1/* setjmp for x86-64.
2 Copyright (C) 2001-2020 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