Re: KVM: powerpc: Fix BUILD_BUG_ON condition

From: Stephen Rothwell
Date: Mon Nov 02 2009 - 01:08:29 EST


Hi Hollis, Avi,

This commit was added to the kvm tree recently:

> Author: Hollis Blanchard <hollisb@xxxxxxxxxx>
> Date: Fri Oct 23 00:35:30 2009 +0000
>
> KVM: powerpc: Fix BUILD_BUG_ON condition
>
> The old BUILD_BUG_ON implementation didn't work with __builtin_constant_p().
> Fixing that revealed this test had been inverted for a long time without
> anybody noticing...
>
> Signed-off-by: Hollis Blanchard <hollisb@xxxxxxxxxx>
> Signed-off-by: Avi Kivity <avi@xxxxxxxxxx>
>
> diff --git a/arch/powerpc/kvm/timing.h b/arch/powerpc/kvm/timing.h
> index bb13b1f..a550f0f 100644
> --- a/arch/powerpc/kvm/timing.h
> +++ b/arch/powerpc/kvm/timing.h
> @@ -48,7 +48,7 @@ static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type) {}
> static inline void kvmppc_account_exit_stat(struct kvm_vcpu *vcpu, int type)
> {
> /* type has to be known at build time for optimization */
> - BUILD_BUG_ON(__builtin_constant_p(type));
> + BUILD_BUG_ON(!__builtin_constant_p(type));
> switch (type) {
> case EXT_INTR_EXITS:
> vcpu->stat.ext_intr_exits++;

It is OK as far as it goes. It still does not build, though, due to the
new BUILD_BUG_ON macro. So I have still commented out the BUILD_BUG_ON
in linux-next.

--
Cheers,
Stephen Rothwell sfr@xxxxxxxxxxxxxxxx
http://www.canb.auug.org.au/~sfr/

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