1 // SPDX-License-Identifier: GPL-2.0
3 #include <linux/kernel.h>
4 #include <linux/types.h>
10 #include <sys/param.h>
11 #include <perf/cpumap.h>
12 #include <perf/evlist.h>
13 #include <perf/mmap.h>
18 #include "parse-events.h"
19 #include "trace-event.h"
22 #include "thread_map.h"
28 #include "util/mmap.h"
29 #include "util/synthetic-events.h"
34 #include <linux/ctype.h>
44 static unsigned int hex(char c)
46 if (c >= '0' && c <= '9')
48 if (c >= 'a' && c <= 'f')
53 static size_t read_objdump_chunk(const char **line, unsigned char **buf,
56 size_t bytes_read = 0;
57 unsigned char *chunk_start = *buf;
60 while (*buf_len > 0) {
63 /* Get 2 hex digits */
71 /* Store byte and advance buf */
72 **buf = (hex(c1) << 4) | hex(c2);
83 * objdump will display raw insn as LE if code endian
84 * is LE and bytes_per_chunk > 1. In that case reverse
85 * the chunk we just read.
87 * see disassemble_bytes() at binutils/objdump.c for details
88 * how objdump chooses display endian)
90 if (bytes_read > 1 && !bigendian()) {
91 unsigned char *chunk_end = chunk_start + bytes_read - 1;
94 while (chunk_start < chunk_end) {
96 *chunk_start = *chunk_end;
106 static size_t read_objdump_line(const char *line, unsigned char *buf,
110 size_t ret, bytes_read = 0;
112 /* Skip to a colon */
113 p = strchr(line, ':');
118 /* Skip initial spaces */
126 ret = read_objdump_chunk(&p, &buf, &buf_len);
131 /* return number of successfully read bytes */
135 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
138 size_t line_len, off_last = 0;
141 u64 addr, last_addr = start_addr;
143 while (off_last < *len) {
144 size_t off, read_bytes, written_bytes;
145 unsigned char tmp[BUFSZ];
147 ret = getline(&line, &line_len, f);
151 pr_debug("getline failed\n");
156 /* read objdump data into temporary buffer */
157 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
161 if (sscanf(line, "%"PRIx64, &addr) != 1)
163 if (addr < last_addr) {
164 pr_debug("addr going backwards, read beyond section?\n");
169 /* copy it from temporary buffer to 'buf' according
170 * to address on current objdump line */
171 off = addr - start_addr;
174 written_bytes = MIN(read_bytes, *len - off);
175 memcpy(buf + off, tmp, written_bytes);
176 off_last = off + written_bytes;
179 /* len returns number of bytes that could not be read */
187 static int read_via_objdump(const char *filename, u64 addr, void *buf,
190 char cmd[PATH_MAX * 2];
195 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
196 ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len,
198 if (ret <= 0 || (size_t)ret >= sizeof(cmd))
201 pr_debug("Objdump command is: %s\n", cmd);
203 /* Ignore objdump errors */
204 strcat(cmd, " 2>/dev/null");
208 pr_debug("popen failed\n");
212 ret = read_objdump_output(f, buf, &len, addr);
214 pr_debug("objdump read too few bytes: %zd\n", len);
224 static void dump_buf(unsigned char *buf, size_t len)
228 for (i = 0; i < len; i++) {
229 pr_debug("0x%02x ", buf[i]);
236 static int read_object_code(u64 addr, size_t len, u8 cpumode,
237 struct thread *thread, struct state *state)
239 struct addr_location al;
240 unsigned char buf1[BUFSZ];
241 unsigned char buf2[BUFSZ];
244 const char *objdump_name;
245 char decomp_name[KMOD_DECOMP_LEN];
249 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
251 if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) {
252 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
253 pr_debug("Hypervisor address can not be resolved - skipping\n");
257 pr_debug("thread__find_map failed\n");
261 pr_debug("File is: %s\n", al.map->dso->long_name);
263 if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS &&
264 !dso__is_kcore(al.map->dso)) {
265 pr_debug("Unexpected kernel address - skipping\n");
269 pr_debug("On file address is: %#"PRIx64"\n", al.addr);
274 /* Do not go off the map */
275 if (addr + len > al.map->end)
276 len = al.map->end - addr;
278 /* Read the object code using perf */
279 ret_len = dso__data_read_offset(al.map->dso, thread->maps->machine,
281 if (ret_len != len) {
282 pr_debug("dso__data_read_offset failed\n");
287 * Converting addresses for use by objdump requires more information.
288 * map__load() does that. See map__rip_2objdump() for details.
290 if (map__load(al.map))
293 /* objdump struggles with kcore - try each map only once */
294 if (dso__is_kcore(al.map->dso)) {
297 for (d = 0; d < state->done_cnt; d++) {
298 if (state->done[d] == al.map->start) {
299 pr_debug("kcore map tested already");
300 pr_debug(" - skipping\n");
304 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
305 pr_debug("Too many kcore maps - skipping\n");
308 state->done[state->done_cnt++] = al.map->start;
311 objdump_name = al.map->dso->long_name;
312 if (dso__needs_decompress(al.map->dso)) {
313 if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
315 sizeof(decomp_name)) < 0) {
316 pr_debug("decompression failed\n");
321 objdump_name = decomp_name;
324 /* Read the object code using objdump */
325 objdump_addr = map__rip_2objdump(al.map, al.addr);
326 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
329 unlink(objdump_name);
333 * The kernel maps are inaccurate - assume objdump is right in
336 if (cpumode == PERF_RECORD_MISC_KERNEL ||
337 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
340 pr_debug("Reducing len to %zu\n", len);
341 } else if (dso__is_kcore(al.map->dso)) {
343 * objdump cannot handle very large segments
344 * that may be found in kcore.
346 pr_debug("objdump failed for kcore");
347 pr_debug(" - skipping\n");
355 pr_debug("read_via_objdump failed\n");
359 /* The results should be identical */
360 if (memcmp(buf1, buf2, len)) {
361 pr_debug("Bytes read differ from those read by objdump\n");
362 pr_debug("buf1 (dso):\n");
364 pr_debug("buf2 (objdump):\n");
368 pr_debug("Bytes read match those read by objdump\n");
373 static int process_sample_event(struct machine *machine,
374 struct evlist *evlist,
375 union perf_event *event, struct state *state)
377 struct perf_sample sample;
378 struct thread *thread;
381 if (evlist__parse_sample(evlist, event, &sample)) {
382 pr_debug("evlist__parse_sample failed\n");
386 thread = machine__findnew_thread(machine, sample.pid, sample.tid);
388 pr_debug("machine__findnew_thread failed\n");
392 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
397 static int process_event(struct machine *machine, struct evlist *evlist,
398 union perf_event *event, struct state *state)
400 if (event->header.type == PERF_RECORD_SAMPLE)
401 return process_sample_event(machine, evlist, event, state);
403 if (event->header.type == PERF_RECORD_THROTTLE ||
404 event->header.type == PERF_RECORD_UNTHROTTLE)
407 if (event->header.type < PERF_RECORD_MAX) {
410 ret = machine__process_event(machine, event, NULL);
412 pr_debug("machine__process_event failed, event type %u\n",
420 static int process_events(struct machine *machine, struct evlist *evlist,
423 union perf_event *event;
427 for (i = 0; i < evlist->core.nr_mmaps; i++) {
428 md = &evlist->mmap[i];
429 if (perf_mmap__read_init(&md->core) < 0)
432 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
433 ret = process_event(machine, evlist, event, state);
434 perf_mmap__consume(&md->core);
438 perf_mmap__read_done(&md->core);
443 static int comp(const void *a, const void *b)
445 return *(int *)a - *(int *)b;
448 static void do_sort_something(void)
452 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
453 buf[i] = ARRAY_SIZE(buf) - i - 1;
455 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
457 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
459 pr_debug("qsort failed\n");
465 static void sort_something(void)
469 for (i = 0; i < 10; i++)
473 static void syscall_something(void)
478 for (i = 0; i < 1000; i++) {
479 if (pipe(pipefd) < 0) {
480 pr_debug("pipe failed\n");
488 static void fs_something(void)
490 const char *test_file_name = "temp-perf-code-reading-test-file--";
494 for (i = 0; i < 1000; i++) {
495 f = fopen(test_file_name, "w+");
498 unlink(test_file_name);
504 #include "header.h" // for get_cpuid()
507 static const char *do_determine_event(bool excl_kernel)
509 const char *event = excl_kernel ? "cycles:u" : "cycles";
512 char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
516 if (get_cpuid(cpuid, sizeof(cpuid)))
518 ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
519 model, cpum_cf_v, &cpum_cf_a);
520 if (ret != 5) /* Not available */
522 if (excl_kernel && (cpum_cf_a & 4))
524 if (!excl_kernel && (cpum_cf_a & 2))
527 /* Fall through: missing authorization */
529 event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
535 static void do_something(void)
545 TEST_CODE_READING_OK,
546 TEST_CODE_READING_NO_VMLINUX,
547 TEST_CODE_READING_NO_KCORE,
548 TEST_CODE_READING_NO_ACCESS,
549 TEST_CODE_READING_NO_KERNEL_OBJ,
552 static int do_test_code_reading(bool try_kcore)
554 struct machine *machine;
555 struct thread *thread;
556 struct record_opts opts = {
557 .mmap_pages = UINT_MAX,
558 .user_freq = UINT_MAX,
559 .user_interval = ULLONG_MAX,
565 struct state state = {
568 struct perf_thread_map *threads = NULL;
569 struct perf_cpu_map *cpus = NULL;
570 struct evlist *evlist = NULL;
571 struct evsel *evsel = NULL;
575 bool have_vmlinux, have_kcore, excl_kernel = false;
579 machine = machine__new_host();
580 machine->env = &perf_env;
582 ret = machine__create_kernel_maps(machine);
584 pr_debug("machine__create_kernel_maps failed\n");
588 /* Force the use of kallsyms instead of vmlinux to try kcore */
590 symbol_conf.kallsyms_name = "/proc/kallsyms";
592 /* Load kernel map */
593 map = machine__kernel_map(machine);
594 ret = map__load(map);
596 pr_debug("map__load failed\n");
599 have_vmlinux = dso__is_vmlinux(map->dso);
600 have_kcore = dso__is_kcore(map->dso);
602 /* 2nd time through we just try kcore */
603 if (try_kcore && !have_kcore)
604 return TEST_CODE_READING_NO_KCORE;
606 /* No point getting kernel events if there is no kernel object */
607 if (!have_vmlinux && !have_kcore)
610 threads = thread_map__new_by_tid(pid);
612 pr_debug("thread_map__new_by_tid failed\n");
616 ret = perf_event__synthesize_thread_map(NULL, threads,
617 perf_event__process, machine, false);
619 pr_debug("perf_event__synthesize_thread_map failed\n");
623 thread = machine__findnew_thread(machine, pid, pid);
625 pr_debug("machine__findnew_thread failed\n");
629 cpus = perf_cpu_map__new(NULL);
631 pr_debug("perf_cpu_map__new failed\n");
638 evlist = evlist__new();
640 pr_debug("evlist__new failed\n");
644 perf_evlist__set_maps(&evlist->core, cpus, threads);
646 str = do_determine_event(excl_kernel);
647 pr_debug("Parsing event '%s'\n", str);
648 ret = parse_events(evlist, str, NULL);
650 pr_debug("parse_events failed\n");
654 evlist__config(evlist, &opts, NULL);
656 evsel = evlist__first(evlist);
658 evsel->core.attr.comm = 1;
659 evsel->core.attr.disabled = 1;
660 evsel->core.attr.enable_on_exec = 0;
662 ret = evlist__open(evlist);
667 * Both cpus and threads are now owned by evlist
668 * and will be freed by following perf_evlist__set_maps
669 * call. Getting refference to keep them alive.
671 perf_cpu_map__get(cpus);
672 perf_thread_map__get(threads);
673 perf_evlist__set_maps(&evlist->core, NULL, NULL);
674 evlist__delete(evlist);
681 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
682 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
690 ret = evlist__mmap(evlist, UINT_MAX);
692 pr_debug("evlist__mmap failed\n");
696 evlist__enable(evlist);
700 evlist__disable(evlist);
702 ret = process_events(machine, evlist, &state);
706 if (!have_vmlinux && !have_kcore && !try_kcore)
707 err = TEST_CODE_READING_NO_KERNEL_OBJ;
708 else if (!have_vmlinux && !try_kcore)
709 err = TEST_CODE_READING_NO_VMLINUX;
710 else if (excl_kernel)
711 err = TEST_CODE_READING_NO_ACCESS;
713 err = TEST_CODE_READING_OK;
719 evlist__delete(evlist);
721 perf_cpu_map__put(cpus);
722 perf_thread_map__put(threads);
724 machine__delete_threads(machine);
725 machine__delete(machine);
730 int test__code_reading(struct test *test __maybe_unused, int subtest __maybe_unused)
734 ret = do_test_code_reading(false);
736 ret = do_test_code_reading(true);
739 case TEST_CODE_READING_OK:
741 case TEST_CODE_READING_NO_VMLINUX:
742 pr_debug("no vmlinux\n");
744 case TEST_CODE_READING_NO_KCORE:
745 pr_debug("no kcore\n");
747 case TEST_CODE_READING_NO_ACCESS:
748 pr_debug("no access\n");
750 case TEST_CODE_READING_NO_KERNEL_OBJ:
751 pr_debug("no kernel obj\n");