Re: utrace comments

[Christoph Hellwig <hch@infradead.org>]

On Mon, Apr 30, 2007 at 10:33:31AM +0100, Russell King wrote:
> > Does the current arm ptrace code support single stepping in kernelspace?
> > If yes we absolutely need to continue to support it.
> 
> single stepping of user space code via standard ptrace calls, yes.
> 
> > > I'd also like to see utrace become *optional*
> > > for architectures to support, rather than as it currently stands as
> > > a *mandatory* requirement when merged.
> > 
> > No way we'd keep both the old ptrace mess and utrace in the same tree.
> 
> Given the stated arguments from yourself and Roland, that only leaves
> one solution to that.
> 
> I have no real problem with a decision being made to drop kernel-based
> single stepping _provided_ we have some replacement strategy in place
> and readily available.  At the moment I've not seen such a strategy.

Umm, no.  A major regression in the ptrace functionality for some
architectures is simply not acceptable.  We can't merge utrace if
we break existing userspace ABIs, and losing single stepping support
is exactly that.