Re: [PATCH] Linux Kernel Markers

Mathieu Desnoyers
2006-09-20T17:21:10Z

* Karim Yaghmour (karim@opersys.com) wrote:
>
> Masami Hiramatsu wrote:
> > This method is very similar to the djprobe.
> > And I had gotten the same idea to support preemptive kernel.
> ...
> > This means the below code, doesn't this?
> > ---
> > jmp 1f /* short jump consumes 2 bytes */
> > nop
> > nop
> > nop
> > 1:
>
> Actually this is slightly different (and requires more support
> on behalf of the underlying mechanism then what I was suggesting.)
> Basically, as was discussed elsewhere, there is some complex
> mechanisms required for taking care of the case where you got
> an interrupt at, say, the second or third nop. With the
> mechanism I'm suggesting (replacing a 5 byte jmp with a 5 byte
> jmp), the underlying mechanics do not require having to take
> care of the above-mentioned case.
>

Karim, the jmp already there targets the end of the region : no possible
executioni of the three following nops. Clever :)

Mathieu

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