Re: [PATCH 1/2] arm64: entry: fix ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD

Rob Herring
2024-01-19T15:12:19Z

On Tue, Jan 16, 2024 at 5:02 AM Mark Rutland <mark.rutland@arm.com> wrote:
>
> Currently the ARM64_WORKAROUND_SPECULATIVE_UNPRIV_LOAD workaround isn't
> quite right, as it is supposed to be applied after the last explicit
> memory access, but is immediately followed by an LDR.

This isn't necessary. The LDR in question is an unprivileged load from
the EL0 stack. The erratum write-up is not really clear in that
regard.

It's the same as the KPTI case. After switching the page tables, there
are unprivileged loads from the EL0 stack.

Rob