c new file mode 100644 index 000000000000..1dde6374c0e2 --- /dev/null +++ b/rust/helpers/io.c @@ -0,0 +1,101 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void __iomem *rust_helper_ioremap(phys_addr_t offset, size_t size) +{ + return ioremap(offset, size); +} + +void rust_helper_iounmap(volatile void __iomem *addr) +{ + return iounmap(addr); +} + +u8 rust_helper_readb(const volatile void __iomem *addr) +{ + return readb(addr); +} + +u16 rust_helper_readw(const volatile void __iomem *addr) +{ + return readw(addr); +} + +u32 rust_helper_readl(const volatile void __iomem *addr) +{ + return readl(addr); +} + +#ifdef CONFIG_64BIT +u64 rust_helper_readq(const volatile void __iomem *addr) +{ + return readq(addr); +} +#endif + +void rust_helper_writeb(u8 value, volatile void __iomem *addr) +{ + writeb(value, addr); +} + +void rust_helper_writew(u16 value, volatile void __iomem *addr) +{ + writew(value, addr); +} + +void rust_helper_writel(u32 value, volatile void __iomem *addr) +{ + writel(value, addr); +} + +#ifdef CONFIG_64BIT +void rust_helper_writeq(u64 value, volatile void __iomem *addr) +{ + writeq(value, addr); +} +#endif + +u8 rust_helper_readb_relaxed(const volatile void __iomem *addr) +{ + return readb_relaxed(addr); +} + +u16 rust_helper_readw_relaxed(const volatile void __iomem *addr) +{ + return readw_relaxed(addr); +} + +u32 rust_helper_readl_relaxed(const volatile void __iomem *addr) +{ + return readl_relaxed(addr); +} + +#ifdef CONFIG_64BIT +u64 rust_helper_readq_relaxed(const volatile void __iomem *addr) +{ + return readq_relaxed(addr); +} +#endif + +void rust_helper_writeb_relaxed(u8 value, volatile void __iomem *addr) +{ + writeb_relaxed(value, addr); +} + +void rust_helper_writew_relaxed(u16 value, volatile void __iomem *addr) +{ + writew_relaxed(value, addr); +} + +void rust_helper_writel_relaxed(u32 value, volatile void __iomem *addr) +{ + writel_relaxed(value, addr); +} + +#ifdef CONFIG_64BIT +void rust_helper_writeq_relaxed(u64 value, volatile void __iomem *addr) +{ + writeq_relaxed(value, addr); +} +#endif diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs new file mode 100644 index 000000000000..36aa2ec1bcc8 --- /dev/null +++ b/rust/kernel/io.rs @@ -0,0 +1,260 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Memory-mapped IO. +//! +//! C header: [`include/asm-generic/io.h`](srctree/include/asm-generic/io.h) + +use crate::error::{code::EINVAL, Result}; +use crate::{bindings, build_assert}; + +/// Raw representation of an MMIO region. +/// +/// By itself, the existence of an instance of this structure does not provide any guarantees that +/// the represented MMIO region does exist or is properly mapped. +/// +/// Instead, the bus specific MMIO implementation must convert this raw representation into an `Io` +/// instance providing the actual memory accessors. Only by the conversion into an `Io` structure +/// any guarantees are given. +pub struct IoRaw { + addr: usize, + maxsize: usize, +} + +impl IoRaw { + /// Returns a new `IoRaw` instance on success, an error otherwise. + pub fn new(addr: usize, maxsize: usize) -> Result { + if maxsize < SIZE { + return Err(EINVAL); + } + + Ok(Self { addr, maxsize }) + } + + /// Returns the base address of the MMIO region. + #[inline] + pub fn addr(&self) -> usize { + self.addr + } + + /// Returns the maximum size of the MMIO region. + #[inline] + pub fn maxsize(&self) -> usize { + self.maxsize + } +} + +/// IO-mapped memory, starting at the base address @addr and spanning @maxlen bytes. +/// +/// The creator (usually a subsystem / bus such as PCI) is responsible for creating the +/// mapping, performing an additional region request etc. +/// +/// # Invariant +/// +/// `addr` is the start and `maxsize` the length of valid I/O mapped memory region of size +/// `maxsize`. +/// +/// # Examples +/// +/// ```no_run +/// # use kernel::{bindings, io::{Io, IoRaw}}; +/// # use core::ops::Deref; +/// +/// // See also [`pci::Bar`] for a real example. +/// struct IoMem(IoRaw); +/// +/// impl IoMem { +/// /// # Safety +/// /// +/// /// [`paddr`, `paddr` + `SIZE`) must be a valid MMIO region that is mappable into the CPUs +/// /// virtual address space. +/// unsafe fn new(paddr: usize) -> Result{ +/// // SAFETY: By the safety requirements of this function [`paddr`, `paddr` + `SIZE`) is +/// // valid for `ioremap`. +/// let addr = unsafe { bindings::ioremap(paddr as _, SIZE.try_into().unwrap()) }; +/// if addr.is_null() { +/// return Err(ENOMEM); +/// } +/// +/// Ok(IoMem(IoRaw::new(addr as _, SIZE)?)) +/// } +/// } +/// +/// impl Drop for IoMem { +/// fn drop(&mut self) { +/// // SAFETY: `self.0.addr()` is guaranteed to be properly mapped by `Self::new`. +/// unsafe { bindings::iounmap(self.0.addr() as _); }; +/// } +/// } +/// +/// impl Deref for IoMem { +/// type Target = Io; +/// +/// fn deref(&self) -> &Self::Target { +/// // SAFETY: The memory range stored in `self` has been properly mapped in `Self::new`. +/// unsafe { Io::from_raw(&self.0) } +/// } +/// } +/// +///# fn no_run() -> Result<(), Error> { +/// // SAFETY: Invalid usage for example purposes. +/// let iomem = unsafe { IoMem::<{ core::mem::size_of::() }>::new(0xBAAAAAAD)? }; +/// iomem.writel(0x42, 0x0); +/// assert!(iomem.try_writel(0x42, 0x0).is_ok()); +/// assert!(iomem.try_writel(0x42, 0x4).is_err()); +/// # Ok(()) +/// # } +/// ``` +#[repr(transparent)] +pub struct Io(IoRaw); + +macro_rules! define_read { + ($(#[$attr:meta])* $name:ident, $try_name:ident, $type_name:ty) => { + /// Read IO data from a given offset known at compile time. + /// + /// Bound checks are performed on compile time, hence if the offset is not known at compile + /// time, the build will fail. + $(#[$attr])* + #[inline] + pub fn $name(&self, offset: usize) -> $type_name { + let addr = self.io_addr_assert::<$type_name>(offset); + + // SAFETY: By the type invariant `addr` is a valid address for MMIO operations. + unsafe { bindings::$name(addr as _) } + } + + /// Read IO data from a given offset. + /// + /// Bound checks are performed on runtime, it fails if the offset (plus the type size) is + /// out of bounds. + $(#[$attr])* + pub fn $try_name(&self, offset: usize) -> Result<$type_name> { + let addr = self.io_addr::<$type_name>(offset)?; + + // SAFETY: By the type invariant `addr` is a valid address for MMIO operations. + Ok(unsafe { bindings::$name(addr as _) }) + } + }; +} + +macro_rules! define_write { + ($(#[$attr:meta])* $name:ident, $try_name:ident, $type_name:ty) => { + /// Write IO data from a given offset known at compile time. + /// + /// Bound checks are performed on compile time, hence if the offset is not known at compile + /// time, the build will fail. + $(#[$attr])* + #[inline] + pub fn $name(&self, value: $type_name, offset: usize) { + let addr = self.io_addr_assert::<$type_name>(offset); + + // SAFETY: By the type invariant `addr` is a valid address for MMIO operations. + unsafe { bindings::$name(value, addr as _, ) } + } + + /// Write IO data from a given offset. + /// + /// Bound checks are performed on runtime, it fails if the offset (plus the type size) is + /// out of bounds. + $(#[$attr])* + pub fn $try_name(&self, value: $type_name, offset: usize) -> Result { + let addr = self.io_addr::<$type_name>(offset)?; + + // SAFETY: By the type invariant `addr` is a valid address for MMIO operations. + unsafe { bindings::$name(value, addr as _) } + Ok(()) + } + }; +} + +impl Io { + /// Converts an `IoRaw` into an `Io` instance, providing the accessors to the MMIO mapping. + /// + /// # Safety + /// + /// Callers must ensure that `addr` is the start of a valid I/O mapped memory region of size + /// `maxsize`. + pub unsafe fn from_raw<'a>(raw: &IoRaw) -> &'a Self { + // SAFETY: `Io` is a transparent wrapper around `IoRaw`. + unsafe { &*core::ptr::from_ref(raw).cast() } + } + + /// Returns the base address of this mapping. + #[inline] + pub fn addr(&self) -> usize { + self.0.addr() + } + + /// Returns the maximum size of this mapping. + #[inline] + pub fn maxsize(&self) -> usize { + self.0.maxsize() + } + + #[inline] + const fn offset_valid(offset: usize, size: usize) -> bool { + let type_size = core::mem::size_of::(); + if let Some(end) = offset.checked_add(type_size) { + end <= size && offset % type_size == 0 + } else { + false + } + } + + #[inline] + fn io_addr(&self, offset: usize) -> Result { + if !Self::offset_valid::(offset, self.maxsize()) { + return Err(EINVAL); + } + + // Probably no need to check, since the safety requirements of `Self::new` guarantee that + // this can't overflow. + self.addr().checked_add(offset).ok_or(EINVAL) + } + + #[inline] + fn io_addr_assert(&self, offset: usize) -> usize { + build_assert!