From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sender4-pp-f112.zoho.com (sender4-pp-f112.zoho.com [136.143.188.112]) (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 1E87A22A813; Tue, 3 Jun 2025 15:06:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=pass smtp.client-ip=136.143.188.112 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748963207; cv=pass; b=W/gcyIKKeifw1oXOcdgG7DdWzQgHxMezQPz/vgx3ecilN68r45G0n6yjp9BKM+elFbcglzLtRrP5dNqNM7B3ICEyulefTjSFZ9398VAIBjn4RZd5C6r/8T6x0h40+FL7/3sqchTEORG412mlyDgQWvRmDqcvfq8WjDTURxb2gAQ= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748963207; c=relaxed/simple; bh=eLjKllphdx9D9dVx/N8mD3nHYKl+fZN252MJd5iFBqs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=n5sIBDLSWFtzW4MgYosoooXhYOqh8+TjaJQbsD/WjHTUWHE8vhi77i3S0OAWfhbHLbjts/8mVf8eB2nuD23HSu2x3ZkUPl1qLSPZF0ZSRQ1OxRIx4eZqnjcdDBB2aYtd9bORo4luZWhW8qAxdaVR64WelofawOBwERctl4Xxhho= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (1024-bit key) header.d=collabora.com header.i=daniel.almeida@collabora.com header.b=hqUAMUFf; arc=pass smtp.client-ip=136.143.188.112 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=collabora.com header.i=daniel.almeida@collabora.com header.b="hqUAMUFf" ARC-Seal: i=1; a=rsa-sha256; t=1748963182; cv=none; d=zohomail.com; s=zohoarc; b=d7j9Qp/gj1od7h26bQfjh69o4/6T3GA4uLeIh0QHwqkTtde88lsUIdEIcNxk6GG34hppMw0+c7THT7sVOHTayYf87mHxk8mmK0b+O8ePIlFv+i9F84xSgHkcLkXE17RPi1Iai8/cKpp/U3GO6JqO4KjPjxGoUdZv5YXnS5qV4/c= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1748963182; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:Subject:To:To:Message-Id:Reply-To; bh=2uyj7NIVcWkTF2iRk/SFYpp1aLvAuNsvuv8ite9SmzE=; b=lbNSnfyL3dggUm9gcjLXK1eyC1GQUQ03f6QlYosyi9SkggQ6iYprmOxlHHQ65mVvuMKszyx2Csediuk1mBEsltFoOsKKjiPp0Rp96uQm3paqZJRRm0djBrSWaQ7MBs2zVa4ni0xBop7b0fynRSj0bH9d//JSILbw4Sbu2vuXRq8= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=collabora.com; spf=pass smtp.mailfrom=daniel.almeida@collabora.com; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1748963182; s=zohomail; d=collabora.com; i=daniel.almeida@collabora.com; h=From:From:Date:Date:Subject:Subject:MIME-Version:Content-Type:Content-Transfer-Encoding:Message-Id:Message-Id:References:In-Reply-To:To:To:Cc:Cc:Reply-To; bh=2uyj7NIVcWkTF2iRk/SFYpp1aLvAuNsvuv8ite9SmzE=; b=hqUAMUFfmb2fyw7JRyinCUlELSfOOSxF6fl4SGEDUQsQ4LCuR4i0dKcPMpqiiVdu dsc9Ae/U8k4K9YoFoxnu1jXK4H7ghLJDwoqQaNg03GwK7FxPMH+AzOSRijV5pevIYRE r4+rSCVu9fhmVIw3Ko4lpxhSPCCMEl3GGv3crCHo= Received: by mx.zohomail.com with SMTPS id 1748963180462299.34861723796234; Tue, 3 Jun 2025 08:06:20 -0700 (PDT) From: Daniel Almeida Date: Tue, 03 Jun 2025 12:05:28 -0300 Subject: [PATCH v9 2/4] rust: io: mem: add a generic iomem abstraction Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20250603-topics-tyr-platform_iomem-v9-2-a27e04157e3e@collabora.com> References: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> In-Reply-To: <20250603-topics-tyr-platform_iomem-v9-0-a27e04157e3e@collabora.com> To: Miguel Ojeda , Alex Gaynor , Boqun Feng , Gary Guo , =?utf-8?q?Bj=C3=B6rn_Roy_Baron?= , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , Greg Kroah-Hartman , "Rafael J. Wysocki" , Andrew Morton , Andy Shevchenko , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Bjorn Helgaas , Mika Westerberg , Ying Huang Cc: linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org, Daniel Almeida X-Mailer: b4 0.14.2 X-ZohoMailClient: External Add a generic iomem abstraction to safely read and write ioremapped regions. The reads and writes are done through IoRaw, and are thus checked either at compile-time, if the size of the region is known at that point, or at runtime otherwise. Non-exclusive access to the underlying memory region is made possible to cater to cases where overlapped regions are unavoidable. Signed-off-by: Daniel Almeida --- rust/helpers/io.c | 5 ++ rust/kernel/io.rs | 1 + rust/kernel/io/mem.rs | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 148 insertions(+) diff --git a/rust/helpers/io.c b/rust/helpers/io.c index 939ab38ca61dac4cf884677a20edc760094d5812..4fbd70ab60f64155bef835a43b3c64d441aee7bf 100644 --- a/rust/helpers/io.c +++ b/rust/helpers/io.c @@ -8,6 +8,11 @@ void __iomem *rust_helper_ioremap(phys_addr_t offset, size_t size) return