linux/arch/x86/include/asm/irq_vectors.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_X86_IRQ_VECTORS_H
   3#define _ASM_X86_IRQ_VECTORS_H
   4
   5#include <linux/threads.h>
   6/*
   7 * Linux IRQ vector layout.
   8 *
   9 * There are 256 IDT entries (per CPU - each entry is 8 bytes) which can
  10 * be defined by Linux. They are used as a jump table by the CPU when a
  11 * given vector is triggered - by a CPU-external, CPU-internal or
  12 * software-triggered event.
  13 *
  14 * Linux sets the kernel code address each entry jumps to early during
  15 * bootup, and never changes them. This is the general layout of the
  16 * IDT entries:
  17 *
  18 *  Vectors   0 ...  31 : system traps and exceptions - hardcoded events
  19 *  Vectors  32 ... 127 : device interrupts
  20 *  Vector  128         : legacy int80 syscall interface
  21 *  Vectors 129 ... LOCAL_TIMER_VECTOR-1
  22 *  Vectors LOCAL_TIMER_VECTOR ... 255 : special interrupts
  23 *
  24 * 64-bit x86 has per CPU IDT tables, 32-bit has one shared IDT table.
  25 *
  26 * This file enumerates the exact layout of them:
  27 */
  28
  29/* This is used as an interrupt vector when programming the APIC. */
  30#define NMI_VECTOR                      0x02
  31
  32/*
  33 * IDT vectors usable for external interrupt sources start at 0x20.
  34 * (0x80 is the syscall vector, 0x30-0x3f are for ISA)
  35 */
  36#define FIRST_EXTERNAL_VECTOR           0x20
  37
  38/*
  39 * Reserve the lowest usable vector (and hence lowest priority)  0x20 for
  40 * triggering cleanup after irq migration. 0x21-0x2f will still be used
  41 * for device interrupts.
  42 */
  43#define IRQ_MOVE_CLEANUP_VECTOR         FIRST_EXTERNAL_VECTOR
  44
  45#define IA32_SYSCALL_VECTOR             0x80
  46
  47/*
  48 * Vectors 0x30-0x3f are used for ISA interrupts.
  49 *   round up to the next 16-vector boundary
  50 */
  51#define ISA_IRQ_VECTOR(irq)             (((FIRST_EXTERNAL_VECTOR + 16) & ~15) + irq)
  52
  53/*
  54 * Special IRQ vectors used by the SMP architecture, 0xf0-0xff
  55 *
  56 *  some of the following vectors are 'rare', they are merged
  57 *  into a single vector (CALL_FUNCTION_VECTOR) to save vector space.
  58 *  TLB, reschedule and local APIC vectors are performance-critical.
  59 */
  60
  61#define SPURIOUS_APIC_VECTOR            0xff
  62/*
  63 * Sanity check
  64 */
  65#if ((SPURIOUS_APIC_VECTOR & 0x0F) != 0x0F)
  66# error SPURIOUS_APIC_VECTOR definition error
  67#endif
  68
  69#define ERROR_APIC_VECTOR               0xfe
  70#define RESCHEDULE_VECTOR               0xfd
  71#define CALL_FUNCTION_VECTOR            0xfc
  72#define CALL_FUNCTION_SINGLE_VECTOR     0xfb
  73#define THERMAL_APIC_VECTOR             0xfa
  74#define THRESHOLD_APIC_VECTOR           0xf9
  75#define REBOOT_VECTOR                   0xf8
  76
  77/*
  78 * Generic system vector for platform specific use
  79 */
  80#define X86_PLATFORM_IPI_VECTOR         0xf7
  81
  82/*
  83 * IRQ work vector:
  84 */
  85#define IRQ_WORK_VECTOR                 0xf6
  86
  87/* 0xf5 - unused, was UV_BAU_MESSAGE */
  88#define DEFERRED_ERROR_VECTOR           0xf4
  89
  90/* Vector on which hypervisor callbacks will be delivered */
  91#define HYPERVISOR_CALLBACK_VECTOR      0xf3
  92
  93/* Vector for KVM to deliver posted interrupt IPI */
  94#ifdef CONFIG_HAVE_KVM
  95#define POSTED_INTR_VECTOR              0xf2
  96#define POSTED_INTR_WAKEUP_VECTOR       0xf1
  97#define POSTED_INTR_NESTED_VECTOR       0xf0
  98#endif
  99
 100#define MANAGED_IRQ_SHUTDOWN_VECTOR     0xef
 101
 102#if IS_ENABLED(CONFIG_HYPERV)
 103#define HYPERV_REENLIGHTENMENT_VECTOR   0xee
 104#define HYPERV_STIMER0_VECTOR           0xed
 105#endif
 106
 107#define LOCAL_TIMER_VECTOR              0xec
 108
 109#define NR_VECTORS                       256
 110
 111#ifdef CONFIG_X86_LOCAL_APIC
 112#define FIRST_SYSTEM_VECTOR             LOCAL_TIMER_VECTOR
 113#else
 114#define FIRST_SYSTEM_VECTOR             NR_VECTORS
 115#endif
 116
 117#define NR_EXTERNAL_VECTORS             (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR)
 118#define NR_SYSTEM_VECTORS               (NR_VECTORS - FIRST_SYSTEM_VECTOR)
 119
 120/*
 121 * Size the maximum number of interrupts.
 122 *
 123 * If the irq_desc[] array has a sparse layout, we can size things
 124 * generously - it scales up linearly with the maximum number of CPUs,
 125 * and the maximum number of IO-APICs, whichever is higher.
 126 *
 127 * In other cases we size more conservatively, to not create too large
 128 * static arrays.
 129 */
 130
 131#define NR_IRQS_LEGACY                  16
 132
 133#define CPU_VECTOR_LIMIT                (64 * NR_CPUS)
 134#define IO_APIC_VECTOR_LIMIT            (32 * MAX_IO_APICS)
 135
 136#if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_PCI_MSI)
 137#define NR_IRQS                                         \
 138        (CPU_VECTOR_LIMIT > IO_APIC_VECTOR_LIMIT ?      \
 139                (NR_VECTORS + CPU_VECTOR_LIMIT)  :      \
 140                (NR_VECTORS + IO_APIC_VECTOR_LIMIT))
 141#elif defined(CONFIG_X86_IO_APIC)
 142#define NR_IRQS                         (NR_VECTORS + IO_APIC_VECTOR_LIMIT)
 143#elif defined(CONFIG_PCI_MSI)
 144#define NR_IRQS                         (NR_VECTORS + CPU_VECTOR_LIMIT)
 145#else
 146#define NR_IRQS                         NR_IRQS_LEGACY
 147#endif
 148
 149#endif /* _ASM_X86_IRQ_VECTORS_H */
 150
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