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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 76679C433F5 for ; Wed, 25 May 2022 08:32:11 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4L7PST46WRz3bsP for ; Wed, 25 May 2022 18:32:09 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=arm.com (client-ip=217.140.110.172; helo=foss.arm.com; envelope-from=mark.rutland@arm.com; receiver=) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lists.ozlabs.org (Postfix) with ESMTP id 4L7PRz4QDNz303k for ; Wed, 25 May 2022 18:31:41 +1000 (AEST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 24AEB1FB; Wed, 25 May 2022 01:31:08 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.0.228]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F3E743F73D; Wed, 25 May 2022 01:31:02 -0700 (PDT) Date: Wed, 25 May 2022 09:30:55 +0100 From: Mark Rutland To: Tong Tiangen Subject: Re: [PATCH -next v4 3/7] arm64: add support for machine check error safe Message-ID: References: <20220420030418.3189040-1-tongtiangen@huawei.com> <20220420030418.3189040-4-tongtiangen@huawei.com> <46e5954c-a9a8-f4a8-07cc-de42e2753051@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <46e5954c-a9a8-f4a8-07cc-de42e2753051@huawei.com> X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kefeng Wang , Dave Hansen , linux-mm@kvack.org, Paul Mackerras , Guohanjun , Will Deacon , "H . Peter Anvin" , x86@kernel.org, Ingo Molnar , Catalin Marinas , Xie XiuQi , Borislav Petkov , Alexander Viro , Thomas Gleixner , linux-arm-kernel@lists.infradead.org, Robin Murphy , linux-kernel@vger.kernel.org, James Morse , Andrew Morton , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, May 19, 2022 at 02:29:54PM +0800, Tong Tiangen wrote: > > > 在 2022/5/13 23:26, Mark Rutland 写道: > > On Wed, Apr 20, 2022 at 03:04:14AM +0000, Tong Tiangen wrote: > > > During the processing of arm64 kernel hardware memory errors(do_sea()), if > > > the errors is consumed in the kernel, the current processing is panic. > > > However, it is not optimal. > > > > > > Take uaccess for example, if the uaccess operation fails due to memory > > > error, only the user process will be affected, kill the user process > > > and isolate the user page with hardware memory errors is a better choice. > > > > Conceptually, I'm fine with the idea of constraining what we do for a > > true uaccess, but I don't like the implementation of this at all, and I > > think we first need to clean up the arm64 extable usage to clearly > > distinguish a uaccess from another access. > > OK,using EX_TYPE_UACCESS and this extable type could be recover, this is > more reasonable. Great. > For EX_TYPE_UACCESS_ERR_ZERO, today we use it for kernel accesses in a > couple of cases, such as > get_user/futex/__user_cache_maint()/__user_swpX_asm(), Those are all user accesses. However, __get_kernel_nofault() and __put_kernel_nofault() use EX_TYPE_UACCESS_ERR_ZERO by way of __{get,put}_mem_asm(), so we'd need to refactor that code to split the user/kernel cases higher up the callchain. > your suggestion is: > get_user continues to use EX_TYPE_UACCESS_ERR_ZERO and the other cases use > new type EX_TYPE_FIXUP_ERR_ZERO? Yes, that's the rough shape. We could make the latter EX_TYPE_KACCESS_ERR_ZERO to be clearly analogous to EX_TYPE_UACCESS_ERR_ZERO, and with that I susepct we could remove EX_TYPE_FIXUP. Thanks, Mark. 