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 F0F78D18139 for ; Mon, 14 Oct 2024 17:44:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6B4E96B0089; Mon, 14 Oct 2024 13:44:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 665946B008A; Mon, 14 Oct 2024 13:44:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 52CFA6B008C; Mon, 14 Oct 2024 13:44:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 2CBF06B0089 for ; Mon, 14 Oct 2024 13:44:08 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 241C1AC20F for ; Mon, 14 Oct 2024 17:43:52 +0000 (UTC) X-FDA: 82672931166.10.39244C6 Received: from nyc.source.kernel.org (nyc.source.kernel.org [147.75.193.91]) by imf23.hostedemail.com (Postfix) with ESMTP id 0611E140015 for ; Mon, 14 Oct 2024 17:44:01 +0000 (UTC) Authentication-Results: imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="bnl/7lXS"; spf=pass (imf23.hostedemail.com: domain of ardb@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=ardb@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1728927774; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=D1cqPhbp+1G0CmNMAc5P3TJBZ1xXgLshws2tjwYtpsE=; b=EpSwhSrIiFwI2lRShlaWNYbI81IvrmPQAN5N2j8pYqXRpFDlq0WI4mOI0PaA/PKjxFAG77 0tZkKrQmyfE0ZJIX7c1sdeN6s8+5chetWGL0xHXQFfJp+kFrUeBWwAef+8O2UOjVRW+9UJ nIXPqjb7nOICfsQ2N9s1rEFFtgDULhw= ARC-Authentication-Results: i=1; imf23.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b="bnl/7lXS"; spf=pass (imf23.hostedemail.com: domain of ardb@kernel.org designates 147.75.193.91 as permitted sender) smtp.mailfrom=ardb@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1728927774; a=rsa-sha256; cv=none; b=ix8aPfts98eCKRDyl0WJdRLzU3DdZSrRt5m7741q5frnJLxloghKm5hj1w90PkTCAHiZ2Y /97itY9uCx9+TB2pRuhwsILkOOlE6RsnNRRXHfSh/zl9gfDA+FrlqxrrxodR5RAoxbitn+ 0b9Cu6REYATgGodL8RoWhlbjMPmAYv4= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by nyc.source.kernel.org (Postfix) with ESMTP id 600B9A41E59 for ; Mon, 14 Oct 2024 17:43:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EFB86C4CED0 for ; Mon, 14 Oct 2024 17:44:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1728927845; bh=NfOu+U/kGbnVFc1O3Injrm6T+UY+dKV9v07LidBjm7k=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=bnl/7lXSBDcXQSQpXizt0C0nTzew6FIKS+LWf9Kw8C1T7b7jMLq2AGO7M6+VCnWYa BLN5MzeHEdRhKJ+hOU0vuU7DDXnTvCw6jkgpSzElizuSfMQGtaoAlpb2eTBKQfM1zO bjI9dXpit6Dg6KUN9GKWOQWAgdDn9RT4/LHuu9MGzvpaknI0iye8PtNZY9SnGwHoCQ gcZE25brQur9xcws2eLd04X0/dBvOOPjEuqC7gITb+p33vqSNCr8GQbaIZbqXo04Ma PNhM+CKZ8sbKknt6PYOIVHJbUL97HEJYHKOCwKpry96aIzSLV5K4b8/08pwEdsrkvn KOP3dEYeFpnGg== Received: by mail-lj1-f179.google.com with SMTP id 38308e7fff4ca-2fac6b3c220so58173851fa.2 for ; Mon, 14 Oct 2024 10:44:04 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCXTmWw0SG51IBx2c69HOK7GJIlhMT574t//kkke3x/EEm9gmYQ3QPjUTsLnXN9ZnYaxhi5O6o8KtA==@kvack.org X-Gm-Message-State: AOJu0YyZ78B2hW7CISxy/4JE1cIhDAzNyFoZBg8AuzrSW+XNVD5scNZn G9iaQhxSygInVbSIR0gkSvPLjC8l9fI/LlR/Ed6lvp4nDJFswa2HhVYORD/Ws8SZ1DOPEkTs0Zm jKIH8DLq5K/Ownm0109PbN/fMJLQ= X-Google-Smtp-Source: AGHT+IFgjcGwGJGSHKlO7QpDso667UoXGzPxbAShbvR5h2KAmP1C+JMGI1NYIOXsoPHkJkyjCAg8rvnK4mlGkYD1FuU= X-Received: by 2002:a05:6512:6d0:b0:539:8f68:e036 with SMTP id 2adb3069b0e04-539e552184bmr4136605e87.34.1728927843338; Mon, 14 Oct 2024 10:44:03 -0700 (PDT) MIME-Version: 1.0 References: <20241014125703.2287936-4-ardb+git@google.com> In-Reply-To: From: Ard Biesheuvel Date: Mon, 14 Oct 2024 19:43:52 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 0/2] Use dot prefixes for section names To: Linus Torvalds Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Masahiro Yamada , Nathan Chancellor , Suren Baghdasaryan , Kent Overstreet , Arnd Bergmann , linux-arch@vger.kernel.org, linux-mm@kvack.org, linux-kbuild@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam03 X-Rspam-User: X-Rspamd-Queue-Id: 0611E140015 X-Stat-Signature: 8c99had19is78zbpngm69pbu7nm6e4or X-HE-Tag: 1728927841-443709 X-HE-Meta: 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 q6HpOgQa PIQJ/lqHNmVfIs07Skei2oap3xblYcbuTKcWNHNq3pN8jsUQ3IbQ4Zm7FRkoRAlpFpq2I2CcOaT7yocWipZglfGuos35ngpTwzGEKFJoBrQnwPTn4rHbWDz3vqyuSLTBRguIvOVOCWtHD0FiQf8La1rvUpIXpbw5DrkMNliTgM4EainRvlyzsYoriYUEp/cCBTRLMgCSK94pyqCcSYG0Bjn3KDTrcIGfO6H7SxLQYGUG7+u5wC+Zl6LI8Y7ZlhohiTlbwPonJ69hKchnOKc6MUIyYJjLZpgVjuNdmIZ8o8RHIBs8U137OfC3pntlexZZjmDAYEwBMI945oD23zDhGuaxxGfD+hdt7F+c8BQCqaDiWPi7mGAV8LNgTyzOFJFRyq+ZCzSRP8Tei16Rk/nzbd3tkVtbVWPWlAv6r6ujLADw474sjXrI19MgAfuKVsIejZA9W 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: List-Subscribe: List-Unsubscribe: On Mon, 14 Oct 2024 at 19:29, Linus Torvalds wrote: > > On Mon, 14 Oct 2024 at 05:57, Ard Biesheuvel wrote: > > > > Pre-existing code uses a dot prefix or double underscore to prefix ELF > > section names. strip_relocs on x86 relies on this, and other out of tree > > tools that mangle vmlinux (kexec or live patching) may rely on this as > > well. > > > > So let's not deviate from this and use a dot prefix for runtime-const > > and alloc_tags sections. > > I'm not following what the actual problem is. Yes, I see that you > report that it results in section names like ".relaalloc_tags", but > what's the actual _issue_ with that? It seems entirely harmless. > > In fact, when I was going the runtime sections, I was thinking how > convenient it was for the linker to generate the start/stop symbols > for us, and that we should perhaps *expand* on that pattern. > > So this seems a step backwards to me, with no real explanation of what > the actual problem is. > > Yes, we have (two different) pre-existing patterns, but neither > pattern seems to be an actual improvement. > We have this code in arch/x86/Makefile.postlink: quiet_cmd_strip_relocs = RSTRIP $@ cmd_strip_relocs = \ $(OBJCOPY) --remove-section='.rel.*' --remove-section='.rel__*' \ --remove-section='.rela.*' --remove-section='.rela__*' $@ Of course, that could easily be fixed, I was just being cautious in case there is other, out-of-tree tooling for live patch or kexec etc that has similar assumptions wrt section names.