1 #include <sys/types.h>
2 #include <stdlib.h>
3 #include <unistd.h>
4 #include <stdio.h>
5 #include <inttypes.h>
6 #include <ctype.h>
7 #include <string.h>
8
9 #include "parse-events.h"
10 #include "evlist.h"
11 #include "evsel.h"
12 #include "thread_map.h"
13 #include "cpumap.h"
14 #include "machine.h"
15 #include "event.h"
16 #include "thread.h"
17
18 #include "tests.h"
19
20 #define BUFSZ 1024
21 #define READLEN 128
22
23 struct state {
24 u64 done[1024];
25 size_t done_cnt;
26 };
27
hex(char c)28 static unsigned int hex(char c)
29 {
30 if (c >= '0' && c <= '9')
31 return c - '0';
32 if (c >= 'a' && c <= 'f')
33 return c - 'a' + 10;
34 return c - 'A' + 10;
35 }
36
read_objdump_line(const char * line,size_t line_len,void ** buf,size_t * len)37 static void read_objdump_line(const char *line, size_t line_len, void **buf,
38 size_t *len)
39 {
40 const char *p;
41 size_t i;
42
43 /* Skip to a colon */
44 p = strchr(line, ':');
45 if (!p)
46 return;
47 i = p + 1 - line;
48
49 /* Read bytes */
50 while (*len) {
51 char c1, c2;
52
53 /* Skip spaces */
54 for (; i < line_len; i++) {
55 if (!isspace(line[i]))
56 break;
57 }
58 /* Get 2 hex digits */
59 if (i >= line_len || !isxdigit(line[i]))
60 break;
61 c1 = line[i++];
62 if (i >= line_len || !isxdigit(line[i]))
63 break;
64 c2 = line[i++];
65 /* Followed by a space */
66 if (i < line_len && line[i] && !isspace(line[i]))
67 break;
68 /* Store byte */
69 *(unsigned char *)*buf = (hex(c1) << 4) | hex(c2);
70 *buf += 1;
71 *len -= 1;
72 }
73 }
74
read_objdump_output(FILE * f,void ** buf,size_t * len)75 static int read_objdump_output(FILE *f, void **buf, size_t *len)
76 {
77 char *line = NULL;
78 size_t line_len;
79 ssize_t ret;
80 int err = 0;
81
82 while (1) {
83 ret = getline(&line, &line_len, f);
84 if (feof(f))
85 break;
86 if (ret < 0) {
87 pr_debug("getline failed\n");
88 err = -1;
89 break;
90 }
91 read_objdump_line(line, ret, buf, len);
92 }
93
94 free(line);
95
96 return err;
97 }
98
read_via_objdump(const char * filename,u64 addr,void * buf,size_t len)99 static int read_via_objdump(const char *filename, u64 addr, void *buf,
100 size_t len)
101 {
102 char cmd[PATH_MAX * 2];
103 const char *fmt;
104 FILE *f;
105 int ret;
106
107 fmt = "%s -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
108 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
109 filename);
110 if (ret <= 0 || (size_t)ret >= sizeof(cmd))
111 return -1;
112
113 pr_debug("Objdump command is: %s\n", cmd);
114
115 /* Ignore objdump errors */
116 strcat(cmd, " 2>/dev/null");
117
118 f = popen(cmd, "r");
119 if (!f) {
120 pr_debug("popen failed\n");
121 return -1;
122 }
123
124 ret = read_objdump_output(f, &buf, &len);
125 if (len) {
126 pr_debug("objdump read too few bytes\n");
127 if (!ret)
128 ret = len;
129 }
130
131 pclose(f);
132
133 return ret;
134 }
135
read_object_code(u64 addr,size_t len,u8 cpumode,struct thread * thread,struct machine * machine,struct state * state)136 static int read_object_code(u64 addr, size_t len, u8 cpumode,
137 struct thread *thread, struct machine *machine,
138 struct state *state)
139 {
140 struct addr_location al;
141 unsigned char buf1[BUFSZ];
142 unsigned char buf2[BUFSZ];
143 size_t ret_len;
144 u64 objdump_addr;
145 int ret;
146
147 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
148
149 thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION, addr,
150 &al);
151 if (!al.map || !al.map->dso) {
152 pr_debug("thread__find_addr_map failed\n");
153 return -1;
154 }
155
156 pr_debug("File is: %s\n", al.map->dso->long_name);
157
158 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
159 !dso__is_kcore(al.map->dso)) {
160 pr_debug("Unexpected kernel address - skipping\n");
161 return 0;
162 }
163
164 pr_debug("On file address is: %#"PRIx64"\n", al.addr);
165
166 if (len > BUFSZ)
167 len = BUFSZ;
168
169 /* Do not go off the map */
170 if (addr + len > al.map->end)
171 len = al.map->end - addr;
172
173 /* Read the object code using perf */
174 ret_len = dso__data_read_offset(al.map->dso, machine, al.addr, buf1,
175 len);
176 if (ret_len != len) {
177 pr_debug("dso__data_read_offset failed\n");
178 return -1;
179 }
180
181 /*
182 * Converting addresses for use by objdump requires more information.
183 * map__load() does that. See map__rip_2objdump() for details.
184 */
185 if (map__load(al.map, NULL))
186 return -1;
187
188 /* objdump struggles with kcore - try each map only once */
189 if (dso__is_kcore(al.map->dso)) {
190 size_t d;
191
192 for (d = 0; d < state->done_cnt; d++) {
193 if (state->done[d] == al.map->start) {
194 pr_debug("kcore map tested already");
195 pr_debug(" - skipping\n");
196 return 0;
197 }
198 }
199 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
200 pr_debug("Too many kcore maps - skipping\n");
201 return 0;
202 }
203 state->done[state->done_cnt++] = al.map->start;
204 }
205
206 /* Read the object code using objdump */
207 objdump_addr = map__rip_2objdump(al.map, al.addr);
208 ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
209 if (ret > 0) {
210 /*
211 * The kernel maps are inaccurate - assume objdump is right in
212 * that case.
213 */
214 if (cpumode == PERF_RECORD_MISC_KERNEL ||
215 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
216 len -= ret;
217 if (len) {
218 pr_debug("Reducing len to %zu\n", len);
219 } else if (dso__is_kcore(al.map->dso)) {
220 /*
221 * objdump cannot handle very large segments
222 * that may be found in kcore.
223 */
224 pr_debug("objdump failed for kcore");
225 pr_debug(" - skipping\n");
226 return 0;
227 } else {
228 return -1;
229 }
230 }
231 }
232 if (ret < 0) {
233 pr_debug("read_via_objdump failed\n");
234 return -1;
235 }
236
237 /* The results should be identical */
238 if (memcmp(buf1, buf2, len)) {
239 pr_debug("Bytes read differ from those read by objdump\n");
240 return -1;
241 }
242 pr_debug("Bytes read match those read by objdump\n");
243
244 return 0;
245 }
246
process_sample_event(struct machine * machine,struct perf_evlist * evlist,union perf_event * event,struct state * state)247 static int process_sample_event(struct machine *machine,
248 struct perf_evlist *evlist,
249 union perf_event *event, struct state *state)
250 {
251 struct perf_sample sample;
252 struct thread *thread;
253 u8 cpumode;
254
255 if (perf_evlist__parse_sample(evlist, event, &sample)) {
256 pr_debug("perf_evlist__parse_sample failed\n");
257 return -1;
258 }
259
260 thread = machine__findnew_thread(machine, sample.pid, sample.pid);
261 if (!thread) {
262 pr_debug("machine__findnew_thread failed\n");
263 return -1;
264 }
265
266 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
267
268 return read_object_code(sample.ip, READLEN, cpumode, thread, machine,
269 state);
270 }
271
process_event(struct machine * machine,struct perf_evlist * evlist,union perf_event * event,struct state * state)272 static int process_event(struct machine *machine, struct perf_evlist *evlist,
273 union perf_event *event, struct state *state)
274 {
275 if (event->header.type == PERF_RECORD_SAMPLE)
276 return process_sample_event(machine, evlist, event, state);
277
278 if (event->header.type < PERF_RECORD_MAX)
279 return machine__process_event(machine, event);
280
281 return 0;
282 }
283
process_events(struct machine * machine,struct perf_evlist * evlist,struct state * state)284 static int process_events(struct machine *machine, struct perf_evlist *evlist,
285 struct state *state)
286 {
287 union perf_event *event;
288 int i, ret;
289
290 for (i = 0; i < evlist->nr_mmaps; i++) {
291 while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
292 ret = process_event(machine, evlist, event, state);
293 perf_evlist__mmap_consume(evlist, i);
294 if (ret < 0)
295 return ret;
296 }
297 }
298 return 0;
299 }
300
comp(const void * a,const void * b)301 static int comp(const void *a, const void *b)
302 {
303 return *(int *)a - *(int *)b;
304 }
305
do_sort_something(void)306 static void do_sort_something(void)
307 {
308 int buf[40960], i;
309
310 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
311 buf[i] = ARRAY_SIZE(buf) - i - 1;
312
313 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
314
315 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
316 if (buf[i] != i) {
317 pr_debug("qsort failed\n");
318 break;
319 }
320 }
321 }
322
sort_something(void)323 static void sort_something(void)
324 {
325 int i;
326
327 for (i = 0; i < 10; i++)
328 do_sort_something();
329 }
330
syscall_something(void)331 static void syscall_something(void)
332 {
333 int pipefd[2];
334 int i;
335
336 for (i = 0; i < 1000; i++) {
337 if (pipe(pipefd) < 0) {
338 pr_debug("pipe failed\n");
339 break;
340 }
341 close(pipefd[1]);
342 close(pipefd[0]);
343 }
344 }
345
fs_something(void)346 static void fs_something(void)
347 {
348 const char *test_file_name = "temp-perf-code-reading-test-file--";
349 FILE *f;
350 int i;
351
352 for (i = 0; i < 1000; i++) {
353 f = fopen(test_file_name, "w+");
354 if (f) {
355 fclose(f);
356 unlink(test_file_name);
357 }
358 }
359 }
360
do_something(void)361 static void do_something(void)
362 {
363 fs_something();
364
365 sort_something();
366
367 syscall_something();
368 }
369
370 enum {
371 TEST_CODE_READING_OK,
372 TEST_CODE_READING_NO_VMLINUX,
373 TEST_CODE_READING_NO_KCORE,
374 TEST_CODE_READING_NO_ACCESS,
375 TEST_CODE_READING_NO_KERNEL_OBJ,
376 };
377
do_test_code_reading(bool try_kcore)378 static int do_test_code_reading(bool try_kcore)
379 {
380 struct machines machines;
381 struct machine *machine;
382 struct thread *thread;
383 struct perf_record_opts opts = {
384 .mmap_pages = UINT_MAX,
385 .user_freq = UINT_MAX,
386 .user_interval = ULLONG_MAX,
387 .freq = 4000,
388 .target = {
389 .uses_mmap = true,
390 },
391 };
392 struct state state = {
393 .done_cnt = 0,
394 };
395 struct thread_map *threads = NULL;
396 struct cpu_map *cpus = NULL;
397 struct perf_evlist *evlist = NULL;
398 struct perf_evsel *evsel = NULL;
399 int err = -1, ret;
400 pid_t pid;
401 struct map *map;
402 bool have_vmlinux, have_kcore, excl_kernel = false;
403
404 pid = getpid();
405
406 machines__init(&machines);
407 machine = &machines.host;
408
409 ret = machine__create_kernel_maps(machine);
410 if (ret < 0) {
411 pr_debug("machine__create_kernel_maps failed\n");
412 goto out_err;
413 }
414
415 /* Force the use of kallsyms instead of vmlinux to try kcore */
416 if (try_kcore)
417 symbol_conf.kallsyms_name = "/proc/kallsyms";
418
419 /* Load kernel map */
420 map = machine->vmlinux_maps[MAP__FUNCTION];
421 ret = map__load(map, NULL);
422 if (ret < 0) {
423 pr_debug("map__load failed\n");
424 goto out_err;
425 }
426 have_vmlinux = dso__is_vmlinux(map->dso);
427 have_kcore = dso__is_kcore(map->dso);
428
429 /* 2nd time through we just try kcore */
430 if (try_kcore && !have_kcore)
431 return TEST_CODE_READING_NO_KCORE;
432
