From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1hHRwR-0003SM-Pp for kexec@lists.infradead.org; Fri, 19 Apr 2019 11:44:29 +0000 Date: Fri, 19 Apr 2019 19:44:21 +0800 From: Baoquan He Subject: Re: [RFC PATCH] kexec, x86/boot: map systab region in identity mapping before accessing it Message-ID: <20190419114421.GH11060@MiWiFi-R3L-srv> References: <20190419101733.GA10324@zn.tnic> <20190419105014.GE11060@MiWiFi-R3L-srv> <20190419112801.GB10324@zn.tnic> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190419112801.GB10324@zn.tnic> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: Borislav Petkov Cc: "x86@kernel.org" , Kairui Song , Chao Fan , "kexec@lists.infradead.org" , linux-kernel@vger.kernel.org, Junichi Nomura , Thomas Gleixner , Dave Young On 04/19/19 at 01:28pm, Borislav Petkov wrote: > Why does that "seem" so? > > Read again what I said: "should all be passed through boot_params". > Which means, boot_params should be extended with a field of a flag to > say: "this is a kexec'ed kernel". > > If it "seems" then it should be made to not "seem" but to work properly. No objection to extending with fields of a flag to mark kexec'ed kernel. Or kdump kernel either. We now check kdump kernel by /proc/vmcore. > > > Yeah, adding the systab mapping looks good. Kairui put it in > > decompressing stage just because he wants to cover the case in which the > > old kernel kexec jumping to 2nd kernel. Now it seems not very > > reasonable, we also have the new kernel kexec jumping to old 2nd kernel. > > I don't think we can guarantee kexec between old<->new kernel to always > work. Otherwise, we can forget all development and improvements of new > kernel. I personally agree with this. Very earlier, we tried to remove the 896 MB limitation of crashkernel=xM, to extend it to 4G or the whole RAM, but rejcted by linus since he worried it could break the old kernel kdumping. I may not remember well. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec