From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757105AbbEVMxw (ORCPT ); Fri, 22 May 2015 08:53:52 -0400 Received: from foss.arm.com ([217.140.101.70]:43687 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756418AbbEVMxv (ORCPT ); Fri, 22 May 2015 08:53:51 -0400 Date: Fri, 22 May 2015 13:53:46 +0100 From: Catalin Marinas To: Mark Salter Cc: Matt Fleming , Ard Biesheuvel , Will Deacon , "linux-kernel@vger.kernel.org" , Hanjun Guo , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] arm64: support ACPI tables outside of kernel RAM Message-ID: <20150522125346.GX29424@e104818-lin.cambridge.arm.com> References: <1431613373-10928-1-git-send-email-msalter@redhat.com> <20150518111143.GC21251@e104818-lin.cambridge.arm.com> <1431957525.9933.4.camel@deneb.redhat.com> <20150518164108.GH21251@e104818-lin.cambridge.arm.com> <20150522103417.GT29424@e104818-lin.cambridge.arm.com> <1432298762.9933.58.camel@deneb.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1432298762.9933.58.camel@deneb.redhat.com> 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 Fri, May 22, 2015 at 08:46:02AM -0400, Mark Salter wrote: > On Fri, 2015-05-22 at 11:34 +0100, Catalin Marinas wrote: > > OK, so my preferred options, in this order: > > > > 1. Change the core ACPI kernel code to distinguish between mapping I/O > > or RAM (could be as simple as acpi_map not using acpi_os_ioremap but > > another API). I guess the code knows when it plans to map tables or > > I/O registers > > > > 2. If the above is not possible, add the extra checks as per Mark's > > patch but I would rather call this resource "UEFI RAM" than "ACPI", > > it's not really ACPI specific. > > Actually, it is ACPI specific. The patch only registers resources for > EfiACPIReclaimMemory and EfiACPIMemoryNVS regions which are also > marked as cacheable. On x86 these show up in /proc/iomem as > "ACPI Tables" and "ACPI Non-volatile Storage". I used "ACPI RAM" to > avoid having to search for two strings. My point is more about UEFI describing the entire RAM while the kernel command line restricts it via "mem=". In this case, the "System RAM" resources is reduced as well but it does not necessarily mean that the rest of the RAM is only used by ACPI. -- Catalin From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Fri, 22 May 2015 13:53:46 +0100 Subject: [PATCH] arm64: support ACPI tables outside of kernel RAM In-Reply-To: <1432298762.9933.58.camel@deneb.redhat.com> References: <1431613373-10928-1-git-send-email-msalter@redhat.com> <20150518111143.GC21251@e104818-lin.cambridge.arm.com> <1431957525.9933.4.camel@deneb.redhat.com> <20150518164108.GH21251@e104818-lin.cambridge.arm.com> <20150522103417.GT29424@e104818-lin.cambridge.arm.com> <1432298762.9933.58.camel@deneb.redhat.com> Message-ID: <20150522125346.GX29424@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, May 22, 2015 at 08:46:02AM -0400, Mark Salter wrote: > On Fri, 2015-05-22 at 11:34 +0100, Catalin Marinas wrote: > > OK, so my preferred options, in this order: > > > > 1. Change the core ACPI kernel code to distinguish between mapping I/O > > or RAM (could be as simple as acpi_map not using acpi_os_ioremap but > > another API). I guess the code knows when it plans to map tables or > > I/O registers > > > > 2. If the above is not possible, add the extra checks as per Mark's > > patch but I would rather call this resource "UEFI RAM" than "ACPI", > > it's not really ACPI specific. > > Actually, it is ACPI specific. The patch only registers resources for > EfiACPIReclaimMemory and EfiACPIMemoryNVS regions which are also > marked as cacheable. On x86 these show up in /proc/iomem as > "ACPI Tables" and "ACPI Non-volatile Storage". I used "ACPI RAM" to > avoid having to search for two strings. My point is more about UEFI describing the entire RAM while the kernel command line restricts it via "mem=". In this case, the "System RAM" resources is reduced as well but it does not necessarily mean that the rest of the RAM is only used by ACPI. -- Catalin