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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,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 C2AB5C4727C for ; Wed, 30 Sep 2020 17:14:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8357F207FB for ; Wed, 30 Sep 2020 17:14:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731375AbgI3ROL (ORCPT ); Wed, 30 Sep 2020 13:14:11 -0400 Received: from mail.kernel.org ([198.145.29.99]:59732 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726540AbgI3ROI (ORCPT ); Wed, 30 Sep 2020 13:14:08 -0400 Received: from gaia (unknown [31.124.44.166]) (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 245352076B; Wed, 30 Sep 2020 17:14:06 +0000 (UTC) Date: Wed, 30 Sep 2020 18:14:04 +0100 From: Catalin Marinas To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH] arm64: mm: Make flush_tlb_fix_spurious_fault() a no-op Message-ID: <20200930171403.GA29503@gaia> References: <20200930131859.16989-1-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200930131859.16989-1-will@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 30, 2020 at 02:18:59PM +0100, Will Deacon wrote: > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index f07333e86c2f..a696a7921da4 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -218,7 +218,9 @@ int ptep_set_access_flags(struct vm_area_struct *vma, > pteval = cmpxchg_relaxed(&pte_val(*ptep), old_pteval, pteval); > } while (pteval != old_pteval); > > - flush_tlb_fix_spurious_fault(vma, address); > + /* Invalidate a stale read-only entry */ > + if (dirty) > + flush_tlb_page(vma, address); > return 1; In my proposal I had a pte_accessible(pte) check instead of dirty here since we may go for an old pte directly to a writable one and a TLBI wouldn't be needed. Not that it matters from a performance perspective. Either way, Reviewed-by: Catalin Marinas