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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
5ea84154 JO |
2 | #include <linux/compiler.h> |
3 | #include <elfutils/libdw.h> | |
4 | #include <elfutils/libdwfl.h> | |
5 | #include <inttypes.h> | |
6 | #include <errno.h> | |
84f5d36f | 7 | #include "debug.h" |
4a3cec84 | 8 | #include "dso.h" |
5ea84154 JO |
9 | #include "unwind.h" |
10 | #include "unwind-libdw.h" | |
11 | #include "machine.h" | |
1101f69a | 12 | #include "map.h" |
daecf9e0 | 13 | #include "symbol.h" |
5ea84154 | 14 | #include "thread.h" |
d944c4ee | 15 | #include <linux/types.h> |
7f7c536f | 16 | #include <linux/zalloc.h> |
5ea84154 JO |
17 | #include "event.h" |
18 | #include "perf_regs.h" | |
8bd508b0 | 19 | #include "callchain.h" |
5ea84154 JO |
20 | |
21 | static char *debuginfo_path; | |
22 | ||
23 | static const Dwfl_Callbacks offline_callbacks = { | |
24 | .find_debuginfo = dwfl_standard_find_debuginfo, | |
25 | .debuginfo_path = &debuginfo_path, | |
26 | .section_address = dwfl_offline_section_address, | |
27 | }; | |
28 | ||
29 | static int __report_module(struct addr_location *al, u64 ip, | |
30 | struct unwind_info *ui) | |
31 | { | |
32 | Dwfl_Module *mod; | |
33 | struct dso *dso = NULL; | |
4546263d ACM |
34 | /* |
35 | * Some callers will use al->sym, so we can't just use the | |
36 | * cheaper thread__find_map() here. | |
37 | */ | |
38 | thread__find_symbol(ui->thread, PERF_RECORD_MISC_USER, ip, al); | |
5ea84154 JO |
39 | |
40 | if (al->map) | |
41 | dso = al->map->dso; | |
42 | ||
43 | if (!dso) | |
44 | return 0; | |
45 | ||
46 | mod = dwfl_addrmodule(ui->dwfl, ip); | |
2538b9e2 MW |
47 | if (mod) { |
48 | Dwarf_Addr s; | |
49 | ||
50 | dwfl_module_info(mod, NULL, &s, NULL, NULL, NULL, NULL, NULL); | |
1fe627da | 51 | if (s != al->map->start - al->map->pgoff) |
2538b9e2 MW |
52 | mod = 0; |
53 | } | |
54 | ||
5ea84154 JO |
55 | if (!mod) |
56 | mod = dwfl_report_elf(ui->dwfl, dso->short_name, | |
1fe627da | 57 | (dso->symsrc_filename ? dso->symsrc_filename : dso->long_name), -1, al->map->start - al->map->pgoff, |
5ea84154 JO |
58 | false); |
59 | ||
60 | return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1; | |
61 | } | |
62 | ||
63 | static int report_module(u64 ip, struct unwind_info *ui) | |
64 | { | |
65 | struct addr_location al; | |
66 | ||
67 | return __report_module(&al, ip, ui); | |
68 | } | |
69 | ||
8bd508b0 JO |
70 | /* |
71 | * Store all entries within entries array, | |
72 | * we will process it after we finish unwind. | |
73 | */ | |
5ea84154 JO |
74 | static int entry(u64 ip, struct unwind_info *ui) |
75 | ||
76 | { | |
8bd508b0 | 77 | struct unwind_entry *e = &ui->entries[ui->idx++]; |
5ea84154 JO |
78 | struct addr_location al; |
79 | ||
80 | if (__report_module(&al, ip, ui)) | |
81 | return -1; | |
82 | ||
c1529738 | 83 | e->ip = ip; |
f2eaea09 | 84 | e->ms.maps = al.maps; |
c1529738 ACM |
85 | e->ms.map = al.map; |
86 | e->ms.sym = al.sym; | |
5ea84154 JO |
87 | |
88 | pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n", | |
89 | al.sym ? al.sym->name : "''", | |
90 | ip, | |
91 | al.map ? al.map->map_ip(al.map, ip) : (u64) 0); | |
8bd508b0 | 92 | return 0; |
5ea84154 JO |
93 | } |
94 | ||
95 | static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp) | |
96 | { | |
97 | /* We want only single thread to be processed. */ | |
98 | if (*thread_argp != NULL) | |
99 | return 0; | |
100 | ||
101 | *thread_argp = arg; | |
102 | return dwfl_pid(dwfl); | |
103 | } | |
104 | ||
105 | static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr, | |
106 | Dwarf_Word *data) | |
107 | { | |
108 | struct addr_location al; | |
109 | ssize_t size; | |
110 | ||
71a84b5a | 111 | if (!thread__find_map(ui->thread, PERF_RECORD_MISC_USER, addr, &al)) { |
5ea84154 JO |
112 | pr_debug("unwind: no map for %lx\n", (unsigned long)addr); |
113 | return -1; | |
114 | } | |
115 | ||
116 | if (!al.map->dso) | |
117 | return -1; | |
118 | ||
119 | size = dso__data_read_addr(al.map->dso, al.map, ui->machine, | |
120 | addr, (u8 *) data, sizeof(*data)); | |
121 | ||
122 | return !(size == sizeof(*data)); | |
123 | } | |
124 | ||
125 | static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result, | |
126 | void *arg) | |
127 | { | |
128 | struct unwind_info *ui = arg; | |
129 | struct stack_dump *stack = &ui->sample->user_stack; | |
130 | u64 start, end; | |
131 | int offset; | |
132 | int ret; | |
133 | ||
134 | ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP); | |
135 | if (ret) | |
136 | return false; | |
137 | ||
138 | end = start + stack->size; | |
139 | ||
140 | /* Check overflow. */ | |
141 | if (addr + sizeof(Dwarf_Word) < addr) | |
142 | return false; | |
143 | ||
144 | if (addr < start || addr + sizeof(Dwarf_Word) > end) { | |
145 | ret = access_dso_mem(ui, addr, result); | |
146 | if (ret) { | |
147 | pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range" | |
148 | " 0x%" PRIx64 "-0x%" PRIx64 "\n", | |
149 | addr, start, end); | |
150 | return false; | |
151 | } | |
152 | return true; | |
153 | } | |
154 | ||
155 | offset = addr - start; | |
156 | *result = *(Dwarf_Word *)&stack->data[offset]; | |
157 | pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n", | |
158 | addr, (unsigned long)*result, offset); | |
159 | return true; | |
160 | } | |
161 | ||
162 | static const Dwfl_Thread_Callbacks callbacks = { | |
163 | .next_thread = next_thread, | |
164 | .memory_read = memory_read, | |
165 | .set_initial_registers = libdw__arch_set_initial_registers, | |
166 | }; | |
167 | ||
168 | static int | |
169 | frame_callback(Dwfl_Frame *state, void *arg) | |
170 | { | |
171 | struct unwind_info *ui = arg; | |
172 | Dwarf_Addr pc; | |
1982ad48 | 173 | bool isactivation; |
5ea84154 | 174 | |
9126cbba MW |
175 | if (!dwfl_frame_pc(state, &pc, NULL)) { |
176 | pr_err("%s", dwfl_errmsg(-1)); | |
177 | return DWARF_CB_ABORT; | |
178 | } | |
179 | ||
180 | // report the module before we query for isactivation | |
181 | report_module(pc, ui); | |
182 | ||
1982ad48 | 183 | if (!dwfl_frame_pc(state, &pc, &isactivation)) { |
5ea84154 JO |
184 | pr_err("%s", dwfl_errmsg(-1)); |
185 | return DWARF_CB_ABORT; | |
186 | } | |
187 | ||
1982ad48 MW |
188 | if (!isactivation) |
189 | --pc; | |
190 | ||
5ea84154 JO |
191 | return entry(pc, ui) || !(--ui->max_stack) ? |
192 | DWARF_CB_ABORT : DWARF_CB_OK; | |
193 | } | |
194 | ||
195 | int unwind__get_entries(unwind_entry_cb_t cb, void *arg, | |
dd8c17a5 | 196 | struct thread *thread, |
5ea84154 JO |
197 | struct perf_sample *data, |
198 | int max_stack) | |
199 | { | |
8bd508b0 | 200 | struct unwind_info *ui, ui_buf = { |
5ea84154 JO |
201 | .sample = data, |
202 | .thread = thread, | |
fe87797d | 203 | .machine = thread->maps->machine, |
5ea84154 JO |
204 | .cb = cb, |
205 | .arg = arg, | |
206 | .max_stack = max_stack, | |
207 | }; | |
208 | Dwarf_Word ip; | |
8bd508b0 | 209 | int err = -EINVAL, i; |
5ea84154 JO |
210 | |
211 | if (!data->user_regs.regs) | |
212 | return -EINVAL; | |
213 | ||
8bd508b0 JO |
214 | ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack); |
215 | if (!ui) | |
216 | return -ENOMEM; | |
217 | ||
218 | *ui = ui_buf; | |
219 | ||
220 | ui->dwfl = dwfl_begin(&offline_callbacks); | |
221 | if (!ui->dwfl) | |
5ea84154 JO |
222 | goto out; |
223 | ||
224 | err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); | |
225 | if (err) | |
226 | goto out; | |
227 | ||
8bd508b0 | 228 | err = report_module(ip, ui); |
5ea84154 JO |
229 | if (err) |
230 | goto out; | |
231 | ||
555fc3b1 MV |
232 | err = !dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui); |
233 | if (err) | |
5ea84154 JO |
234 | goto out; |
235 | ||
8bd508b0 | 236 | err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); |
5ea84154 | 237 | |
5ea0416f | 238 | if (err && ui->max_stack != max_stack) |
5ea84154 JO |
239 | err = 0; |
240 | ||
8bd508b0 JO |
241 | /* |
242 | * Display what we got based on the order setup. | |
243 | */ | |
244 | for (i = 0; i < ui->idx && !err; i++) { | |
245 | int j = i; | |
246 | ||
247 | if (callchain_param.order == ORDER_CALLER) | |
248 | j = ui->idx - i - 1; | |
249 | ||
250 | err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0; | |
251 | } | |
252 | ||
5ea84154 JO |
253 | out: |
254 | if (err) | |
255 | pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1)); | |
256 | ||
8bd508b0 JO |
257 | dwfl_end(ui->dwfl); |
258 | free(ui); | |
5ea84154 JO |
259 | return 0; |
260 | } |