linux-kernel - Re: [PATCH v2 2/5] rust: io: factor out MMIO read/write macros

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

Message-Id: <DDKJO7HME02Z.2HXY61JBM3GZN@kernel.org>
Date: Fri, 17 Oct 2025 13:01:46 +0200
From: "Danilo Krummrich" <dakr@...nel.org>
To: "Zhi Wang" <zhiw@...dia.com>
Cc: <rust-for-linux@...r.kernel.org>, <bhelgaas@...gle.com>,
 <kwilczynski@...nel.org>, <ojeda@...nel.org>, <alex.gaynor@...il.com>,
 <boqun.feng@...il.com>, <gary@...yguo.net>, <bjorn3_gh@...tonmail.com>,
 <lossin@...nel.org>, <a.hindborg@...nel.org>, <aliceryhl@...gle.com>,
 <tmgross@...ch.edu>, <linux-pci@...r.kernel.org>,
 <linux-kernel@...r.kernel.org>, <cjia@...dia.com>, <smitra@...dia.com>,
 <ankita@...dia.com>, <aniketa@...dia.com>, <kwankhede@...dia.com>,
 <targupta@...dia.com>, <zhiwang@...nel.org>, <acourbot@...dia.com>,
 <joelagnelf@...dia.com>, <jhubbard@...dia.com>, <markus.probst@...teo.de>
Subject: Re: [PATCH v2 2/5] rust: io: factor out MMIO read/write macros

On Thu Oct 16, 2025 at 11:02 PM CEST, Zhi Wang wrote:
> @@ -122,10 +139,9 @@ macro_rules! define_read {
>          $(#[$attr])*
>          #[inline]
>          pub fn $name(&self, offset: usize) -> $type_name {
> -            let addr = self.io_addr_assert::<$type_name>(offset);
> +            let _addr = self.io_addr_assert::<$type_name>(offset);
>  
> -            // SAFETY: By the type invariant `addr` is a valid address for MMIO operations.
> -            unsafe { bindings::$c_fn(addr as *const c_void) }
> +            $call_macro!($c_fn, self, offset, $type_name, _addr).unwrap_or(!0)

This introduces unnecessary CPU cycles in the infallible case, I think the
implementations of the try and non-try variants should remain separate.