1 /* DWARF2 EH unwinding support for AMD x86-64 and x86.
2 Copyright (C) 2009-2023 Free Software Foundation, Inc.
3
4 This file is part of GCC.
5
6 GCC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 3, or (at your option)
9 any later version.
10
11 GCC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
15
16 Under Section 7 of GPL version 3, you are granted additional
17 permissions described in the GCC Runtime Library Exception, version
18 3.1, as published by the Free Software Foundation.
19
20 You should have received a copy of the GNU General Public License and
21 a copy of the GCC Runtime Library Exception along with this program;
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 <http://www.gnu.org/licenses/>. */
24
25 /* Do code reading to identify a signal frame, and set the frame
26 state data appropriately. See unwind-dw2.c for the structs. */
27
28 #include <ucontext.h>
29 #include <sys/frame.h>
30
31 #ifdef __x86_64__
32
33 #define MD_FALLBACK_FRAME_STATE_FOR x86_64_fallback_frame_state
34
35 static _Unwind_Reason_Code
36 x86_64_fallback_frame_state (struct _Unwind_Context *context,
37 _Unwind_FrameState *fs)
38 {
39 unsigned char *pc = context->ra;
40 mcontext_t *mctx;
41 long new_cfa;
42
43 if (/* Solaris 10+
44 ------------
45 <__sighndlr+0>: push %rbp
46 <__sighndlr+1>: mov %rsp,%rbp
47 <__sighndlr+4>: callq *%rcx
48 <__sighndlr+6>: leaveq <--- PC
49 <__sighndlr+7>: retq */
50 *(unsigned long *)(pc - 6) == 0xc3c9d1ffe5894855)
51
52 /* We need to move up three frames:
53
54 <signal handler> <-- context->cfa
55 __sighndlr
56 call_user_handler
57 sigacthandler
58 <kernel>
59
60 context->cfa points into the frame after the saved frame pointer and
61 saved pc (struct frame).
62
63 The ucontext_t structure is in the kernel frame after the signal
64 number and a siginfo_t *. Since the frame sizes vary even within
65 Solaris 10 updates, we need to walk the stack to get there. */
66 {
67 struct frame *fp = (struct frame *) context->cfa - 1;
68 struct handler_args {
69 int signo;
70 siginfo_t *sip;
71 ucontext_t ucontext;
72 } *handler_args;
73 ucontext_t *ucp;
74
75 /* Next frame: __sighndlr frame pointer. */
76 fp = (struct frame *) fp->fr_savfp;
77 /* call_user_handler frame pointer. */
78 fp = (struct frame *) fp->fr_savfp;
79 /* sigacthandler frame pointer. */
80 fp = (struct frame *) fp->fr_savfp;
81
82 /* The argument area precedes the struct frame. */
83 handler_args = (struct handler_args *) (fp + 1);
84 ucp = &handler_args->ucontext;
85 mctx = &ucp->uc_mcontext;
86 }
87 else
88 return _URC_END_OF_STACK;
89
90 new_cfa = mctx->gregs[REG_RSP];
91
92 fs->regs.cfa_how = CFA_REG_OFFSET;
93 fs->regs.cfa_reg = 7;
94 fs->regs.cfa_offset = new_cfa - (long) context->cfa;
95
96 /* The SVR4 register numbering macros aren't usable in libgcc. */
97 fs->regs.how[0] = REG_SAVED_OFFSET;
98 fs->regs.reg[0].loc.offset = (long)&mctx->gregs[REG_RAX] - new_cfa;
99 fs->regs.how[1] = REG_SAVED_OFFSET;
100 fs->regs.reg[1].loc.offset = (long)&mctx->gregs[REG_RDX] - new_cfa;
101 fs->regs.how[2] = REG_SAVED_OFFSET;
102 fs->regs.reg[2].loc.offset = (long)&mctx->gregs[REG_RCX] - new_cfa;
103 fs->regs.how[3] = REG_SAVED_OFFSET;
104 fs->regs.reg[3].loc.offset = (long)&mctx->gregs[REG_RBX] - new_cfa;
105 fs->regs.how[4] = REG_SAVED_OFFSET;
106 fs->regs.reg[4].loc.offset = (long)&mctx->gregs[REG_RSI] - new_cfa;
107 fs->regs.how[5] = REG_SAVED_OFFSET;
108 fs->regs.reg[5].loc.offset = (long)&mctx->gregs[REG_RDI] - new_cfa;
109 fs->regs.how[6] = REG_SAVED_OFFSET;
110 fs->regs.reg[6].loc.offset = (long)&mctx->gregs[REG_RBP] - new_cfa;
111 fs->regs.how[8] = REG_SAVED_OFFSET;
112 fs->regs.reg[8].loc.offset = (long)&mctx->gregs[REG_R8] - new_cfa;