(Self::offset_valid::(offset, SIZE)); + + self.addr() + offset + } + + define_read!(readb, try_readb, u8); + define_read!(readw, try_readw, u16); + define_read!(readl, try_readl, u32); + define_read!( + #[cfg(CONFIG_64BIT)] + readq, + try_readq, + u64 + ); + + define_read!(readb_relaxed, try_readb_relaxed, u8); + define_read!(readw_relaxed, try_readw_relaxed, u16); + define_read!(readl_relaxed, try_readl_relaxed, u32); + define_read!( + #[cfg(CONFIG_64BIT)] + readq_relaxed, + try_readq_relaxed, + u64 + ); + + define_write!(writeb, try_writeb, u8); + define_write!(writew, try_writew, u16); + define_write!(writel, try_writel, u32); + define_write!( + #[cfg(CONFIG_64BIT)] + writeq, + try_writeq, + u64 + ); + + define_write!(writeb_relaxed, try_writeb_relaxed, u8); + define_write!(writew_relaxed, try_writew_relaxed, u16); + define_write!(writel_relaxed, try_writel_relaxed, u32); + define_write!( + #[cfg(CONFIG_64BIT)] + writeq_relaxed, + try_writeq_relaxed, + u64 + ); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 200c5f99a805..d1f30b1a05fb 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -79,6 +79,7 @@ #[doc(hidden)] pub use bindings; +pub mod io; pub use macros; pub use uapi; From patchwork Thu Dec 5 14:14:38 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895432 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A32A421A443; Thu, 5 Dec 2024 14:16:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; 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Thu, 5 Dec 2024 14:16:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408191; bh=K2KyfvtuPiDOAe7kc1i3UaesmfSFJl49ORpVT8ygG3U=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NL1oyP/AbjrrkilkeKMRVXUZXyM6hAw9M93niOXx0jrIBsB/K5EFvst8UgfakX8MF 6C6P+zajZ1F7xchm7UMOfCqX+DCCkDFkLgoYKRe79by+/X0BbOH5kMnINH/ltSMJ5/ MbFBFLLzJxgGkiI4ErY2/fUKwPkkpBQ1HuGjMki0dFujssV6xMt4FK5EQ2YLaiGWoj J3LCxiHMe11KSXeAkMqhBkvdM5rCdgS5nJan19nVv2cDeeqfl/UeQN+i8hfjMi/UiI bhIHKbDrymxCDQHFANsVLXbCyOLyKVs71HwjMveeJ/zC224qfKUIjRQrUDriksCaKi bWZ0VNxbJGuLA== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 07/13] rust: add devres abstraction Date: Thu, 5 Dec 2024 15:14:38 +0100 Message-ID: <20241205141533.111830-8-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add a Rust abstraction for the kernel's devres (device resource management) implementation. The Devres type acts as a container to manage the lifetime and accessibility of device bound resources. Therefore it registers a devres callback and revokes access to the resource on invocation. Users of the Devres abstraction can simply free the corresponding resources in their Drop implementation, which is invoked when either the Devres instance goes out of scope or the devres callback leads to the resource being revoked, which implies a call to drop_in_place(). Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + rust/helpers/device.c | 10 +++ rust/helpers/helpers.c | 1 + rust/kernel/devres.rs | 179 +++++++++++++++++++++++++++++++++++++++++ rust/kernel/lib.rs | 1 + 5 files changed, 192 insertions(+) create mode 100644 rust/helpers/device.c create mode 100644 rust/kernel/devres.rs diff --git a/MAINTAINERS b/MAINTAINERS index 6f952d5508e9..a3535297ee6f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7032,6 +7032,7 @@ F: include/linux/property.h F: lib/kobj* F: rust/kernel/device.rs F: rust/kernel/device_id.rs +F: rust/kernel/devres.rs F: rust/kernel/driver.rs DRIVERS FOR OMAP ADAPTIVE VOLTAGE SCALING (AVS) diff --git a/rust/helpers/device.c b/rust/helpers/device.c new file mode 100644 index 000000000000..b2135c6686b0 --- /dev/null +++ b/rust/helpers/device.c @@ -0,0 +1,10 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +int rust_helper_devm_add_action(struct device *dev, + void (*action)(void *), + void *data) +{ + return devm_add_action(dev, action, data); +} diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 63f9b1da179f..a3b52aa021de 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -12,6 +12,7 @@ #include "build_assert.c" #include "build_bug.c" #include "cred.c" +#include "device.c" #include "err.c" #include "fs.c" #include "io.c" diff --git a/rust/kernel/devres.rs b/rust/kernel/devres.rs new file mode 100644 index 000000000000..57ddb49fde1d --- /dev/null +++ b/rust/kernel/devres.rs @@ -0,0 +1,179 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Devres abstraction +//! +//! [`Devres`] represents an abstraction for the kernel devres (device resource management) +//! implementation. + +use crate::{ + alloc::Flags, + bindings, + device::Device, + error::{Error, Result}, + prelude::*, + revocable::Revocable, + sync::Arc, +}; + +use core::ffi::c_void; +use core::ops::Deref; + +#[pin_data] +struct DevresInner { + #[pin] + data: Revocable, +} + +/// This abstraction is meant to be used by subsystems to containerize [`Device`] bound resources to +/// manage their lifetime. +/// +/// [`Device`] bound resources should be freed when either the resource goes out of scope or the +/// [`Device`] is unbound respectively, depending on what happens first. +/// +/// To achieve that [`Devres`] registers a devres callback on creation, which is called once the +/// [`Device`] is unbound, revoking access to the encapsulated resource (see also [`Revocable`]). +/// +/// After the [`Devres`] has been unbound it is not possible to access the encapsulated resource +/// anymore. +/// +/// [`Devres`] users should make sure to simply free the corresponding backing resource in `T`'s +/// [`Drop`] implementation. +/// +/// # Example +/// +/// ```no_run +/// # use kernel::{bindings, c_str, device::Device, devres::Devres, io::{Io, IoRaw}}; +/// # use core::ops::Deref; +/// +/// // See also [`pci::Bar`] for a real example. +/// struct IoMem(IoRaw); +/// +/// impl IoMem { +/// /// # Safety +/// /// +/// /// [`paddr`, `paddr` + `SIZE`) must be a valid MMIO region that is mappable into the CPUs +/// /// virtual address space. +/// unsafe fn new(paddr: usize) -> Result{ +/// // SAFETY: By the safety requirements of this function [`paddr`, `paddr` + `SIZE`) is +/// // valid for `ioremap`. +/// let addr = unsafe { bindings::ioremap(paddr as _, SIZE.try_into().unwrap()) }; +/// if addr.is_null() { +/// return Err(ENOMEM); +/// } +/// +/// Ok(IoMem(IoRaw::new(addr as _, SIZE)?)) +/// } +/// } +/// +/// impl Drop for IoMem { +/// fn drop(&mut self) { +/// // SAFETY: `self.0.addr()` is guaranteed to be properly mapped by `Self::new`. +/// unsafe { bindings::iounmap(self.0.addr() as _); }; +/// } +/// } +/// +/// impl Deref for IoMem { +/// type Target = Io; +/// +/// fn deref(&self) -> &Self::Target { +/// // SAFETY: The memory range stored in `self` has been properly mapped in `Self::new`. +/// unsafe { Io::from_raw(&self.0) } +/// } +/// } +/// # fn no_run() -> Result<(), Error> { +/// # // SAFETY: Invalid usage; just for the example to get an `ARef` instance. +/// # let dev = unsafe { Device::get_device(core::ptr::null_mut()) }; +/// +/// // SAFETY: Invalid usage for example purposes. +/// let iomem = unsafe { IoMem::<{ core::mem::size_of::() }>::new(0xBAAAAAAD)? }; +/// let devres = Devres::new(&dev, iomem, GFP_KERNEL)?; +/// +/// let res = devres.try_access().ok_or(ENXIO)?; +/// res.writel(0x42, 0x0); +/// # Ok(()) +/// # } +/// ``` +pub struct Devres(Arc>); + +impl DevresInner { + fn new(dev: &Device, data: T, flags: Flags) -> Result>> { + let inner = Arc::pin_init( + pin_init!