On Fri, 2020-10-09 at 12:38 +0900, Hajime Tazaki wrote: > > > > +++ b/arch/um/nommu/Makefile.um > > > > [...] > > > > > +ifeq ($(shell uname -s), Linux) > > > +NPROC=$(shell nproc) > > > +else # e.g., FreeBSD > > > +NPROC=$(shell sysctl -n hw.ncpu) > > > +endif > > > > That seems very inappropriate here. > > Will cut the FreeBSD part. But even the NPROC and -j flag mangling seems ... awful? > > > --- /dev/null > > > +++ b/arch/um/nommu/include/asm/atomic64.h > > > > That doesn't make sense to me, you can control CONFIG_GENERIC_ATOMIC64 > > to be on, and don't need the ifdef and this file? > > We were suggested to not use GENERIC_ATOMIC64 on 64bit build during > our v3 patchset. So we actually control CONFIG_GENERIC_ATOMIC64 to be > on only when !64BIT, and thus need atomic64.h for the 64BIT build. > > https://lwn.net/ml/linux-arch/20200205093454.GG14879@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Well, yeah, but your architecture _is_ a piece of crap in needing atomic64 emulation? :-) How about just using the real atomic64 implementation like UML normally does? I mean, falling back to the actual underlying CPU. Or even gcc intrinsics? You've basically re-implemented CONFIG_GENERIC_ATOMIC64, so perhaps you've hidden it from PeterZ's view now because you're no longer touching the real generic atomic64 (which is for 32-bit machines), but that doesn't actually make this any *better*. Arguably *worse* since you've just copied it ... > > > +++ b/arch/um/nommu/um/delay.c > > > > why the double um/ path? > > This is because now in arch/um/Makefile, > > - SUBARCH := um/nommu > - HEADER_ARCH := $(SUBARCH) > - HOST_DIR := arch/$(HEADER_ARCH) > - core-y += $(HOST_DIR)/um > > the last line expands as arch/um/nommu/um. But is there a reason for it? Couldn't it be changed? Anyway, we're still debating the whole build system and layout so not much point in going into the details now ... johannes
