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"
21 #include "thread_map.h"
27 #include "util/mmap.h"
28 #include "util/string2.h"
29 #include "util/synthetic-events.h"
30 #include "util/util.h"
35 #include <linux/ctype.h>
45 static size_t read_objdump_chunk(const char **line, unsigned char **buf,
48 size_t bytes_read = 0;
49 unsigned char *chunk_start = *buf;
52 while (*buf_len > 0) {
55 /* Get 2 hex digits */
63 /* Store byte and advance buf */
64 **buf = (hex(c1) << 4) | hex(c2);
75 * objdump will display raw insn as LE if code endian
76 * is LE and bytes_per_chunk > 1. In that case reverse
77 * the chunk we just read.
79 * see disassemble_bytes() at binutils/objdump.c for details
80 * how objdump chooses display endian)
82 if (bytes_read > 1 && !host_is_bigendian()) {
83 unsigned char *chunk_end = chunk_start + bytes_read - 1;
86 while (chunk_start < chunk_end) {
88 *chunk_start = *chunk_end;
98 static size_t read_objdump_line(const char *line, unsigned char *buf,
102 size_t ret, bytes_read = 0;
104 /* Skip to a colon */
105 p = strchr(line, ':');
110 /* Skip initial spaces */
118 ret = read_objdump_chunk(&p, &buf, &buf_len);
123 /* return number of successfully read bytes */
127 static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
130 size_t line_len, off_last = 0;
133 u64 addr, last_addr = start_addr;
135 while (off_last < *len) {
136 size_t off, read_bytes, written_bytes;
137 unsigned char tmp[BUFSZ];
139 ret = getline(&line, &line_len, f);
143 pr_debug("getline failed\n");
148 /* read objdump data into temporary buffer */
149 read_bytes = read_objdump_line(line, tmp, sizeof(tmp));
153 if (sscanf(line, "%"PRIx64, &addr) != 1)
155 if (addr < last_addr) {
156 pr_debug("addr going backwards, read beyond section?\n");
161 /* copy it from temporary buffer to 'buf' according
162 * to address on current objdump line */
163 off = addr - start_addr;
166 written_bytes = MIN(read_bytes, *len - off);
167 memcpy(buf + off, tmp, written_bytes);
168 off_last = off + written_bytes;
171 /* len returns number of bytes that could not be read */
179 static int read_via_objdump(const char *filename, u64 addr, void *buf,
182 char cmd[PATH_MAX * 2];
187 fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s";
188 ret = snprintf(cmd, sizeof(cmd), fmt, test_objdump_path, addr, addr + len,
190 if (ret <= 0 || (size_t)ret >= sizeof(cmd))
193 pr_debug("Objdump command is: %s\n", cmd);
195 /* Ignore objdump errors */
196 strcat(cmd, " 2>/dev/null");
200 pr_debug("popen failed\n");
204 ret = read_objdump_output(f, buf, &len, addr);
206 pr_debug("objdump read too few bytes: %zd\n", len);
216 static void dump_buf(unsigned char *buf, size_t len)
220 for (i = 0; i < len; i++) {
221 pr_debug("0x%02x ", buf[i]);
228 static int read_object_code(u64 addr, size_t len, u8 cpumode,
229 struct thread *thread, struct state *state)
231 struct addr_location al;
232 unsigned char buf1[BUFSZ] = {0};
233 unsigned char buf2[BUFSZ] = {0};
236 const char *objdump_name;
237 char decomp_name[KMOD_DECOMP_LEN];
242 pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
244 addr_location__init(&al);
245 if (!thread__find_map(thread, cpumode, addr, &al) || !map__dso(al.map)) {
246 if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
247 pr_debug("Hypervisor address can not be resolved - skipping\n");
251 pr_debug("thread__find_map failed\n");
255 dso = map__dso(al.map);
256 pr_debug("File is: %s\n", dso->long_name);
258 if (dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(dso)) {
259 pr_debug("Unexpected kernel address - skipping\n");
263 pr_debug("On file address is: %#"PRIx64"\n", al.addr);
268 /* Do not go off the map */
269 if (addr + len > map__end(al.map))
270 len = map__end(al.map) - addr;
273 * Some architectures (ex: powerpc) have stubs (trampolines) in kernel
274 * modules to manage long jumps. Check if the ip offset falls in stubs
275 * sections for kernel modules. And skip module address after text end
277 if (dso->is_kmod && al.addr > dso->text_end) {
278 pr_debug("skipping the module address %#"PRIx64" after text end\n", al.addr);
282 /* Read the object code using perf */
283 ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)),
285 if (ret_len != len) {
286 pr_debug("dso__data_read_offset failed\n");
292 * Converting addresses for use by objdump requires more information.
293 * map__load() does that. See map__rip_2objdump() for details.
295 if (map__load(al.map)) {
300 /* objdump struggles with kcore - try each map only once */
301 if (dso__is_kcore(dso)) {
304 for (d = 0; d < state->done_cnt; d++) {
305 if (state->done[d] == map__start(al.map)) {
306 pr_debug("kcore map tested already");
307 pr_debug(" - skipping\n");
311 if (state->done_cnt >= ARRAY_SIZE(state->done)) {
312 pr_debug("Too many kcore maps - skipping\n");
315 state->done[state->done_cnt++] = map__start(al.map);
318 objdump_name = dso->long_name;
319 if (dso__needs_decompress(dso)) {
320 if (dso__decompress_kmodule_path(dso, objdump_name,
322 sizeof(decomp_name)) < 0) {
323 pr_debug("decompression failed\n");
329 objdump_name = decomp_name;
332 /* Read the object code using objdump */
333 objdump_addr = map__rip_2objdump(al.map, al.addr);
334 ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
337 unlink(objdump_name);
341 * The kernel maps are inaccurate - assume objdump is right in
344 if (cpumode == PERF_RECORD_MISC_KERNEL ||
345 cpumode == PERF_RECORD_MISC_GUEST_KERNEL) {
348 pr_debug("Reducing len to %zu\n", len);
349 } else if (dso__is_kcore(dso)) {
351 * objdump cannot handle very large segments
352 * that may be found in kcore.
354 pr_debug("objdump failed for kcore");
355 pr_debug(" - skipping\n");
363 pr_debug("read_via_objdump failed\n");
368 /* The results should be identical */
369 if (memcmp(buf1, buf2, len)) {
370 pr_debug("Bytes read differ from those read by objdump\n");
371 pr_debug("buf1 (dso):\n");
373 pr_debug("buf2 (objdump):\n");
378 pr_debug("Bytes read match those read by objdump\n");
380 addr_location__exit(&al);
384 static int process_sample_event(struct machine *machine,
385 struct evlist *evlist,
386 union perf_event *event, struct state *state)
388 struct perf_sample sample;
389 struct thread *thread;
392 if (evlist__parse_sample(evlist, event, &sample)) {
393 pr_debug("evlist__parse_sample failed\n");
397 thread = machine__findnew_thread(machine, sample.pid, sample.tid);
399 pr_debug("machine__findnew_thread failed\n");
403 ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state);
408 static int process_event(struct machine *machine, struct evlist *evlist,
409 union perf_event *event, struct state *state)
411 if (event->header.type == PERF_RECORD_SAMPLE)
412 return process_sample_event(machine, evlist, event, state);
414 if (event->header.type == PERF_RECORD_THROTTLE ||
415 event->header.type == PERF_RECORD_UNTHROTTLE)
418 if (event->header.type < PERF_RECORD_MAX) {
421 ret = machine__process_event(machine, event, NULL);
423 pr_debug("machine__process_event failed, event type %u\n",
431 static int process_events(struct machine *machine, struct evlist *evlist,
434 union perf_event *event;
438 for (i = 0; i < evlist->core.nr_mmaps; i++) {
439 md = &evlist->mmap[i];
440 if (perf_mmap__read_init(&md->core) < 0)
443 while ((event = perf_mmap__read_event(&md->core)) != NULL) {
444 ret = process_event(machine, evlist, event, state);
445 perf_mmap__consume(&md->core);
449 perf_mmap__read_done(&md->core);
454 static int comp(const void *a, const void *b)
456 return *(int *)a - *(int *)b;
459 static void do_sort_something(void)
463 for (i = 0; i < (int)ARRAY_SIZE(buf); i++)
464 buf[i] = ARRAY_SIZE(buf) - i - 1;
466 qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp);
468 for (i = 0; i < (int)ARRAY_SIZE(buf); i++) {
470 pr_debug("qsort failed\n");
476 static void sort_something(void)
480 for (i = 0; i < 10; i++)
484 static void syscall_something(void)
489 for (i = 0; i < 1000; i++) {
490 if (pipe(pipefd) < 0) {
491 pr_debug("pipe failed\n");
499 static void fs_something(void)
501 const char *test_file_name = "temp-perf-code-reading-test-file--";
505 for (i = 0; i < 1000; i++) {
506 f = fopen(test_file_name, "w+");
509 unlink(test_file_name);
514 static void do_something(void)
524 TEST_CODE_READING_OK,
