This commit removes fault handler definition only for exynos-iommu
driver. Instead, always call iommu fault handler when a fault is
generated by a System MMU. Every new iommu_domain will have a default
fault handler and it can be overridden with iommu_set_fault_handler().
The default fault handler also generates debugging messages and kernel
woops.

Signed-off-by: KyongHo Cho <pullip....@samsung.com>
---
 drivers/iommu/exynos-iommu.c | 99 ++++++++++++++++----------------------------
 1 file changed, 36 insertions(+), 63 deletions(-)

diff --git a/drivers/iommu/exynos-iommu.c b/drivers/iommu/exynos-iommu.c
index b96f3b9..ef7dbd1 100644
--- a/drivers/iommu/exynos-iommu.c
+++ b/drivers/iommu/exynos-iommu.c
@@ -124,16 +124,6 @@ enum exynos_sysmmu_inttype {
        SYSMMU_FAULTS_NUM
 };
 
-/*
- * @itype: type of fault.
- * @pgtable_base: the physical address of page table base. This is 0 if @itype
- *                is SYSMMU_BUSERROR.
- * @fault_addr: the device (virtual) address that the System MMU tried to
- *             translated. This is 0 if @itype is SYSMMU_BUSERROR.
- */
-typedef int (*sysmmu_fault_handler_t)(enum exynos_sysmmu_inttype itype,
-                       unsigned long pgtable_base, unsigned long fault_addr);
-
 static unsigned short fault_reg_offset[SYSMMU_FAULTS_NUM] = {
        REG_PAGE_FAULT_ADDR,
        REG_AR_FAULT_ADDR,
@@ -176,7 +166,6 @@ struct sysmmu_drvdata {
        int activations;
        rwlock_t lock;
        struct iommu_domain *domain;
-       sysmmu_fault_handler_t fault_handler;
        unsigned long pgtable;
 };
 
@@ -291,48 +280,23 @@ finish:
        read_unlock_irqrestore(&data->lock, flags);
 }
 
-static void __set_fault_handler(struct sysmmu_drvdata *data,
-                                       sysmmu_fault_handler_t handler)
-{
-       unsigned long flags;
-
-       write_lock_irqsave(&data->lock, flags);
-       data->fault_handler = handler;
-       write_unlock_irqrestore(&data->lock, flags);
-}
-
-void exynos_sysmmu_set_fault_handler(struct device *dev,
-                                       sysmmu_fault_handler_t handler)
-{
-       struct sysmmu_drvdata *data = dev_get_drvdata(dev->archdata.iommu);
-
-       __set_fault_handler(data, handler);
-}
-
-static int default_fault_handler(enum exynos_sysmmu_inttype itype,
-                    unsigned long pgtable_base, unsigned long fault_addr)
+static void __show_fault_information(unsigned long *pgtable, unsigned long 
iova,
+                                    int flags)
 {
        unsigned long *ent;
 
-       if ((itype >= SYSMMU_FAULTS_NUM) || (itype < SYSMMU_PAGEFAULT))
-               itype = SYSMMU_FAULT_UNKNOWN;
-
        pr_err("%s occurred at 0x%lx(Page table base: 0x%lx)\n",
-                       sysmmu_fault_name[itype], fault_addr, pgtable_base);
+                       sysmmu_fault_name[flags], iova, __pa(pgtable));
 
-       ent = section_entry(__va(pgtable_base), fault_addr);
+       ent = section_entry(pgtable, iova);
        pr_err("\tLv1 entry: 0x%lx\n", *ent);
 
        if (lv1ent_page(ent)) {
-               ent = page_entry(ent, fault_addr);
+               ent = page_entry(ent, iova);
                pr_err("\t Lv2 entry: 0x%lx\n", *ent);
        }
 
        pr_err("Generating Kernel OOPS... because it is unrecoverable.\n");
-
-       BUG();
-
-       return 0;
 }
 
 static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
@@ -341,7 +305,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
        struct sysmmu_drvdata *data = dev_id;
        struct resource *irqres;
        struct platform_device *pdev;
-       enum exynos_sysmmu_inttype itype;
+       enum exynos_sysmmu_inttype itype = SYSMMU_FAULT_UNKNOWN;
        unsigned long addr = -1;
 
        int i, ret = -ENOSYS;
@@ -357,9 +321,7 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void *dev_id)
                        break;
        }
 
