Re: [RFC v2 03/20] y2038: linux: Provide __clock_settime64 implementation

[Lukasz Majewski <lukma at denx dot de>]

Hi Florian,

> * Lukasz Majewski:
> 
> > Hi Arnd,
> >  
> >> We will probably keep them as an option in the kernel until 2038,
> >> but leave it to the distro or embedded system design to turn them
> >> on or off.  
> >
> > Isn't this the ABI break on demand ?  
> 
> Yes, it is.  It happened with vsyscall, too.
> 
> Stuff like that is only feasible if you expect that a dynamically
> linked libc is the ultimate ABI boundary for applications.  I don't
> think that's realistic or actually intended, especially for things
> like futexes.
> 
> > For following setup: WORDSIZE=32, TIMESIZE=32 and kernel with
> > __NR_clock_settime returning -ENOSYS (disabled by embedded system
> > designer in the kernel), but supporting __NR_clock_settime64 (for
> > example 32 bit ARM):
> >
> > The policy question - shall the user space binary after calling
> > clock_settime:
> >
> > 1. Receive -ENOSYS as the __NR_clock_settime was used to fulfill the
> > request
> >
> > or
> >
> > 2. Receive 0 (operation succeed) as the available
> > __NR_clock_settime64 has been used to perform the requested
> > operation.
> >
> >
> > For the proposed patch (clock_settime) - the option 2 is now
> > performed.  
> 
> In my opinion, an existing 32-bit architecture which does not provide
> the clock_settime system call (that it has provided before) is just
> broken, and will be so at least until 2038.

Am I correct, that you opt for first option that glibc shall return
just -ENOSYS in that case?


> 
> We can add the fallback code in glibc, but that will only give people
> the wrong idea that they can disable the 32-bit system calls.  It's
> just not true.
> 
> Thanks,
> Florian




Best regards,

Lukasz Majewski

--

DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de

Attachment: pgpeglklLiFMy.pgp
Description: OpenPGP digital signature