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=-10.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 0B6F2C433E0 for ; Tue, 16 Mar 2021 16:29:41 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 9674C650AD for ; Tue, 16 Mar 2021 16:29:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9674C650AD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com 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=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc: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=5/OmoYIZkf5//WPwSENLy/N/ys+tqa06VrEnM3rcmDk=; b=M0iCJUhWyLw/kUBQLrEK3M3A/ sbtrs9kuXI+SW/WQ09vYkyrhlUkIjeGKbRk0hBLzKhr4Ca70808eF8s+YScffVY99Wq8CITCy0f/b PgS2K7gwxKL4fDnOXZNsfb8HQkJqs4hzbU4shjm9cNWrFAxBb4LV1i7X4kST/mtGgZjQ/z8yXoPV+ SSF8e+tj7JEDTDyIaC3TKQDDtl5Hjm+KkDeuddonymZA1yKfohmR3WK7jYZsys2rqY/zo6mYAC9hU J6e2pPYRjCqOH03Vh45rJCfZeHORICAqIC/9HkiYwdTwZEeVdRiB7HmOdxNZuXWsiO67XxO1lNJbE h/3au+mmQ==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lMCY4-001EgT-HM; Tue, 16 Mar 2021 16:28:03 +0000 Received: from mail.kernel.org ([198.145.29.99]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lMCXx-001Efk-0F for linux-arm-kernel@lists.infradead.org; Tue, 16 Mar 2021 16:27:55 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 43B0B6508E; Tue, 16 Mar 2021 16:27:48 +0000 (UTC) Date: Tue, 16 Mar 2021 16:27:45 +0000 From: Catalin Marinas To: Fangrui Song Cc: Kees Cook , Arnd Bergmann , Will Deacon , Arnd Bergmann , Ard Biesheuvel , Mark Rutland , Marc Zyngier , David Brazdil , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: vmlinux.lds.S: keep .entry.tramp.text section Message-ID: <20210316162745.GA20565@arm.com> References: <20210226140352.3477860-1-arnd@kernel.org> <202102261256.AF256702@keescook> <20210227043257.k3aernmnzsvitp7c@google.com> <20210316104530.GA7309@arm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210316104530.GA7309@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210316_162753_304751_1232F1BF X-CRM114-Status: GOOD ( 17.50 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Tue, Mar 16, 2021 at 10:45:32AM +0000, Catalin Marinas wrote: > On Fri, Feb 26, 2021 at 08:32:57PM -0800, Fangrui Song wrote: > > On 2021-02-26, Kees Cook wrote: > > > On Fri, Feb 26, 2021 at 03:03:39PM +0100, Arnd Bergmann wrote: > > > > From: Arnd Bergmann > > > > > > > > When building with CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, > > > > I sometimes see an assertion > > > > > > > > ld.lld: error: Entry trampoline text too big > > > > > > Heh, "too big" seems a weird report for having it discarded. :) > > > > > > Any idea on this Fangrui? > > > > > > ( I see this is https://github.com/ClangBuiltLinux/linux/issues/1311 ) > > > > This diagnostic is from an ASSERT in arch/arm64/kernel/vmlinux.lds > > > > ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == (1 << 16), > > "Entry trampoline text too big") > > Can we not change the ASSERT to be <= PAGE_SIZE instead? Ah, that won't work as I suspect we still need the trampoline section. Arnd, do you know why this section disappears? I did a simple test with defconfig + LD_DEAD_CODE_DATA_ELIMINATION and the trampoline section is still around. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel