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 void 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;
41
42	/* Skip to a colon */
43	p = strchr(line, ':');
44	if (!p)
45		return;
46	i = p + 1 - line;
47
48	/* Read bytes */
49	while (*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		*len -= 1;
71	}
72}
73
74static int read_objdump_output(FILE *f, void **buf, size_t *len)
75{
76	char *line = NULL;
77	size_t line_len;
78	ssize_t ret;
79	int err = 0;
80
81	while (1) {
82		ret = getline(&line, &line_len, f);
83		if (feof(f))
84			break;
85		if (ret < 0) {
86			pr_debug("getline failed\n");
87			err = -1;
88			break;
89		}
90		read_objdump_line(line, ret, buf, len);
91	}
92
93	free(line);
94
95	return err;
96}
97
98static int read_via_objdump(const char *filename, u64 addr, void *buf,
99			    size_t len)
100{
101	char cmd[PATH_MAX * 2];
102	const char *fmt;
103	FILE *f;
104	int ret;
105
106	fmt = "%s -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
107	ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
108		       filename);
109	if (ret <= 0 || (size_t)ret >= sizeof(cmd))
110		return -1;
111
112	pr_debug("Objdump command is: %s\n", cmd);
113
114	/* Ignore objdump errors */
115	strcat(cmd, " 2>/dev/null");
116
117	f = popen(cmd, "r");
118	if (!f) {
119		pr_debug("popen failed\n");
120		return -1;
121	}
122
123	ret = read_objdump_output(f, &buf, &len);
124	if (len) {
125		pr_debug("objdump read too few bytes\n");
126		if (!ret)
127			ret = len;
128	}
129
130	pclose(f);
131
132	return ret;
133}
134
135static int read_object_code(u64 addr, size_t len, u8 cpumode,
136			    struct thread *thread, struct state *state)
137{
138	struct addr_location al;
139	unsigned char buf1[BUFSZ];
140	unsigned char buf2[BUFSZ];
141	size_t ret_len;
142	u64 objdump_addr;
143	int ret;
144
145	pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
146
147	thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al);
148	if (!al.map || !al.map->dso) {
149		pr_debug("thread__find_addr_map failed\n");
150		return -1;
151	}
152
153	pr_debug("File is: %s\n", al.map->dso->long_name);
154
155	if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
156	    !dso__is_kcore(al.map->dso)) {
157		pr_debug("Unexpected kernel address - skipping\n");
158		return 0;
159	}
160
161	pr_debug("On file address is: %#"PRIx64"\n", al.addr);
162
163	if (len > BUFSZ)
164		len = BUFSZ;
165
166	/* Do not go off the map */
167	if (addr + len > al.map->end)
168		len = al.map->end - addr;
169
170	/* Read the object code using perf */
171	ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine,
172					al.addr, buf1, len);
173	if (ret_len != len) {
174		pr_debug("dso__data_read_offset failed\n");
175		return -1;
176	}
177
178	/*
179	 * Converting addresses for use by objdump requires more information.
180	 * map__load() does that.  See map__rip_2objdump() for details.
181	 */
182	if (map__load(al.map, NULL))
183		return -1;
184
185	/* objdump struggles with kcore - try each map only once */
186	if (dso__is_kcore(al.map->dso)) {
187		size_t d;
188
189		for (d = 0; d < state->done_cnt; d++) {
190			if (state->done[d] == al.map->start) {
191				pr_debug("kcore map tested already");
192				pr_debug(" - skipping\n");
193				return 0;
194			}
195		}
196		if (state->done_cnt >= ARRAY_SIZE(state->done)) {
197			pr_debug("Too many kcore maps - skipping\n");
198			return 0;
199		}
200		state->done[state->done_cnt++] = al.map->start;
201	}
202
203	/* Read the object code using objdump */
204	objdump_addr = map__rip_2objdump(al.map, al.addr);
205	ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
206	if (ret > 0) {
207		/*
208		 * The kernel maps are inaccurate - assume objdump is right in
209		 * that case.
210		 */
211		if (cpumode == PERF_RECORD_MISC_KERNEL ||
212		    cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
213			len -= ret;
214			if (len) {
215				pr_debug("Reducing len to %zu\n", len);
216			} else if (dso__is_kcore(al.map->dso)) {
217				/*
218				 * objdump cannot handle very large segments
219				 * that may be found in kcore.
220				 */
221				pr_debug("objdump failed for kcore");
222				pr_debug(" - skipping\n");
223				return 0;
224			} else {
225				return -1;
226			}
227		}
228	}
229	if (ret < 0) {
230		pr_debug("read_via_objdump failed\n");
231		return -1;
232	}
233
234	/* The results should be identical */
235	if (memcmp(buf1, buf2, len)) {
236		pr_debug("Bytes read differ from those read by objdump\n");
237		return -1;
238	}
239	pr_debug("Bytes read match those read by objdump\n");
240
241	return 0;
242}
243
244static int process_sample_event(struct machine *machine,
245				struct perf_evlist *evlist,
246				union perf_event *event, struct state *state)
247{
248	struct perf_sample sample;
249	struct thread *thread;
250	u8 cpumode;
251
252	if (perf_evlist__parse_sample(evlist, event, &sample)) {
253		pr_debug("perf_evlist__parse_sample failed\n");
254		return -1;
255	}
256
257	thread = machine__findnew_thread(machine, sample.pid, sample.tid);
258	if (!thread) {
259		pr_debug("machine__findnew_thread failed\n");
260		return -1;
261	}
262
263	cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
264
265	return read_object_code(sample.ip, READLEN, cpumode, thread, state);
266}
267
268static int process_event(struct machine *machine, struct perf_evlist *evlist,
269			 union perf_event *event, struct state *state)
270{
271	if (event->header.type == PERF_RECORD_SAMPLE)
272		return process_sample_event(machine, evlist, event, state);
273
274	if (event->header.type == PERF_RECORD_THROTTLE ||
275	    event->header.type == PERF_RECORD_UNTHROTTLE)
276		return 0;
277
278	if (event->header.type < PERF_RECORD_MAX) {
279		int ret;
280
281		ret = machine__process_event(machine, event, NULL);
282		if (ret < 0)
283			pr_debug("machine__process_event failed, event type %u\n",
284				 event->header.type);
285		return ret;
286	}
287
288	return 0;
289}
290
291static int process_events(struct machine *machine, struct perf_evlist *evlist,
292			  struct state *state)
293{
294	union perf_event *event;
295	int i, ret;
296
297	for (i = 0; i < evlist->nr_mmaps; i++) {
298		while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) {
299			ret = process_event(machine, evlist, event, state);
300			perf_evlist__mmap_consume(evlist, i);
301			if (ret < 0)
302				return ret;
303		}
304	}
305	return 0;
306}
307
308static int comp(const void *a, const void *b)
309{
310	return *(int *)a - *(int *)b;
311}
312
313static void do_sort_something(void)
314{
315	int buf[40960], i;
316
317	for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
318		buf[i] = ARRAY_SIZE(buf) - i - 1;
319
320	qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
321
322	for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
323		if (buf[i] != i) {
324			pr_debug("qsort failed\n");
325			break;
326		}
327	}
328}
329
330static void sort_something(void)
331{
332	int i;
333
334	for (i = 0; i < 10; i++)
335		do_sort_something();
336}
337
338static void syscall_something(void)
339{
340	int pipefd[2];
341	int i;
342
343	for (i = 0; i < 1000; i++) {
344		if (pipe(pipefd) < 0) {
345			pr_debug("pipe failed\n");
346			break;
347		}
348		close(pipefd[1]);
349		close(pipefd[0]);
350	}
351}
352
353static void fs_something(void)
354{
355	const char *test_file_name = "temp-perf-code-reading-test-file--";
356	FILE *f;
357	int i;
358
359	for (i = 0; i < 1000; i++) {
360		f = fopen(test_file_name, "w+");
361		if (f) {
362			fclose(f);
363			unlink(test_file_name);
364		}
365	}
366}
367
368static void do_something(void)
369{
370	fs_something();
371
372	sort_something();
373
374	syscall_something();
375}
376
377enum {
378	TEST_CODE_READING_OK,
379	TEST_CODE_READING_NO_VMLINUX,
380	TEST_CODE_READING_NO_KCORE,
381	TEST_CODE_READING_NO_ACCESS,
382	TEST_CODE_READING_NO_KERNEL_OBJ,
383};
384
385static int do_test_code_reading(bool try_kcore)
386{
387	struct machines machines;
388	struct machine *machine;
389	struct thread *thread;
390	struct record_opts opts = {
391		.mmap_pages	     = UINT_MAX,
392		.user_freq	     = UINT_MAX,
393		.user_interval	     = ULLONG_MAX,
394		.freq		     = 4000,
395		.target		     = {
396			.uses_mmap   = true,
397		},
398	};
399	struct state state = {
400		.done_cnt = 0,
401	};
402	struct thread_map *threads = NULL;
403	struct cpu_map *cpus = NULL;
