1 /* libunwind - a platform-independent unwind library
2 Copyright (C) 2015 Imagination Technologies Limited
3 Copyright (C) 2008 CodeSourcery
4
5 This file is part of libunwind.
6
7 Permission is hereby granted, free of charge, to any person obtaining
8 a copy of this software and associated documentation files (the
9 "Software"), to deal in the Software without restriction, including
10 without limitation the rights to use, copy, modify, merge, publish,
11 distribute, sublicense, and/or sell copies of the Software, and to
12 permit persons to whom the Software is furnished to do so, subject to
13 the following conditions:
14
15 The above copyright notice and this permission notice shall be
16 included in all copies or substantial portions of the Software.
17
18 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
19 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
21 NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
22 LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
23 OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
24 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
25
26 #include "unwind_i.h"
27 #include "offsets.h"
28
29 static int
mips_handle_signal_frame(unw_cursor_t *cursor)30 mips_handle_signal_frame (unw_cursor_t *cursor)
31 {
32 struct cursor *c = (struct cursor *) cursor;
33 unw_word_t sc_addr, sp_addr = c->dwarf.cfa;
34 unw_word_t ra, fp;
35 int ret;
36
37 switch (unw_is_signal_frame (cursor)) {
38 case 1:
39 sc_addr = sp_addr + LINUX_SF_TRAMP_SIZE + sizeof (siginfo_t) +
40 LINUX_UC_MCONTEXT_OFF;
41 break;
42 case 2:
43 sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF;
44 break;
45 default:
46 return -UNW_EUNSPEC;
47 }
48
49 if (tdep_big_endian(c->dwarf.as))
50 sc_addr += 4;
51
52 c->sigcontext_addr = sc_addr;
53
54 /* Update the dwarf cursor. */
55 c->dwarf.loc[UNW_MIPS_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0);
56 c->dwarf.loc[UNW_MIPS_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0);
57 c->dwarf.loc[UNW_MIPS_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0);
58 c->dwarf.loc[UNW_MIPS_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0);
59 c->dwarf.loc[UNW_MIPS_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0);
60 c->dwarf.loc[UNW_MIPS_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0);
61 c->dwarf.loc[UNW_MIPS_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0);
62 c->dwarf.loc[UNW_MIPS_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0);
63 c->dwarf.loc[UNW_MIPS_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0);
64 c->dwarf.loc[UNW_MIPS_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0);
65 c->dwarf.loc[UNW_MIPS_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0);
66 c->dwarf.loc[UNW_MIPS_R11] = DWARF_LOC (sc_addr + LINUX_SC_R11_OFF, 0);
67 c->dwarf.loc[UNW_MIPS_R12] = DWARF_LOC (sc_addr + LINUX_SC_R12_OFF, 0);
68 c->dwarf.loc[UNW_MIPS_R13] = DWARF_LOC (sc_addr + LINUX_SC_R13_OFF, 0);
69 c->dwarf.loc[UNW_MIPS_R14] = DWARF_LOC (sc_addr + LINUX_SC_R14_OFF, 0);
70 c->dwarf.loc[UNW_MIPS_R15] = DWARF_LOC (sc_addr + LINUX_SC_R15_OFF, 0);
71 c->dwarf.loc[UNW_MIPS_R16] = DWARF_LOC (sc_addr + LINUX_SC_R16_OFF, 0);
72 c->dwarf.loc[UNW_MIPS_R17] = DWARF_LOC (sc_addr + LINUX_SC_R17_OFF, 0);
73 c->dwarf.loc[UNW_MIPS_R18] = DWARF_LOC (sc_addr + LINUX_SC_R18_OFF, 0);
74 c->dwarf.loc[UNW_MIPS_R19] = DWARF_LOC (sc_addr + LINUX_SC_R19_OFF, 0);
75 c->dwarf.loc[UNW_MIPS_R20] = DWARF_LOC (sc_addr + LINUX_SC_R20_OFF, 0);
76 c->dwarf.loc[UNW_MIPS_R21] = DWARF_LOC (sc_addr + LINUX_SC_R21_OFF, 0);
77 c->dwarf.loc[UNW_MIPS_R22] = DWARF_LOC (sc_addr + LINUX_SC_R22_OFF, 0);
78 c->dwarf.loc[UNW_MIPS_R23] = DWARF_LOC (sc_addr + LINUX_SC_R23_OFF, 0);
79 c->dwarf.loc[UNW_MIPS_R24] = DWARF_LOC (sc_addr + LINUX_SC_R24_OFF, 0);
80 c->dwarf.loc[UNW_MIPS_R25] = DWARF_LOC (sc_addr + LINUX_SC_R25_OFF, 0);
81 c->dwarf.loc[UNW_MIPS_R26] = DWARF_LOC (sc_addr + LINUX_SC_R26_OFF, 0);
82 c->dwarf.loc[UNW_MIPS_R27] = DWARF_LOC (sc_addr + LINUX_SC_R27_OFF, 0);
83 c->dwarf.loc[UNW_MIPS_R28] = DWARF_LOC (sc_addr + LINUX_SC_R28_OFF, 0);
84 c->dwarf.loc[UNW_MIPS_R29] = DWARF_LOC (sc_addr + LINUX_SC_R29_OFF, 0);
85 c->dwarf.loc[UNW_MIPS_R30] = DWARF_LOC (sc_addr + LINUX_SC_R30_OFF, 0);
86 c->dwarf.loc[UNW_MIPS_R31] = DWARF_LOC (sc_addr + LINUX_SC_R31_OFF, 0);
87 c->dwarf.loc[UNW_MIPS_PC] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0);
88
89 /* Set SP/CFA and PC/IP. */
90 dwarf_get (&c->dwarf, c->dwarf.loc[UNW_MIPS_R29], &c->dwarf.cfa);
91
92 if ((ret = dwarf_get(&c->dwarf, DWARF_LOC(sc_addr + LINUX_SC_PC_OFF, 0),
93 &c->dwarf.ip)) < 0)
94 return ret;
95
96 if ((ret = dwarf_get(&c->dwarf, DWARF_LOC(sc_addr + LINUX_SC_R31_OFF, 0),
97 &ra)) < 0)
98 return ret;
99 if ((ret = dwarf_get(&c->dwarf, DWARF_LOC(sc_addr + LINUX_SC_R30_OFF, 0),
100 &fp)) < 0)
101 return ret;
102
103 Debug (2, "SH (ip=0x%016llx, ra=0x%016llx, sp=0x%016llx, fp=0x%016llx)\n",
104 (unsigned long long)c->dwarf.ip, (unsigned long long)ra,
105 (unsigned long long)c->dwarf.cfa, (unsigned long long)fp);
106
107 c->dwarf.pi_valid = 0;
108 c->dwarf.use_prev_instr = 0;
109
110 return 1;
111 }
112
113
114
115 static inline
is_valid_fp_val(unw_word_t cfa_val, unw_word_t fp_val)116 int is_valid_fp_val(unw_word_t cfa_val, unw_word_t fp_val)
117 {
118 return fp_val > 0 && cfa_val > 0 && fp_val >cfa_val && (fp_val - cfa_val < 0x4000);
119 }
120
_step_n64(struct cursor *c)121 static int _step_n64(struct cursor *c)
122 {
123 #define FP_REG UNW_MIPS_R30
124 #define SP_REG UNW_MIPS_R29
125 #define RA_REG UNW_MIPS_R31
126
127 //TODO:handle plt entry
128 int ret;
129 unw_word_t current_fp_val = 0;
130 unw_word_t current_ra_val = 0;
131 unw_word_t current_sp_val = 0;
