1 // SPDX-License-Identifier: GPL-2.0
2 #include <errno.h>
3 #include <linux/kernel.h>
4 #include <linux/types.h>
5 #include <inttypes.h>
6 #include <stdlib.h>
7 #include <unistd.h>
8 #include <stdio.h>
9 #include <string.h>
10 #include <sys/param.h>
11 #include <perf/cpumap.h>
12 #include <perf/evlist.h>
13 #include <perf/mmap.h>
14
15 #include "debug.h"
16 #include "dso.h"
17 #include "env.h"
18 #include "parse-events.h"
19 #include "evlist.h"
20 #include "evsel.h"
21 #include "thread_map.h"
22 #include "machine.h"
23 #include "map.h"
24 #include "symbol.h"
25 #include "event.h"
26 #include "record.h"
27 #include "util/mmap.h"
28 #include "util/string2.h"
29 #include "util/synthetic-events.h"
30 #include "util/util.h"
31 #include "thread.h"
32
33 #include "tests.h"
34
35 #include <linux/ctype.h>
36
37 #define BUFSZ 1024
38 #define READLEN 128
39
40 struct state {
41 u64 done[1024];
42 size_t done_cnt;
43 };
44
45 static size_t read_objdump_chunk(const char **line, unsigned char **buf,
46 size_t *buf_len)
47 {
48 size_t bytes_read = 0;
49 unsigned char *chunk_start = *buf;
50
51 /* Read bytes */
52 while (*buf_len > 0) {
53 char c1, c2;
54
55 /* Get 2 hex digits */
56 c1 = *(*line)++;
57 if (!isxdigit(c1))
58 break;
59 c2 = *(*line)++;
60 if (!isxdigit(c2))
61 break;
62
63 /* Store byte and advance buf */
64 **buf = (hex(c1) << 4) | hex(c2);
65 (*buf)++;
66 (*buf_len)--;
67 bytes_read++;
68
69 /* End of chunk? */
70 if (isspace(**line))
71 break;
72 }
73
74 /*
75 * objdump will display raw insn as LE if code endian
76 * is LE and bytes_per_chunk > 1. In that case reverse
77 * the chunk we just read.
78 *
79 * see disassemble_bytes() at binutils/objdump.c for details
80 * how objdump chooses display endian)
81 */
82 if (bytes_read > 1 && !host_is_bigendian()) {
83 unsigned char *chunk_end = chunk_start + bytes_read - 1;
84 unsigned char tmp;
85
86 while (chunk_start < chunk_end) {
87 tmp = *chunk_start;
88 *chunk_start = *chunk_end;
89 *chunk_end = tmp;
90 chunk_start++;
91 chunk_end--;
92 }
93 }
94
95 return bytes_read;
96 }
97
98 static size_t read_objdump_line(const char *line, unsigned char *buf,
99 size_t buf_len)
100 {
101 const char *p;
102 size_t ret, bytes_read = 0;
103
104 /* Skip to a colon */
105 p = strchr(line, ':');
106 if (!p)
107 return 0;
108 p++;
109
110 /* Skip initial spaces */
111 while (*p) {
112 if (!isspace(*p))
113 break;
114 p++;
115 }
116
117 do {
118 ret = read_objdump_chunk(&p, &buf, &buf_len);
119 bytes_read += ret;
120 p++;
121 } while (ret > 0);
122
123 /* return number of successfully read bytes */
124 return bytes_read;
125 }
126
127 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
128 {
129 char *line = NULL;
130 size_t line_len, off_last = 0;
131 ssize_t ret;
132 int err = 0;
133 u64 addr, last_addr = start_addr;
134
135 while (off_last < *len) {
136 size_t off, read_bytes, written_bytes;
137 unsigned char tmp[BUFSZ];
138
139 ret = getline(&line, &line_len, f);
140 if (feof(f))
141 break;
142 if (ret < 0) {
143 pr_debug("getline failed\n");
144 err = -1;
145 break;
146 }
147
148 /* read objdump data into temporary buffer */
149 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
150 if (!read_bytes)
151 continue;
152
153 if (sscanf(line, "%"PRIx64, &addr) != 1)
154 continue;
155 if (addr < last_addr) {
156 pr_debug("addr going backwards, read beyond section?\n");
157 break;
158 }
159 last_addr = addr;
160
161 /* copy it from temporary buffer to 'buf' according
