Re: Getting ready to land native-compilation on master

[Eli Zaretskii]

> From: Alex Bennée <alex.bennee@linaro.org>
> Cc: wilde@sha-bang.de, akrl@sdf.org, emacs-devel@gnu.org
> Date: Wed, 14 Apr 2021 18:28:49 +0100
> 
> >>     sysctl -w security.pax.mprotect.global=0
> >>     sysctl -w security.pax.mprotect.enabled=0
> >>   This is not a Emacs specific problem but a problem with libgccjit
> >>   itself.  (The basic gcc jit "Hello World" example also fails with
> >>   memory protection in place).
> >
> > I'm not sure I understand why this happens, but I think this issue
> > should be reported to the GCC Bugzilla.
> 
> I suspect this is a change similar to the recent MacOS one where
> eXecutable pages cannot be mapped as Writable. The QEMU project recently
> had to implement split mappings for it's JIT to workaround this although
> I dare say there is probably a JIT interface that should be used to give
> suitable access to pages but that is something for the BSD experts to
> chime in on.

Are you sure this is relevant?  libgccjit, contrary to its name, is
not JIT code production, at least in Emacs.  It produces a file, a
shared library which is later loaded.  Why does this have to need
executable memory pages?