132 struct dwarf_loc up_fp_loc = DWARF_NULL_LOC;
133 struct dwarf_loc up_ra_loc = DWARF_NULL_LOC;
134
135 ret = dwarf_get (&c->dwarf, c->dwarf.loc[SP_REG], ¤t_sp_val);
136 if (ret < 0)
137 {
138 Debug (2, "returning %d [SP=0x%lx]\n", ret,
139 DWARF_GET_LOC (c->dwarf.loc[FP_REG]));
140 return ret;
141 }
142 ret = dwarf_get (&c->dwarf, c->dwarf.loc[FP_REG], ¤t_fp_val);
143 if (ret < 0)
144 {
145 Debug (2, "returning %d [FP=0x%lx]\n", ret,
146 DWARF_GET_LOC (c->dwarf.loc[FP_REG]));
147 return ret;
148 }
149 ret = dwarf_get (&c->dwarf, c->dwarf.loc[RA_REG], ¤t_ra_val);
150 if (ret < 0)
151 {
152 Debug (2, "returning %d [RA=0x%lx]\n", ret,
153 DWARF_GET_LOC (c->dwarf.loc[RA_REG]));
154 return ret;
155 }
156
157 Debug(2, "BEGIN GUESSING WITH SP:%p FP:%p CFA:%p at %p, RA:%p\n",
158 current_sp_val, current_fp_val, c->dwarf.cfa,
159 c->dwarf.ip, current_ra_val
160 );
161
162 if (current_fp_val == current_sp_val) {
163 // Don't adjust FP
164 up_fp_loc = c->dwarf.loc[FP_REG];
165 up_ra_loc = c->dwarf.loc[RA_REG];
166 } else if (is_valid_fp_val(c->dwarf.cfa, current_fp_val)) {
167 /* Heuristic to determine incorrect guess. For FP to be a
168 valid frame it needs to be above current CFA, but don't
169 let it go more than a little. Note that we can't deduce
170 anything about new FP (fp1) since it may not be a frame
171 pointer in the frame above. Just check we get the value. */
172 up_fp_loc = DWARF_MEM_LOC (c, current_fp_val+16);
173 up_ra_loc = DWARF_MEM_LOC (c, current_fp_val+24);
174 unw_word_t up_fp_val = 0;
175 ret = dwarf_get (&c->dwarf, up_fp_loc, &up_fp_val);
176 if (ret > 0 && is_valid_fp_val(current_fp_val, up_fp_val)) {
177 c->dwarf.loc[FP_REG] = up_fp_loc;
178 }
179 }
180
181 if (DWARF_IS_NULL_LOC (up_fp_loc))
182 {
183 ret = 0;
184 Debug (2, "NULL %%fp loc, returning %d\n", ret);
185 return ret;
186 }
187
188 c->dwarf.loc[UNW_MIPS_PC] = c->dwarf.loc[RA_REG];
189 c->dwarf.loc[RA_REG] = up_ra_loc;
190 c->dwarf.loc[SP_REG] = up_fp_loc;
191 c->dwarf.loc[FP_REG] = up_fp_loc;
192 c->dwarf.use_prev_instr = 1;
193
194 if (c->dwarf.ip == current_ra_val && current_fp_val == current_sp_val) {
195 // Backtrace stopped: frame did not save the PC
196 c->dwarf.ip = 0;
197 } else {
198 c->dwarf.ip = current_ra_val;
199 }
200 return (c->dwarf.ip == 0) ? 0 : 1;
201 }
202
203 int
unw_step(unw_cursor_t *cursor)204 unw_step (unw_cursor_t *cursor)
205 {
206 struct cursor *c = (struct cursor *) cursor;
207 int ret;
208
209 ret = mips_handle_signal_frame (cursor);
210 if (ret < 0)
211 /* Not a signal frame, try DWARF-based unwinding. */
212 ret = dwarf_step (&c->dwarf);
213
214 if (unlikely (ret == -UNW_ESTOPUNWIND))
215 return ret;
216
217 if (unlikely (ret < 0))
218 {
219 #if _MIPS_SIM == _ABI64
220 return _step_n64(c);
221 #else
222 return ret;
223 #endif
224 }
225
226 return (c->dwarf.ip == 0) ? 0 : 1;
227 }
228