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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 636BEC4167B for ; Mon, 26 Dec 2022 22:02:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232307AbiLZWCY (ORCPT ); Mon, 26 Dec 2022 17:02:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229522AbiLZWCV (ORCPT ); Mon, 26 Dec 2022 17:02:21 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A6563265F; Mon, 26 Dec 2022 14:02:20 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id E3B82CE0E79; Mon, 26 Dec 2022 22:02:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1732C433EF; Mon, 26 Dec 2022 22:02:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1672092137; bh=ry6lx+uexHhl+KAnI+uFm4EaQ8KJmvU/sxNXOfCYXu0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=jsdalTDD884x4PWJj5rh7s/dUmy4mcwNC7yb8uxB7yOFTwR+SVlYpUnv9rWhbU4QM UtcPcWhnl+4bs17JHduLwRWmBk/zp9fBW4+NisAuun//upx7NJE8GCS3P1JSX6B2qI s+wc4Za+v28XorBxEVu4xqKa8oZEl30bpl35bGiOMF/h7U1mIPIYmVLlybWALoj49+ Zyd13FmdEFRGngRKL0AT85sRbazxODqx2WTz3b1lr91PpRlAt7Oo1iFanVxrUCYE/6 yHhTmViJlhlbgMBGJREvC69nIkaoINMO+qqoXlcHLHQa8CbepamcSzfBDXRsPv3axd cw2nqaCZetXEg== Date: Mon, 26 Dec 2022 22:02:11 +0000 From: Conor Dooley To: Masahiro Yamada Cc: linux-arch@vger.kernel.org, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, Ard Biesheuvel , Thorsten Leemhuis , Catalin Marinas , Will Deacon , linux-arm-kernel@lists.infradead.org, linux-riscv@lists.infradead.org, Dennis Gilmore , Albert Ou , Arnd Bergmann , Jisheng Zhang , Nicolas Schier , Palmer Dabbelt , Paul Walmsley Subject: Re: [PATCH] arch: fix broken BuildID for arm64 and riscv Message-ID: References: <20221224192751.810363-1-masahiroy@kernel.org> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="3A7DtNG3krRkXmgE" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --3A7DtNG3krRkXmgE Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hey Masahiro, On Tue, Dec 27, 2022 at 04:06:35AM +0900, Masahiro Yamada wrote: > On Mon, Dec 26, 2022 at 12:18 AM Conor Dooley wrote: > > On Sun, Dec 25, 2022 at 04:27:51AM +0900, Masahiro Yamada wrote: > > > Dennis Gilmore reports that the BuildID is missing in the arm64 vmlin= ux > > > since commit 994b7ac1697b ("arm64: remove special treatment for the > > > link order of head.o"). > > > > > > The issue is that the type of .notes section, which contains the Buil= dID, > > > changed from NOTES to PROGBITS. > > > > > > Ard Biesheuvel figured out that whichever object gets linked first ge= ts > > > to decide the type of a section, and the PROGBITS type is the result = of > > > the compiler emitting .note.GNU-stack as PROGBITS rather than NOTE. > > > > > > While Ard provided a fix for arm64, I want to fix this globally becau= se > > > the same issue is happening on riscv since commit 2348e6bf4421 ("risc= v: > > > remove special treatment for the link order of head.o"). This problem > > > will happen in general for other architectures if they start to drop > > > unneeded entries from scripts/head-object-list.txt. > > > > > > Discard .note.GNU-stack in include/asm-generic/vmlinux.lds.h. > > > > > > riscv needs to change its linker script so that DISCARDS comes before > > > the .notes section. > > > > No idea why I decided to look at patchwork today, but this seems to > > break the build on RISC-V, there's a whole load of the following in the > > output: > > `.LPFE4' referenced in section `__patchable_function_entries' of kernel= /trace/trace_selftest_dynamic.o: defined in discarded section `.text.exit' = of kernel/trace/trace_selftest_dynamic.o > > > > I assume that's what's doing it, but given the day that's in it - I > > haven't looked into this any further, nor gone and fished the logs out = of > > the builder. >=20 >=20 > arch/riscv/kernel/vmlinux.lds.S clearly says: > /* we have to discard exit text and such at runtime, not link time */ >=20 > riscv already relies on the linker not discarding EXIT_{TEXT,DATA} > so riscv should define RUNTIME_DISCARD_EXIT like x86, arm64. Huh, fair enough. The diff for that appears to be trivial, but I was not able to correctly determine a fixes tag. I may have erred in my history-diving, but it's a wee bit hard to determine the correct fixes tag. That comment about runtime discards appears to date back to commit fbe934d69eb7 ("RISC-V: Build Infrastructure") in 2017 - apparently pre-dating the addition of the define in the first place. Commit 84d5f77fc2ee ("x86, vmlinux.lds: Add RUNTIME_DISCARD_EXIT to generic DISCARDS") added it to x86 but not to arm64 - but it seems like it was added to arm during a later reword. Does that make 84d5f77fc2ee the correct one to mark it as a fix of & riscv was just overlooked when the define was added? > Anyway, I came up with a simpler patch, so I do not need to > touch around arch linker scripts. >=20 > I sent v2. > https://lore.kernel.org/lkml/20221226184537.744960-1-masahiroy@kernel.org= /T/#u Sweet, thanks. Hopefully the automation likes that version better :) --3A7DtNG3krRkXmgE Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCY6oZ4wAKCRB4tDGHoIJi 0vx8AP9KqS1+Wa8jonc1+vZRskZt+Z6ZPC4i6vIUI3Y9GBVSwgEApJRM44pmtZPa H1qE+gJ/vNyix6QqYiMlLy5OV2vFwQo= =FbKh -----END PGP SIGNATURE----- --3A7DtNG3krRkXmgE--