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|
; $Id: stack-probe-vcc.asm $
;; @file
; IPRT - Stack related Visual C++ support routines.
;
;
; Copyright (C) 2022-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
;*********************************************************************************************************************************
;* Header Files *
;*********************************************************************************************************************************
%if 0 ; YASM's builtin SEH64 support doesn't cope well with code alignment, so use our own.
%define RT_ASM_WITH_SEH64
%else
%define RT_ASM_WITH_SEH64_ALT
%endif
%include "iprt/asmdefs.mac"
%include "iprt/x86.mac"
;;
; Probe stack to trigger guard faults, and for x86 to allocate stack space.
;
; @param xAX Frame size.
; @uses AMD64: Probably nothing. EAX is certainly not supposed to change.
; x86: ESP = ESP - EAX; EFLAGS, nothing else
;
ALIGNCODE(64)
GLOBALNAME_RAW __alloca_probe, __alloca_probe, function
BEGINPROC_RAW __chkstk
push xBP
SEH64_PUSH_xBP
mov xBP, xSP
SEH64_SET_FRAME_xBP 0
push xAX
SEH64_PUSH_GREG xAX
push xBX
SEH64_PUSH_GREG xBX
SEH64_END_PROLOGUE
;
; Adjust eax so we're relative to [xBP - xCB*2].
;
sub xAX, xCB * 4
jle .touch_loop_done ; jump if rax < xCB*4, very unlikely
;
; Subtract what's left of the current page from eax and only engage
; the touch loop if (int)xAX > 0.
;
lea ebx, [ebp - xCB * 2]
and ebx, PAGE_SIZE - 1
sub xAX, xBX
jnl .touch_loop ; jump if pages to touch.
.touch_loop_done:
pop xBX
pop xAX
leave
%ifndef RT_ARCH_X86
ret
%else
;
; Do the stack space allocation and jump to the return location.
;
sub esp, eax
add esp, 4
jmp dword [esp + eax - 4]
%endif
;
; The touch loop.
;
.touch_loop:
sub xBX, PAGE_SIZE
%if 1
mov [xBP + xBX - xCB * 2], bl
%else
or byte [xBP + xBX - xCB * 2], 0 ; non-destructive variant...
%endif
sub xAX, PAGE_SIZE
jnl .touch_loop
jmp .touch_loop_done
ENDPROC_RAW __chkstk
%ifdef RT_ARCH_X86
;;
; 8 and 16 byte aligned alloca w/ probing.
;
; This routine adjusts the allocation size so __chkstk will return a
; correctly aligned allocation.
;
; @param xAX Unaligned allocation size.
;
%macro __alloc_probe_xxx 1
ALIGNCODE(16)
BEGINPROC_RAW __alloca_probe_ %+ %1
push ecx
;
; Calc the ESP address after the allocation and adjust EAX so that it
; will be aligned as desired.
;
lea ecx, [esp + 8]
sub ecx, eax
and ecx, %1 - 1
add eax, ecx
jc .bad_alloc_size
.continue:
pop ecx
jmp __alloca_probe
.bad_alloc_size:
%ifdef RT_STRICT
int3
%endif
or eax, 0xfffffff0
jmp .continue
ENDPROC_RAW __alloca_probe_ %+ %1
%endmacro
__alloc_probe_xxx 16
__alloc_probe_xxx 8
%endif ; RT_ARCH_X86
|