433 /* No point getting kernel events if there is no kernel object */
434 if (!have_vmlinux && !have_kcore)
435 excl_kernel = true;
436
437 threads = thread_map__new_by_tid(pid);
438 if (!threads) {
439 pr_debug("thread_map__new_by_tid failed\n");
440 goto out_err;
441 }
442
443 ret = perf_event__synthesize_thread_map(NULL, threads,
444 perf_event__process, machine);
445 if (ret < 0) {
446 pr_debug("perf_event__synthesize_thread_map failed\n");
447 goto out_err;
448 }
449
450 thread = machine__findnew_thread(machine, pid, pid);
451 if (!thread) {
452 pr_debug("machine__findnew_thread failed\n");
453 goto out_err;
454 }
455
456 cpus = cpu_map__new(NULL);
457 if (!cpus) {
458 pr_debug("cpu_map__new failed\n");
459 goto out_err;
460 }
461
462 while (1) {
463 const char *str;
464
465 evlist = perf_evlist__new();
466 if (!evlist) {
467 pr_debug("perf_evlist__new failed\n");
468 goto out_err;
469 }
470
471 perf_evlist__set_maps(evlist, cpus, threads);
472
473 if (excl_kernel)
474 str = "cycles:u";
475 else
476 str = "cycles";
477 pr_debug("Parsing event '%s'\n", str);
478 ret = parse_events(evlist, str);
479 if (ret < 0) {
480 pr_debug("parse_events failed\n");
481 goto out_err;
482 }
483
484 perf_evlist__config(evlist, &opts);
485
486 evsel = perf_evlist__first(evlist);
487
488 evsel->attr.comm = 1;
489 evsel->attr.disabled = 1;
490 evsel->attr.enable_on_exec = 0;
491
492 ret = perf_evlist__open(evlist);
493 if (ret < 0) {
494 if (!excl_kernel) {
495 excl_kernel = true;
496 perf_evlist__delete(evlist);
497 evlist = NULL;
498 continue;
499 }
500 pr_debug("perf_evlist__open failed\n");
501 goto out_err;
502 }
503 break;
504 }
505
506 ret = perf_evlist__mmap(evlist, UINT_MAX, false);
507 if (ret < 0) {
508 pr_debug("perf_evlist__mmap failed\n");
509 goto out_err;
510 }
511
512 perf_evlist__enable(evlist);
513
514 do_something();
515
516 perf_evlist__disable(evlist);
517
518 ret = process_events(machine, evlist, &state);
519 if (ret < 0)
520 goto out_err;
521
522 if (!have_vmlinux && !have_kcore && !try_kcore)
523 err = TEST_CODE_READING_NO_KERNEL_OBJ;
524 else if (!have_vmlinux && !try_kcore)
525 err = TEST_CODE_READING_NO_VMLINUX;
526 else if (excl_kernel)
527 err = TEST_CODE_READING_NO_ACCESS;
528 else
529 err = TEST_CODE_READING_OK;
530 out_err:
531 if (evlist) {
532 perf_evlist__munmap(evlist);
533 perf_evlist__close(evlist);
534 perf_evlist__delete(evlist);
535 }
536 if (cpus)
537 cpu_map__delete(cpus);
538 if (threads)
539 thread_map__delete(threads);
540 machines__destroy_kernel_maps(&machines);
541 machine__delete_threads(machine);
542 machines__exit(&machines);
543
544 return err;
545 }
546
test__code_reading(void)547 int test__code_reading(void)
548 {
549 int ret;
550
551 ret = do_test_code_reading(false);
552 if (!ret)
553 ret = do_test_code_reading(true);
554
555 switch (ret) {
556 case TEST_CODE_READING_OK:
557 return 0;
558 case TEST_CODE_READING_NO_VMLINUX:
559 fprintf(stderr, " (no vmlinux)");
560 return 0;
561 case TEST_CODE_READING_NO_KCORE:
562 fprintf(stderr, " (no kcore)");
563 return 0;
564 case TEST_CODE_READING_NO_ACCESS:
565 fprintf(stderr, " (no access)");
566 return 0;
567 case TEST_CODE_READING_NO_KERNEL_OBJ:
568 fprintf(stderr, " (no kernel obj)");
569 return 0;
570 default:
571 return -1;
572 };
573 }
574