// 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 <perf/cpumap.h>
#include <perf/evlist.h>
#include <perf/mmap.h>
#include "debug.h"
#include "dso.h"
#include "env.h"
#include "parse-events.h"
#include "evlist.h"
#include "evsel.h"
#include "thread_map.h"
#include "machine.h"
#include "map.h"
#include "symbol.h"
#include "event.h"
#include "record.h"
#include "util/mmap.h"
#include "util/string2.h"
#include "util/synthetic-events.h"
#include "util/util.h"
#include "thread.h"
#include "tests.h"
#include <linux/ctype.h>
#define BUFSZ 1024
#define READLEN 128
struct state {
u64 done[1024];
size_t done_cnt;
};
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 && !host_is_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, test_objdump_path, 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] = {0};
unsigned char buf2[BUFSZ] = {0};
size_t ret_len;
u64 objdump_addr;
const char *objdump_name;
char decomp_name[KMOD_DECOMP_LEN];
bool decomp = false;
int ret, err = 0;
struct dso *dso;
pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
addr_location__init(&al);
if (!thread__find_map(thread, cpumode, addr, &al) || !map__dso(al.map)) {
if (cpumode == PERF_RECORD_MISC_HYPERVISOR) {
pr_debug("Hypervisor address can not be resolved - skipping\n");
goto out;
}
pr_debug("thread__find_map failed\n");
err = -1;
goto out;
}
dso = map__dso(al.map);
pr_debug("File is: %s\n", dso__long_name(dso));
if (dso__symtab_type(dso) == DSO_BINARY_TYPE__KALLSYMS && !dso__is_kcore(dso)) {
pr_debug("Unexpected kernel address - skipping\n");
goto out;
}
pr_debug("On file address is: %#"PRIx64"\n", al.addr);
if (len > BUFSZ)
len = BUFSZ;
/* Do not go off the map */
if (addr + len > map__end(al.map))
len = map__end(al.map) - addr;
/*
* Some architectures (ex: powerpc) have stubs (trampolines) in kernel
* modules to manage long jumps. Check if the ip offset falls in stubs
* sections for kernel modules. And skip module address after text end
*/
if (dso__is_kmod(dso) && al.addr > dso__text_end(dso)) {
pr_debug("skipping the module address %#"PRIx64" after text end\n", al.addr);
goto out;
}
/* Read the object code using perf */
ret_len = dso__data_read_offset(dso, maps__machine(thread__maps(thread)),
al.addr, buf1, len);
if (ret_len != len) {
pr_debug("dso__data_read_offset failed\n");
err = -1;
goto out;
}
/*
* Converting addresses for use by objdump requires more information.
* map__load() does that. See map__rip_2objdump() for details.
*/
if (map__load(al.map)) {
err = -1;
goto out;
}
/* objdump struggles with kcore - try each map only once */
if (dso__is_kcore(dso)) {
size_t d;
for (d = 0; d < state->done_cnt; d++) {
if (state->done[d] == map__start(al.map)) {
pr_debug("kcore map tested already");
pr_debug(" - skipping\n");
goto out;
}
}
if (state->done_cnt >= ARRAY_SIZE(state->done)) {
pr_debug("Too many kcore maps - skipping\n");
goto out;
}
state->done[state->done_cnt++] = map__start(al.map);
}
objdump_name = dso__long_name(dso);
if (dso__needs_decompress(dso)) {
if (dso__decompress_kmodule_path(dso, objdump_name,
decomp_name,
sizeof(decomp_name)) < 0) {
pr_debug("decompression failed\n");
err = -1;
goto out;
}
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(dso)) {
/*
* objdump cannot handle very large segments
* that may be found in kcore.
*/
pr_debug("objdump failed for kcore");
pr_debug(" - skipping\n");
} else {
err = -1;
}
goto out;
}
}
if (ret < 0) {
pr_debug("read_via_objdump failed\n");
err = -1;
goto out;
}
/* 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);
err = -1;
goto out;
}
pr_debug("Bytes read match those read by objdump\n");
out:
addr_location__exit(&al);
return err;
}
static int process_sample_event(struct machine *machine,
struct evlist *evlist,
union perf_event *event, struct state *state)
{
struct perf_sample sample;
struct thread *thread;
int ret;
if (evlist__parse_sample(evlist, event, &sample)) {
pr_debug("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 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 evlist *evlist,
struct state *state)
{
union perf_event *event;
struct mmap *md;
int i, ret;
for (i = 0; i < evlist->core.nr_mmaps; i++) {
md = &evlist->mmap[i];
if (perf_mmap__read_init(&md->core) < 0)
continue;
while ((event = perf_mmap__read_event(&md->core)) != NULL) {
ret = process_event(machine, evlist, event, state);
perf_mmap__consume(&md->core);
if (ret < 0)
return ret;
}
perf_mmap__read_done(&md->core);
}
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 perf_thread_map *threads = NULL;
struct perf_cpu_map *cpus = NULL;
struct evlist *evlist = NULL;
struct evsel *evsel = NULL;
int err = -1, ret;
pid_t pid;
struct map *map;
bool have_vmlinux, have_kcore;
struct dso *dso;
const char *events[] = { "cycles", "cycles:u", "cpu-clock", "cpu-clock:u", NULL };
int evidx = 0;
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;
}
dso = map__dso(map);
have_vmlinux = dso__is_vmlinux(dso);
have_kcore = dso__is_kcore(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)
evidx++;
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,
true, false);
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 = perf_cpu_map__new_online_cpus();
if (!cpus) {
pr_debug("perf_cpu_map__new failed\n");
goto out_put;
}
while (events[evidx]) {
const char *str;
evlist = evlist__new();
if (!evlist) {
pr_debug("evlist__new failed\n");
goto out_put;
}
perf_evlist__set_maps(&evlist->core, cpus, threads);
str = events[evidx];
pr_debug("Parsing event '%s'\n", str);
ret = parse_event(evlist, str);
if (ret < 0) {
pr_debug("parse_events failed\n");
goto out_put;
}
evlist__config(evlist, &opts, NULL);
evlist__for_each_entry(evlist, evsel) {
evsel->core.attr.comm = 1;
evsel->core.attr.disabled = 1;
evsel->core.attr.enable_on_exec = 0;
}
ret = evlist__open(evlist);
if (ret < 0) {
evidx++;
if (events[evidx] == NULL && verbose > 0) {
char errbuf[512];
evlist__strerror_open(evlist, errno, errbuf, sizeof(errbuf));
pr_debug("perf_evlist__open() failed!\n%s\n", errbuf);
}
/*
* Both cpus and threads are now owned by evlist
* and will be freed by following perf_evlist__set_maps
* call. Getting reference to keep them alive.
*/
perf_cpu_map__get(cpus);
perf_thread_map__get(threads);
perf_evlist__set_maps(&evlist->core, NULL, NULL);
evlist__delete(evlist);
evlist = NULL;
continue;
}
break;
}
if (events[evidx] == NULL)
goto out_put;
ret = evlist__mmap(evlist, UINT_MAX);
if (ret < 0) {
pr_debug("evlist__mmap failed\n");
goto out_put;
}
evlist__enable(evlist);
do_something();
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 (strstr(events[evidx], ":u"))
err = TEST_CODE_READING_NO_ACCESS;
else
err = TEST_CODE_READING_OK;
out_put:
thread__put(thread);
out_err:
evlist__delete(evlist);
perf_cpu_map__put(cpus);
perf_thread_map__put(threads);
machine__delete(machine);
return err;
}
static int test__code_reading(struct test_suite *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;
};
}
DEFINE_SUITE("Object code reading", code_reading);
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