[PATCH v1 21/38] arm64/sme: Implement SVCR context switching

[Jonathan Cameron]

On Thu, 30 Sep 2021 19:11:27 +0100
Mark Brown <broonie at kernel.org> 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 appropraitely when setting vector

appropriately

> length, and similarly ensure that new threads have streaming SVE mode
> and ZA disabled.
> 
> Signed-off-by: Mark Brown <broonie at kernel.org>
...