Re: CONFIG_THUMB2_KERNEL=y boot failure after Spectre BHB fixes
From: Christian Eggers
Date: Wed Mar 30 2022 - 14:29:51 EST
On Wednesday, 30 March 2022, 19:42:31 CEST, Ard Biesheuvel wrote:
> On Wed, 30 Mar 2022 at 19:33, Christian Eggers <ceggers@xxxxxxx> wrote:
> >
> > I just switched to v5.15.31-rt38 which already includes
> > 6c7cb60bff7a ("ARM: fix Thumb2 regression")
> >
> > This kernel boots fine now, even with CONFIG_HARDEN_BRANCH_HISTORY=y. After
> > applying the patch series from Ard, the system still boots fine.
> >
> > I haven't any understanding what these patches do. Is there anything I shall
> > test?
> >
>
> Thanks for confirming. The first fix affects all Thumb2
> configurations, my patch only affects Thumb2 configurations that
> actually enable the loop8 mitigation for Spectre-BHB.
>
> What type of CPU are you booting on?
>
NXP i.MX6ULL (ARM Cortex-A7).