1 /* DWARF2 EH unwinding support for FreeBSD: AMD x86-64 and x86.
2 Copyright (C) 2015 Free Software Foundation, Inc.
3 Contributed by John Marino <gnugcc@marino.st>
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify
8 it under the terms of the GNU General Public License as published by
9 the Free Software Foundation; either version 3, or (at your option)
12 GCC is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 GNU General Public License for more details.
17 Under Section 7 of GPL version 3, you are granted additional
18 permissions described in the GCC Runtime Library Exception, version
19 3.1, as published by the Free Software Foundation.
21 You should have received a copy of the GNU General Public License and
22 a copy of the GCC Runtime Library Exception along with this program;
23 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 <http://www.gnu.org/licenses/>. */
26 /* Do code reading to identify a signal frame, and set the frame
27 state data appropriately. See unwind-dw2.c for the structs. */
29 #include <sys/types.h>
31 #include <sys/ucontext.h>
32 #include <machine/sigframe.h>
34 #define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg
37 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_freebsd_fallback_frame_state
39 static _Unwind_Reason_Code
40 x86_64_freebsd_fallback_frame_state
41 (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
46 /* Prior to FreeBSD 9, the signal trampoline was located immediately
47 before the ps_strings. To support non-executable stacks on AMD64,
48 the sigtramp was moved to a shared page for FreeBSD 9. Unfortunately
49 this means looking frame patterns again (sys/amd64/amd64/sigtramp.S)
50 rather than using the robust and convenient KERN_PS_STRINGS trick.
52 <pc + 00>: lea 0x10(%rsp),%rdi
54 <pc + 17>: mov $0x1a1,%rax
57 If we can't find this pattern, we're at the end of the stack.
60 if (!( *(unsigned int *)(context
->ra
) == 0x247c8d48
61 && *(unsigned int *)(context
->ra
+ 4) == 0x48006a10
62 && *(unsigned int *)(context
->ra
+ 8) == 0x01a1c0c7
63 && *(unsigned int *)(context
->ra
+ 12) == 0x050f0000 ))
64 return _URC_END_OF_STACK
;
66 sf
= (struct sigframe
*) context
->cfa
;
67 new_cfa
= sf
->REG_NAME(rsp
);
68 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
69 /* Register 7 is rsp */
71 fs
->regs
.cfa_offset
= new_cfa
- (long) context
->cfa
;
73 /* The SVR4 register numbering macros aren't usable in libgcc. */
74 fs
->regs
.reg
[0].how
= REG_SAVED_OFFSET
;
75 fs
->regs
.reg
[0].loc
.offset
= (long)&sf
->REG_NAME(rax
) - new_cfa
;
76 fs
->regs
.reg
[1].how
= REG_SAVED_OFFSET
;
77 fs
->regs
.reg
[1].loc
.offset
= (long)&sf
->REG_NAME(rdx
) - new_cfa
;
78 fs
->regs
.reg
[2].how
= REG_SAVED_OFFSET
;
79 fs
->regs
.reg
[2].loc
.offset
= (long)&sf
->REG_NAME(rcx
) - new_cfa
;
80 fs
->regs
.reg
[3].how
= REG_SAVED_OFFSET
;
81 fs
->regs
.reg
[3].loc
.offset
= (long)&sf
->REG_NAME(rbx
) - new_cfa
;
82 fs
->regs
.reg
[4].how
= REG_SAVED_OFFSET
;
83 fs
->regs
.reg
[4].loc
.offset
= (long)&sf
->REG_NAME(rsi
) - new_cfa
;
84 fs
->regs
.reg
[5].how
= REG_SAVED_OFFSET
;
85 fs
->regs
.reg
[5].loc
.offset
= (long)&sf
->REG_NAME(rdi
) - new_cfa
;
86 fs
->regs
.reg
[6].how
= REG_SAVED_OFFSET
;
87 fs
->regs
.reg
[6].loc
.offset
= (long)&sf
->REG_NAME(rbp
) - new_cfa
;
88 fs
->regs
.reg
[8].how
= REG_SAVED_OFFSET
;
89 fs
->regs
.reg
[8].loc
.offset
= (long)&sf
->REG_NAME(r8
) - new_cfa
;
90 fs
->regs
.reg
[9].how
= REG_SAVED_OFFSET
;
91 fs
->regs
.reg
[9].loc
.offset
= (long)&sf
