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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
12#include "parse-events.h"
13#include "evlist.h"
14#include "evsel.h"
15#include "thread_map.h"
16#include "cpumap.h"
17#include "machine.h"
18#include "event.h"
19#include "thread.h"
20
21#include "tests.h"
22
23#include "sane_ctype.h"
24
25#define BUFSZ 1024
26#define READLEN 128
27
28struct state {
29 u64 done[1024];
30 size_t done_cnt;
31};
32
33static unsigned int hex(char c)
34{
35 if (c >= '0' && c <= '9')
36 return c - '0';
37 if (c >= 'a' && c <= 'f')
38 return c - 'a' + 10;
39 return c - 'A' + 10;
40}
41
42static size_t read_objdump_chunk(const char **line, unsigned char **buf,
43 size_t *buf_len)
44{
45 size_t bytes_read = 0;
46 unsigned char *chunk_start = *buf;
47
48 /* Read bytes */
49 while (*buf_len > 0) {
50 char c1, c2;
51
52 /* Get 2 hex digits */
53 c1 = *(*line)++;
54 if (!isxdigit(c1))
55 break;
56 c2 = *(*line)++;
57 if (!isxdigit(c2))
58 break;
59
60 /* Store byte and advance buf */
61 **buf = (hex(c1) << 4) | hex(c2);
62 (*buf)++;
63 (*buf_len)--;
64 bytes_read++;
65
66 /* End of chunk? */
67 if (isspace(**line))
68 break;
69 }
70
71 /*
72 * objdump will display raw insn as LE if code endian
73 * is LE and bytes_per_chunk > 1. In that case reverse
74 * the chunk we just read.
75 *
76 * see disassemble_bytes() at binutils/objdump.c for details
77 * how objdump chooses display endian)
78 */
79 if (bytes_read > 1 && !bigendian()) {
80 unsigned char *chunk_end = chunk_start + bytes_read - 1;
81 unsigned char tmp;
82
83 while (chunk_start < chunk_end) {
84 tmp = *chunk_start;
85 *chunk_start = *chunk_end;
86 *chunk_end = tmp;
87 chunk_start++;
88 chunk_end--;
89 }
90 }
91
92 return bytes_read;
93}
94
95static size_t read_objdump_line(const char *line, unsigned char *buf,
96 size_t buf_len)
97{
98 const char *p;
99 size_t ret, bytes_read = 0;
100
101 /* Skip to a colon */
102 p = strchr(line, ':');
103 if (!p)
104 return 0;
105 p++;
106
107 /* Skip initial spaces */
108 while (*p) {
109 if (!isspace(*p))
110 break;
111 p++;
112 }
113
114 do {
115 ret = read_objdump_chunk(&p, &buf, &buf_len);
116 bytes_read += ret;
117 p++;
118 } while (ret > 0);
119
120 /* return number of successfully read bytes */
121 return bytes_read;
122}
123
124static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
125{
126 char *line = NULL;
127 size_t line_len, off_last = 0;
128 ssize_t ret;
129 int err = 0;
130 u64 addr, last_addr = start_addr;
131
132 while (off_last < *len) {
133 size_t off, read_bytes, written_bytes;
134 unsigned char tmp[BUFSZ];
135
136 ret = getline(&line, &line_len, f);
137 if (feof(f))
138 break;
139 if (ret < 0) {
140 pr_debug("getline failed\n");
141 err = -1;
142 break;
143 }
144
145 /* read objdump data into temporary buffer */
146 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
147 if (!read_bytes)
148 continue;
149
150 if (sscanf(line, "%"PRIx64, &addr) != 1)
151 continue;
152 if (addr < last_addr) {
153 pr_debug("addr going backwards, read beyond section?\n");
154 break;
155 }
156 last_addr = addr;
157
158 /* copy it from temporary buffer to 'buf' according
159 * to address on current objdump line */
160 off = addr - start_addr;
161 if (off >= *len)
162 break;
163 written_bytes = MIN(read_bytes, *len - off);
164 memcpy(buf + off, tmp, written_bytes);
165 off_last = off + written_bytes;
166 }
167
168 /* len returns number of bytes that could not be read */
169 *len -= off_last;
170
171 free(line);
172
173 return err;
174}
175
176static int read_via_objdump(const char *filename, u64 addr, void *buf,
177 size_t len)
178{
