1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2008 CodeSourcery
3 Copyright (C) 2011-2013 Linaro Limited
4 Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
5
6 This file is part of libunwind.
7
8 Permission is hereby granted, free of charge, to any person obtaining
9 a copy of this software and associated documentation files (the
10 "Software"), to deal in the Software without restriction, including
11 without limitation the rights to use, copy, modify, merge, publish,
12 distribute, sublicense, and/or sell copies of the Software, and to
13 permit persons to whom the Software is furnished to do so, subject to
14 the following conditions:
15
16 The above copyright notice and this permission notice shall be
17 included in all copies or substantial portions of the Software.
18
19 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
23 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
24 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
25 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
26
27 #include "unwind_i.h"
28 #include "offsets.h"
29
30 /* Recognise PLT entries such as:
31 40ddf0: b0000570 adrp x16, 4ba000 <_GLOBAL_OFFSET_TABLE_+0x2a8>
32 40ddf4: f9433611 ldr x17, [x16,#1640]
33 40ddf8: 9119a210 add x16, x16, #0x668
34 40ddfc: d61f0220 br x17 */
35 static int
is_plt_entry(struct dwarf_cursor * c)36 is_plt_entry (struct dwarf_cursor *c)
37 {
38 unw_word_t w0, w1;
39 unw_accessors_t *a;
40 int ret;
41
42 a = unw_get_accessors_int (c->as);
43 if ((ret = (*a->access_mem) (c->as, c->ip, &w0, 0, c->as_arg)) < 0
44 || (ret = (*a->access_mem) (c->as, c->ip + 8, &w1, 0, c->as_arg)) < 0)
45 return 0;
46
47 ret = (((w0 & 0xff0000009f000000) == 0xf900000090000000)
48 && ((w1 & 0xffffffffff000000) == 0xd61f022091000000));
49
50 Debug (14, "ip=0x%lx => 0x%016lx 0x%016lx, ret = %d\n", c->ip, w0, w1, ret);
51 return ret;
52 }
53
54 static int
aarch64_handle_signal_frame(unw_cursor_t * cursor)55 aarch64_handle_signal_frame (unw_cursor_t *cursor)
56 {
57 struct cursor *c = (struct cursor *) cursor;
58 int ret;
59 unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
60 struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
61
62 if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
63 return -UNW_EUNSPEC;
64
65 ret = unw_is_signal_frame (cursor);
66 Debug(1, "unw_is_signal_frame()=%d\n", ret);
67
68 /* Save the SP and PC to be able to return execution at this point
69 later in time (unw_resume). */
70 c->sigcontext_sp = c->dwarf.cfa;
71 c->sigcontext_pc = c->dwarf.ip;
72
73 if (ret > 0)
74 {
75 c->sigcontext_format = AARCH64_SCF_LINUX_RT_SIGFRAME;
76 sc_addr = sp_addr + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
77 }
78 else
79 return -UNW_EUNSPEC;
80
81 c->sigcontext_addr = sc_addr;
82 c->frame_info.frame_type = UNW_AARCH64_FRAME_SIGRETURN;
83 c->frame_info.cfa_reg_offset = sc_addr - sp_addr;
84
85 /* Update the dwarf cursor.
