[PATCH v2] x86/idt: Simplify the idt_setup_apic_and_irq_gates()

[Dou Liyang]

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@xxxxxxxxxxxxxx>
---
 arch/x86/kernel/idt.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kernel/idt.c b/arch/x86/kernel/idt.c
index 2c3a1b4294eb..74383a3780dc 100644
--- 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
 }
 
 /**
-- 
2.14.3