There are 7 modes in ARM.
User usr
Fast interrupt fiq
Interrupt irq
Supervisor svc
Abort abt
System sys
Undefined und
*************The following information in unreliable and still under construction***********
In Linux,
Userspace: usr mode
Kernel: svc mode
Interrupts and exceptions: irq, fiq, abt and und modes
TODO:
For what sys mode is used in Linux?
References:
http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0210c/Cihhcjia.html
