1/* setjmp for x86-64.
2   Copyright (C) 2001-2022 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/* Don't save shadow stack register if shadow stack isn't enabled.  */
26#if !SHSTK_ENABLED
27# undef SHADOW_STACK_POINTER_OFFSET
28#endif
29
30ENTRY (__sigsetjmp)
31	/* Save registers.  */
32	movq %rbx, (JB_RBX*8)(%rdi)
33#ifdef PTR_MANGLE
34# ifdef __ILP32__
35	/* Save the high bits of %rbp first, since PTR_MANGLE will
36	   only handle the low bits but we cannot presume %rbp is
37	   being used as a pointer and truncate it.  Here we write all
38	   of %rbp, but the low bits will be overwritten below.  */
39	movq %rbp, (JB_RBP*8)(%rdi)
40# endif
41	mov %RBP_LP, %RAX_LP
42	PTR_MANGLE (%RAX_LP)
43	mov %RAX_LP, (JB_RBP*8)(%rdi)
44#else
45	movq %rbp, (JB_RBP*8)(%rdi)
46#endif
47	movq %r12, (JB_R12*8)(%rdi)
48	movq %r13, (JB_R13*8)(%rdi)
49	movq %r14, (JB_R14*8)(%rdi)
50	movq %r15, (JB_R15*8)(%rdi)
51	lea 8(%rsp), %RDX_LP	/* Save SP as it will be after we return.  */
52#ifdef PTR_MANGLE
53	PTR_MANGLE (%RDX_LP)
54#endif
55	movq %rdx, (JB_RSP*8)(%rdi)
56	mov (%rsp), %RAX_LP	/* Save PC we are returning to now.  */
57	LIBC_PROBE (setjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RAX_LP)
58#ifdef PTR_MANGLE
59	PTR_MANGLE (%RAX_LP)
60#endif
61	movq %rax, (JB_PC*8)(%rdi)
62
63#ifdef SHADOW_STACK_POINTER_OFFSET
64# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
65	/* Check if Shadow Stack is enabled.  */
66	testl $X86_FEATURE_1_SHSTK, %fs:FEATURE_1_OFFSET
67	jz L(skip_ssp)
68# else
69	xorl %eax, %eax
70# endif
71	/* Get the current Shadow-Stack-Pointer and save it.  */
72	rdsspq %rax
73	movq %rax, SHADOW_STACK_POINTER_OFFSET(%rdi)
74# if IS_IN (libc) && defined SHARED && defined FEATURE_1_OFFSET
75L(skip_ssp):
76# endif
77#endif
78#if IS_IN (rtld)
79	/* In ld.so we never save the signal mask.  */
80	xorl %eax, %eax
81	retq
82#else
83	/* Make a tail call to __sigjmp_save; it takes the same args.  */
84	jmp __sigjmp_save
85#endif
86END (__sigsetjmp)
87hidden_def (__sigsetjmp)
88