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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: 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>
This commit is contained in:
Will Deacon 2012-04-05 19:42:10 +01:00 committed by Russell King
parent dff2aa7af8
commit 34af657916
1 changed files with 4 additions and 5 deletions
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9
arch/arm/common/vic.c
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@ -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;
}