projects/linux·blob 9e795d94 · refs

744 lines · 15.6 KiB

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 "trace-event.h"
20#include "evlist.h"
21#include "evsel.h"
22#include "thread_map.h"
23#include "machine.h"
24#include "map.h"
25#include "symbol.h"
26#include "event.h"
27#include "record.h"
28#include "util/mmap.h"
29#include "util/string2.h"
30#include "util/synthetic-events.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
40struct state {
41 u64 done[1024];
42 size_t done_cnt;
43};
44
45static 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 && !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
98static 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
127static 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
179static 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
216static 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
228static 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;
240
241 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
242
243 if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) {
244 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
245 pr_debug("Hypervisor address can not be resolved - skipping\n");
246 return 0;
247 }
248
249 pr_debug("thread__find_map failed\n");
250 return -1;
251 }
252
253 pr_debug("File is: %s\n", al.map->dso->long_name);
254
255 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
256 !dso__is_kcore(al.map->dso)) {
257 pr_debug("Unexpected kernel address - skipping\n");
258 return 0;
259 }
260
261 pr_debug("On file address is: %#"PRIx64"\n", al.addr);
262
263 if (len > BUFSZ)
264 len = BUFSZ;
265
266 /* Do not go off the map */
267 if (addr + len > al.map->end)
268 len = al.map->end - addr;
269
270 /* Read the object code using perf */
271 ret_len = dso__data_read_offset(al.map->dso, thread->maps->machine,
272 al.addr, buf1, len);
273 if (ret_len != len) {
274 pr_debug("dso__data_read_offset failed\n");
275 return -1;
276 }
277
278 /*
279 * Converting addresses for use by objdump requires more information.
280 * map__load() does that. See map__rip_2objdump() for details.
281 */
282 if (map__load(al.map))
283 return -1;
284
285 /* objdump struggles with kcore - try each map only once */
286 if (dso__is_kcore(al.map->dso)) {
287 size_t d;
288
289 for (d = 0; d < state->done_cnt; d++) {
290 if (state->done[d] == al.map->start) {
291 pr_debug("kcore map tested already");
292 pr_debug(" - skipping\n");
293 return 0;
294 }
295 }
296 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
297 pr_debug("Too many kcore maps - skipping\n");
298 return 0;
299 }
300 state->done[state->done_cnt++] = al.map->start;
301 }
302
303 objdump_name = al.map->dso->long_name;
304 if (dso__needs_decompress(al.map->dso)) {
305 if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
306 decomp_name,
307 sizeof(decomp_name)) < 0) {
308 pr_debug("decompression failed\n");
309 return -1;
310 }
311
312 decomp = true;
313 objdump_name = decomp_name;
314 }
315
316 /* Read the object code using objdump */
317 objdump_addr = map__rip_2objdump(al.map, al.addr);
318 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
319
320 if (decomp)
321 unlink(objdump_name);
322
323 if (ret > 0) {
324 /*
325 * The kernel maps are inaccurate - assume objdump is right in
326 * that case.
327 */
328 if (cpumode == PERF_RECORD_MISC_KERNEL ||
329 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
330 len -= ret;
331 if (len) {
332 pr_debug("Reducing len to %zu\n", len);
333 } else if (dso__is_kcore(al.map->dso)) {
334 /*
335 * objdump cannot handle very large segments
336 * that may be found in kcore.
337 */
338 pr_debug("objdump failed for kcore");
339 pr_debug(" - skipping\n");
340 return 0;
341 } else {
342 return -1;
343 }
344 }
345 }
346 if (ret < 0) {
347 pr_debug("read_via_objdump failed\n");
348 return -1;
349 }
350
351 /* The results should be identical */
352 if (memcmp(buf1, buf2, len)) {
353 pr_debug("Bytes read differ from those read by objdump\n");
354 pr_debug("buf1 (dso):\n");
355 dump_buf(buf1, len);
356 pr_debug("buf2 (objdump):\n");
357 dump_buf(buf2, len);
358 return -1;
359 }
360 pr_debug("Bytes read match those read by objdump\n");
361
362 return 0;
363}
364
365static int process_sample_event(struct machine *machine,
366 struct evlist *evlist,
367 union perf_event *event, struct state *state)
368{
369 struct perf_sample sample;
370 struct thread *thread;
