switching to system mode

L

louka

Hi,

I've being thinking about this for a while.

Can someone tell me why, in an isr, we switch to system mode? This is specifically from abort/irq/fiq modes on the arm cpu.

regards.
 
From my understanding (on IA32/AMD64 platforms), some of the instructions that the ISR requires are privileged instructions which can only be used from RING 0. As for the ARM, I have no idea, but I suspect it's the same reason.
 
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