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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF88AC5ACAE for ; Wed, 11 Sep 2019 14:35:48 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 9170D20872 for ; Wed, 11 Sep 2019 14:35:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="aGwL7YM+" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9170D20872 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=R+olGdzPMsEINDxs4OobgvPHnxnKrZNQxplYFAqkQLM=; b=aGwL7YM+5Ly9Kz AHF+Oa73z0u8+w1nb38JALTgzFXUvDelyOXj0rNXsF7llzP+/7rRnuhBX3wGZyhw8hrgFHu9V2yfd GtLhMJgwdC3UlMfLOjMTSfNjVPkguITKi20wNQHJeWeK5+EdII5g8LnMtBBiOG0s1ifbEgGiDD1E4 lZuU+Z9Z+rrrrmLUdjwZvYugKyiZzy4yWlhOEo4gK8Jjqy7bJoAypbUwVjZQJ6D9FF8wkGTcOWGoC dbyjHLOXyoErNTa5igv9LWwDUcJxb858/a03KsTX6/CuWzqzbMqtHlrFZiF/Hj4LyK9TrL2P6yWvw NRy4ALN7ld7Ztdxd9RAA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1i83ie-0008SY-BF; Wed, 11 Sep 2019 14:35:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1i83ib-0008Rl-8u; Wed, 11 Sep 2019 14:35:38 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 0980D1000; Wed, 11 Sep 2019 07:35:34 -0700 (PDT) Received: from C02TF0J2HF1T.local (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5DC9C3F67D; Wed, 11 Sep 2019 07:35:30 -0700 (PDT) Date: Wed, 11 Sep 2019 15:35:27 +0100 From: Catalin Marinas To: Nicolas Saenz Julienne Subject: Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32 Message-ID: <20190911143527.GB43864@C02TF0J2HF1T.local> References: <20190909095807.18709-1-nsaenzjulienne@suse.de> <20190909095807.18709-4-nsaenzjulienne@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190911_073537_358803_1452EE77 X-CRM114-Status: GOOD ( 12.11 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: f.fainelli@gmail.com, mbrugger@suse.com, marc.zyngier@arm.com, robin.murphy@arm.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, robh+dt@kernel.org, wahrenst@gmx.net, m.szyprowski@samsung.com, linux-riscv@lists.infradead.org, phill@raspberrypi.org, Will Deacon , hch@lst.de, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, Sep 11, 2019 at 12:54:38PM +0200, Nicolas Saenz Julienne wrote: > On Mon, 2019-09-09 at 11:58 +0200, Nicolas Saenz Julienne wrote: > > /* > > - * Return the maximum physical address for ZONE_DMA32 (DMA_BIT_MASK(32)). It > > - * currently assumes that for memory starting above 4G, 32-bit devices will > > - * use a DMA offset. > > + * Return the maximum physical address for a zone with a given address size > > + * limit. It currently assumes that for memory starting above 4G, 32-bit > > + * devices will use a DMA offset. > > */ > > -static phys_addr_t __init max_zone_dma32_phys(void) > > +static phys_addr_t __init max_zone_phys(unsigned int zone_bits) > > { > > phys_addr_t offset = memblock_start_of_DRAM() & GENMASK_ULL(63, 32); > > - return min(offset + (1ULL << 32), memblock_end_of_DRAM()); > > + return min(offset + (1ULL << zone_bits), memblock_end_of_DRAM()); > > } > > while testing other code on top of this series on odd arm64 machines I found an > issue: when memblock_start_of_DRAM() != 0, max_zone_phys() isn't taking into > account the offset to the beginning of memory. This doesn't matter with > zone_bits == 32 but it does when zone_bits == 30. I thought about this but I confused myself and the only case I had in mind was an AMD Seattle system with RAM starting at 4GB. What we need from this function is that the lowest naturally aligned 2^30 RAM is covered by ZONE_DMA while the rest to 2^32 are ZONE_DMA32. This assumed that devices only capable of 30-bit (or 32-bit), have the top address bits hardwired to be able access the bottom of the memory (and this would be expressed in DT as the DMA offset). I guess the fix here is to use GENMASK_ULL(63, zone_bits). -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel