Re: [PATCH v2] arm64: Enable data independent timing (DIT) in the kernel

Will Deacon
2022-11-08T17:40:12Z

On Mon, 7 Nov 2022 18:24:00 +0100, Ard Biesheuvel wrote:
> The ARM architecture revision v8.4 introduces a data independent timing
> control (DIT) which can be set at any exception level, and instructs the
> CPU to avoid optimizations that may result in a correlation between the
> execution time of certain instructions and the value of the data they
> operate on.
>
> The DIT bit is part of PSTATE, and is therefore context switched as
> usual, given that it becomes part of the saved program state (SPSR) when
> taking an exception. We have also defined a hwcap for DIT, and so user
> space can discover already whether or nor DIT is available. This means
> that, as far as user space is concerned, DIT is wired up and fully
> functional.
>
> [...]

Applied to arm64 (for-next/cpufeature), thanks!

[1/1] arm64: Enable data independent timing (DIT) in the kernel
https://git.kernel.org/arm64/c/01ab991fc0ee

Cheers,
--
Will