Re: [PATCH] Linux Kernel Markers 0.5 for Linux 2.6.17 (with probe management)

["Frank Ch. Eigler" <fche at redhat dot com>]

Hi -

On Thu, Sep 21, 2006 at 08:50:29PM +0200, Ingo Molnar wrote:

> [...]  let me qualify that: parameters must be prepared there too -
> but no actual function call inserted. (at most a NOP
> inserted). [...]  Does a simple asm() that takes read-only
> parameters but only adds a NOP achieve this result?

You mean something like this?

#define MARK(n,v1,v2,v3) asm ("__mark_" #n ": nop" ::  \
                              "X" (v1), "X" (v2), "X" (v3))

I haven't been able to get gcc to emit any better debuginfo for
parameters pseudo-passed like this. 

(I've tested such a marker inserted into an inner loop of dhrystone.
It was compiled with "-ggdb -O3".  Neither gdb nor systemtap could
resolve the same values/symbols being passed as MARK() arguments,
though at least the breakpoint address was nicely marked.)

- FChE

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