From mboxrd@z Thu Jan 1 00:00:00 1970 From: panand@redhat.com (Pratyush Anand) Date: Wed, 14 Dec 2016 15:42:22 +0530 Subject: [PATCH 1/2] arm64: Add enable/disable d-cache support for purgatory In-Reply-To: References: <7a4866b928c0905ec1074dce1bfc7984c968a58a.1479788404.git.panand@redhat.com> <5838834D.90205@arm.com> Message-ID: <9a79b666-7990-2a23-2d74-52b3317ce272@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wednesday 14 December 2016 03:08 PM, Pratyush Anand wrote: > >> >> I would go as far as to generate the page tables at 'kexec -l' time, >> and only if > > Ok..So you mean that I create a new section which will have page table > entries mapping physicalmemory represented by remaining section, and > then purgatory can just enable mmu with page table from that section, > right? Seems doable. can do that. I see a problem here. If we create page table as a new segment then, how can we verify in purgatory that sha for page table is correct? We need page table before sha verification start,and we can not rely the page table created by first kernel until it's sha is verified. So a chicken-egg problem. I think, creating page table will just take fraction of second and should be good even in purgatory, What do you say? ~Pratyush From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-qk0-f169.google.com ([209.85.220.169]) by bombadil.infradead.org with esmtps (Exim 4.85_2 #1 (Red Hat Linux)) id 1cH6YL-0008L0-TM for kexec@lists.infradead.org; Wed, 14 Dec 2016 10:12:52 +0000 Received: by mail-qk0-f169.google.com with SMTP id q130so14117328qke.1 for ; Wed, 14 Dec 2016 02:12:29 -0800 (PST) Subject: Re: [PATCH 1/2] arm64: Add enable/disable d-cache support for purgatory References: <7a4866b928c0905ec1074dce1bfc7984c968a58a.1479788404.git.panand@redhat.com> <5838834D.90205@arm.com> From: Pratyush Anand Message-ID: <9a79b666-7990-2a23-2d74-52b3317ce272@redhat.com> Date: Wed, 14 Dec 2016 15:42:22 +0530 MIME-Version: 1.0 In-Reply-To: List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: James Morse Cc: geoff@infradead.org, Mark Rutland , kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org On Wednesday 14 December 2016 03:08 PM, Pratyush Anand wrote: > >> >> I would go as far as to generate the page tables at 'kexec -l' time, >> and only if > > Ok..So you mean that I create a new section which will have page table > entries mapping physicalmemory represented by remaining section, and > then purgatory can just enable mmu with page table from that section, > right? Seems doable. can do that. I see a problem here. If we create page table as a new segment then, how can we verify in purgatory that sha for page table is correct? We need page table before sha verification start,and we can not rely the page table created by first kernel until it's sha is verified. So a chicken-egg problem. I think, creating page table will just take fraction of second and should be good even in purgatory, What do you say? ~Pratyush _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec