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[2620:137:e000::1:20]) by mx.google.com with ESMTP id jw6-20020a170903278600b0019ab3eb21fesi11740643plb.72.2023.03.07.06.34.28; Tue, 07 Mar 2023 06:34:41 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@asahilina.net header.s=default header.b=pQIUoDU+; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=asahilina.net Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230011AbjCGOcf (ORCPT + 99 others); Tue, 7 Mar 2023 09:32:35 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230406AbjCGObg (ORCPT ); Tue, 7 Mar 2023 09:31:36 -0500 Received: from mail.marcansoft.com (marcansoft.com [212.63.210.85]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 403081E9C9; Tue, 7 Mar 2023 06:27:34 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: linasend@asahilina.net) by mail.marcansoft.com (Postfix) with ESMTPSA id E7AF6424EB; Tue, 7 Mar 2023 14:27:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=asahilina.net; s=default; t=1678199252; bh=tiuyBWTl8Qdxvj79LVgsGFbR06YAjmOHoitbb98rzLA=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=pQIUoDU+zvY4rYeN9Otpg73BvCX394ybfNniG50+pCGTU/dRQzMT0GNTyCUTJcoaF RuCPNmEqUTzp0gTrn+45EXTK7X2QBEnupjZrbnmdsvEZPpih7MsFnL5QFTX8FW7Kc9 9VGU1FQjOdn2u08IylzPfQb120kGPd4BjesZwebSTj1+waUoiNLJUenkhaY6jZQ92s ozWFKoHyKSYwPX//CtaLhNDUABDjXC7dgtbgB83UozvJ0nGDFxMk/yIyutNqihzeDx eWtOIqOkRibkTJxe3W27ePR7Rn1BbGEWj0B3nqb0CUwX3+/XSl9hrfIh1f6CudPzC2 a2Q0ItXbVVq7g== From: Asahi Lina Date: Tue, 07 Mar 2023 23:25:32 +0900 Subject: [PATCH RFC 07/18] rust: drm: mm: Add DRM MM Range Allocator abstraction MIME-Version: 1.0 Message-Id: <20230307-rust-drm-v1-7-917ff5bc80a8@asahilina.net> References: <20230307-rust-drm-v1-0-917ff5bc80a8@asahilina.net> In-Reply-To: <20230307-rust-drm-v1-0-917ff5bc80a8@asahilina.net> To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Miguel Ojeda , Alex Gaynor , Wedson Almeida Filho , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Sumit Semwal , =?utf-8?q?Christian_K=C3=B6nig?= , Luben Tuikov , Jarkko Sakkinen , Dave Hansen Cc: Alyssa Rosenzweig , Karol Herbst , Ella Stanforth , Faith Ekstrand , Mary , linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, rust-for-linux@vger.kernel.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-sgx@vger.kernel.org, asahi@lists.linux.dev, Asahi Lina X-Mailer: b4 0.12.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1678199191; l=11527; i=lina@asahilina.net; s=20230221; h=from:subject:message-id; bh=tiuyBWTl8Qdxvj79LVgsGFbR06YAjmOHoitbb98rzLA=; b=1YWNy7i7Y7pqn4yADDd+wawlXS8A7BCpNq2HvNp13CJ6/glYN+hiWD6duc+ImAlFB7hpC4Nj5 qKVdeJNweZNBkjTZR9M7ZwRdGs9mp0ON/OFHohmu5CGOmuAhGYSEnZ9 X-Developer-Key: i=lina@asahilina.net; a=ed25519; pk=Qn8jZuOtR1m5GaiDfTrAoQ4NE1XoYVZ/wmt5YtXWFC4= X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1759719909196510501?= X-GMAIL-MSGID: =?utf-8?q?1759719909196510501?= drm_mm provides a simple range allocator, useful for managing virtual address ranges. Add a Rust abstraction to expose this module to Rust drivers. Signed-off-by: Asahi Lina --- rust/kernel/drm/mm.rs | 309 +++++++++++++++++++++++++++++++++++++++++++++++++ rust/kernel/drm/mod.rs | 1 + 2 files changed, 310 insertions(+) diff --git a/rust/kernel/drm/mm.rs b/rust/kernel/drm/mm.rs new file mode 100644 index 000000000000..83e27a7dcc7e --- /dev/null +++ b/rust/kernel/drm/mm.rs @@ -0,0 +1,309 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT + +//! DRM MM range allocator +//! +//! C header: [`include/linux/drm/drm_mm.h`](../../../../include/linux/drm/drm_mm.h) + +use crate::{ + bindings, + error::{to_result, Result}, + str::CStr, + sync::{Arc, LockClassKey, LockIniter, Mutex, UniqueArc}, + types::Opaque, +}; + +use alloc::boxed::Box; + +use core::{ + marker::{PhantomData, PhantomPinned}, + ops::Deref, + pin::Pin, +}; + +/// Type alias representing a DRM MM node. +pub type Node = Pin>>; + +/// Trait which must be implemented by the inner allocator state type provided by the user. +pub trait AllocInner { + /// Notification that a node was dropped from the allocator. + fn