arch: arm64: entry: fix trampoline for unhandled exceptions

(cherry pick from commit 9ee88e8b5e4e04a4619a1a9fa7d5078eb9430c6c)

These commits set up a trampoline in the AArch64 kernel entry points, to
optimize for Denver's branch predictor:

18cfa15 arm64: optimize el0_sync branch prediction
153bd39 arm64: optimize exception vector branch prediction

However these patches miss setting up the trampoline for the el0_inv
fallback case, which can happen e.g. when handling a PC alignment
exception caused by a compat task.  If the entry routines branch to
el0_inv without going through the trampoline, the kernel will handle the
exception but then panic when returning to userspace.

Bug: 24817444

Change-Id: I11045df3e35b8ddeb1133f73e3e41cef933e841c
Signed-off-by: Greg Hackmann <ghackmann@google.com>
1 file changed