Re: [RFC][PATCH] x86: make text_poke() atomic

Arjan van de Ven
2009-03-02T18:55:14Z

On Mon, 2 Mar 2009 13:36:17 -0500
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:

> * Arjan van de Ven (arjan@infradead.org) wrote:
> > >
> > > Use map_vm_area() instead of vmap() in text_poke() for avoiding
> > > page allocation and delayed unmapping, and call
> > > vunmap_page_range() and local_flush_tlb() directly because this
> > > mapping is temporary and local.
> > >
> > > At the result of above change, text_poke() becomes atomic and can
> > > be called from stop_machine() etc.
> >
> > .... but text_poke() realistically needs to call stop_machine()
> > since you can't poke live code.... so that makes me wonder how
> > useful this is...
>
> Hi Arjan,
>
> Stop machine is not required when inserting a breakpoint.

that is your assumption; when I spoke with CPU architects they
cringed ;(

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