From mboxrd@z Thu Jan 1 00:00:00 1970 From: Will Deacon Subject: Re: [PATCH 1/8] iommu/arm-smmu: fix the assignment of log2size field Date: Mon, 29 Jun 2015 18:05:18 +0100 Message-ID: <20150629170517.GH17474@arm.com> References: <1435307584-9812-1-git-send-email-thunder.leizhen@huawei.com> <1435307584-9812-2-git-send-email-thunder.leizhen@huawei.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1435307584-9812-2-git-send-email-thunder.leizhen-hv44wF8Li93QT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Zhen Lei Cc: "huxinwei-hv44wF8Li93QT0dZR+AlfA@public.gmane.org" , iommu , Zefan Li , Tianhong Ding , linux-arm-kernel List-Id: iommu@lists.linux-foundation.org Hi Zhen Lei, On Fri, Jun 26, 2015 at 09:32:57AM +0100, Zhen Lei wrote: > Add a new local variable to store the value of log2size, so that it will > not be overridden by L1 table size. > > Signed-off-by: Zhen Lei > --- > drivers/iommu/arm-smmu-v3.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c > index f141301..ba7fe2d 100644 > --- a/drivers/iommu/arm-smmu-v3.c > +++ b/drivers/iommu/arm-smmu-v3.c > @@ -2021,19 +2021,19 @@ static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu) > { > void *strtab; > u64 reg; > - u32 size; > + u32 size, log2size; > int ret; > struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg; > > /* Calculate the L1 size, capped to the SIDSIZE */ > - size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3); > - size = min(size, smmu->sid_bits - STRTAB_SPLIT); > - if (size + STRTAB_SPLIT < smmu->sid_bits) > + log2size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3); > + log2size = min(log2size, smmu->sid_bits - STRTAB_SPLIT); > + if (log2size + STRTAB_SPLIT < smmu->sid_bits) I still think this is wrong. LOG2SIZE should correspond to the whole stream-table, not just the first level. How about the (totally untested) patch below, instead? Will --->8 diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c index 8e9ec81ce4bb..1942a45f68b2 100644 --- a/drivers/iommu/arm-smmu-v3.c +++ b/drivers/iommu/arm-smmu-v3.c @@ -2020,21 +2020,23 @@ static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu) { void *strtab; u64 reg; - u32 size; + u32 size, l1size; int ret; struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg; /* Calculate the L1 size, capped to the SIDSIZE */ size = STRTAB_L1_SZ_SHIFT - (ilog2(STRTAB_L1_DESC_DWORDS) + 3); size = min(size, smmu->sid_bits - STRTAB_SPLIT); - if (size + STRTAB_SPLIT < smmu->sid_bits) + cfg->num_l1_ents = 1 << size; + + size += STRTAB_SPLIT; + if (size < smmu->sid_bits) dev_warn(smmu->dev, "2-level strtab only covers %u/%u bits of SID\n", - size + STRTAB_SPLIT, smmu->sid_bits); + size, smmu->sid_bits); - cfg->num_l1_ents = 1 << size; - size = cfg->num_l1_ents * (STRTAB_L1_DESC_DWORDS << 3); - strtab = dma_zalloc_coherent(smmu->dev, size, &cfg->strtab_dma, + l1size = cfg->num_l1_ents * (STRTAB_L1_DESC_DWORDS << 3); + strtab = dma_zalloc_coherent(smmu->dev, l1size, &cfg->strtab_dma, GFP_KERNEL); if (!strtab) { dev_err(smmu->dev, @@ -2055,8 +2057,7 @@ static int arm_smmu_init_strtab_2lvl(struct arm_smmu_device *smmu) ret = arm_smmu_init_l1_strtab(smmu); if (ret) dma_free_coherent(smmu->dev, - cfg->num_l1_ents * - (STRTAB_L1_DESC_DWORDS << 3), + l1size, strtab, cfg->strtab_dma); return ret;