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
read_objdump_chunk(const char ** line,unsigned char ** buf,size_t * buf_len)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
read_objdump_line(const char * line,unsigned char * buf,size_t buf_len)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
read_objdump_output(FILE * f,void * buf,size_t * len,u64 start_addr)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
read_via_objdump(const char * filename,u64 addr,void * buf,size_t len)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, "objdump", 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
dump_buf(unsigned char * buf,size_t len)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
read_object_code(u64 addr,size_t len,u8 cpumode,struct thread * thread,struct state * state)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);
257
258 if (dso->symtab_type == 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 /* Read the object code using perf */
273 ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)),
274 al.addr, buf1, len);
275 if (ret_len != len) {
276 pr_debug("dso__data_read_offset failed\n");
277 err = -1;
278 goto out;
279 }
280
281 /*
282 * Converting addresses for use by objdump requires more information.
283 * map__load() does that. See map__rip_2objdump() for details.
284 */
285 if (map__load(al.map)) {
286 err = -1;
287 goto out;
288 }
289
290 /* objdump struggles with kcore - try each map only once */
291 if (dso__is_kcore(dso)) {
292 size_t d;
293
294 for (d = 0; d < state->done_cnt; d++) {
295 if (state->done[d] == map__start(al.map)) {
296 pr_debug("kcore map tested already");
297 pr_debug(" - skipping\n");
298 goto out;
299 }
300 }
301 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
302 pr_debug("Too many kcore maps - skipping\n");
303 goto out;
304 }
305 state->done[state->done_cnt++] = map__start(al.map);
306 }
307
308 objdump_name = dso->long_name;
309 if (dso__needs_decompress(dso)) {
310 if (dso__decompress_kmodule_path(dso, objdump_name,
311 decomp_name,
312 sizeof(decomp_name)) < 0) {
313 pr_debug("decompression failed\n");
314 err = -1;
315 goto out;
316 }
317
318 decomp = true;
319 objdump_name = decomp_name;
320 }
321
322 /* Read the object code using objdump */
323 objdump_addr = map__rip_2objdump(al.map, al.addr);
324 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
325
326 if (decomp)
327 unlink(objdump_name);
328
329 if (ret > 0) {
330 /*
331 * The kernel maps are inaccurate - assume objdump is right in
332 * that case.
333 */
334 if (cpumode == PERF_RECORD_MISC_KERNEL ||
335 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
336 len -= ret;
337 if (len) {
338 pr_debug("Reducing len to %zu\n", len);
339 } else if (dso__is_kcore(dso)) {
340 /*
341 * objdump cannot handle very large segments
342 * that may be found in kcore.
343 */
344 pr_debug("objdump failed for kcore");
345 pr_debug(" - skipping\n");
346 } else {
347 err = -1;
348 }
349 goto out;
350 }
351 }
352 if (ret < 0) {
353 pr_debug("read_via_objdump failed\n");
354 err = -1;
355 goto out;
356 }
357
358 /* The results should be identical */
359 if (memcmp(buf1, buf2, len)) {
360 pr_debug("Bytes read differ from those read by objdump\n");
361 pr_debug("buf1 (dso):\n");
362 dump_buf(buf1, len);
363 pr_debug("buf2 (objdump):\n");
364 dump_buf(buf2, len);
365 err = -1;
366 goto out;
367 }
368 pr_debug("Bytes read match those read by objdump\n");
369 out:
370 addr_location__exit(&al);
371 return err;
372 }
373
process_sample_event(struct machine * machine,struct evlist * evlist,union perf_event * event,struct state * state)374 static int process_sample_event(struct machine *machine,
375 struct evlist *evlist,
376 union perf_event *event, struct state *state)
377 {
378 struct perf_sample sample;
379 struct thread *thread;
380 int ret;
381
382 if (evlist__parse_sample(evlist, event, &sample)) {
383 pr_debug("evlist__parse_sample failed\n");
384 return -1;
385 }
386
387 thread = machine__findnew_thread(machine, sample.pid, sample.tid);
388 if (!thread) {
389 pr_debug("machine__findnew_thread failed\n");
390 return -1;
391 }
392
393 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
394 thread__put(thread);
395 return ret;
396 }
397
process_event(struct machine * machine,struct evlist * evlist,union perf_event * event,struct state * state)398 static int process_event(struct machine *machine, struct evlist *evlist,
399 union perf_event *event, struct state *state)
400 {
401 if (event->header.type == PERF_RECORD_SAMPLE)
402 return process_sample_event(machine, evlist, event, state);
403
404 if (event->header.type == PERF_RECORD_THROTTLE ||
405 event->header.type == PERF_RECORD_UNTHROTTLE)
406 return 0;
407
408 if (event->header.type < PERF_RECORD_MAX) {
409 int ret;
410
411 ret = machine__process_event(machine, event, NULL);
412 if (ret < 0)
413 pr_debug("machine__process_event failed, event type %u\n",
414 event->header.type);
415 return ret;
416 }
417
418 return 0;
419 }
420
process_events(struct machine * machine,struct evlist * evlist,struct state * state)421 static int process_events(struct machine *machine, struct evlist *evlist,
422 struct state *state)
423 {
424 union perf_event *event;
425 struct mmap *md;
426 int i, ret;
427
428 for (i = 0; i < evlist->core.nr_mmaps; i++) {
429 md = &evlist->mmap[i];
430 if (perf_mmap__read_init(&md->core) < 0)
431 continue;
432
433 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
434 ret = process_event(machine, evlist, event, state);
435 perf_mmap__consume(&md->core);
436 if (ret < 0)
437 return ret;
438 }
439 perf_mmap__read_done(&md->core);
440 }
441 return 0;
442 }
443
comp(const void * a,const void * b)444 static int comp(const void *a, const void *b)
445 {
446 return *(int *)a - *(int *)b;
447 }
448
do_sort_something(void)449 static void do_sort_something(void)
450 {
451 int buf[40960], i;
452
453 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
454 buf[i] = ARRAY_SIZE(buf) - i - 1;
455
456 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
457
458 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
459 if (buf[i] != i) {
460 pr_debug("qsort failed\n");
461 break;
462 }
463 }
464 }
465
sort_something(void)466 static void sort_something(void)
467 {
468 int i;
469
470 for (i = 0; i < 10; i++)
471 do_sort_something();
472 }
473
syscall_something(void)474 static void syscall_something(void)
475 {
476 int pipefd[2];
477 int i;
478
479 for (i = 0; i < 1000; i++) {
480 if (pipe(pipefd) < 0) {
481 pr_debug("pipe failed\n");
482 break;
483 }
484 close(pipefd[1]);
485 close(pipefd[0]);
486 }
487 }
488
fs_something(void)489 static void fs_something(void)
490 {
491 const char *test_file_name = "temp-perf-code-reading-test-file--";
492 FILE *f;
493 int i;
494
495 for (i = 0; i < 1000; i++) {
496 f = fopen(test_file_name, "w+");
497 if (f) {
498 fclose(f);
499 unlink(test_file_name);
500 }
501 }
502 }
503
504 #ifdef __s390x__
505 #include "header.h" // for get_cpuid()
506 #endif
507
do_determine_event(bool excl_kernel)508 static const char *do_determine_event(bool excl_kernel)
509 {
510 const char *event = excl_kernel ? "cycles:u" : "cycles";
511
512 #ifdef __s390x__
513 char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
514 unsigned int family;
515 int ret, cpum_cf_a;
516
517 if (get_cpuid(cpuid, sizeof(cpuid)))
518 goto out_clocks;
519 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
520 model, cpum_cf_v, &cpum_cf_a);
521 if (ret != 5) /* Not available */
522 goto out_clocks;
523 if (excl_kernel && (cpum_cf_a & 4))
524 return event;
525 if (!excl_kernel && (cpum_cf_a & 2))
526 return event;
527
528 /* Fall through: missing authorization */
529 out_clocks:
530 event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
531
532 #endif
533 return event;
534 }
535
do_something(void)536 static void do_something(void)
537 {
538 fs_something();
539
540 sort_something();
541
542 syscall_something();
543 }
544
545 enum {
546 TEST_CODE_READING_OK,
547 TEST_CODE_READING_NO_VMLINUX,
548 TEST_CODE_READING_NO_KCORE,
549 TEST_CODE_READING_NO_ACCESS,
550 TEST_CODE_READING_NO_KERNEL_OBJ,
551 };
552
do_test_code_reading(bool try_kcore)553 static int do_test_code_reading(bool try_kcore)
554 {
555 struct machine *machine;
556 struct thread *thread;
557 struct record_opts opts = {
558 .mmap_pages = UINT_MAX,
559 .user_freq = UINT_MAX,
560 .user_interval = ULLONG_MAX,
561 .freq = 500,
562 .target = {
563 .uses_mmap = true,
564 },
565 };
566 struct state state = {
567 .done_cnt = 0,
568 };
569 struct perf_thread_map *threads = NULL;
570 struct perf_cpu_map *cpus = NULL;
571 struct evlist *evlist = NULL;
572 struct evsel *evsel = NULL;
573 int err = -1, ret;
574 pid_t pid;
575 struct map *map;
576 bool have_vmlinux, have_kcore, excl_kernel = false;
577 struct dso *dso;
578
579 pid = getpid();
