On Wed, Oct 02, 2019 at 09:03:33AM +0200, Michal Kubecek wrote: > On Wed, Oct 02, 2019 at 08:46:05AM +0200, Heiko Carstens wrote: > > On Tue, Oct 01, 2019 at 10:08:01PM +0200, Jiri Kosina wrote: > > > > > > In file included from arch/s390/kvm/kvm-s390.c:44: > > > ./arch/s390/include/asm/cpacf.h: In function '__cpacf_query': > > > ./arch/s390/include/asm/cpacf.h:179:2: warning: asm operand 3 probably doesn't match constraints > > > 179 | asm volatile( > > > | ^~~ > > > ./arch/s390/include/asm/cpacf.h:179:2: error: impossible constraint in 'asm' > > > > > > ... > > > > > > I am wondering how is it possible that none of the build-testing > > > infrastructure we have running against linux-next caught this? Not enough > > > non-x86 coverage? > > > > Well, there is plenty of s390 coverage with respect to daily builds > > (also here). It doesn't fail for me with gcc 9.1; so you may either > > have a different gcc version or different config options(?) so the > > compiler decided to not inline the function. > > I think I found the reason: we only hit the build failure with one > special config used for zfcpdump which has > > CONFIG_CC_OPTIMIZE_FOR_SIZE=y > > When I switched to CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE=y (which we have > in other s390x configs and which most people probably prefer), the build > does not fail even without the patch. Yes, with CONFIG_CC_OPTIMIZE_FOR_SIZE=y I can see plenty of _additional_ compile failures on s390 with "defconfig". Will fix them all... Thanks for reporting!
