On Thu, 5 Sep 2019, Josh Poimboeuf wrote: > On Thu, Sep 05, 2019 at 02:03:34PM +0200, Miroslav Benes wrote: > > > > + I would like to better understand the scope of the current > > > > problems. It is about modifying code in the livepatch that > > > > depends on position of the related code: > > > > > > > > + relocations are rather clear; we will need them anyway > > > > to access non-public (static) API from the original code. > > > > > > > > + What are the other changes? > > > > > > I think the .klp.arch sections are the big ones: > > > > > > .klp.arch.altinstructions > > > .klp.arch.parainstructions > > > .klp.arch.jump_labels (doesn't exist yet) > > > > > > And that's just x86... > > > > I may misunderstand, but we have .klp.arch sections because para and > > alternatives have to be processed after relocations. And if we cannot get > > rid of relocations completely, because of static symbols, then we cannot > > get rid of .klp.arch sections either. > > With late module patching gone, the module code can just process the klp > relocations at the same time it processes normal relocations. > > Then the normal module alt/para/jump_label processing code can be used > instead of arch_klp_init_object_loaded(). Ah, of course. I obviously cannot grasp the idea of not having late module patching :) > Note this also means that Joe's patches can remove copy_module_elf() and > free_module_elf(). And module_arch_freeing_init() in s390. Correct. So yes, it would simplify the code a lot. I am still worried about the consequences. > > > And then of course there's the klp coming/going notifiers which have > > > also been an additional source of complexity. > > > > True, but I think we (me and Petr) do not consider it as much of a problem > > as you. > > It's less of an issue than .klp.arch and all the related code which can > be removed. Ok. Miroslav
