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

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