x86: don't set up early exception handlers for external interrupts

All of early setup runs with interrupts disabled, so there is no
need to set up early exception handlers for vectors >= 32

This saves some minor text size.
Signed-off-by: NAndi Kleen <ak@suse.de>
Cc: mingo@elte.hu
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

arch/x86/kernel/head64.c

@@ -127,7 +127,7 @@ void __init x86_64_start_kernel(char * real_mode_data)
 	/* Cleanup the over mapped high alias */
 	cleanup_highmap();
 
-	for (i = 0; i < IDT_ENTRIES; i++) {
+	for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) {
 #ifdef CONFIG_EARLY_PRINTK
 		set_intr_gate(i, &early_idt_handlers[i]);
 #else

arch/x86/kernel/head_64.S

@@ -278,10 +278,8 @@ bad_address:
 
 	.globl early_idt_handlers
 early_idt_handlers:
-	early_idt_tramp 0, 63
-	early_idt_tramp 64, 127
-	early_idt_tramp 128, 191
-	early_idt_tramp 192, 255
+	.set maxe, NUM_EXCEPTION_VECTORS-1
+	early_idt_tramp 0, maxe
 #endif
 
 ENTRY(early_idt_handler)

include/asm-x86/segment.h

@@ -191,13 +191,14 @@
 #define SEGMENT_TI_MASK		0x4
 
 #define IDT_ENTRIES 256
+#define NUM_EXCEPTION_VECTORS 32
 #define GDT_SIZE (GDT_ENTRIES * 8)
 #define GDT_ENTRY_TLS_ENTRIES 3
 #define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
 
 #ifdef __KERNEL__
 #ifndef __ASSEMBLY__
-extern const char early_idt_handlers[IDT_ENTRIES][10];
+extern const char early_idt_handlers[NUM_EXCEPTION_VECTORS][10];
 #endif
 #endif