metag: SMP: Fix 4KiB stack setup on secondary CPUs
metag: SMP: Fix 4KiB stack setup on secondary CPUs

Back in early 2008, 4KiB stack support was added to reduce memory
consumption on workloads with lots of threads, using a separate IRQ
stack per CPU to alleviate stack pressure. However the SMP code added a
year and a half later didn't set up the IRQ stack when bringing up
secondary CPUs, resulting in a crash when SMP is configured with 4KiB
stacks, as soon as the first interrupt arrived on a secondary CPU.

Fix with calls to irq_ctx_exit()/irq_ctx_exit() when bringing up/down a
CPU.

Signed-off-by: James Hogan <547fa85bb3888a0222eed8ec39e36708605c6d53@imgtec.com>
Cc: 49b7025578db73bfe34c12503b8cd92ae51c4339@vger.kernel.org

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs