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

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

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