( DevresInner { + data <- Revocable::new(data), + }), + flags, + )?; + + // Convert `Arc` into a raw pointer and make devres own this reference until + // `Self::devres_callback` is called. + let data = inner.clone().into_raw(); + + // SAFETY: `devm_add_action` guarantees to call `Self::devres_callback` once `dev` is + // detached. + let ret = unsafe { + bindings::devm_add_action(dev.as_raw(), Some(Self::devres_callback), data as _) + }; + + if ret != 0 { + // SAFETY: We just created another reference to `inner` in order to pass it to + // `bindings::devm_add_action`. If `bindings::devm_add_action` fails, we have to drop + // this reference accordingly. + let _ = unsafe { Arc::from_raw(data) }; + return Err(Error::from_errno(ret)); + } + + Ok(inner) + } + + #[allow(clippy::missing_safety_doc)] + unsafe extern "C" fn devres_callback(ptr: *mut c_void) { + let ptr = ptr as *mut DevresInner; + // Devres owned this memory; now that we received the callback, drop the `Arc` and hence the + // reference. + // SAFETY: Safe, since we leaked an `Arc` reference to devm_add_action() in + // `DevresInner::new`. + let inner = unsafe { Arc::from_raw(ptr) }; + + inner.data.revoke(); + } +} + +impl Devres { + /// Creates a new [`Devres`] instance of the given `data`. The `data` encapsulated within the + /// returned `Devres` instance' `data` will be revoked once the device is detached. + pub fn new(dev: &Device, data: T, flags: Flags) -> Result { + let inner = DevresInner::new(dev, data, flags)?; + + Ok(Devres(inner)) + } + + /// Same as [`Devres::new`], but does not return a `Devres` instance. Instead the given `data` + /// is owned by devres and will be revoked / dropped, once the device is detached. + pub fn new_foreign_owned(dev: &Device, data: T, flags: Flags) -> Result { + let _ = DevresInner::new(dev, data, flags)?; + + Ok(()) + } +} + +impl Deref for Devres { + type Target = Revocable; + + fn deref(&self) -> &Self::Target { + &self.0.data + } +} + +impl Drop for Devres { + fn drop(&mut self) { + // Revoke the data, such that it gets dropped already and the actual resource is freed. + // + // `DevresInner` has to stay alive until the devres callback has been called. This is + // necessary since we don't know when `Devres` is dropped and calling + // `devm_remove_action()` instead could race with `devres_release_all()`. + // + // SAFETY: When `drop` runs, it's guaranteed that nobody is accessing the revocable data + // anymore, hence it is safe not to wait for the grace period to finish. + unsafe { self.revoke_nosync() }; + } +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index d1f30b1a05fb..4b94e6072c63 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -41,6 +41,7 @@ pub mod cred; pub mod device; pub mod device_id; +pub mod devres; pub mod driver; pub mod error; #[cfg(CONFIG_RUST_FW_LOADER_ABSTRACTIONS)] From patchwork Thu Dec 5 14:14:39 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895433 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0531821A443; Thu, 5 Dec 2024 14:16:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408198; cv=none; b=htBXHjUOerKtk/ySIJew63gVyIkR8/3xYprAe0vxGQu0ptQ/tLkFLrCnWEHotj8vlU2EO5u5nzHGAdgtj13Zw9mqLYQY9JeENL030DSY812HWSVGR+9gWnKzLIzXhyFhW84WrQYh6HOz2xdhAIEThCKY03HWB9hHl8rQmU/gE38= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408198; c=relaxed/simple; bh=S/NNp+ME4+ZahmjytMhYjYxghROp7Wqi0tBDb/33WiI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MKQbb3bNJpwt8QU+Y/N3ELXdfcm/gfqsIRVgFyV04/g+jMPFh3H4xW0tiAzGp9gTDCz95H7nHAKBDuqytDigfdEsMGsHZhHml+wt9+u5ptjVEWwYcbIDcLtwnHKTYX2hlKkxr1sCmc7uFKBlXvANS97LkD5AVAtQNtqR4jxYeQI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Kv2GJVx3; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Kv2GJVx3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A8CB1C4CEDD; Thu, 5 Dec 2024 14:16:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408197; bh=S/NNp+ME4+ZahmjytMhYjYxghROp7Wqi0tBDb/33WiI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Kv2GJVx3U/r9KcOw6xfBp9DfNi+MTSCJPQkggLyBzUqaLXrMoGrKtn1GWD1ojhxq3 Qff6j7025VLhlm7ZjpAPQ19kIP3AvlUralyxvqVnMtfQG00yxoWgdVQBxb4lMrK5MD /KKagx7EaFrXF89x4ToCq//kbCJGVxF3fFzk+Lp5M+nFQPE8j+GQq0ryE6Yq3OvB8l j0md1c4N/2CUrsCUqtsQWqHTbYKxUUMQKb614DdfU5e2wD7xy7atdrLRX+FdbysipP an9Uae7teGi2kuzoQ3irRpBdEnMAoSZcO70hBse9thcLRCNxZuG1MwxxrZzeNIjlfa PreOxyrI7AtWg== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 08/13] rust: pci: add basic PCI device / driver abstractions Date: Thu, 5 Dec 2024 15:14:39 +0100 Message-ID: <20241205141533.111830-9-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement the basic PCI abstractions required to write a basic PCI driver. This includes the following data structures: The `pci::Driver` trait represents the interface to the driver and provides `pci::Driver::probe` for the driver to implement. The `pci::Device` abstraction represents a `struct pci_dev` and provides abstractions for common functions, such as `pci::Device::set_master`. In order to provide the PCI specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `pci::Adapter`. `pci::DeviceId` implements PCI device IDs based on the generic `device_id::RawDevceId` abstraction. Co-developed-by: FUJITA Tomonori Signed-off-by: FUJITA Tomonori Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 1 + rust/helpers/helpers.c | 1 + rust/helpers/pci.c | 18 ++ rust/kernel/lib.rs | 2 + rust/kernel/pci.rs | 284 ++++++++++++++++++++++++++++++++ 6 files changed, 307 insertions(+) create mode 100644 rust/helpers/pci.c create mode 100644 rust/kernel/pci.rs diff --git a/MAINTAINERS b/MAINTAINERS index a3535297ee6f..041b0c1b476f 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18099,6 +18099,7 @@ F: include/asm-generic/pci* F: include/linux/of_pci.h F: include/linux/pci* F: include/uapi/linux/pci* +F: rust/kernel/pci.rs PCIE BANDWIDTH CONTROLLER M: Ilpo Järvinen diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 5c4dfe22f41a..6d7a68e2ecb7 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -20,6 +20,7 @@ #include #include #include +#include #include #include #include diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index a3b52aa021de..3fda33cd42d4 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -20,6 +20,7 @@ #include "kunit.c" #include "mutex.c" #include "page.c" +#include "pci.c" #include "pid_namespace.c" #include "rbtree.c" #include "rcu.c" diff --git a/rust/helpers/pci.c b/rust/helpers/pci.c new file mode 100644 index 000000000000..8ba22f911459 --- /dev/null +++ b/rust/helpers/pci.c @@ -0,0 +1,18 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void rust_helper_pci_set_drvdata(struct pci_dev *pdev, void *data) +{ + pci_set_drvdata(pdev, data); +} + +void *rust_helper_pci_get_drvdata(struct pci_dev *pdev) +{ + return pci_get_drvdata(pdev); +} + +resource_size_t rust_helper_pci_resource_len(struct pci_dev *pdev, int bar) +{ + return pci_resource_len(pdev, bar); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 4b94e6072c63..07770add5ee2 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -82,6 +82,8 @@ pub use bindings; pub mod io; pub use macros; +#[cfg(all(CONFIG_PCI, CONFIG_PCI_MSI))] +pub mod pci; pub use uapi; #[doc(hidden)] diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs new file mode 100644 index 000000000000..748912c1c994 --- /dev/null +++ b/rust/kernel/pci.rs @@ -0,0 +1,284 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Abstractions for the PCI bus. +//! +//! C header: [`include/linux/pci.h`](srctree/include/linux/pci.h) + +use crate::{ + bindings, container_of, device, + device_id::RawDeviceId, + driver, + error::{to_result, Result}, + str::CStr, + types::{ARef, ForeignOwnable}, + ThisModule, +}; +use core::ops::Deref; +use kernel::prelude::*; + +/// An adapter for the registration of PCI drivers. +pub struct Adapter(T); + +impl driver::RegistrationOps for Adapter { + type RegType = bindings::pci_driver; + + fn register( + pdrv: &mut Self::RegType, + name: &'static CStr, + module: &'static ThisModule, + ) -> Result { + pdrv.name = name.as_char_ptr(); + pdrv.probe = Some(Self::probe_callback); + pdrv.remove = Some(Self::remove_callback); + pdrv.id_table = T::ID_TABLE.as_ptr(); + + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + to_result(unsafe { + bindings::__pci_register_driver(pdrv as _, module.0, name.as_char_ptr()) + }) + } + + fn unregister(pdrv: &mut Self::RegType) { + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + unsafe { bindings::pci_unregister_driver(pdrv) } + } +} + +impl Adapter { + extern "C" fn probe_callback( + pdev: *mut bindings::pci_dev, + id: *const bindings::pci_device_id, + ) -> core::ffi::c_int { + // SAFETY: The PCI bus only ever calls the probe callback with a valid pointer to a + // `struct pci_dev`. + let dev = unsafe { device::Device::get_device(&mut (*pdev).dev) }; + // SAFETY: `dev` is guaranteed to be embedded in a valid `struct pci_dev` by the call + // above. + let mut pdev = unsafe { Device::from_dev(dev) }; + + // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct pci_device_id` and + // does not add additional invariants, so it's safe to transmute. + let id = unsafe { &*id.cast::() }; + let info = T::ID_TABLE.info(id.index()); + + match T::probe(&mut pdev, id, info) { + Ok(data) => { + // Let the `struct pci_dev` own a reference of the driver's private data. + // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a + // `struct pci_dev`. + unsafe { bindings::pci_set_drvdata(pdev.as_raw(), data.into_foreign() as _) }; + } + Err(err) => return Error::to_errno(err), + } + + 0 + } + + extern "C" fn remove_callback(pdev: *mut bindings::pci_dev) { + // SAFETY: The PCI bus only ever calls the remove callback with a valid pointer to a + // `struct pci_dev`. + let ptr = unsafe { bindings::pci_get_drvdata(pdev) }; + + // SAFETY: `remove_callback` is only ever called after a successful call to + // `probe_callback`, hence it's guaranteed that `ptr` points to a valid and initialized + // `KBox` pointer created through `KBox::into_foreign`. + let _ = unsafe { KBox::::from_foreign(ptr) }; + } +} + +/// Declares a kernel module that exposes a single PCI driver. +/// +/// # Example +/// +///```ignore +/// kernel::module_pci_driver! { +/// type: MyDriver, +/// name: "Module name", +/// author: "Author name", +/// description: "Description", +/// license: "GPL v2", +/// } +///``` +#[macro_export] +macro_rules! module_pci_driver { +($($f:tt)*) => { + $crate::module_driver!(, $crate::pci::Adapter, { $($f)* }); +}; +} + +/// Abstraction for bindings::pci_device_id. +#[repr(transparent)] +#[derive(Clone, Copy)] +pub struct DeviceId(bindings::pci_device_id); + +impl DeviceId { + const PCI_ANY_ID: u32 = !0; + + /// PCI_DEVICE macro. + pub const fn new(vendor: u32, device: u32) -> Self { + Self(bindings::pci_device_id { + vendor, + device, + subvendor: DeviceId::PCI_ANY_ID, + subdevice: DeviceId::PCI_ANY_ID, + class: 0, + class_mask: 0, + driver_data: 0, + override_only: 0, + }) + } + + /// PCI_DEVICE_CLASS macro. + pub const fn with_class(class: u32, class_mask: u32) -> Self { + Self(bindings::pci_device_id { + vendor: DeviceId::PCI_ANY_ID, + device: DeviceId::PCI_ANY_ID, + subvendor: DeviceId::PCI_ANY_ID, + subdevice: DeviceId::PCI_ANY_ID, + class, + class_mask, + driver_data: 0, + override_only: 0, + }) + } +} + +// Allow drivers R/O access to the fields of `pci_device_id`; should we prefer accessor functions +// to void exposing C structure fields? +impl Deref for DeviceId { + type Target = bindings::pci_device_id; + + fn deref(&self) -> &Self::Target { + &self.0 + } +} + +// SAFETY: +// * `DeviceId` is a `#[repr(transparent)` wrapper of `pci_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. +// * `DRIVER_DATA_OFFSET` is the offset to the `driver_data` field. +unsafe impl RawDeviceId for DeviceId { + type RawType = bindings::pci_device_id; + + const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::pci_device_id, driver_data); + + fn index(&self) -> usize { + self.driver_data as _ + } +} + +/// IdTable type for PCI +pub type IdTable = &'static dyn kernel::device_id::IdTable; + +/// Create a PCI `IdTable` with its alias for modpost. +#[macro_export] +macro_rules! pci_device_table { + ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => { + const $table_name: $crate::device_id::IdArray< + $crate::pci::DeviceId, + $id_info_type, + { $table_data.len() }, + > = $crate::device_id::IdArray::new($table_data); + + $crate::module_device_table!("pci", $module_table_name, $table_name); + }; +} + +/// The PCI driver trait. +/// +/// # Example +/// +///``` +/// # use kernel::{bindings, pci}; +/// +/// struct MyDriver; +/// +/// kernel::pci_device_table!( +/// PCI_TABLE, +/// MODULE_PCI_TABLE, +/// ::IdInfo, +/// [ +/// (pci::DeviceId::new(bindings::PCI_VENDOR_ID_REDHAT, bindings::PCI_ANY_ID as u32), ()) +/// ] +/// ); +/// +/// impl pci::Driver for MyDriver { +/// type IdInfo = (); +/// const ID_TABLE: pci::IdTable = &PCI_TABLE; +/// +/// fn probe( +/// _pdev: &mut pci::Device, +/// _id: &pci::DeviceId, +/// _id_info: &Self::IdInfo, +/// ) -> Result>> { +/// Err(ENODEV) +/// } +/// } +///``` +/// Drivers must implement this trait in order to get a PCI driver registered. Please refer to the +/// `Adapter` documentation for an example. +pub trait Driver { + /// The type holding information about each device id supported by the driver. + /// + /// TODO: Use associated_type_defaults once stabilized: + /// + /// type IdInfo: 'static = (); + type IdInfo: 'static; + + /// The table of device ids supported by the driver. + const ID_TABLE: IdTable; + + /// PCI driver probe. + /// + /// Called when a new platform device is added or discovered. + /// Implementers should attempt to initialize the device here. + fn probe(dev: &mut Device, id: &DeviceId, id_info: &Self::IdInfo) -> Result>>; +} + +/// The PCI device representation. +/// +/// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI +/// device, hence, also increments the base device' reference count. +#[derive(Clone)] +pub struct Device(ARef); + +impl Device { + /// Create a PCI Device instance from an existing `device::Device`. + /// + /// # Safety + /// + /// `dev` must be an `ARef` whose underlying `bindings::device` is a member of + /// a `bindings::pci_dev`. + pub unsafe fn from_dev(dev: ARef) -> Self { + Self(dev) + } + + fn as_raw(&self) -> *mut bindings::pci_dev { + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` + // embedded in `struct pci_dev`. + unsafe { container_of!(self.0.as_raw(), bindings::pci_dev, dev) as _ } + } + + /// Enable memory resources for this device. + pub fn enable_device_mem(&self) -> Result { + // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. + let ret = unsafe { bindings::pci_enable_device_mem(self.as_raw()) }; + if ret != 0 { + Err(Error::from_errno(ret)) + } else { + Ok(()) + } + } + + /// Enable bus-mastering for this device. + pub fn set_master(&self) { + // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. + unsafe { bindings::pci_set_master(self.as_raw()) }; + } +} + +impl AsRef for Device { + fn as_ref(&self) -> &device::Device { + &self.0 + } +} From patchwork Thu Dec 5 14:14:40 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895434 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BC37F21A443; Thu, 5 Dec 2024 14:16:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408203; cv=none; b=HSB/g3b5etO5XLoT75xdo2d1nOwtxVIaty5W7c4MRtdM6m2F5JQbnnV6w1fv77OEG1n+bHQSPynH/u5kSyrsRhmWCxMoUTexwsN0IPDXXXjf3GPVklb9qL1YVrq4AtSzDCWrLOX5Q1X1XClVX5p9Zp0QV++i5YYAP5F5nH2l2Co= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408203; c=relaxed/simple; bh=GlyHYcr/5hUUC7pwO997T8baSWmx4aL+aOQmqKa4cmE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lwXQTAjkRwSJBlvuZNUEhMt8r8PcECNlYjLlKXU7AzU/gchkdsKFSZQ4USpYSp12ciMj0glDZMLdDp8zcPmDkJ0UGkxYy1Ft7y4v1N4EqTLBQ+lsNYD3IGSZKoXTLvRhfvgqMWF48PkN026Qy+P6eTYD7h+/JAYg4z3wF9lvcLc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ps4nIQGJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ps4nIQGJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB2CAC4CEDF; Thu, 5 Dec 2024 14:16:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408203; bh=GlyHYcr/5hUUC7pwO997T8baSWmx4aL+aOQmqKa4cmE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ps4nIQGJ5xzdleOXymmGREXLB1lh1UbD6wcf7In3n8r1ZuQvlCDyovzcF1WP1h96C Rmnrg23BHuu6CGjFlisLkuls8jmdwfj/G1DE2aTNWxmUpOPNt7agk3E0CrnRU815bZ K4oH+H0voJyOECC7UOfHlCr0JgT2Oe9Au1aBmeyV28i/nktyDv8aD6cmQ3cKNJLuLb VRx0WSlnxAsKwZxIhTINKaL/CspoofXHft5nynDdP7X+GTWZLTt/Ijiod/15qQehXB yhjbHMRs2WqofLhUKBo7aR9DWJ9UwAY/DQtBpT35R68VglCnJV++Z7Y2DaxNnN5D6y WkMGRI5A44OQw== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 09/13] rust: pci: implement I/O mappable `pci::Bar` Date: Thu, 5 Dec 2024 15:14:40 +0100 Message-ID: <20241205141533.111830-10-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement `pci::Bar`, `pci::Device::iomap_region` and `pci::Device::iomap_region_sized` to allow for I/O mappings of PCI BARs. To ensure that a `pci::Bar`, and hence the I/O memory mapping, can't out-live the PCI device, the `pci::Bar` type is always embedded into a `Devres` container, such that the `pci::Bar` is revoked once the device is unbound and hence the I/O mapped memory is unmapped. A `pci::Bar` can be requested with (`pci::Device::iomap_region_sized`) or without (`pci::Device::iomap_region`) a const generic representing the minimal requested size of the I/O mapped memory region. In case of the latter only runtime checked I/O reads / writes are possible. Co-developed-by: Philipp Stanner Signed-off-by: Philipp Stanner Signed-off-by: Danilo Krummrich --- rust/kernel/pci.rs | 145 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 145 insertions(+) diff --git a/rust/kernel/pci.rs b/rust/kernel/pci.rs index 748912c1c994..0a32a5935c9c 100644 --- a/rust/kernel/pci.rs +++ b/rust/kernel/pci.rs @@ -5,10 +5,14 @@ //! C header: [`include/linux/pci.h`](srctree/include/linux/pci.h) use crate::{ + alloc::flags::*, bindings, container_of, device, device_id::RawDeviceId, + devres::Devres, driver, error::{to_result, Result}, + io::Io, + io::IoRaw, str::CStr, types::{ARef, ForeignOwnable}, ThisModule, @@ -239,9 +243,115 @@ pub trait Driver { /// /// A PCI device is based on an always reference counted `device:Device` instance. Cloning a PCI /// device, hence, also increments the base device' reference count. +/// +/// # Invariants +/// +/// `Device` hold a valid reference of `ARef` whose underlying `struct device` is a +/// member of a `struct pci_dev`. #[derive(Clone)] pub struct Device(ARef); +/// A PCI BAR to perform I/O-Operations on. +/// +/// # Invariants +/// +/// `Bar` always holds an `IoRaw` inststance that holds a valid pointer to the start of the I/O +/// memory mapped PCI bar and its size. +pub struct Bar { + pdev: Device, + io: IoRaw, + num: i32, +} + +impl Bar { + fn new(pdev: Device, num: u32, name: &CStr) -> Result { + let len = pdev.resource_len(num)?; + if len == 0 { + return Err(ENOMEM); + } + + // Convert to `i32`, since that's what all the C bindings use. + let num = i32::try_from(num)?; + + // SAFETY: + // `pdev` is valid by the invariants of `Device`. + // `num` is checked for validity by a previous call to `Device::resource_len`. + // `name` is always valid. + let ret = unsafe { bindings::pci_request_region(pdev.as_raw(), num, name.as_char_ptr()) }; + if ret != 0 { + return Err(EBUSY); + } + + // SAFETY: + // `pdev` is valid by the invariants of `Device`. + // `num` is checked for validity by a previous call to `Device::resource_len`. + // `name` is always valid. + let ioptr: usize = unsafe { bindings::pci_iomap(pdev.as_raw(), num, 0) } as usize; + if ioptr == 0 { + // SAFETY: + // `pdev` valid by the invariants of `Device`. + // `num` is checked for validity by a previous call to `Device::resource_len`. + unsafe { bindings::pci_release_region(pdev.as_raw(), num) }; + return Err(ENOMEM); + } + + let io = match IoRaw::new(ioptr, len as usize) { + Ok(io) => io, + Err(err) => { + // SAFETY: + // `pdev` is valid by the invariants of `Device`. + // `ioptr` is guaranteed to be the start of a valid I/O mapped memory region. + // `num` is checked for validity by a previous call to `Device::resource_len`. + unsafe { Self::do_release(&pdev, ioptr, num) }; + return Err(err); + } + }; + + Ok(Bar { pdev, io, num }) + } + + /// # Safety + /// + /// `ioptr` must be a valid pointer to the memory mapped PCI bar number `num`. + unsafe fn do_release(pdev: &Device, ioptr: usize, num: i32) { + // SAFETY: + // `pdev` is valid by the invariants of `Device`. + // `ioptr` is valid by the safety requirements. + // `num` is valid by the safety requirements. + unsafe { + bindings::pci_iounmap(pdev.as_raw(), ioptr as _); + bindings::pci_release_region(pdev.as_raw(), num); + } + } + + fn release(&self) { + // SAFETY: The safety requirements are guaranteed by the type invariant of `self.pdev`. + unsafe { Self::do_release(&self.pdev, self.io.addr(), self.num) }; + } +} + +impl Bar { + fn index_is_valid(index: u32) -> bool { + // A `struct pci_dev` owns an array of resources with at most `PCI_NUM_RESOURCES` entries. + index < bindings::PCI_NUM_RESOURCES + } +} + +impl Drop for Bar { + fn drop(&mut self) { + self.release(); + } +} + +impl Deref for Bar { + type Target = Io; + + fn deref(&self) -> &Self::Target { + // SAFETY: By the type invariant of `Self`, the MMIO range in `self.io` is properly mapped. + unsafe { Io::from_raw(&self.io) } + } +} + impl Device { /// Create a PCI Device instance from an existing `device::Device`. /// @@ -275,6 +385,41 @@ pub fn set_master(&self) { // SAFETY: `self.as_raw` is guaranteed to be a pointer to a valid `struct pci_dev`. unsafe { bindings::pci_set_master(self.as_raw()) }; } + + /// Returns the size of the given PCI bar resource. + pub fn resource_len(&self, bar: u32) -> Result { + if !Bar::index_is_valid(bar) { + return Err(EINVAL); + } + + // SAFETY: + // - `bar` is a valid bar number, as guaranteed by the above call to `Bar::index_is_valid`, + // - by its type invariant `self.as_raw` is always a valid pointer to a `struct pci_dev`. + Ok(unsafe { bindings::pci_resource_len(self.as_raw(), bar.try_into()?) }) + } + + /// Mapps an entire PCI-BAR after performing a region-request on it. I/O operation bound checks + /// can be performed on compile time for offsets (plus the requested type size) < SIZE. + pub fn iomap_region_sized( + &self, + bar: u32, + name: &CStr, + ) -> Result>> { + let bar = Bar::::new(self.clone(), bar, name)?; + let devres = Devres::new(self.as_ref(), bar, GFP_KERNEL)?; + + Ok(devres) + } + + /// Mapps an entire PCI-BAR after performing a region-request on it. + pub fn iomap_region(&self, bar: u32, name: &CStr) -> Result> { + self.iomap_region_sized::<0>(bar, name) + } + + /// Returns a new `ARef` of the base `device::Device`. + pub fn as_dev(&self) -> ARef { + self.0.clone() + } } impl AsRef for Device { From patchwork Thu Dec 5 14:14:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895435 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 281F421A431; Thu, 5 Dec 2024 14:16:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408210; cv=none; b=f9/Gzu3uSv6y6YpvXB3HmeS0YvLK978yj8IWLgeeFyo7/eGxFP3YQJ4wfWCREKZD+oKYgWCgMW2yf1aww5WvnJqLH3qFazFoz84IcCXBJT7/LY6OpLmaIaYbkUTC8tXeTXHRwiHWvlPxIA50kTiXPG1znHaQQtgBobYMEPxMvzE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408210; c=relaxed/simple; bh=9lJ7gKW/axA9Y9tGKn4BNE3/DgwHFkjbttlWcj6o/JQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=RCz8dZsVsAQl8d4rIoEFHrl2jQFX5rlkBeHQev0a8/XgCbJU3GocexU71BwBWoR1LI+Dg5bBDG+13O+SqF+ZW6KkKiDyz3UPhMkqUxo3G/CwPmm89NgXHR5fBAo0lEse7vHCmiYx+AjzktArwUrwU+qWe2YidG0PpBrC0NnoPX0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Y8zP1UI7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Y8zP1UI7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1A7BBC4CED1; Thu, 5 Dec 2024 14:16:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408209; bh=9lJ7gKW/axA9Y9tGKn4BNE3/DgwHFkjbttlWcj6o/JQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Y8zP1UI7LMSD0Zyyyfzp0qgqJ6LG4W1uZwq9vbq4dYzLp3yQilAtTzqYtPfq8j40z 466bev1Y+I2phOQDReZhu/cWEZaO8hqwRN74pfVyradmE5pXR/5l0yb6uzpX/MSZdz Qiwla0waO06FFYSC+lT/w+WImRt6EkVxeFRYLcFjFw+IaarpXxcE5Po9T1RKEIQKuK 16Fg0c4PJcd3hUppnSdWMsiTRyCvgrERTAH0qe/sE+w4ljIz3inQunQJfbmCT+Pqh7 PRQiTaumrFYa0ZytOVaBg1PUUW6h2Qjz1YoHDxf3S8wYMS8j+TirTgtzRsAwtAJTX2 dAETWoqecXj1g== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 10/13] samples: rust: add Rust PCI sample driver Date: Thu, 5 Dec 2024 15:14:41 +0100 Message-ID: <20241205141533.111830-11-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 This commit adds a sample Rust PCI driver for QEMU's "pci-testdev" device. To enable this device QEMU has to be called with `-device pci-testdev`. The same driver shows how to use the PCI device / driver abstractions, as well as how to request and map PCI BARs, including a short sequence of MMIO operations. Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + samples/rust/Kconfig | 11 ++++ samples/rust/Makefile | 1 + samples/rust/rust_driver_pci.rs | 109 ++++++++++++++++++++++++++++++++ 4 files changed, 122 insertions(+) create mode 100644 samples/rust/rust_driver_pci.rs diff --git a/MAINTAINERS b/MAINTAINERS index 041b0c1b476f..f97052d5f454 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -18100,6 +18100,7 @@ F: include/linux/of_pci.h F: include/linux/pci* F: include/uapi/linux/pci* F: rust/kernel/pci.rs +F: samples/rust/rust_driver_pci.rs PCIE BANDWIDTH CONTROLLER M: Ilpo Järvinen diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig index b0f74a81c8f9..6d468193cdd8 100644 --- a/samples/rust/Kconfig +++ b/samples/rust/Kconfig @@ -30,6 +30,17 @@ config SAMPLE_RUST_PRINT If unsure, say N. +config SAMPLE_RUST_DRIVER_PCI + tristate "PCI Driver" + depends on PCI + help + This option builds the Rust PCI driver sample. + + To compile this as a module, choose M here: + the module will be called driver_pci. + + If unsure, say N. + config SAMPLE_RUST_HOSTPROGS bool "Host programs" help diff --git a/samples/rust/Makefile b/samples/rust/Makefile index c1a5c1655395..2f5b6bdb2fa5 100644 --- a/samples/rust/Makefile +++ b/samples/rust/Makefile @@ -3,6 +3,7 @@ ccflags-y += -I$(src) # needed for trace events obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o +obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o rust_print-y := rust_print_main.o rust_print_events.o diff --git a/samples/rust/rust_driver_pci.rs b/samples/rust/rust_driver_pci.rs new file mode 100644 index 000000000000..76d742189c00 --- /dev/null +++ b/samples/rust/rust_driver_pci.rs @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust PCI driver sample (based on QEMU's `pci-testdev`). +//! +//! To make this driver probe, QEMU must be run with `-device pci-testdev`. + +use kernel::{bindings, c_str, devres::Devres, pci, prelude::*}; + +struct Regs; + +impl Regs { + const TEST: usize = 0x0; + const OFFSET: usize = 0x4; + const DATA: usize = 0x8; + const COUNT: usize = 0xC; + const END: usize = 0x10; +} + +type Bar0 = pci::Bar<{ Regs::END }>; + +#[derive(Debug)] +struct TestIndex(u8); + +impl TestIndex { + const NO_EVENTFD: Self = Self(0); +} + +struct SampleDriver { + pdev: pci::Device, + bar: Devres, +} + +kernel::pci_device_table!( + PCI_TABLE, + MODULE_PCI_TABLE, + ::IdInfo, + [( + pci::DeviceId::new(bindings::PCI_VENDOR_ID_REDHAT, 0x5), + TestIndex::NO_EVENTFD + )] +); + +impl SampleDriver { + fn testdev(index: &TestIndex, bar: &Bar0) -> Result { + // Select the test. + bar.writeb(index.0, Regs::TEST); + + let offset = u32::from_le(bar.readl(Regs::OFFSET)) as usize; + let data = bar.readb(Regs::DATA); + + // Write `data` to `offset` to increase `count` by one. + // + // Note that we need `try_writeb`, since `offset` can't be checked at compile-time. + bar.try_writeb(data, offset)?; + + Ok(bar.readl(Regs::COUNT)) + } +} + +impl pci::Driver for SampleDriver { + type IdInfo = TestIndex; + + const ID_TABLE: pci::IdTable = &PCI_TABLE; + + fn probe( + pdev: &mut pci::Device, + _id: &pci::DeviceId, + info: &Self::IdInfo, + ) -> Result>> { + dev_dbg!(pdev.as_ref(), "Probe Rust PCI driver sample.\n"); + + pdev.enable_device_mem()?; + pdev.set_master(); + + let bar = pdev.iomap_region_sized::<{ Regs::END }>(0, c_str!("rust_driver_pci"))?; + + let drvdata = KBox::new( + Self { + pdev: pdev.clone(), + bar, + }, + GFP_KERNEL, + )?; + + let bar = drvdata.bar.try_access().ok_or(ENXIO)?; + + dev_info!( + pdev.as_ref(), + "pci-testdev data-match count: {}\n", + Self::testdev(info, &bar)? + ); + + Ok(drvdata.into()) + } +} + +impl Drop for SampleDriver { + fn drop(&mut self) { + dev_dbg!(self.pdev.as_ref(), "Remove Rust PCI driver sample.\n"); + } +} + +kernel::module_pci_driver! { + type: SampleDriver, + name: "rust_driver_pci", + author: "Danilo Krummrich", + description: "Rust PCI driver", + license: "GPL v2", +} From patchwork Thu Dec 5 14:14:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895436 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7B9F321C165; Thu, 5 Dec 2024 14:16:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408216; cv=none; b=X6OEL0BoQpfIrcjnkwKUHFKpgA1jPuhbbWz9RIza0sSSK/lHxigon2mhOQohgPcTP4aSWi25ieoGPB+V9qs1EZHyUWuZ+43/347gf7ihuaMFWfM0BaWnd1k+6gQU5mEVl+EWPkPTatfNzwiMDjx2QCOSHhPOBZWCo4yDsx6Hrik= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408216; c=relaxed/simple; bh=u7p5w3YMf9jp+upkdyNIlDdEvty8OlJvf0CytCuomJk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PM1lxUGh3qDy8hcmDWVpkwfxqCd6JYiUy28AEItDlS3Y8tVmSc5AnAsOIJ6QfV+gJgI9bi7Pj0UfKygzUHCZlWfrnDrd2TrqBR9V4e/NGLMkY/Tf3otRD+uOW856BJys+LJBRXu2NyXYgUSYO2wHf6/Tx9bnHk1aUuUK2/gs7A4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WhsR5ULe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WhsR5ULe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D8AEC4CEDD; Thu, 5 Dec 2024 14:16:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408216; bh=u7p5w3YMf9jp+upkdyNIlDdEvty8OlJvf0CytCuomJk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WhsR5ULeOhna4l7gmxDSaxy0AOHo8LB5wvNWGNCrkU9FbebOrHpDNDsvtRjNFdge6 Xws4MtF2RvHZkAvFpD1+OEPaBB4DGHqMae1YwRNm63uV8JMV555uZzJk8w/FT3LtGM l6OoxSI8hEiAWgYzjpid58lmzpVupe6InuUyfe5TUIK9UDLxbYzqnueccCi3B4hlsB hUeRMHupuvruOxNQAcTi5SO3MF600oBU1+BBFcOwSKjuFM0OjBPNB6mmn4RwK9lyBi UptyOrZoTHHRadDhpXZ+mTpnG6CwDaBe4HqeHOrSnOdCn0sgGxV3UpYd+1akdJb5j6 tGzOfPuL2288A== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 11/13] rust: of: add `of::DeviceId` abstraction Date: Thu, 5 Dec 2024 15:14:42 +0100 Message-ID: <20241205141533.111830-12-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 `of::DeviceId` is an abstraction around `struct of_device_id`. This is used by subsequent patches, in particular the platform bus abstractions, to create OF device ID tables. Signed-off-by: Danilo Krummrich Reviewed-by: Rob Herring (Arm) --- MAINTAINERS | 1 + rust/kernel/lib.rs | 1 + rust/kernel/of.rs | 57 ++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 59 insertions(+) create mode 100644 rust/kernel/of.rs diff --git a/MAINTAINERS b/MAINTAINERS index f97052d5f454..7d6bb4b15d2c 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -17499,6 +17499,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux.git F: Documentation/ABI/testing/sysfs-firmware-ofw F: drivers/of/ F: include/linux/of*.h +F: rust/kernel/of.rs F: scripts/dtc/ F: tools/testing/selftests/dt/ K: of_overlay_notifier_ diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 07770add5ee2..7a0e4c82ad0c 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -56,6 +56,7 @@ pub mod miscdevice; #[cfg(CONFIG_NET)] pub mod net; +pub mod of; pub mod page; pub mod pid_namespace; pub mod prelude; diff --git a/rust/kernel/of.rs b/rust/kernel/of.rs new file mode 100644 index 000000000000..2b424f3bfa93 --- /dev/null +++ b/rust/kernel/of.rs @@ -0,0 +1,57 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Device Tree / Open Firmware abstractions. + +use crate::{bindings, device_id::RawDeviceId, prelude::*}; + +/// An open firmware device id. +#[repr(transparent)] +#[derive(Clone, Copy)] +pub struct DeviceId(bindings::of_device_id); + +// SAFETY: +// * `DeviceId` is a `#[repr(transparent)` wrapper of `struct of_device_id` and does not add +// additional invariants, so it's safe to transmute to `RawType`. +// * `DRIVER_DATA_OFFSET` is the offset to the `data` field. +unsafe impl RawDeviceId for DeviceId { + type RawType = bindings::of_device_id; + + const DRIVER_DATA_OFFSET: usize = core::mem::offset_of!(bindings::of_device_id, data); + + fn index(&self) -> usize { + self.0.data as _ + } +} + +impl DeviceId { + /// Create a new device id from an OF 'compatible' string. + pub const fn new(compatible: &'static CStr) -> Self { + let src = compatible.as_bytes_with_nul(); + // Replace with `bindings::of_device_id::default()` once stabilized for `const`. + // SAFETY: FFI type is valid to be zero-initialized. + let mut of: bindings::of_device_id = unsafe { core::mem::zeroed() }; + + // TODO: Use `clone_from_slice` once the corresponding types do match. + let mut i = 0; + while i < src.len() { + of.compatible[i] = src[i] as _; + i += 1; + } + + Self(of) + } +} + +/// Create an OF `IdTable` with an "alias" for modpost. +#[macro_export] +macro_rules! of_device_table { + ($table_name:ident, $module_table_name:ident, $id_info_type: ty, $table_data: expr) => { + const $table_name: $crate::device_id::IdArray< + $crate::of::DeviceId, + $id_info_type, + { $table_data.len() }, + > = $crate::device_id::IdArray::new($table_data); + + $crate::module_device_table!