86 Set the location of the registers to the corresponding addresses of the
87 uc_mcontext / sigcontext structure contents. */
88 c->dwarf.loc[UNW_AARCH64_X0] = DWARF_LOC (sc_addr + LINUX_SC_X0_OFF, 0);
89 c->dwarf.loc[UNW_AARCH64_X1] = DWARF_LOC (sc_addr + LINUX_SC_X1_OFF, 0);
90 c->dwarf.loc[UNW_AARCH64_X2] = DWARF_LOC (sc_addr + LINUX_SC_X2_OFF, 0);
91 c->dwarf.loc[UNW_AARCH64_X3] = DWARF_LOC (sc_addr + LINUX_SC_X3_OFF, 0);
92 c->dwarf.loc[UNW_AARCH64_X4] = DWARF_LOC (sc_addr + LINUX_SC_X4_OFF, 0);
93 c->dwarf.loc[UNW_AARCH64_X5] = DWARF_LOC (sc_addr + LINUX_SC_X5_OFF, 0);
94 c->dwarf.loc[UNW_AARCH64_X6] = DWARF_LOC (sc_addr + LINUX_SC_X6_OFF, 0);
95 c->dwarf.loc[UNW_AARCH64_X7] = DWARF_LOC (sc_addr + LINUX_SC_X7_OFF, 0);
96 c->dwarf.loc[UNW_AARCH64_X8] = DWARF_LOC (sc_addr + LINUX_SC_X8_OFF, 0);
97 c->dwarf.loc[UNW_AARCH64_X9] = DWARF_LOC (sc_addr + LINUX_SC_X9_OFF, 0);
98 c->dwarf.loc[UNW_AARCH64_X10] = DWARF_LOC (sc_addr + LINUX_SC_X10_OFF, 0);
99 c->dwarf.loc[UNW_AARCH64_X11] = DWARF_LOC (sc_addr + LINUX_SC_X11_OFF, 0);
100 c->dwarf.loc[UNW_AARCH64_X12] = DWARF_LOC (sc_addr + LINUX_SC_X12_OFF, 0);
101 c->dwarf.loc[UNW_AARCH64_X13] = DWARF_LOC (sc_addr + LINUX_SC_X13_OFF, 0);
102 c->dwarf.loc[UNW_AARCH64_X14] = DWARF_LOC (sc_addr + LINUX_SC_X14_OFF, 0);
103 c->dwarf.loc[UNW_AARCH64_X15] = DWARF_LOC (sc_addr + LINUX_SC_X15_OFF, 0);
104 c->dwarf.loc[UNW_AARCH64_X16] = DWARF_LOC (sc_addr + LINUX_SC_X16_OFF, 0);
105 c->dwarf.loc[UNW_AARCH64_X17] = DWARF_LOC (sc_addr + LINUX_SC_X17_OFF, 0);
106 c->dwarf.loc[UNW_AARCH64_X18] = DWARF_LOC (sc_addr + LINUX_SC_X18_OFF, 0);
107 c->dwarf.loc[UNW_AARCH64_X19] = DWARF_LOC (sc_addr + LINUX_SC_X19_OFF, 0);
108 c->dwarf.loc[UNW_AARCH64_X20] = DWARF_LOC (sc_addr + LINUX_SC_X20_OFF, 0);
109 c->dwarf.loc[UNW_AARCH64_X21] = DWARF_LOC (sc_addr + LINUX_SC_X21_OFF, 0);
110 c->dwarf.loc[UNW_AARCH64_X22] = DWARF_LOC (sc_addr + LINUX_SC_X22_OFF, 0);
111 c->dwarf.loc[UNW_AARCH64_X23] = DWARF_LOC (sc_addr + LINUX_SC_X23_OFF, 0);
112 c->dwarf.loc[UNW_AARCH64_X24] = DWARF_LOC (sc_addr + LINUX_SC_X24_OFF, 0);
113 c->dwarf.loc[UNW_AARCH64_X25] = DWARF_LOC (sc_addr + LINUX_SC_X25_OFF, 0);
114 c->dwarf.loc[UNW_AARCH64_X26] = DWARF_LOC (sc_addr + LINUX_SC_X26_OFF, 0);
115 c->dwarf.loc[UNW_AARCH64_X27] = DWARF_LOC (sc_addr + LINUX_SC_X27_OFF, 0);
116 c->dwarf.loc[UNW_AARCH64_X28] = DWARF_LOC (sc_addr + LINUX_SC_X28_OFF, 0);
117 c->dwarf.loc[UNW_AARCH64_X29] = DWARF_LOC (sc_addr + LINUX_SC_X29_OFF, 0);
118 c->dwarf.loc[UNW_AARCH64_X30] = DWARF_LOC (sc_addr + LINUX_SC_X30_OFF, 0);
119 c->dwarf.loc[UNW_AARCH64_SP] = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0);
120 c->dwarf.loc[UNW_AARCH64_PC] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