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 6D9DDC433F5 for ; Wed, 25 May 2022 08:32:20 +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-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=5Xkwq7D1Ea+fVZU5RRRnxD2+prqSWzQ/YRqSMEHINug=; b=y9q8pPs3zDVALo RSYO8aScUNrXUu4+e1xs+9Ti6fQxDw1PHvvkvPMAMiAAeSU49llGjnsupRFScPRJ7wrst/60RPH8S FA2upMEuRTivPR377qJMwgrjGgF+ftE4tOZkBlHM7ueTwdeNpVF2T1UKE2S7hxf4pY9tDxHYkcLqe PqkiWKX9pzraIBHuA1qWZuB4l8qYv9+Jj21oRkmPLCqF5DulDkfssM84juOTLbHeIXBXlfjdLu0hm UoMA+B2+e+0CKzH0kHlf82vozh/xHkByY7j8s0rlL1gK29V0FLUhdkHeLRpy+cDDEIlTT+DXVzvAU hxvysswS/eet02zVhJmg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ntmQD-00AQp6-83; Wed, 25 May 2022 08:31:13 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1ntmQ9-00AQnl-Fa for linux-arm-kernel@lists.infradead.org; Wed, 25 May 2022 08:31:10 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 24AEB1FB; Wed, 25 May 2022 01:31:08 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.0.228]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F3E743F73D; Wed, 25 May 2022 01:31:02 -0700 (PDT) Date: Wed, 25 May 2022 09:30:55 +0100 From: Mark Rutland To: Tong Tiangen Cc: James Morse , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Robin Murphy , Dave Hansen , Catalin Marinas , Will Deacon , Alexander Viro , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , x86@kernel.org, "H . Peter Anvin" , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kefeng Wang , Xie XiuQi , Guohanjun Subject: Re: [PATCH -next v4 3/7] arm64: add support for machine check error safe Message-ID: References: <20220420030418.3189040-1-tongtiangen@huawei.com> <20220420030418.3189040-4-tongtiangen@huawei.com> <46e5954c-a9a8-f4a8-07cc-de42e2753051@huawei.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <46e5954c-a9a8-f4a8-07cc-de42e2753051@huawei.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220525_013109_612902_84976B0E X-CRM114-Status: GOOD ( 23.64 ) 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="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org T24gVGh1LCBNYXkgMTksIDIwMjIgYXQgMDI6Mjk6NTRQTSArMDgwMCwgVG9uZyBUaWFuZ2VuIHdy b3RlOgo+IAo+IAo+IOWcqCAyMDIyLzUvMTMgMjM6MjYsIE1hcmsgUnV0bGFuZCDlhpnpgZM6Cj4g PiBPbiBXZWQsIEFwciAyMCwgMjAyMiBhdCAwMzowNDoxNEFNICswMDAwLCBUb25nIFRpYW5nZW4g d3JvdGU6Cj4gPiA+IER1cmluZyB0aGUgcHJvY2Vzc2luZyBvZiBhcm02NCBrZXJuZWwgaGFyZHdh cmUgbWVtb3J5IGVycm9ycyhkb19zZWEoKSksIGlmCj4gPiA+IHRoZSBlcnJvcnMgaXMgY29uc3Vt ZWQgaW4gdGhlIGtlcm5lbCwgdGhlIGN1cnJlbnQgcHJvY2Vzc2luZyBpcyBwYW5pYy4KPiA+ID4g SG93ZXZlciwgaXQgaXMgbm90IG9wdGltYWwuCj4gPiA+IAo+ID4gPiBUYWtlIHVhY2Nlc3MgZm9y