CloverBootloader/UefiCpuPkg/Include/StuffRsbNasm.inc

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;------------------------------------------------------------------------------
;
; 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