Merge branch 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-apic-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (25 commits)
  x86: Fix out of order of gsi
  x86: apic: Fix mismerge, add arch_probe_nr_irqs() again
  x86, irq: Keep chip_data in create_irq_nr and destroy_irq
  xen: Remove unnecessary arch specific xen irq functions.
  smp: Use nr_cpus= to set nr_cpu_ids early
  x86, irq: Remove arch_probe_nr_irqs
  sparseirq: Use radix_tree instead of ptrs array
  sparseirq: Change irq_desc_ptrs to static
  init: Move radix_tree_init() early
  irq: Remove unnecessary bootmem code
  x86: Add iMac9,1 to pci_reboot_dmi_table
  x86: Convert i8259_lock to raw_spinlock
  x86: Convert nmi_lock to raw_spinlock
  x86: Convert ioapic_lock and vector_lock to raw_spinlock
  x86: Avoid race condition in pci_enable_msix()
  x86: Fix SCI on IOAPIC != 0
  x86, ia32_aout: do not kill argument mapping
  x86, irq: Move __setup_vector_irq() before the first irq enable in cpu online path
  x86, irq: Update the vector domain for legacy irqs handled by io-apic
  x86, irq: Don't block IRQ0_VECTOR..IRQ15_VECTOR's on all cpu's
  ...

1 files changed, 17 insertions, 18 deletions

diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c
index d5932226614f..fce55d532631 100644
--- a/arch/x86/kernel/irqinit.c
+++ b/arch/x86/kernel/irqinit.c
@@ -84,24 +84,7 @@ static struct irqaction irq2 = {
 };
 
 DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
-	[0 ... IRQ0_VECTOR - 1] = -1,
-	[IRQ0_VECTOR] = 0,
-	[IRQ1_VECTOR] = 1,
-	[IRQ2_VECTOR] = 2,
-	[IRQ3_VECTOR] = 3,
-	[IRQ4_VECTOR] = 4,
-	[IRQ5_VECTOR] = 5,
-	[IRQ6_VECTOR] = 6,
-	[IRQ7_VECTOR] = 7,
-	[IRQ8_VECTOR] = 8,
-	[IRQ9_VECTOR] = 9,
-	[IRQ10_VECTOR] = 10,
-	[IRQ11_VECTOR] = 11,
-	[IRQ12_VECTOR] = 12,
-	[IRQ13_VECTOR] = 13,
-	[IRQ14_VECTOR] = 14,
-	[IRQ15_VECTOR] = 15,
-	[IRQ15_VECTOR + 1 ... NR_VECTORS - 1] = -1
+	[0 ... NR_VECTORS - 1] = -1,
 };
 
 int vector_used_by_percpu_irq(unsigned int vector)
@@ -116,6 +99,9 @@ int vector_used_by_percpu_irq(unsigned int vector)
 	return 0;
 }
 
+/* Number of legacy interrupts */
+int nr_legacy_irqs __read_mostly = NR_IRQS_LEGACY;
+
 void __init init_ISA_irqs(void)
 {
 	int i;
@@ -142,6 +128,19 @@ void __init init_ISA_irqs(void)
 
 void __init init_IRQ(void)
 {
+	int i;
+
+	/*
+	 * On cpu 0, Assign IRQ0_VECTOR..IRQ15_VECTOR's to IRQ 0..15.
+	 * If these IRQ's are handled by legacy interrupt-controllers like PIC,
+	 * then this configuration will likely be static after the boot. If
+	 * these IRQ's are handled by more mordern controllers like IO-APIC,
+	 * then this vector space can be freed and re-used dynamically as the
+	 * irq's migrate etc.
+	 */
+	for (i = 0; i < nr_legacy_irqs; i++)
+		per_cpu(vector_irq, 0)[IRQ0_VECTOR + i] = i;
+
 	x86_init.irqs.intr_init();
 }