IGV4YW1wbGUsIGlmIHRoZSB1YWNjZXNzIG9wZXJhdGlvbiBmYWlscyBkdWUgdG8gbWVtb3J5Cj4g PiA+IGVycm9yLCBvbmx5IHRoZSB1c2VyIHByb2Nlc3Mgd2lsbCBiZSBhZmZlY3RlZCwga2lsbCB0 aGUgdXNlciBwcm9jZXNzCj4gPiA+IGFuZCBpc29sYXRlIHRoZSB1c2VyIHBhZ2Ugd2l0aCBoYXJk d2FyZSBtZW1vcnkgZXJyb3JzIGlzIGEgYmV0dGVyIGNob2ljZS4KPiA+IAo+ID4gQ29uY2VwdHVh bGx5LCBJJ20gZmluZSB3aXRoIHRoZSBpZGVhIG9mIGNvbnN0cmFpbmluZyB3aGF0IHdlIGRvIGZv ciBhCj4gPiB0cnVlIHVhY2Nlc3MsIGJ1dCBJIGRvbid0IGxpa2UgdGhlIGltcGxlbWVudGF0aW9u IG9mIHRoaXMgYXQgYWxsLCBhbmQgSQo+ID4gdGhpbmsgd2UgZmlyc3QgbmVlZCB0byBjbGVhbiB1 cCB0aGUgYXJtNjQgZXh0YWJsZSB1c2FnZSB0byBjbGVhcmx5Cj4gPiBkaXN0aW5ndWlzaCBhIHVh Y2Nlc3MgZnJvbSBhbm90aGVyIGFjY2Vzcy4KPiAKPiBPSyx1c2luZyBFWF9UWVBFX1VBQ0NFU1Mg YW5kIHRoaXMgZXh0YWJsZSB0eXBlIGNvdWxkIGJlIHJlY292ZXIsIHRoaXMgaXMKPiBtb3JlIHJl YXNvbmFibGUuCgpHcmVhdC4KCj4gRm9yIEVYX1RZUEVfVUFDQ0VTU19FUlJfWkVSTywgdG9kYXkg d2UgdXNlIGl0IGZvciBrZXJuZWwgYWNjZXNzZXMgaW4gYQo+IGNvdXBsZSBvZiBjYXNlcywgc3Vj aCBhcwo+IGdldF91c2VyL2Z1dGV4L19fdXNlcl9jYWNoZV9tYWludCgpL19fdXNlcl9zd3BYX2Fz bSgpLCAKClRob3NlIGFyZSBhbGwgdXNlciBhY2Nlc3Nlcy4KCkhvd2V2ZXIsIF9fZ2V0X2tlcm5l bF9ub2ZhdWx0KCkgYW5kIF9fcHV0X2tlcm5lbF9ub2ZhdWx0KCkgdXNlCkVYX1RZUEVfVUFDQ0VT U19FUlJfWkVSTyBieSB3YXkgb2YgX197Z2V0LHB1dH1fbWVtX2FzbSgpLCBzbyB3ZSdkIG5lZWQg dG8KcmVmYWN0b3IgdGhhdCBjb2RlIHRvIHNwbGl0IHRoZSB1c2VyL2tlcm5lbCBjYXNlcyBoaWdo ZXIgdXAgdGhlIGNhbGxjaGFpbi4KCj4geW91ciBzdWdnZXN0aW9uIGlzOgo+IGdldF91c2VyIGNv bnRpbnVlcyB0byB1c2UgRVhfVFlQRV9VQUNDRVNTX0VSUl9aRVJPIGFuZCB0aGUgb3RoZXIgY2Fz ZXMgdXNlCj4gbmV3IHR5cGUgRVhfVFlQRV9GSVhVUF9FUlJfWkVSTz8KClllcywgdGhhdCdzIHRo ZSByb3VnaCBzaGFwZS4gV2UgY291bGQgbWFrZSB0aGUgbGF0dGVyIEVYX1RZUEVfS0FDQ0VTU19F UlJfWkVSTwp0byBiZSBjbGVhcmx5IGFuYWxvZ291cyB0byBFWF9UWVBFX1VBQ0NFU1NfRVJSX1pF Uk8sIGFuZCB3aXRoIHRoYXQgSSBzdXNlcGN0IHdlCmNvdWxkIHJlbW92ZSBFWF9UWVBFX0ZJWFVQ LgoKVGhhbmtzLApNYXJrLgoKX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX18KbGludXgtYXJtLWtlcm5lbCBtYWlsaW5nIGxpc3QKbGludXgtYXJtLWtlcm5lbEBs aXN0cy5pbmZyYWRlYWQub3JnCmh0dHA6Ly9saXN0cy5pbmZyYWRlYWQub3JnL21haWxtYW4vbGlz dGluZm8vbGludXgtYXJtLWtlcm5lbAo= 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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 73B85C433EF for ; Wed, 25 May 2022 08:31:10 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 064438D0002; Wed, 25 May 2022 04:31:10 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id F32338D0001; Wed, 25 May 2022 04:31:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E1F9C8D0002; Wed, 25 May 2022 04:31:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id D4CC68D0001 for ; Wed, 25 May 2022 04:31:09 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay12.hostedemail.com (Postfix) with ESMTP id BBB07120EAC for ; Wed, 25 May 2022 08:31:09 +0000 (UTC) X-FDA: 79503595458.21.1D8BDE8 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf08.hostedemail.com (Postfix) with ESMTP id 9A149160031 for ; Wed, 25 May 2022 08:30:47 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 24AEB1FB; Wed, 25 May 2022 01:31:08 -0700 (PDT) Received: from