x86, irq: add IRQ layout comments (9fc2e79d) · Commits · 戴 / test

arch/x86/include/asm/irq_vectors.h

+58 −34

Original line number	Diff line number	Diff line
		@@ -3,6 +3,29 @@

		#include <linux/threads.h>

		/*
		* 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

		/*
		@@ -27,6 +50,7 @@
		* 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)