Re: Request for swapcontext and getcontext to be ported to our libc

["Simon 'corecode' Schubert" <corecode@xxxxxxxxxxxx>]

Matt Emmerton wrote:
> Simon wrote:
> > Matt Emmerton wrote:
> > > I've toyed with it a bit, but there are some issues I'm not sure how to
> > > solve (such as accessing curthread -- a kernel construct -- from
> userland).
> > > I would welcome discussion with the person who suggested it (corecode?).
> > In which way do you have to access curthread?  That's a kernel-only
> > entity, I don't think you have to access that in userland.  Besides, if we
> > take in the system call version, there is no need for a pure libc based
> > version anymore.
>
> Point taken, and that's definitely the path we're going down at the moment.
>
> However, I recall it being mentioned that the proliferation of syscalls is
> unneccessary, so a libc implementation would keep the kernel lean.

Once we have introduced this syscall, we can't remove it anymore for binary compatibility.

>  The
> reason we need curthread is to get access to the frame construct, which is
> neccessary to save the context.

when you are in userland, you have to build the frame yourself.

cheers
 simon

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