I wonder, do ARM processors have special registers to support the idea of security rings and do operating systems such as Android, Palm or others support security rings?
In Wiki, there is some info that ARM processors don't have such registers as x86 for supporting such type of work.
But, I think that register is just the place with fixed size, where you can put and take info? So, the concept/idea of security rings is on OS only or x86-processors really have special registers for these aims, but on ARM-only OS is supporting this mode?
Am I right or not?
I have googled and wikied this topic, but there only few information, which isn't full.
There are no security rings. But there are different processor modes: http://www.heyrick.co.uk/assembler/regs.html , http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.dui0204j/Chdddhea.html
In short - most used are System and User. All userspace programs works in User mode. Kernel works in System mode.