From patchwork Thu Jan 17 09:27:17 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Gautam X-Patchwork-Id: 10767807 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DC38514E5 for ; Thu, 17 Jan 2019 09:27:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CB95E2ED23 for ; Thu, 17 Jan 2019 09:27:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BFBD02ED2D; Thu, 17 Jan 2019 09:27:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.7 required=2.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 517BA2ED23 for ; Thu, 17 Jan 2019 09:27:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725965AbfAQJ1f (ORCPT ); Thu, 17 Jan 2019 04:27:35 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:39442 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728288AbfAQJ1f (ORCPT ); Thu, 17 Jan 2019 04:27:35 -0500 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 3B4616086B; Thu, 17 Jan 2019 09:27:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1547717254; bh=tZs6SWM8y2ouZDZJHYAt/F5ewfYTQq42LF1/h2NE1R0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Z0ojQWlkQzAqu10ExLVytq/tYknk8xRF7XCSMgI5WiKbo/d6j0NeYfhp8jC5FREuB VCefbpy/UD4d/78xKnG5y+VCVdM+p1c3+W9vtYgDeSJXT5QGBCqkouubspZh29QXbO TXNJoqoXN5hRr1guDKUCVNtj1Gs450a0eqnc31Io= Received: from blr-ubuntu-41.ap.qualcomm.com (blr-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vivek.gautam@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id 88D2460237; Thu, 17 Jan 2019 09:27:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1547717253; bh=tZs6SWM8y2ouZDZJHYAt/F5ewfYTQq42LF1/h2NE1R0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hUrmlBs8/O6HAi965dwMj1ygTc19w5qtw7NajTmfyU73BsW43Wd1EHBZvDVsp5xle /QXOeYFIi9j3y7XL4iEc2xvEPnBhzYFBGxEByjO0KC63qt6MQ85AGi8O761MJpuOoj Xr10t43G3hAvFYbAnfjXN2LsEhjdNPgpMsecR+/c= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 88D2460237 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=vivek.gautam@codeaurora.org From: Vivek Gautam To: will.deacon@arm.com, robin.murphy@arm.com, joro@8bytes.org, iommu@lists.linux-foundation.org Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, tfiga@chromium.org, Vivek Gautam Subject: [PATCH 1/2] iommu/io-pgtable-arm: Add support for non-coherent page tables Date: Thu, 17 Jan 2019 14:57:17 +0530 Message-Id: <20190117092718.1396-2-vivek.gautam@codeaurora.org> X-Mailer: git-send-email 2.16.1.72.g5be1f00a9a70 In-Reply-To: <20190117092718.1396-1-vivek.gautam@codeaurora.org> References: <20190117092718.1396-1-vivek.gautam@codeaurora.org> Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From Robin's comment [1] about touching TCR configurations - "TBH if we're going to touch the TCR attributes at all then we should probably correct that sloppiness first - there's an occasional argument for using non-cacheable pagetables even on a coherent SMMU if reducing snoop traffic/latency on walks outweighs the cost of cache maintenance on PTE updates, but anyone thinking they can get that by overriding dma-coherent silently gets the worst of both worlds thanks to this current TCR value." We have IO_PGTABLE_QUIRK_NO_DMA quirk present, but we don't force anybody _not_ using dma-coherent smmu to have non-cacheable page table mappings. Having another quirk flag can help in having non-cacheable memory for page tables once and for all. [1] https://lore.kernel.org/patchwork/patch/1020906/ Signed-off-by: Vivek Gautam --- drivers/iommu/io-pgtable-arm.c | 17 ++++++++++++----- drivers/iommu/io-pgtable.h | 6 ++++++ 2 files changed, 18 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 237cacd4a62b..c76919c30f1a 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -780,7 +780,8 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie) struct arm_lpae_io_pgtable *data; if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | IO_PGTABLE_QUIRK_NO_DMA | - IO_PGTABLE_QUIRK_NON_STRICT)) + IO_PGTABLE_QUIRK_NON_STRICT | + IO_PGTABLE_QUIRK_NON_COHERENT)) return NULL; data = arm_lpae_alloc_pgtable(cfg); @@ -788,9 +789,14 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie) return NULL; /* TCR */ - reg = (ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT) | - (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN0_SHIFT) | - (ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN0_SHIFT); + reg = ARM_LPAE_TCR_SH_IS << ARM_LPAE_TCR_SH0_SHIFT; + + if (cfg->quirks & IO_PGTABLE_QUIRK_NON_COHERENT) + reg |= ARM_LPAE_TCR_RGN_NC << ARM_LPAE_TCR_IRGN0_SHIFT | + ARM_LPAE_TCR_RGN_NC << ARM_LPAE_TCR_ORGN0_SHIFT; + else + reg |= ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_IRGN0_SHIFT | + ARM_LPAE_TCR_RGN_WBWA << ARM_LPAE_TCR_ORGN0_SHIFT; switch (ARM_LPAE_GRANULE(data)) { case SZ_4K: @@ -873,7 +879,8 @@ arm_64_lpae_alloc_pgtable_s2(struct io_pgtable_cfg *cfg, void *cookie) /* The NS quirk doesn't apply at stage 2 */ if (cfg->quirks & ~(IO_PGTABLE_QUIRK_NO_DMA | - IO_PGTABLE_QUIRK_NON_STRICT)) + IO_PGTABLE_QUIRK_NON_STRICT | + IO_PGTABLE_QUIRK_NON_COHERENT)) return NULL; data = arm_lpae_alloc_pgtable(cfg); diff --git a/drivers/iommu/io-pgtable.h b/drivers/iommu/io-pgtable.h index 47d5ae559329..46604cf7b017 100644 --- a/drivers/iommu/io-pgtable.h +++ b/drivers/iommu/io-pgtable.h @@ -75,6 +75,11 @@ struct io_pgtable_cfg { * IO_PGTABLE_QUIRK_NON_STRICT: Skip issuing synchronous leaf TLBIs * on unmap, for DMA domains using the flush queue mechanism for * delayed invalidation. + * + * IO_PGTABLE_QUIRK_NON_COHERENT: Enforce non-cacheable mappings for + * pagetables even on a coherent SMMU for cases where reducing + * snoop traffic/latency on walks outweighs the cost of cache + * maintenance on PTE updates. */ #define IO_PGTABLE_QUIRK_ARM_NS BIT(0) #define IO_PGTABLE_QUIRK_NO_PERMS BIT(1) @@ -82,6 +87,7 @@ struct io_pgtable_cfg { #define IO_PGTABLE_QUIRK_ARM_MTK_4GB BIT(3) #define IO_PGTABLE_QUIRK_NO_DMA BIT(4) #define IO_PGTABLE_QUIRK_NON_STRICT BIT(5) + #define IO_PGTABLE_QUIRK_NON_COHERENT BIT(6) unsigned long quirks; unsigned long pgsize_bitmap; unsigned int ias;