Messages in this thread | | | Date | Mon, 02 Mar 2009 14:13:35 -0500 | From | Masami Hiramatsu <> | Subject | Re: [RFC][PATCH] x86: make text_poke() atomic |
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Arjan van de Ven wrote: > 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 ;(
Is that true even if modifying just one-byte (like int3 insertion) and we don't care synchronous write(that means code modification effects on other processors after a while)?
Thank you,
-- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America) Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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