On Tue, Feb 22, 2022 at 12:53:11PM +0000, Catalin Marinas wrote:

> I think I get this but a state diagram somewhere would help ;).

> IIUC you don't disable SM on a context switch, you just leave it in
> place until a task_fpsimd_load(). It shouldn't be a problem as
> kernel_neon_begin() disables it anyway.

Yes, streaming mode is part of the floating point state and this is how
we handle floating point in general - it's part of what's tracked with
TIF_FOREIGN_FPSTATE.  Unless we want to do something with floating point
we don't touch it.