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-rw-r--r--tools/perf/tests/code-reading.c741
1 files changed, 741 insertions, 0 deletions
diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
new file mode 100644
index 000000000..6b049f3f5
--- /dev/null
+++ b/tools/perf/tests/code-reading.c
@@ -0,0 +1,741 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <errno.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <inttypes.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/param.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"
+
+#include "sane_ctype.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;
+ const char *objdump_name;
+ char decomp_name[KMOD_DECOMP_LEN];
+ bool decomp = false;
+ int ret;
+
+ pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
+
+ if (!thread__find_map(thread, cpumode, addr, &al) || !al.map->dso) {
+ if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
+ pr_debug("Hypervisor address can not be resolved - skipping\n");
+ return 0;
+ }
+
+ pr_debug("thread__find_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;
+ }
+
+ objdump_name = al.map->dso->long_name;
+ if (dso__needs_decompress(al.map->dso)) {
+ if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
+ decomp_name,
+ sizeof(decomp_name)) < 0) {
+ pr_debug("decompression failed\n");
+ return -1;
+ }
+
+ decomp = true;
+ objdump_name = decomp_name;
+ }
+
+ /* Read the object code using objdump */
+ objdump_addr = map__rip_2objdump(al.map, al.addr);
+ ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
+
+ if (decomp)
+ unlink(objdump_name);
+
+ 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;
+ struct perf_mmap *md;
+ int i, ret;
+
+ for (i = 0; i < evlist->nr_mmaps; i++) {
+ md = &evlist->mmap[i];
+ if (perf_mmap__read_init(md) < 0)
+ continue;
+
+ while ((event = perf_mmap__read_event(md)) != NULL) {
+ ret = process_event(machine, evlist, event, state);
+ perf_mmap__consume(md);
+ if (ret < 0)
+ return ret;
+ }
+ perf_mmap__read_done(md);
+ }
+ 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 const char *do_determine_event(bool excl_kernel)
+{
+ const char *event = excl_kernel ? "cycles:u" : "cycles";
+
+#ifdef __s390x__
+ char cpuid[128], model[16], model_c[16], cpum_cf_v[16];
+ unsigned int family;
+ int ret, cpum_cf_a;
+
+ if (get_cpuid(cpuid, sizeof(cpuid)))
+ goto out_clocks;
+ ret = sscanf(cpuid, "%*[^,],%u,%[^,],%[^,],%[^,],%x", &family, model_c,
+ model, cpum_cf_v, &cpum_cf_a);
+ if (ret != 5) /* Not available */
+ goto out_clocks;
+ if (excl_kernel && (cpum_cf_a & 4))
+ return event;
+ if (!excl_kernel && (cpum_cf_a & 2))
+ return event;
+
+ /* Fall through: missing authorization */
+out_clocks:
+ event = excl_kernel ? "cpu-clock:u" : "cpu-clock";
+
+#endif
+ return event;
+}
+
+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();
+ machine->env = &perf_env;
+
+ 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);
+
+ str = do_determine_event(excl_kernel);
+ 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 > 0) {
+ 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);
+ 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(struct test *test __maybe_unused, 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;
+ };
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-24 11:51:43 +0000