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authorDavid S. Miller <davem@davemloft.net>2021-03-25 15:31:22 -0700
committerDavid S. Miller <davem@davemloft.net>2021-03-25 15:31:22 -0700
commitefd13b71a3fa31413f8d15342e01d44b60b0a432 (patch)
tree2ed1b299e25538c5a60485a1047507b49d3e0ecf /arch/x86/kernel/apic/io_apic.c
parent84c7f6c33f42a12eb036ebf0f0e3670799304120 (diff)
parent002322402dafd846c424ffa9240a937f49b48c42 (diff)
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/x86/kernel/apic/io_apic.c')
-rw-r--r--arch/x86/kernel/apic/io_apic.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index c3b60c37c728..73ff4dd426a8 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1032,6 +1032,16 @@ static int mp_map_pin_to_irq(u32 gsi, int idx, int ioapic, int pin,
if (idx >= 0 && test_bit(mp_irqs[idx].srcbus, mp_bus_not_pci)) {
irq = mp_irqs[idx].srcbusirq;
legacy = mp_is_legacy_irq(irq);
+ /*
+ * IRQ2 is unusable for historical reasons on systems which
+ * have a legacy PIC. See the comment vs. IRQ2 further down.
+ *
+ * If this gets removed at some point then the related code
+ * in lapic_assign_system_vectors() needs to be adjusted as
+ * well.
+ */
+ if (legacy && irq == PIC_CASCADE_IR)
+ return -EINVAL;
}
mutex_lock(&ioapic_mutex);