11787 Kernel needs to be built with retpolines
11788 Kernel needs to generally use RSB stuffing
Reviewed by: Jerry Jelinek <jerry.jelinek@joyent.com>
Reviewed by: John Levon <john.levon@joyent.com>

*** 40,61 ****
   *    has been executed after this to make sure any pending speculations are
   *    captured. In general, this should be handled by the fact that callers of
   *    this are either going to change privilege levels or halt, which makes
   *    these operations safer.
   */
-         ENTRY_NP(x86_md_clear_noop)
-         ret
-         SET_SIZE(x86_md_clear_noop)
  
          /*
!          * This uses the microcode based means of flushing state. VERW will
!          * clobber flags.
           */
!         ENTRY_NP(x86_md_clear_verw)
          pushfq
          subq    $8, %rsp
          mov     %ds, (%rsp)
          verw    (%rsp)
          addq    $8, %rsp
          popfq
          ret
!         SET_SIZE(x86_md_clear_verw)
--- 40,63 ----
   *    has been executed after this to make sure any pending speculations are
   *    captured. In general, this should be handled by the fact that callers of
   *    this are either going to change privilege levels or halt, which makes
   *    these operations safer.
   */
  
          /*
!          * By default, x86_md_clear is disabled until the system determines that
!          * it both needs MDS related mitigations and we have microcode that
!          * provides the needed functionality.
!          *
!          * The VERW instruction clobbers flags which is why it's important that
!          * we save and restore them here.
           */
!         ENTRY_NP(x86_md_clear)
!         ret
          pushfq
          subq    $8, %rsp
          mov     %ds, (%rsp)
          verw    (%rsp)
          addq    $8, %rsp
          popfq
          ret
!         SET_SIZE(x86_md_clear)