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)
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 ret;
138
139 Debug (1, "(cursor=%p, ip=0x%016lx, cfa=0x%016lx))\n",
140 c, c->dwarf.ip, c->dwarf.cfa);
141
142 /* Check if this is a signal frame. */
143 if (unw_is_signal_frame (cursor) > 0)
144 return aarch64_handle_signal_frame (cursor);
145
146 ret = dwarf_step (&c->dwarf);
147 Debug(1, "dwarf_step()=%d\n", ret);
148
149 if (unlikely (ret == -UNW_ESTOPUNWIND))
150 return ret;
151
152 if (unlikely (ret < 0))
153 {
154 /* DWARF failed. */
155 if (is_plt_entry (&c->dwarf))
156 {
157 Debug (2, "found plt entry\n");
158 c->frame_info.frame_type = UNW_AARCH64_FRAME_STANDARD;
159 }
160 else
161 {
162 Debug (2, "fallback\n");
163 c->frame_info.frame_type = UNW_AARCH64_FRAME_GUESSED;
164 }
165 /* Use link register (X30). */
166 c->frame_info.cfa_reg_offset = 0;
167 c->frame_info.cfa_reg_sp = 0;
168 c->frame_info.fp_cfa_offset = -1;
169 c->frame_info.lr_cfa_offset = -1;
170 c->frame_info.sp_cfa_offset = -1;
171 c->dwarf.loc[UNW_AARCH64_PC] = c->dwarf.loc[UNW_AARCH64_X30];
172 c->dwarf.loc[UNW_AARCH64_X30] = DWARF_NULL_LOC;
173 if (!DWARF_IS_NULL_LOC (c->dwarf.loc[UNW_AARCH64_PC]))
174 {
175 ret = dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_PC], &c->dwarf.ip);
176 if (ret < 0)
177 {
178 Debug (2, "failed to get pc from link register: %d\n", ret);
179 return ret;
180 }
181 Debug (2, "link register (x30) = 0x%016lx\n", c->dwarf.ip);
182 ret = 1;
183 }
184 else
185 c->dwarf.ip = 0;
186 }
187
188 return (c->dwarf.ip == 0) ? 0 : 1;
189 }
190