[PATCH 07/14] ARM: spectre-v2: add Cortex A8 and A15 validation of the IBE bit

[Florian Fainelli]

On 05/16/2018 04:01 AM, Russell King wrote:
> When the branch predictor hardening is enabled, firmware must have set
> the IBE bit in the auxiliary control register.  If this bit has not
> been set, the Spectre workarounds will not be functional.
> 
> Add validation that this bit is set, and print a warning at alert level
> if this is not the case.
> 
> Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>

Reviewed-by: Florian Fainelli <f.fainelli at gmail.com>

I would be keen on updating arch/arm/kernel/head.S to to attempt setting
ACTRL[0]=1 on A15/B15, if the kernel executes at the appropriate
privilege level, this will succeed, if not, this should result in an
ignored write. What do you think?
-- 
Florian