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authorLinus Torvalds <torvalds@linux-foundation.org>2021-04-26 10:00:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2021-04-26 10:00:38 -0700
commit6f78c2a7b7219bc2e455250365f438621e5819d0 (patch)
treed74514981e1f8e0a8b5ae66a702fce1f833715f4
parent87dcebff9262330ceffad8f1732f29fd35feab5a (diff)
parent9a98bc2cf08a095367449b3548c3d9ad4ad2cd20 (diff)
Merge tag 'x86-apic-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 apic update from Thomas Gleixner: "A single commit to make the vector allocation code more resilent against an accidental allocation attempt for IRQ2" * tag 'x86-apic-2021-04-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/vector: Add a sanity check to prevent IRQ2 allocations
-rw-r--r--arch/x86/kernel/apic/vector.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/vector.c b/arch/x86/kernel/apic/vector.c
index 6aa27e08b3e2..6dbdc7c22bb7 100644
--- a/arch/x86/kernel/apic/vector.c
+++ b/arch/x86/kernel/apic/vector.c
@@ -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));
}