Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751194AbaKYRsI (ORCPT ); Tue, 25 Nov 2014 12:48:08 -0500 Received: from mail.skyhub.de ([78.46.96.112]:50233 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750809AbaKYRsE (ORCPT ); Tue, 25 Nov 2014 12:48:04 -0500 Date: Tue, 25 Nov 2014 18:48:00 +0100 From: Borislav Petkov To: Matt Fleming Cc: Ard Biesheuvel , leif.lindholm@linaro.org, roy.franz@linaro.org, linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, msalter@redhat.com, dyoung@redhat.com, linux-efi@vger.kernel.org, matt.fleming@intel.com, will.deacon@arm.com, catalin.marinas@arm.com, grant.likely@linaro.org, geoff.levand@linaro.org, linux-kernel@vger.kernel.org, Peter Jones Subject: Re: [PATCH v3 03/13] arm64: improve CONFIG_STRICT_DEVMEM handling Message-ID: <20141125174800.GA3938@pd.tnic> References: <1416315432-8534-1-git-send-email-ard.biesheuvel@linaro.org> <1416315432-8534-4-git-send-email-ard.biesheuvel@linaro.org> <20141125173925.GE3331@console-pimps.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20141125173925.GE3331@console-pimps.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 25, 2014 at 05:39:25PM +0000, Matt Fleming wrote: > On Tue, 18 Nov, at 01:57:02PM, Ard Biesheuvel wrote: > > Improve the handling of /dev/mem mappings under CONFIG_STRICT_DEVMEM by: > > - allowing read-only access to parts of System RAM that are not > > considered memory by the kernel, this is mainly intended for exposing > > UEFI Configuration tables to userland; > > - avoid using non-cached mappings for those parts of System RAM, as it > > may result in mismatched attributes. > > Is this really the best way to expose EFI config tables? > > We already have parts in /sys/firmware/efi/ and in particular we expose > the runtime mappings there for kexec on x86. Yeah! > Hooking this into the /dev/mem infrastructure just seems wrong to me. And this virtmap.c thing is arm-only, AFAICT, but it looks like generic code and like a wholly new way of doing the efi page table. This thing needs to be properly split into generic pieces which go into drivers/firmware/efi/ and arm-specific which would make that EFI_VIRTMAP into an arch bit. And so on and so on... -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/