[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











More information about the Lazarus mailing list