#include <linux/types.h> #include <stdlib.h> #include <unistd.h> #include <stdio.h> #include <ctype.h> #include <string.h> #include "parse-events.h" #include "evlist.h" #include "evsel.h" #include "thread_map.h" #include "cpumap.h" #include "machine.h" #include "event.h" #include "thread.h" #include "tests.h" #define BUFSZ 1024 #define READLEN 128 struct state { u64 done[1024]; size_t done_cnt; }; static unsigned int hex(char c) { if (c >= '0' && c <= '9') return c - '0'; if (c >= 'a' && c <= 'f') return c - 'a' + 10; return c - 'A' + 10; } static size_t read_objdump_chunk(const char **line, unsigned char **buf, size_t *buf_len) { size_t bytes_read = 0; unsigned char *chunk_start = *buf; /* Read bytes */ while (*buf_len > 0) { char c1, c2; /* Get 2 hex digits */ c1 = *(*line)++; if (!isxdigit(c1)) break; c2 = *(*line)++; if (!isxdigit(c2)) break; /* Store byte and advance buf */ **buf = (hex(c1) << 4) | hex(c2); (*buf)++; (*buf_len)--; bytes_read++; /* End of chunk? */ if (isspace(**line)) break; } /* * objdump will display raw insn as LE if code endian * is LE and bytes_per_chunk > 1. In that case reverse * the chunk we just read. * * see disassemble_bytes() at binutils/objdump.c for details * how objdump chooses display endian) */ if (bytes_read > 1 && !bigendian()) { unsigned char *chunk_end = chunk_start + bytes_read - 1; unsigned char tmp; while (chunk_start < chunk_end) { tmp = *chunk_start; *chunk_start = *chunk_end; *chunk_end = tmp; chunk_start++; chunk_end--; } } return bytes_read; } static size_t read_objdump_line(const char *line, unsigned char *buf, size_t buf_len) { const char *p; size_t ret, bytes_read = 0; /* Skip to a colon */ p = strchr(line, ':'); if (!p) return 0; p++; /* Skip initial spaces */ while (*p) { if (!isspace(*p)) break; p++; } do { ret = read_objdump_chunk(&p, &buf, &buf_len); bytes_read += ret; p++; } while (ret > 0); /* return number of successfully read bytes */ return bytes_read; } static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr) { char *line = NULL; size_t line_len, off_last = 0; ssize_t ret; int err = 0; u64 addr, last_addr = start_addr; while (off_last < *len) { size_t off, read_bytes, written_bytes; unsigned char tmp[BUFSZ]; ret = getline(&line, &line_len, f); if (feof(f)) break; if (ret < 0) { pr_debug("getline failed\n"); err = -1; break; } /* read objdump data into temporary buffer */ read_bytes = read_objdump_line(line, tmp, sizeof(tmp)); if (!read_bytes) continue; if (sscanf(line, "%"PRIx64, &addr) != 1) continue; if (addr < last_addr) { pr_debug("addr going backwards, read beyond section?\n"); break; } last_addr = addr; /* copy it from temporary buffer to 'buf' according * to address on current objdump line */ off = addr - start_addr; if (off >= *len) break; written_bytes = MIN(read_bytes, *len - off); memcpy(buf + off, tmp, written_bytes); off_last = off + written_bytes; } /* len returns number of bytes that could not be read */ *len -= off_last; free(line); return err; } static int read_via_objdump(const char *filename, u64 addr, void *buf, size_t len) { char cmd[PATH_MAX * 2]; const char *fmt; FILE *f; int ret; fmt = "%s -z -d --start-address=0x%"PRIx64" --stop-address=0x%"PRIx64" %s"; ret = snprintf(cmd, sizeof(cmd), fmt, "objdump", addr, addr + len, filename); if (ret <= 0 || (size_t)ret >= sizeof(cmd)) return -1; pr_debug("Objdump command is: %s\n", cmd); /* Ignore objdump errors */ strcat(cmd, " 2>/dev/null"); f = popen(cmd, "r"); if (!f) { pr_debug("popen failed\n"); return -1; } ret = read_objdump_output(f, buf, &len, addr); if (len) { pr_debug("objdump read too few bytes: %zd\n", len); if (!ret) ret = len; } pclose(f); return ret; } static void dump_buf(unsigned char *buf, size_t len) { size_t i; for (i = 0; i < len; i++) { pr_debug("0x%02x ", buf[i]); if (i % 16 == 15) pr_debug("\n"); } pr_debug("\n"); } static int read_object_code(u64 addr, size_t len, u8 cpumode, struct thread *thread, struct state *state) { struct addr_location al; unsigned char buf1[BUFSZ]; unsigned char buf2[BUFSZ]; size_t ret_len; u64 objdump_addr; int ret; pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr); thread__find_addr_map(thread, cpumode, MAP__FUNCTION, addr, &al); if (!al.map || !al.map->dso) { pr_debug("thread__find_addr_map failed\n"); return -1; } pr_debug("File is: %s\n", al.map->dso->long_name); if (al.map->dso->symtab_type == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(al.map->dso)) { pr_debug("Unexpected kernel address - skipping\n"); return 0; } pr_debug("On file address is: %#"PRIx64"\n", al.addr); if (len > BUFSZ) len = BUFSZ; /* Do not go off the map */ if (addr + len > al.map->end) len = al.map->end - addr; /* Read the object code using perf */ ret_len = dso__data_read_offset(al.map->dso, thread->mg->machine, al.addr, buf1, len); if (ret_len != len) { pr_debug("dso__data_read_offset failed\n"); return -1; } /* * Converting addresses for use by objdump requires more information. * map__load() does that. See map__rip_2objdump() for details. */ if (map__load(al.map)) return -1; /* objdump struggles with kcore - try each map only once */ if (dso__is_kcore(al.map->dso)) { size_t d; for (d = 0; d < state->done_cnt; d++) { if (state->done[d] == al.map->start) { pr_debug("kcore map tested already"); pr_debug(" - skipping\n"); return 0; } } if (state->done_cnt >= ARRAY_SIZE(state->done)) { pr_debug("Too many kcore maps - skipping\n"); return 0; } state->done[state->done_cnt++] = al.map->start; } /* Read the object code using objdump */ objdump_addr = map__rip_2objdump(al.map, al.addr); ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len); if (ret > 0) { /* * The kernel maps are inaccurate - assume objdump is right in * that case. */ if (cpumode == PERF_RECORD_MISC_KERNEL || cpumode == PERF_RECORD_MISC_GUEST_KERNEL) { len -= ret; if (len) { pr_debug("Reducing len to %zu\n", len); } else if (dso__is_kcore(al.map->dso)) { /* * objdump cannot handle very large segments * that may be found in kcore. */ pr_debug("objdump failed for kcore"); pr_debug(" - skipping\n"); return 0; } else { return -1; } } } if (ret < 0) { pr_debug("read_via_objdump failed\n"); return -1; } /* The results should be identical */ if (memcmp(buf1, buf2, len)) { pr_debug("Bytes read differ from those read by objdump\n"); pr_debug("buf1 (dso):\n"); dump_buf(buf1, len); pr_debug("buf2 (objdump):\n"); dump_buf(buf2, len); return -1; } pr_debug("Bytes read match those read by objdump\n"); return 0; } static int process_sample_event(struct machine *machine, struct perf_evlist *evlist, union perf_event *event, struct state *state) { struct perf_sample sample; struct thread *thread; int ret; if (perf_evlist__parse_sample(evlist, event, &sample)) { pr_debug("perf_evlist__parse_sample failed\n"); return -1; } thread = machine__findnew_thread(machine, sample.pid, sample.tid); if (!thread) { pr_debug("machine__findnew_thread failed\n"); return -1; } ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); thread__put(thread); return ret; } static int process_event(struct machine *machine, struct perf_evlist *evlist, union perf_event *event, struct state *state) { if (event->header.type == PERF_RECORD_SAMPLE) return process_sample_event(machine, evlist, event, state); if (event->header.type == PERF_RECORD_THROTTLE || event->header.type == PERF_RECORD_UNTHROTTLE) return 0; if (event->header.type < PERF_RECORD_MAX) { int ret; ret = machine__process_event(machine, event, NULL); if (ret < 0) pr_debug("machine__process_event failed, event type %u\n", event->header.type); return ret; } return 0; } static int process_events(struct machine *machine, struct perf_evlist *evlist, struct state *state) { union perf_event *event; int i, ret; for (i = 0; i < evlist->nr_mmaps; i++) { while ((event = perf_evlist__mmap_read(evlist, i)) != NULL) { ret = process_event(machine, evlist, event, state); perf_evlist__mmap_consume(evlist, i); if (ret < 0) return ret; } } return 0; } static int comp(const void *a, const void *b) { return *(int *)a - *(int *)b; } static void do_sort_something(void) { int buf[40960], i; for (i = 0; i < (int)ARRAY_SIZE(buf); i++) buf[i] = ARRAY_SIZE(buf) - i - 1; qsort(buf, ARRAY_SIZE(buf), sizeof(int), comp); for (i = 0; i < (int)ARRAY_SIZE(buf); i++) { if (buf[i] != i) { pr_debug("qsort failed\n"); break; } } } static void sort_something(void) { int i; for (i = 0; i < 10; i++) do_sort_something(); } static void syscall_something(void) { int pipefd[2]; int i; for (i = 0; i < 1000; i++) { if (pipe(pipefd) < 0) { pr_debug("pipe failed\n"); break; } close(pipefd[1]); close(pipefd[0]); } } static void fs_something(void) { const char *test_file_name = "temp-perf-code-reading-test-file--"; FILE *f; int i; for (i = 0; i < 1000; i++) { f = fopen(test_file_name, "w+"); if (f) { fclose(f); unlink(test_file_name); } } } static void do_something(void) { fs_something(); sort_something(); syscall_something(); } enum { TEST_CODE_READING_OK, TEST_CODE_READING_NO_VMLINUX, TEST_CODE_READING_NO_KCORE, TEST_CODE_READING_NO_ACCESS, TEST_CODE_READING_NO_KERNEL_OBJ, }; static int do_test_code_reading(bool try_kcore) { struct machine *machine; struct thread *thread; struct record_opts opts = { .mmap_pages = UINT_MAX, .user_freq = UINT_MAX, .user_interval = ULLONG_MAX, .freq = 500, .target = { .uses_mmap = true, }, }; struct state state = { .done_cnt = 0, }; struct thread_map *threads = NULL; struct cpu_map *cpus = NULL; struct perf_evlist *evlist = NULL; struct perf_evsel *evsel = NULL; int err = -1, ret; pid_t pid; struct map *map; bool have_vmlinux, have_kcore, excl_kernel = false; pid = getpid(); machine = machine__new_host(); ret = machine__create_kernel_maps(machine); if (ret < 0) { pr_debug("machine__create_kernel_maps failed\n"); goto out_err; } /* Force the use of kallsyms instead of vmlinux to try kcore */ if (try_kcore) symbol_conf.kallsyms_name = "/proc/kallsyms"; /* Load kernel map */ map = machine__kernel_map(machine); ret = map__load(map); if (ret < 0) { pr_debug("map__load failed\n"); goto out_err; } have_vmlinux = dso__is_vmlinux(map->dso); have_kcore = dso__is_kcore(map->dso); /* 2nd time through we just try kcore */ if (try_kcore && !have_kcore) return TEST_CODE_READING_NO_KCORE; /* No point getting kernel events if there is no kernel object */ if (!have_vmlinux && !have_kcore) excl_kernel = true; threads = thread_map__new_by_tid(pid); if (!threads) { pr_debug("thread_map__new_by_tid failed\n"); goto out_err; } ret = perf_event__synthesize_thread_map(NULL, threads, perf_event__process, machine, false, 500); if (ret < 0) { pr_debug("perf_event__synthesize_thread_map failed\n"); goto out_err; } thread = machine__findnew_thread(machine, pid, pid); if (!thread) { pr_debug("machine__findnew_thread failed\n"); goto out_put; } cpus = cpu_map__new(NULL); if (!cpus) { pr_debug("cpu_map__new failed\n"); goto out_put; } while (1) { const char *str; evlist = perf_evlist__new(); if (!evlist) { pr_debug("perf_evlist__new failed\n"); goto out_put; } perf_evlist__set_maps(evlist, cpus, threads); if (excl_kernel) str = "cycles:u"; else str = "cycles"; pr_debug("Parsing event '%s'\n", str); ret = parse_events(evlist, str, NULL); if (ret < 0) { pr_debug("parse_events failed\n"); goto out_put; } perf_evlist__config(evlist, &opts, NULL); evsel = perf_evlist__first(evlist); evsel->attr.comm = 1; evsel->attr.disabled = 1; evsel->attr.enable_on_exec = 0; ret = perf_evlist__open(evlist); if (ret < 0) { if (!excl_kernel) { excl_kernel = true; /* * Both cpus and threads are now owned by evlist * and will be freed by following perf_evlist__set_maps * call. Getting refference to keep them alive. */ cpu_map__get(cpus); thread_map__get(threads); perf_evlist__set_maps(evlist, NULL, NULL); perf_evlist__delete(evlist); evlist = NULL; continue; } if (verbose) { char errbuf[512]; perf_evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf)); pr_debug("perf_evlist__open() failed!\n%s\n", errbuf); } goto out_put; } break; } ret = perf_evlist__mmap(evlist, UINT_MAX, false); if (ret < 0) { pr_debug("perf_evlist__mmap failed\n"); goto out_put; } perf_evlist__enable(evlist); do_something(); perf_evlist__disable(evlist); ret = process_events(machine, evlist, &state); if (ret < 0) goto out_put; if (!have_vmlinux && !have_kcore && !try_kcore) err = TEST_CODE_READING_NO_KERNEL_OBJ; else if (!have_vmlinux && !try_kcore) err = TEST_CODE_READING_NO_VMLINUX; else if (excl_kernel) err = TEST_CODE_READING_NO_ACCESS; else err = TEST_CODE_READING_OK; out_put: thread__put(thread); out_err: if (evlist) { perf_evlist__delete(evlist); } else { cpu_map__put(cpus); thread_map__put(threads); } machine__delete_threads(machine); machine__delete(machine); return err; } int test__code_reading(int subtest __maybe_unused) { int ret; ret = do_test_code_reading(false); if (!ret) ret = do_test_code_reading(true); switch (ret) { case TEST_CODE_READING_OK: return 0; case TEST_CODE_READING_NO_VMLINUX: pr_debug("no vmlinux\n"); return 0; case TEST_CODE_READING_NO_KCORE: pr_debug("no kcore\n"); return 0; case TEST_CODE_READING_NO_ACCESS: pr_debug("no access\n"); return 0; case TEST_CODE_READING_NO_KERNEL_OBJ: pr_debug("no kernel obj\n"); return 0; default: return -1; }; }