1 /* DWARF2 EH unwinding support for DragonFly BSD: AMD x86-64 and x86.
2 Copyright (C) 2014-2023 Free Software Foundation, Inc.
3 Contributed by John Marino <gnugcc@marino.st>
4
5 This file is part of GCC.
6
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)
10 any later version.
11
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.
16
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.
20
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/>. */
25
26 /* Do code reading to identify a signal frame, and set the frame
27 state data appropriately. See unwind-dw2.c for the structs. */
28
29 #include <sys/types.h>
30 #include <sys/sysctl.h>
31 #include <sys/param.h>
32 #include <signal.h>
33 #include <sys/ucontext.h>
34 #include <machine/sigframe.h>
35 #if __DragonFly_version > 400800
36 #include <sys/kinfo.h>
37 #endif
38
39
40 #define REG_NAME(reg) sf_uc.uc_mcontext.mc_## reg
41
42 #ifdef __x86_64__
43 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_dragonfly_fallback_frame_state
44
45
46 static int
47 x86_64_outside_sigtramp_range (unsigned char *pc)
48 {
49 static int sigtramp_range_determined = 0;
50 static unsigned char *sigtramp_start, *sigtramp_end;
51
52 if (sigtramp_range_determined == 0)
53 {
54 #if __DragonFly_version > 400800
55 struct kinfo_sigtramp kst = {0};
56 size_t len = sizeof (kst);
57 int mib[3] = { CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP };
58
59 sigtramp_range_determined = 1;
60 if (sysctl (mib, 3, &kst, &len, NULL, 0) == 0)
61 {
62 sigtramp_range_determined = 2;
63 sigtramp_start = kst.ksigtramp_start;
64 sigtramp_end = kst.ksigtramp_end;
65 }
66 #else
67 unsigned long ps_strings;
68 size_t len = sizeof (ps_strings);
69 int mib[2] = { CTL_KERN, KERN_PS_STRINGS };
70
71 sigtramp_range_determined = 1;
72 if (sysctl (mib, 2, &ps_strings, &len, NULL, 0) == 0)
73 {
74 sigtramp_range_determined = 2;
75 sigtramp_start = (unsigned char *)ps_strings - 32;
76 sigtramp_end = (unsigned char *)ps_strings;
77 }
78 #endif
79 }
80 if (sigtramp_range_determined < 2) /* sysctl failed if < 2 */
81 return 1;
82
83 return (pc < sigtramp_start || pc >= sigtramp_end );
84 }
85
86
87 static _Unwind_Reason_Code
88 x86_64_dragonfly_fallback_frame_state
89 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
90 {
91 struct sigframe *sf;
92 long new_cfa;
93
94 if (x86_64_outside_sigtramp_range(context->ra))
95 return _URC_END_OF_STACK;
96
97 sf = (struct sigframe *) context->cfa;
98 new_cfa = sf->REG_NAME(rsp);
99 fs->regs.cfa_how = CFA_REG_OFFSET;
100 /* Register 7 is rsp */
101 fs->regs.cfa_reg = 7;
102 fs->regs.cfa_offset = new_cfa - (long) context->cfa;
103
104 /* The SVR4 register numbering macros aren't usable in libgcc. */
105 fs->regs.how[0] = REG_SAVED_OFFSET;
106 fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(rax) - new_cfa;
107 fs->regs.how[1] = REG_SAVED_OFFSET;
108 fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(rdx) - new_cfa;
109 fs->regs.how[2] = REG_SAVED_OFFSET;
110 fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(rcx) - new_cfa;
111 fs->regs.how[3] = REG_SAVED_OFFSET;
112 fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(rbx) - new_cfa;
113 fs->regs.how[4] = REG_SAVED_OFFSET;
114 fs->regs.reg[4].loc.offset = (long)&sf->REG_NAME(rsi) - new_cfa;
115 fs->regs.how[5] = REG_SAVED_OFFSET;
116 fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(rdi) - new_cfa;
