From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753618AbbBPSib (ORCPT ); Mon, 16 Feb 2015 13:38:31 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:42495 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752015AbbBPSia (ORCPT ); Mon, 16 Feb 2015 13:38:30 -0500 From: Will Deacon To: joro@8bytes.org Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Will Deacon Subject: [PATCH] iommu/io-pgtable-arm: fix self-test WARNs on i386 Date: Mon, 16 Feb 2015 18:38:20 +0000 Message-Id: <1424111900-23887-1-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Various build/boot bots have reported WARNs being triggered by the ARM iopgtable LPAE self-tests on i386 machines. This boils down to two instances of right-shifting a 32-bit unsigned long (i.e. an iova) by more than the size of the type. On 32-bit ARM, this happens to give us zero, hence my testing didn't catch this earlier. This patch fixes the issue by using DIV_ROUND_UP and explicit case to to avoid the erroneous shifts. Reported-by: Fengguang Wu Reported-by: Huang Ying Signed-off-by: Will Deacon --- Joerg -- please can you apply this as a fix for 3.20? drivers/iommu/io-pgtable-arm.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c index 5a500edf00cc..b610a8dee238 100644 --- a/drivers/iommu/io-pgtable-arm.c +++ b/drivers/iommu/io-pgtable-arm.c @@ -56,7 +56,8 @@ ((((d)->levels - ((l) - ARM_LPAE_START_LVL(d) + 1)) \ * (d)->bits_per_level) + (d)->pg_shift) -#define ARM_LPAE_PAGES_PER_PGD(d) ((d)->pgd_size >> (d)->pg_shift) +#define ARM_LPAE_PAGES_PER_PGD(d) \ + DIV_ROUND_UP((d)->pgd_size, 1UL << (d)->pg_shift) /* * Calculate the index at level l used to map virtual address a using the @@ -66,7 +67,7 @@ ((l) == ARM_LPAE_START_LVL(d) ? ilog2(ARM_LPAE_PAGES_PER_PGD(d)) : 0) #define ARM_LPAE_LVL_IDX(a,l,d) \ - (((a) >> ARM_LPAE_LVL_SHIFT(l,d)) & \ + (((u64)(a) >> ARM_LPAE_LVL_SHIFT(l,d)) & \ ((1 << ((d)->bits_per_level + ARM_LPAE_PGD_IDX(l,d))) - 1)) /* Calculate the block/page mapping size at level l for pagetable in d. */ -- 2.1.4