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#include <linux/compiler.h>
#include <linux/types.h>
#include <unistd.h>
#include "tests.h"
#include "debug.h"
#include "machine.h"
#include "event.h"
#include "unwind.h"
#include "perf_regs.h"
#include "map.h"
#include "thread.h"
#include "callchain.h"
/* For bsearch. We try to unwind functions in shared object. */
#include <stdlib.h>
static int mmap_handler(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample __maybe_unused,
struct machine *machine)
{
return machine__process_mmap2_event(machine, event, NULL);
}
static int init_live_machine(struct machine *machine)
{
union perf_event event;
pid_t pid = getpid();
return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
mmap_handler, machine, true);
}
#define MAX_STACK 8
static int unwind_entry(struct unwind_entry *entry, void *arg)
{
unsigned long *cnt = (unsigned long *) arg;
char *symbol = entry->sym ? entry->sym->name : NULL;
static const char *funcs[MAX_STACK] = {
"test__arch_unwind_sample",
"unwind_thread",
"compare",
"bsearch",
"krava_3",
"krava_2",
"krava_1",
"test__dwarf_unwind"
};
if (*cnt >= MAX_STACK) {
pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
return -1;
}
if (!symbol) {
pr_debug("failed: got unresolved address 0x%" PRIx64 "\n",
entry->ip);
return -1;
}
pr_debug("got: %s 0x%" PRIx64 "\n", symbol, entry->ip);
return strcmp((const char *) symbol, funcs[(*cnt)++]);
}
__attribute__ ((noinline))
static int unwind_thread(struct thread *thread)
{
struct perf_sample sample;
unsigned long cnt = 0;
int err = -1;
memset(&sample, 0, sizeof(sample));
if (test__arch_unwind_sample(&sample, thread)) {
pr_debug("failed to get unwind sample\n");
goto out;
}
err = unwind__get_entries(unwind_entry, &cnt, thread,
&sample, MAX_STACK);
if (err)
pr_debug("unwind failed\n");
else if (cnt != MAX_STACK) {
pr_debug("got wrong number of stack entries %lu != %d\n",
cnt, MAX_STACK);
err = -1;
}
out:
free(sample.user_stack.data);
free(sample.user_regs.regs);
return err;
}
static int global_unwind_retval = -INT_MAX;
__attribute__ ((noinline))
static int compare(void *p1, void *p2)
{
/* Any possible value should be 'thread' */
struct thread *thread = *(struct thread **)p1;
if (global_unwind_retval == -INT_MAX)
global_unwind_retval = unwind_thread(thread);
return p1 - p2;
}
__attribute__ ((noinline))
static int krava_3(struct thread *thread)
{
struct thread *array[2] = {thread, thread};
void *fp = &bsearch;
/*
* make _bsearch a volatile function pointer to
* prevent potential optimization, which may expand
* bsearch and call compare directly from this function,
* instead of libc shared object.
*/
void *(*volatile _bsearch)(void *, void *, size_t,
size_t, int (*)(void *, void *));
_bsearch = fp;
_bsearch(array, &thread, 2, sizeof(struct thread **), compare);
return global_unwind_retval;
}
__attribute__ ((noinline))
static int krava_2(struct thread *thread)
{
return krava_3(thread);
}
__attribute__ ((noinline))
static int krava_1(struct thread *thread)
{
return krava_2(thread);
}
int test__dwarf_unwind(void)
{
struct machines machines;
struct machine *machine;
struct thread *thread;
int err = -1;
machines__init(&machines);
machine = machines__find(&machines, HOST_KERNEL_ID);
if (!machine) {
pr_err("Could not get machine\n");
return -1;
}
callchain_param.record_mode = CALLCHAIN_DWARF;
if (init_live_machine(machine)) {
pr_err("Could not init machine\n");
goto out;
}
if (verbose > 1)
machine__fprintf(machine, stderr);
thread = machine__find_thread(machine, getpid(), getpid());
if (!thread) {
pr_err("Could not get thread\n");
goto out;
}
err = krava_1(thread);
out:
machine__delete_threads(machine);
machine__exit(machine);
machines__exit(&machines);
return err;
}
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