525 TEST_CODE_READING_NO_VMLINUX,
526 TEST_CODE_READING_NO_KCORE,
527 TEST_CODE_READING_NO_ACCESS,
528 TEST_CODE_READING_NO_KERNEL_OBJ,
531 static int do_test_code_reading(bool try_kcore)
533 struct machine *machine;
534 struct thread *thread;
535 struct record_opts opts = {
536 .mmap_pages = UINT_MAX,
537 .user_freq = UINT_MAX,
538 .user_interval = ULLONG_MAX,
544 struct state state = {
547 struct perf_thread_map *threads = NULL;
548 struct perf_cpu_map *cpus = NULL;
549 struct evlist *evlist = NULL;
550 struct evsel *evsel = NULL;
554 bool have_vmlinux, have_kcore;
556 const char *events[] = { "cycles", "cycles:u", "cpu-clock", "cpu-clock:u", NULL };
561 machine = machine__new_host();
562 machine->env = &perf_env;
564 ret = machine__create_kernel_maps(machine);
566 pr_debug("machine__create_kernel_maps failed\n");
570 /* Force the use of kallsyms instead of vmlinux to try kcore */
572 symbol_conf.kallsyms_name = "/proc/kallsyms";
574 /* Load kernel map */
575 map = machine__kernel_map(machine);
576 ret = map__load(map);
578 pr_debug("map__load failed\n");
582 have_vmlinux = dso__is_vmlinux(dso);
583 have_kcore = dso__is_kcore(dso);
585 /* 2nd time through we just try kcore */
586 if (try_kcore && !have_kcore)
587 return TEST_CODE_READING_NO_KCORE;
589 /* No point getting kernel events if there is no kernel object */
590 if (!have_vmlinux && !have_kcore)
593 threads = thread_map__new_by_tid(pid);
595 pr_debug("thread_map__new_by_tid failed\n");
599 ret = perf_event__synthesize_thread_map(NULL, threads,
600 perf_event__process, machine,
603 pr_debug("perf_event__synthesize_thread_map failed\n");
607 thread = machine__findnew_thread(machine, pid, pid);
609 pr_debug("machine__findnew_thread failed\n");
613 cpus = perf_cpu_map__new_online_cpus();
615 pr_debug("perf_cpu_map__new failed\n");
619 while (events[evidx]) {
622 evlist = evlist__new();
624 pr_debug("evlist__new failed\n");
628 perf_evlist__set_maps(&evlist->core, cpus, threads);
631 pr_debug("Parsing event '%s'\n", str);
632 ret = parse_event(evlist, str);
634 pr_debug("parse_events failed\n");
638 evlist__config(evlist, &opts, NULL);
640 evsel = evlist__first(evlist);
642 evsel->core.attr.comm = 1;
643 evsel->core.attr.disabled = 1;
644 evsel->core.attr.enable_on_exec = 0;
646 ret = evlist__open(evlist);
650 if (events[evidx] == NULL && verbose > 0) {
652 evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
653 pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
657 * Both cpus and threads are now owned by evlist
658 * and will be freed by following perf_evlist__set_maps
659 * call. Getting reference to keep them alive.
661 perf_cpu_map__get(cpus);
662 perf_thread_map__get(threads);
663 perf_evlist__set_maps(&evlist->core, NULL, NULL);
664 evlist__delete(evlist);
671 if (events[evidx] == NULL)
674 ret = evlist__mmap(evlist, UINT_MAX);
676 pr_debug("evlist__mmap failed\n");
680 evlist__enable(evlist);
684 evlist__disable(evlist);
686 ret = process_events(machine, evlist, &state);
690 if (!have_vmlinux && !have_kcore && !try_kcore)
691 err = TEST_CODE_READING_NO_KERNEL_OBJ;
692 else if (!have_vmlinux && !try_kcore)
693 err = TEST_CODE_READING_NO_VMLINUX;
694 else if (strstr(events[evidx], ":u"))
695 err = TEST_CODE_READING_NO_ACCESS;
697 err = TEST_CODE_READING_OK;
701 evlist__delete(evlist);
702 perf_cpu_map__put(cpus);
703 perf_thread_map__put(threads);
704 machine__delete(machine);
709 static int test__code_reading(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
713 ret = do_test_code_reading(false);
715 ret = do_test_code_reading(true);
718 case TEST_CODE_READING_OK:
720 case TEST_CODE_READING_NO_VMLINUX:
721 pr_debug("no vmlinux\n");
723 case TEST_CODE_READING_NO_KCORE:
724 pr_debug("no kcore\n");
726 case TEST_CODE_READING_NO_ACCESS:
727 pr_debug("no access\n");
729 case TEST_CODE_READING_NO_KERNEL_OBJ:
730 pr_debug("no kernel obj\n");
737 DEFINE_SUITE("Object code reading", code_reading);