ioremap(offset, size); } +void __iomem *rust_helper_ioremap_np(phys_addr_t offset, size_t size) +{ + return ioremap_np(offset, size); +} + void rust_helper_iounmap(volatile void __iomem *addr) { iounmap(addr); diff --git a/rust/kernel/io.rs b/rust/kernel/io.rs index 1da447078633e058000953a581b59d3ed5eb0e69..0249aedd8c6ce435b6b00137be0895a206956bca 100644 --- a/rust/kernel/io.rs +++ b/rust/kernel/io.rs @@ -7,6 +7,7 @@ use crate::error::{code::EINVAL, Result}; use crate::{bindings, build_assert}; +pub mod mem; pub mod resource; /// Raw representation of an MMIO region. diff --git a/rust/kernel/io/mem.rs b/rust/kernel/io/mem.rs new file mode 100644 index 0000000000000000000000000000000000000000..2bd9cf4c4f1a59f027999a6e9a203dc99ad6c003 --- /dev/null +++ b/rust/kernel/io/mem.rs @@ -0,0 +1,142 @@ +// SPDX-License-Identifier: GPL-2.0 + +//! Generic memory-mapped IO. + +use core::ops::Deref; + +use crate::device::Bound; +use crate::device::Device; +use crate::devres::Devres; +use crate::io; +use crate::io::resource::Region; +use crate::io::resource::Resource; +use crate::io::Io; +use crate::io::IoRaw; +use crate::prelude::*; + +/// An exclusive memory-mapped IO region. +/// +/// # Invariants +/// +/// - [`ExclusiveIoMem`] has exclusive access to the underlying [`IoMem`]. +pub struct ExclusiveIoMem { + /// The region abstraction. This represents exclusive access to the + /// range represented by the underlying `iomem`. + /// + /// It's placed first to ensure that the region is released before it is + /// unmapped as a result of the drop order. + /// + /// This field is needed for ownership of the region. + _region: Region, + /// The underlying `IoMem` instance. + iomem: IoMem, +} + +impl ExclusiveIoMem { + /// Creates a new `ExclusiveIoMem` instance. + pub(crate) fn ioremap(resource: &Resource) -> Result { + let iomem = IoMem::ioremap(resource)?; + + let start = resource.start(); + let size = resource.size(); + let name = resource.name(); + + let region = resource + .request_region(start, size, name, io::resource::flags::IORESOURCE_MEM) + .ok_or(EBUSY)?; + + let iomem = ExclusiveIoMem { + iomem, + _region: region, + }; + + Ok(iomem) + } + + pub(crate) fn new(resource: &Resource, device: &Device) -> Result> { + let iomem = Self::ioremap(resource)?; + let devres = Devres::new(device, iomem, GFP_KERNEL)?; + + Ok(devres) + } +} + +impl Deref for ExclusiveIoMem { + type Target = Io; + + fn deref(&self) -> &Self::Target { + &self.iomem + } +} + +/// A generic memory-mapped IO region. +/// +/// Accesses to the underlying region is checked either at compile time, if the +/// region's size is known at that point, or at runtime otherwise. +/// +/// # Invariants +/// +/// [`IoMem`] always holds an [`IoRaw`] instance that holds a valid pointer to the +/// start of the I/O memory mapped region. +pub struct IoMem { + io: IoRaw, +} + +impl IoMem { + fn ioremap(resource: &Resource) -> Result { + let size = resource.size(); + if size == 0 { + return Err(EINVAL); + } + + let res_start = resource.start(); + + let addr = if resource + .flags() + .contains(io::resource::flags::IORESOURCE_MEM_NONPOSTED) + { + // SAFETY: + // - `res_start` and `size` are read from a presumably valid `struct resource`. + // - `size` is known not to be zero at this point. + unsafe { bindings::ioremap_np(res_start, size as usize) } + } else { + // SAFETY: + // - `res_start` and `size` are read from a presumably valid `struct resource`. + // - `size` is known not to be zero at this point. + unsafe { bindings::ioremap(res_start, size as usize) } + }; + + if addr.is_null() { + return Err(ENOMEM); + } + + let io = IoRaw::new(addr as usize, size as usize)?; + let io = IoMem { io }; + + Ok(io) + } + + /// Creates a new `IoMem` instance. + pub(crate) fn new(resource: &Resource, device: &Device) -> Result> { + let io = Self::ioremap(resource)?; + let devres = Devres::new(device, io, GFP_KERNEL)?; + + Ok(devres) + } +} + +impl Drop for IoMem { + fn drop(&mut self) { + // SAFETY: Safe as by the invariant of `Io`. + unsafe { bindings::iounmap(self.io.addr() as *mut core::ffi::c_void) } + } +} + +impl Deref for IoMem { + type Target = Io; + + fn deref(&self) -> &Self::Target { + // SAFETY: Safe as by the invariant of `IoMem`. + unsafe { Io::from_raw(&self.io) } + } +} -- 2.49.0