iommu/exynos: Change error handling when page table update is failed

This patch changes not to panic on any error when updating page table.
Instead prints error messages with callstack.

Signed-off-by: Cho KyongHo <pullip.cho@samsung.com>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@samsung.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 8d7c3f9632f8b55870021d6565288dc9c743d8e9..aec7fd75f400bdf7d63cb62f8a411d93a6bf67bc 100644 (file)
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -728,13 +728,18 @@ finish:
 static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
                                        short *pgcounter)
 {
+       if (lv1ent_section(sent)) {
+               WARN(1, "Trying mapping on %#08lx mapped with 1MiB page", iova);
+               return ERR_PTR(-EADDRINUSE);
+       }
+
        if (lv1ent_fault(sent)) {
                unsigned long *pent;
 
                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(virt_to_phys(pent));
                *pgcounter = NUM_LV2ENTRIES;
@@ -745,14 +750,21 @@ static unsigned long *alloc_lv2entry(unsigned long *sent, unsigned long iova,
        return page_entry(sent, iova);
 }
 
-static int lv1set_section(unsigned long *sent, phys_addr_t paddr, short *pgcnt)
+static int lv1set_section(unsigned long *sent, unsigned long iova,
+                         phys_addr_t paddr, short *pgcnt)
 {
-       if (lv1ent_section(sent))
+       if (lv1ent_section(sent)) {
+               WARN(1, "Trying mapping on 1MiB@%#08lx that is mapped",
+                       iova);
                return -EADDRINUSE;
+       }
 
        if (lv1ent_page(sent)) {
-               if (*pgcnt != NUM_LV2ENTRIES)
+               if (*pgcnt != NUM_LV2ENTRIES) {
+                       WARN(1, "Trying mapping on 1MiB@%#08lx that is mapped",
+                               iova);
                        return -EADDRINUSE;
+               }
 
                kfree(page_entry(sent, 0));
 
@@ -770,8 +782,10 @@ static int lv2set_page(unsigned long *pent, phys_addr_t paddr, size_t size,
                                                                short *pgcnt)
 {
        if (size == SPAGE_SIZE) {
-               if (!lv2ent_fault(pent))
+               if (!lv2ent_fault(pent)) {
+                       WARN(1, "Trying mapping on 4KiB where mapping exists");
                        return -EADDRINUSE;
+               }
 
                *pent = mk_lv2ent_spage(paddr);
                pgtable_flush(pent, pent + 1);
@@ -780,7 +794,10 @@ 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);
+                               WARN(1,
+                               "Trying mapping on 64KiB where mapping exists");
+                               if (i > 0)
+                                       memset(pent - i, 0, sizeof(*pent) * i);
                                return -EADDRINUSE;
                        }
 
@@ -808,7 +825,7 @@ static int exynos_iommu_map(struct iommu_domain *domain, unsigned long iova,
        entry = section_entry(priv->pgtable, iova);
 
        if (size == SECT_SIZE) {
-               ret = lv1set_section(entry, paddr,
+               ret = lv1set_section(entry, iova, paddr,
                                        &priv->lv2entcnt[lv1ent_offset(iova)]);
        } else {
                unsigned long *pent;
@@ -816,17 +833,16 @@ 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) {
+       if (ret)
                pr_debug("%s: Failed to map iova 0x%lx/0x%x bytes\n",
                                                        __func__, iova, size);
-       }
 
        spin_unlock_irqrestore(&priv->pgtablelock, flags);
 
@@ -840,6 +856,7 @@ 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);
 
@@ -848,7 +865,10 @@ 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 (size < SECT_SIZE) {
+                       err_pgsize = SECT_SIZE;
+                       goto err;
+               }
 
                *ent = 0;
                pgtable_flush(ent, ent + 1);
@@ -879,7 +899,10 @@ static size_t exynos_iommu_unmap(struct iommu_domain *domain,
        }
 
        /* lv1ent_large(ent) == true here */
-       BUG_ON(size < LPAGE_SIZE);
+       if (size < LPAGE_SIZE) {
+               err_pgsize = LPAGE_SIZE;
+               goto err;
+       }
 
        memset(ent, 0, sizeof(*ent) * SPAGES_PER_LPAGE);
 
@@ -893,8 +916,15 @@ done:
                sysmmu_tlb_invalidate_entry(data->dev, iova);
        spin_unlock_irqrestore(&priv->lock, flags);
 
-
        return size;
+err:
+       spin_unlock_irqrestore(&priv->pgtablelock, flags);
+
+       WARN(1,
+       "%s: Failed due to size(%#x) @ %#08lx 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,