371 int ret;
372
373 if (evlist__parse_sample(evlist, event, &sample)) {
374 pr_debug("evlist__parse_sample failed\n");
375 return -1;
376 }
377
378 thread = machine__findnew_thread(machine, sample.pid, sample.tid);
379 if (!thread) {
380 pr_debug("machine__findnew_thread failed\n");
381 return -1;
382 }
383
384 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
385 thread__put(thread);
386 return ret;
387}
388
389static int process_event(struct machine *machine, struct evlist *evlist,
390 union perf_event *event, struct state *state)
391{
392 if (event->header.type == PERF_RECORD_SAMPLE)
393 return process_sample_event(machine, evlist, event, state);
394
395 if (event->header.type == PERF_RECORD_THROTTLE ||
396 event->header.type == PERF_RECORD_UNTHROTTLE)
397 return 0;
398
399 if (event->header.type < PERF_RECORD_MAX) {
400 int ret;
401
402 ret = machine__process_event(machine, event, NULL);
403 if (ret < 0)
404 pr_debug("machine__process_event failed, event type %u\n",
405 event->header.type);
406 return ret;
407 }
408
409 return 0;
410}
411
412static int process_events(struct machine *machine, struct evlist *evlist,
413 struct state *state)
414{
415 union perf_event *event;
416 struct mmap *md;
417 int i, ret;
418
419 for (i = 0; i < evlist->core.nr_mmaps; i++) {
420 md = &evlist->mmap[i];
421 if (perf_mmap__read_init(&md->core) < 0)
422 continue;
423
424 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
425 ret = process_event(machine, evlist, event, state);
426 perf_mmap__consume(&md->core);
427 if (ret < 0)
428 return ret;
429 }
430 perf_mmap__read_done(&md->core);
431 }
432 return 0;
433}
434
435static int comp(const void *a, const void *b)
436{
437 return *(int *)a - *(int *)b;
438}
439
440static void do_sort_something(void)
441{
442 int buf[40960], i;
443
444 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
445 buf[i] = ARRAY_SIZE(buf) - i - 1;
446
447 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
448
449 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
450 if (buf[i] != i) {
451 pr_debug("qsort failed\n");
452 break;
453 }
454 }
455}
456
457static void sort_something(void)
458{
459 int i;
460
461 for (i = 0; i < 10; i++)
462 do_sort_something();
463}
464
465static void syscall_something(void)
466{
467 int pipefd[2];
468 int i;
469
470 for (i = 0; i < 1000; i++) {
471 if (pipe(pipefd) < 0) {
472 pr_debug("pipe failed\n");
473 break;
474 }
475 close(pipefd[1]);
476 close(pipefd[0]);
477 }
478}
479
480static void fs_something(void)
481{
482 const char *test_file_name = "temp-perf-code-reading-test-file--";
483 FILE *f;
484 int i;
485
486 for (i = 0; i < 1000; i++) {
487 f = fopen(test_file_name, "w+");
488 if (f) {
489 fclose(f);
490 unlink(test_file_name);
491 }
492 }
493}
494
495#ifdef __s390x__
496#include "header.h" // for get_cpuid()
497#endif
498
499static const char *do_determine_event(bool excl_kernel)
500{
501 const char *event = excl_kernel ? "cycles:u" : "cycles";
502
503#ifdef __s390x__
504 char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
505 unsigned int family;
506 int ret, cpum_cf_a;
507
508 if (get_cpuid(cpuid, sizeof(cpuid)))
509 goto out_clocks;
510 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
511 model, cpum_cf_v, &cpum_cf_a);
512 if (ret != 5) /* Not available */
513 goto out_clocks;
514 if (excl_kernel && (cpum_cf_a & 4))
515 return event;
516 if (!excl_kernel && (cpum_cf_a & 2))
517 return event;
518
519 /* Fall through: missing authorization */
520out_clocks:
521 event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
522
523#endif
524 return event;
525}
526
527static void do_something(void)
528{
529 fs_something();
530
531 sort_something();
532
533 syscall_something();
534}
535
536enum {
537 TEST_CODE_READING_OK,
538 TEST_CODE_READING_NO_VMLINUX,
539 TEST_CODE_READING_NO_KCORE,
540 TEST_CODE_READING_NO_ACCESS,
541 TEST_CODE_READING_NO_KERNEL_OBJ,
542};
543
544static int do_test_code_reading(bool try_kcore)
545{
546 struct machine *machine;
547 struct thread *thread;
548 struct record_opts opts = {
549 .mmap_pages = UINT_MAX,
550 .user_freq = UINT_MAX,
551 .user_interval = ULLONG_MAX,
552 .freq = 500,
553 .target = {
554 .uses_mmap = true,
555 },
556 };
557 struct state state = {
558 .done_cnt = 0,
559 };
560 struct perf_thread_map *threads = NULL;
561 struct perf_cpu_map *cpus = NULL;
562 struct evlist *evlist = NULL;
563 struct evsel *evsel = NULL;
