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From:   Masahiro Yamada <masahiroy@kernel.org>
Date:   Sat, 27 Feb 2021 16:16:14 +0900
Message-ID: <CAK7LNASOjqvp12jaXYJm=s7mO3TQy1skb10+sHRkjY63-4fk-w@mail.gmail.com>
Subject: Re: [PATCH] compiler.h: Raise minimum version of GCC to 5.1 for arm64
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Ard Biesheuvel <ardb@kernel.org>,
        Russell King - ARM Linux admin <linux@armlinux.org.uk>,
        Florian Weimer <fweimer@redhat.com>,
        Arnd Bergmann <arnd@kernel.org>,
        "Cc: Android Kernel" <kernel-team@android.com>,
        "Theodore Ts'o" <tytso@mit.edu>,
        Peter Zijlstra <peterz@infradead.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Will Deacon <will@kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
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Hi Linus,


On Fri, Jan 15, 2021 at 3:43 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> On Thu, Jan 14, 2021 at 12:18 AM Ard Biesheuvel <ardb@kernel.org> wrote:
> >
> > So if the arguments are piling up, what is holding us back, other than
> > inertia?
>
> I think we can most certainly just try increasing the minimum version
> to 5.1 in the next merge window and see.


Just a friendly reminder.

It will be nice to increase the minimum GCC version
to GCC 5.x globally.

Now, the version check has been moved to
scripts/cc-version.sh, which is invoked from
Kconfig.

If you decide to do this, please update
'gcc_min_version' in that file.


I'd like to suggest GCC 5.2 instead of 5.1
so that we can drop the following line
from arch/powerpc/Kconfig.

if GCC_VERSION >= 50200   # plugin support on gcc <= 5.1 is buggy on PPC


> > Note that banning 4.9 for arm64 and banning it in general should be
> > two different changes in any case, as the former will need to be
> > backported to -stable kernels as well.
>
> Yes. The arm64 issue is a clear and known bug, plus I suspect gcc-4.9
> is ridiculously old in the arm64 ecosystem anyway.
>
> So the arm64 issue is a bug-fix, the follow-up of just upgrading gcc
> requirements in general would be a "keep up with the times, and allow
> those variable declarations in loops".
>
>             Linus


-- 
Best Regards
Masahiro Yamada