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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 6C272C433FE for ; Wed, 9 Dec 2020 18:48:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4131523C8D for ; Wed, 9 Dec 2020 18:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733281AbgLISrm (ORCPT ); Wed, 9 Dec 2020 13:47:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:43370 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733254AbgLISr3 (ORCPT ); Wed, 9 Dec 2020 13:47:29 -0500 Date: Wed, 9 Dec 2020 18:46:44 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607539609; bh=sUy8zuiil22aMl2/aya4Ll0+5gUQS/Rh6dRvPnqxLcE=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=Ln8pQQFlioSAMr7gY5t45IpDlGO7ZDz1ZNTK+hQZVBzLQx1z8ULe1JbEw+GktEtOg eZNky1psifTOoJY0c9pxE6xEIwWX4L9AZS1gjejXskx8JuXVyszVY4QAb/yUZHV+bw ikuSNodGLtY81zbVjPHINsdhk2fLyjn4Z7KBKzaQiLpZCNtyTMFTPQRLzXj7Dcp2k/ VMuV0YJ19VzYurr2a8HFmYkMxblpoQKrDvybJSX0NFouQyexpP1K/RvSsitatmCQIf p2fAFzlPdRQ+iT6kXqlqlD6dJ0PwblRO5LjXStqrH/vdtvhQK9OuLE/KUjaPI9QLnT joVQLNKb6IXwg== From: Will Deacon To: Catalin Marinas Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, Jan Kara , Minchan Kim , Andrew Morton , "Kirill A . Shutemov" , Linus Torvalds , Vinayak Menon , kernel-team@android.com Subject: Re: [PATCH 2/2] arm64: mm: Implement arch_wants_old_faultaround_pte() Message-ID: <20201209184643.GB8778@willie-the-truck> References: <20201209163950.8494-1-will@kernel.org> <20201209163950.8494-3-will@kernel.org> <20201209183509.GH13566@gaia> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201209183509.GH13566@gaia> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 09, 2020 at 06:35:09PM +0000, Catalin Marinas wrote: > On Wed, Dec 09, 2020 at 04:39:50PM +0000, Will Deacon wrote: > > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h > > index da250e4741bd..3424f5881390 100644 > > --- a/arch/arm64/include/asm/cpufeature.h > > +++ b/arch/arm64/include/asm/cpufeature.h > > @@ -764,6 +764,18 @@ static inline bool cpu_has_hw_af(void) > > ID_AA64MMFR1_HADBS_SHIFT); > > } > > > > +static inline bool system_has_hw_af(void) > > +{ > > + u64 mmfr1; > > + > > + if (!IS_ENABLED(CONFIG_ARM64_HW_AFDBM)) > > + return false; > > + > > + mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); > > + return cpuid_feature_extract_unsigned_field(mmfr1, > > + ID_AA64MMFR1_HADBS_SHIFT); > > +} > > Could we not add a new system-wide cpu feature that checks for hardware > AF? This read_sanitised_ftr_reg() does a binary search on each > invocation. I posted a diff [1] which would allow removing the binary search for cases where we can pass the register coding as a constant (like this), but honestly, it's not like we have many ID registers so I doubt it really matters in the grand scheme of things. That said, I'm spinning a v2 anyway so I can include it for comments since I haven't posted it as a proper patch before. Will [1] https://lore.kernel.org/r/20201202172727.GC29813@willie-the-truck 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,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 1F18BC433FE for ; Wed, 9 Dec 2020 18:48:14 +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 C692723C44 for ; Wed, 9 Dec 2020 18:48:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C692723C44 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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=lDJDztW9GO2nbHqLacYGC1DcpFGyyHJL4T8JeJfzcGE=; b=wt0v9Ikdtqh1x5H6p0BqVAb/F 