On 2014-05-02 13:34, Mj Embd wrote:
Adding Marc to comment
Marc Please clarify the doubt
On Fri, May 2, 2014 at 5:15 PM, Mj Embd <mj.e...@gmail.com> wrote:
Hi,
As per a lot of linux documentation some components work in process
context and some work in interrupt context.
If we try to map these contexts to ARM processor modes then is it
safely to assume that
Process Context : CPSR.mode = SVC
Interrupt Context : CPSR.mode = IRQ
If not how to define interrupt context properly. Confusing at times.
Well, none of this is completely true.
Process context exists both in USR (process in user mode) and SVC
(process in kernel mode, executing a syscall for example).
As for interrupts, the processor indeed starts executing the interrupt
in IRQ mode, but this is a useless complication as far as Linux is
concerned, and we quickly switch to SVC (see the definition of the
vector_stub macro in arch/arm/kernel/entry-armv.S).
Hope this helps.
M.
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