1/* Copyright (C) 2001-2018 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18#include <sysdep.h>
19#include <jmpbuf-offsets.h>
20#include <asm-syntax.h>
21#include <stap-probe.h>
22
23#include <sigaltstack-offsets.h>
24
25 .section .rodata.str1.1,"aMS",@progbits,1
26 .type longjmp_msg,@object
27longjmp_msg:
28 .string "longjmp causes uninitialized stack frame"
29 .size longjmp_msg, .-longjmp_msg
30
31
32//#define __longjmp ____longjmp_chk
33
34#ifdef PIC
35# define CALL_FAIL sub $8, %RSP_LP; \
36 cfi_remember_state; \
37 cfi_def_cfa_offset(16); \
38 lea longjmp_msg(%rip), %RDI_LP; \
39 call HIDDEN_JUMPTARGET(__fortify_fail); \
40 nop; \
41 cfi_restore_state
42#else
43# define CALL_FAIL sub $8, %RSP_LP; \
44 cfi_remember_state; \
45 cfi_def_cfa_offset(16); \
46 mov $longjmp_msg, %RDI_LP; \
47 call HIDDEN_JUMPTARGET(__fortify_fail); \
48 nop; \
49 cfi_restore_state
50#endif
51
52/* Jump to the position specified by ENV, causing the
53 setjmp call there to return VAL, or 1 if VAL is 0.
54 void __longjmp (__jmp_buf env, int val). */
55 .text
56ENTRY(____longjmp_chk)
57 /* Restore registers. */
58 mov (JB_RSP*8)(%rdi), %R8_LP
59 mov (JB_RBP*8)(%rdi),%R9_LP
60 mov (JB_PC*8)(%rdi), %RDX_LP
61#ifdef PTR_DEMANGLE
62 PTR_DEMANGLE (%R8_LP)
63 PTR_DEMANGLE (%R9_LP)
64 PTR_DEMANGLE (%RDX_LP)
65# ifdef __ILP32__
66 /* We ignored the high bits of the %rbp value because only the low
67 bits are mangled. But we cannot presume that %rbp is being used
68 as a pointer and truncate it, so recover the high bits. */
69 movl (JB_RBP*8 + 4)(%rdi), %eax
70 shlq $32, %rax
71 orq %rax, %r9
72# endif
73#endif
74
75 cmp %R8_LP, %RSP_LP
76 jbe .Lok
77
78 /* Save function parameters. */
79 movq %rdi, %r10
80 cfi_register (%rdi, %r10)
81 movl %esi, %ebx
82 cfi_register (%rsi, %rbx)
83
84 xorl %edi, %edi
85 lea -sizeSS(%rsp), %RSI_LP
86 movl $__NR_sigaltstack, %eax
87 syscall
88 /* Without working sigaltstack we cannot perform the test. */
89 testl %eax, %eax
90 jne .Lok2
91 testl $1, (-sizeSS + oSS_FLAGS)(%rsp)
92 jz .Lfail
93
94 mov (-sizeSS + oSS_SP)(%rsp), %RAX_LP
95 add (-sizeSS + oSS_SIZE)(%rsp), %RAX_LP
96 sub %R8_LP, %RAX_LP
97 cmp (-sizeSS + oSS_SIZE)(%rsp), %RAX_LP
98 jae .Lok2
99
100.Lfail: CALL_FAIL
101
102.Lok2: movq %r10, %rdi
103 cfi_restore (%rdi)
104 movl %ebx, %esi
105 cfi_restore (%rsi)
106
107.Lok:
108 LIBC_PROBE (longjmp, 3, LP_SIZE@%RDI_LP, -4@%esi, LP_SIZE@%RDX_LP)
109 /* We add unwind information for the target here. */
110 cfi_def_cfa(%rdi, 0)
111 cfi_register(%rsp,%r8)
112 cfi_register(%rbp,%r9)
113 cfi_register(%rip,%rdx)
114 cfi_offset(%rbx,JB_RBX*8)
115 cfi_offset(%r12,JB_R12*8)
116 cfi_offset(%r13,JB_R13*8)
117 cfi_offset(%r14,JB_R14*8)
118 cfi_offset(%r15,JB_R15*8)
119 movq (JB_RBX*8)(%rdi), %rbx
120 movq (JB_R12*8)(%rdi), %r12
121 movq (JB_R13*8)(%rdi), %r13
122 movq (JB_R14*8)(%rdi), %r14
123 movq (JB_R15*8)(%rdi), %r15
124 /* Set return value for setjmp. */
125 movl %esi, %eax
126 mov %R8_LP, %RSP_LP
127 movq %r9,%rbp
128 LIBC_PROBE (longjmp_target, 3,
129 LP_SIZE@%RDI_LP, -4@%eax, LP_SIZE@%RDX_LP)
130 jmpq *%rdx
131END (____longjmp_chk)
132