113 fs->regs.how[9] = REG_SAVED_OFFSET;
114 fs->regs.reg[9].loc.offset = (long)&mctx->gregs[REG_R9] - new_cfa;
115 fs->regs.how[10] = REG_SAVED_OFFSET;
116 fs->regs.reg[10].loc.offset = (long)&mctx->gregs[REG_R10] - new_cfa;
117 fs->regs.how[11] = REG_SAVED_OFFSET;
118 fs->regs.reg[11].loc.offset = (long)&mctx->gregs[REG_R11] - new_cfa;
119 fs->regs.how[12] = REG_SAVED_OFFSET;
120 fs->regs.reg[12].loc.offset = (long)&mctx->gregs[REG_R12] - new_cfa;
121 fs->regs.how[13] = REG_SAVED_OFFSET;
122 fs->regs.reg[13].loc.offset = (long)&mctx->gregs[REG_R13] - new_cfa;
123 fs->regs.how[14] = REG_SAVED_OFFSET;
124 fs->regs.reg[14].loc.offset = (long)&mctx->gregs[REG_R14] - new_cfa;
125 fs->regs.how[15] = REG_SAVED_OFFSET;
126 fs->regs.reg[15].loc.offset = (long)&mctx->gregs[REG_R15] - new_cfa;
127 fs->regs.how[16] = REG_SAVED_OFFSET;
128 fs->regs.reg[16].loc.offset = (long)&mctx->gregs[REG_RIP] - new_cfa;
129 fs->retaddr_column = 16;
130 fs->signal_frame = 1;
131
132 return _URC_NO_REASON;
133 }
134
135 #else
136
137 #define MD_FALLBACK_FRAME_STATE_FOR x86_fallback_frame_state
138
139 static _Unwind_Reason_Code
140 x86_fallback_frame_state (struct _Unwind_Context *context,
141 _Unwind_FrameState *fs)
142 {
143 unsigned char *pc = context->ra;
144 mcontext_t *mctx;
145 long new_cfa;
146
147 if (/* Solaris 11 since snv_125
148 -------------------------
149 <__sighndlr+0> push %ebp
150 <__sighndlr+1> mov %esp,%ebp
151 <__sighndlr+3> and $0xfffffff0,%esp
152 <__sighndlr+6> sub $0x4,%esp
153 <__sighndlr+9> pushl 0x10(%ebp)
154 <__sighndlr+12> pushl 0xc(%ebp)
155 <__sighndlr+15> pushl 0x8(%ebp)
156 <__sighndlr+18> call *0x14(%ebp)
157 <__sighndlr+21> leave <--- PC
158 <__sighndlr+22> ret */
159 (*(unsigned long *)(pc - 21) == 0x83ec8b55
160 && *(unsigned long *)(pc - 17) == 0xec83f0e4
161 && *(unsigned long *)(pc - 13) == 0x1075ff04
162 && *(unsigned long *)(pc - 9) == 0xff0c75ff
163 && *(unsigned long *)(pc - 5) == 0x55ff0875
164 && (*(unsigned long *)(pc - 1) & 0x00ffffff) == 0x00c3c914))
165 {
166 struct handler_args {
167 int signo;
168 siginfo_t *sip;
169 ucontext_t *ucontext;
170 } *handler_args = context->cfa;
171 mctx = &handler_args->ucontext->uc_mcontext;
172 }
173 else
174 return _URC_END_OF_STACK;
175
176 new_cfa = mctx->gregs[UESP];
177
178 fs->regs.cfa_how = CFA_REG_OFFSET;
179 fs->regs.cfa_reg = 4;
180 fs->regs.cfa_offset = new_cfa - (long) context->cfa;
181
182 /* The SVR4 register numbering macros aren't usable in libgcc. */
183 fs->regs.how[0] = REG_SAVED_OFFSET;
184 fs->regs.reg[0].loc.offset = (long)&mctx->gregs[EAX] - new_cfa;
185 fs->regs.how[3] = REG_SAVED_OFFSET;
186 fs->regs.reg[3].loc.offset = (long)&mctx->gregs[EBX] - new_cfa;
187 fs->regs.how[1] = REG_SAVED_OFFSET;
188 fs->regs.reg[1].loc.offset = (long)&mctx->gregs[ECX] - new_cfa;
189 fs->regs.how[2] = REG_SAVED_OFFSET;
190 fs->regs.reg[2].loc.offset = (long)&mctx->gregs[EDX] - new_cfa;
191 fs->regs.how[6] = REG_SAVED_OFFSET;
192 fs->regs.reg[6].loc.offset = (long)&mctx->gregs[ESI] - new_cfa;
193 fs->regs.how[7] = REG_SAVED_OFFSET;
194 fs->regs.reg[7].loc.offset = (long)&mctx->gregs[EDI] - new_cfa;
195 fs->regs.how[5] = REG_SAVED_OFFSET;
196 fs->regs.reg[5].loc.offset = (long)&mctx->gregs[EBP] - new_cfa;
197 fs->regs.how[8] = REG_SAVED_OFFSET;
198 fs->regs.reg[8].loc.offset = (long)&mctx->gregs[EIP] - new_cfa;
199 fs->retaddr_column = 8;
200
201 /* SIGFPE for IEEE-754 exceptions is delivered after the faulting insn
202 rather than before it, so don't set fs->signal_frame in that case.
203 We test whether the ES field of the Status Register is zero. */
204 if ((mctx->fpregs.fp_reg_set.fpchip_state.status & 0x80) == 0)
205 fs->signal_frame = 1;
206
207 return _URC_NO_REASON;
208 }
209
210 #endif