arm64: Add percpu vectors for EL1

commit bd09128d16fac3c34b80bd6a29088ac632e8ce09 upstream.

The Spectre-BHB workaround adds a firmware call to the vectors. This
is needed on some CPUs but not others. To avoid the unaffected CPU in
a big or little pair from making the firmware call create per cpu vectors.
The per-cpu vectors only apply when returning from EL0.

Systems using KPTI can use the canonical 'full-fat' vectors directly at
EL1, the trampoline exit code will switch to this_cpu_vector on exit to
EL0. Systems not using KPTI should always use this_cpu_vector.
this_cpu_vector will point at a vector in tramp_vecs or
__bp_harden_el1_vectors, depending on whether KPTI is in use.

Change-Id: I9983edd36ee880f3f951f4933b6fa4fca5a91a5b
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Git-commit: 5b5ca260
Git-repo: https://android.googlesource.com/kernel/common/


Signed-off-by: Kishor Krishna Bhat <quic_kishkris@quicinc.com>