On Thu, Jun 01, 2023 at 06:13:44PM +0000, Edgecombe, Rick P wrote: > > text_poke() _does_ create a separate RW mapping. > > Sorry, I meant a separate RW allocation. Ah yes, that makes sense > > > > > The thing that sucks about text_poke() is that it always does a full > > TLB > > flush, and AFAICT that's not remotely needed. What it really wants to > > be > > doing is conceptually just > > > > kmap_local() > > mempcy() > > kunmap_loca() > > flush_icache(); > > > > ...except that kmap_local() won't actually create a new mapping on > > non-highmem architectures, so text_poke() open codes it. > > Text poke creates only a local CPU RW mapping. It's more secure because > other threads can't write to it. *nod*, same as kmap_local > It also only needs to flush the local core when it's done since it's > not using a shared MM. Ahh! Thanks for that; perhaps the comment in text_poke() about IPIs could be a bit clearer. What is it (if anything) you don't like about text_poke() then? It looks like it's doing broadly similar things to kmap_local(), so should be in the same ballpark from a performance POV?
