[ltt-dev] to find all the tracepoints by the __start___tracepoints and __stop___tracepoints

[ltt-dev] to find all the tracepoints by the __start___tracepoints and __stop___tracepoints

[long xu]

Hello,

I find when we use the fuction "tracepoint_update_probe_range", it usese the
"__start___tracepoints" and "__stop___tracepoints" to find all of the
tracepoints. But i don't find where it do the initialisation of the
"__start___tracepoints" and "__stop___tracepoints". How can they point the
first tracepoint and the last point?

Thanks,

Best Regard,

Long XU
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[ltt-dev] to find all the tracepoints by the __start___tracepoints and __stop___tracepoints

[long xu]

Hello,

I find when we use the fuction "tracepoint_update_probe_range", it usese the
"__start___tracepoints" and "__stop___tracepoints" to find all of the
tracepoints. But i don't find where it do the initialisation of the
"__start___tracepoints" and "__stop___tracepoints". How can they point the
first tracepoint and the last point?

Thanks,

Best Regard,

Long XU
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[ltt-dev] to find all the tracepoints by the __start___tracepoints and __stop___tracepoints

[long xu]

Hello,

I find when we use the fuction "tracepoint_update_probe_range", it usese the
"__start___tracepoints" and "__stop___tracepoints" to find all of the
tracepoints. But i don't find where it do the initialisation of the
"__start___tracepoints" and "__stop___tracepoints". How can they point the
first tracepoint and the last point?

Thanks,

Best Regard,

Long XU
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[ltt-dev] to find all the tracepoints by the __start___tracepoints and __stop___tracepoints

[Pierre-Marc Fournier]

Hello,

These symbols are automatically placed by the linker at the boundaries
of the __tracepoints section.

This magic is done in the linker script.

pmf

long xu wrote:
> Hello,
> 
> I find when we use the fuction "tracepoint_update_probe_range", it usese
> the "__start___tracepoints" and "__stop___tracepoints" to find all of
> the tracepoints. But i don't find where it do the initialisation of the
> "__start___tracepoints" and "__stop___tracepoints". How can they point
> the first tracepoint and the last point?
> 
> Thanks,
> 
> Best Regard,
> 
> Long XU
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev

[ltt-dev] to find all the tracepoints by the __start___tracepoints and __stop___tracepoints

[Mathieu Desnoyers]

And given we don't rely on such automagic linker features for the
kernel, include/asm-generic/vmlinux.lds.h specifies :

#define DATA_DATA
...
        VMLINUX_SYMBOL(__start___tracepoints) = .;                      \
        *(__tracepoints)                                                \
        VMLINUX_SYMBOL(__stop___tracepoints) = .;                       \

Therefore, as Pierre-Marc says, the linker is responsible for
initialising those symbols.

Mathieu


* Pierre-Marc Fournier (pierre-marc.fournier at polymtl.ca) wrote:
> Hello,
> 
> These symbols are automatically placed by the linker at the boundaries
> of the __tracepoints section.
> 
> This magic is done in the linker script.
> 
> pmf
> 
> long xu wrote:
> > Hello,
> > 
> > I find when we use the fuction "tracepoint_update_probe_range", it usese
> > the "__start___tracepoints" and "__stop___tracepoints" to find all of
> > the tracepoints. But i don't find where it do the initialisation of the
> > "__start___tracepoints" and "__stop___tracepoints". How can they point
> > the first tracepoint and the last point?
> > 
> > Thanks,
> > 
> > Best Regard,
> > 
> > Long XU
> > 
> > 
> > ------------------------------------------------------------------------
> > 
> > _______________________________________________
> > ltt-dev mailing list
> > ltt-dev at lists.casi.polymtl.ca
> > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 
> 
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 

-- 
Mathieu Desnoyers
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