121 c->dwarf.loc[UNW_AARCH64_PSTATE] = DWARF_LOC (sc_addr + LINUX_SC_PSTATE_OFF, 0);
122
123 /* Set SP/CFA and PC/IP. */
124 dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_SP], &c->dwarf.cfa);
125 dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_PC], &c->dwarf.ip);
126
127 c->dwarf.pi_valid = 0;
128 c->dwarf.use_prev_instr = 0;
129
130 return 1;
131 }
132
133 int
unw_step(unw_cursor_t * cursor)134 unw_step (unw_cursor_t *cursor)
135 {
136 struct cursor *c = (struct cursor *) cursor;
137 int validate = c->validate;
138 int ret;
139
140 Debug (1, "(cursor=%p, ip=0x%016lx, cfa=0x%016lx))\n",
141 c, c->dwarf.ip, c->dwarf.cfa);
142
143 /* Validate all addresses before dereferencing. */
144 c->validate = 1;
145
146 /* Check if this is a signal frame. */
147 ret = unw_is_signal_frame (cursor);
148 if (ret > 0)
149 return aarch64_handle_signal_frame (cursor);
150 else if (unlikely (ret < 0))
151 {
152 /* IP points to non-mapped memory. */
153 /* This is probably SIGBUS. */
154 /* Try to load LR in IP to recover. */
155 Debug(1, "Invalid address found in the call stack: 0x%lx\n", c->dwarf.ip);
156 dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_X30], &c->dwarf.ip);
157 }
158
159 ret = dwarf_step (&c->dwarf);
160 Debug(1, "dwarf_step()=%d\n", ret);
161
162 /* Restore default memory validation state */
163 c->validate = validate;
164
165 if (unlikely (ret == -UNW_ESTOPUNWIND))
166 return ret;
167
168 if (unlikely (ret < 0))
169 {
170 /* DWARF failed. */
171
172 /*
173 * We could get here because of missing/bad unwind information.
174 * Validate all addresses before dereferencing.
175 */
176 if (c->dwarf.as == unw_local_addr_space)
177 {
178 c->validate = 1;
179 }
180
181 if (is_plt_entry (&c->dwarf))
182 {
183 Debug (2, "found plt entry\n");
184 c->frame_info.frame_type = UNW_AARCH64_FRAME_STANDARD;
185 }
186 else
187 {
188 Debug (2, "fallback\n");
189 c->frame_info.frame_type = UNW_AARCH64_FRAME_GUESSED;
190 }
191 /* Use link register (X30). */
192 c->frame_info.cfa_reg_offset = 0;
193 c->frame_info.cfa_reg_sp = 0;
194 c->frame_info.fp_cfa_offset = -1;
195 c->frame_info.lr_cfa_offset = -1;
196 c->frame_info.sp_cfa_offset = -1;
197 c->dwarf.loc[UNW_AARCH64_PC] = c->dwarf.loc[UNW_AARCH64_X30];
198 c->dwarf.loc[UNW_AARCH64_X30] = DWARF_NULL_LOC;
199 if (!DWARF_IS_NULL_LOC (c->dwarf.loc[UNW_AARCH64_PC]))
200 {
201 ret = dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_PC], &c->dwarf.ip);
202 if (ret < 0)
203 {
204 Debug (2, "failed to get pc from link register: %d\n", ret);
205 return ret;
206 }
207 Debug (2, "link register (x30) = 0x%016lx\n", c->dwarf.ip);
208 ret = 1;
209 }
210 else
211 c->dwarf.ip = 0;
212 }
213
214 return (c->dwarf.ip == 0) ? 0 : 1;
215 }
216