ARM: 7377/1: vic: re-read status register before dispatching each IRQ handler (34af6579) · Commits · 戴 / test

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:

H Hartley Sweeten <hsweeten@visionengravers.com> Reviewed-by:

Jamie Iles <jamie@jamieiles.com> Signed-off-by:

Will Deacon <will.deacon@arm.com> Signed-off-by:

Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/common/vic.c

+4 −5

Original line number	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
		* handled at least one interrupt. This does a single read of the
		* status register and handles all interrupts in order from LSB first.
		* handled at least one interrupt. This reads the status register
		* 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)
		{
		u32 stat, irq;
		int handled = 0;

		stat = readl_relaxed(vic->base + VIC_IRQ_STATUS);
		while (stat) {
		while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) {
		irq = ffs(stat) - 1;
		handle_IRQ(irq_find_mapping(vic->domain, irq), regs);
		stat &= ~(1 << irq);
		handled = 1;
		}

Admin message