179 char cmd[PATH_MAX * 2];
180 const char *fmt;
181 FILE *f;
182 int ret;
183
184 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
185 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
186 filename);
187 if (ret <= 0 || (size_t)ret >= sizeof(cmd))
188 return -1;
189
190 pr_debug("Objdump command is: %s\n", cmd);
191
192 /* Ignore objdump errors */
193 strcat(cmd, " 2>/dev/null");
194
195 f = popen(cmd, "r");
196 if (!f) {
197 pr_debug("popen failed\n");
198 return -1;
199 }
200
201 ret = read_objdump_output(f, buf, &len, addr);
202 if (len) {
203 pr_debug("objdump read too few bytes: %zd\n", len);
204 if (!ret)
205 ret = len;
206 }
207
208 pclose(f);
209
210 return ret;
211}
212
213static void dump_buf(unsigned char *buf, size_t len)
214{
215 size_t i;
216
217 for (i = 0; i < len; i++) {
218 pr_debug("0x%02x ", buf[i]);
219 if (i % 16 == 15)
220 pr_debug("\n");
221 }
222 pr_debug("\n");
223}
224
225static int read_object_code(u64 addr, size_t len, u8 cpumode,
226 struct thread *thread, struct state *state)
227{
228 struct addr_location al;
229 unsigned char buf1[BUFSZ];
230 unsigned char buf2[BUFSZ];
231 size_t ret_len;
232 u64 objdump_addr;
233 const char *objdump_name;
234 char decomp_name[KMOD_DECOMP_LEN];
235 int ret;
236
237 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
238
239 thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
240 if (!al.map || !al.map->dso) {
241 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
242 pr_debug("Hypervisor address can not be resolved - skipping\n");
243 return 0;
244 }
245
246 pr_debug("thread__find_addr_map failed\n");
247 return -1;
248 }
249
250 pr_debug("File is: %s\n", al.map->dso->long_name);
251
252 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
253 !dso__is_kcore(al.map->dso)) {
254 pr_debug("Unexpected kernel address - skipping\n");
255 return 0;
256 }
257
258 pr_debug("On file address is: %#"PRIx64"\n", al.addr);
259
260 if (len > BUFSZ)
261 len = BUFSZ;
262
263 /* Do not go off the map */
264 if (addr + len > al.map->end)
265 len = al.map->end - addr;
266
267 /* Read the object code using perf */
268 ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
269 al.addr, buf1, len);
270 if (ret_len != len) {
271 pr_debug("dso__data_read_offset failed\n");
272 return -1;
273 }
274
275 /*
276 * Converting addresses for use by objdump requires more information.
277 * map__load() does that. See map__rip_2objdump() for details.
278 */
279 if (map__load(al.map))
280 return -1;
281
282 /* objdump struggles with kcore - try each map only once */
283 if (dso__is_kcore(al.map->dso)) {
284 size_t d;
285
286 for (d = 0; d < state->done_cnt; d++) {
287 if (state->done[d] == al.map->start) {
288 pr_debug("kcore map tested already");
289 pr_debug(" - skipping\n");
290 return 0;
291 }
292 }
293 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
294 pr_debug("Too many kcore maps - skipping\n");
295 return 0;
296 }
297 state->done[state->done_cnt++] = al.map->start;
298 }
299
300 objdump_name = al.map->dso->long_name;
301 if (dso__needs_decompress(al.map->dso)) {
302 if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
303 decomp_name,
304 sizeof(decomp_name)) < 0) {
305 pr_debug("decompression failed\n");
306 return -1;
307 }
308
309 objdump_name = decomp_name;
310 }
311
312 /* Read the object code using objdump */
313 objdump_addr = map__rip_2objdump(al.map, al.addr);
314 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
315
316 if (dso__needs_decompress(al.map->dso))
317 unlink(objdump_name);
318
319 if (ret > 0) {
320 /*
321 * The kernel maps are inaccurate - assume objdump is right in
322 * that case.
