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TOMOYO Linux Cross Reference
Linux/tools/perf/tests/code-reading.c

Version: ~ [ linux-5.12 ] ~ [ linux-5.11.16 ] ~ [ linux-5.10.32 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.114 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.188 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.231 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.267 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.267 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

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

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