1/* libunwind - a platform-independent unwind library
2   Copyright (C) 2008 CodeSourcery
3   Copyright 2011 Linaro Limited
4   Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com>
5
6This file is part of libunwind.
7
8Permission is hereby granted, free of charge, to any person obtaining
9a copy of this software and associated documentation files (the
10"Software"), to deal in the Software without restriction, including
11without limitation the rights to use, copy, modify, merge, publish,
12distribute, sublicense, and/or sell copies of the Software, and to
13permit persons to whom the Software is furnished to do so, subject to
14the following conditions:
15
16The above copyright notice and this permission notice shall be
17included in all copies or substantial portions of the Software.
18
19THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
20EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
21MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
22NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
23LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
24OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
25WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.  */
26
27#include "unwind_i.h"
28#include "offsets.h"
29
30PROTECTED int
31unw_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 == 1)
50    {
51      /* Handle non-RT signal frame. */
52      c->sigcontext_format = SH_SCF_LINUX_SIGFRAME;
53      sc_addr = sp_addr;
54    }
55  else if (ret == 2)
56    {
57      /* Handle RT signal frame. */
58      c->sigcontext_format = SH_SCF_LINUX_RT_SIGFRAME;
59      sc_addr = sp_addr + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF;
60    }
61  else
62    return -UNW_EUNSPEC;
63
64  c->sigcontext_addr = sc_addr;
65
66  /* Update the dwarf cursor.
67     Set the location of the registers to the corresponding addresses of the
68     uc_mcontext / sigcontext structure contents.  */
69  c->dwarf.loc[UNW_SH_R0]  = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0);
70  c->dwarf.loc[UNW_SH_R1]  = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0);
71  c->dwarf.loc[UNW_SH_R2]  = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0);
72  c->dwarf.loc[UNW_SH_R3]  = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0);
73  c->dwarf.loc[UNW_SH_R4]  = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0);
74  c->dwarf.loc[UNW_SH_R5]  = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0);
75  c->dwarf.loc[UNW_SH_R6]  = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0);
76  c->dwarf.loc[UNW_SH_R7]  = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0);
77  c->dwarf.loc[UNW_SH_R8]  = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0);
78  c->dwarf.loc[UNW_SH_R9]  = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0);
79  c->dwarf.loc[UNW_SH_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0);
80  c->dwarf.loc[UNW_SH_R11] = DWARF_LOC (sc_addr + LINUX_SC_R11_OFF, 0);
81  c->dwarf.loc[UNW_SH_R12] = DWARF_LOC (sc_addr + LINUX_SC_R12_OFF, 0);
82  c->dwarf.loc[UNW_SH_R13] = DWARF_LOC (sc_addr + LINUX_SC_R13_OFF, 0);
83  c->dwarf.loc[UNW_SH_R14] = DWARF_LOC (sc_addr + LINUX_SC_R14_OFF, 0);
84  c->dwarf.loc[UNW_SH_R15] = DWARF_LOC (sc_addr + LINUX_SC_R15_OFF, 0);
85  c->dwarf.loc[UNW_SH_PR]  = DWARF_LOC (sc_addr + LINUX_SC_PR_OFF, 0);
86  c->dwarf.loc[UNW_SH_PC]  = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
87
88  /* Set SP/CFA and PC/IP.  */
89  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_SH_R15], &c->dwarf.cfa);
90  dwarf_get (&c->dwarf, c->dwarf.loc[UNW_SH_PC], &c->dwarf.ip);
91
92  c->dwarf.pi_valid = 0;
93
94  return 1;
95}
96
97PROTECTED int
98unw_step (unw_cursor_t *cursor)
99{
100  struct cursor *c = (struct cursor *) cursor;
101  int ret;
102
103  Debug (1, "(cursor=%p)\n", c);
104
105  if (unw_is_signal_frame (cursor))
106    return unw_handle_signal_frame (cursor);
107
108  ret = dwarf_step (&c->dwarf);
109
110  if (unlikely (ret == -UNW_ESTOPUNWIND))
111    return ret;
112
113  if (unlikely (ret < 0))
114    return 0;
115
116  return (c->dwarf.ip == 0) ? 0 : 1;
117}
118