("of", $module_table_name, $table_name); + }; +} From patchwork Thu Dec 5 14:14:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895437 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5FB6A21C16B; Thu, 5 Dec 2024 14:17:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408222; cv=none; b=hrBL2U2VIoVI/NvCwvPlxVo587miJd+DFmRUFGzdI+5OVeWqR9IG5ol/kjtnf3gT5S6mKtQ3voP4mJfaqcdfelmMC86KXfXcl844aJX4NCyyp6PuCZdqTRHtgE1zHEn/r87sYEB2kxNJXb7fBxSH0XYD5lZOU/meHRWvjvkoO6s= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408222; c=relaxed/simple; bh=IKX0O1SrOLKu4uiz9usnuC5uo2WtQ/eZrUtXJqx7Uuw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aoaqKIWHJI9AaW2PLdo6dQDrFSv4SeQHp36N88WKDzzVY5TBXfmTDmOeAa2EFK5Y5uyTH1LJjBIIPlZvvTAHVwf101u5olPsKN9RT3+6Warjlg3bwYEiJS3vjZWacCCRuCFfKprXSvQ42d42pgqaVrlszQ/xNhzUGl/QwHZ6z8c= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f/xbT5r7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="f/xbT5r7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F908C4CED1; Thu, 5 Dec 2024 14:16:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408222; bh=IKX0O1SrOLKu4uiz9usnuC5uo2WtQ/eZrUtXJqx7Uuw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f/xbT5r7dNQ3h6Ewx/n+VlsWzprXiUE2LYdpTH8F1Mcu9dEk6QbUE2TMYYCzg8cF6 VOZXJSdqxbrG4OeAbGSb7jHENHw97LHG5v+ywWiyVKhH8UPSagXFxqGCQsfrA+X4b2 fJyKli1PgRbI+GsYgoofWS6rJjbRk1b2TyUohulY/KjrBR4gN3XAEqskCuz62EEEos K7hYGRVYUvkeer0rs8o4yYQrU95ClOZWSo4Jc3LaYnubQPxSeyF9DylIiHvJewCPRt sVOOERL8cjZh2/bhV48dHB44y2Z9hUrRJ+OF/quv4rzH9kqgE8VrLoI2UqMqyQc6Td 0/Au/fEZ2COBQ== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 12/13] rust: platform: add basic platform device / driver abstractions Date: Thu, 5 Dec 2024 15:14:43 +0100 Message-ID: <20241205141533.111830-13-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Implement the basic platform bus abstractions required to write a basic platform driver. This includes the following data structures: The `platform::Driver` trait represents the interface to the driver and provides `pci::Driver::probe` for the driver to implement. The `platform::Device` abstraction represents a `struct platform_device`. In order to provide the platform bus specific parts to a generic `driver::Registration` the `driver::RegistrationOps` trait is implemented by `platform::Adapter`. Signed-off-by: Danilo Krummrich --- MAINTAINERS | 1 + rust/bindings/bindings_helper.h | 2 + rust/helpers/helpers.c | 1 + rust/helpers/platform.c | 13 ++ rust/kernel/lib.rs | 1 + rust/kernel/platform.rs | 222 ++++++++++++++++++++++++++++++++ 6 files changed, 240 insertions(+) create mode 100644 rust/helpers/platform.c create mode 100644 rust/kernel/platform.rs diff --git a/MAINTAINERS b/MAINTAINERS index 7d6bb4b15d2c..365fc48b7041 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7034,6 +7034,7 @@ F: rust/kernel/device.rs F: rust/kernel/device_id.rs F: rust/kernel/devres.rs F: rust/kernel/driver.rs +F: rust/kernel/platform.rs DRIVERS FOR OMAP ADAPTIVE VOLTAGE SCALING (AVS) M: Nishanth Menon diff --git a/rust/bindings/bindings_helper.h b/rust/bindings/bindings_helper.h index 6d7a68e2ecb7..e9fdceb568b8 100644 --- a/rust/bindings/bindings_helper.h +++ b/rust/bindings/bindings_helper.h @@ -20,9 +20,11 @@ #include #include #include +#include #include #include #include +#include #include #include #include diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c index 3fda33cd42d4..0640b7e115be 100644 --- a/rust/helpers/helpers.c +++ b/rust/helpers/helpers.c @@ -20,6 +20,7 @@ #include "kunit.c" #include "mutex.c" #include "page.c" +#include "platform.c" #include "pci.c" #include "pid_namespace.c" #include "rbtree.c" diff --git a/rust/helpers/platform.c b/rust/helpers/platform.c new file mode 100644 index 000000000000..ab9b9f317301 --- /dev/null +++ b/rust/helpers/platform.c @@ -0,0 +1,13 @@ +// SPDX-License-Identifier: GPL-2.0 + +#include + +void *rust_helper_platform_get_drvdata(const struct platform_device *pdev) +{ + return platform_get_drvdata(pdev); +} + +void rust_helper_platform_set_drvdata(struct platform_device *pdev, void *data) +{ + platform_set_drvdata(pdev, data); +} diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs index 7a0e4c82ad0c..cc8f48aa162b 100644 --- a/rust/kernel/lib.rs +++ b/rust/kernel/lib.rs @@ -59,6 +59,7 @@ pub mod of; pub mod page; pub mod pid_namespace; +pub mod platform; pub mod prelude; pub mod print; pub mod rbtree; diff --git a/rust/kernel/platform.rs b/rust/kernel/platform.rs new file mode 100644 index 000000000000..868cfddb75a2 --- /dev/null +++ b/rust/kernel/platform.rs @@ -0,0 +1,222 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Abstractions for the platform bus. +//! +//! C header: [`include/linux/platform_device.h`](srctree/include/linux/platform_device.h) + +use crate::{ + bindings, container_of, device, driver, + error::{to_result, Result}, + of, + prelude::*, + str::CStr, + types::{ARef, ForeignOwnable}, + ThisModule, +}; + +/// An adapter for the registration of platform drivers. +pub struct Adapter(T); + +impl driver::RegistrationOps for Adapter { + type RegType = bindings::platform_driver; + + fn register( + pdrv: &mut Self::RegType, + name: &'static CStr, + module: &'static ThisModule, + ) -> Result { + pdrv.driver.name = name.as_char_ptr(); + pdrv.probe = Some(Self::probe_callback); + + // Both members of this union are identical in data layout and semantics. + pdrv.__bindgen_anon_1.remove = Some(Self::remove_callback); + pdrv.driver.of_match_table = T::OF_ID_TABLE.as_ptr(); + + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + to_result(unsafe { bindings::__platform_driver_register(pdrv, module.0) }) + } + + fn unregister(pdrv: &mut Self::RegType) { + // SAFETY: `pdrv` is guaranteed to be a valid `RegType`. + unsafe { bindings::platform_driver_unregister(pdrv) }; + } +} + +impl Adapter { + #[cfg(CONFIG_OF)] + fn of_id_info(pdev: &Device) -> Option<&'static T::IdInfo> { + let table = T::OF_ID_TABLE; + + // SAFETY: + // - `table` has static lifetime, hence it's valid for read, + // - `dev` is guaranteed to be valid while it's alive, and so is `pdev.as_ref().as_raw()`. + let raw_id = unsafe { bindings::of_match_device(table.as_ptr(), pdev.as_ref().as_raw()) }; + + if raw_id.is_null() { + None + } else { + // SAFETY: `DeviceId` is a `#[repr(transparent)` wrapper of `struct of_device_id` and + // does not add additional invariants, so it's safe to transmute. + let id = unsafe { &*raw_id.cast::() }; + + Some(table.info(::index(id))) + } + } + + #[cfg(not(CONFIG_OF))] + fn of_id_info(_pdev: &Device) -> Option<&'static T::IdInfo> { + None + } + + // Try to retrieve an `IdInfo` from any of the ID tables; if we can't find one for a particular + // table, it means we don't have a match in there. If we don't match any of the ID tables, it + // means we were matched by name. + fn id_info(pdev: &Device) -> Option<&'static T::IdInfo> { + let id = Self::of_id_info(pdev); + if id.is_some() { + return id; + } + + None + } + + extern "C" fn probe_callback(pdev: *mut bindings::platform_device) -> core::ffi::c_int { + // SAFETY: The platform bus only ever calls the probe callback with a valid `pdev`. + let dev = unsafe { device::Device::get_device(&mut (*pdev).dev) }; + // SAFETY: `dev` is guaranteed to be embedded in a valid `struct platform_device` by the + // call above. + let mut pdev = unsafe { Device::from_dev(dev) }; + + let info = Self::id_info(&pdev); + match T::probe(&mut pdev, info) { + Ok(data) => { + // Let the `struct platform_device` own a reference of the driver's private data. + // SAFETY: By the type invariant `pdev.as_raw` returns a valid pointer to a + // `struct platform_device`. + unsafe { bindings::platform_set_drvdata(pdev.as_raw(), data.into_foreign() as _) }; + } + Err(err) => return Error::to_errno(err), + } + + 0 + } + + extern "C" fn remove_callback(pdev: *mut bindings::platform_device) { + // SAFETY: `pdev` is a valid pointer to a `struct platform_device`. + let ptr = unsafe { bindings::platform_get_drvdata(pdev) }; + + // SAFETY: `remove_callback` is only ever called after a successful call to + // `probe_callback`, hence it's guaranteed that `ptr` points to a valid and initialized + // `KBox` pointer created through `KBox::into_foreign`. + let _ = unsafe { KBox::::from_foreign(ptr) }; + } +} + +/// Declares a kernel module that exposes a single platform driver. +/// +/// # Examples +/// +/// ```ignore +/// kernel::module_platform_driver! { +/// type: MyDriver, +/// name: "Module name", +/// author: "Author name", +/// description: "Description", +/// license: "GPL v2", +/// } +/// ``` +#[macro_export] +macro_rules! module_platform_driver { + ($($f:tt)*) => { + $crate::module_driver!