[Lazarus] EpikTimer v1.0.1 released
Lukasz Sokol
el.es.cr at gmail.com
Wed Jun 18 13:31:52 CEST 2014
On 18/06/14 11:27, Michael Schnell wrote:
> On 06/06/2014 12:25 PM, Michael Van Canneyt wrote:
>>
>>
>> if you do a vDSO implementation, please do not limit the
>> implementation to the clock_gettime, but implement all calls that
>> support it.
>>
>
> First testing results:
>
> On Kernel 3.1.10 (32 bit): - I do find the vDSO ELF structure
> (always at FFFFE000) - it seems to provide "__kernel_sigreturn",
> "__kernel_rt_sigreturn" , and "__kernel_vsyscall"
>
>
> On Kernel 3.2.0 64 bit, using a 32 Bit testing program: - I do find
> the vDSO ELF structure at (e.g. at F774300, the location varies for
> any program start. This behavior is documented for vDSO) - it also
> seems to provide "just __kernel_sigreturn", "__kernel_rt_sigreturn" ,
> and "__kernel_vsyscall"
>
> So I seem to be out of luck hoping for vDSO support for the
> performance counter or similar arch depending time-source access with
> 32 bit systems :-(
>
> It _might_ be possible the __kernel_vsyscall could be done in a way
> that it provides arch independent timer counter access that stays in
> user mode if possible. I'll keep researching...
>
> -Michael
>
I guess it's because
http://kernelnewbies.org/Linux_3.15-DriversArch#head-293bf8d606065cc1e6324f65a017e79144467d3f
i.e. explicit time functions support was just added recently to mainline...
Lukasz
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