2aWBhtpdbNcwYVw83LRT83U75FA2q7ltj/iU1iQHZJCVMB4+SbZtUbCERFf/rZIqgmKqGPs8ZT23N FNPKTMHqVV8zsLU0BpyruoLV3FhGpV9g74z3iCLSwlieV66u2+OIHLmjlCgEMTJSzfyorBtB2wNiO Sp4rg01v9Xcsxi94C5tL7fT3QkACOuraMjKxha4ovYRI1a0TTMUkG1MqWopzWqSK+dc4QoYvjc7b8 6jpIyPuiMfmPiHfSdw1SibwnAt8Ib7Eiijdlp54HKbbXBcqdhPIFdJakKn8iqjY4DuAmR3wrCMqsC am0RSZX9w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kn4UH-000082-F9; Wed, 09 Dec 2020 18:46:53 +0000 Received: from mail.kernel.org ([198.145.29.99]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kn4UD-000065-Um for linux-arm-kernel@lists.infradead.org; Wed, 09 Dec 2020 18:46:50 +0000 Date: Wed, 9 Dec 2020 18:46:44 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1607539609; bh=sUy8zuiil22aMl2/aya4Ll0+5gUQS/Rh6dRvPnqxLcE=; h=From:To:Cc:Subject:References:In-Reply-To:From; b=Ln8pQQFlioSAMr7gY5t45IpDlGO7ZDz1ZNTK+hQZVBzLQx1z8ULe1JbEw+GktEtOg eZNky1psifTOoJY0c9pxE6xEIwWX4L9AZS1gjejXskx8JuXVyszVY4QAb/yUZHV+bw ikuSNodGLtY81zbVjPHINsdhk2fLyjn4Z7KBKzaQiLpZCNtyTMFTPQRLzXj7Dcp2k/ VMuV0YJ19VzYurr2a8HFmYkMxblpoQKrDvybJSX0NFouQyexpP1K/RvSsitatmCQIf p2fAFzlPdRQ+iT6kXqlqlD6dJ0PwblRO5LjXStqrH/vdtvhQK9OuLE/KUjaPI9QLnT joVQLNKb6IXwg== From: Will Deacon To: Catalin Marinas Subject: Re: [PATCH 2/2] arm64: mm: Implement arch_wants_old_faultaround_pte() Message-ID: <20201209184643.GB8778@willie-the-truck> References: <20201209163950.8494-1-will@kernel.org> <20201209163950.8494-3-will@kernel.org> <20201209183509.GH13566@gaia> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20201209183509.GH13566@gaia> 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-20201209_134650_077362_CCDA8834 X-CRM114-Status: GOOD ( 15.26 ) 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: Jan Kara , Minchan Kim , kernel-team@android.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Vinayak Menon , "Kirill A . Shutemov" , Andrew Morton , Linus Torvalds , 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 Wed, Dec 09, 2020 at 06:35:09PM +0000, Catalin Marinas wrote: > On Wed, Dec 09, 2020 at 04:39:50PM +0000, Will Deacon wrote: > > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h > > index da250e4741bd..3424f5881390 100644 > > --- a/arch/arm64/include/asm/cpufeature.h > > +++ b/arch/arm64/include/asm/cpufeature.h > > @@ -764,6 +764,18 @@ static inline bool cpu_has_hw_af(void) > > ID_AA64MMFR1_HADBS_SHIFT); > > } > > > > +static inline bool system_has_hw_af(void) > > +{ > > + u64 mmfr1; > > + > > + if (!IS_ENABLED(CONFIG_ARM64_HW_AFDBM)) > > + return false; > > + > > + mmfr1 = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1); > > + return cpuid_feature_extract_unsigned_field(mmfr1, > > + ID_AA64MMFR1_HADBS_SHIFT); > > +} > > Could we not add a new system-wide cpu feature that checks for hardware > AF? This read_sanitised_ftr_reg() does a binary search on each > invocation. I posted a diff [1] which would allow removing the binary search for cases where we can pass the register coding as a constant (like this), but honestly, it's not like we have many ID registers so I doubt it really matters in the grand scheme of things. That said, I'm spinning a v2 anyway so I can include it for comments since I haven't posted it as a proper patch before. Will [1] https://lore.kernel.org/r/20201202172727.GC29813@willie-the-truck _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel