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From:   Richard Weinberger <richard@nod.at>
To:     Borislav Petkov <bp@alien8.de>
Cc:     Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
        Matthew Wilcox <willy@infradead.org>,
        Jann Horn <jannh@google.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Thomas Gleixner <tglx@linutronix.de>,
        kernel list <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org,
        the arch/x86 maintainers <x86@kernel.org>,
        Linux API <linux-api@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>
Subject: Re: [PATCH] x86: Deprecate a.out support
Date:   Tue, 05 Mar 2019 16:17:35 +0100
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In-Reply-To: <20190305145717.GD8256@zn.tnic>
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Am Dienstag, 5. M?rz 2019, 15:59:52 CET schrieb Borislav Petkov:
> + akpm and Linus.
> 
> On Tue, Mar 05, 2019 at 01:43:47PM +0000, Alan Cox wrote:
> > > It's been 25 years since Linux added support for ELF.  Can we just
> > > delete the a.out support entirely now?  According to the Linux-ELF HOWTO,
> > > support was added in 1.1.52 (August 1994).  It's pretty much necromancy
> > > at this point.
> > 
> > In the unlikely event that someone actually has an a.out binary they
> > can't live with they can also just write an a.out loader as an ELF
> > program entirely in userspace.
> > 
> > I'd vote for giving it the boot unless there are any architectures that
> > kept using a.out far longer due to tool chain issues ?
> 
> We can at least deprecate it on x86...
> 
> ---
> From: Borislav Petkov <bp@suse.de>
> Date: Tue, 5 Mar 2019 15:47:51 +0100
> Subject: [PATCH] x86: Deprecate a.out support
> 
> Linux supports ELF binaries for ~25 years now. a.out coredumping has
> bitrotten quite significantly and would need some fixing to get it into
> shape again but considering how even the toolchains cannot create a.out
> executables in its default configuration, let's deprecate a.out support
> and remove it a couple of releases later, instead.
> 
> Signed-off-by: Borislav Petkov <bp@suse.de>
> Cc: Al Viro <viro@zeniv.linux.org.uk>
> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
> Cc: Jann Horn <jannh@google.com>
> Cc: <linux-api@vger.kernel.org>
> Cc: <linux-fsdevel@vger.kernel.org>
> Cc: lkml <linux-kernel@vger.kernel.org>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: <x86@kernel.org>
> ---
>  arch/x86/Kconfig    | 2 +-
>  arch/x86/um/Kconfig | 1 -
>  2 files changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
> index 68261430fe6e..ade12ec4224b 100644
> --- a/arch/x86/Kconfig
> +++ b/arch/x86/Kconfig
> @@ -14,7 +14,6 @@ config X86_32
>  	select ARCH_WANT_IPC_PARSE_VERSION
>  	select CLKSRC_I8253
>  	select CLONE_BACKWARDS
> -	select HAVE_AOUT
>  	select HAVE_GENERIC_DMA_COHERENT
>  	select MODULES_USE_ELF_REL
>  	select OLD_SIGACTION
> @@ -2843,6 +2842,7 @@ config IA32_EMULATION
>  config IA32_AOUT
>  	tristate "IA32 a.out support"
>  	depends on IA32_EMULATION
> +	depends on BROKEN
>  	---help---
>  	  Support old a.out binaries in the 32bit emulation.
>  
> diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
> index f518b4744ff8..494eeb51e4e1 100644
> --- a/arch/x86/um/Kconfig
> +++ b/arch/x86/um/Kconfig
> @@ -16,7 +16,6 @@ config 64BIT
>  
>  config X86_32
>  	def_bool !64BIT
> -	select HAVE_AOUT
>  	select ARCH_WANT_IPC_PARSE_VERSION
>  	select MODULES_USE_ELF_REL
>  	select CLONE_BACKWARDS
> 

For UML,

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard