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12#include <inttypes.h>
13#include <dwarf.h>
14#include <elfutils/libdwfl.h>
15
16#include "util/thread.h"
17#include "util/callchain.h"
18#include "util/debug.h"
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33static char *debuginfo_path;
34
35static const Dwfl_Callbacks offline_callbacks = {
36 .debuginfo_path = &debuginfo_path,
37 .find_debuginfo = dwfl_standard_find_debuginfo,
38 .section_address = dwfl_offline_section_address,
39};
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45
46static int check_return_reg(int ra_regno, Dwarf_Frame *frame)
47{
48 Dwarf_Op ops_mem[2];
49 Dwarf_Op dummy;
50 Dwarf_Op *ops = &dummy;
51 size_t nops;
52 int result;
53
54 result = dwarf_frame_register(frame, ra_regno, ops_mem, &ops, &nops);
55 if (result < 0) {
56 pr_debug("dwarf_frame_register() %s\n", dwarf_errmsg(-1));
57 return -1;
58 }
59
60
61
62
63 if (nops != 0 || ops != NULL)
64 return 0;
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70 result = dwarf_frame_cfa(frame, &ops, &nops);
71 if (result < 0) {
72 pr_debug("dwarf_frame_cfa() returns %d, %s\n", result,
73 dwarf_errmsg(-1));
74 return -1;
75 }
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77
78
79
80 if (nops == 1 && ops[0].atom == DW_OP_bregx && ops[0].number == 1 &&
81 ops[0].number2 == 0)
82 return 1;
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86
87 return 2;
88}
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92
93static Dwarf_Frame *get_eh_frame(Dwfl_Module *mod, Dwarf_Addr pc)
94{
95 int result;
96 Dwarf_Addr bias;
97 Dwarf_CFI *cfi;
98 Dwarf_Frame *frame;
99
100 cfi = dwfl_module_eh_cfi(mod, &bias);
101 if (!cfi) {
102 pr_debug("%s(): no CFI - %s\n", __func__, dwfl_errmsg(-1));
103 return NULL;
104 }
105
106 result = dwarf_cfi_addrframe(cfi, pc, &frame);
107 if (result) {
108 pr_debug("%s(): %s\n", __func__, dwfl_errmsg(-1));
109 return NULL;
110 }
111
112 return frame;
113}
114
115
116
117
118static Dwarf_Frame *get_dwarf_frame(Dwfl_Module *mod, Dwarf_Addr pc)
119{
120 Dwarf_CFI *cfi;
121 Dwarf_Addr bias;
122 Dwarf_Frame *frame;
123 int result;
124
125 cfi = dwfl_module_dwarf_cfi(mod, &bias);
126 if (!cfi) {
127 pr_debug("%s(): no CFI - %s\n", __func__, dwfl_errmsg(-1));
128 return NULL;
129 }
130
131 result = dwarf_cfi_addrframe(cfi, pc, &frame);
132 if (result) {
133 pr_debug("%s(): %s\n", __func__, dwfl_errmsg(-1));
134 return NULL;
135 }
136
137 return frame;
138}
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147
148static int check_return_addr(const char *exec_file, Dwarf_Addr pc)
149{
150 int rc = -1;
151 Dwfl *dwfl;
152 Dwfl_Module *mod;
153 Dwarf_Frame *frame;
154 int ra_regno;
155 Dwarf_Addr start = pc;
156 Dwarf_Addr end = pc;
157 bool signalp;
158
159 dwfl = dwfl_begin(&offline_callbacks);
160 if (!dwfl) {
161 pr_debug("dwfl_begin() failed: %s\n", dwarf_errmsg(-1));
162 return -1;
163 }
164
165 if (dwfl_report_offline(dwfl, "", exec_file, -1) == NULL) {
166 pr_debug("dwfl_report_offline() failed %s\n", dwarf_errmsg(-1));
167 goto out;
168 }
169
170 mod = dwfl_addrmodule(dwfl, pc);
171 if (!mod) {
172 pr_debug("dwfl_addrmodule() failed, %s\n", dwarf_errmsg(-1));
173 goto out;
174 }
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179
180 frame = get_eh_frame(mod, pc);
181 if (!frame) {
182 frame = get_dwarf_frame(mod, pc);
183 if (!frame)
184 goto out;
185 }
186
187 ra_regno = dwarf_frame_info(frame, &start, &end, &signalp);
188 if (ra_regno < 0) {
189 pr_debug("Return address register unavailable: %s\n",
190 dwarf_errmsg(-1));
191 goto out;
192 }
193
194 rc = check_return_reg(ra_regno, frame);
195
196out:
197 dwfl_end(dwfl);
198 return rc;
199}
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224int arch_skip_callchain_idx(struct machine *machine, struct thread *thread,
225 struct ip_callchain *chain)
226{
227 struct addr_location al;
228 struct dso *dso = NULL;
229 int rc;
230 u64 ip;
231 u64 skip_slot = -1;
232
233 if (chain->nr < 3)
234 return skip_slot;
235
236 ip = chain->ips[2];
237
238 thread__find_addr_location(thread, machine, PERF_RECORD_MISC_USER,
239 MAP__FUNCTION, ip, &al);
240
241 if (al.map)
242 dso = al.map->dso;
243
244 if (!dso) {
245 pr_debug("%" PRIx64 " dso is NULL\n", ip);
246 return skip_slot;
247 }
248
249 rc = check_return_addr(dso->long_name, ip);
250
251 pr_debug("DSO %s, nr %" PRIx64 ", ip 0x%" PRIx64 "rc %d\n",
252 dso->long_name, chain->nr, ip, rc);
253
254 if (rc == 0) {
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257
258 skip_slot = 2;
259 } else if (rc == 2) {
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264 skip_slot = 3;
265 }
266 return skip_slot;
267}
268