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 PROTECTED int
unw_handle_signal_frame(unw_cursor_t * cursor)31 unw_handle_signal_frame (unw_cursor_t *cursor)
32 {
33   struct cursor *c = (struct cursor *) cursor;
34   int ret;
35   unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa;
36   struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0);
37 
38   if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0)
39     return -UNW_EUNSPEC;
40 
41   ret = unw_is_signal_frame (cursor);
42   Debug(1, "unw_is_signal_frame()=%d\n", ret);
43 
44   /* Save the SP and PC to be able to return execution at this point
45      later in time (unw_resume).  */
46   c->sigcontext_sp = c->dwarf.cfa;
47   c->sigcontext_pc = c->dwarf.ip;
48 
49   if (ret)
50     {
51       c->sigcontext_format = AARCH64_SCF_LINUX_RT_SIGFRAME;
52       sc_addr = sp_addr + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
53     }
54   else
55     return -UNW_EUNSPEC;
56 
57   c->sigcontext_addr = sc_addr;
58 
59   /* Update the dwarf cursor.
60      Set the location of the registers to the corresponding addresses of the
61      uc_mcontext / sigcontext structure contents.  */
62   c->dwarf.loc[UNW_AARCH64_X0]  = DWARF_LOC (sc_addr + LINUX_SC_X0_OFF, 0);
63   c->dwarf.loc[UNW_AARCH64_X1]  = DWARF_LOC (sc_addr + LINUX_SC_X1_OFF, 0);
64   c->dwarf.loc[UNW_AARCH64_X2]  = DWARF_LOC (sc_addr + LINUX_SC_X2_OFF, 0);
65   c->dwarf.loc[UNW_AARCH64_X3]  = DWARF_LOC (sc_addr + LINUX_SC_X3_OFF, 0);
66   c->dwarf.loc[UNW_AARCH64_X4]  = DWARF_LOC (sc_addr + LINUX_SC_X4_OFF, 0);
67   c->dwarf.loc[UNW_AARCH64_X5]  = DWARF_LOC (sc_addr + LINUX_SC_X5_OFF, 0);
68   c->dwarf.loc[UNW_AARCH64_X6]  = DWARF_LOC (sc_addr + LINUX_SC_X6_OFF, 0);
69   c->dwarf.loc[UNW_AARCH64_X7]  = DWARF_LOC (sc_addr + LINUX_SC_X7_OFF, 0);
70   c->dwarf.loc[UNW_AARCH64_X8]  = DWARF_LOC (sc_addr + LINUX_SC_X8_OFF, 0);
71   c->dwarf.loc[UNW_AARCH64_X9]  = DWARF_LOC (sc_addr + LINUX_SC_X9_OFF, 0);
72   c->dwarf.loc[UNW_AARCH64_X10] = DWARF_LOC (sc_addr + LINUX_SC_X10_OFF, 0);
73   c->dwarf.loc[UNW_AARCH64_X11] = DWARF_LOC (sc_addr + LINUX_SC_X11_OFF, 0);
74   c->dwarf.loc[UNW_AARCH64_X12] = DWARF_LOC (sc_addr + LINUX_SC_X12_OFF, 0);
75   c->dwarf.loc[UNW_AARCH64_X13] = DWARF_LOC (sc_addr + LINUX_SC_X13_OFF, 0);
76   c->dwarf.loc[UNW_AARCH64_X14] = DWARF_LOC (sc_addr + LINUX_SC_X14_OFF, 0);
77   c->dwarf.loc[UNW_AARCH64_X15] = DWARF_LOC (sc_addr + LINUX_SC_X15_OFF, 0);
78   c->dwarf.loc[UNW_AARCH64_X16] = DWARF_LOC (sc_addr + LINUX_SC_X16_OFF, 0);
79   c->dwarf.loc[UNW_AARCH64_X17] = DWARF_LOC (sc_addr + LINUX_SC_X17_OFF, 0);
80   c->dwarf.loc[UNW_AARCH64_X18] = DWARF_LOC (sc_addr + LINUX_SC_X18_OFF, 0);
81   c->dwarf.loc[UNW_AARCH64_X19] = DWARF_LOC (sc_addr + LINUX_SC_X19_OFF, 0);
82   c->dwarf.loc[UNW_AARCH64_X20] = DWARF_LOC (sc_addr + LINUX_SC_X20_OFF, 0);
83   c->dwarf.loc[UNW_AARCH64_X21] = DWARF_LOC (sc_addr + LINUX_SC_X21_OFF, 0);
84   c->dwarf.loc[UNW_AARCH64_X22] = DWARF_LOC (sc_addr + LINUX_SC_X22_OFF, 0);
85   c->dwarf.loc[UNW_AARCH64_X23] = DWARF_LOC (sc_addr + LINUX_SC_X23_OFF, 0);
