Merge tag 'x86-urgent-2024-08-11' of git://git.kernel.org/pub/scm/linux/kernel/git...

Merge tag 'x86-urgent-2024-08-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Thomas Gleixner:

 - Fix 32-bit PTI for real.

   pti_clone_entry_text() is called twice, once before initcalls so that
   initcalls can use the user-mode helper and then again after text is
   set read only. Setting read only on 32-bit might break up the PMD
   mapping, which makes the second invocation of pti_clone_entry_text()
   find the mappings out of sync and failing.

   Allow the second call to split the existing PMDs in the user mapping
   and synchronize with the kernel mapping.

 - Don't make acpi_mp_wake_mailbox read-only after init as the mail box
   must be writable in the case that CPU hotplug operations happen after
   boot. Otherwise the attempt to start a CPU crashes with a write to
   read only memory.

 - Add a missing sanity check in mtrr_save_state() to ensure that the
   fixed MTRR MSRs are supported.

   Otherwise mtrr_save_state() ends up in a #GP, which is fixed up, but
   the WARN_ON() can bring systems down when panic on warn is set.

* tag 'x86-urgent-2024-08-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mtrr: Check if fixed MTRRs exist before saving them
  x86/paravirt: Fix incorrect virt spinlock setting on bare metal
  x86/acpi: Remove __ro_after_init from acpi_mp_wake_mailbox
  x86/mm: Fix PTI for i386 some more