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Commit 34af6579 authored by Will Deacon's avatar Will Deacon Committed by Russell King
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ARM: 7377/1: vic: re-read status register before dispatching each IRQ handler 



handle_IRQ may briefly cause interrupts to be re-enabled during soft IRQ
processing on the exit path, leading to nested handling of VIC interrupts.

Since the current code does not re-read the VIC_IRQ_STATUS register, this
can lead to multiple invocations of the same interrupt handler and
spurious interrupts to be reported.

This patch changes the VIC interrupt dispatching code to re-read the
status register each time, avoiding duplicate invocations of the same
handler.

Acked-and-Tested-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>

Reviewed-by: default avatarJamie Iles <jamie@jamieiles.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent dff2aa7a

arch/arm/common/vic.c

+4 −5
Original line number Original line Diff line number Diff line
@@ -427,19 +427,18 @@ int __init vic_of_init(struct device_node *node, struct device_node *parent) 




/*

/*

 * Handle each interrupt in a single VIC.  Returns non-zero if we've

 * Handle each interrupt in a single VIC.  Returns non-zero if we've

 * handled at least one interrupt.  This does a single read of the

 * handled at least one interrupt.  This reads the status register

 * status register and handles all interrupts in order from LSB first.

 * before handling each interrupt, which is necessary given that

 * handle_IRQ may briefly re-enable interrupts for soft IRQ handling.

 */

 */

static int handle_one_vic(struct vic_device *vic, struct pt_regs *regs)

static int handle_one_vic(struct vic_device *vic, struct pt_regs *regs)

{

{

	u32 stat, irq;

	u32 stat, irq;

	int handled = 0;

	int handled = 0;





	stat = readl_relaxed(vic->base + VIC_IRQ_STATUS);

	while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) {

	while (stat) {

		irq = ffs(stat) - 1;

		irq = ffs(stat) - 1;

		handle_IRQ(irq_find_mapping(vic->domain, irq), regs);

		handle_IRQ(irq_find_mapping(vic->domain, irq), regs);

		stat &= ~(1 << irq);

		handled = 1;

		handled = 1;

	}

	}