StuffRsbNasm.inc

;------------------------------------------------------------------------------
;
; Copyright (c) 2018, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
; Abstract:
;
;   This file provides macro definitions for stuffing the Return Stack Buffer (RSB)
;   for NASM files.
;
;------------------------------------------------------------------------------
 
%define RSB_STUFF_ENTRIES 0x20
 
;
; parameters:
; @param 1: register to use as counter (e.g. IA32:eax, X64:rax)
; @param 2: stack pointer to restore   (IA32:esp, X64:rsp)
; @param 3: the size of a stack frame  (IA32:4, X64:8)
;
%macro StuffRsb 3
      mov     %1, RSB_STUFF_ENTRIES / 2
  %%Unroll1:
      call    %%Unroll2
  %%SpecTrap1:
      pause
      lfence
      jmp     %%SpecTrap1
  %%Unroll2:
      call    %%StuffLoop
  %%SpecTrap2:
      pause
      lfence
      jmp     %%SpecTrap2
  %%StuffLoop:
      dec     %1
      jnz     %%Unroll1
      add     %2, RSB_STUFF_ENTRIES * %3 ; Restore the stack pointer
%endmacro
 
;
; RSB stuffing macros for IA32 and X64
;
%macro StuffRsb32 0
      StuffRsb     eax, esp, 4
%endmacro
 
%macro StuffRsb64 0
      StuffRsb     rax, rsp, 8
%endmacro