[PATCH v13 02/19] iommu/exynos: change error handling when page table update is failed

From: Shaik Ameer Basha
Date: Mon May 12 2014 - 02:21:33 EST


From: Cho KyongHo <pullip.cho@xxxxxxxxxxx>

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@xxxxxxxxxxx>
Signed-off-by: Shaik Ameer Basha <shaik.ameer@xxxxxxxxxxx>
---
drivers/iommu/exynos-iommu.c | 58 ++++++++++++++++++++++++++++++++----------
1 file changed, 44 insertions(+), 14 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index 8d7c3f9..aec7fd7 100644
--- 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,
--
1.7.9.5

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