[LEDE-DEV] [OpenWrt-Devel] [PATCH 0/5] x86: add support for microcode update

[Hauke Mehrtens]

On 02/09/2018 09:46 PM, Philip Prindeville wrote:
> 
> 
>> On Jan 18, 2018, at 2:15 PM, Hauke Mehrtens <hauke at hauke-m.de> wrote:
>>
>> On 01/18/2018 01:51 PM, Nick Lowe wrote:
>>> Does an update to the Kernel, 4.9.77 and 4.14.14 need to be made to
>>> properly address this? There are fixes to mitigate Spectre.
>>
>> We even need a patch for GCC which will be in GCC 8 and 7.3.
>> For master we should backport it to GCC 5.5, but what do we want to do
>> with 17.01 and 15.05 ?
>>
>> The AMD microcoded updater needs at least kernel 4.15, 4.14.13, 4.9.76,
>> 4.4.111  which we already have.
>>
>> Hauke
> 
> 
> For those of us following this from the sidelines (but not too closely), what’s the relationship of GCC to microcode updating?
> 
> -Philip

GCC 7.3 supports retpoline which helps to mitigate one of the Spectre
variants. Some of the mitigations are already done by some ASM code in
the kernel, but not everything.
The microcode update will provides some extra registers or instructions
to also mitigate Spectre or help the software to mitigate it.

Intel released here a plan which CPUs will get an updated microcode and
in which state it is:
https://newsroom.intel.com/wp-content/uploads/sites/11/2018/02/microcode-update-guidance.pdf

Hauke