[nneonneo]

From perusing the source of the MIT/GNU Scheme compiler, I suspect that “only” two changes are needed to support W^X:

- Compiled code needs to be allocated separately from Scheme objects. It can still be garbage collected and such - they will probably need to make a separate set of allocation functions for code vs. data. The closure/function objects can be made to point to the code, or, if they don’t need to be written often, simply allocated wholly from the “code” pages. - Before modifying any of the code (e.g. to patch addresses after GC relocation), a system-specific hook function will need to be called to set the permissions to RW. They already call an I-cache flush function after each modification, so this shouldn’t be too bad.

Some of the necessary changes are already sketched out in cmpint.txt. And, sooner or later, they’re going to have to make these changes: OpenBSD already enforces W^X (but provides a workaround), and MIT/GNU Scheme already applies a paxctl workaround to gain W|X on NetBSD.