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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Joe Perches <joe@perches.com>
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>,
	Masahiro Yamada <masahiroy@kernel.org>,
	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>
Subject: Re: [PATCH] compiler.h: Raise minimum version of GCC to 5.1 for arm64
Date: Fri, 15 Jan 2021 15:24:07 -0800	[thread overview]
Message-ID: <CAHk-=whrJ_3iTz+Wz2cSufxnw2+g39P=YsTGaE6M24Qg4=Ef5Q@mail.gmail.com> (raw)
In-Reply-To: <eabb211c3ba394845ec3258d86406137f4c23b33.camel@perches.com>

On Thu, Jan 14, 2021 at 4:30 PM Joe Perches <joe@perches.com> wrote:
>
> KASAN v5 instead of all the old versions
> gcc 7.1 supports fallthrough.

Considering that most people won't even enable KASAN, I think that's
not a huge reason to then force people to potentially upgrade their
compilers.

That said, I do think that it might be good to just try to standardize
on the KASAN v5 code - but that could easily be done by simply making
KASAN depend as a feature on having a newer compiler version.

So the KASAN option itself could just have something like

       depends on !CC_IS_GCC || GCC_VERSION >= 70000

in it, which would allow us to just say "only v5 need apply".

As to "fallthrough", I think it's more than enough that lots of people
build with compilers that support it, and then any warnings they see
will be fixed. No need to force upgrades - it doesn't buy kernel
developers anything.

          Linus

WARNING: multiple messages have this Message-ID (diff)
From: Linus Torvalds <torvalds@linux-foundation.org>
To: Joe Perches <joe@perches.com>
Cc: Florian Weimer <fweimer@redhat.com>,
	Arnd Bergmann <arnd@kernel.org>, Theodore Ts'o <tytso@mit.edu>,
	Will Deacon <will@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Masahiro Yamada <masahiroy@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Cc: Android Kernel" <kernel-team@android.com>,
	Ard Biesheuvel <ardb@kernel.org>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH] compiler.h: Raise minimum version of GCC to 5.1 for arm64
Date: Fri, 15 Jan 2021 15:24:07 -0800	[thread overview]
Message-ID: <CAHk-=whrJ_3iTz+Wz2cSufxnw2+g39P=YsTGaE6M24Qg4=Ef5Q@mail.gmail.com> (raw)
In-Reply-To: <eabb211c3ba394845ec3258d86406137f4c23b33.camel@perches.com>

On Thu, Jan 14, 2021 at 4:30 PM Joe Perches <joe@perches.com> wrote:
>
> KASAN v5 instead of all the old versions
> gcc 7.1 supports fallthrough.

Considering that most people won't even enable KASAN, I think that's
not a huge reason to then force people to potentially upgrade their
compilers.

That said, I do think that it might be good to just try to standardize
on the KASAN v5 code - but that could easily be done by simply making
KASAN depend as a feature on having a newer compiler version.

So the KASAN option itself could just have something like

       depends on !CC_IS_GCC || GCC_VERSION >= 70000

in it, which would allow us to just say "only v5 need apply".

As to "fallthrough", I think it's more than enough that lots of people
build with compilers that support it, and then any warnings they see
will be fixed. No need to force upgrades - it doesn't buy kernel
developers anything.

          Linus

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2021-01-15 23:25 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-12 22:48 [PATCH] compiler.h: Raise minimum version of GCC to 5.1 for arm64 Will Deacon
2021-01-12 22:48 ` Will Deacon
2021-01-12 22:57 ` Nick Desaulniers
2021-01-12 22:57   ` Nick Desaulniers
2021-01-12 23:06 ` Nathan Chancellor
2021-01-12 23:06   ` Nathan Chancellor
2021-01-13  2:14 ` Linus Torvalds
2021-01-13  2:14   ` Linus Torvalds
2021-01-13  2:35   ` Linus Torvalds
2021-01-13  2:35     ` Linus Torvalds
2021-01-13 15:02     ` Catalin Marinas
2021-01-13 15:02       ` Catalin Marinas
2021-01-13 16:07 ` Catalin Marinas
2021-01-13 16:07   ` Catalin Marinas
2021-01-13 17:57   ` Masahiro Yamada
2021-01-13 17:57     ` Masahiro Yamada
2021-01-13 18:33     ` Joe Perches
2021-01-13 18:33       ` Joe Perches
2021-01-13 19:15     ` Linus Torvalds
2021-01-13 19:15       ` Linus Torvalds
2021-01-13 21:44       ` Russell King - ARM Linux admin
2021-01-13 21:44         ` Russell King - ARM Linux admin
2021-01-13 22:08         ` Linus Torvalds
2021-01-13 22:08           ` Linus Torvalds
2021-01-14  8:18           ` Ard Biesheuvel
2021-01-14  8:18             ` Ard Biesheuvel
2021-01-14 18:43             ` Linus Torvalds
2021-01-14 18:43               ` Linus Torvalds
2021-01-14 19:51               ` Joe Perches
2021-01-14 19:51                 ` Joe Perches
2021-01-14 21:18                 ` Linus Torvalds
2021-01-14 21:18                   ` Linus Torvalds
2021-01-15  0:30                   ` Joe Perches
2021-01-15  0:30                     ` Joe Perches
2021-01-15 23:24                     ` Linus Torvalds [this message]
2021-01-15 23:24                       ` Linus Torvalds
2021-02-27  7:16               ` Masahiro Yamada
2021-02-27  7:16                 ` Masahiro Yamada

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