linux-kernel - Re: [PATCH] drm/panthor: Convert IOCTL defines to an enum

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: <CAL_JsqK_6ttLT-u-BzgOrCg=GWtNi4OP_Zw8iivXqKQ=t_ZA3Q@mail.gmail.com>
Date: Wed, 5 Feb 2025 10:43:02 -0600
From: Rob Herring <robh@...nel.org>
To: Erik Faye-Lund <erik.faye-lund@...labora.com>
Cc: Boris Brezillon <boris.brezillon@...labora.com>, Steven Price <steven.price@....com>, 
	Liviu Dudau <liviu.dudau@....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>, Miguel Ojeda <ojeda@...nel.org>, 
	Alex Gaynor <alex.gaynor@...il.com>, Boqun Feng <boqun.feng@...il.com>, 
	Gary Guo <gary@...yguo.net>, Björn Roy Baron <bjorn3_gh@...tonmail.com>, 
	Benno Lossin <benno.lossin@...ton.me>, Andreas Hindborg <a.hindborg@...nel.org>, 
	Alice Ryhl <aliceryhl@...gle.com>, Trevor Gross <tmgross@...ch.edu>, 
	Beata Michalska <beata.michalska@....com>, dri-devel@...ts.freedesktop.org, 
	linux-kernel@...r.kernel.org, rust-for-linux@...r.kernel.org
Subject: Re: [PATCH] drm/panthor: Convert IOCTL defines to an enum

On Wed, Feb 5, 2025 at 8:17 AM Erik Faye-Lund
<erik.faye-lund@...labora.com> wrote:
>
> On Wed, 2025-02-05 at 11:53 +0100, Erik Faye-Lund wrote:
> > On Tue, 2025-02-04 at 17:28 -0600, Rob Herring (Arm) wrote:
> > > Use an enum instead of #defines for panthor IOCTLs. This allows the
> > > header to be used with Rust code as bindgen can't handle complex
> > > defines.
> > >
> >
> >
> > Unfortunately, this goes in the opposite direction than what I was
> > asked to do here:
> >
> > https://lore.kernel.org/dri-devel/20241029140125.0607c26f@collabora.com/
> >
> > ...I still intend to get around to doing that, because we have
> > problems
> > with C enum and large values. I don't know if we can solve that while
> > making Rust happy without requiring C23 (which allows to specify the
> > underlying type of an enum), unfortunately...
> >
>
> Seems I misunderstood Boris, and he was referring to flags. The enums
> are of course fine to make into real enums.

Maybe we're relying on compiler specific behavior, but that's nothing
new in the kernel. This worked fine for me with both gcc and clang:

#include <stdio.h>

enum foo {
        BAR = (1UL << 63),
};

int main(void)
{
        printf("%lx\n", BAR);
        return 0;
}

Rob