On Fri, 25 Feb 2011, Pratheesh Gangadhar wrote:

+static irqreturn_t pruss_handler(int irq, struct uio_info *dev_info)
+{
+	void __iomem *base = dev_info->mem[0].internal_addr;
+	void __iomem *intren_reg = base + PINTC_HIER;
+	void __iomem *intrstat_reg = base + PINTC_HIPIR + ((irq - 1) << 2);
+	int val = ioread32(intren_reg), intr_mask = (1 << (irq - 1));
+
+	/* Is interrupt enabled and active ? */
+	if (!(val & intr_mask) && (ioread32(intrstat_reg) & HIPIR_NOPEND))
+		return IRQ_NONE;
+
+	/* Disable interrupt */
+	iowrite32((val & ~intr_mask), intren_reg);
+	return IRQ_HANDLED;
+}

Hmm, just noticed, that you fiddle with the interrupt enable register
here totally unprotected. So on a SMP system you might haandle two
different interrupts at the same time. That wants locking.

And even on UP, you have a problem as you reenable that thing from
user space which requires a read modify write. Racy as hell.

Please look at the other UIO drivers which have the same problem.
Sorry for not noticing earlier!

Thanks,

	tglx