From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e24smtp02.br.ibm.com (e24smtp02.br.ibm.com [32.104.18.86]) (using TLSv1 with cipher CAMELLIA256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id DF7A31A0D56 for ; Wed, 20 Jan 2016 07:18:32 +1100 (AEDT) Received: from localhost by e24smtp02.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 19 Jan 2016 18:18:29 -0200 Received: from d24relay03.br.ibm.com (d24relay03.br.ibm.com [9.13.184.25]) by d24dlp02.br.ibm.com (Postfix) with ESMTP id 196B41DC0074 for ; Tue, 19 Jan 2016 15:18:21 -0500 (EST) Received: from d24av01.br.ibm.com (d24av01.br.ibm.com [9.8.31.91]) by d24relay03.br.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u0JKGDNI2097640 for ; Tue, 19 Jan 2016 18:16:13 -0200 Received: from d24av01.br.ibm.com (localhost [127.0.0.1]) by d24av01.br.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u0JKIO29000575 for ; Tue, 19 Jan 2016 18:18:24 -0200 From: "Guilherme G. Piccoli" To: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org Cc: gwshan@linux.vnet.ibm.com, benh@kernel.crashing.org, nfont@linux.vnet.ibm.com, paulus@samba.org, "Guilherme G. Piccoli" Subject: [PATCH 2/2] powerpc/pseries: Check if EEH is enabled on DDW mechanism code Date: Tue, 19 Jan 2016 18:18:20 -0200 Message-Id: <1453234700-27593-3-git-send-email-gpiccoli@linux.vnet.ibm.com> In-Reply-To: <1453234700-27593-1-git-send-email-gpiccoli@linux.vnet.ibm.com> References: <1453234700-27593-1-git-send-email-gpiccoli@linux.vnet.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , The Dynamic DMA Window (DDW) mechanism relies on EEH to obtain the configuration address of devices. For example, the functions query_ddw() and create_ddw() make use of eeh_dev struct. So, the dependency is intrinsic - DDW mechanism will fail if EEH is not enabled. Despite this dependency, no check for EEH availability is performed in DDW code. This patch adds a check based on eeh_enabled() function, so if EEH is not enabled before eeh_dev struct use, DDW will fallback to default iommu mechanism and won't fail. One use case for this patch is when we disable EEH globally via kernel command-line ("eeh=off") - without the patch, a device probe can hit a kernel oops because EEH is disabled but DDW will try to use it. Signed-off-by: Guilherme G. Piccoli --- arch/powerpc/platforms/pseries/iommu.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index bd98ce2..1ff55cc 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -1224,8 +1224,10 @@ static int dma_set_mask_pSeriesLP(struct device *dev, u64 dma_mask) pdev = to_pci_dev(dev); - /* only attempt to use a new window if 64-bit DMA is requested */ - if (!disable_ddw && dma_mask == DMA_BIT_MASK(64)) { + /* We should check if EEH is enabled here, since DDW mechanism has + * an intrinsic dependency of EEH config addr information. Also, we + * only attempt to use a new window if 64-bit DMA is requested */ + if (eeh_enabled() && !disable_ddw && dma_mask == DMA_BIT_MASK(64)) { dn = pci_device_to_OF_node(pdev); dev_dbg(dev, "node is %s\n", dn->full_name); -- 2.1.0