->REG_NAME(r9
) - new_cfa
;
92 fs
->regs
.reg
[10].how
= REG_SAVED_OFFSET
;
93 fs
->regs
.reg
[10].loc
.offset
= (long)&sf
->REG_NAME(r10
) - new_cfa
;
94 fs
->regs
.reg
[11].how
= REG_SAVED_OFFSET
;
95 fs
->regs
.reg
[11].loc
.offset
= (long)&sf
->REG_NAME(r11
) - new_cfa
;
96 fs
->regs
.reg
[12].how
= REG_SAVED_OFFSET
;
97 fs
->regs
.reg
[12].loc
.offset
= (long)&sf
->REG_NAME(r12
) - new_cfa
;
98 fs
->regs
.reg
[13].how
= REG_SAVED_OFFSET
;
99 fs
->regs
.reg
[13].loc
.offset
= (long)&sf
->REG_NAME(r13
) - new_cfa
;
100 fs
->regs
.reg
[14].how
= REG_SAVED_OFFSET
;
101 fs
->regs
.reg
[14].loc
.offset
= (long)&sf
->REG_NAME(r14
) - new_cfa
;
102 fs
->regs
.reg
[15].how
= REG_SAVED_OFFSET
;
103 fs
->regs
.reg
[15].loc
.offset
= (long)&sf
->REG_NAME(r15
) - new_cfa
;
104 fs
->regs
.reg
[16].how
= REG_SAVED_OFFSET
;
105 fs
->regs
.reg
[16].loc
.offset
= (long)&sf
->REG_NAME(rip
) - new_cfa
;
106 fs
->retaddr_column
= 16;
107 fs
->signal_frame
= 1;
108 return _URC_NO_REASON
;
111 #else /* Next section is for i386 */
113 #define MD_FALLBACK_FRAME_STATE_FOR x86_freebsd_fallback_frame_state
116 * We can't use KERN_PS_STRINGS anymore if we want to support FreeBSD32
117 * compat on AMD64. The sigtramp is in a shared page in that case so the
118 * x86_sigtramp_range only works on a true i386 system. We have to
119 * search for the sigtramp frame if we want it working everywhere.
122 static _Unwind_Reason_Code
123 x86_freebsd_fallback_frame_state
124 (struct _Unwind_Context
*context
, _Unwind_FrameState
*fs
)
130 * i386 sigtramp frame we are looking for follows.
131 * Apparently PSL_VM is variable, so we can't look past context->ra + 4
133 * 0: ff 54 24 10 call *0x10(%esp) *SIGF_HANDLER
134 * 4: 8d 44 24 20 lea 0x20(%esp),%eax SIGF_UC
136 * 9: f7 40 54 00 00 02 00 testl $0x20000,0x54(%eax) $PSL_VM
137 * 10: 75 03 jne 15 <sigcode+0x15>
138 * 12: 8e 68 14 mov 0x14(%eax),%gs UC_GS
139 * 15: b8 a1 01 00 00 mov 0x1a1,%eax $SYS_sigreturn
142 if (!( *(unsigned int *)(context
->ra
- 4) == 0x102454ff
143 && *(unsigned int *)(context
->ra
) == 0x2024448d ))
144 return _URC_END_OF_STACK
;
146 sf
= (struct sigframe
*) context
->cfa
;
147 new_cfa
= sf
->REG_NAME(esp
);
148 fs
->regs
.cfa_how
= CFA_REG_OFFSET
;
149 fs
->regs
.cfa_reg
= 4;
150 fs
->regs
.cfa_offset
= new_cfa
- (long) context
->cfa
;
152 /* The SVR4 register numbering macros aren't usable in libgcc. */
153 fs
->regs
.reg
[0].how
= REG_SAVED_OFFSET
;
154 fs
->regs
.reg
[0].loc
.offset
= (long)&sf
->REG_NAME(eax
) - new_cfa
;
155 fs
->regs
.reg
[3].how
= REG_SAVED_OFFSET
;
156 fs
->regs
.reg
[3].loc
.offset
= (long)&sf
->REG_NAME(ebx
) - new_cfa
;
157 fs
->regs
.reg
[1].how
= REG_SAVED_OFFSET
;
158 fs
->regs
.reg
[1].loc
.offset
= (long)&sf
->REG_NAME(ecx
) - new_cfa
;
159 fs
->regs
.reg
[2].how
= REG_SAVED_OFFSET
;
160 fs
->regs
.reg
[2].loc
.offset
= (long)&sf
->REG_NAME(edx
) - new_cfa
;
161 fs
->regs
.reg
[6].how
= REG_SAVED_OFFSET
;
162 fs
->regs
.reg
[6].loc
.offset
= (long)&sf
->REG_NAME(esi
) - new_cfa
;
163 fs
->regs
.reg
[7].how
= REG_SAVED_OFFSET
;
164 fs
->regs
.reg
[7].loc
.offset
= (long)&sf
->REG_NAME(edi
) - new_cfa
;
165 fs
->regs
.reg
[5].how
= REG_SAVED_OFFSET
;
166 fs
->regs
.reg
[5].loc
.offset
= (long)&sf
->REG_NAME(ebp
) - new_cfa
;
167 fs
->regs
.reg
[8].how
= REG_SAVED_OFFSET
;
168 fs
->regs
.reg
[8].loc
.offset
= (long)&sf
->REG_NAME(eip
) - new_cfa
;
169 fs
->retaddr_column
= 8;
170 fs
->signal_frame
= 1;
171 return _URC_NO_REASON
;
173 #endif /* ifdef __x86_64__ */