x86-urgent-2021-09-26

 - Prevent sending the wrong signal when protection keys are enabled and
   the kernel handles a fault in the vsyscall emulation.

 - Invoke early_reserve_memory() before invoking e820_memory_setup() which
   is required to make the Xen dom0 e820 hooks work correctly.

 - Use the correct data type for the SETZ operand in the EMQCMDS
   instruction wrapper.

 - Prevent undefined behaviour to the potential unaligned accesss in the
   instroction decoder library.