1 files changed, 572 insertions, 0 deletions

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
new file mode 100644
index 000000000000..6fb781d5586c
--- /dev/null
+++ b/tools/perf/tests/code-reading.c
@@ -0,0 +1,572 @@
+#include <sys/types.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <inttypes.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 void read_objdump_line(const char *line, size_t line_len, void **buf,
+                              size_t *len)
+{
+        const char *p;
+        size_t i;
+
+        /* Skip to a colon */
+        p = strchr(line, ':');
+        if (!p)
+                return;
+        i = p + 1 - line;
+
+        /* Read bytes */
+        while (*len) {
+                char c1, c2;
+
+                /* Skip spaces */
+                for (; i < line_len; i++) {
+                        if (!isspace(line[i]))
+                                break;
+                }
+                /* Get 2 hex digits */
+                if (i >= line_len || !isxdigit(line[i]))
+                        break;
+                c1 = line[i++];
+                if (i >= line_len || !isxdigit(line[i]))
+                        break;
+                c2 = line[i++];
+                /* Followed by a space */
+                if (i < line_len && line[i] && !isspace(line[i]))
+                        break;
+                /* Store byte */
+                *(unsigned char *)*buf = (hex(c1) << 4) | hex(c2);
+                *buf += 1;
+                *len -= 1;
+        }
+}
+
+static int read_objdump_output(FILE *f, void **buf, size_t *len)
+{
+        char *line = NULL;
+        size_t line_len;
+        ssize_t ret;
+        int err = 0;
+
+        while (1) {
+                ret = getline(&line, &line_len, f);
+                if (feof(f))
+                        break;
+                if (ret < 0) {
+                        pr_debug("getline failed\n");
+                        err = -1;
+                        break;
+                }
+                read_objdump_line(line, ret, buf, len);
+        }
+
+        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 -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);
+        if (len) {
+                pr_debug("objdump read too few bytes\n");
+                if (!ret)
+                        ret = len;
+        }
+
+        pclose(f);
+
+        return ret;
+}
+
+static int read_object_code(u64 addr, size_t len, u8 cpumode,
+                            struct thread *thread, struct machine *machine,
+                            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, machine, 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, 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, NULL))
+                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");
+                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;
+        u8 cpumode;
+
+        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.pid);
+        if (!thread) {
+                pr_debug("machine__findnew_thread failed\n");
+                return -1;
+        }
+
+        cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
+
+        return read_object_code(sample.ip, READLEN, cpumode, thread, machine,
+                                state);
+}
+
+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_MAX)
+                return machine__process_event(machine, event);
+
+        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);
+                        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 machines machines;
+        struct machine *machine;
+        struct thread *thread;
+        struct perf_record_opts opts = {
+                .mmap_pages          = UINT_MAX,
+                .user_freq           = UINT_MAX,
+                .user_interval       = ULLONG_MAX,
+                .freq                = 4000,
+                .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();
+
+        machines__init(&machines);
+        machine = &machines.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->vmlinux_maps[MAP__FUNCTION];
+        ret = map__load(map, NULL);
+        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);
+        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_err;
+        }
+
+        cpus = cpu_map__new(NULL);
+        if (!cpus) {
+                pr_debug("cpu_map__new failed\n");
+                goto out_err;
+        }
+
+        while (1) {
+                const char *str;
+
+                evlist = perf_evlist__new();
+                if (!evlist) {
+                        pr_debug("perf_evlist__new failed\n");
+                        goto out_err;
+                }
+
+                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);
+                if (ret < 0) {
+                        pr_debug("parse_events failed\n");
+                        goto out_err;
+                }
+
+                perf_evlist__config(evlist, &opts);
+
+                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;
+                                perf_evlist__delete(evlist);
+                                evlist = NULL;
+                                continue;
+                        }
+                        pr_debug("perf_evlist__open failed\n");
+                        goto out_err;
+                }
+                break;
+        }
+
+        ret = perf_evlist__mmap(evlist, UINT_MAX, false);
+        if (ret < 0) {
+                pr_debug("perf_evlist__mmap failed\n");
+                goto out_err;
+        }
+
+        perf_evlist__enable(evlist);
+
+        do_something();
+
+        perf_evlist__disable(evlist);
+
+        ret = process_events(machine, evlist, &state);
+        if (ret < 0)
+                goto out_err;
+
+        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_err:
+        if (evlist) {
+                perf_evlist__munmap(evlist);
+                perf_evlist__close(evlist);
+                perf_evlist__delete(evlist);
+        }
+        if (cpus)
+                cpu_map__delete(cpus);
+        if (threads)
+                thread_map__delete(threads);
+        machines__destroy_kernel_maps(&machines);
+        machine__delete_threads(machine);
+        machines__exit(&machines);
+
+        return err;
+}
+
+int test__code_reading(void)
+{
+        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:
+                fprintf(stderr, " (no vmlinux)");
+                return 0;
+        case TEST_CODE_READING_NO_KCORE:
+                fprintf(stderr, " (no kcore)");
+                return 0;
+        case TEST_CODE_READING_NO_ACCESS:
+                fprintf(stderr, " (no access)");
+                return 0;
+        case TEST_CODE_READING_NO_KERNEL_OBJ:
+                fprintf(stderr, " (no kernel obj)");
+                return 0;
+        default:
+                return -1;
+        };
+}