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=-1.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 66BE7C49ED6 for ; Wed, 11 Sep 2019 15:00:21 +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 39C152075C for ; Wed, 11 Sep 2019 15:00:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="fpz3gEoR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 39C152075C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de 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-Type:Cc: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: MIME-Version:References:In-Reply-To:Date:To:From:Subject:Message-ID:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=MWDIA7ErzcWI2DwwgWP5TrqXrRWUuCUuyBIQ3XMxGHY=; b=fpz3gEoRJ6CSHalXidi5BNPYn 61UiXSz4vjDvEy4TBiZCVLlvIfLUrOazSFw98vi0QeAp9CpM0nwdQ/OEYTp+ZBQGrxhMcdI+kX0nh S1tcW11fqgGZ2VfAUCGb0+RfPEViPaYUbvKoMOXE+Xn2WEodl6VN4dV+kKcyeUAGLiU6H3ajAwpVU uFZNfnUbQGmJn6sOy4gj6hG/Y6W1fxzOWl1H02Xo6+pEZvWN4cZlyezFHCL7+RFufY7NObPtRyUTx IcgGQpjQxe+pBN2hX5ijQMHypQn2mdRDyL1kVJsCuFcEzK99aEQycBNG/V42cfWAluCn7i5K5+tUT WBohl7Asw==; 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 1i846Q-0003My-Li; Wed, 11 Sep 2019 15:00:14 +0000 Received: from mx2.suse.de ([195.135.220.15] helo=mx1.suse.de) by bombadil.infradead.org with esmtps (Exim 4.92.2 #3 (Red Hat Linux)) id 1i846I-0002J0-HE; Wed, 11 Sep 2019 15:00:08 +0000 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id F3045B81C; Wed, 11 Sep 2019 15:00:02 +0000 (UTC) Message-ID: Subject: Re: [PATCH v5 3/4] arm64: use both ZONE_DMA and ZONE_DMA32 From: Nicolas Saenz Julienne To: Catalin Marinas Date: Wed, 11 Sep 2019 17:00:00 +0200 In-Reply-To: <20190911143527.GB43864@C02TF0J2HF1T.local> References: <20190909095807.18709-1-nsaenzjulienne@suse.de> <20190909095807.18709-4-nsaenzjulienne@suse.de> <20190911143527.GB43864@C02TF0J2HF1T.local> User-Agent: Evolution 3.32.4 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190911_080006_905726_9B56D154 X-CRM114-Status: GOOD ( 17.10 ) 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: multipart/mixed; boundary="===============7605957042783556132==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============7605957042783556132== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-p7TAQdIbBeJ5BGhbbxNM" --=-p7TAQdIbBeJ5BGhbbxNM Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Wed, 2019-09-11 at 15:35 +0100, Catalin Marinas wrote: > 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 devic= es > > > will > > > - * use a DMA offset. > > > + * Return the maximum physical address for a zone with a given addre= ss > > > 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 =3D 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= ()); > > > } > >=20 > > while testing other code on top of this series on odd arm64 machines I = found > > an > > issue: when memblock_start_of_DRAM() !=3D 0, max_zone_phys() isn't taki= ng into > > account the offset to the beginning of memory. This doesn't matter with > > zone_bits =3D=3D 32 but it does when zone_bits =3D=3D 30. >=20 > 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. I found the issue on a Cavium ThunderX2 server. Oddly enough the memory sta= rts at 0x802f0000. > 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). Ok, I was testing a fix I wrote under these assumptions... > I guess the fix here is to use GENMASK_ULL(63, zone_bits). ...but this is way cleaner than my solution. Thanks! Regards, Nicolas --=-p7TAQdIbBeJ5BGhbbxNM Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iQEzBAABCAAdFiEErOkkGDHCg2EbPcGjlfZmHno8x/4FAl15C/AACgkQlfZmHno8 x/5f8ggAsuyzvV52JP8D4F3gMeBcgMlqN3+DQV47QfnPQoZyacvk5k1N3xUfcbNc TnGiLoB3xsPta+yqccbFl2njg+FBjZc2Ja/+Natqxx+ulXxkIsp7eGP+yeWJiiw9 oUApF6wwL6WYXWn0H+ZoYfwjCFqUDGWuCUYP3K8vHSVytsTmYegU/B+9nvncBfmk iF5Ql/Pd/TA0RLKvs2wftE8h889R2JSGWvdVMCIWWtC5qENC2ar2/ITluJ7kTCRX 9Ekkkh3L8fI6/qgPxKEcC8HuzO4aUTFlpWxxnfUMCd83wzWFWUUdOZ+rcaPpTMN2 ih1+8l3//QFXzpY5utTMqIWXxeKMKA== =r2f7 -----END PGP SIGNATURE----- --=-p7TAQdIbBeJ5BGhbbxNM-- --===============7605957042783556132== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============7605957042783556132==--