From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0A5C4C433F5 for ; Fri, 20 May 2022 12:30:47 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4L4R0556gyz3bmR for ; Fri, 20 May 2022 22:30:45 +1000 (AEST) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=n//aSrT8; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=kernel.org (client-ip=139.178.84.217; helo=dfw.source.kernel.org; envelope-from=pali@kernel.org; receiver=) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=n//aSrT8; dkim-atps=neutral Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4L4QzQ2MTKz2yK2 for ; Fri, 20 May 2022 22:30:10 +1000 (AEST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2FAC061E07; Fri, 20 May 2022 12:30:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 351AEC385A9; Fri, 20 May 2022 12:30:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1653049806; bh=AqlsiTiDuwleDs60bALNrrGbJz64ZW8+v9vBuAfjIdE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=n//aSrT8ReVB2j6Z6WCHL/0E27hvzGhZhsyLSdtYHrlW7pApWXEOxRsVVHnaPu4by 7jZvcFfdaRPJj8AShcRrqy/G/9Te5hyyU7E031UruMFJyaqVbdSwmBokv3CR6j+NFV Xvb4JAUzvnOOXOLojKlgRveQavW5WHUqP2IibyHS3HXgnUQyS+FKQ6TrTslYASokRK UXuFIwAZ5/9Sz3inokKAhG1YblBR8djEbp9loldJhx+kXD+Y5rD9nCya7K44TDqIgT OAdD+mqc1Tu/4Mst2Bl6M7wV6q3Mi3l1Kpwcvu+SAKT0ERpwyYafOGKoDWhVoDmPp2 3TdVlbbVTcZOA== Received: by pali.im (Postfix) id E90F45F2; Fri, 20 May 2022 14:30:02 +0200 (CEST) Date: Fri, 20 May 2022 14:30:02 +0200 From: Pali =?utf-8?B?Um9ow6Fy?= To: linux-mm@kvack.org Subject: Re: [PATCH 11/12] powerpc: wiiu: don't enforce flat memory Message-ID: <20220520123002.rd46p5ty6wumi7cc@pali> References: <20220302044406.63401-1-ash@heyquark.com> <20220302044406.63401-12-ash@heyquark.com> <20220513224353.n56qg5fhstbaqhfz@pali> <20220520080454.c3cqodsdbfbkmg56@pali> <935b426a-6c64-beb0-907f-8c3f0a089ab7@heyquark.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <935b426a-6c64-beb0-907f-8c3f0a089ab7@heyquark.com> User-Agent: NeoMutt/20180716 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-kernel@vger.kernel.org, robh+dt@kernel.org, paulus@samba.org, Ash Logan , linuxppc-dev@lists.ozlabs.org, j.ne@posteo.net Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" + linux-mm Do you know what are requirements for kernel to support non-contiguous memory support and what is needed to enable it for 32-bit powerpc? Currently powerpc arch code does not support "memblock.memory.cnt > 1" except for WII which seems like a hack... See below. On Friday 20 May 2022 20:44:04 Ash Logan wrote: > On 20/5/22 18:04, Pali Rohár wrote: > > On Friday 20 May 2022 13:41:04 Ash Logan wrote: > >> On 14/5/22 08:43, Pali Rohár wrote: > >>> On Wednesday 02 March 2022 15:44:05 Ash Logan wrote: > >>>> pgtable_32.c:mapin_ram loops over each valid memory range, which means > >>>> non-contiguous memory just works. > >>> > >>> Hello! Does it mean that non-contiguous memory works for any 32-bit > >>> powerpc platform, and not only for wiiu? If yes, should not be > >>> non-contiguous memory support enabled for all 32-bit ppc boards then? > >> > >> Hi! Sorry for my delayed response. As best I can tell, it does indeed > >> Just Work, but I have only been able to test on wiiu which is missing a > >> lot of features other boards have (like PCI) - so it's possible there's > >> still an assumption elsewhere in the kernel that I haven't hit. > >> > >> As best I can tell, the Wii and Wii U are the only 32-bit powerpc boards > >> out there where it's even possible to have non-contiguous memory. > > > > What is the reason that those two boards are the **only**? Is there some > > specific requirement from bootloader or hardware to "enable" > > non-contiguous memory support? > > Not that I know of, I was just saying that I was only aware of those two > boards where the memory map isn't contiguous, and that is the only place > where it has been tested. Evidently you know of another board! > > > I'm interested in enabling non-contiguous memory support for P2020-based > > board as it has gaps in its 32-bit memory layout and which could be used > > for RAM mapping when 4GB DDR3 module is plugged in (default is 2GB). > > If it's like the Wii or Wii U (some memory at 0, a gap for MMIO or > whatever, then more memory at a higher address) then you should try a > patch along these lines, because barring the unknowns I mentioned before > it should work. At least as far as I'm aware ;) > > >>>> Signed-off-by: Ash Logan > >>>> --- > >>>> arch/powerpc/mm/init_32.c | 4 ++-- > >>>> 1 file changed, 2 insertions(+), 2 deletions(-) > >>>> > >>>> diff --git a/arch/powerpc/mm/init_32.c b/arch/powerpc/mm/init_32.c > >>>> index 3d690be48e84..59a84629d9a0 100644 > >>>> --- a/arch/powerpc/mm/init_32.c > >>>> +++ b/arch/powerpc/mm/init_32.c > >>>> @@ -125,10 +125,10 @@ void __init MMU_init(void) > >>>> * lowmem_end_addr is initialized below. > >>>> */ > >>>> if (memblock.memory.cnt > 1) { > >>>> -#ifndef CONFIG_WII > >>>> +#if !defined(CONFIG_WII) && !defined(CONFIG_WIIU) > >>>> memblock_enforce_memory_limit(memblock.memory.regions[0].size); > >>>> pr_warn("Only using first contiguous memory region\n"); > >>>> -#else > >>>> +#elif defined(CONFIG_WII) > >>>> wii_memory_fixups(); > >>>> #endif > >>>> } > >>>> -- > >>>> 2.35.1 > >>>>