3 files changed, 36 insertions, 10 deletions

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 18b0d99bd4d6..81837b0710a9 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1599,21 +1599,46 @@ static void __init free_on_init_error(void)
 #endif
 }
 
+/* SB IOAPIC is always on this device in AMD systems */
+#define IOAPIC_SB_DEVID         ((0x00 << 8) | PCI_DEVFN(0x14, 0))
+
 static bool __init check_ioapic_information(void)
 {
+        bool ret, has_sb_ioapic;
         int idx;
 
-        for (idx = 0; idx < nr_ioapics; idx++) {
-                int id = mpc_ioapic_id(idx);
+        has_sb_ioapic = false;
+        ret           = false;
 
-                if (get_ioapic_devid(id) < 0) {
-                        pr_err(FW_BUG "AMD-Vi: IO-APIC[%d] not in IVRS table\n", id);
-                        pr_err("AMD-Vi: Disabling interrupt remapping due to BIOS Bug\n");
-                        return false;
+        for (idx = 0; idx < nr_ioapics; idx++) {
+                int devid, id = mpc_ioapic_id(idx);
+
+                devid = get_ioapic_devid(id);
+                if (devid < 0) {
+                        pr_err(FW_BUG "AMD-Vi: IOAPIC[%d] not in IVRS table\n", id);
+                        ret = false;
+                } else if (devid == IOAPIC_SB_DEVID) {
+                        has_sb_ioapic = true;
+                        ret           = true;
                 }
         }
 
-        return true;
+        if (!has_sb_ioapic) {
+                /*
+                 * We expect the SB IOAPIC to be listed in the IVRS
+                 * table. The system timer is connected to the SB IOAPIC
+                 * and if we don't have it in the list the system will
+                 * panic at boot time.  This situation usually happens
+                 * when the BIOS is buggy and provides us the wrong
+                 * device id for the IOAPIC in the system.
+                 */
+                pr_err(FW_BUG "AMD-Vi: No southbridge IOAPIC found in IVRS table\n");
+        }
+
+        if (!ret)
+                pr_err("AMD-Vi: Disabling interrupt remapping due to BIOS Bug(s)\n");
+
+        return ret;
 }
 
 static void __init free_dma_resources(void)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index d4a4cd445cab..0badfa48b32b 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -4108,7 +4108,7 @@ static void swap_pci_ref(struct pci_dev **from, struct pci_dev *to)
 static int intel_iommu_add_device(struct device *dev)
 {
         struct pci_dev *pdev = to_pci_dev(dev);
-        struct pci_dev *bridge, *dma_pdev;
+        struct pci_dev *bridge, *dma_pdev = NULL;
         struct iommu_group *group;
         int ret;
 
@@ -4122,7 +4122,7 @@ static int intel_iommu_add_device(struct device *dev)
                         dma_pdev = pci_get_domain_bus_and_slot(
                                                 pci_domain_nr(pdev->bus),
                                                 bridge->subordinate->number, 0);
-                else
+                if (!dma_pdev)
                         dma_pdev = pci_dev_get(bridge);
         } else
                 dma_pdev = pci_dev_get(pdev);
diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 0b4d62e0c645..c0f7a4266263 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -200,7 +200,7 @@ enum {
 
 #define SMMU_ADDR_TO_PFN(addr)  ((addr) >> 12)
 #define SMMU_ADDR_TO_PDN(addr)  ((addr) >> 22)
-#define SMMU_PDN_TO_ADDR(addr)  ((pdn) << 22)
+#define SMMU_PDN_TO_ADDR(pdn)   ((pdn) << 22)
 
 #define _READABLE       (1 << SMMU_PTB_DATA_ASID_READABLE_SHIFT)
 #define _WRITABLE       (1 << SMMU_PTB_DATA_ASID_WRITABLE_SHIFT)
@@ -1054,6 +1054,7 @@ static int smmu_debugfs_stats_show(struct seq_file *s, void *v)
                         stats[i], val, offs);
         }
         seq_printf(s, "\n");
+        dput(dent);
 
         return 0;
 }