323 */
324 if (cpumode == PERF_RECORD_MISC_KERNEL ||
325 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
326 len -= ret;
327 if (len) {
328 pr_debug("Reducing len to %zu\n", len);
329 } else if (dso__is_kcore(al.map->dso)) {
330 /*
331 * objdump cannot handle very large segments
332 * that may be found in kcore.
333 */
334 pr_debug("objdump failed for kcore");
335 pr_debug(" - skipping\n");
336 return 0;
337 } else {
338 return -1;
339 }
340 }
341 }
342 if (ret < 0) {
343 pr_debug("read_via_objdump failed\n");
344 return -1;
345 }
346
347 /* The results should be identical */
348 if (memcmp(buf1, buf2, len)) {
349 pr_debug("Bytes read differ from those read by objdump\n");
350 pr_debug("buf1 (dso):\n");
351 dump_buf(buf1, len);
352 pr_debug("buf2 (objdump):\n");
353 dump_buf(buf2, len);
354 return -1;
355 }
356 pr_debug("Bytes read match those read by objdump\n");
357
358 return 0;
359}
360
361static int process_sample_event(struct machine *machine,
362 struct perf_evlist *evlist,
363 union perf_event *event, struct state *state)
364{
365 struct perf_sample sample;
366 struct thread *thread;
367 int ret;
368
369 if (perf_evlist__parse_sample(evlist, event, &sample)) {
370 pr_debug("perf_evlist__parse_sample failed\n");
371 return -1;
372 }
373
374 thread = machine__findnew_thread(machine, sample.pid, sample.tid);
375 if (!thread) {
376 pr_debug("machine__findnew_thread failed\n");
377 return -1;
378 }
379
380 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
381 thread__put(thread);
382 return ret;
383}
384
385static int process_event(struct machine *machine, struct perf_evlist *evlist,
386 union perf_event *event, struct state *state)
387{
388 if (event->header.type == PERF_RECORD_SAMPLE)
389 return process_sample_event(machine, evlist, event, state);
390
391 if (event->header.type == PERF_RECORD_THROTTLE ||
392 event->header.type == PERF_RECORD_UNTHROTTLE)
393 return 0;
394
395 if (event->header.type < PERF_RECORD_MAX) {
396 int ret;
397
398 ret = machine__process_event(machine, event, NULL);
399 if (ret < 0)
400 pr_debug("machine__process_event failed, event type %u\n",
401 event->header.type);
402 return ret;
403 }
404
405 return 0;
406}
407
408static int process_events(struct machine *machine, struct perf_evlist *evlist,
409 struct state *state)
410{
411 union perf_event *event;
412 struct perf_mmap *md;
413 int i, ret;
414
415 for (i = 0; i < evlist->nr_mmaps; i++) {
416 md = &evlist->mmap[i];
417 if (perf_mmap__read_init(md) < 0)
418 continue;
419
420 while ((event = perf_mmap__read_event(md)) != NULL) {
421 ret = process_event(machine, evlist, event, state);
422 perf_mmap__consume(md);
423 if (ret < 0)
424 return ret;
425 }
426 perf_mmap__read_done(md);
427 }
428 return 0;
429}
430
431static int comp(const void *a, const void *b)
432{
433 return *(int *)a - *(int *)b;
434}
435
436static void do_sort_something(void)
437{
438 int buf[40960], i;
439
440 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
441 buf[i] = ARRAY_SIZE(buf) - i - 1;
442
443 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
444
445 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
446 if (buf[i] != i) {