86   c->dwarf.loc[UNW_AARCH64_X24] = DWARF_LOC (sc_addr + LINUX_SC_X24_OFF, 0);
87   c->dwarf.loc[UNW_AARCH64_X25] = DWARF_LOC (sc_addr + LINUX_SC_X25_OFF, 0);
88   c->dwarf.loc[UNW_AARCH64_X26] = DWARF_LOC (sc_addr + LINUX_SC_X26_OFF, 0);
89   c->dwarf.loc[UNW_AARCH64_X27] = DWARF_LOC (sc_addr + LINUX_SC_X27_OFF, 0);
90   c->dwarf.loc[UNW_AARCH64_X28] = DWARF_LOC (sc_addr + LINUX_SC_X28_OFF, 0);
91   c->dwarf.loc[UNW_AARCH64_X29] = DWARF_LOC (sc_addr + LINUX_SC_X29_OFF, 0);
92   c->dwarf.loc[UNW_AARCH64_X30] = DWARF_LOC (sc_addr + LINUX_SC_X30_OFF, 0);
93   c->dwarf.loc[UNW_AARCH64_SP]  = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0);
94   c->dwarf.loc[UNW_AARCH64_PC]  = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
95   c->dwarf.loc[UNW_AARCH64_PSTATE]  = DWARF_LOC (sc_addr + LINUX_SC_PSTATE_OFF, 0);
96 
97   /* Set SP/CFA and PC/IP.  */
98   dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_SP], &c->dwarf.cfa);
99   dwarf_get (&c->dwarf, c->dwarf.loc[UNW_AARCH64_PC], &c->dwarf.ip);
100 
101   c->dwarf.pi_valid = 0;
102 
103   return 1;
104 }
105 
106 PROTECTED int
unw_step(unw_cursor_t * cursor)107 unw_step (unw_cursor_t *cursor)
108 {
109   struct cursor *c = (struct cursor *) cursor;
110   int ret = -UNW_ENOINFO;
111 
112   Debug (1, "(cursor=%p, ip=0x%016lx, cfa=0x%016lx))\n",
113 	 c, c->dwarf.ip, c->dwarf.cfa);
114 
115   unw_word_t old_ip = c->dwarf.ip;
116   unw_word_t old_cfa = c->dwarf.cfa;
117 
118   /* Check if this is a signal frame. */
119   if (unw_is_signal_frame (cursor))
120     /* ANDROID support update. */
121     ret = unw_handle_signal_frame (cursor);
122     /* End ANDROID update. */
123 
124   /* ANDROID support update. */
125   if (ret < 0)
126     {
127       ret = dwarf_step (&c->dwarf);
128       Debug(1, "dwarf_step()=%d\n", ret);
129     }
130 
131   if (ret < 0 && c->dwarf.frame == 0)
132     {
133       /* If this is the first frame, the code may be executing garbage
134        * in the middle of nowhere. In this case, try using the lr as
135        * the pc.
136        */
137       unw_word_t lr;
138       if (dwarf_get(&c->dwarf, c->dwarf.loc[UNW_AARCH64_X30], &lr) >= 0)
139         {
140           if (lr != c->dwarf.ip)
141             {
142               ret = 1;
143               c->dwarf.ip = lr;
144             }
145         }
146     }
147   /* End ANDROID update. */
148 
149   if (ret >= 0)
150     {
151       if (c->dwarf.ip >= 4)
152         c->dwarf.ip -= 4;
153       /* If the decode yields the exact same ip/cfa as before, then indicate
154          the unwind is complete. */
155       if (c->dwarf.ip == old_ip && c->dwarf.cfa == old_cfa)
156         {
157           Dprintf ("%s: ip and cfa unchanged; stopping here (ip=0x%lx)\n",
158                    __FUNCTION__, (long) c->dwarf.ip);
159           return -UNW_EBADFRAME;
160         }
161       c->dwarf.frame++;
162     }
163 
164   if (unlikely (ret == -UNW_ESTOPUNWIND))
165     return ret;
166 
167   if (unlikely (ret <= 0))
168     return 0;
169 
170   return (c->dwarf.ip == 0) ? 0 : 1;
171 }
172