1/* setjmp for i386.
2   Copyright (C) 1995-2021 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#include <sysdep.h>
20#include <jmpbuf-offsets.h>
21#include <jmp_buf-ssp.h>
22#include <asm-syntax.h>
23#include <stap-probe.h>
24
25#define PARMS	4		/* no space for saved regs */
26#define JMPBUF	PARMS
27#define SIGMSK	JMPBUF+4
28
29/* Don't save shadow stack register if shadow stack isn't enabled.  */
30#if !SHSTK_ENABLED
31# undef SHADOW_STACK_POINTER_OFFSET
32#endif
33
34ENTRY (__sigsetjmp)
35
36	movl JMPBUF(%esp), %eax
37
38	/* Save registers.  */
39	movl %ebx, (JB_BX*4)(%eax)
40	movl %esi, (JB_SI*4)(%eax)
41	movl %edi, (JB_DI*4)(%eax)
42	leal JMPBUF(%esp), %ecx	/* Save SP as it will be after we return.  */
43#ifdef PTR_MANGLE
44	PTR_MANGLE (%ecx)
45#endif
46	movl %ecx, (JB_SP*4)(%eax)
47	movl 0(%esp), %ecx	/* Save PC we are returning to now.  */
48	LIBC_PROBE (setjmp, 3, 4@%eax, -4@SIGMSK(%esp), 4@%ecx)
49#ifdef PTR_MANGLE
50	PTR_MANGLE (%ecx)
51#endif
52	movl %ecx, (JB_PC*4)(%eax)
53	movl %ebp, (JB_BP*4)(%eax) /* Save caller's frame pointer.  */
54
55#ifdef SHADOW_STACK_POINTER_OFFSET
56# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
57	/* Check if Shadow Stack is enabled.  */
58	testl $X86_FEATURE_1_SHSTK, %gs:FEATURE_1_OFFSET
59	jz L(skip_ssp)
60# else
61	xorl %ecx, %ecx
62# endif
63	/* Get the current Shadow-Stack-Pointer and save it.  */
64	rdsspd %ecx
65	movl %ecx, SHADOW_STACK_POINTER_OFFSET(%eax)
66# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
67L(skip_ssp):
68# endif
69#endif
70#if IS_IN (rtld)
71	/* In ld.so we never save the signal mask.  */
72	xorl %eax, %eax
73	ret
74#else
75	/* Make a tail call to __sigjmp_save; it takes the same args.  */
76	jmp __sigjmp_save
77#endif
78END (__sigsetjmp)
79hidden_def (__sigsetjmp)
80