Hi, tl;dr: And IOMMU commit introduces a new user for sme_active() in generic code, and commit 284e21fab2cf x86, s390/mm: Move sme_active() and sme_me_mask to x86-specific header breaks the build of drivers/iommu/ for all architectures not implementing sme_active(). On Mon, Sep 02, 2019 at 04:39:51PM +1000, Stephen Rothwell wrote: > drivers/iommu/iommu.c: In function 'iommu_subsys_init': > drivers/iommu/iommu.c:123:38: error: implicit declaration of function 'sme_active'; did you mean 'cpu_active'? [-Werror=implicit-function-declaration] > 123 | if (iommu_default_passthrough() && sme_active()) { > | ^~~~~~~~~~ > | cpu_active > > Caused by commit > > 2cc13bb4f59f ("iommu: Disable passthrough mode when SME is active") Actually it is caused by: commit 284e21fab2cfcf90dacce565e0b12f29e5df00c1 Author: Thiago Jung Bauermann <bauerman@xxxxxxxxxxxxx> Date: Tue Aug 6 01:49:17 2019 -0300 x86, s390/mm: Move sme_active() and sme_me_mask to x86-specific header which removes the sme_active prototype from the generic headers. The iommu commit is in next already for a couple of days and didn't cause problems before. > sme_active() seems to be only relevant to X86. It has an implementation on x86 and s390. > I have reverted that commit for today. Thanks, but I suggest reverting above commit instead. Regards, Joerg