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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   /* Check if this is a signal frame. */
116   if (unw_is_signal_frame (cursor))
117     /* ANDROID support update. */
118     ret = unw_handle_signal_frame (cursor);
119     /* End ANDROID update. */
120 
121   /* ANDROID support update. */
122   if (ret < 0)
123     {
124       ret = dwarf_step (&c->dwarf);
125       Debug(1, "dwarf_step()=%d\n", ret);
126     }
127 
128   if (ret < 0 && c->dwarf.frame == 0)
129     {
130       /* If this is the first frame, the code may be executing garbage
131        * in the middle of nowhere. In this case, try using the lr as
132        * the pc.
133        */
134       unw_word_t lr;
135       if (dwarf_get(&c->dwarf, c->dwarf.loc[UNW_AARCH64_X30], &lr) >= 0)
136         {
137           if (lr != c->dwarf.ip)
138             {
139               ret = 1;
140               c->dwarf.ip = lr;
141             }
142         }
143     }
144   /* End ANDROID update. */
145 
146   if (ret >= 0)
147     {
148       c->dwarf.frame++;
149       if (c->dwarf.ip >= 4)
150         c->dwarf.ip -= 4;
151     }
152 
153   if (unlikely (ret == -UNW_ESTOPUNWIND))
154     return ret;
155 
156   if (unlikely (ret < 0))
157     return 0;
158 
159   return (c->dwarf.ip == 0) ? 0 : 1;
160 }
161