162 * to address on current objdump line */
163 off = addr - start_addr;
164 if (off >= *len)
165 break;
166 written_bytes = MIN(read_bytes, *len - off);
167 memcpy(buf + off, tmp, written_bytes);
168 off_last = off + written_bytes;
169 }
170
171 /* len returns number of bytes that could not be read */
172 *len -= off_last;
173
174 free(line);
175
176 return err;
177 }
178
179 static int read_via_objdump(const char *filename, u64 addr, void *buf,
180 size_t len)
181 {
182 char cmd[PATH_MAX * 2];
183 const char *fmt;
184 FILE *f;
185 int ret;
186
187 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
188 ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, addr + len,
189 filename);
190 if (ret <= 0 || (size_t)ret >= sizeof(cmd))
191 return -1;
192
193 pr_debug("Objdump command is: %s\n", cmd);
194
195 /* Ignore objdump errors */
196 strcat(cmd, " 2>/dev/null");
197
198 f = popen(cmd, "r");
199 if (!f) {
200 pr_debug("popen failed\n");
201 return -1;
202 }
203
204 ret = read_objdump_output(f, buf, &len, addr);
205 if (len) {
206 pr_debug("objdump read too few bytes: %zd\n", len);
207 if (!ret)
208 ret = len;
209 }
210
211 pclose(f);
212
213 return ret;
214 }
215
216 static void dump_buf(unsigned char *buf, size_t len)
217 {
218 size_t i;
219
220 for (i = 0; i < len; i++) {
221 pr_debug("0x%02x ", buf[i]);
222 if (i % 16 == 15)
223 pr_debug("\n");
224 }
225 pr_debug("\n");
226 }
227
228 static int read_object_code(u64 addr, size_t len, u8 cpumode,
229 struct thread *thread, struct state *state)
230 {
231 struct addr_location al;
232 unsigned char buf1[BUFSZ] = {0};
233 unsigned char buf2[BUFSZ] = {0};
234 size_t ret_len;
235 u64 objdump_addr;
236 const char *objdump_name;
237 char decomp_name[KMOD_DECOMP_LEN];
238 bool decomp = false;
239 int ret, err = 0;
240 struct dso *dso;
241
242 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
243
244 addr_location__init(&al);
245 if (!thread__find_map(thread, cpumode, addr, &al) || !map__dso(al.map)) {
246 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
247 pr_debug("Hypervisor address can not be resolved - skipping\n");
248 goto out;
249 }
250
251 pr_debug("thread__find_map failed\n");
252 err = -1;
253 goto out;
254 }
255 dso = map__dso(al.map);
256 pr_debug("File is: %s\n", dso__long_name(dso));
257
258 if (dso__symtab_type(dso) == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(dso)) {
259 pr_debug("Unexpected kernel address - skipping\n");
260 goto out;
261 }
262
263 pr_debug("On file address is: %#"PRIx64"\n", al.addr);
264
265 if (len > BUFSZ)
266 len = BUFSZ;
267
268 /* Do not go off the map */
269 if (addr + len > map__end(al.map))
270 len = map__end(al.map) - addr;
271
272 /*
273 * Some architectures (ex: powerpc) have stubs (trampolines) in kernel
274 * modules to manage long jumps. Check if the ip offset falls in stubs
275 * sections for kernel modules. And skip module address after text end
276 */
277 if (dso__is_kmod(dso) && al.addr > dso__text_end(dso)) {
278 pr_debug("skipping the module address %#"PRIx64" after text end\n", al.addr);
279 goto out;
280 }
281
282 /* Read the object code using perf */
283 ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)),
284 al.addr, buf1, len);
285 if (ret_len != len) {
286 pr_debug("dso__data_read_offset failed\n");
287 err = -1;
288 goto out;
289 }
290
291 /*
292 * Converting addresses for use by objdump requires more information.
293 * map__load() does that. See map__rip_2objdump() for details.
294 */
295 if (map__load(al.map)) {
296 err = -1;
297 goto out;
298 }
299
300 /* objdump struggles with kcore - try each map only once */
301 if (dso__is_kcore(dso)) {
302 size_t d;
303
304 for (d = 0; d < state->done_cnt; d++) {
305 if (state->done[d] == map__start(al.map)) {
306 pr_debug("kcore map tested already");
307 pr_debug(" - skipping\n");
308 goto out;
309 }
310 }
311 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
312 pr_debug("Too many kcore maps - skipping\n");
313 goto out;
314 }
315 state->done[state->done_cnt++] = map__start(al.map);
316 }
317
318 objdump_name = dso__long_name(dso);
319 if (dso__needs_decompress(dso)) {
320 if (dso__decompress_kmodule_path(dso, objdump_name,
321 decomp_name,
322 sizeof(decomp_name)) < 0) {
323 pr_debug("decompression failed\n");
324 err = -1;
325 goto out;
326 }
327
328 decomp = true;
329 objdump_name = decomp_name;
330 }
331
332 /* Read the object code using objdump */
333 objdump_addr = map__rip_2objdump(al.map, al.addr);
334 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
335
336 if (decomp)
337 unlink(objdump_name);
338
339 if (ret > 0) {
340 /*
341 * The kernel maps are inaccurate - assume objdump is right in
342 * that case.
343 */
344 if (cpumode == PERF_RECORD_MISC_KERNEL ||
345 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
346 len -= ret;
347 if (len) {
348 pr_debug("Reducing len to %zu\n", len);
349 } else if (dso__is_kcore(dso)) {
350 /*
351 * objdump cannot handle very large segments
352 * that may be found in kcore.
353 */
354 pr_debug("objdump failed for kcore");
355 pr_debug(" - skipping\n");
356 } else {
357 err = -1;
358 }
359 goto out;
360 }
361 }
362 if (ret < 0) {
363 pr_debug("read_via_objdump failed\n");
364 err = -1;
365 goto out;
366 }
367
368 /* The results should be identical */
369 if (memcmp(buf1, buf2, len)) {
370 pr_debug("Bytes read differ from those read by objdump\n");
371 pr_debug("buf1 (dso):\n");
372 dump_buf(buf1, len);
373 pr_debug("buf2 (objdump):\n");
374 dump_buf(buf2, len);
375 err = -1;
376 goto out;
377 }
378 pr_debug("Bytes read match those read by objdump\n");
379 out:
380 addr_location__exit(&al);
381 return err;
382 }
383
384 static int process_sample_event(struct machine *machine,
385 struct evlist *evlist,
386 union perf_event *event, struct state *state)
387 {
388 struct perf_sample sample;
389 struct thread *thread;
390 int ret;
391
392 if (evlist__parse_sample(evlist, event, &sample)) {
393 pr_debug("evlist__parse_sample failed\n");
394 return -1;
395 }
396
397 thread = machine__findnew_thread(machine, sample.pid, sample.tid);
398 if (!thread) {
399 pr_debug("machine__findnew_thread failed\n");
400 return -1;
401 }
402
403 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
404 thread__put(thread);
405 return ret;
406 }
407
408 static int process_event(struct machine *machine, struct evlist *evlist,
409 union perf_event *event, struct state *state)
410 {
411 if (event->header.type == PERF_RECORD_SAMPLE)
412 return process_sample_event(machine, evlist, event, state);
413
414 if (event->header.type == PERF_RECORD_THROTTLE ||
415 event->header.type == PERF_RECORD_UNTHROTTLE)
416 return 0;
417
418 if (event->header.type < PERF_RECORD_MAX) {
419 int ret;
420
421 ret = machine__process_event(machine, event, NULL);
422 if (ret < 0)
423 pr_debug("machine__process_event failed, event type %u\n",
424 event->header.type);
425 return ret;
426 }
427
428 return 0;
429 }
430
431 static int process_events(struct machine *machine, struct evlist *evlist,
432 struct state *state)
