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Re: "processor" abstraction


on Monday 07 October 2013 18:50:53 Mouse wrote:

> As for the minimal abstraction?  Here's a strawman:
> - mmap to access the coprocessor's memory
> - ways (read/write? ioctl?) to do various things:
> - - halt
> - - single-step
> - - run
> - - grab processor state (registers &c)
> - - set processor state

-- trigger interrupt(s) or other messaging mechanisms
-- read/write private memory which may not (easily) be mmap()able?

> I think a harder question will be privilege decisions.  Who gets to
> frob which coprocessors?  When?  How is this enforced?

And to open another can of worms - decide which parts of host memory the 
coprocessor may access. On SoCs it may be things like video memory which 
could be anywhere and may not even be physically contiguous.

have fun

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