Re: [RFC PATCH glibc 16/34] hurd: Add sys/ucontext.h and sigcontext.h for x86_64

[Samuel Thibault]

Sergey Bugaev, le lun. 10 avril 2023 22:13:06 +0300, a ecrit:
> On Mon, Apr 10, 2023 at 9:58 PM Samuel Thibault <samuel.thibault@gnu.org> 
> wrote:
> >
> > Sergey Bugaev, le dim. 19 mars 2023 18:09:59 +0300, a ecrit:
> > > +#ifdef __USE_GNU
> > > +/* Number of each register in the `gregset_t' array.  */
> > > +enum
> > > +{
> > > +  REG_GSFS = 0,              /* Actually int gs, fs.  */
> > > +# define REG_GSFS    REG_GSFS
> > > +  REG_ESDS,          /* Actually int es, ds.  */
> > > +# define REG_ESDS    REG_ESDS
> >
> > On second thought, why REG_ESDS? They are basically useless on amd64
> >
> > Linux packs all segment registers in REG_CSGSFS, probably better to
> > stuff them the same way? (all three really are 16bit only, even if the
> > thread_state is padding them to 32bits).
> 
> Exactly because that's how they are laid out in struct
> i386_thread_state, if you count in 8-byte chunks.

But we don't have to map to that.

Samuel