A couple of x86 fixes which missed rc1 due to my stupidity:
- Drop lazy TLB mode before switching to the temporary address space for
text patching. text_poke() switches to the temporary mm which clears
the lazy mode and restores the original mm afterwards. Due to clearing
lazy mode this might restore a already dead mm if exit_mmap() runs in
parallel on another CPU.
- Document the x32 syscall design fail vs. syscall numbers 512-547
properly.
- Fix the ORC unwinder to handle the inactive task frame correctly. This
was unearthed due to the slightly different code generation of GCC10.
- Use an up to date screen_info for the boot params of kexec instead of
the possibly stale and invalid version which happened to be valid when
the kexec kernel was loaded.