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From: "Eric W. Biederman" <ebiederm@xmission.com>
To: Ivan Kokshaysky <ink@unseen.parts>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
	 Arnd Bergmann <arnd@arndb.de>,
	 Richard Henderson <richard.henderson@linaro.org>,
	 Matt Turner <mattst88@gmail.com>,  Kees Cook <kees@kernel.org>,
	 "Paul E. McKenney" <paulmck@kernel.org>,
	 linux-alpha@vger.kernel.org, linux-mm@kvack.org,
	 linux-kernel@vger.kernel.org,  Michael Cree <mcree@orcon.net.nz>,
	 Sam James <sam@gentoo.org>,
	 "Maciej W. Rozycki" <macro@orcam.me.uk>,
	 Geert Uytterhoeven <geert@linux-m68k.org>,
	 Michael Karcher <kernel@mkarcher.dialup.fu-berlin.de>,
	 Chris Hofstaedtler <zeha@debian.org>,
	 util-linux@vger.kernel.org, linux-mips@vger.kernel.org,
	 loongarch@lists.linux.dev
Subject: Re: [PATCH] alpha/elf: Fix misc/setarch test of util-linux by removing 32bit support
Date: Sun, 12 Jan 2025 23:32:54 -0600	[thread overview]
Message-ID: <875xmjth15.fsf@email.froward.int.ebiederm.org> (raw)
In-Reply-To: <Z4KN_aOT6uZRAm8a@minute> (Ivan Kokshaysky's message of "Sat, 11 Jan 2025 16:27:57 +0100")

Ivan Kokshaysky <ink@unseen.parts> writes:

> On Fri, Jan 10, 2025 at 06:16:28PM -0600, Eric W. Biederman wrote:
>> 
>> Richard Henderson <richard.henderson@linaro.org> writes[1]:
>> 
>> > There was a Spec benchmark (I forget which) which was memory bound and ran
>> > twice as fast with 32-bit pointers.
>> >
>> > I copied the idea from DEC to the ELF abi, but never did all the other work
>> > to allow the toolchain to take advantage.
>> >
>> > Amusingly, a later Spec changed the benchmark data sets to not fit into a
>> > 32-bit address space, specifically because of this.
>> >
>> > I expect one could delete the ELF bit and personality and no one would
>> > notice. Not even the 10 remaining Alpha users.
>> 
>> In [2] it was pointed out that parts of setarch weren't working
>> properly on alpha because it has it's own SET_PERSONALITY
>> implementation.  In the discussion that followed Richard Henderson
>> pointed out that the 32bit pointer support for alpha was never
>> completed.
>> 
>> Fix this by removing alpha's 32bit pointer support.
>> 
>> As a bit of paranoia refuse to execute any alpha binaries that hafe
>> the EF_ALPHA_32BIT flag set.  Just to fail explicitly in case someone
>> somewhere has binaries that trying to use alpha's 32bit pointer
>> support.
>
> In general I agree, but then someone ought to remove the "--taso" option
> from GNU ld, which produces such binaries.

Please feel free to write such a patch.  I don't know the GNU ld process
well enough to write that patch.

It would be good to remove dead code and confusing code from GNU ld,
as well as from the linux kernel.

Eric


  reply	other threads:[~2025-01-13  5:33 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-01-03 14:01 [PATCH] alpha: Fix personality flag propagation across an exec John Paul Adrian Glaubitz
2025-01-08 22:49 ` Kees Cook
2025-01-09  0:52   ` Jeff Xu
2025-01-09  8:01 ` Arnd Bergmann
2025-01-09  8:43   ` Arnd Bergmann
2025-01-09  8:46     ` John Paul Adrian Glaubitz
2025-01-09  8:56       ` Arnd Bergmann
2025-01-09  9:12         ` John Paul Adrian Glaubitz
2025-01-09 16:18           ` Eric W. Biederman
2025-01-09 16:52             ` Arnd Bergmann
2025-01-09 17:17               ` Eric W. Biederman
2025-01-09 20:10             ` Maciej W. Rozycki
2025-01-09 20:53               ` Arnd Bergmann
2025-01-12 14:40                 ` Maciej W. Rozycki
2025-01-10  0:28             ` Richard Henderson
2025-01-11  0:16           ` [PATCH] alpha/elf: Fix misc/setarch test of util-linux by removing 32bit support Eric W. Biederman
2025-01-11  1:17             ` Richard Henderson
2025-01-11 10:37             ` John Paul Adrian Glaubitz
2025-01-12 14:40               ` Maciej W. Rozycki
2025-01-12 14:56                 ` John Paul Adrian Glaubitz
2025-01-13  5:39                   ` [PATCH v2] " Eric W. Biederman
2025-01-18 10:35                     ` Ivan Kokshaysky
2025-01-26 17:15                       ` John Paul Adrian Glaubitz
2025-01-27 13:27                         ` Ivan Kokshaysky
2025-02-03 11:55                     ` John Paul Adrian Glaubitz
2025-02-06 15:42                     ` Kees Cook
2025-01-11 11:26             ` [PATCH] " Arnd Bergmann
2025-01-11 15:27             ` Ivan Kokshaysky
2025-01-13  5:32               ` Eric W. Biederman [this message]
2025-01-11 21:26             ` John Paul Adrian Glaubitz

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