564 int err = -1, ret;
565 pid_t pid;
566 struct map *map;
567 bool have_vmlinux, have_kcore, excl_kernel = false;
568
569 pid = getpid();
570
571 machine = machine__new_host();
572 machine->env = &perf_env;
573
574 ret = machine__create_kernel_maps(machine);
575 if (ret < 0) {
576 pr_debug("machine__create_kernel_maps failed\n");
577 goto out_err;
578 }
579
580 /* Force the use of kallsyms instead of vmlinux to try kcore */
581 if (try_kcore)
582 symbol_conf.kallsyms_name = "/proc/kallsyms";
583
584 /* Load kernel map */
585 map = machine__kernel_map(machine);
586 ret = map__load(map);
587 if (ret < 0) {
588 pr_debug("map__load failed\n");
589 goto out_err;
590 }
591 have_vmlinux = dso__is_vmlinux(map->dso);
592 have_kcore = dso__is_kcore(map->dso);
593
594 /* 2nd time through we just try kcore */
595 if (try_kcore && !have_kcore)
596 return TEST_CODE_READING_NO_KCORE;
597
598 /* No point getting kernel events if there is no kernel object */
599 if (!have_vmlinux && !have_kcore)
600 excl_kernel = true;
601
602 threads = thread_map__new_by_tid(pid);
603 if (!threads) {
604 pr_debug("thread_map__new_by_tid failed\n");
605 goto out_err;
606 }
607
608 ret = perf_event__synthesize_thread_map(NULL, threads,
609 perf_event__process, machine, false);
610 if (ret < 0) {
611 pr_debug("perf_event__synthesize_thread_map failed\n");
612 goto out_err;
613 }
614
615 thread = machine__findnew_thread(machine, pid, pid);
616 if (!thread) {
617 pr_debug("machine__findnew_thread failed\n");
618 goto out_put;
619 }
620
621 cpus = perf_cpu_map__new(NULL);
622 if (!cpus) {
623 pr_debug("perf_cpu_map__new failed\n");
624 goto out_put;
625 }
626
627 while (1) {
628 const char *str;
629
630 evlist = evlist__new();
631 if (!evlist) {
632 pr_debug("evlist__new failed\n");
633 goto out_put;
634 }
635
636 perf_evlist__set_maps(&evlist->core, cpus, threads);
637
638 str = do_determine_event(excl_kernel);
639 pr_debug("Parsing event '%s'\n", str);
640 ret = parse_events(evlist, str, NULL);
641 if (ret < 0) {
642 pr_debug("parse_events failed\n");
643 goto out_put;
644 }
645
646 evlist__config(evlist, &opts, NULL);
647
648 evsel = evlist__first(evlist);
649
650 evsel->core.attr.comm = 1;
651 evsel->core.attr.disabled = 1;
652 evsel->core.attr.enable_on_exec = 0;
653
654 ret = evlist__open(evlist);
655 if (ret < 0) {
656 if (!excl_kernel) {
657 excl_kernel = true;
658 /*
659 * Both cpus and threads are now owned by evlist
660 * and will be freed by following perf_evlist__set_maps
661 * call. Getting reference to keep them alive.
662 */
663 perf_cpu_map__get(cpus);
664 perf_thread_map__get(threads);
665 perf_evlist__set_maps(&evlist->core, NULL, NULL);
666 evlist__delete(evlist);
667 evlist = NULL;
668 continue;
669 }
670
671 if (verbose > 0) {
672 char errbuf[512];
673 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
674 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
675 }
676
677 goto out_put;
678 }
679 break;
680 }
681
682 ret = evlist__mmap(evlist, UINT_MAX);
683 if (ret < 0) {
684 pr_debug("evlist__mmap failed\n");
685 goto out_put;
686 }
687
688 evlist__enable(evlist);
689
690 do_something();
691
692 evlist__disable(evlist);
693
694 ret = process_events(machine, evlist, &state);
695 if (ret < 0)
696 goto out_put;
697
698 if (!have_vmlinux && !have_kcore && !try_kcore)
699 err = TEST_CODE_READING_NO_KERNEL_OBJ;
700 else if (!have_vmlinux && !try_kcore)
701 err = TEST_CODE_READING_NO_VMLINUX;
702 else if (excl_kernel)
703 err = TEST_CODE_READING_NO_ACCESS;
704 else
705 err = TEST_CODE_READING_OK;
706out_put:
707 thread__put(thread);
708out_err:
709 evlist__delete(evlist);
710 perf_cpu_map__put(cpus);
711 perf_thread_map__put(threads);
712 machine__delete_threads(machine);
713 machine__delete(machine);
714
715 return err;
716}
717
718int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused)
719{
720 int ret;
721
722 ret = do_test_code_reading(false);
723 if (!ret)
724 ret = do_test_code_reading(true);
725
726 switch (ret) {
727 case TEST_CODE_READING_OK:
728 return 0;
729 case TEST_CODE_READING_NO_VMLINUX:
730 pr_debug("no vmlinux\n");
731 return 0;
732 case TEST_CODE_READING_NO_KCORE:
733 pr_debug("no kcore\n");
734 return 0;
735 case TEST_CODE_READING_NO_ACCESS:
736 pr_debug("no access\n");
737 return 0;
738 case TEST_CODE_READING_NO_KERNEL_OBJ:
739 pr_debug("no kernel obj\n");
740 return 0;
741 default:
742 return -1;
743 };
744}