arm64/mm: Treat faults taken by EFI runtime firmware as kernel faults

When EFI runtime services are invoked from a preemptible kthread, the
kthread runs with efi_mm installed via kthread_use_mm() and preemption
enabled, so neither faulthandler_disabled() nor !mm applies in
do_page_fault(). A permission fault taken by the firmware on one of its
own (TTBR0) mappings then hits the 'access to user memory outside
uaccess routines' check and oopses, without efi_runtime_fixup_exception()
ever being consulted.

efi_mm has no VMAs, so there is nothing for the mm to resolve. Send such
faults to no_context directly, so that __do_kernel_fault() can recover
from them as it does when the call is made with preemption disabled.

Fixes: a5baf582f4c0 ("arm64/efi: Call EFI runtime services without disabling preemption")
Cc: <stable@vger.kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

0 files changed, 0 insertions, 0 deletions