Re: [PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

Nicolin Chen
2020-09-26T20:52:42Z

Hi Dmitry,

Thank you for the review.

On Sat, Sep 26, 2020 at 05:48:54PM +0300, Dmitry Osipenko wrote:
> 26.09.2020 11:07, Nicolin Chen пишет:
> ...
> > +static int tegra_smmu_mappings_show(struct seq_file *s, void *data)
> > +{
> > + struct tegra_smmu_group_debug *group_debug = s->private;
> > + const struct tegra_smmu_swgroup *group;
> > + struct tegra_smmu_as *as;
> > + struct tegra_smmu *smmu;
> > + int pd_index, pt_index;
> > + u64 pte_count = 0;
> > + u32 pde_count = 0;
> > + u32 val, ptb_reg;
> > + u32 *pd;
> > +
> > + if (!group_debug || !group_debug->priv || !group_debug->group)
> > + return 0;
> > +
> > + group = group_debug->group;
> > + as = group_debug->priv;
> > + smmu = as->smmu;
> > +
> > + val = smmu_readl(smmu, group->reg) & SMMU_ASID_ENABLE;
> > + if (!val)
> > + return 0;
> > +
> > + pd = page_address(as->pd);
> > + if (!pd)
> > + return 0;
> > +
> > + seq_printf(s, "\nSWGROUP: %s\nASID: %d\nreg: 0x%x\n", group->name,
> > + as->id, group->reg);
> > +
> > + mutex_lock(&smmu->lock);
> > + smmu_writel(smmu, as->id & 0x7f, SMMU_PTB_ASID);
> > + ptb_reg = smmu_readl(smmu, SMMU_PTB_DATA);
>
> I think the whole traverse needs a locking protection, doesn't it?

Hmm..probably would be nicer. Will move the mutex to the top.

> > + mutex_unlock(&smmu->lock);
> > +
> > + seq_printf(s, "PTB_ASID: 0x%x\nas->pd_dma: 0x%llx\n", ptb_reg, as->pd_dma);
> > + seq_puts(s, "{\n");
> > +
> > + for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
> > + struct page *pt;
> > + u32 *addr;
> > +
> > + if (!as->count[pd_index] || !pd[pd_index])
> > + continue;
> > +
> > + pde_count++;
> > + pte_count += as->count[pd_index];
> > + seq_printf(s, "\t[%d] 0x%x (%d)\n",
> > + pd_index, pd[pd_index], as->count[pd_index]);
> > + pt = as->pts[pd_index];
> > + addr = page_address(pt);
>
> This needs as->lock protection.

Will add that.

> > + seq_puts(s, "\t{\n");
> > + seq_printf(s, "\t\t%-5s %-4s %12s %12s\n", "PDE", "ATTR", "PHYS", "IOVA");
> > + for (pt_index = 0; pt_index < SMMU_NUM_PTE; pt_index++) {
> > + u64 iova;
> > +
> > + if (!addr[pt_index])
> > + continue;
> > +
> > + iova = ((dma_addr_t)pd_index & (SMMU_NUM_PDE - 1)) << SMMU_PDE_SHIFT;
> > + iova |= ((dma_addr_t)pt_index & (SMMU_NUM_PTE - 1)) << SMMU_PTE_SHIFT;
> > +
> > + seq_printf(s, "\t\t#%-4d 0x%-4x 0x%-12llx 0x%-12llx\n",
> > + pt_index, addr[pt_index] >> SMMU_PTE_ATTR_SHIFT,
> > + SMMU_PFN_PHYS(addr[pt_index] & ~SMMU_PTE_ATTR), iova);
> > + }
> > + seq_puts(s, "\t}\n");
> > + }
> > + seq_puts(s, "}\n");
> > + seq_printf(s, "Total PDE count: %d\n", pde_count);
> > + seq_printf(s, "Total PTE count: %lld\n", pte_count);
> > +
> > + return 0;
> > +}
> > +
> > +DEFINE_SHOW_ATTRIBUTE(tegra_smmu_mappings);
> > +
> > static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu)
> > {
> > + const struct tegra_smmu_soc *soc = smmu->soc;
> > + struct tegra_smmu_group_debug *group_debug;
> > + struct device *dev = smmu->dev;
> > + struct dentry *d;
> > + int i;
> > +
> > + group_debug = devm_kzalloc(dev, sizeof(*group_debug) * soc->num_swgroups, GFP_KERNEL);
>
> devm_kcalloc()

Will change it.

Thanks
Nic