From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x22a.google.com (mail-pa0-x22a.google.com [IPv6:2607:f8b0:400e:c03::22a]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3rlLKd4qwdzDr0f for ; Thu, 7 Jul 2016 11:55:01 +1000 (AEST) Received: by mail-pa0-x22a.google.com with SMTP id uj8so1539409pab.3 for ; Wed, 06 Jul 2016 18:55:01 -0700 (PDT) Date: Thu, 7 Jul 2016 11:00:25 +0900 From: AKASHI Takahiro To: Thiago Jung Bauermann Cc: kexec@lists.infradead.org, catalin.marinas@arm.com, will.deacon@arm.com, geoff@infradead.org, james.morse@arm.com, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v21 8/8] Documentation: dt: usable-memory and elfcorehdr nodes for arm64 kexec Message-ID: <20160707020025.GY20774@linaro.org> References: <20160706075226.27609-1-takahiro.akashi@linaro.org> <20160706075226.27609-9-takahiro.akashi@linaro.org> <6483018.WWW2TSJB10@hactar> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-2022-jp In-Reply-To: <6483018.WWW2TSJB10@hactar> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Wed, Jul 06, 2016 at 04:29:18PM -0300, Thiago Jung Bauermann wrote: > Hi, > > Am Mittwoch, 06 Juli 2016, 16:52:26 schrieb AKASHI Takahiro: > > +linux,usable-memory > > +------------------- > > + > > +This property is set on PowerPC and arm64 by kexec-tools during kdump > > +to tell the crash kernel the base address of its reserved area of memory, > > and +the size. e.g. > > + > > +/ { > > + chosen { > > + linux,usable-memory = <0x9 0xf0000000 0x0 0x10000000>; > > + }; > > +}; > > Again, this description is wrong for PowerPC. See messages from myself and > Michael Ellerman: > > https://lists.infradead.org/pipermail/kexec/2016-June/016250.html > > https://lists.infradead.org/pipermail/kexec/2016-June/016253.html Oops, I must have missed your previous comments. Apologies. Yes, I know that, and I used to implement the same functionality before. It did work for dtb-based systems, but not for UEFI(ACPI)-based systems because UEFI doesn't export memory regions information via a device tree, but rather via ACPI table. So "/memory" node won't appear. So I went back with "mem=" command line approach, and later this "/chosen/" approach. > IMHO, it would be simpler if ARM used linux,usable-memory in the same way > that PowerPC does, for consistency. Well, this property won't conflict with per-"/memory" ones if we take it that the former, if present, supersedes the latter. Sophistic? What about changing the name to usable-memory-limit? (I know that you have another one, "memory-limit" though.) Again, I would like to defer to arm64 maintainers. Thanks, -Takahiro AKASHI > -- > []'s > Thiago Jung Bauermann > IBM Linux Technology Center >