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x86, irq: add IRQ layout comments

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Describe the layout of x86 trap/exception/IRQ vectors and clean
up indentation and other small details.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Ingo Molnar 2009-01-31 02:48:17 +01:00
parent 3e92ab3d7e
commit 9fc2e79d4f
1 changed files with 58 additions and 34 deletions
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92
arch/x86/include/asm/irq_vectors.h
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@ -3,45 +3,69 @@
#include <linux/threads.h>
#define NMI_VECTOR 0x02
/*
* Linux IRQ vector layout.
*
* There are 256 IDT entries (per CPU - each entry is 8 bytes) which can
* be defined by Linux. They are used as a jump table by the CPU when a
* given vector is triggered - by a CPU-external, CPU-internal or
* software-triggered event.
*
* Linux sets the kernel code address each entry jumps to early during
* bootup, and never changes them. This is the general layout of the
* IDT entries:
*
* Vectors 0 ... 31 : system traps and exceptions - hardcoded events
* Vectors 32 ... 127 : device interrupts
* Vector 128 : legacy int80 syscall interface
* Vectors 129 ... 237 : device interrupts
* Vectors 238 ... 255 : special interrupts
*
* 64-bit x86 has per CPU IDT tables, 32-bit has one shared IDT table.
*
* This file enumerates the exact layout of them:
*/
#define NMI_VECTOR 0x02
/*
* IDT vectors usable for external interrupt sources start
* at 0x20:
*/
#define FIRST_EXTERNAL_VECTOR 0x20
#define FIRST_EXTERNAL_VECTOR 0x20
#ifdef CONFIG_X86_32
# define SYSCALL_VECTOR 0x80
# define SYSCALL_VECTOR 0x80
#else
# define IA32_SYSCALL_VECTOR 0x80
# define IA32_SYSCALL_VECTOR 0x80
#endif
/*
* Reserve the lowest usable priority level 0x20 - 0x2f for triggering
* cleanup after irq migration.
*/
#define IRQ_MOVE_CLEANUP_VECTOR FIRST_EXTERNAL_VECTOR
#define IRQ_MOVE_CLEANUP_VECTOR FIRST_EXTERNAL_VECTOR
/*
* Vectors 0x30-0x3f are used for ISA interrupts.
*/
#define IRQ0_VECTOR (FIRST_EXTERNAL_VECTOR + 0x10)
#define IRQ1_VECTOR (IRQ0_VECTOR + 1)
#define IRQ2_VECTOR (IRQ0_VECTOR + 2)
#define IRQ3_VECTOR (IRQ0_VECTOR + 3)
#define IRQ4_VECTOR (IRQ0_VECTOR + 4)
#define IRQ5_VECTOR (IRQ0_VECTOR + 5)
#define IRQ6_VECTOR (IRQ0_VECTOR + 6)
#define IRQ7_VECTOR (IRQ0_VECTOR + 7)
#define IRQ8_VECTOR (IRQ0_VECTOR + 8)
#define IRQ9_VECTOR (IRQ0_VECTOR + 9)
#define IRQ10_VECTOR (IRQ0_VECTOR + 10)
#define IRQ11_VECTOR (IRQ0_VECTOR + 11)
#define IRQ12_VECTOR (IRQ0_VECTOR + 12)
#define IRQ13_VECTOR (IRQ0_VECTOR + 13)
#define IRQ14_VECTOR (IRQ0_VECTOR + 14)
#define IRQ15_VECTOR (IRQ0_VECTOR + 15)
#define IRQ0_VECTOR (FIRST_EXTERNAL_VECTOR + 0x10)
#define IRQ1_VECTOR (IRQ0_VECTOR + 1)
#define IRQ2_VECTOR (IRQ0_VECTOR + 2)
#define IRQ3_VECTOR (IRQ0_VECTOR + 3)
#define IRQ4_VECTOR (IRQ0_VECTOR + 4)
#define IRQ5_VECTOR (IRQ0_VECTOR + 5)
#define IRQ6_VECTOR (IRQ0_VECTOR + 6)
#define IRQ7_VECTOR (IRQ0_VECTOR + 7)
#define IRQ8_VECTOR (IRQ0_VECTOR + 8)
#define IRQ9_VECTOR (IRQ0_VECTOR + 9)
#define IRQ10_VECTOR (IRQ0_VECTOR + 10)
#define IRQ11_VECTOR (IRQ0_VECTOR + 11)
#define IRQ12_VECTOR (IRQ0_VECTOR + 12)
#define IRQ13_VECTOR (IRQ0_VECTOR + 13)
#define IRQ14_VECTOR (IRQ0_VECTOR + 14)
#define IRQ15_VECTOR (IRQ0_VECTOR + 15)
/*
* Special IRQ vectors used by the SMP architecture, 0xf0-0xff
@ -75,36 +99,36 @@
/* f0-f7 used for spreading out TLB flushes: */
#define INVALIDATE_TLB_VECTOR_END 0xf7
#define INVALIDATE_TLB_VECTOR_START 0xf0
#define NUM_INVALIDATE_TLB_VECTORS 8
#define NUM_INVALIDATE_TLB_VECTORS 8
/*
* Local APIC timer IRQ vector is on a different priority level,
* to work around the 'lost local interrupt if more than 2 IRQ
* sources per level' errata.
*/
#define LOCAL_TIMER_VECTOR 0xef
#define LOCAL_TIMER_VECTOR 0xef
/*
* Performance monitoring interrupt vector:
*/
#define LOCAL_PERF_VECTOR 0xee
#define LOCAL_PERF_VECTOR 0xee
/*
* First APIC vector available to drivers: (vectors 0x30-0xee) we
* start at 0x31(0x41) to spread out vectors evenly between priority
* levels. (0x80 is the syscall vector)
*/
#define FIRST_DEVICE_VECTOR (IRQ15_VECTOR + 2)
#define FIRST_DEVICE_VECTOR (IRQ15_VECTOR + 2)
#define NR_VECTORS 256
#define NR_VECTORS 256
#define FPU_IRQ 13
#define FPU_IRQ 13
#define FIRST_VM86_IRQ 3
#define LAST_VM86_IRQ 15
#define invalid_vm86_irq(irq) ((irq) < 3 || (irq) > 15)
#define FIRST_VM86_IRQ 3
#define LAST_VM86_IRQ 15
#define invalid_vm86_irq(irq) ((irq) < 3 || (irq) > 15)
#define NR_IRQS_LEGACY 16
#define NR_IRQS_LEGACY 16
#ifdef CONFIG_X86_IO_APIC
@ -112,9 +136,9 @@
#ifndef CONFIG_SPARSE_IRQ
# if NR_CPUS < MAX_IO_APICS
# define NR_IRQS (NR_VECTORS + (32 * NR_CPUS))
# define NR_IRQS (NR_VECTORS + (32 * NR_CPUS))
# else
# define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))
# define NR_IRQS (NR_VECTORS + (32 * MAX_IO_APICS))
# endif
#else
# define NR_IRQS \
@ -124,7 +148,7 @@
#endif
#else /* !CONFIG_X86_IO_APIC: */
# define NR_IRQS 16
# define NR_IRQS 16
#endif
#endif /* _ASM_X86_IRQ_VECTORS_H */