404	struct perf_evlist *evlist = NULL;
405	struct perf_evsel *evsel = NULL;
406	int err = -1, ret;
407	pid_t pid;
408	struct map *map;
409	bool have_vmlinux, have_kcore, excl_kernel = false;
410
411	pid = getpid();
412
413	machines__init(&machines);
414	machine = &machines.host;
415
416	ret = machine__create_kernel_maps(machine);
417	if (ret < 0) {
418		pr_debug("machine__create_kernel_maps failed\n");
419		goto out_err;
420	}
421
422	/* Force the use of kallsyms instead of vmlinux to try kcore */
423	if (try_kcore)
424		symbol_conf.kallsyms_name = "/proc/kallsyms";
425
426	/* Load kernel map */
427	map = machine->vmlinux_maps[MAP__FUNCTION];
428	ret = map__load(map, NULL);
429	if (ret < 0) {
430		pr_debug("map__load failed\n");
431		goto out_err;
432	}
433	have_vmlinux = dso__is_vmlinux(map->dso);
434	have_kcore = dso__is_kcore(map->dso);
435
436	/* 2nd time through we just try kcore */
437	if (try_kcore && !have_kcore)
438		return TEST_CODE_READING_NO_KCORE;
439
440	/* No point getting kernel events if there is no kernel object */
441	if (!have_vmlinux && !have_kcore)
442		excl_kernel = true;
443
444	threads = thread_map__new_by_tid(pid);
445	if (!threads) {
446		pr_debug("thread_map__new_by_tid failed\n");
447		goto out_err;
448	}
449
450	ret = perf_event__synthesize_thread_map(NULL, threads,
451						perf_event__process, machine, false);
452	if (ret < 0) {
453		pr_debug("perf_event__synthesize_thread_map failed\n");
454		goto out_err;
455	}
456
457	thread = machine__findnew_thread(machine, pid, pid);
458	if (!thread) {
459		pr_debug("machine__findnew_thread failed\n");
460		goto out_err;
461	}
462
463	cpus = cpu_map__new(NULL);
464	if (!cpus) {
465		pr_debug("cpu_map__new failed\n");
466		goto out_err;
467	}
468
469	while (1) {
470		const char *str;
471
472		evlist = perf_evlist__new();
473		if (!evlist) {
474			pr_debug("perf_evlist__new failed\n");
475			goto out_err;
476		}
477
478		perf_evlist__set_maps(evlist, cpus, threads);
479
480		if (excl_kernel)
481			str = "cycles:u";
482		else
483			str = "cycles";
484		pr_debug("Parsing event '%s'\n", str);
485		ret = parse_events(evlist, str);
486		if (ret < 0) {
487			pr_debug("parse_events failed\n");
488			goto out_err;
489		}
490
491		perf_evlist__config(evlist, &opts);
492
493		evsel = perf_evlist__first(evlist);
494
495		evsel->attr.comm = 1;
496		evsel->attr.disabled = 1;
497		evsel->attr.enable_on_exec = 0;
498
499		ret = perf_evlist__open(evlist);
500		if (ret < 0) {
501			if (!excl_kernel) {
502				excl_kernel = true;
503				perf_evlist__set_maps(evlist, NULL, NULL);
504				perf_evlist__delete(evlist);
505				evlist = NULL;
506				continue;
507			}
508			pr_debug("perf_evlist__open failed\n");
509			goto out_err;
510		}
511		break;
512	}
513
514	ret = perf_evlist__mmap(evlist, UINT_MAX, false);
515	if (ret < 0) {
516		pr_debug("perf_evlist__mmap failed\n");
517		goto out_err;
518	}
519
520	perf_evlist__enable(evlist);
521
522	do_something();
523
524	perf_evlist__disable(evlist);
525
526	ret = process_events(machine, evlist, &state);
527	if (ret < 0)
528		goto out_err;
529
530	if (!have_vmlinux && !have_kcore && !try_kcore)
531		err = TEST_CODE_READING_NO_KERNEL_OBJ;
532	else if (!have_vmlinux && !try_kcore)
533		err = TEST_CODE_READING_NO_VMLINUX;
534	else if (excl_kernel)
535		err = TEST_CODE_READING_NO_ACCESS;
536	else
537		err = TEST_CODE_READING_OK;
538out_err:
539	if (evlist) {
540		perf_evlist__delete(evlist);
541	} else {
542		cpu_map__delete(cpus);
543		thread_map__delete(threads);
544	}
545	machines__destroy_kernel_maps(&machines);
546	machine__delete_threads(machine);
547	machines__exit(&machines);
548
549	return err;
550}
551
552int test__code_reading(void)
553{
554	int ret;
555
556	ret = do_test_code_reading(false);
557	if (!ret)
558		ret = do_test_code_reading(true);
559
560	switch (ret) {
561	case TEST_CODE_READING_OK:
562		return 0;
563	case TEST_CODE_READING_NO_VMLINUX:
564		fprintf(stderr, " (no vmlinux)");
565		return 0;
566	case TEST_CODE_READING_NO_KCORE:
567		fprintf(stderr, " (no kcore)");
568		return 0;
569	case TEST_CODE_READING_NO_ACCESS:
570		fprintf(stderr, " (no access)");
571		return 0;
572	case TEST_CODE_READING_NO_KERNEL_OBJ:
573		fprintf(stderr, " (no kernel obj)");
574		return 0;
575	default:
576		return -1;
577	};
578}
579