drop_object(&mut self, _start: u64, _size: u64, _color: usize, _object: &mut T) {} +} + +impl AllocInner for () {} + +/// Wrapper type for a `struct drm_mm` plus user AllocInner object. +/// +/// # Invariants +/// The `drm_mm` struct is valid and initialized. +struct MmInner, T>(Opaque, A, PhantomData); + +/// Represents a single allocated node in the MM allocator +pub struct NodeData, T> { + node: bindings::drm_mm_node, + mm: Arc>>, + valid: bool, + /// A drm_mm_node needs to be pinned because nodes reference each other in a linked list. + _pin: PhantomPinned, + inner: T, +} + +// SAFETY: Allocator ops take the mutex, and there are no mutable actions on the node. +unsafe impl, T: Send> Send for NodeData {} +unsafe impl, T: Sync> Sync for NodeData {} + +/// Available MM node insertion modes +#[repr(u32)] +pub enum InsertMode { + /// Search for the smallest hole (within the search range) that fits the desired node. + /// + /// Allocates the node from the bottom of the found hole. + Best = bindings::drm_mm_insert_mode_DRM_MM_INSERT_BEST, + + /// Search for the lowest hole (address closest to 0, within the search range) that fits the + /// desired node. + /// + /// Allocates the node from the bottom of the found hole. + Low = bindings::drm_mm_insert_mode_DRM_MM_INSERT_LOW, + + /// Search for the highest hole (address closest to U64_MAX, within the search range) that fits + /// the desired node. + /// + /// Allocates the node from the top of the found hole. The specified alignment for the node is + /// applied to the base of the node (`Node.start()`). + High = bindings::drm_mm_insert_mode_DRM_MM_INSERT_HIGH, + + /// Search for the most recently evicted hole (within the search range) that fits the desired + /// node. This is appropriate for use immediately after performing an eviction scan and removing + /// the selected nodes to form a hole. + /// + /// Allocates the node from the bottom of the found hole. + Evict = bindings::drm_mm_insert_mode_DRM_MM_INSERT_EVICT, +} + +/// A clonable, interlocked reference to the allocator state. +/// +/// This is useful to perform actions on the user-supplied `AllocInner` type given just a Node, +/// without immediately taking the lock. +#[derive(Clone)] +pub struct InnerRef, T>(Arc>>); + +impl, T> InnerRef { + /// Operate on the user `AllocInner` implementation, taking the lock. + pub fn with(&self, cb: impl FnOnce(&mut A) -> RetVal) -> RetVal { + let mut l = self.0.lock(); + cb(&mut l.1) + } +} + +impl, T> NodeData { + /// Returns the color of the node (an opaque value) + pub fn color(&self) -> usize { + self.node.color as usize + } + + /// Returns the start address of the node + pub fn start(&self) -> u64 { + self.node.start + } + + /// Returns the size of the node in bytes + pub fn size(&self) -> u64 { + self.node.size + } + + /// Operate on the user `AllocInner` implementation associated with this node's allocator. + pub fn with_inner(&self, cb: impl FnOnce(&mut A) -> RetVal) -> RetVal { + let mut l = self.mm.lock(); + cb(&mut l.1) + } + + /// Return a clonable, detached reference to the allocator inner data. + pub fn alloc_ref(&self) -> InnerRef { + InnerRef(self.mm.clone()) + } + + /// Return a mutable reference to the inner data. + pub fn inner_mut(self: Pin<&mut Self>) -> &mut T { + // SAFETY: This is okay because inner is not structural + unsafe { &mut self.get_unchecked_mut().inner } + } +} + +impl, T> Deref for NodeData { + type Target = T; + + fn deref(&self) -> &Self::Target { + &self.inner + } +} + +impl, T> Drop for NodeData { + fn drop(&mut self) { + if self.valid { + let mut guard = self.mm.lock(); + + // Inform the user allocator that a node is being dropped. + guard + .1 + .drop_object(self.start(), self.size(), self.color(), &mut self.inner); + // SAFETY: The MM lock is still taken, so we can safely remove the node. + unsafe { bindings::drm_mm_remove_node(&mut self.node) }; + } + } +} + +/// An instance of a DRM MM range allocator. +pub struct Allocator, T> { + mm: Arc>>, + _p: PhantomData, +} + +impl, T> Allocator { + /// Create a new range allocator for the