From mboxrd@z Thu Jan 1 00:00:00 1970 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 465651D5149; Thu, 5 Dec 2024 09:26:25 +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=1733390786; cv=none; b=jcMqRwlvLnziLPAhoTr/lhjrsXL7DZVXlkUvZo/KOJEn9UL1j8ql4OVpoXVgZwTksWVqe802WkUSQ+5djBgBoZyDwq98TMCc04wW9xvEj6J5d2mdO74NFHauSZOG9byPEqUDVqx6Yxsgp1JxLA8BL9hYVhX1cy08lZ24HVacYUo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733390786; c=relaxed/simple; bh=G0Io6HRP/GtjXQ5mHEb9WOF/mEVuGUzmcwvORugLAyA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YMMmgea3KSpnF5D+STR8+U17AEHbKfOmxG3el7aym12FdIP244WvfI5IQnp2hrv/AQZT5LCO+2pu338O2vkdyFb6+s84SaALIV0zFV9SMg9huPoIoYZw3JarPGFjKHa7qXYLJOIPZWYDVmYoFyvDIiR61jB5UZStA0zt18Y/gOA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=u/z1eRJe; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="u/z1eRJe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 317DFC4CED1; Thu, 5 Dec 2024 09:26:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1733390785; bh=G0Io6HRP/GtjXQ5mHEb9WOF/mEVuGUzmcwvORugLAyA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=u/z1eRJeRZN9NvyfzeI4PdzFM2FJ5AZqtsHlC9zlhasvt+gZc5DTWaHgDY7H5yFz6 zotSPussZJZnThcs+yr0n/GPHTTPJDWH6KzaIGeNoZxi8QqJTwbD8OlrZLPSpXBNeY uRLFx3eEvk6hhq9uRJSIXEZ/xDF7uWTB4gJ7nIfk= Date: Thu, 5 Dec 2024 10:26:22 +0100 From: Greg KH To: Lee Jones Cc: linux-kernel@vger.kernel.org, ojeda@kernel.org, alex.gaynor@gmail.com, boqun.feng@gmail.com, gary@garyguo.net, bjorn3_gh@protonmail.com, benno.lossin@proton.me, a.hindborg@kernel.org, aliceryhl@google.com, tmgross@umich.edu, rust-for-linux@vger.kernel.org Subject: Re: [PATCH 1/2] samples: rust: Provide example using the new Rust MiscDevice abstraction Message-ID: <2024120543-mutiny-blank-2c9b@gregkh> References: <20241204174627.1151288-1-lee@kernel.org> <2024120427-scurvy-fidgety-06fc@gregkh> <20241205084101.GE7451@google.com> <2024120543-bauble-semicolon-639d@gregkh> <20241205091704.GF7451@google.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241205091704.GF7451@google.com> On Thu, Dec 05, 2024 at 09:17:04AM +0000, Lee Jones wrote: > On Thu, 05 Dec 2024, Greg KH wrote: > > > On Thu, Dec 05, 2024 at 08:41:01AM +0000, Lee Jones wrote: > > > On Wed, 04 Dec 2024, Greg KH wrote: > > > > > > > On Wed, Dec 04, 2024 at 05:46:24PM +0000, Lee Jones wrote: > > > > > This sample driver demonstrates the following basic operations: > > > > > > > > > > * Register a Misc Device > > > > > * Create /dev/rust-misc-device > > > > > * Open the aforementioned character device > > > > > * Operate on the character device via a simple ioctl() > > > > > * Close the character device > > > > > > > > > > Signed-off-by: Lee Jones > > > > > --- > > > > > samples/rust/Kconfig | 10 ++++ > > > > > samples/rust/Makefile | 1 + > > > > > samples/rust/rust_misc_device.rs | 84 ++++++++++++++++++++++++++++++++ > > > > > 3 files changed, 95 insertions(+) > > > > > create mode 100644 samples/rust/rust_misc_device.rs > > > > > > > > > > diff --git a/samples/rust/Kconfig b/samples/rust/Kconfig > > > > > index b0f74a81c8f9..df384e679901 100644 > > > > > --- a/samples/rust/Kconfig > > > > > +++ b/samples/rust/Kconfig > > > > > @@ -20,6 +20,16 @@ config SAMPLE_RUST_MINIMAL > > > > > > > > > > If unsure, say N. > > > > > > > > > > +config SAMPLE_RUST_MISC_DEVICE > > > > > + tristate "Misc device" > > > > > + help > > > > > + This option builds the Rust misc device. > > > > > + > > > > > + To compile this as a module, choose M here: > > > > > + the module will be called rust_misc_device. > > > > > + > > > > > + If unsure, say N. > > > > > + > > > > > config SAMPLE_RUST_PRINT > > > > > tristate "Printing macros" > > > > > help > > > > > diff --git a/samples/rust/Makefile b/samples/rust/Makefile > > > > > index c1a5c1655395..ad4b97a98580 100644 > > > > > --- a/samples/rust/Makefile > > > > > +++ b/samples/rust/Makefile > > > > > @@ -2,6 +2,7 @@ > > > > > ccflags-y += -I$(src) # needed for trace events > > > > > > > > > > obj-$(CONFIG_SAMPLE_RUST_MINIMAL) += rust_minimal.o > > > > > +obj-$(CONFIG_SAMPLE_RUST_MISC_DEVICE) += rust_misc_device.o > > > > > obj-$(CONFIG_SAMPLE_RUST_PRINT) += rust_print.o > > > > > > > > > > rust_print-y := rust_print_main.o rust_print_events.o > > > > > diff --git a/samples/rust/rust_misc_device.rs b/samples/rust/rust_misc_device.rs > > > > > new file mode 100644 > > > > > index 000000000000..5f1b69569ef7 > > > > > --- /dev/null > > > > > +++ b/samples/rust/rust_misc_device.rs > > > > > @@ -0,0 +1,84 @@ > > > > > +// SPDX-License-Identifier: GPL-2.0 > > > > > > > > Nit, you forgot a copyright line here :) > > > > > > I can add one, but none of the other drivers in this directory has one. > > > > I think the copyright owner of this file will appreciate that. In fact, > > I think it might be required by them :) > > I think you're right. Probably just an oversight from the original. > > > > > Anyway, other than the copyright, this looks good to me. > > > > > > > > Although we should get the "validate the data" rust patch set in here > > > > soon, so we don't have to go and fix up all users of the miscdev rust > > > > api at once. Maybe I'll dig that series up over the holiday break if > > > > someone doesn't beat me to it. > > > > > > What needs doing? Do you have a link? > > > > https://lore.kernel.org/r/20240925205244.873020-1-benno.lossin@proton.me > > > > But in thinking about it more, this isn't going to work well with misc > > devices as the data is coming from userspace, which already goes through > > the user slice code. Unless userslice should be marking the data as > > untrusted? I think that needs to happen as well. > > Not too relevant here I think. The data coming in is just a single int > that is used as-is rather than any kind of index into memory. For now, yes. But in reality, the data is "untrusted" as userspace provided it, and for a sample, we should at least document that otherwise people will forget. thanks, greg k-h