1 files changed, 18 insertions, 17 deletions

diff --git a/arch/powerpc/sysdev/fsl_rio.c b/arch/powerpc/sysdev/fsl_rio.c
index 5b206a2fe17c..b3fd081d56f5 100644
--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c
@@ -283,23 +283,24 @@ static void __iomem *rio_regs_win;
 #ifdef CONFIG_E500
 int fsl_rio_mcheck_exception(struct pt_regs *regs)
 {
-        const struct exception_table_entry *entry = NULL;
-        unsigned long reason = mfspr(SPRN_MCSR);
-
-        if (reason & MCSR_BUS_RBERR) {
-                reason = in_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR));
-                if (reason & (RIO_LTLEDCSR_IER | RIO_LTLEDCSR_PRT)) {
-                        /* Check if we are prepared to handle this fault */
-                        entry = search_exception_tables(regs->nip);
-                        if (entry) {
-                                pr_debug("RIO: %s - MC Exception handled\n",
-                                         __func__);
-                                out_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR),
-                                         0);
-                                regs->msr |= MSR_RI;
-                                regs->nip = entry->fixup;
-                                return 1;
-                        }
+        const struct exception_table_entry *entry;
+        unsigned long reason;
+
+        if (!rio_regs_win)
+                return 0;
+
+        reason = in_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR));
+        if (reason & (RIO_LTLEDCSR_IER | RIO_LTLEDCSR_PRT)) {
+                /* Check if we are prepared to handle this fault */
+                entry = search_exception_tables(regs->nip);
+                if (entry) {
+                        pr_debug("RIO: %s - MC Exception handled\n",
+                                 __func__);
+                        out_be32((u32 *)(rio_regs_win + RIO_LTLEDCSR),
+                                 0);
+                        regs->msr |= MSR_RI;
+                        regs->nip = entry->fixup;
+                        return 1;
                 }
         }