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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
5 #include <linux/threads.h>
7 * Linux IRQ vector layout.
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.
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
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 ... INVALIDATE_TLB_VECTOR_START-1 except 204 : device interrupts
22 * Vectors INVALIDATE_TLB_VECTOR_START ... 255 : special interrupts
24 * 64-bit x86 has per CPU IDT tables, 32-bit has one shared IDT table.
26 * This file enumerates the exact layout of them:
29 #define NMI_VECTOR 0x02
30 #define MCE_VECTOR 0x12
33 * IDT vectors usable for external interrupt sources start at 0x20.
34 * (0x80 is the syscall vector, 0x30-0x3f are for ISA)
36 #define FIRST_EXTERNAL_VECTOR 0x20
38 * We start allocating at 0x21 to spread out vectors evenly between
39 * priority levels. (0x80 is the syscall vector)
41 #define VECTOR_OFFSET_START 1
44 * Reserve the lowest usable vector (and hence lowest priority) 0x20 for
45 * triggering cleanup after irq migration. 0x21-0x2f will still be used
46 * for device interrupts.
48 #define IRQ_MOVE_CLEANUP_VECTOR FIRST_EXTERNAL_VECTOR
50 #define IA32_SYSCALL_VECTOR 0x80
53 * Vectors 0x30-0x3f are used for ISA interrupts.
54 * round up to the next 16-vector boundary
56 #define ISA_IRQ_VECTOR(irq) (((FIRST_EXTERNAL_VECTOR + 16) & ~15) + irq)
59 * Special IRQ vectors used by the SMP architecture, 0xf0-0xff
61 * some of the following vectors are 'rare', they are merged
62 * into a single vector (CALL_FUNCTION_VECTOR) to save vector space.
63 * TLB, reschedule and local APIC vectors are performance-critical.
66 #define SPURIOUS_APIC_VECTOR 0xff
70 #if ((SPURIOUS_APIC_VECTOR & 0x0F) != 0x0F)
71 # error SPURIOUS_APIC_VECTOR definition error
74 #define ERROR_APIC_VECTOR 0xfe
75 #define RESCHEDULE_VECTOR 0xfd
76 #define CALL_FUNCTION_VECTOR 0xfc
77 #define CALL_FUNCTION_SINGLE_VECTOR 0xfb
78 #define THERMAL_APIC_VECTOR 0xfa
79 #define THRESHOLD_APIC_VECTOR 0xf9
80 #define REBOOT_VECTOR 0xf8
83 * Generic system vector for platform specific use
85 #define X86_PLATFORM_IPI_VECTOR 0xf7
90 #define IRQ_WORK_VECTOR 0xf6
92 #define UV_BAU_MESSAGE 0xf5
93 #define DEFERRED_ERROR_VECTOR 0xf4
95 /* Vector on which hypervisor callbacks will be delivered */
96 #define HYPERVISOR_CALLBACK_VECTOR 0xf3
98 /* Vector for KVM to deliver posted interrupt IPI */
99 #ifdef CONFIG_HAVE_KVM
100 #define POSTED_INTR_VECTOR 0xf2
101 #define POSTED_INTR_WAKEUP_VECTOR 0xf1
102 #define POSTED_INTR_NESTED_VECTOR 0xf0
105 #define MANAGED_IRQ_SHUTDOWN_VECTOR 0xef
106 #define LOCAL_TIMER_VECTOR 0xee
108 #define NR_VECTORS 256
110 #ifdef CONFIG_X86_LOCAL_APIC
111 #define FIRST_SYSTEM_VECTOR LOCAL_TIMER_VECTOR
113 #define FIRST_SYSTEM_VECTOR NR_VECTORS
119 * Size the maximum number of interrupts.
121 * If the irq_desc[] array has a sparse layout, we can size things
122 * generously - it scales up linearly with the maximum number of CPUs,
123 * and the maximum number of IO-APICs, whichever is higher.
125 * In other cases we size more conservatively, to not create too large
129 #define NR_IRQS_LEGACY 16
131 #define CPU_VECTOR_LIMIT (64 * NR_CPUS)
132 #define IO_APIC_VECTOR_LIMIT (32 * MAX_IO_APICS)
134 #if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_PCI_MSI)
136 (CPU_VECTOR_LIMIT > IO_APIC_VECTOR_LIMIT ? \
137 (NR_VECTORS + CPU_VECTOR_LIMIT) : \
138 (NR_VECTORS + IO_APIC_VECTOR_LIMIT))
139 #elif defined(CONFIG_X86_IO_APIC)
140 #define NR_IRQS (NR_VECTORS + IO_APIC_VECTOR_LIMIT)
141 #elif defined(CONFIG_PCI_MSI)
142 #define NR_IRQS (NR_VECTORS + CPU_VECTOR_LIMIT)
144 #define NR_IRQS NR_IRQS_LEGACY
147 #endif /* _ASM_X86_IRQ_VECTORS_H */