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