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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 71AA8CAC592 for ; Fri, 19 Sep 2025 14:42:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:CC:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=G8ldK24AiwNDLcBYNMI6Cuki6eZBDjdQT8mYCvvECmw=; b=nwwPjiZu0rB9JoNVwnVQ2rMOpq RNr9I3l9iYOwkehO+M6GtZvnPM0AJ5VxAW2P/3l/ydivI3c0IR012FOxICZ0PNqOOXXddTxdSFGxV v3iWYHfVHw6h7wKlUFe/KxtXeHtpK+ZnZUrD5b35KXZ44Ixk+wG8qzTGjbiPGSD+5P8SpuVlK2C/p Dl+kaBQX3s6iLDp/5bQAzNIHsUPP7+iTGnsuKwIeZug7dotIwt3kLUQArVv0c7h4oyxkf18q80CJr +mvXkHpY0tSV0aDvUVzmrJpLMhHbJxMm+XHVBivOyZcMGNpHSZzVflq89qfbRCmz4USO6oDY2SWsQ +HMQLITQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzcJK-00000003BSZ-0SIo; Fri, 19 Sep 2025 14:42:06 +0000 Received: from esa.microchip.iphmx.com ([68.232.153.233]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uzcJI-00000003BRt-0cgC for linux-arm-kernel@lists.infradead.org; Fri, 19 Sep 2025 14:42:05 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1758292923; x=1789828923; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=BUXNR1hckyrk8jBBQv+MEaTsb/Yxf7QPZcopTVXtsc0=; b=WhiQaPaPqaR1lFxBQ3vVO8C2TnAoYrP81mpJAhfn9EKWqPRpNHfFu4uW TOO5fK6hDTcVD14yW72ZTbdPyxEiAypk3V1f7U3x9XGGIRxn+j4j2gpS9 togGqEx9hOjQpKWiLqN/1qR2jZn+bEvKq6OOO6LAy32U7T28gpN+Ql7Rm BFlvlmvEvtKNReXODXwNIJMzyeQD0T5ecFDsqt8cELGMVPTvLbNhTtEWk ghwVTaQP6NnVvXxPtH+aV86i362XVePfCwBb33qFbbOTL5J0V2O83jL9X Qw9BhdMptEsMFzsxSaE+wW6VP/POVq/qmN6lzm19TL2Ya4uaOH/jU+MhV g==; X-CSE-ConnectionGUID: rCtXrXuCRuWl+rA3xsHEKA== X-CSE-MsgGUID: EJ/u+s4TQLuYDQ4Fe3Jepw== X-IronPort-AV: E=Sophos;i="6.18,278,1751266800"; d="scan'208";a="52617186" X-Amp-Result: SKIPPED(no attachment in message) Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa1.microchip.iphmx.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 19 Sep 2025 07:42:02 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex04.mchp-main.com (10.10.85.152) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.58; Fri, 19 Sep 2025 07:41:32 -0700 Received: from [10.159.245.205] (10.10.85.11) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2507.58 via Frontend Transport; Fri, 19 Sep 2025 07:41:27 -0700 Message-ID: Date: Fri, 19 Sep 2025 16:41:26 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [TECH TOPIC] Reaching consensus on CONFIG_HIGHMEM phaseout To: Geert Uytterhoeven , Arnd Bergmann CC: Jason Gunthorpe , , , , , , , , Christophe Leroy , Richard Weinberger , Lucas Stach , Linus Walleij , Geert Uytterhoeven , Ankur Arora , David Hildenbrand , Mike Rapoport , Lorenzo Stoakes , Matthew Wilcox , Andrew Morton , "Liam R. 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Unal" , Sergio Paracuellos , Andreas Larsson References: <4ff89b72-03ff-4447-9d21-dd6a5fe1550f@app.fastmail.com> <20250917125951.GA1390993@nvidia.com> <02b0f383-1c43-4eeb-a76f-830c2970b833@app.fastmail.com> From: Nicolas Ferre Content-Language: en-US, fr Organization: microchip In-Reply-To: Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250919_074204_200540_F38B288B X-CRM114-Status: GOOD ( 17.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Geert, On 19/09/2025 at 09:17, Geert Uytterhoeven wrote: > Hi Arnd, > > On Thu, 18 Sept 2025 at 15:13, Arnd Bergmann wrote: >> On Wed, Sep 17, 2025, at 14:59, Jason Gunthorpe wrote: >>> On Tue, Sep 09, 2025 at 11:23:37PM +0200, Arnd Bergmann wrote: >>> >>>> I'm still collecting information about which of the remaining highmem >>>> users plan to keep updating their kernels and for what reason. >>> >>> On this topic of removing some parts of highmem, can we say goodbye to >>> kmap_high_get()? Only ARM uses it and only for >>> !cache_is_vipt_nonaliasing() systems. >> >> Good idea. I think we are almost there, just need to verify that >> there is actually no impact for existing users. I already knew >> that there is very little highmem usage on ARMv6 and earlier, but >> I tried to recheck all platforms that might be affected: > >> * Microchip SAM9x7 is the newest ARMv5 chip, clearly does >> get kernel updates, and the only one I can think of with >> DDR3 support, but seems to be limited to 256MB total memory. > > Are they limited to DDR3? For sam9x75: - DDR2 - DDR3 (DLL Off/On mode) - DDR3L (DLL Off/On mode) For (older) sam9x60: - LPDDR1 - DDR2 - SDRAM & Mobile SDRAM > IIRC, someone (you? ;-) told me at ELCE that Microchip keeps on spinning > new variants of old SoCs, to accommodate the changing DDR landscape > and market. So perhaps they also accept larger RAM sizes? No, in fact we address 256 M Bytes max on sam9x60 and sam9x75 as well. Regards, Nicolas