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>

*** 22,31 ****
--- 22,35 ----
  /*
   * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
   * Use is subject to license terms.
   */
  
+ /*
+  * Copyright 2019 Joyent, Inc.
+  */
+ 
  #include <sys/asm_linkage.h>
  #ifndef __xpv
  #include <sys/xpv_support.h>
  #endif
  #include <sys/hypervisor.h>
*** 162,172 ****
          .size   hypercall_page, HYPERCALL_PAGESIZE
  #if defined(__amd64)
  #define TRAP_INSTR                      \
          shll    $5, %eax;               \
          addq    $hypercall_page, %rax;  \
!         jmp     *%rax
  #else
  #define TRAP_INSTR                      \
          shll    $5, %eax;               \
          addl    $hypercall_page, %eax;  \
          call    *%eax
--- 166,176 ----
          .size   hypercall_page, HYPERCALL_PAGESIZE
  #if defined(__amd64)
  #define TRAP_INSTR                      \
          shll    $5, %eax;               \
          addq    $hypercall_page, %rax;  \
!         INDIRECT_JMP_REG(rax);
  #else
  #define TRAP_INSTR                      \
          shll    $5, %eax;               \
          addl    $hypercall_page, %eax;  \
          call    *%eax