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>

*** 306,316 ****
  
          movq    %rbp, %rdi
          call    av_dispatch_nmivect
  
          INTR_POP
!         call    *x86_md_clear
          jmp     tr_iret_auto
          /*NOTREACHED*/
          SET_SIZE(nmiint)
  
  #elif defined(__i386)
--- 306,316 ----
  
          movq    %rbp, %rdi
          call    av_dispatch_nmivect
  
          INTR_POP
!         call    x86_md_clear
          jmp     tr_iret_auto
          /*NOTREACHED*/
          SET_SIZE(nmiint)
  
  #elif defined(__i386)
*** 1024,1034 ****
          cmpl    $T_LASTFAST, %eax
          ja      1f
          orl     %eax, %eax      /* (zero extend top 32-bits) */
          leaq    fasttable(%rip), %r11
          leaq    (%r11, %rax, CLONGSIZE), %r11
!         jmp     *(%r11)
  1:
          /*
           * Fast syscall number was illegal.  Make it look
           * as if the INT failed.  Modify %rip to point before the
           * INT, push the expected error code and fake a GP fault.
--- 1024,1035 ----
          cmpl    $T_LASTFAST, %eax
          ja      1f
          orl     %eax, %eax      /* (zero extend top 32-bits) */
          leaq    fasttable(%rip), %r11
          leaq    (%r11, %rax, CLONGSIZE), %r11
!         movq    (%r11), %r11
!         INDIRECT_JMP_REG(r11)
  1:
          /*
           * Fast syscall number was illegal.  Make it look
           * as if the INT failed.  Modify %rip to point before the
           * INT, push the expected error code and fake a GP fault.
*** 1084,1094 ****
           * XXX a constant would be nicer.
           */
          ENTRY_NP(fast_null)
          XPV_TRAP_POP
          orq     $PS_C, 24(%rsp) /* set carry bit in user flags */
!         call    *x86_md_clear
          jmp     tr_iret_auto
          /*NOTREACHED*/
          SET_SIZE(fast_null)
  
  #elif defined(__i386)
--- 1085,1095 ----
           * XXX a constant would be nicer.
           */
          ENTRY_NP(fast_null)
          XPV_TRAP_POP
          orq     $PS_C, 24(%rsp) /* set carry bit in user flags */
!         call    x86_md_clear
          jmp     tr_iret_auto
          /*NOTREACHED*/
          SET_SIZE(fast_null)
  
  #elif defined(__i386)