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5ea84154 JO |
1 | #include <linux/compiler.h> |
2 | #include <elfutils/libdw.h> | |
3 | #include <elfutils/libdwfl.h> | |
4 | #include <inttypes.h> | |
5 | #include <errno.h> | |
84f5d36f | 6 | #include "debug.h" |
5ea84154 JO |
7 | #include "unwind.h" |
8 | #include "unwind-libdw.h" | |
9 | #include "machine.h" | |
10 | #include "thread.h" | |
d944c4ee | 11 | #include <linux/types.h> |
5ea84154 JO |
12 | #include "event.h" |
13 | #include "perf_regs.h" | |
8bd508b0 | 14 | #include "callchain.h" |
5ea84154 JO |
15 | |
16 | static char *debuginfo_path; | |
17 | ||
18 | static const Dwfl_Callbacks offline_callbacks = { | |
19 | .find_debuginfo = dwfl_standard_find_debuginfo, | |
20 | .debuginfo_path = &debuginfo_path, | |
21 | .section_address = dwfl_offline_section_address, | |
22 | }; | |
23 | ||
24 | static int __report_module(struct addr_location *al, u64 ip, | |
25 | struct unwind_info *ui) | |
26 | { | |
27 | Dwfl_Module *mod; | |
28 | struct dso *dso = NULL; | |
29 | ||
bb871a9c | 30 | thread__find_addr_location(ui->thread, |
5ea84154 JO |
31 | PERF_RECORD_MISC_USER, |
32 | MAP__FUNCTION, ip, al); | |
33 | ||
34 | if (al->map) | |
35 | dso = al->map->dso; | |
36 | ||
37 | if (!dso) | |
38 | return 0; | |
39 | ||
40 | mod = dwfl_addrmodule(ui->dwfl, ip); | |
41 | if (!mod) | |
42 | mod = dwfl_report_elf(ui->dwfl, dso->short_name, | |
43 | dso->long_name, -1, al->map->start, | |
44 | false); | |
45 | ||
46 | return mod && dwfl_addrmodule(ui->dwfl, ip) == mod ? 0 : -1; | |
47 | } | |
48 | ||
49 | static int report_module(u64 ip, struct unwind_info *ui) | |
50 | { | |
51 | struct addr_location al; | |
52 | ||
53 | return __report_module(&al, ip, ui); | |
54 | } | |
55 | ||
8bd508b0 JO |
56 | /* |
57 | * Store all entries within entries array, | |
58 | * we will process it after we finish unwind. | |
59 | */ | |
5ea84154 JO |
60 | static int entry(u64 ip, struct unwind_info *ui) |
61 | ||
62 | { | |
8bd508b0 | 63 | struct unwind_entry *e = &ui->entries[ui->idx++]; |
5ea84154 JO |
64 | struct addr_location al; |
65 | ||
66 | if (__report_module(&al, ip, ui)) | |
67 | return -1; | |
68 | ||
8bd508b0 JO |
69 | e->ip = ip; |
70 | e->map = al.map; | |
71 | e->sym = al.sym; | |
5ea84154 JO |
72 | |
73 | pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n", | |
74 | al.sym ? al.sym->name : "''", | |
75 | ip, | |
76 | al.map ? al.map->map_ip(al.map, ip) : (u64) 0); | |
8bd508b0 | 77 | return 0; |
5ea84154 JO |
78 | } |
79 | ||
80 | static pid_t next_thread(Dwfl *dwfl, void *arg, void **thread_argp) | |
81 | { | |
82 | /* We want only single thread to be processed. */ | |
83 | if (*thread_argp != NULL) | |
84 | return 0; | |
85 | ||
86 | *thread_argp = arg; | |
87 | return dwfl_pid(dwfl); | |
88 | } | |
89 | ||
90 | static int access_dso_mem(struct unwind_info *ui, Dwarf_Addr addr, | |
91 | Dwarf_Word *data) | |
92 | { | |
93 | struct addr_location al; | |
94 | ssize_t size; | |
95 | ||
bb871a9c | 96 | thread__find_addr_map(ui->thread, PERF_RECORD_MISC_USER, |
5ea84154 JO |
97 | MAP__FUNCTION, addr, &al); |
98 | if (!al.map) { | |
99 | pr_debug("unwind: no map for %lx\n", (unsigned long)addr); | |
100 | return -1; | |
101 | } | |
102 | ||
103 | if (!al.map->dso) | |
104 | return -1; | |
105 | ||
106 | size = dso__data_read_addr(al.map->dso, al.map, ui->machine, | |
107 | addr, (u8 *) data, sizeof(*data)); | |
108 | ||
109 | return !(size == sizeof(*data)); | |
110 | } | |
111 | ||
112 | static bool memory_read(Dwfl *dwfl __maybe_unused, Dwarf_Addr addr, Dwarf_Word *result, | |
113 | void *arg) | |
114 | { | |
115 | struct unwind_info *ui = arg; | |
116 | struct stack_dump *stack = &ui->sample->user_stack; | |
117 | u64 start, end; | |
118 | int offset; | |
119 | int ret; | |
120 | ||
121 | ret = perf_reg_value(&start, &ui->sample->user_regs, PERF_REG_SP); | |
122 | if (ret) | |
123 | return false; | |
124 | ||
125 | end = start + stack->size; | |
126 | ||
127 | /* Check overflow. */ | |
128 | if (addr + sizeof(Dwarf_Word) < addr) | |
129 | return false; | |
130 | ||
131 | if (addr < start || addr + sizeof(Dwarf_Word) > end) { | |
132 | ret = access_dso_mem(ui, addr, result); | |
133 | if (ret) { | |
134 | pr_debug("unwind: access_mem 0x%" PRIx64 " not inside range" | |
135 | " 0x%" PRIx64 "-0x%" PRIx64 "\n", | |
136 | addr, start, end); | |
137 | return false; | |
138 | } | |
139 | return true; | |
140 | } | |
141 | ||
142 | offset = addr - start; | |
143 | *result = *(Dwarf_Word *)&stack->data[offset]; | |
144 | pr_debug("unwind: access_mem addr 0x%" PRIx64 ", val %lx, offset %d\n", | |
145 | addr, (unsigned long)*result, offset); | |
146 | return true; | |
147 | } | |
148 | ||
149 | static const Dwfl_Thread_Callbacks callbacks = { | |
150 | .next_thread = next_thread, | |
151 | .memory_read = memory_read, | |
152 | .set_initial_registers = libdw__arch_set_initial_registers, | |
153 | }; | |
154 | ||
155 | static int | |
156 | frame_callback(Dwfl_Frame *state, void *arg) | |
157 | { | |
158 | struct unwind_info *ui = arg; | |
159 | Dwarf_Addr pc; | |
160 | ||
161 | if (!dwfl_frame_pc(state, &pc, NULL)) { | |
162 | pr_err("%s", dwfl_errmsg(-1)); | |
163 | return DWARF_CB_ABORT; | |
164 | } | |
165 | ||
166 | return entry(pc, ui) || !(--ui->max_stack) ? | |
167 | DWARF_CB_ABORT : DWARF_CB_OK; | |
168 | } | |
169 | ||
170 | int unwind__get_entries(unwind_entry_cb_t cb, void *arg, | |
dd8c17a5 | 171 | struct thread *thread, |
5ea84154 JO |
172 | struct perf_sample *data, |
173 | int max_stack) | |
174 | { | |
8bd508b0 | 175 | struct unwind_info *ui, ui_buf = { |
5ea84154 JO |
176 | .sample = data, |
177 | .thread = thread, | |
dd8c17a5 | 178 | .machine = thread->mg->machine, |
5ea84154 JO |
179 | .cb = cb, |
180 | .arg = arg, | |
181 | .max_stack = max_stack, | |
182 | }; | |
183 | Dwarf_Word ip; | |
8bd508b0 | 184 | int err = -EINVAL, i; |
5ea84154 JO |
185 | |
186 | if (!data->user_regs.regs) | |
187 | return -EINVAL; | |
188 | ||
8bd508b0 JO |
189 | ui = zalloc(sizeof(ui_buf) + sizeof(ui_buf.entries[0]) * max_stack); |
190 | if (!ui) | |
191 | return -ENOMEM; | |
192 | ||
193 | *ui = ui_buf; | |
194 | ||
195 | ui->dwfl = dwfl_begin(&offline_callbacks); | |
196 | if (!ui->dwfl) | |
5ea84154 JO |
197 | goto out; |
198 | ||
199 | err = perf_reg_value(&ip, &data->user_regs, PERF_REG_IP); | |
200 | if (err) | |
201 | goto out; | |
202 | ||
8bd508b0 | 203 | err = report_module(ip, ui); |
5ea84154 JO |
204 | if (err) |
205 | goto out; | |
206 | ||
8bd508b0 | 207 | if (!dwfl_attach_state(ui->dwfl, EM_NONE, thread->tid, &callbacks, ui)) |
5ea84154 JO |
208 | goto out; |
209 | ||
8bd508b0 | 210 | err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); |
5ea84154 | 211 | |
8bd508b0 | 212 | if (err && !ui->max_stack) |
5ea84154 JO |
213 | err = 0; |
214 | ||
8bd508b0 JO |
215 | /* |
216 | * Display what we got based on the order setup. | |
217 | */ | |
218 | for (i = 0; i < ui->idx && !err; i++) { | |
219 | int j = i; | |
220 | ||
221 | if (callchain_param.order == ORDER_CALLER) | |
222 | j = ui->idx - i - 1; | |
223 | ||
224 | err = ui->entries[j].ip ? ui->cb(&ui->entries[j], ui->arg) : 0; | |
225 | } | |
226 | ||
5ea84154 JO |
227 | out: |
228 | if (err) | |
229 | pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1)); | |
230 | ||
8bd508b0 JO |
231 | dwfl_end(ui->dwfl); |
232 | free(ui); | |
5ea84154 JO |
233 | return 0; |
234 | } |