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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B2B0CECAAA3 for ; Fri, 26 Aug 2022 06:45:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:CC:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=SSQp+CBlDc8lHAxW978mzbEM8GFUO82t1AMlgtCfOqQ=; b=XnYPnK0e7+/2EQ ROYcOpt1vWpV0l7eQZDgWwBZTR7Y2PqsskUECEuXEIwDw/mQWQBPjgufP6dAhIGDlDIiNQz0Jet49 l3ZvDgcboUxP2FFP3z/FuF2rH+ZbrTZwwLq13ICXKGW0aXzP9xogmP3HpTLFE8WD99R3eFKSqIDzM BpxZj7VsB/Jp8plnkrv6BvzTCxt0kQhFE8UGQchL8h3uikFi4DVLuq1QgLFmuo2it5n17zfVIui8P 4RtYJTBf6WyCkL34+hoNoy1HeuJ6OoZt67y2tYhl1ISgaaXD0oQBNQSabO998seyzu2n/w6aOmFLU JxfKlowPmaihB7OJ5v+A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oRT5Q-00EqZi-Ca; Fri, 26 Aug 2022 06:45:00 +0000 Received: from szxga02-in.huawei.com ([45.249.212.188]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oRT5M-00EqXv-7k for linux-riscv@lists.infradead.org; Fri, 26 Aug 2022 06:44:58 +0000 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MDVZk42sGzYcpx; Fri, 26 Aug 2022 14:40:30 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 26 Aug 2022 14:44:49 +0800 Received: from [10.174.179.234] (10.174.179.234) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 26 Aug 2022 14:44:48 +0800 Message-ID: <7718a9bc-e976-daeb-f490-e7b5190e50b6@huawei.com> Date: Fri, 26 Aug 2022 14:44:48 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH -next v2 2/2] riscv: extable: add new extable type EX_TYPE_KACCESS_ERR_ZERO support To: Andrew Jones CC: Paul Walmsley , Palmer Dabbelt , Palmer Dabbelt , Albert Ou , , , , , Guohanjun References: <20220815032025.2685516-1-tongtiangen@huawei.com> <20220815032025.2685516-3-tongtiangen@huawei.com> <20220825110602.bog5mjpascvikwxx@kamzik> From: Tong Tiangen In-Reply-To: <20220825110602.bog5mjpascvikwxx@kamzik> X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220825_234456_476198_F4ACAA7B X-CRM114-Status: UNSURE ( 9.65 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: base64 Content-Type: text/plain; charset="utf-8"; Format="flowed" Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org CgrlnKggMjAyMi84LzI1IDE5OjA2LCBBbmRyZXcgSm9uZXMg5YaZ6YGTOgo+IE9uIE1vbiwgQXVn IDE1LCAyMDIyIGF0IDAzOjIwOjI1QU0gKzAwMDAsIFRvbmcgVGlhbmdlbiB3cm90ZToKPj4gQ3Vy cmVudGx5LCBUaGUgZXh0YWJsZSB0eXBlIEVYX1RZUEVfVUFDQ0VTU19FUlJfWkVSTyBpcyB1c2Vk IGJ5Cj4+IF9fZ2V0L3B1dF9rZXJuZWxfbm9mYXVsdCgpLCBidXQgdGhvc2UgaGVscGVycyBhcmUg bm90IHVhY2Nlc3MgdHlwZSwgc28gd2UKPj4gYWRkIGEgbmV3IGV4dGFibGUgdHlwZSBFWF9UWVBF X0tBQ0NFU1NfRVJSX1pFUk8gd2hpY2ggY2FuIGJlIHVzZWQgYnkKPj4gX19nZXQvcHV0X2tlcm5l bF9ub19mYXVsdCgpLgo+Pgo+PiBPbmx5IHJlZmFjdG9yIGNvZGUgd2l0aG91dCBhbnkgZnVuY3Rp b25hbCBjaGFuZ2VzLgo+IAo+IFRoaXMgaXNuJ3QgcXVpdGUgdHJ1ZS4gX19nZXQvcHV0X2tlcm5l bF9ub2ZhdWx0IG5vdyBzZXRzIGEgZGlmZmVyZW50Cj4gZXh0YWJsZSB0eXBlIChhcyB0aGUgY29t bWl0IG1lc3NhZ2Ugc2F5cykuIEJ1dCwgbm90aGluZyBzcGVjaWFsIHNlZW1zCj4gdG8gYmUgZG9u ZSB3aXRoIHRoYXQsIHNvIHRoZXJlJ3MgZWZmZWN0aXZlbHkgbm8gZnVuY3Rpb25hbCBjaGFuZ2Uu IENhbgo+IHlvdSBwbGVhc2UgZWxhYm9yYXRlIG9uIHRoZSBtb3RpdmF0aW9uIGZvciB0aGlzIGNo YW5nZT8gV2hlcmUgd2lsbCB0aGUKPiBLQUNDRVNTIHR5cGUgbmVlZCB0byBiZSBkaXN0aW5ndWlz aGVkIGZyb20gdGhlIFVBQ0NFU1MgdHlwZT8KClRoZSBpbnRyb2R1Y3Rpb24gb2YgRVhfVFlQRV9L QUNDRVNTX0VSUl9aRVJPIGRvZXMgbm90IGNoYW5nZSBhbnkgCmZ1bmN0aW9uLCBidXQgbWFrZXMg YSBjb3JyZWN0IGRpc3RpbmN0aW9uIGluIHRoZSBhY3R1YWwgdHlwZSwgaW5kaWNhdGluZyAKdGhh dCB0aGVyZSBhcmUgaW5kZWVkIHNvbWUga2FjY2VzcyBlbnRyaWVzIGluIGV4dGFibGUuIEkgdGhp bmsgdGhpcyAKb3B0aW1pemF0aW9uIGlzIG1vcmUgY2xlYXIgYW5kIHJlYXNvbmFibGUuCgpBIGZl dyB3ZWVrcyBhZ28sIEkgZGlkIHNvbWV0aGluZyBzaW1pbGFyIG9uIGFybTY0WzFdLiBJIHRoaW5r IHRoaXMgCm9wdGltaXphdGlvbiBjYW4gYWxzbyBiZSB1c2VkIG9uIHJpc2N2LgoKV2UgY2FuIGRv IHNvbWUgZmVhdHVyZXMgdGhhdCBhcmUgdXNlZCBvbiB1YWNjc3MgYnV0IG5vdCBhcHBsaWNhYmxl