At Mon, 30 Mar 2015 08:41:52 +0200,
Richard Weinberger wrote:

quoted

one more concern on the out-of-arch-tree design is that how
to handle our asm-generic-based header files
(arch/lib/include/asm). we have been heavily used
'generic-y' in the Kbuild file to reuse header files.

As noted before, libos is something in between. Maybe the asm-generic
stuff needs some modifications to make it work for libos.

okay.

BTW: There is something really fishy wrt to your build process.
I did a ARCH=i386 build due to my regular kernel work and later a ARCH=lib build.
It seems to pickup old/unrelated object files.
After a make clean ARCH=i386 it build fine.

---cut---
  LIB           liblinux-4.0.0-rc5.so
/usr/lib64/gcc/x86_64-suse-linux/4.8/../../../../x86_64-suse-linux/bin/ld: Warning: size of symbol `skb_copy_bits' changed from 10 in ./kernel/bpf/core.o to 441 in ./net/core/skbuff.o
./net/ipv6/fib6_rules.o: In function `fib6_rule_lookup':
/home/rw/linux/net/ipv6/fib6_rules.c:34: multiple definition of `fib6_rule_lookup'

(snip)

right now arch/lib/Makefile isn't fully on the Kbuild
system: build file dependency is not tracked at all.

while I should learn more about Kbuild, I'd be happy if you
would suggest how the Makefile should be.

---cut---

While we're talking about the build process, how can I cross build libos?
Say a i386 libos on x86_64. For UML we have use SUBARCH.
i.e. make linux ARCH=um SUBARCH=i386

the cross build is not either implemented. if libos needs it,
I'd start to think about the design: maybe SUBARCH-like
mechanism is required.

-- Hajime