On Tue, Sep 01, 2020 at 05:05:53PM +0200, Christoph Hellwig wrote: > > Is there anything in particular that's tricky, or do you just want > > someone to look generally? From a quick grep arch/arm64/* looks clean, but > > I suspect that's misleading. > > Yes, it should be mostly trivial. I just bet the maintainers are > better at optimizing the low-level assembly code with the variable > address limit gone than I am. (See Linus comments on the x86 version > for example). And I don't have a physical arm64 to test with so I'd > have to rely on qemu for any testing.
So I looked at the arm64 code and I don't think it is entirely trivial, due to the orig_addr_limit saving in the syscall entry path, and due to all the UAO stuff. On the plus side it looks to me like CONFIG_ARM64_UAO and all the code relate to it can go away entirely if set_fs() is gone. So if I can trick you guys into submiting a patch on top of: http://git.infradead.org/users/hch/misc.git/shortlog/refs/heads/set_fs-removal that would make my life a lot simpler.
