[POWERPC] Improve robustness of the UIC cascade handler

[linux-2.6-omap-h63xx.git] / arch / powerpc / sysdev / uic.c

diff --git a/arch/powerpc/sysdev/uic.c b/arch/powerpc/sysdev/uic.c
index 22c219e448d4f95c46749278950ad5934b4dabf8..47180b3fca5675519591f5f897d03f38dbb1e1cf 100644 (file)
--- a/arch/powerpc/sysdev/uic.c
+++ b/arch/powerpc/sysdev/uic.c
@@ -266,6 +266,9 @@ irqreturn_t uic_cascade(int virq, void *data)
        int subvirq;
 
        msr = mfdcr(uic->dcrbase + UIC_MSR);
+       if (!msr) /* spurious interrupt */
+               return IRQ_HANDLED;
+
        src = 32 - ffs(msr);
 
        subvirq = irq_linear_revmap(uic->irqhost, src);