Re: [VERY RFC PATCH 2/2] hurd: Make it possible to call memcpy very early

[Samuel Thibault]

Sergey Bugaev, le ven. 21 avril 2023 16:56:57 +0300, a ecrit:
> On Fri, Apr 21, 2023 at 3:58 PM Adhemerval Zanella Netto
> <adhemerval.zanella@linaro.org> wrote:
> > > Yes, sure, I wasn't really suggesting we do that change. My point is,
> > > I would like to make the same memcpy callsites both work during early
> > > startup and start calling the more efficient implementation once early
> > > startup is done -- if that's possible.
> >
> > That's the whole idea of dl-symbol-redir-ifunc.h, since it is explicit
> > enable by TU.
> 
> Then I must be misunderstanding how dl-symbol-redir-ifunc.h works
> (please explain!),
> 
> because I don't see how it would achieve that. Doesn't it change all
> memcpy calls in the current translation unit (.c file) to always call
> the baseline memcpy -- not only during startup, but even after the
> startup has been completed?

Perhaps we can generate "init" variants of the RPCs that we need at
initialization, that are made to use the base memcpy implementation, and
only use them in the init code?

Samuel