Re: [linux-next:master 7083/12380] include/linux/compiler_types.h:517:45: error: call to '__compiletime_assert_845' declared with attribute error: BUILD_BUG_ON failed: !__builtin_constant_p(sr)

[Marc Zyngier <maz@kernel.org>]

On Wed, 20 Nov 2024 10:09:36 +0000,
kernel test robot <lkp@intel.com> wrote:
> 
> tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> head:   ac24e26aa08fe026804f678599f805eb13374a5d
> commit: a0162020095e2a34a59fc64c07183cc039e759f6 [7083/12380] KVM: arm64: Extend masking facility to arbitrary registers
> config: arm64-randconfig-004-20241120 (https://download.01.org/0day-ci/archive/20241120/202411201857.ZNudtGJl-lkp@intel.com/config)
> compiler: aarch64-linux-gcc (GCC) 14.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241120/202411201857.ZNudtGJl-lkp@intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202411201857.ZNudtGJl-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    In file included from <command-line>:
>    arch/arm64/kvm/nested.c: In function 'set_sysreg_masks':
> >> include/linux/compiler_types.h:517:45: error: call to '__compiletime_assert_845' declared with attribute error: BUILD_BUG_ON failed: !__builtin_constant_p(sr)

That's annoying. CONFIG_CC_OPTIMIZE_FOR_SIZE=y is what generates the
(legitimate) breakage. The hack below addresses it.

	M.

diff --git a/arch/arm64/kvm/nested.c b/arch/arm64/kvm/nested.c
index aeaa6017ffd89..9b36218b48def 100644
--- a/arch/arm64/kvm/nested.c
+++ b/arch/arm64/kvm/nested.c
@@ -951,7 +951,7 @@ u64 kvm_vcpu_apply_reg_masks(const struct kvm_vcpu *vcpu,
 	return v;
 }
 
-static void set_sysreg_masks(struct kvm *kvm, int sr, u64 res0, u64 res1)
+static __always_inline void set_sysreg_masks(struct kvm *kvm, int sr, u64 res0, u64 res1)
 {
 	int i = sr - __SANITISED_REG_START__;
 

-- 
Without deviation from the norm, progress is not possible.