This is the mail archive of the
libc-ports@sources.redhat.com
mailing list for the libc-ports project.
Re: [PATCH, RFC] MIPS: Implement the getcontext API
On Wed, Mar 04, 2009 at 09:19:28AM +0100, Brian Foster wrote:
> On Tuesday 03 March 2009 17:56:25 David Daney wrote:
> >[ ... ]
> > When (and if) we move the sigreturn trampoline to a vdso we should be
> > able to maintain the ABI.
>
> it's more a matter of âwhenâ rather than âifâ.
> there is still an intention here to use XI (we
> have SmartMIPS), which requires not using the
> signal (or FP) trampoline on the stack.
>
> moving the signal trampoline to a vdso (which
> is(? was?) called, maybe misleadingly, âvsyscallâ,
> on other architectures) is the obvious solution to
> that part of the puzzle. and yes, it is possible
> to maintain the ABI; the signal trampoline is still
> also put on the stack, and modulo XI, would work if
> used â the trampoline-on-stack is simply not used
> if there is a vdso with the signal trampoline.
We generally want to get rid of stack trampolines. Trampolines require
cacheflushing which especially on SMP systems can be a rather expensive
operation.
Ralf