From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751682AbeBUHGX (ORCPT ); Wed, 21 Feb 2018 02:06:23 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:44220 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751485AbeBUHGQ (ORCPT ); Wed, 21 Feb 2018 02:06:16 -0500 Subject: Re: [PATCH 0/6] DISCONTIGMEM support for PPC32 To: =?UTF-8?Q?Jonathan_Neusch=c3=a4fer?= , linuxppc-dev@lists.ozlabs.org Cc: Joel Stanley , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20180220161424.5421-1-j.neuschaefer@gmx.net> From: Christophe LEROY Message-ID: <193a407d-e6b8-9e29-af47-3d401b6414a0@c-s.fr> Date: Wed, 21 Feb 2018 08:06:10 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <20180220161424.5421-1-j.neuschaefer@gmx.net> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 20/02/2018 à 17:14, Jonathan Neuschäfer a écrit : > This patchset adds support for DISCONTIGMEM on 32-bit PowerPC. This is > required to properly support the Nintendo Wii's memory layout, in which > there are two blocks of RAM and MMIO in the middle. > > Previously, this memory layout was handled by code that joins the two > RAM blocks into one, reserves the MMIO hole, and permits allocations of > reserved memory in ioremap. This hack didn't work with resource-based > allocation (as used for example in the GPIO driver for Wii[1]), however. > > After this patchset, users of the Wii can either select CONFIG_FLATMEM > to get the old behaviour, or CONFIG_DISCONTIGMEM to get the new > behaviour. My question might me stupid, as I don't know PCC64 in deep, but when looking at page_is_ram() in arch/powerpc/mm/mem.c, I have the feeling the PPC64 implements ram by blocks. Isn't it what you are trying to achieve ? Wouldn't it be feasible to map to what's done in PPC64 for PPC32 ? Christophe > > Some parts of this patchset are probably not ideal (I'm thinking of my > implementation of pfn_to_nid here), and will require some discussion/ > changes. > > [1]: https://www.spinics.net/lists/devicetree/msg213956.html > > Jonathan Neuschäfer (6): > powerpc/mm/32: Use pfn_valid to check if pointer is in RAM > powerpc: numa: Fix overshift on PPC32 > powerpc: numa: Use the right #ifdef guards around functions > powerpc: numa: Restrict fake NUMA enulation to CONFIG_NUMA systems > powerpc: Implement DISCONTIGMEM and allow selection on PPC32 > powerpc: wii: Don't rely on reserved memory hack if DISCONTIGMEM is > set > > arch/powerpc/Kconfig | 5 ++++- > arch/powerpc/include/asm/mmzone.h | 21 +++++++++++++++++++++ > arch/powerpc/mm/numa.c | 18 +++++++++++++++--- > arch/powerpc/mm/pgtable_32.c | 2 +- > arch/powerpc/platforms/embedded6xx/wii.c | 10 +++++++--- > 5 files changed, 48 insertions(+), 8 deletions(-) >