On Wed, Jul 13, 2022 at 1:22 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Wed, Jul 13, 2022 at 01:35:22PM +0200, Peter Zijlstra wrote:
> > On Wed, Jul 13, 2022 at 12:28:38PM +0100, Sudip Mukherjee (Codethink) wrote:
> > > Hi All,
> > >
> > > The latest mainline kernel branch fails to build for x86_64 allmodconfig
> > > with clang and the error is:
> > >
<snip>
> > extern u64 spec_ctrl_current(void);
> >
>
> I hate headers...
very short commit message :D
>
> ---
> diff --git a/arch/x86/include/asm/nospec-branch.h b/arch/x86/include/asm/nospec-branch.h
> index bb05ed4f46bd..cbc3b8348939 100644
> --- a/arch/x86/include/asm/nospec-branch.h
> +++ b/arch/x86/include/asm/nospec-branch.h
> @@ -280,7 +280,6 @@ static inline void indirect_branch_prediction_barrier(void)
>
> /* The Intel SPEC CTRL MSR base value cache */
> extern u64 x86_spec_ctrl_base;
> -extern u64 x86_spec_ctrl_current;
> extern void write_spec_ctrl_current(u64 val, bool force);
> extern u64 spec_ctrl_current(void);
>
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index be7c19374fdd..b64512978534 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -6831,6 +6831,8 @@ void noinstr vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp)
> }
> }
>
> +DECLARE_PER_CPU(u64, x86_spec_ctrl_current);
> +
> void noinstr vmx_spec_ctrl_restore_host(struct vcpu_vmx *vmx,
> unsigned int flags)
> {
The build failure is fixed with this change. Thanks.
--
Regards
Sudip