433 {
434 union perf_event *event;
435 struct mmap *md;
436 int i, ret;
437
438 for (i = 0; i < evlist->core.nr_mmaps; i++) {
439 md = &evlist->mmap[i];
440 if (perf_mmap__read_init(&md->core) < 0)
441 continue;
442
443 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
444 ret = process_event(machine, evlist, event, state);
445 perf_mmap__consume(&md->core);
446 if (ret < 0)
447 return ret;
448 }
449 perf_mmap__read_done(&md->core);
450 }
451 return 0;
452 }
453
454 static int comp(const void *a, const void *b)
455 {
456 return *(int *)a - *(int *)b;
457 }
458
459 static void do_sort_something(void)
460 {
461 int buf[40960], i;
462
463 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
464 buf[i] = ARRAY_SIZE(buf) - i - 1;
465
466 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
467
468 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
469 if (buf[i] != i) {
470 pr_debug("qsort failed\n");
471 break;
472 }
473 }
474 }
475
476 static void sort_something(void)
477 {
478 int i;
479
480 for (i = 0; i < 10; i++)
481 do_sort_something();
482 }
483
484 static void syscall_something(void)
485 {
486 int pipefd[2];
487 int i;
488
489 for (i = 0; i < 1000; i++) {
490 if (pipe(pipefd) < 0) {
491 pr_debug("pipe failed\n");
492 break;
493 }
494 close(pipefd[1]);
495 close(pipefd[0]);
496 }
497 }
498
499 static void fs_something(void)
500 {
501 const char *test_file_name = "temp-perf-code-reading-test-file--";
502 FILE *f;
503 int i;
504
505 for (i = 0; i < 1000; i++) {
506 f = fopen(test_file_name, "w+");
507 if (f) {
508 fclose(f);
509 unlink(test_file_name);
510 }
511 }
512 }
513
514 static void do_something(void)
515 {
516 fs_something();
517
518 sort_something();
519
520 syscall_something();
521 }
522
523 enum {
524 TEST_CODE_READING_OK,
525 TEST_CODE_READING_NO_VMLINUX,
526 TEST_CODE_READING_NO_KCORE,
527 TEST_CODE_READING_NO_ACCESS,
528 TEST_CODE_READING_NO_KERNEL_OBJ,
529 };
530
531 static int do_test_code_reading(bool try_kcore)
532 {
533 struct machine *machine;
534 struct thread *thread;
535 struct record_opts opts = {
536 .mmap_pages = UINT_MAX,
537 .user_freq = UINT_MAX,
538 .user_interval = ULLONG_MAX,
539 .freq = 500,
540 .target = {
541 .uses_mmap = true,
542 },
543 };
544 struct state state = {
545 .done_cnt = 0,
546 };
547 struct perf_thread_map *threads = NULL;
548 struct perf_cpu_map *cpus = NULL;
549 struct evlist *evlist = NULL;
550 struct evsel *evsel = NULL;
551 int err = -1, ret;
552 pid_t pid;
553 struct map *map;
554 bool have_vmlinux, have_kcore;
555 struct dso *dso;
556 const char *events[] = { "cycles", "cycles:u", "cpu-clock", "cpu-clock:u", NULL };
557 int evidx = 0;
558
559 pid = getpid();
560
561 machine = machine__new_host();
562 machine->env = &perf_env;
563
564 ret = machine__create_kernel_maps(machine);
565 if (ret < 0) {
566 pr_debug("machine__create_kernel_maps failed\n");
567 goto out_err;
568 }
569
570 /* Force the use of kallsyms instead of vmlinux to try kcore */
571 if (try_kcore)
572 symbol_conf.kallsyms_name = "/proc/kallsyms";
573
574 /* Load kernel map */
575 map = machine__kernel_map(machine);
576 ret = map__load(map);
577 if (ret < 0) {
578 pr_debug("map__load failed\n");
579 goto out_err;
580 }
581 dso = map__dso(map);
582 have_vmlinux = dso__is_vmlinux(dso);
583 have_kcore = dso__is_kcore(dso);
584
585 /* 2nd time through we just try kcore */
586 if (try_kcore && !have_kcore)
587 return TEST_CODE_READING_NO_KCORE;
588
589 /* No point getting kernel events if there is no kernel object */
590 if (!have_vmlinux && !have_kcore)
