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=-8.6 required=3.0 tests=DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,T_DKIM_INVALID,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 3D4D4C433F4 for ; Thu, 20 Sep 2018 18:53:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F22532152A for ; Thu, 20 Sep 2018 18:53:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="QQgO6il9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F22532152A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388340AbeIUAiD (ORCPT ); Thu, 20 Sep 2018 20:38:03 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:36876 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727481AbeIUAiC (ORCPT ); Thu, 20 Sep 2018 20:38:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=PEMjccevc3KLUF8d1Q+gICy4TzsoHuAg7/eyEjFAyf4=; b=QQgO6il9GHPmXfL5abqDWx0Er Cf6BFGd1Cu3ppj44w62WVOikGlPWKxpF2TAZs/5mVXotBoBumsC2hHVHcRa2Afzl0UOd255SplfYR FFpAfb1FP+lM3o0nHGAT+94R6xGqOtb2yZcDqawMzqQGvP/aCLi1dmKnZlU0cZdXhSEh+r2Pr4k1d hh/U+T/C5eIp3gxL8wADvP1Tbv1rwD51e85sZAWek9OGj+FiZRTtmzLQziXRG58jLzCtYjVufoDH9 c9xxJw8wOBR5GaoeJ2NNKzscNuGEzV/ia6TsDqssYX2FkiHWKc4JksgP1v7X4zQTZ1+yH9t/aXbjX MgfTa8vEA==; Received: from 089144198037.atnat0007.highway.a1.net ([89.144.198.37] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1g344Z-0001mR-BL; Thu, 20 Sep 2018 18:53:07 +0000 From: Christoph Hellwig To: iommu@lists.linux-foundation.org Cc: Marek Szyprowski , Robin Murphy , Benjamin Herrenschmidt , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH 5/5] dma-direct: always allow dma mask <= physiscal memory size Date: Thu, 20 Sep 2018 20:52:47 +0200 Message-Id: <20180920185247.20037-6-hch@lst.de> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180920185247.20037-1-hch@lst.de> References: <20180920185247.20037-1-hch@lst.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This way an architecture with less than 4G of RAM can support dma_mask smaller than 32-bit without a ZONE_DMA. Apparently that is a common case on powerpc. Signed-off-by: Christoph Hellwig --- kernel/dma/direct.c | 28 ++++++++++++++++------------ 1 file changed, 16 insertions(+), 12 deletions(-) diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c index 64466b7ef67b..d1e103c6b107 100644 --- a/kernel/dma/direct.c +++ b/kernel/dma/direct.c @@ -4,6 +4,7 @@ * * DMA operations that map physical memory directly without using an IOMMU. */ +#include /* for max_pfn */ #include #include #include @@ -283,21 +284,24 @@ int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents, return nents; } +/* + * Because 32-bit DMA masks are so common we expect every architecture to be + * able to satisfy them - either by not supporting more physical memory, or by + * providing a ZONE_DMA32. If neither is the case, the architecture needs to + * use an IOMMU instead of the direct mapping. + */ int dma_direct_supported(struct device *dev, u64 mask) { -#ifdef CONFIG_ZONE_DMA - if (mask < phys_to_dma(dev, DMA_BIT_MASK(ARCH_ZONE_DMA_BITS))) - return 0; -#else - /* - * Because 32-bit DMA masks are so common we expect every architecture - * to be able to satisfy them - either by not supporting more physical - * memory, or by providing a ZONE_DMA32. If neither is the case, the - * architecture needs to use an IOMMU instead of the direct mapping. - */ - if (mask < phys_to_dma(dev, DMA_BIT_MASK(32))) + u64 min_mask; + + if (IS_ENABLED(CONFIG_ZONE_DMA)) + min_mask = DMA_BIT_MASK(ARCH_ZONE_DMA_BITS); + else + min_mask = min_t(u64, DMA_BIT_MASK(32), + (max_pfn - 1) << PAGE_SHIFT); + + if (mask >= phys_to_dma(dev, min_mask)) return 0; -#endif return 1; } -- 2.18.0