struct symbol *map__find_symbol_by_name(struct map *map, const char *name,
symbol_filter_t filter)
{
if (map__load(map, filter) < 0)
return NULL;
if (!dso__sorted_by_name(map->dso, map->type))
dso__sort_by_name(map->dso, map->type);
return dso__find_symbol_by_name(map->dso, map->type, name);
}
static int do_test_code_reading(bool try_kcore)
{
struct machines machines;
struct machine *machine;
struct thread *thread;
struct 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, 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_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__set_maps(evlist, NULL, NULL);
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__delete(evlist);
} else {
cpu_map__delete(cpus);
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;
};
}
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 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, 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, 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);
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;
};
}
