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Commit 5711fe90 authored by Jeremy Kerr's avatar Jeremy Kerr
Browse files

[POWERPC] cell: Fix lost interrupts due to fasteoi handler 



We may currently lose interrupts during SPE context switch, as we alter
the INT_Route register. Because the IIC uses a per-thread priority
status, changing the interrupt routing to a different thread means that
the IRQ is no longer masked by the priority status, so we end up with
two fasteoi IRQ handlers executing for the one irq_desc. The fasteoi
handler doesn't handle multiple IRQs, so drops the second one.

Fix this by using our own flow handler. This is based on
handle_edge_irq, but issues an eoi after IRQs are handled, and doesn't
do any mask/unmasking.

Signed-off-by: default avatarJeremy Kerr <jk@ozlabs.org>
parent 3b575064

arch/powerpc/platforms/cell/interrupt.c

+51 −2
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#include <linux/percpu.h>

#include <linux/types.h>

#include <linux/ioport.h>

#include <linux/kernel_stat.h>



#include <asm/io.h>

#include <asm/pgtable.h>
@@ -231,6 +232,54 @@ static int iic_host_match(struct irq_host *h, struct device_node *node) 
				    "IBM,CBEA-Internal-Interrupt-Controller");

}



extern int noirqdebug;



static void handle_iic_irq(unsigned int irq, struct irq_desc *desc)

{

	const unsigned int cpu = smp_processor_id();



	spin_lock(&desc->lock);



	desc->status &= ~(IRQ_REPLAY | IRQ_WAITING);



	/*

	 * If we're currently running this IRQ, or its disabled,

	 * we shouldn't process the IRQ. Mark it pending, handle

	 * the necessary masking and go out

	 */

	if (unlikely((desc->status & (IRQ_INPROGRESS | IRQ_DISABLED)) ||

		    !desc->action)) {

		desc->status |= IRQ_PENDING;

		goto out_eoi;

	}



	kstat_cpu(cpu).irqs[irq]++;



	/* Mark the IRQ currently in progress.*/

	desc->status |= IRQ_INPROGRESS;



	do {

		struct irqaction *action = desc->action;

		irqreturn_t action_ret;



		if (unlikely(!action))

			goto out_eoi;



		desc->status &= ~IRQ_PENDING;

		spin_unlock(&desc->lock);

		action_ret = handle_IRQ_event(irq, action);

		if (!noirqdebug)

			note_interrupt(irq, desc, action_ret);

		spin_lock(&desc->lock);



	} while ((desc->status & (IRQ_PENDING | IRQ_DISABLED)) == IRQ_PENDING);



	desc->status &= ~IRQ_INPROGRESS;

out_eoi:

	desc->chip->eoi(irq);

	spin_unlock(&desc->lock);

}



static int iic_host_map(struct irq_host *h, unsigned int virq,

			irq_hw_number_t hw)

{
@@ -240,10 +289,10 @@ static int iic_host_map(struct irq_host *h, unsigned int virq, 
		break;

	case IIC_IRQ_TYPE_IOEXC:

		set_irq_chip_and_handler(virq, &iic_ioexc_chip,

					 handle_fasteoi_irq);

					 handle_iic_irq);

		break;

	default:

		set_irq_chip_and_handler(virq, &iic_chip, handle_fasteoi_irq);

		set_irq_chip_and_handler(virq, &iic_chip, handle_iic_irq);

	}

	return 0;

}