2016-02-24 20:45 GMT+01:00 Matt Fleming <[email protected]>: > On Wed, 24 Feb, at 10:56:13AM, Linus Torvalds wrote: >> On Wed, Feb 24, 2016 at 8:36 AM, Andy Lutomirski <[email protected]> wrote: >> >> >> >> So the EFI runtime crap should not change once it is mapped. And those >> >> should be global. It is only natural. >> > >> > Why is it natural? >> > >> > Long-term, I'd rather see EFI runtime services use an actual mm_struct >> > and use_mm. >> >> Definitely. >> >> The EFI runtime page mapping may be unchanging, but that doesn't mean >> we should be mapping it all the time - the mapping may not change, but >> we will change away from it. > > There is movement towards hanging the EFI memory map off of mm_struct > for x86. ARM and arm64 already do this and there were some patches > from Sylvain (Cc'd) to do this for the purposes of having a task > context that could be preempted while in the middle of an EFI runtime > call for some Intel platforms, > > > https://lkml.kernel.org/r/[email protected]
I was thinking we could use the efi kthread to handle the efi services generically, not only for the interruptible case, and have a way to decide if we allow interruptions inside the efi call itself or not. Then all runtime services would use an mm_struct. The drawback is that you will need two context switchs to be able to execute the runtime service. -- Sylvain
