From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id B71F0C433EF for ; Wed, 20 Apr 2022 20:04:52 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id BA2AC6B0071; Wed, 20 Apr 2022 16:04:51 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B51A46B0073; Wed, 20 Apr 2022 16:04:51 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A1A3E6B0074; Wed, 20 Apr 2022 16:04:51 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id 8E7076B0071 for ; Wed, 20 Apr 2022 16:04:51 -0400 (EDT) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 565E722089 for ; Wed, 20 Apr 2022 20:04:51 +0000 (UTC) X-FDA: 79378335582.14.BE6FD13 Received: from mout.kundenserver.de (mout.kundenserver.de [212.227.126.135]) by imf03.hostedemail.com (Postfix) with ESMTP id 1C9C820018 for ; Wed, 20 Apr 2022 20:04:48 +0000 (UTC) Received: from mail-wr1-f45.google.com ([209.85.221.45]) by mrelayeu.kundenserver.de (mreue011 [213.165.67.97]) with ESMTPSA (Nemesis) id 1MOQyE-1nXrpf1XKA-00Prty for ; Wed, 20 Apr 2022 22:04:49 +0200 Received: by mail-wr1-f45.google.com with SMTP id p18so3744794wru.5 for ; Wed, 20 Apr 2022 13:04:49 -0700 (PDT) X-Gm-Message-State: AOAM531mYjEN/F+kMWicihXd0vhllFRrONeDmkbT9gBCOpdQLhlfuQZu CMkFb+tzlKQuJbvYSfpYaxdN+JDwLkz/mNLqupE= X-Google-Smtp-Source: ABdhPJzQqXetCmaGkZ0VLDQKkxSmuQBexNxn4+LtaoO2pmxTQhac0Nj1iF3iDiepN/wJPA+ZQPYKZ600Fq7P1vAaoZE= X-Received: by 2002:adf:e106:0:b0:20a:b31b:213d with SMTP id t6-20020adfe106000000b0020ab31b213dmr2425684wrz.219.1650485088720; Wed, 20 Apr 2022 13:04:48 -0700 (PDT) MIME-Version: 1.0 References: <87levzzts4.fsf_-_@email.froward.int.ebiederm.org> <20220420165935.GA12207@brightrain.aerifal.cx> <202204201044.ACFEB0C@keescook> In-Reply-To: <202204201044.ACFEB0C@keescook> From: Arnd Bergmann Date: Wed, 20 Apr 2022 22:04:32 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] binfmt_flat: Remove shared library support To: Kees Cook Cc: Rich Felker , Palmer Dabbelt , "Eric W . Biederman" , Damien Le Moal , Niklas.Cassel@wdc.com, Al Viro , Paul Walmsley , Albert Ou , Mike Frysinger , "# 3.4.x" , Linux FS-devel Mailing List , Linux-MM , linux-riscv , linux-arch , Geert Uytterhoeven , linux-m68k , Greg Ungerer , Linux ARM , Linux-sh list , Yoshinori Sato Content-Type: text/plain; charset="UTF-8" X-Provags-ID: V03:K1:TT9fdGEeK7YsJ/zGgwEpKs7ezSRjP6sLVI1kCZd27uSV0aOc75/ kr++BOcGZHOZrH8ZUJNgUneLyo7KFymzI8EqjGxs7xB7z2vyRWEQbOzauxuY06xsVk2rbCI T7ihuXH1fmA5DNFBrh2ysZqF6f4882ZukDv7ihvpHONu/tc29myUGTETxXUcHjVlLRtkfin 2mGi4z16D/DwA++rUS8Qg== X-UI-Out-Filterresults: notjunk:1;V03:K0:zt8ZfLLz654=:Sac7XM3B8Itzb8VoDEaLJo rKzsV6N0e6bA3OEAtKrZvYh+1N2aIrkEVHlzZ5PjCIhoT0NUKZe94x1UvHBy4KNzmosruV8ju r0zhgC7gI2va87z1+cSN5d0APChP7mvm3L+TAM7JvONC9RKg8+QIVs5vWcg7v8kcLelAujItd QJerO85UAmyBZ9IJCuxfV8hAkxgiXrccAcVuNbBTYxGM3T05d9cbDKM4KJ1eywX4qpt533t1A RlwN9vXhieVYKtL+dz2uxU9OORzY9GdaVwDKKF738WzMt1IchlvOFwO5Vp15yyDYHgVqLuI30 sW1WBmXMaMz6sJVjxTZ6IumssRws+OWbrPhPh3FuYH17tzbpfTAPJROyRcfBn1zmI9RoM3NFh YMkA/RtoNqELJlJU5787DmCE23iYtEyeA7403MdwRpxnwEubO3I8VTqd1sUtLdAlu1hf/Iogl EmX3v5aMaHZl3LjuPtK0oy8hgsUSuuYFJY0XE//Juv5amw2OgSPRSyyXRL01cJvWD6dDFho+K tMTil/10Fj8vwfSiMnau73m/Bajh8dgmMCDyvSM3iRynknrVL29mT9MuLIj95y/H4uKecUcgy 3NgVTkWE+aA6tu0sG2WJpEezKkZb0nbG8UnQWV/uTjv/e2isUst0jnOl4tfpZgkJVdgOjnayU jiNoryIXqPJWSQKIolJQYltuGmdbxRCsWK0P7he9GPFOV2Jlr+6tSJkU4IRGZ2vbq5ah5SxBc lJNTutEmKSzJ03GxnZrQDxqr5sS9RqNmyRRNpp+Ino9th/9phcY5n6xeUHELW80Ead5jSg+hd Nbv2NrB/a1TEtFzMKyaM4RHZDRhBJjfahdcupQHwHJ0t4Y0Yr4= X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 1C9C820018 X-Stat-Signature: w4yaem38bt7ckz37huthxddca3m6y86c Authentication-Results: imf03.hostedemail.com; dkim=none; spf=none (imf03.hostedemail.com: domain of arnd@arndb.de has no SPF policy when checking 212.227.126.135) smtp.mailfrom=arnd@arndb.de; dmarc=none X-HE-Tag: 1650485088-517720 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Apr 20, 2022 at 7:47 PM Kees Cook wrote: > > Yeah, I was trying to understand why systems were using binfmt_flat and > not binfmt_elf, given the mention of elf2flat -- is there really such a > large kernel memory footprint savings to be had from removing > binfmt_elf? I think the main reason for using flat binaries is nommu support on m68k, xtensa and risc-v. The regular binfmt_elf support requires an MMU, and the elf-fdpic variant is only available for arm and sh at this point (the other nommu architectures got removed over time). Arnd