FVFF77S0Q05N (unknown [10.57.0.228]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F3E743F73D; Wed, 25 May 2022 01:31:02 -0700 (PDT) Date: Wed, 25 May 2022 09:30:55 +0100 From: Mark Rutland To: Tong Tiangen Cc: James Morse , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Robin Murphy , Dave Hansen , Catalin Marinas , Will Deacon , Alexander Viro , Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , x86@kernel.org, "H . Peter Anvin" , linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Kefeng Wang , Xie XiuQi , Guohanjun Subject: Re: [PATCH -next v4 3/7] arm64: add support for machine check error safe Message-ID: References: <20220420030418.3189040-1-tongtiangen@huawei.com> <20220420030418.3189040-4-tongtiangen@huawei.com> <46e5954c-a9a8-f4a8-07cc-de42e2753051@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <46e5954c-a9a8-f4a8-07cc-de42e2753051@huawei.com> X-Rspamd-Queue-Id: 9A149160031 X-Stat-Signature: zgski3ayueoichjntoqh5krqemxkupud Authentication-Results: imf08.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf08.hostedemail.com: domain of mark.rutland@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=mark.rutland@arm.com X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1653467447-527323 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, May 19, 2022 at 02:29:54PM +0800, Tong Tiangen wrote: > > > 在 2022/5/13 23:26, Mark Rutland 写道: > > On Wed, Apr 20, 2022 at 03:04:14AM +0000, Tong Tiangen wrote: > > > During the processing of arm64 kernel hardware memory errors(do_sea()), if > > > the errors is consumed in the kernel, the current processing is panic. > > > However, it is not optimal. > > > > > > Take uaccess for example, if the uaccess operation fails due to memory > > > error, only the user process will be affected, kill the user process > > > and isolate the user page with hardware memory errors is a better choice. > > > > Conceptually, I'm fine with the idea of constraining what we do for a > > true uaccess, but I don't like the implementation of this at all, and I > > think we first need to clean up the arm64 extable usage to clearly > > distinguish a uaccess from another access. > > OK,using EX_TYPE_UACCESS and this extable type could be recover, this is > more reasonable. Great. > For EX_TYPE_UACCESS_ERR_ZERO, today we use it for kernel accesses in a > couple of cases, such as > get_user/futex/__user_cache_maint()/__user_swpX_asm(), Those are all user accesses. However, __get_kernel_nofault() and __put_kernel_nofault() use EX_TYPE_UACCESS_ERR_ZERO by way of __{get,put}_mem_asm(), so we'd need to refactor that code to split the user/kernel cases higher up the callchain. > your suggestion is: > get_user continues to use EX_TYPE_UACCESS_ERR_ZERO and the other cases use > new type EX_TYPE_FIXUP_ERR_ZERO? Yes, that's the rough shape. We could make the latter EX_TYPE_KACCESS_ERR_ZERO to be clearly analogous to EX_TYPE_UACCESS_ERR_ZERO, and with that I susepct we could remove EX_TYPE_FIXUP. Thanks, Mark.