From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755307AbdLLNBV (ORCPT ); Tue, 12 Dec 2017 08:01:21 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:34832 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755276AbdLLNBP (ORCPT ); Tue, 12 Dec 2017 08:01:15 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexey Kardashevskiy , Gavin Shan , Michael Ellerman , Sasha Levin Subject: [PATCH 4.9 114/148] powerpc/powernv/ioda2: Gracefully fail if too many TCE levels requested Date: Tue, 12 Dec 2017 13:45:24 +0100 Message-Id: <20171212124437.281858494@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171212124431.207182779@linuxfoundation.org> References: <20171212124431.207182779@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexey Kardashevskiy [ Upstream commit 7aafac11e308d37ed3c509829bb43d80c1811ac3 ] The IODA2 specification says that a 64 DMA address cannot use top 4 bits (3 are reserved and one is a "TVE select"); bottom page_shift bits cannot be used for multilevel table addressing either. The existing IODA2 table allocation code aligns the minimum TCE table size to PAGE_SIZE so in the case of 64K system pages and 4K IOMMU pages, we have 64-4-12=48 bits. Since 64K page stores 8192 TCEs, i.e. needs 13 bits, the maximum number of levels is 48/13 = 3 so we physically cannot address more and EEH happens on DMA accesses. This adds a check that too many levels were requested. It is still possible to have 5 levels in the case of 4K system page size. Signed-off-by: Alexey Kardashevskiy Acked-by: Gavin Shan Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- arch/powerpc/platforms/powernv/pci-ioda.c | 3 +++ 1 file changed, 3 insertions(+) --- a/arch/powerpc/platforms/powernv/pci-ioda.c +++ b/arch/powerpc/platforms/powernv/pci-ioda.c @@ -2623,6 +2623,9 @@ static long pnv_pci_ioda2_table_alloc_pa level_shift = entries_shift + 3; level_shift = max_t(unsigned, level_shift, PAGE_SHIFT); + if ((level_shift - 3) * levels + page_shift >= 60) + return -EINVAL; + /* Allocate TCE table */ addr = pnv_pci_ioda2_table_do_alloc_pages(nid, level_shift, levels, tce_table_size, &offset, &total_allocated);