Messages in this thread | | | Date | Wed, 2 Oct 2019 09:03:33 +0200 | From | Michal Kubecek <> | Subject | Re: [PATCH 5.4-rc1 BUILD FIX] s390: mark __cpacf_query() as __always_inline |
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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.
Michal Kubecek
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