(, $crate::platform::Adapter, { $($f)* }); + }; +} + +/// IdTable type for platform drivers. +pub type IdTable = &'static dyn kernel::device_id::IdTable; + +/// The platform driver trait. +/// +/// Drivers must implement this trait in order to get a platform driver registered. +/// +/// # Example +/// +///``` +/// # use kernel::{bindings, c_str, of, platform}; +/// +/// struct MyDriver; +/// +/// kernel::of_device_table!( +/// OF_TABLE, +/// MODULE_OF_TABLE, +/// ::IdInfo, +/// [ +/// (of::DeviceId::new(c_str!("test,device")), ()) +/// ] +/// ); +/// +/// impl platform::Driver for MyDriver { +/// type IdInfo = (); +/// const OF_ID_TABLE: platform::IdTable = &OF_TABLE; +/// +/// fn probe( +/// _pdev: &mut platform::Device, +/// _id_info: Option<&Self::IdInfo>, +/// ) -> Result>> { +/// Err(ENODEV) +/// } +/// } +///``` +pub trait Driver { + /// The type holding information about each device id supported by the driver. + /// + /// TODO: Use associated_type_defaults once stabilized: + /// + /// type IdInfo: 'static = (); + type IdInfo: 'static; + + /// The table of OF device ids supported by the driver. + const OF_ID_TABLE: IdTable; + + /// Platform driver probe. + /// + /// Called when a new platform device is added or discovered. + /// Implementers should attempt to initialize the device here. + fn probe(dev: &mut Device, id_info: Option<&Self::IdInfo>) -> Result>>; +} + +/// The platform device representation. +/// +/// A platform device is based on an always reference counted `device:Device` instance. Cloning a +/// platform device, hence, also increments the base device' reference count. +/// +/// # Invariants +/// +/// `Device` holds a valid reference of `ARef` whose underlying `struct device` is a +/// member of a `struct platform_device`. +#[derive(Clone)] +pub struct Device(ARef); + +impl Device { + /// Convert a raw kernel device into a `Device` + /// + /// # Safety + /// + /// `dev` must be an `Aref` whose underlying `bindings::device` is a member of a + /// `bindings::platform_device`. + unsafe fn from_dev(dev: ARef) -> Self { + Self(dev) + } + + fn as_raw(&self) -> *mut bindings::platform_device { + // SAFETY: By the type invariant `self.0.as_raw` is a pointer to the `struct device` + // embedded in `struct platform_device`. + unsafe { container_of!(self.0.as_raw(), bindings::platform_device, dev) }.cast_mut() + } +} + +impl AsRef for Device { + fn as_ref(&self) -> &device::Device { + &self.0 + } +} From patchwork Thu Dec 5 14:14:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Danilo Krummrich X-Patchwork-Id: 13895438 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E2C24218EB3; Thu, 5 Dec 2024 14:17:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408229; cv=none; b=KIXGTSBJKUfL7CrYPGchgxcE6fZdZL0eqmVm3Qt4zy0zXQYjihart/q5s5o8vIVx/s33u006anEtv5aNRXxP5vsn6PcBd68sDLCfOq6MxYdmiuqUi8iSoXJZqtLZ+JzPtwDsxscJmuBtXmh95ZWTj5avRHMf1DsHpx9eKaOUmsY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733408229; c=relaxed/simple; bh=fsQdz0uOY3RAQ4rMNOpTqBJdkc/b5ZHxcuQQNj6yVKY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=m2nL+hPhS285aRURRejP+XCejoxS1DT6ke818fCI03AjOzau0PBD9sA7GAa4vaWa8tSV1sk2oTEW/tVfWE9Bvf4II8vCR5XlB4/r1JNkAwWWVymHK29BpUM6eH9klERA1z4hpSPsEqSr0qYkJ5OHzJZBiUxyrMH5Eds9hOlKhmc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=nT5X3/xV; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="nT5X3/xV" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2260C4CEDD; Thu, 5 Dec 2024 14:17:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733408228; bh=fsQdz0uOY3RAQ4rMNOpTqBJdkc/b5ZHxcuQQNj6yVKY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nT5X3/xVaG1myUIf1wLCdym2Y9V3Sf3p5wOv2x9IYsy9XnjjhQrpAVnz/eZPRLY82 BbYpb2ulLUxw4GhSOBuiMffANdbtK6aQyQX1AD3vOYOBv0KVekV0kL0OXXX6s3f7LE OHLidjzdQScMnvBifMFdth5Abv4Cq0z6KN3kGDQ8eW5MRxOVUZTfB8ut9/OxE1aVQL c9OrM68JTAN3Csz2VZSPUWZhLvZIsPUmO6rUGyIAELoVytYTZY/A8IiAxJD4csMDut 3WeVutfpdZwQQk8JSbzbaIEatUx1kliJfPxrENxvrlkFI+bymtaDcGjcE7N5FWyKVW OETqWu4kpSEDg== From: Danilo Krummrich To: gregkh@linuxfoundation.org, rafael@kernel.org, bhelgaas@google.com, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, tmgross@umich.edu, a.hindborg@samsung.com, aliceryhl@google.com, airlied@gmail.com, fujita.tomonori@gmail.com, lina@asahilina.net, pstanner@redhat.com, ajanulgu@redhat.com, lyude@redhat.com, robh@kernel.org, daniel.almeida@collabora.com, saravanak@google.com, dirk.behme@de.bosch.com, j@jannau.net, fabien.parent@linaro.org, chrisi.schrefl@gmail.com Cc: rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, Danilo Krummrich Subject: [PATCH v4 13/13] samples: rust: add Rust platform sample driver Date: Thu, 5 Dec 2024 15:14:44 +0100 Message-ID: <20241205141533.111830-14-dakr@kernel.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241205141533.111830-1-dakr@kernel.org> References: <20241205141533.111830-1-dakr@kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Add a sample Rust platform driver illustrating the usage of the platform bus abstractions. This driver probes through either a match of device / driver name or a match within the OF ID table. Signed-off-by: Danilo Krummrich Reviewed-by: Rob Herring (Arm) --- MAINTAINERS | 1 + drivers/of/unittest-data/tests-platform.dtsi | 5 ++ samples/rust/Kconfig | 10 ++++ samples/rust/Makefile | 1 + samples/rust/rust_driver_platform.rs | 49 ++++++++++++++++++++ 5 files changed, 66 insertions(+) create mode 100644 samples/rust/rust_driver_platform.rs diff --git a/MAINTAINERS b/MAINTAINERS index 365fc48b7041..ae576c842c51 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -7035,6 +7035,7 @@ F: rust/kernel/device_id.rs F: rust/kernel/devres.rs F: rust/kernel/driver.rs F: rust/kernel/platform.rs +F: samples/rust/rust_driver_platform.rs DRIVERS FOR OMAP ADAPTIVE VOLTAGE SCALING (AVS) M: Nishanth Menon diff --git a/drivers/of/unittest-data/tests-platform.dtsi b/drivers/of/unittest-data/tests-platform.dtsi index fa39611071b3..2caaf1c10ee6 100644 --- a/drivers/of/unittest-data/tests-platform.dtsi +++ b/drivers/of/unittest-data/tests-platform.dtsi @@ -33,6 +33,11 @@ dev@100 { reg = <0x100>; }; }; + + test-device@2 { + compatible = "test,rust-device"; + reg = <0x2>; + }; }; }; }; diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig index 6d468193cdd8..70126b750426 100644 --- a/samples/rust/Kconfig +++ b/samples/rust/Kconfig @@ -41,6 +41,16 @@ config SAMPLE_RUST_DRIVER_PCI If unsure, say N. +config SAMPLE_RUST_DRIVER_PLATFORM + tristate "Platform Driver" + help + This option builds the Rust Platform driver sample. + + To compile this as a module, choose M here: + the module will be called rust_driver_platform. + + If unsure, say N. + config SAMPLE_RUST_HOSTPROGS bool "Host programs" help diff --git a/samples/rust/Makefile b/samples/rust/Makefile index 2f5b6bdb2fa5..761d13fff018 100644 --- a/samples/rust/Makefile +++ b/samples/rust/Makefile @@ -4,6 +4,7 @@ ccflags-y += -I$(src) # needed for trace events obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o obj-$(CONFIG_SAMPLE_RUST_DRIVER_PCI) += rust_driver_pci.o +obj-$(CONFIG_SAMPLE_RUST_DRIVER_PLATFORM) += rust_driver_platform.o rust_print-y := rust_print_main.o rust_print_events.o diff --git a/samples/rust/rust_driver_platform.rs b/samples/rust/rust_driver_platform.rs new file mode 100644 index 000000000000..2f0dbbe69e10 --- /dev/null +++ b/samples/rust/rust_driver_platform.rs @@ -0,0 +1,49 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Rust Platform driver sample. + +use kernel::{c_str, of, platform, prelude::*}; + +struct SampleDriver { + pdev: platform::Device, +} + +struct Info(u32); + +kernel::of_device_table!( + OF_TABLE, + MODULE_OF_TABLE, + ::IdInfo, + [(of::DeviceId::new(c_str!("test,rust-device")), Info(42))] +); + +impl platform::Driver for SampleDriver { + type IdInfo = Info; + const OF_ID_TABLE: platform::IdTable = &OF_TABLE; + + fn probe(pdev: &mut platform::Device, info: Option<&Self::IdInfo>) -> Result>> { + dev_dbg!(pdev.as_ref(), "Probe Rust Platform driver sample.\n"); + + if let Some(info) = info { + dev_info!(pdev.as_ref(), "Probed with info: '{}'.\n", info.0); + } + + let drvdata = KBox::new(Self { pdev: pdev.clone() }, GFP_KERNEL)?; + + Ok(drvdata.into()) + } +} + +impl Drop for SampleDriver { + fn drop(&mut self) { + dev_dbg!(self.pdev.as_ref(), "Remove Rust Platform driver sample.\n"); + } +} + +kernel::module_platform_driver! { + type: SampleDriver, + name: "rust_driver_platform", + author: "Danilo Krummrich", + description: "Rust Platform driver", + license: "GPL v2", +}