Re: [PATCH v3 2/5] y2038: Introduce internal for glibc struct __timespec64

[Lukasz Majewski <lukma at denx dot de>]

Hi Andreas,

> On Mai 07 2019, Lukasz Majewski <lukma@denx.de> wrote:
> 
> > +struct __timespec64
> > +{
> > +  __time64_t tv_sec;         /* Seconds */
> > +# if BYTE_ORDER == BIG_ENDIAN
> > +  int tv_pad: 32;            /* Padding named for checking/setting
> > */
> > +  __int32_t tv_nsec;         /* Nanoseconds */
> > +# else
> > +  __int32_t tv_nsec;         /* Nanoseconds */
> > +  int tv_pad: 32;            /* Padding named for checking/setting
> > */ +# endif  
> 
> No need to use a bitfield, since the padding is not fractional.

That bitfield is for following reasons:

1. Have a backup plan in the case if we need to copy and clear the
padding anyway before passing this structure to the kernel in the future
(as recently we discovered that for example x32 has a kernel bug with
clearing it).

2. Kernel syscalls (e.g. clock_settime64) expects on those systems two
values - each 8 bytes. To avoid any nasty surprises the explicit
padding was added.

> 
> Andreas.
> 




Best regards,

Lukasz Majewski

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