From: Peter Zijlstra <peterz@infradead.org>
To: Mark Rutland <mark.rutland@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
gcc@gcc.gnu.org, catalin.marinas@arm.com, will@kernel.org,
marcan@marcan.st, maz@kernel.org, szabolcs.nagy@arm.com,
f.fainelli@gmail.com, opendmb@gmail.com,
Andrew Pinski <pinskia@gmail.com>,
Ard Biesheuvel <ardb@kernel.org>,
x86@kernel.org, andrew.cooper3@citrix.com,
Jeremy Linton <jeremy.linton@arm.com>
Subject: Re: GCC 12 miscompilation of volatile asm (was: Re: [PATCH] arm64/io: Remind compiler that there is a memory side effect)
Date: Tue, 5 Apr 2022 16:05:22 +0200 [thread overview]
Message-ID: <YkxMov3qpHxFa/n3@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <Ykw7UnlTnx63z/Ca@FVFF77S0Q05N>
On Tue, Apr 05, 2022 at 01:51:30PM +0100, Mark Rutland wrote:
> Hi all,
>
> [adding kernel folk who work on asm stuff]
>
> As a heads-up, GCC 12 (not yet released) appears to erroneously optimize away
> calls to functions with volatile asm. Szabolcs has raised an issue on the GCC
> bugzilla:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105160
>
> ... which is a P1 release blocker, and is currently being investigated.
>
> Jemery originally reported this as an issue with {readl,writel}_relaxed(), but
> the underlying problem doesn't have anything to do with those specifically.
>
> I'm dumping a bunch of info here largely for posterity / archival, and to find
> out who (from the kernel side) is willing and able to test proposed compiler
> fixes, once those are available.
>
> I'm happy to do so for aarch64; Peter, I assume you'd be happy to look at the
> x86 side?
Sure..
next prev parent reply other threads:[~2022-04-05 14:05 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-01 16:44 [PATCH] arm64/io: Remind compiler that there is a memory side effect Jeremy Linton
2022-04-01 17:22 ` Mark Rutland
2022-04-03 7:36 ` Andrew Pinski
2022-04-03 7:47 ` Ard Biesheuvel
2022-04-03 7:47 ` Ard Biesheuvel
2022-04-04 9:14 ` Will Deacon
2022-04-03 17:40 ` Doug Berger
2022-04-05 12:51 ` GCC 12 miscompilation of volatile asm (was: Re: [PATCH] arm64/io: Remind compiler that there is a memory side effect) Mark Rutland
2022-04-05 13:04 ` Mark Rutland
2022-04-05 13:20 ` Andrew Cooper
2022-04-05 14:05 ` Peter Zijlstra [this message]
2022-04-11 10:22 ` Mark Rutland
2022-04-11 10:31 ` Mark Rutland
2022-04-11 19:02 ` Jeremy Linton
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