int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine)
{
size_t size;
const char *mmap_name;
char name_buff[PATH_MAX];
struct map *map = machine__kernel_map(machine);
struct kmap *kmap;
int err;
union perf_event *event;
if (symbol_conf.kptr_restrict)
return -1;
if (map == NULL)
return -1;
/*
* We should get this from /sys/kernel/sections/.text, but till that is
* available use this, and after it is use this as a fallback for older
* kernels.
*/
event = zalloc((sizeof(event->mmap) + machine->id_hdr_size));
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
return -1;
}
mmap_name = machine__mmap_name(machine, name_buff, sizeof(name_buff));
if (machine__is_host(machine)) {
/*
* kernel uses PERF_RECORD_MISC_USER for user space maps,
* see kernel/perf_event.c __perf_event_mmap
*/
event->header.misc = PERF_RECORD_MISC_KERNEL;
} else {
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
}
kmap = map__kmap(map);
size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
"%s%s", mmap_name, kmap->ref_reloc_sym->name) + 1;
size = PERF_ALIGN(size, sizeof(u64));
event->mmap.header.type = PERF_RECORD_MMAP;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
event->mmap.pgoff = kmap->ref_reloc_sym->addr;
event->mmap.start = map->start;
event->mmap.len = map->end - event->mmap.start;
event->mmap.pid = machine->pid;
err = perf_tool__process_synth_event(tool, event, machine, process);
free(event);
return err;
}
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;
};
}