arm64: kernel: Fix unmasked debug exceptions when restoring mdscr_el1
Changes to make the resume from cpu_suspend() code behave more like
secondary boot caused debug exceptions to be unmasked early by
__cpu_setup(). We then go on to restore mdscr_el1 in cpu_do_resume(),
potentially taking break or watch points based on uninitialised registers.
Mask debug exceptions in cpu_do_resume(), which is specific to resume
from cpu_suspend(). Debug exceptions will be restored to their original
state by local_dbg_restore() in cpu_suspend(), which runs after
hw_breakpoint_restore() has re-initialised the other registers.
Reported-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Fixes: 23f20e4b7a3d ("arm64: Change cpu_resume() to enable mmu early then access sleep_sp by va") Cc: <stable@vger.kernel.org> # 4.7+ Signed-off-by: James Morse <james.morse@arm.com> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>