[PATCH] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY

[Will Deacon]

On Mon, 17 Nov 2025 00:12:08 -0500, Jonathan Marek wrote:
> The "drop print" commit removed the whole branch and not just the print.
> For some ARM64 cpus, this leads to hard lockup when
> CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY is not enabled.
> 
> 

Applied (with your SoB) to arm64 (for-next/fixes), thanks!

[1/1] arm64: proton-pack: Fix hard lockup when !MITIGATE_SPECTRE_BRANCH_HISTORY
      https://git.kernel.org/arm64/c/165eb13e485c

I'd be inclined to remove CONFIG_MITIGATE_SPECTRE_BRANCH_HISTORY
entirely (i.e. make it unconditional) given the number of CPUs
affected and the dynamic controls we already have for the mitigation.

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev