On Fri, Apr 21, 2023 at 3:58 PM Adhemerval Zanella Netto <adhemerval.zane...@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? To be clear, this is about memcpy calls made *during* very early startup, yes, but not *in* some special startup-only code (like init-first.c and hurdstartup.c for instance): that startup-specific code calls into the fairly generic code (mig_memcpy.c and the various MIG-generated RPC routines) that is used both during this very early startup and then much later during the normal runtime, and *that's* what calls memcpy. I'd like for memcpy calls in that generic code to both work during early startup and use the efficient memcpy implementation later. If dl-symbol-redir-ifunc.h can achieve that, please help me understand how. Sergey