given start and size range of addresses. + /// + /// The user may optionally provide an inner object representing allocator state, which will + /// be protected by the same lock. If not required, `()` can be used. + pub fn new( + start: u64, + size: u64, + inner: A, + name: &'static CStr, + lock_key: &'static LockClassKey, + ) -> Result> { + // SAFETY: We call `Mutex::init_lock` below. + let mut mm: Pin>>> = UniqueArc::try_new(unsafe { + Mutex::new(MmInner(Opaque::uninit(), inner, PhantomData)) + })? + .into(); + + mm.as_mut().init_lock(name, lock_key); + + unsafe { + // SAFETY: The Opaque instance provides a valid pointer, and it is initialized after + // this call. + bindings::drm_mm_init(mm.lock().0.get(), start, size); + } + + Ok(Allocator { + mm: mm.into(), + _p: PhantomData, + }) + } + + /// Insert a new node into the allocator of a given size. + /// + /// `node` is the user `T` type data to store into the node. + pub fn insert_node(&mut self, node: T, size: u64) -> Result> { + self.insert_node_generic(node, size, 0, 0, InsertMode::Best) + } + + /// Insert a new node into the allocator of a given size, with configurable alignment, + /// color, and insertion mode. + /// + /// `node` is the user `T` type data to store into the node. + pub fn insert_node_generic( + &mut self, + node: T, + size: u64, + alignment: u64, + color: usize, + mode: InsertMode, + ) -> Result> { + self.insert_node_in_range(node, size, alignment, color, 0, u64::MAX, mode) + } + + /// Insert a new node into the allocator of a given size, with configurable alignment, + /// color, insertion mode, and sub-range to allocate from. + /// + /// `node` is the user `T` type data to store into the node. + #[allow(clippy::too_many_arguments)] + pub fn insert_node_in_range( + &mut self, + node: T, + size: u64, + alignment: u64, + color: usize, + start: u64, + end: u64, + mode: InsertMode, + ) -> Result> { + let mut mm_node = Box::try_new(NodeData { + // SAFETY: This C struct should be zero-initialized. + node: unsafe { core::mem::zeroed() }, + valid: false, + inner: node, + mm: self.mm.clone(), + _pin: PhantomPinned, + })?; + + let guard = self.mm.lock(); + // SAFETY: We hold the lock and all pointers are valid. + to_result(unsafe { + bindings::drm_mm_insert_node_in_range( + guard.0.get(), + &mut mm_node.node, + size, + alignment, + color as core::ffi::c_ulong, + start, + end, + mode as u32, + ) + })?; + + mm_node.valid = true; + + Ok(Pin::from(mm_node)) + } + + /// Insert a node into the allocator at a fixed start address. + /// + /// `node` is the user `T` type data to store into the node. + pub fn reserve_node( + &mut self, + node: T, + start: u64, + size: u64, + color: usize, + ) -> Result> { + let mut mm_node = Box::try_new(NodeData { + // SAFETY: This C struct should be zero-initialized. + node: unsafe { core::mem::zeroed() }, + valid: false, + inner: node, + mm: self.mm.clone(), + _pin: PhantomPinned, + })?; + + mm_node.node.start = start; + mm_node.node.size = size; + mm_node.node.color = color as core::ffi::c_ulong; + + let guard = self.mm.lock(); + // SAFETY: We hold the lock and all pointers are valid. + to_result(unsafe { bindings::drm_mm_reserve_node(guard.0.get(), &mut mm_node.node) })?; + + mm_node.valid = true; + + Ok(Pin::from(mm_node)) + } + + /// Operate on the inner user type `A`, taking the allocator lock + pub fn with_inner(&self, cb: impl FnOnce(&mut A) -> RetVal) -> RetVal { + let mut guard = self.mm.lock(); + cb(&mut guard.1) + } +} + +impl, T> Drop for MmInner { + fn drop(&mut self) { + // SAFETY: If the MmInner is dropped then all nodes are gone (since they hold references), + // so it is safe to tear down the allocator. + unsafe { + bindings::drm_mm_takedown(self.0.get()); + } + } +} + +// MmInner is safely Send if the AllocInner user type is Send. +unsafe impl, T> Send for MmInner {} diff --git a/rust/kernel/drm/mod.rs b/rust/kernel/drm/mod.rs index c44760a1332f..73fab2dee3af 100644 --- a/rust/kernel/drm/mod.rs +++ b/rust/kernel/drm/mod.rs @@ -7,3 +7,4 @@ pub mod drv; pub mod file; pub mod gem; pub mod ioctl; +pub mod mm;