2.2 ARM处理器工作模式

ARM Architecture Reference Manual

Arm 指令框架手册

1. 处理器7种工作模式

Processor mode	Mode number	Description
User usr	0b10000	Normal program execution mode
FIQ fiq	0b10001	Supports a high-speed data transfer or channel process
Supervisor svc	0b10011	A protected mode for the operating system
Abort abt	0b10111	Implements virtual memory and/or memory protection
Undefined und	0b11011	Supports software emulation of hardware coprocessors
System sys	0b11111	Runs privileged operating system tasks (ARMv4 and above)

Linux 应用程序运行在usr模式

Linux 内核运行在svc模式