arm64: fpsimd: Generalise context saving for non-task contexts

In preparation for allowing non-task (i.e., KVM vcpu) FPSIMD
contexts to be handled by the fpsimd common code, this patch adapts
task_fpsimd_save() to save back the currently loaded context,
removing the explicit dependency on current.

The relevant storage to write back to in memory is now found by
examining the fpsimd_last_state percpu struct.

fpsimd_save() does nothing unless TIF_FOREIGN_FPSTATE is clear, and
fpsimd_last_state is updated under local_bh_disable() or
local_irq_disable() everywhere that TIF_FOREIGN_FPSTATE is cleared:
thus, fpsimd_save() will write back to the correct storage for the
loaded context.

No functional change.

Signed-off-by: Dave Martin <[email protected]>
Reviewed-by: Alex Bennée <[email protected]>
Acked-by: Marc Zyngier <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>

0 files changed, 0 insertions, 0 deletions