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=-8.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 6666DC5ACD6 for ; Tue, 17 Mar 2020 22:34:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 310FF2073E for ; Tue, 17 Mar 2020 22:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584484480; bh=/LP+yOTLJ8bmG3iy62G9dpLGOzZo7YWw9GhpuzL/3Zs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=CrDeArmUYtKXXqA5rFN4WKnu5lNZ9f5udeMdXpxBgr9WaHvlDHbHca8Jz8h2PV9MI rSnsEhiUTcWeXMt/j3J2E15BXa0BDRunlRXoPYBhQcSULltgByy/qBbh+HWvjvSm3t uzvyfG3gBZi3wBUE+x7gAqs+YJyiScaH77w08Cxs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727064AbgCQWej (ORCPT ); Tue, 17 Mar 2020 18:34:39 -0400 Received: from mail.kernel.org ([198.145.29.99]:39544 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726476AbgCQWei (ORCPT ); Tue, 17 Mar 2020 18:34:38 -0400 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id F1DE820674; Tue, 17 Mar 2020 22:34:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584484478; bh=/LP+yOTLJ8bmG3iy62G9dpLGOzZo7YWw9GhpuzL/3Zs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ovh3ufRqT9Kuyo9vQDhUv7CQkINb8MM9jyYJfqQwQ+2OZ535SCMb8SWLt3EXfRA+E MvWraLAlFagDJiHV+WH16RTeK3bAk57Ro2Rb2j5ay4/vfaC+i1DYK8vvt/OlezHboy nvKpIex7HtHVlPKF2eU7nHym/Y/cbkuYjzF1oZ3I= Date: Tue, 17 Mar 2020 22:34:33 +0000 From: Will Deacon To: =?iso-8859-1?Q?R=E9mi?= Denis-Courmont Cc: catalin.marinas@arm.com, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] arm64: reduce trampoline data alignment Message-ID: <20200317223433.GL20788@willie-the-truck> References: <20200316124046.103844-3-remi@remlab.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200316124046.103844-3-remi@remlab.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 16, 2020 at 02:40:46PM +0200, Rémi Denis-Courmont wrote: > From: Rémi Denis-Courmont > > The trampoline data, currently consisting of two relocated pointers, > must be within a single page. However, there are no needs for it to > start a page. > > This reduces the alignment to 16 bytes (with SDEI) or 8 bytes (without > SDEI), which is sufficient to ensure that the data is entirely within a > single page of the fixmap. > > Signed-off-by: Rémi Denis-Courmont > --- > arch/arm64/kernel/entry.S | 4 ++-- > arch/arm64/mm/mmu.c | 5 ++--- > 2 files changed, 4 insertions(+), 5 deletions(-) > > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > index af17fcb4aaea..b648f9fe1e33 100644 > --- a/arch/arm64/kernel/entry.S > +++ b/arch/arm64/kernel/entry.S > @@ -858,12 +858,12 @@ SYM_CODE_END(tramp_exit_compat) > .popsection // .entry.tramp.text > #ifdef CONFIG_RANDOMIZE_BASE > .pushsection ".rodata", "a" > - .align PAGE_SHIFT > #ifdef CONFIG_ARM_SDE_INTERFACE > + .align 4 // all .rodata must be in a single fixmap page > SYM_DATA_START(__sdei_asm_trampoline_next_handler) > .quad __sdei_asm_handler > SYM_DATA_END(__sdei_asm_trampoline_next_handler) > -#endif > +#endif /* CONFIG_ARM_SDE_INTERFACE */ > SYM_DATA_START(__entry_tramp_data_start) > .quad vectors > SYM_DATA_END(__entry_tramp_data_start) > diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c > index 9b08f7c7e6f0..6a0e75f48e7b 100644 > --- a/arch/arm64/mm/mmu.c > +++ b/arch/arm64/mm/mmu.c > @@ -599,9 +599,8 @@ static int __init map_entry_trampoline(void) > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE)) { > extern char __entry_tramp_data_start[]; > > - __set_fixmap(FIX_ENTRY_TRAMP_DATA, > - __pa_symbol(__entry_tramp_data_start), > - PAGE_KERNEL_RO); > + pa_start = __pa_symbol(__entry_tramp_data_start) & PAGE_MASK; > + __set_fixmap(FIX_ENTRY_TRAMP_DATA, pa_start, PAGE_KERNEL_RO); > } > > return 0; Acked-by: Will Deacon Will