x86/idt: Simplify the idt_setup_apic_and_irq_gates()

The idt_setup_apic_and_irq_gates() sets the gates from
FIRST_EXTERNAL_VECTOR up to FIRST_SYSTEM_VECTOR first. then secondly, from
FIRST_SYSTEM_VECTOR to NR_VECTORS, it takes both APIC=y and APIC=n into
account.

But for APIC=n, the FIRST_SYSTEM_VECTOR is equal to NR_VECTORS, all
vectors has been set at the first step.

Simplify the second step, make it just work for APIC=y.

Signed-off-by: Dou Liyang <douly.fnst@cn.fujitsu.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20180523023555.2933-1-douly.fnst@cn.fujitsu.com

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 2c3a1b4..74383a3 100644 (file)
--- a/arch/x86/kernel/idt.c
+++ b/arch/x86/kernel/idt.c
@@ -317,15 +317,12 @@ void __init idt_setup_apic_and_irq_gates(void)
                set_intr_gate(i, entry);
        }
 
-       for_each_clear_bit_from(i, system_vectors, NR_VECTORS) {
 #ifdef CONFIG_X86_LOCAL_APIC
+       for_each_clear_bit_from(i, system_vectors, NR_VECTORS) {
                set_bit(i, system_vectors);
                set_intr_gate(i, spurious_interrupt);
-#else
-               entry = irq_entries_start + 8 * (i - FIRST_EXTERNAL_VECTOR);
-               set_intr_gate(i, entry);
-#endif
        }
+#endif
 }
 
 /**