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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A677AC433EA for ; Mon, 29 Jun 2020 19:05:15 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7802D2053B for ; Mon, 29 Jun 2020 19:05:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="1pIRana0"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="N+rbp9GA" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7802D2053B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uKmxsxlY6NvwlVVlApgFL1lepQ6qpWSWgqMXDrHAn30=; b=1pIRana0hQtBSZ/N3sl0aT07v BnyEm8jfB/X/Q/9mf1E2sAtNoJSZy21SHt090fA1Z4cKz7f4Tq9qCU5VomrxsfcAvfRyB+Q4FPkUC LQNqlXgS2EHRNYCpiLlKlAAH2vghNh2Avf59xup5hAkQHeJyZ6ZVhEXbc5AFPSOj/9IKdl75Usbit Jlb8Qvk2N6feth3uEVCFwviCtpXkXPTxmWscSIVhjr3rTp9toP/D8JgmQB00NGVQml9vVXbcECJ9V 5sFKT3Q/W+M2j+I1kboKPrbYbqhEsfbeaDo/EsUryOfjxuVcPekyt4SjdRPBOzbt1+qFkooV9qc4f M/368tDvQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jpz3y-0004f5-17; Mon, 29 Jun 2020 19:03:30 +0000 Received: from pandora.armlinux.org.uk ([2001:4d48:ad52:32c8:5054:ff:fe00:142]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jpz3u-0004eY-Vn for linux-arm-kernel@lists.infradead.org; Mon, 29 Jun 2020 19:03:27 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=+IitMUk+eOYapugNWdcU2qNl/SJeRY/e+GCy2zsMLo8=; b=N+rbp9GAXyeaJr2JEOHz+UXKi RsSRxVTngHhTRvU12HFs410qqK0KgYvJnLV4c+gxMbCoh3lnabXdW68dUe+tiDxwUQf835ZcIukvO nP+iLDAsjH6047RD10Y8a3A+vLOoAIdwFz5UwQ2vjB/iPjCPwyjp8PTOsP1erptR/bqeZGFkElxUE YTaLVJEib0JGcCyLbw2ccxW1Y35fnPlTX4rz1m2859yaEtnKzdu6gF39mRrYiZLlsKQEKRCiINLWl z0QldW6EbOGfQyx1S0HxtBSebUfIaVLEDFaPlc4HlkrZS+WwFMrEEJcwTNdvYY2LcRWZaTe5c6mzz zvLOSXRqA==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:33208) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jpz3m-00088W-9q; Mon, 29 Jun 2020 20:03:18 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jpz3k-0007MT-Qr; Mon, 29 Jun 2020 20:03:16 +0100 Date: Mon, 29 Jun 2020 20:03:16 +0100 From: Russell King - ARM Linux admin To: Arvind Sankar Subject: Re: [PATCH v4 14/17] arm/build: Warn on orphan section placement Message-ID: <20200629190316.GY1551@shell.armlinux.org.uk> References: <20200629061840.4065483-1-keescook@chromium.org> <20200629061840.4065483-15-keescook@chromium.org> <20200629155401.GB900899@rani.riverdale.lan> <20200629180703.GX1551@shell.armlinux.org.uk> <20200629181514.GA1046442@rani.riverdale.lan> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200629181514.GA1046442@rani.riverdale.lan> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , linux-arch@vger.kernel.org, linux-efi@vger.kernel.org, Kees Cook , Arnd Bergmann , Peter Collingbourne , Catalin Marinas , Masahiro Yamada , x86@kernel.org, Nick Desaulniers , linux-kernel@vger.kernel.org, Nathan Chancellor , clang-built-linux@googlegroups.com, Ingo Molnar , James Morse , Thomas Gleixner , Borislav Petkov , Will Deacon , Ard Biesheuvel , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, Jun 29, 2020 at 02:15:14PM -0400, Arvind Sankar wrote: > On Mon, Jun 29, 2020 at 07:07:04PM +0100, Russell King - ARM Linux admin wrote: > > On Mon, Jun 29, 2020 at 11:54:01AM -0400, Arvind Sankar wrote: > > > On Sun, Jun 28, 2020 at 11:18:37PM -0700, Kees Cook wrote: > > > > We don't want to depend on the linker's orphan section placement > > > > heuristics as these can vary between linkers, and may change between > > > > versions. All sections need to be explicitly named in the linker > > > > script. > > > > > > > > Specifically, this would have made a recently fixed bug very obvious: > > > > > > > > ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup' > > > > > > > > Discard unneeded sections .iplt, .rel.iplt, .igot.plt, and .modinfo. > > > > > > > > Add missing text stub sections .vfp11_veneer and .v4_bx. > > > > > > > > Add debug sections explicitly. > > > > > > > > Finally enable orphan section warning. > > > > > > This is unrelated to this patch as such, but I noticed that ARM32/64 places > > > the .got section inside .text -- is that expected on ARM? > > > > Do you mean in general, in the kernel vmlinux, in the decompressor > > vmlinux or ... ? > > > > Sorry, in the kernel vmlinux. ARM_TEXT includes *(.got) for 32-bit, and > the 64-bit vmlinux.lds.S includes it in .text as well. The decompressor > for 32-bit keeps it separate for non-EFI stub kernel and puts it inside > .data for EFI stub. The main 32-bit kernel image doesn't use the .got - I don't think it actually even exists. The decompressor (non-EFI) uses the .got as a way of getting position independence, and that must be part of the binary image at a fixed offset from the .text section. The decompressor self-fixes up the GOT entries. In the case of the decompressor being flashed and executed from NOR flash, the decompressor must be built for the specific address(es) that it will reside (which does away with the .got table.) For EFI, it needs to be in the .data section (which is in that case always a fixed offset from .text) so that it can be written to so the fix-ups work. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last! _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel