root/arch/x86/kernel/irqinit.c

DEFINITIONS

1. init_ISA_irqs
2. init_IRQ
3. native_init_IRQ

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/linkage.h>
   3 #include <linux/errno.h>
   4 #include <linux/signal.h>
   5 #include <linux/sched.h>
   6 #include <linux/ioport.h>
   7 #include <linux/interrupt.h>
   8 #include <linux/irq.h>
   9 #include <linux/timex.h>
  10 #include <linux/random.h>
  11 #include <linux/kprobes.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel_stat.h>
  14 #include <linux/device.h>
  15 #include <linux/bitops.h>
  16 #include <linux/acpi.h>
  17 #include <linux/io.h>
  18 #include <linux/delay.h>
  19 
  20 #include <linux/atomic.h>
  21 #include <asm/timer.h>
  22 #include <asm/hw_irq.h>
  23 #include <asm/pgtable.h>
  24 #include <asm/desc.h>
  25 #include <asm/apic.h>
  26 #include <asm/setup.h>
  27 #include <asm/i8259.h>
  28 #include <asm/traps.h>
  29 #include <asm/prom.h>
  30 
  31 /*
  32  * ISA PIC or low IO-APIC triggered (INTA-cycle or APIC) interrupts:
  33  * (these are usually mapped to vectors 0x30-0x3f)
  34  */
  35 
  36 /*
  37  * The IO-APIC gives us many more interrupt sources. Most of these
  38  * are unused but an SMP system is supposed to have enough memory ...
  39  * sometimes (mostly wrt. hw bugs) we get corrupted vectors all
  40  * across the spectrum, so we really want to be prepared to get all
  41  * of these. Plus, more powerful systems might have more than 64
  42  * IO-APIC registers.
  43  *
  44  * (these are usually mapped into the 0x30-0xff vector range)
  45  */
  46 
  47 /*
  48  * IRQ2 is cascade interrupt to second interrupt controller
  49  */
  50 static struct irqaction irq2 = {
  51         .handler = no_action,
  52         .name = "cascade",
  53         .flags = IRQF_NO_THREAD,
  54 };
  55 
  56 DEFINE_PER_CPU(vector_irq_t, vector_irq) = {
  57         [0 ... NR_VECTORS - 1] = VECTOR_UNUSED,
  58 };
  59 
  60 void __init init_ISA_irqs(void)
  61 {
  62         struct irq_chip *chip = legacy_pic->chip;
  63         int i;
  64 
  65         /*
  66          * Try to set up the through-local-APIC virtual wire mode earlier.
  67          *
  68          * On some 32-bit UP machines, whose APIC has been disabled by BIOS
  69          * and then got re-enabled by "lapic", it hangs at boot time without this.
  70          */
  71         init_bsp_APIC();
  72 
  73         legacy_pic->init(0);
  74 
  75         for (i = 0; i < nr_legacy_irqs(); i++)
  76                 irq_set_chip_and_handler(i, chip, handle_level_irq);
  77 }
  78 
  79 void __init init_IRQ(void)
  80 {
  81         int i;
  82 
  83         /*
  84          * On cpu 0, Assign ISA_IRQ_VECTOR(irq) to IRQ 0..15.
  85          * If these IRQ's are handled by legacy interrupt-controllers like PIC,
  86          * then this configuration will likely be static after the boot. If
  87          * these IRQ's are handled by more mordern controllers like IO-APIC,
  88          * then this vector space can be freed and re-used dynamically as the
  89          * irq's migrate etc.
  90          */
  91         for (i = 0; i < nr_legacy_irqs(); i++)
  92                 per_cpu(vector_irq, 0)[ISA_IRQ_VECTOR(i)] = irq_to_desc(i);
  93 
  94         BUG_ON(irq_init_percpu_irqstack(smp_processor_id()));
  95 
  96         x86_init.irqs.intr_init();
  97 }
  98 
  99 void __init native_init_IRQ(void)
 100 {
 101         /* Execute any quirks before the call gates are initialised: */
 102         x86_init.irqs.pre_vector_init();
 103 
 104         idt_setup_apic_and_irq_gates();
 105         lapic_assign_system_vectors();
 106 
 107         if (!acpi_ioapic && !of_ioapic && nr_legacy_irqs())
 108                 setup_irq(2, &irq2);
 109 }