IG9uIAprYWNjZXNzIGluIHRoZSBmdXR1cmVbMl0uCgpbMV0gCmh0dHBzOi8vbG9yZS5rZXJuZWwu b3JnL2xrbWwvMjAyMjA2MjEwNzI2MzguMTI3MzU5NC0yLXRvbmd0aWFuZ2VuQGh1YXdlaS5jb20v ClsyXWh0dHBzOi8vbG9yZS5rZXJuZWwub3JnL2xrbWwvMjAyMjA4MTIwNzA1NTcuMTAyODQ5OS00 LXRvbmd0aWFuZ2VuQGh1YXdlaS5jb20vCgpUaGFua3MsClRvbmcuCgo+IAo+IFRoYW5rcywKPiBk cmV3Cj4gLgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18K bGludXgtcmlzY3YgbWFpbGluZyBsaXN0CmxpbnV4LXJpc2N2QGxpc3RzLmluZnJhZGVhZC5vcmcK aHR0cDovL2xpc3RzLmluZnJhZGVhZC5vcmcvbWFpbG1hbi9saXN0aW5mby9saW51eC1yaXNjdgo= 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3F7BCECAAA3 for ; Fri, 26 Aug 2022 06:45:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245077AbiHZGo7 (ORCPT ); Fri, 26 Aug 2022 02:44:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243137AbiHZGoz (ORCPT ); Fri, 26 Aug 2022 02:44:55 -0400 Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6AF061EAE5 for ; Thu, 25 Aug 2022 23:44:52 -0700 (PDT) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.56]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4MDVZk42sGzYcpx; Fri, 26 Aug 2022 14:40:30 +0800 (CST) Received: from kwepemm600017.china.huawei.com (7.193.23.234) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 26 Aug 2022 14:44:49 +0800 Received: from [10.174.179.234] (10.174.179.234) by kwepemm600017.china.huawei.com (7.193.23.234) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Fri, 26 Aug 2022 14:44:48 +0800 Message-ID: <7718a9bc-e976-daeb-f490-e7b5190e50b6@huawei.com> Date: Fri, 26 Aug 2022 14:44:48 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Thunderbird/91.8.0 Subject: Re: [PATCH -next v2 2/2] riscv: extable: add new extable type EX_TYPE_KACCESS_ERR_ZERO support To: Andrew Jones CC: Paul Walmsley , Palmer Dabbelt , Palmer Dabbelt , Albert Ou , , , , , Guohanjun References: <20220815032025.2685516-1-tongtiangen@huawei.com> <20220815032025.2685516-3-tongtiangen@huawei.com> <20220825110602.bog5mjpascvikwxx@kamzik> From: Tong Tiangen In-Reply-To: <20220825110602.bog5mjpascvikwxx@kamzik> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Originating-IP: [10.174.179.234] X-ClientProxiedBy: dggems702-chm.china.huawei.com (10.3.19.179) To kwepemm600017.china.huawei.com (7.193.23.234) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/8/25 19:06, Andrew Jones 写道: > On Mon, Aug 15, 2022 at 03:20:25AM +0000, Tong Tiangen wrote: >> Currently, The extable type EX_TYPE_UACCESS_ERR_ZERO is used by >> __get/put_kernel_nofault(), but those helpers are not uaccess type, so we >> add a new extable type EX_TYPE_KACCESS_ERR_ZERO which can be used by >> __get/put_kernel_no_fault(). >> >> Only refactor code without any functional changes. > > This isn't quite true. __get/put_kernel_nofault now sets a different > extable type (as the commit message says). But, nothing special seems > to be done with that, so there's effectively no functional change. Can > you please elaborate on the motivation for this change? Where will the > KACCESS type need to be distinguished from the UACCESS type? The introduction of EX_TYPE_KACCESS_ERR_ZERO does not change any function, but makes a correct distinction in the actual type, indicating that there are indeed some kaccess entries in extable. I think this optimization is more clear and reasonable. A few weeks ago, I did something similar on arm64[1]. I think this optimization can also be used on riscv. We can do some features that are used on uaccss but not applicable on kaccess in the future[2]. [1] https://lore.kernel.org/lkml/20220621072638.1273594-2-tongtiangen@huawei.com/ [2]https://lore.kernel.org/lkml/20220812070557.1028499-4-tongtiangen@huawei.com/ Thanks, Tong. > > Thanks, > drew > .