Commit 9a98bc2c authored by Thomas Gleixner's avatar Thomas Gleixner
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x86/vector: Add a sanity check to prevent IRQ2 allocations 



To prevent another incidental removal of the IRQ2 ignore logic in the
IO/APIC code going unnoticed add a sanity check. Add some commentry at the
other place which ignores IRQ2 while at it.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210318192819.795280387@linutronix.de
parent a5e13c6d

arch/x86/kernel/apic/vector.c

+13 −0
Original line number Diff line number Diff line
@@ -543,6 +543,14 @@ static int x86_vector_alloc_irqs(struct irq_domain *domain, unsigned int virq, 
	if ((info->flags & X86_IRQ_ALLOC_CONTIGUOUS_VECTORS) && nr_irqs > 1)

		return -ENOSYS;



	/*

	 * Catch any attempt to touch the cascade interrupt on a PIC

	 * equipped system.

	 */

	if (WARN_ON_ONCE(info->flags & X86_IRQ_ALLOC_LEGACY &&

			 virq == PIC_CASCADE_IR))

		return -EINVAL;



	for (i = 0; i < nr_irqs; i++) {

		irqd = irq_domain_get_irq_data(domain, virq + i);

		BUG_ON(!irqd);
@@ -745,6 +753,11 @@ void __init lapic_assign_system_vectors(void) 


	/* Mark the preallocated legacy interrupts */

	for (i = 0; i < nr_legacy_irqs(); i++) {

		/*

		 * Don't touch the cascade interrupt. It's unusable

		 * on PIC equipped machines. See the large comment

		 * in the IO/APIC code.

		 */

		if (i != PIC_CASCADE_IR)

			irq_matrix_assign(vector_matrix, ISA_IRQ_VECTOR(i));

	}