117 fs->regs.how[6] = REG_SAVED_OFFSET;
118 fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(rbp) - new_cfa;
119 fs->regs.how[8] = REG_SAVED_OFFSET;
120 fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(r8) - new_cfa;
121 fs->regs.how[9] = REG_SAVED_OFFSET;
122 fs->regs.reg[9].loc.offset = (long)&sf->REG_NAME(r9) - new_cfa;
123 fs->regs.how[10] = REG_SAVED_OFFSET;
124 fs->regs.reg[10].loc.offset = (long)&sf->REG_NAME(r10) - new_cfa;
125 fs->regs.how[11] = REG_SAVED_OFFSET;
126 fs->regs.reg[11].loc.offset = (long)&sf->REG_NAME(r11) - new_cfa;
127 fs->regs.how[12] = REG_SAVED_OFFSET;
128 fs->regs.reg[12].loc.offset = (long)&sf->REG_NAME(r12) - new_cfa;
129 fs->regs.how[13] = REG_SAVED_OFFSET;
130 fs->regs.reg[13].loc.offset = (long)&sf->REG_NAME(r13) - new_cfa;
131 fs->regs.how[14] = REG_SAVED_OFFSET;
132 fs->regs.reg[14].loc.offset = (long)&sf->REG_NAME(r14) - new_cfa;
133 fs->regs.how[15] = REG_SAVED_OFFSET;
134 fs->regs.reg[15].loc.offset = (long)&sf->REG_NAME(r15) - new_cfa;
135 fs->regs.how[16] = REG_SAVED_OFFSET;
136 fs->regs.reg[16].loc.offset = (long)&sf->REG_NAME(rip) - new_cfa;
137 fs->retaddr_column = 16;
138 fs->signal_frame = 1;
139 return _URC_NO_REASON;
140 }
141
142 #else /* Next section is for i386 */
143
144 #define MD_FALLBACK_FRAME_STATE_FOR x86_dragonfly_fallback_frame_state
145
146
147 static void
148 x86_sigtramp_range (unsigned char **start, unsigned char **end)
149 {
150 unsigned long ps_strings;
151 int mib[2];
152 size_t len;
153
154 mib[0] = CTL_KERN;
155 mib[1] = KERN_PS_STRINGS;
156 len = sizeof (ps_strings);
157 sysctl (mib, 2, &ps_strings, &len, NULL, 0);
158
159 *start = (unsigned char *)ps_strings - 128;
160 *end = (unsigned char *)ps_strings;
161 }
162
163
164 static _Unwind_Reason_Code
165 x86_dragonfly_fallback_frame_state
166 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
167 {
168 unsigned char *pc = context->ra;
169 unsigned char *sigtramp_start, *sigtramp_end;
170 struct sigframe *sf;
171 long new_cfa;
172
173 x86_sigtramp_range(&sigtramp_start, &sigtramp_end);
174
175 if (pc >= sigtramp_end || pc < sigtramp_start)
176 return _URC_END_OF_STACK;
177
178 sf = (struct sigframe *) context->cfa;
179 new_cfa = sf->REG_NAME(esp);
180 fs->regs.cfa_how = CFA_REG_OFFSET;
181 fs->regs.cfa_reg = 4;
182 fs->regs.cfa_offset = new_cfa - (long) context->cfa;
183
184 /* The SVR4 register numbering macros aren't usable in libgcc. */
185 fs->regs.how[0] = REG_SAVED_OFFSET;
186 fs->regs.reg[0].loc.offset = (long)&sf->REG_NAME(eax) - new_cfa;
187 fs->regs.how[3] = REG_SAVED_OFFSET;
188 fs->regs.reg[3].loc.offset = (long)&sf->REG_NAME(ebx) - new_cfa;
189 fs->regs.how[1] = REG_SAVED_OFFSET;
190 fs->regs.reg[1].loc.offset = (long)&sf->REG_NAME(ecx) - new_cfa;
191 fs->regs.how[2] = REG_SAVED_OFFSET;
192 fs->regs.reg[2].loc.offset = (long)&sf->REG_NAME(edx) - new_cfa;
193 fs->regs.how[6] = REG_SAVED_OFFSET;
194 fs->regs.reg[6].loc.offset = (long)&sf->REG_NAME(esi) - new_cfa;
195 fs->regs.how[7] = REG_SAVED_OFFSET;
196 fs->regs.reg[7].loc.offset = (long)&sf->REG_NAME(edi) - new_cfa;
197 fs->regs.how[5] = REG_SAVED_OFFSET;
198 fs->regs.reg[5].loc.offset = (long)&sf->REG_NAME(ebp) - new_cfa;
199 fs->regs.how[8] = REG_SAVED_OFFSET;
200 fs->regs.reg[8].loc.offset = (long)&sf->REG_NAME(eip) - new_cfa;
201 fs->retaddr_column = 8;
202 fs->signal_frame = 1;
203 return _URC_NO_REASON;
204 }
205 #endif /* ifdef __x86_64__ */