On Fri, May 31, 2019 at 04:29:10PM +0200, Andrey Konovalov wrote: > On Thu, May 30, 2019 at 7:15 PM Catalin Marinas <catalin.mari...@arm.com> > wrote: > > On Tue, May 28, 2019 at 04:14:45PM +0200, Andrey Konovalov wrote: > > > Thanks for a lot of valuable input! I've read through all the replies > > > and got somewhat lost. What are the changes I need to do to this > > > series? > > > > > > 1. Should I move untagging for memory syscalls back to the generic > > > code so other arches would make use of it as well, or should I keep > > > the arm64 specific memory syscalls wrappers and address the comments > > > on that patch? > > > > Keep them generic again but make sure we get agreement with Khalid on > > the actual ABI implications for sparc. > > OK, will do. I find it hard to understand what the ABI implications > are. I'll post the next version without untagging in brk, mmap, > munmap, mremap (for new_address), mmap_pgoff, remap_file_pages, shmat > and shmdt.
It's more about not relaxing the ABI to accept non-zero top-byte unless we have a use-case for it. For mmap() etc., I don't think that's needed but if you think otherwise, please raise it. > > > 2. Should I make untagging opt-in and controlled by a command line > > > argument? > > > > Opt-in, yes, but per task rather than kernel command line option. > > prctl() is a possibility of opting in. > > OK. Should I store a flag somewhere in task_struct? Should it be > inheritable on clone? A TIF flag would do but I'd say leave it out for now (default opted in) until we figure out the best way to do this (can be a patch on top of this series). Thanks. -- Catalin
