iommu/exynos: fix page table maintenance

This prevents allocating lv2 page table for the lv1 page table entry
that already has 1MB page mapping. In addition some BUG_ON() is
changed to WARN_ON().

Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index e3be3e5..6c4ecce 100644 (file)
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -52,11 +52,11 @@
 #define lv2ent_large(pent) ((*(pent) & 3) == 1)
 
 #define section_phys(sent) (*(sent) & SECT_MASK)
-#define section_offs(iova) ((iova) & 0xFFFFF)
+#define section_offs(iova) ((iova) & ~SECT_MASK)
 #define lpage_phys(pent) (*(pent) & LPAGE_MASK)
-#define lpage_offs(iova) ((iova) & 0xFFFF)
+#define lpage_offs(iova) ((iova) & ~LPAGE_MASK)
 #define spage_phys(pent) (*(pent) & SPAGE_MASK)
-#define spage_offs(iova) ((iova) & 0xFFF)
+#define spage_offs(iova) ((iova) & ~SPAGE_MASK)
 
 #define lv1ent_offset(iova) ((iova) >> SECT_ORDER)
 #define lv2ent_offset(iova) (((iova) & 0xFF000) >> SPAGE_ORDER)
@@ -862,12 +862,14 @@ static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
                pent = kzalloc(LV2TABLE_SIZE, GFP_ATOMIC);
                BUG_ON((unsigned long)pent & (LV2TABLE_SIZE - 1));
                if (!pent)
-                       return NULL;
+                       return ERR_PTR(-ENOMEM);
 
                *sent = mk_lv1ent_page(__pa(pent));
                *pgcounter = NUM_LV2ENTRIES;
                pgtable_flush(pent, pent + NUM_LV2ENTRIES);
                pgtable_flush(sent, sent + 1);
+       } else if (lv1ent_section(sent)) {
+               return ERR_PTR(-EADDRINUSE);
        }
 
        return page_entry(sent, iova);
@@ -894,6 +896,12 @@ static int lv1set_section(unsigned long *sent, phys_addr_t paddr, short *pgcnt)
        return 0;
 }
 
+static void clear_page_table(unsigned long *ent, int n)
+{
+       if (n > 0)
+               memset(ent, 0, sizeof(*ent) * n);
+}
+
 static int lv2set_page(unsigned long *pent, phys_addr_t paddr, size_t size,
                                                                short *pgcnt)
 {
@@ -908,7 +916,7 @@ static int lv2set_page(unsigned long *pent, phys_addr_t paddr, size_t size,
                int i;
                for (i = 0; i < SPAGES_PER_LPAGE; i++, pent++) {
                        if (!lv2ent_fault(pent)) {
-                               memset(pent, 0, sizeof(*pent) * i);
+                               clear_page_table(pent - i, i);
                                return -EADDRINUSE;
                        }
 
@@ -944,17 +952,16 @@ static int exynos_iommu_map(struct iommu_domain *domain, unsigned long iova,
                pent = alloc_lv2entry(entry, iova,
                                        &priv->lv2entcnt[lv1ent_offset(iova)]);
 
-               if (!pent)
-                       ret = -ENOMEM;
+               if (IS_ERR(pent))
+                       ret = PTR_ERR(pent);
                else
                        ret = lv2set_page(pent, paddr, size,
                                        &priv->lv2entcnt[lv1ent_offset(iova)]);
        }
 
-       if (ret) {
-               pr_debug("%s: Failed to map iova 0x%lx/0x%x bytes\n",
-                                                       __func__, iova, size);
-       }
+       if (ret)
+               pr_err("%s: Failed(%d) to map 0x%#x bytes @ %#lx\n",
+                       __func__, ret, size, iova);
 
        spin_unlock_irqrestore(&priv->pgtablelock, flags);
 
@@ -968,6 +975,7 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
        struct sysmmu_drvdata *data;
        unsigned long flags;
        unsigned long *ent;
+       size_t err_pgsize;
 
        BUG_ON(priv->pgtable == NULL);
 
@@ -976,7 +984,10 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
        ent = section_entry(priv->pgtable, iova);
 
        if (lv1ent_section(ent)) {
-               BUG_ON(size < SECT_SIZE);
+               if (WARN_ON(size < SECT_SIZE)) {
+                       err_pgsize = SECT_SIZE;
+                       goto err;
+               }
 
                *ent = 0;
                pgtable_flush(ent, ent + 1);
@@ -1008,9 +1019,12 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
        }
 
        /* lv1ent_large(ent) == true here */
-       BUG_ON(size < LPAGE_SIZE);
+       if (WARN_ON(size < LPAGE_SIZE)) {
+               err_pgsize = LPAGE_SIZE;
+               goto err;
+       }
 
-       memset(ent, 0, sizeof(*ent) * SPAGES_PER_LPAGE);
+       clear_page_table(ent, SPAGES_PER_LPAGE);
        pgtable_flush(ent, ent + SPAGES_PER_LPAGE);
 
        size = LPAGE_SIZE;
@@ -1023,8 +1037,16 @@ done:
                sysmmu_tlb_invalidate_entry(data->dev, iova);
        spin_unlock_irqrestore(&priv->lock, flags);
 
-
        return size;
+err:
+       spin_unlock_irqrestore(&priv->pgtablelock, flags);
+
+       pr_err("%s: Failed due to size(%#x) @ %#lx is"\
+               " smaller than page size %#x\n",
+               __func__, size, iova, err_pgsize);
+
+       return 0;
+
 }
 
 static phys_addr_t exynos_iommu_iova_to_phys(struct iommu_domain *domain,