447 pr_debug("qsort failed\n");
448 break;
449 }
450 }
451}
452
453static void sort_something(void)
454{
455 int i;
456
457 for (i = 0; i < 10; i++)
458 do_sort_something();
459}
460
461static void syscall_something(void)
462{
463 int pipefd[2];
464 int i;
465
466 for (i = 0; i < 1000; i++) {
467 if (pipe(pipefd) < 0) {
468 pr_debug("pipe failed\n");
469 break;
470 }
471 close(pipefd[1]);
472 close(pipefd[0]);
473 }
474}
475
476static void fs_something(void)
477{
478 const char *test_file_name = "temp-perf-code-reading-test-file--";
479 FILE *f;
480 int i;
481
482 for (i = 0; i < 1000; i++) {
483 f = fopen(test_file_name, "w+");
484 if (f) {
485 fclose(f);
486 unlink(test_file_name);
487 }
488 }
489}
490
491static const char *do_determine_event(bool excl_kernel)
492{
493 const char *event = excl_kernel ? "cycles:u" : "cycles";
494
495#ifdef __s390x__
496 char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
497 unsigned int family;
498 int ret, cpum_cf_a;
499
500 if (get_cpuid(cpuid, sizeof(cpuid)))
501 goto out_clocks;
502 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
503 model, cpum_cf_v, &cpum_cf_a);
504 if (ret != 5) /* Not available */
505 goto out_clocks;
506 if (excl_kernel && (cpum_cf_a & 4))
507 return event;
508 if (!excl_kernel && (cpum_cf_a & 2))
509 return event;
510
511 /* Fall through: missing authorization */
512out_clocks:
513 event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
514
515#endif
516 return event;
517}
518
519static void do_something(void)
520{
521 fs_something();
522
523 sort_something();
524
525 syscall_something();
526}
527
528enum {
529 TEST_CODE_READING_OK,
530 TEST_CODE_READING_NO_VMLINUX,
531 TEST_CODE_READING_NO_KCORE,
532 TEST_CODE_READING_NO_ACCESS,
533 TEST_CODE_READING_NO_KERNEL_OBJ,
534};
535
536static int do_test_code_reading(bool try_kcore)
537{
538 struct machine *machine;
539 struct thread *thread;
540 struct record_opts opts = {
541 .mmap_pages = UINT_MAX,
542 .user_freq = UINT_MAX,
543 .user_interval = ULLONG_MAX,
544 .freq = 500,
545 .target = {
546 .uses_mmap = true,
547 },
548 };
549 struct state state = {
550 .done_cnt = 0,
551 };
552 struct thread_map *threads = NULL;
553 struct cpu_map *cpus = NULL;
554 struct perf_evlist *evlist = NULL;
555 struct perf_evsel *evsel = NULL;
556 int err = -1, ret;
557 pid_t pid;
558 struct map *map;
559 bool have_vmlinux, have_kcore, excl_kernel = false;
560
561 pid = getpid();
562
563 machine = machine__new_host();
564
565 ret = machine__create_kernel_maps(machine);
566 if (ret < 0) {
567 pr_debug("machine__create_kernel_maps failed\n");
568 goto out_err;
569 }
570
571 /* Force the use of kallsyms instead of vmlinux to try kcore */
572 if (try_kcore)
573 symbol_conf.kallsyms_name = "/proc/kallsyms";
574
575 /* Load kernel map */
576 map = machine__kernel_map(machine);
577 ret = map__load(map);
578 if (ret < 0) {
579 pr_debug("map__load failed\n");
580 goto out_err;
581 }
582 have_vmlinux = dso__is_vmlinux(map->dso);
583 have_kcore = dso__is_kcore(map->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 excl_kernel = true;
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, false, 500);
601 if (ret < 0) {
