1/* BSD `setjmp' entry point to `sigsetjmp (..., 1)'.  i386 version.
2   Copyright (C) 1994-2021 Free Software Foundation, Inc.
3   This file is part of the GNU C Library.
4
5   The GNU C Library is free software; you can redistribute it and/or
6   modify it under the terms of the GNU Lesser General Public
7   License as published by the Free Software Foundation; either
8   version 2.1 of the License, or (at your option) any later version.
9
10   The GNU C Library is distributed in the hope that it will be useful,
11   but WITHOUT ANY WARRANTY; without even the implied warranty of
12   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13   Lesser General Public License for more details.
14
15   You should have received a copy of the GNU Lesser General Public
16   License along with the GNU C Library; if not, see
17   <https://www.gnu.org/licenses/>.  */
18
19/* This just does a tail-call to `__sigsetjmp (ARG, 1)'.
20   We cannot do it in C because it must be a tail-call, so frame-unwinding
21   in setjmp doesn't clobber the state restored by longjmp.  */
22
23#include <sysdep.h>
24#include <jmpbuf-offsets.h>
25#include <jmp_buf-ssp.h>
26#include <stap-probe.h>
27
28#define PARMS  4		/* no space for saved regs */
29#define JMPBUF PARMS
30#define SIGMSK JMPBUF+4
31
32/* Don't save shadow stack register if shadow stack isn't enabled.  */
33#if !SHSTK_ENABLED
34# undef SHADOW_STACK_POINTER_OFFSET
35#endif
36
37ENTRY (setjmp)
38	/* Note that we have to use a non-exported symbol in the next
39	   jump since otherwise gas will emit it as a jump through the
40	   PLT which is what we cannot use here.  */
41
42	movl JMPBUF(%esp), %eax
43
44	/* Save registers.  */
45	movl %ebx, (JB_BX*4)(%eax)
46	movl %esi, (JB_SI*4)(%eax)
47	movl %edi, (JB_DI*4)(%eax)
48	leal JMPBUF(%esp), %ecx	/* Save SP as it will be after we return.  */
49#ifdef PTR_MANGLE
50	PTR_MANGLE (%ecx)
51#endif
52	movl %ecx, (JB_SP*4)(%eax)
53	movl 0(%esp), %ecx	/* Save PC we are returning to now.  */
54	LIBC_PROBE (setjmp, 3, 4@%eax, -4@$1, 4@%ecx)
55#ifdef PTR_MANGLE
56	PTR_MANGLE (%ecx)
57#endif
58	movl %ecx, (JB_PC*4)(%eax)
59	movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer.  */
60#ifdef SHADOW_STACK_POINTER_OFFSET
61# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
62	/* Check if Shadow Stack is enabled.  */
63	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
64	jz L(skip_ssp)
65# else
66	xorl %ecx, %ecx
67# endif
68	/* Get the current Shadow-Stack-Pointer and save it.  */
69	rdsspd %ecx
70	movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
71# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
72L(skip_ssp):
73# endif
74#endif
75
76	/* Call __sigjmp_save.  */
77	pushl $1
78	cfi_adjust_cfa_offset (4)
79	pushl 8(%esp)
80	cfi_adjust_cfa_offset (4)
81	call __sigjmp_save
82	popl %ecx
83	cfi_adjust_cfa_offset (-4)
84	popl %edx
85	cfi_adjust_cfa_offset (-4)
86	ret
87END (setjmp)
88