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// SPDX-License-Identifier: GPL-2.0
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/irqdesc.h>
#include <linux/irqnr.h>
#include "internals.h"
void machine_kexec_mask_interrupts(void)
{
struct irq_desc *desc;
unsigned int i;
for_each_irq_desc(i, desc) {
struct irq_chip *chip;
int check_eoi = 1;
chip = irq_desc_get_chip(desc);
genirq/kexec: Prevent redundant IRQ masking by checking state before shutdown During machine kexec, machine_kexec_mask_interrupts() is responsible for disabling or masking all interrupts. While the irq_disable() is only invoked when the interrupt is not yet disabled, it unconditionally invokes the irq_mask() callback for every interrupt descriptor, even when the interrupt is already masked or not even started up yet. A specific issue was observed in the crash kernel flow after unbinding a device (prior to kexec) that used a GPIO as an IRQ source. The warning was triggered by the gpiochip_disable_irq() function, which attempts to clear the FLAG_IRQ_IS_ENABLED flag when FLAG_USED_AS_IRQ was not set. This issue surfaced after commit a8173820f441 ("gpio: gpiolib: Allow GPIO IRQs to lazy disable") introduced lazy disablement for GPIO IRQs. It replaced disable/enable hooks with mask/unmask hooks. Unlike the disable hook, the mask hook doesn't handle already-masked IRQs. When a GPIO-IRQ driver is unbound, the IRQ is released, triggering __irq_disable() and irq_state_set_masked(). A subsequent call to machine_kexec_mask_interrupts() re-invokes chip->irq_mask(). This results in a call chain, including gpiochip_irq_mask() and gpiochip_disable_irq(). Since FLAG_USED_AS_IRQ was cleared earlier, the warning is triggered. Replace the direct invocation of the irq_mask() and irq_disable() callbacks invoking to irq_shutdown(), which handles the cases correct and avoid it all together when the interrupt has never been started up. Signed-off-by: Eliav Farber <farbere@amazon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241204142003.32859-3-farbere@amazon.com
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if (!chip || !irqd_is_started(&desc->irq_data))
continue;
if (IS_ENABLED(CONFIG_GENERIC_IRQ_KEXEC_CLEAR_VM_FORWARD)) {
/*
* First try to remove the active state from an interrupt which is forwarded
* to a VM. If the interrupt is not forwarded, try to EOI the interrupt.
*/
check_eoi = irq_set_irqchip_state(i, IRQCHIP_STATE_ACTIVE, false);
}
if (check_eoi && chip->irq_eoi && irqd_irq_inprogress(&desc->irq_data))
chip->irq_eoi(&desc->irq_data);
genirq/kexec: Prevent redundant IRQ masking by checking state before shutdown During machine kexec, machine_kexec_mask_interrupts() is responsible for disabling or masking all interrupts. While the irq_disable() is only invoked when the interrupt is not yet disabled, it unconditionally invokes the irq_mask() callback for every interrupt descriptor, even when the interrupt is already masked or not even started up yet. A specific issue was observed in the crash kernel flow after unbinding a device (prior to kexec) that used a GPIO as an IRQ source. The warning was triggered by the gpiochip_disable_irq() function, which attempts to clear the FLAG_IRQ_IS_ENABLED flag when FLAG_USED_AS_IRQ was not set. This issue surfaced after commit a8173820f441 ("gpio: gpiolib: Allow GPIO IRQs to lazy disable") introduced lazy disablement for GPIO IRQs. It replaced disable/enable hooks with mask/unmask hooks. Unlike the disable hook, the mask hook doesn't handle already-masked IRQs. When a GPIO-IRQ driver is unbound, the IRQ is released, triggering __irq_disable() and irq_state_set_masked(). A subsequent call to machine_kexec_mask_interrupts() re-invokes chip->irq_mask(). This results in a call chain, including gpiochip_irq_mask() and gpiochip_disable_irq(). Since FLAG_USED_AS_IRQ was cleared earlier, the warning is triggered. Replace the direct invocation of the irq_mask() and irq_disable() callbacks invoking to irq_shutdown(), which handles the cases correct and avoid it all together when the interrupt has never been started up. Signed-off-by: Eliav Farber <farbere@amazon.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/all/20241204142003.32859-3-farbere@amazon.com
2024-12-04 14:20:03 +00:00
irq_shutdown(desc);
}
}