-       if (i == pdev->num_resources) {
-               itype = SYSMMU_FAULT_UNKNOWN;
-       } else {
+       if (i < pdev->num_resources) {
                itype = (enum exynos_sysmmu_inttype)
                        __ffs(__raw_readl(data->sfrbases[i] + REG_INT_STATUS));
                if (WARN_ON(!((itype >= 0) && (itype < SYSMMU_FAULT_UNKNOWN))))
@@ -370,25 +332,25 @@ static irqreturn_t exynos_sysmmu_irq(int irq, void 
*dev_id)
        }
 
        if (data->domain)
-               ret = report_iommu_fault(data->domain, data->dev,
-                               addr, itype);
-
-       if ((ret == -ENOSYS) && data->fault_handler) {
-               unsigned long base = data->pgtable;
-               if (itype != SYSMMU_FAULT_UNKNOWN)
-                       base = __raw_readl(
-                                       data->sfrbases[i] + REG_PT_BASE_ADDR);
-               ret = data->fault_handler(itype, base, addr);
-       }
-
-       if (!ret && (itype != SYSMMU_FAULT_UNKNOWN))
+               ret = report_iommu_fault(data->domain, data->dev, addr, itype);
+       else
+               __show_fault_information(__va(data->pgtable), itype, addr);
+
+       if (ret == -ENOSYS)
+               pr_err("NO SYSTEM MMU FAULT HANDLER REGISTERED FOR %s\n",
+                                               dev_name(data->dev));
+       else if (ret < 0)
+               pr_err("SYSTEM MMU FAULT HANDLER FOR %s RETURNED ERROR, %d\n",
+                                               dev_name(data->dev), ret);
+       else if (itype != SYSMMU_FAULT_UNKNOWN)
                __raw_writel(1 << itype, data->sfrbases[i] + REG_INT_CLEAR);
        else
-               dev_dbg(data->sysmmu, "(%s) %s is not handled.\n",
-                               data->dbgname, sysmmu_fault_name[itype]);
+               ret = -ENOSYS;
 
-       if (itype != SYSMMU_FAULT_UNKNOWN)
-               sysmmu_unblock(data->sfrbases[i]);
+       if (ret)
+               BUG();
+
+       sysmmu_unblock(data->sfrbases[i]);
 
        read_unlock(&data->lock);
 
@@ -668,8 +630,6 @@ static int exynos_sysmmu_probe(struct platform_device *pdev)
        rwlock_init(&data->lock);
        INIT_LIST_HEAD(&data->node);
 
-       __set_fault_handler(data, &default_fault_handler);
-
        if (dev->parent)
                pm_runtime_enable(dev);
 
@@ -708,6 +668,17 @@ static inline void pgtable_flush(void *vastart, void 
*vaend)
                                virt_to_phys(vaend));
 }
 
+static int exynos_iommu_fault_handler(struct iommu_domain *domain,
+               struct device *dev, unsigned long iova, int flags, void *token)
+{
+       struct exynos_iommu_domain *priv = domain->priv;
+
+       dev_err(dev, "System MMU Generated FAULT!\n\n");
+       __show_fault_information(priv->pgtable, iova, flags);
+
+       return -ENOSYS;
+}
+
 static int exynos_iommu_domain_init(struct iommu_domain *domain)
 {
        struct exynos_iommu_domain *priv;
@@ -736,6 +707,8 @@ static int exynos_iommu_domain_init(struct iommu_domain 
*domain)
        domain->geometry.aperture_end   = ~0UL;
        domain->geometry.force_aperture = true;
 
+       iommu_set_fault_handler(domain, &exynos_iommu_fault_handler, NULL);
+
        domain->priv = priv;
        return 0;
 
-- 
1.8.0


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