arm64: entry: Allow tramp_alias to access symbols after the 4K boundary

commit 6c5bf79b69f911560fbf82214c0971af6e58e682 upstream.

Systems using kpti enter and exit the kernel through a trampoline mapping
that is always mapped even when the kernel is not. tramp_valias is a macro
to find the address of a symbol in the trampoline mapping.

Adding the extra sets of vectors will expand the size of the entry.tramp.text
section to beyond 4K. tramp_valias will be unable to generate addresses
for symbols beyond 4K as it uses the 12 bit immediate of the add
instruction.

As there are now two registers available when tramp_alias is called,
use the extra register to avoid the 4K limit of the 12 bit immediate.

Change-Id: I225b66c724b2d167d92d190715f885b465beb388
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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: ebcdd80d
Git-repo: https://android.googlesource.com/kernel/common/


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