linux-kernel - Re: [PATCH] rust: io: use const generics for read/write offsets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-Id: <DCX6M3BCXV2W.37USDZEDRVA2G@kernel.org>
Date: Sat, 20 Sep 2025 01:56:27 +0200
From: "Danilo Krummrich" <dakr@...nel.org>
To: "Gary Guo" <gary@...yguo.net>
Cc: "Joel Fernandes" <joelagnelf@...dia.com>, "Alice Ryhl"
 <aliceryhl@...gle.com>, "Maarten Lankhorst"
 <maarten.lankhorst@...ux.intel.com>, "Maxime Ripard" <mripard@...nel.org>,
 "Thomas Zimmermann" <tzimmermann@...e.de>, "David Airlie"
 <airlied@...il.com>, "Simona Vetter" <simona@...ll.ch>, "Greg
 Kroah-Hartman" <gregkh@...uxfoundation.org>, "Rafael J. Wysocki"
 <rafael@...nel.org>, "Miguel Ojeda" <ojeda@...nel.org>, "Boqun Feng"
 <boqun.feng@...il.com>, Björn Roy Baron
 <bjorn3_gh@...tonmail.com>, "Benno Lossin" <lossin@...nel.org>, "Andreas
 Hindborg" <a.hindborg@...nel.org>, "Trevor Gross" <tmgross@...ch.edu>,
 "Bjorn Helgaas" <bhelgaas@...gle.com>,
 Krzysztof Wilczyński <kwilczynski@...nel.org>,
 <linux-kernel@...r.kernel.org>, <rust-for-linux@...r.kernel.org>,
 <dri-devel@...ts.freedesktop.org>, <linux-pci@...r.kernel.org>
Subject: Re: [PATCH] rust: io: use const generics for read/write offsets

On Fri Sep 19, 2025 at 10:56 PM CEST, Gary Guo wrote:
> Turbofish is cumbersome to write with just magic numbers, and the
> fact `{}` is needed to pass in constant expressions made this much
> worse. If the drivers try hard to avoid magic numbers, you would
> effective require  all code to be `::<{ ... }>()` and this is ugly.

In the absolute majority of cases users won't see any of that anyways, since
they'll use the register!() macro generated types.

   // Master Control Register (MCR)
   //
   // Stores the offset as associated constant.
   let mcr = regs::MCR::default();

   // Set the enabled bit.
   mcr.enable();

   // Write the data on the bus.
   //
   // Calls `io.write<Self::OFFSET>(self.data())` internally.
   mcr.write(&io);

For indexed registers it is indeed a problem though.