580
581 machine = machine__new_host();
582 machine->env = &perf_env;
583
584 ret = machine__create_kernel_maps(machine);
585 if (ret < 0) {
586 pr_debug("machine__create_kernel_maps failed\n");
587 goto out_err;
588 }
589
590 /* Force the use of kallsyms instead of vmlinux to try kcore */
591 if (try_kcore)
592 symbol_conf.kallsyms_name = "/proc/kallsyms";
593
594 /* Load kernel map */
595 map = machine__kernel_map(machine);
596 ret = map__load(map);
597 if (ret < 0) {
598 pr_debug("map__load failed\n");
599 goto out_err;
600 }
601 dso = map__dso(map);
602 have_vmlinux = dso__is_vmlinux(dso);
603 have_kcore = dso__is_kcore(dso);
604
605 /* 2nd time through we just try kcore */
606 if (try_kcore && !have_kcore)
607 return TEST_CODE_READING_NO_KCORE;
608
609 /* No point getting kernel events if there is no kernel object */
610 if (!have_vmlinux && !have_kcore)
611 excl_kernel = true;
612
613 threads = thread_map__new_by_tid(pid);
614 if (!threads) {
615 pr_debug("thread_map__new_by_tid failed\n");
616 goto out_err;
617 }
618
619 ret = perf_event__synthesize_thread_map(NULL, threads,
620 perf_event__process, machine,
621 true, false);
622 if (ret < 0) {
623 pr_debug("perf_event__synthesize_thread_map failed\n");
624 goto out_err;
625 }
626
627 thread = machine__findnew_thread(machine, pid, pid);
628 if (!thread) {
629 pr_debug("machine__findnew_thread failed\n");
630 goto out_put;
631 }
632
633 cpus = perf_cpu_map__new(NULL);
634 if (!cpus) {
635 pr_debug("perf_cpu_map__new failed\n");
636 goto out_put;
637 }
638
639 while (1) {
640 const char *str;
641
642 evlist = evlist__new();
643 if (!evlist) {
644 pr_debug("evlist__new failed\n");
645 goto out_put;
646 }
647
648 perf_evlist__set_maps(&evlist->core, cpus, threads);
649
650 str = do_determine_event(excl_kernel);
651 pr_debug("Parsing event '%s'\n", str);
652 ret = parse_event(evlist, str);
653 if (ret < 0) {
654 pr_debug("parse_events failed\n");
655 goto out_put;
656 }
657
658 evlist__config(evlist, &opts, NULL);
659
660 evlist__for_each_entry(evlist, evsel) {
661 evsel->core.attr.comm = 1;
662 evsel->core.attr.disabled = 1;
663 evsel->core.attr.enable_on_exec = 0;
664 }
665
666 ret = evlist__open(evlist);
667 if (ret < 0) {
668 if (!excl_kernel) {
669 excl_kernel = true;
670 /*
671 * Both cpus and threads are now owned by evlist
672 * and will be freed by following perf_evlist__set_maps
673 * call. Getting reference to keep them alive.
674 */
675 perf_cpu_map__get(cpus);
676 perf_thread_map__get(threads);
677 perf_evlist__set_maps(&evlist->core, NULL, NULL);
678 evlist__delete(evlist);
679 evlist = NULL;
680 continue;
681 }
682
683 if (verbose > 0) {
684 char errbuf[512];
685 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
686 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
687 }
688
689 goto out_put;
690 }
691 break;
692 }
693
694 ret = evlist__mmap(evlist, UINT_MAX);
695 if (ret < 0) {
696 pr_debug("evlist__mmap failed\n");
697 goto out_put;
698 }
699
700 evlist__enable(evlist);
701
702 do_something();
703
704 evlist__disable(evlist);
705
706 ret = process_events(machine, evlist, &state);
707 if (ret < 0)
708 goto out_put;
709
710 if (!have_vmlinux && !have_kcore && !try_kcore)
711 err = TEST_CODE_READING_NO_KERNEL_OBJ;
712 else if (!have_vmlinux && !try_kcore)
713 err = TEST_CODE_READING_NO_VMLINUX;
714 else if (excl_kernel)
715 err = TEST_CODE_READING_NO_ACCESS;
716 else
717 err = TEST_CODE_READING_OK;
718 out_put:
719 thread__put(thread);
720 out_err:
721 evlist__delete(evlist);
722 perf_cpu_map__put(cpus);
723 perf_thread_map__put(threads);
724 machine__delete(machine);
725
726 return err;
727 }
728
test__code_reading(struct test_suite * test __maybe_unused,int subtest __maybe_unused)729 static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
730 {
731 int ret;
732
733 ret = do_test_code_reading(false);
734 if (!ret)
735 ret = do_test_code_reading(true);
736
737 switch (ret) {
738 case TEST_CODE_READING_OK:
739 return 0;
740 case TEST_CODE_READING_NO_VMLINUX:
741 pr_debug("no vmlinux\n");
742 return 0;
743 case TEST_CODE_READING_NO_KCORE:
744 pr_debug("no kcore\n");
745 return 0;
746 case TEST_CODE_READING_NO_ACCESS:
747 pr_debug("no access\n");
748 return 0;
749 case TEST_CODE_READING_NO_KERNEL_OBJ:
750 pr_debug("no kernel obj\n");
751 return 0;
752 default:
753 return -1;
754 };
755 }
756
757 DEFINE_SUITE("Object code reading", code_reading);
758