Re: [PATCH v2 00/17] arm64 SSBD (aka Spectre-v4) mitigation

[Marc Zyngier]

Hi Catalin,

On 31/05/18 17:41, Catalin Marinas wrote:
> On Tue, May 29, 2018 at 01:11:04PM +0100, Marc Zyngier wrote:
>> Marc Zyngier (17):
>>   arm/arm64: smccc: Add SMCCC-specific return codes
>>   arm64: Call ARCH_WORKAROUND_2 on transitions between EL0 and EL1
>>   arm64: Add per-cpu infrastructure to call ARCH_WORKAROUND_2
>>   arm64: Add ARCH_WORKAROUND_2 probing
>>   arm64: Add 'ssbd' command-line option
>>   arm64: ssbd: Add global mitigation state accessor
>>   arm64: ssbd: Skip apply_ssbd if not using dynamic mitigation
>>   arm64: ssbd: Restore mitigation status on CPU resume
>>   arm64: ssbd: Introduce thread flag to control userspace mitigation
>>   arm64: ssbd: Add prctl interface for per-thread mitigation
>>   arm64: KVM: Add HYP per-cpu accessors
>>   arm64: KVM: Add ARCH_WORKAROUND_2 support for guests
>>   arm64: KVM: Handle guest's ARCH_WORKAROUND_2 requests
>>   arm64: KVM: Add ARCH_WORKAROUND_2 discovery through
>>     ARCH_FEATURES_FUNC_ID
> 
> I queued the 14 patches above for 4.18.

I just realized that your for-next/core branch is based on
4.17-rc4, which means arch/arm64/kernel/ssbd.c won't compile
(it relies on some of the symbols introduced with the x86
stuff in 4.17-rc7.

You can work around it by adding the following hack: