From: Cyrill Gorcunov <gorcunov@gmail.com>
To: "Thomas Weißschuh" <linux@weissschuh.net>
Cc: LKML <linux-kernel@vger.kernel.org>,
Anna-Maria Behnsen <anna-maria@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] posix-clock: drop code duplication using compat_ptr_ioctl
Date: Tue, 21 Jan 2025 21:16:14 +0300 [thread overview]
Message-ID: <Z4_kbrqCQamjSYVQ@grain> (raw)
In-Reply-To: <bb07ee50-a686-420e-abe8-0fce852086a1@t-8ch.de>
On Tue, Jan 21, 2025 at 01:48:23PM +0100, Thomas Weißschuh wrote:
...
> > Yeah, and the PTP_ENABLE_PPS/PTP_ENABLE_PPS2 consider `arg` as 0/1 flip-flop
> > so compat_ptr won't screw it. So I personally would rather stick with a more
> > simple code (taking into account that ptp is the only real underlied device
> > so far sitting in code for so long).
>
> It is valid to pass any value to these ioctls, not only booleans.
> On s390 the value 0x80000000 aka BIT(31) would interpreted as "true" by
> a native 32bit kernel and "false" by a 64bit kernel in compat mode.
Heh, indeed, I managed to forget that s390 clears the top bit and been scratching
my head thinking of how losing the sign bit is possible)
>
> It's indeed an edge case.
> Personally I prefer the correct solution.
The correct solution is better, without a doubt. Thanks for looking into the
patch, Thomas!
prev parent reply other threads:[~2025-01-21 18:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-20 22:10 [PATCH] posix-clock: drop code duplication using compat_ptr_ioctl Cyrill Gorcunov
2025-01-20 22:22 ` Thomas Weißschuh
2025-01-20 22:30 ` Cyrill Gorcunov
2025-01-20 22:41 ` Thomas Weißschuh
2025-01-21 6:48 ` Cyrill Gorcunov
2025-01-21 12:48 ` Thomas Weißschuh
2025-01-21 18:16 ` Cyrill Gorcunov [this message]
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