591 evidx++;
592
593 threads = thread_map__new_by_tid(pid);
594 if (!threads) {
595 pr_debug("thread_map__new_by_tid failed\n");
596 goto out_err;
597 }
598
599 ret = perf_event__synthesize_thread_map(NULL, threads,
600 perf_event__process, machine,
601 true, false);
602 if (ret < 0) {
603 pr_debug("perf_event__synthesize_thread_map failed\n");
604 goto out_err;
605 }
606
607 thread = machine__findnew_thread(machine, pid, pid);
608 if (!thread) {
609 pr_debug("machine__findnew_thread failed\n");
610 goto out_put;
611 }
612
613 cpus = perf_cpu_map__new_online_cpus();
614 if (!cpus) {
615 pr_debug("perf_cpu_map__new failed\n");
616 goto out_put;
617 }
618
619 while (events[evidx]) {
620 const char *str;
621
622 evlist = evlist__new();
623 if (!evlist) {
624 pr_debug("evlist__new failed\n");
625 goto out_put;
626 }
627
628 perf_evlist__set_maps(&evlist->core, cpus, threads);
629
630 str = events[evidx];
631 pr_debug("Parsing event '%s'\n", str);
632 ret = parse_event(evlist, str);
633 if (ret < 0) {
634 pr_debug("parse_events failed\n");
635 goto out_put;
636 }
637
638 evlist__config(evlist, &opts, NULL);
639
640 evlist__for_each_entry(evlist, evsel) {
641 evsel->core.attr.comm = 1;
642 evsel->core.attr.disabled = 1;
643 evsel->core.attr.enable_on_exec = 0;
644 }
645
646 ret = evlist__open(evlist);
647 if (ret < 0) {
648 evidx++;
649
650 if (events[evidx] == NULL && verbose > 0) {
651 char errbuf[512];
652 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
653 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
654 }
655
656 /*
657 * Both cpus and threads are now owned by evlist
658 * and will be freed by following perf_evlist__set_maps
659 * call. Getting reference to keep them alive.
660 */
661 perf_cpu_map__get(cpus);
662 perf_thread_map__get(threads);
663 perf_evlist__set_maps(&evlist->core, NULL, NULL);
664 evlist__delete(evlist);
665 evlist = NULL;
666 continue;
667 }
668 break;
669 }
670
671 if (events[evidx] == NULL)
672 goto out_put;
673
674 ret = evlist__mmap(evlist, UINT_MAX);
675 if (ret < 0) {
676 pr_debug("evlist__mmap failed\n");
677 goto out_put;
678 }
679
680 evlist__enable(evlist);
681
682 do_something();
683
684 evlist__disable(evlist);
685
686 ret = process_events(machine, evlist, &state);
687 if (ret < 0)
688 goto out_put;
689
690 if (!have_vmlinux && !have_kcore && !try_kcore)
691 err = TEST_CODE_READING_NO_KERNEL_OBJ;
692 else if (!have_vmlinux && !try_kcore)
693 err = TEST_CODE_READING_NO_VMLINUX;
694 else if (strstr(events[evidx], ":u"))
695 err = TEST_CODE_READING_NO_ACCESS;
696 else
697 err = TEST_CODE_READING_OK;
698 out_put:
699 thread__put(thread);
700 out_err:
701 evlist__delete(evlist);
702 perf_cpu_map__put(cpus);
703 perf_thread_map__put(threads);
704 machine__delete(machine);
705
706 return err;
707 }
708
709 static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
710 {
711 int ret;
712
713 ret = do_test_code_reading(false);
714 if (!ret)
715 ret = do_test_code_reading(true);
716
717 switch (ret) {
718 case TEST_CODE_READING_OK:
719 return 0;
720 case TEST_CODE_READING_NO_VMLINUX:
721 pr_debug("no vmlinux\n");
722 return 0;
723 case TEST_CODE_READING_NO_KCORE:
724 pr_debug("no kcore\n");
725 return 0;
726 case TEST_CODE_READING_NO_ACCESS:
727 pr_debug("no access\n");
728 return 0;
729 case TEST_CODE_READING_NO_KERNEL_OBJ:
730 pr_debug("no kernel obj\n");
731 return 0;
732 default:
733 return -1;
734 };
735 }
736
737 DEFINE_SUITE("Object code reading", code_reading);
738
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