602 pr_debug("perf_event__synthesize_thread_map failed\n");
603 goto out_err;
604 }
605
606 thread = machine__findnew_thread(machine, pid, pid);
607 if (!thread) {
608 pr_debug("machine__findnew_thread failed\n");
609 goto out_put;
610 }
611
612 cpus = cpu_map__new(NULL);
613 if (!cpus) {
614 pr_debug("cpu_map__new failed\n");
615 goto out_put;
616 }
617
618 while (1) {
619 const char *str;
620
621 evlist = perf_evlist__new();
622 if (!evlist) {
623 pr_debug("perf_evlist__new failed\n");
624 goto out_put;
625 }
626
627 perf_evlist__set_maps(evlist, cpus, threads);
628
629 str = do_determine_event(excl_kernel);
630 pr_debug("Parsing event '%s'\n", str);
631 ret = parse_events(evlist, str, NULL);
632 if (ret < 0) {
633 pr_debug("parse_events failed\n");
634 goto out_put;
635 }
636
637 perf_evlist__config(evlist, &opts, NULL);
638
639 evsel = perf_evlist__first(evlist);
640
641 evsel->attr.comm = 1;
642 evsel->attr.disabled = 1;
643 evsel->attr.enable_on_exec = 0;
644
645 ret = perf_evlist__open(evlist);
646 if (ret < 0) {
647 if (!excl_kernel) {
648 excl_kernel = true;
649 /*
650 * Both cpus and threads are now owned by evlist
651 * and will be freed by following perf_evlist__set_maps
652 * call. Getting refference to keep them alive.
653 */
654 cpu_map__get(cpus);
655 thread_map__get(threads);
656 perf_evlist__set_maps(evlist, NULL, NULL);
657 perf_evlist__delete(evlist);
658 evlist = NULL;
659 continue;
660 }
661
662 if (verbose > 0) {
663 char errbuf[512];
664 perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
665 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
666 }
667
668 goto out_put;
669 }
670 break;
671 }
672
673 ret = perf_evlist__mmap(evlist, UINT_MAX);
674 if (ret < 0) {
675 pr_debug("perf_evlist__mmap failed\n");
676 goto out_put;
677 }
678
679 perf_evlist__enable(evlist);
680
681 do_something();
682
683 perf_evlist__disable(evlist);
684
685 ret = process_events(machine, evlist, &state);
686 if (ret < 0)
687 goto out_put;
688
689 if (!have_vmlinux && !have_kcore && !try_kcore)
690 err = TEST_CODE_READING_NO_KERNEL_OBJ;
691 else if (!have_vmlinux && !try_kcore)
692 err = TEST_CODE_READING_NO_VMLINUX;
693 else if (excl_kernel)
694 err = TEST_CODE_READING_NO_ACCESS;
695 else
696 err = TEST_CODE_READING_OK;
697out_put:
698 thread__put(thread);
699out_err:
700
701 if (evlist) {
702 perf_evlist__delete(evlist);
703 } else {
704 cpu_map__put(cpus);
705 thread_map__put(threads);
706 }
707 machine__delete_threads(machine);
708 machine__delete(machine);
709
710 return err;
711}
712
713int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused)
714{
715 int ret;
716
717 ret = do_test_code_reading(false);
718 if (!ret)
719 ret = do_test_code_reading(true);
720
721 switch (ret) {
722 case TEST_CODE_READING_OK:
723 return 0;
724 case TEST_CODE_READING_NO_VMLINUX:
725 pr_debug("no vmlinux\n");
726 return 0;
727 case TEST_CODE_READING_NO_KCORE:
728 pr_debug("no kcore\n");
729 return 0;
730 case TEST_CODE_READING_NO_ACCESS:
731 pr_debug("no access\n");
732 return 0;
733 case TEST_CODE_READING_NO_KERNEL_OBJ:
734 pr_debug("no kernel obj\n");
735 return 0;
736 default:
737 return -1;
738 };
739}