x86: change FIRST_SYSTEM_VECTOR to a variable

The SGI UV system needs several more system vectors than a vanilla
x86_64 system.  Rather than burden the other archs with extra system
vectors that they don't use, change FIRST_SYSTEM_VECTOR to a variable,
so that it can be dynamic.
Signed-off-by: Alan Mayer <ajm@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/apic_32.c

@@ -1351,13 +1351,13 @@ void __init smp_intr_init(void)
 	 * The reschedule interrupt is a CPU-to-CPU reschedule-helper
 	 * IPI, driven by wakeup.
 	 */
-	set_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
+	alloc_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
 
 	/* IPI for invalidation */
-	set_intr_gate(INVALIDATE_TLB_VECTOR, invalidate_interrupt);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR, invalidate_interrupt);
 
 	/* IPI for generic function call */
-	set_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
+	alloc_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
 }
 #endif
 
@@ -1370,15 +1370,15 @@ void __init apic_intr_init(void)
 	smp_intr_init();
 #endif
 	/* self generated IPI for local APIC timer */
-	set_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
+	alloc_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
 
 	/* IPI vectors for APIC spurious and error interrupts */
-	set_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
-	set_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
+	alloc_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
+	alloc_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
 
 	/* thermal monitor LVT interrupt */
 #ifdef CONFIG_X86_MCE_P4THERMAL
-	set_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
+	alloc_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
 #endif
 }
 

arch/x86/kernel/i8259_64.c

@@ -493,33 +493,33 @@ void __init native_init_IRQ(void)
 	 * The reschedule interrupt is a CPU-to-CPU reschedule-helper
 	 * IPI, driven by wakeup.
 	 */
-	set_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
+	alloc_intr_gate(RESCHEDULE_VECTOR, reschedule_interrupt);
 
 	/* IPIs for invalidation */
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+0, invalidate_interrupt0);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+1, invalidate_interrupt1);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+2, invalidate_interrupt2);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+3, invalidate_interrupt3);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+4, invalidate_interrupt4);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+5, invalidate_interrupt5);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+6, invalidate_interrupt6);
-	set_intr_gate(INVALIDATE_TLB_VECTOR_START+7, invalidate_interrupt7);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+0, invalidate_interrupt0);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+1, invalidate_interrupt1);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+2, invalidate_interrupt2);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+3, invalidate_interrupt3);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+4, invalidate_interrupt4);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+5, invalidate_interrupt5);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+6, invalidate_interrupt6);
+	alloc_intr_gate(INVALIDATE_TLB_VECTOR_START+7, invalidate_interrupt7);
 
 	/* IPI for generic function call */
-	set_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
+	alloc_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
 
 	/* Low priority IPI to cleanup after moving an irq */
 	set_intr_gate(IRQ_MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt);
 #endif
-	set_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
-	set_intr_gate(THRESHOLD_APIC_VECTOR, threshold_interrupt);
+	alloc_intr_gate(THERMAL_APIC_VECTOR, thermal_interrupt);
+	alloc_intr_gate(THRESHOLD_APIC_VECTOR, threshold_interrupt);
 
 	/* self generated IPI for local APIC timer */
-	set_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
+	alloc_intr_gate(LOCAL_TIMER_VECTOR, apic_timer_interrupt);
 
 	/* IPI vectors for APIC spurious and error interrupts */
-	set_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
-	set_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
+	alloc_intr_gate(SPURIOUS_APIC_VECTOR, spurious_interrupt);
+	alloc_intr_gate(ERROR_APIC_VECTOR, error_interrupt);
 
 	if (!acpi_ioapic)
 		setup_irq(2, &irq2);

arch/x86/kernel/io_apic_32.c

@@ -83,6 +83,10 @@ int mp_irq_entries;
 
 static int disable_timer_pin_1 __initdata;
 
+int first_system_vector = 0xfe;
+
+char system_vectors[NR_VECTORS] = { [0 ... NR_VECTORS-1] = SYS_VECTOR_FREE};
+
 /*
  * Rough estimation of how many shared IRQs there are, can
  * be changed anytime.
@@ -1176,7 +1180,7 @@ static int __assign_irq_vector(int irq)
 	offset = current_offset;
 next:
 	vector += 8;
-	if (vector >= FIRST_SYSTEM_VECTOR) {
+	if (vector >= first_system_vector) {
 		offset = (offset + 1) % 8;
 		vector = FIRST_DEVICE_VECTOR + offset;
 	}
@@ -2269,7 +2273,7 @@ void __init setup_IO_APIC(void)
 	int i;
 
 	/* Reserve all the system vectors. */
-	for (i = FIRST_SYSTEM_VECTOR; i < NR_VECTORS; i++)
+	for (i = first_system_vector; i < NR_VECTORS; i++)
 		set_bit(i, used_vectors);
 
 	enable_IO_APIC();

arch/x86/kernel/io_apic_64.c

@@ -82,6 +82,10 @@ struct irq_cfg irq_cfg[NR_IRQS] __read_mostly = {
 
 static int assign_irq_vector(int irq, cpumask_t mask);
 
+int first_system_vector = 0xfe;
+
+char system_vectors[NR_VECTORS] = { [0 ... NR_VECTORS-1] = SYS_VECTOR_FREE};
+
 #define __apicdebuginit  __init
 
 int sis_apic_bug; /* not actually supported, dummy for compile */
@@ -730,7 +734,7 @@ static int __assign_irq_vector(int irq, cpumask_t mask)
 		offset = current_offset;
 next:
 		vector += 8;
-		if (vector >= FIRST_SYSTEM_VECTOR) {
+		if (vector >= first_system_vector) {
 			/* If we run out of vectors on large boxen, must share them. */
 			offset = (offset + 1) % 8;
 			vector = FIRST_DEVICE_VECTOR + offset;

include/asm-x86/desc.h

@@ -311,6 +311,28 @@ static inline void set_intr_gate(unsigned int n, void *addr)
 	_set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
 }
 
+#define SYS_VECTOR_FREE		0
+#define SYS_VECTOR_ALLOCED	1
+
+extern int first_system_vector;
+extern char system_vectors[];
+
+static inline void alloc_system_vector(int vector)
+{
+	if (system_vectors[vector] == SYS_VECTOR_FREE) {
+		system_vectors[vector] = SYS_VECTOR_ALLOCED;
+		if (first_system_vector > vector)
+			first_system_vector = vector;
+	} else
+		BUG();
+}
+
+static inline void alloc_intr_gate(unsigned int n, void *addr)
+{
+	alloc_system_vector(n);
+	set_intr_gate(n, addr);
+}
+
 /*
  * This routine sets up an interrupt gate at directory privilege level 3.
  */

include/asm-x86/irq_vectors.h

@@ -96,8 +96,6 @@
 # define FIRST_DEVICE_VECTOR	(IRQ15_VECTOR + 2)
 #endif
 
-#define FIRST_SYSTEM_VECTOR	0xef
-
 #define NR_VECTORS		256
 
 #define FPU_IRQ			13