Re: [PATCH v11 15/40] arm64/sme: Implement SVCR context switching

On Mon, Feb 07, 2022 at 03:20:44PM +0000, Mark Brown wrote:

In SME the use of both streaming SVE mode and ZA are tracked through PSTATE.SM and PSTATE.ZA, visible through the system register SVCR. In order to context switch the floating point state for SME we need to context switch the contents of this register as part of context switching the floating point state.

Since changing the vector length exits streaming SVE mode and disables ZA we also make sure we update SVCR appropriately when setting vector length, and similarly ensure that new threads have streaming SVE mode and ZA disabled.

Signed-off-by: Mark Brown broonie@kernel.org

Reviewed-by: Catalin Marinas catalin.marinas@arm.com