From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi1-f199.google.com (mail-oi1-f199.google.com [209.85.167.199]) by kanga.kvack.org (Postfix) with ESMTP id 7A05B6B7A21 for ; Thu, 6 Dec 2018 09:35:28 -0500 (EST) Received: by mail-oi1-f199.google.com with SMTP id a62so258293oii.23 for ; Thu, 06 Dec 2018 06:35:28 -0800 (PST) Received: from foss.arm.com (usa-sjc-mx-foss1.foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id a66si200345otb.92.2018.12.06.06.35.24 for ; Thu, 06 Dec 2018 06:35:24 -0800 (PST) Subject: Re: [PATCH V4 5/6] arm64: mm: introduce 52-bit userspace support References: <20181205164145.24568-1-steve.capper@arm.com> <20181205164145.24568-6-steve.capper@arm.com> <20181206122603.GB17473@capper-debian.cambridge.arm.com> From: Suzuki K Poulose Message-ID: Date: Thu, 6 Dec 2018 14:35:20 +0000 MIME-Version: 1.0 In-Reply-To: <20181206122603.GB17473@capper-debian.cambridge.arm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Steve Capper Cc: "linux-mm@kvack.org" , "linux-arm-kernel@lists.infradead.org" , Catalin Marinas , Will Deacon , "jcm@redhat.com" , "ard.biesheuvel@linaro.org" , nd On 06/12/2018 12:26, Steve Capper wrote: > On Wed, Dec 05, 2018 at 06:22:27PM +0000, Suzuki K Poulose wrote: >> Hi Steve, >> > [...] >> I think we may need a check for the secondary CPUs to make sure that they have >> the 52bit support once the boot CPU has decided to use the feature and fail the >> CPU bring up (just like we do for the granule support). >> >> Suzuki > > Hi Suzuki, > I have just written a patch to detect a mismatch between 52-bit VA that > is being tested now. > > As 52-bit kernel VA support is coming in future, the patch checks for a > mismatch during the secondary boot path and, if one is found, prevents > the secondary from booting (and displays an error message to the user). Right now, it is the boot CPU which decides the Userspace 52bit VA, isn't it ? Irrespective of the kernel VA support, the userspace must be able to run on all the CPUs on the system, right ? So don't we need it now, with this series ? Cheers Suzuki 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=-2.7 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED 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 127FDC04EB8 for ; Thu, 6 Dec 2018 14:35:45 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D611620672 for ; Thu, 6 Dec 2018 14:35:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="B3IXE8b6" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D611620672 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-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=bombadil.20170209; h=Sender:Content-Type: Content-Transfer-Encoding:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:Date:Message-ID:From: References:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=1FsEgkhr5aajSoBHYqVFmTh/ySfXemWeykLDGTmR258=; b=B3IXE8b6btF3/1zJiknwcDwCd t56wNWeudFN8z76YLaYArK7nlhLGFhoSJxRsnsFLdco4RQLbVmvbSh2IgoUbSL3jzpeWBeZTWblVc 3BHhQo9JBxWL6PjP3JxvHC4Y3q6iBfyB61J+v/XVBqLAbfcVw0JjIgZdAYhKcdd5YKizR3x1yVxyf ONhY08C0YAT+awtlVOhIM1H4iFSAy13heV1X2tYy2ecbk/WS6cpR7wY7WhPTZnd0w9rGAVH89y9RG S2lxXSOFCIfKtjb6nUEe2f5p0hZBAkOjkiEEvtwcQVGoID4qnjbpkIZ+IpsXSfsC27JHU0DtPOaKb 3vkCgj32Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gUukf-0003Em-Lj; Thu, 06 Dec 2018 14:35:41 +0000 Received: from foss.arm.com ([217.140.101.70]) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gUukc-0003EK-JJ for linux-arm-kernel@lists.infradead.org; Thu, 06 Dec 2018 14:35:39 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 925E4A78; Thu, 6 Dec 2018 06:35:23 -0800 (PST) Received: from [10.1.196.93] (en101.cambridge.arm.com [10.1.196.93]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 19AA03F575; Thu, 6 Dec 2018 06:35:21 -0800 (PST) Subject: Re: [PATCH V4 5/6] arm64: mm: introduce 52-bit userspace support To: Steve Capper References: <20181205164145.24568-1-steve.capper@arm.com> <20181205164145.24568-6-steve.capper@arm.com> <20181206122603.GB17473@capper-debian.cambridge.arm.com> From: Suzuki K Poulose Message-ID: Date: Thu, 6 Dec 2018 14:35:20 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20181206122603.GB17473@capper-debian.cambridge.arm.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20181206_063538_642429_B7F99EEC X-CRM114-Status: GOOD ( 17.81 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "ard.biesheuvel@linaro.org" , "jcm@redhat.com" , Will Deacon , "linux-mm@kvack.org" , Catalin Marinas , nd , "linux-arm-kernel@lists.infradead.org" Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 06/12/2018 12:26, Steve Capper wrote: > On Wed, Dec 05, 2018 at 06:22:27PM +0000, Suzuki K Poulose wrote: >> Hi Steve, >> > [...] >> I think we may need a check for the secondary CPUs to make sure that they have >> the 52bit support once the boot CPU has decided to use the feature and fail the >> CPU bring up (just like we do for the granule support). >> >> Suzuki > > Hi Suzuki, > I have just written a patch to detect a mismatch between 52-bit VA that > is being tested now. > > As 52-bit kernel VA support is coming in future, the patch checks for a > mismatch during the secondary boot path and, if one is found, prevents > the secondary from booting (and displays an error message to the user). Right now, it is the boot CPU which decides the Userspace 52bit VA, isn't it ? Irrespective of the kernel VA support, the userspace must be able to run on all the CPUs on the system, right ? So don't we need it now, with this series ? Cheers Suzuki _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel