[PATCH v2 4/6] x86/efi: Hoist page table switching code into efi_call_virt()

This change is a prerequisite for pending patches that switch to a dedicated EFI page table, instead of using 'trampoline_pgd' which shares PGD entries with 'swapper_pg_dir'. The pending patches make it impossible to dereference the runtime service function pointer without first switching %cr3.

[PATCH v2 4/6] x86/efi: Hoist page table switching code into efi_call_virt()

This change is a prerequisite for pending patches that switch to a dedicated EFI page table, instead of using 'trampoline_pgd' which shares PGD entries with 'swapper_pg_dir'. The pending patches make it impossible to dereference the runtime service function pointer without first switching %cr3.