arm64: entry: Add macro for reading symbol addresses from the trampoline

commit b28a8eebe81c186fdb1a0078263b30576c8e1f42 upstream.

The trampoline code needs to use the address of symbols in the wider
kernel, e.g., vectors. PC-relative addressing wouldn't work as the
trampoline code doesn't run at the address the linker expected.

tramp_ventry uses a literal pool, unless CONFIG_RANDOMIZE_BASE is
set in which case it uses the data page as a literal pool because
the data page can be unmapped when running in user-space, which is
required for CPUs vulnerable to meltdown.

Pull this logic out as a macro instead of adding a third copy
of it.

Change-Id: Ic2c62933b6a49c15f572c40e430a83bfa50dedae
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: e18876b5
Git-repo: https://android.googlesource.com/kernel/common/


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