1#include <linux/compiler.h>
  2#include <sys/types.h>
  3#include <unistd.h>
  4#include "tests.h"
  5#include "debug.h"
  6#include "machine.h"
  7#include "event.h"
  8#include "unwind.h"
  9#include "perf_regs.h"
 10#include "map.h"
 11#include "thread.h"
 12
 13static int mmap_handler(struct perf_tool *tool __maybe_unused,
 14			union perf_event *event,
 15			struct perf_sample *sample __maybe_unused,
 16			struct machine *machine)
 17{
 18	return machine__process_mmap_event(machine, event, NULL);
 19}
 20
 21static int init_live_machine(struct machine *machine)
 22{
 23	union perf_event event;
 24	pid_t pid = getpid();
 25
 26	return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
 27						  mmap_handler, machine, true);
 28}
 29
 30#define MAX_STACK 6
 31
 32static int unwind_entry(struct unwind_entry *entry, void *arg)
 33{
 34	unsigned long *cnt = (unsigned long *) arg;
 35	char *symbol = entry->sym ? entry->sym->name : NULL;
 36	static const char *funcs[MAX_STACK] = {
 37		"test__arch_unwind_sample",
 38		"unwind_thread",
 39		"krava_3",
 40		"krava_2",
 41		"krava_1",
 42		"test__dwarf_unwind"
 43	};
 44
 45	if (*cnt >= MAX_STACK) {
 46		pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
 47		return -1;
 48	}
 49
 50	if (!symbol) {
 51		pr_debug("failed: got unresolved address 0x%" PRIx64 "\n",
 52			 entry->ip);
 53		return -1;
 54	}
 55
 56	pr_debug("got: %s 0x%" PRIx64 "\n", symbol, entry->ip);
 57	return strcmp((const char *) symbol, funcs[(*cnt)++]);
 58}
 59
 60__attribute__ ((noinline))
 61static int unwind_thread(struct thread *thread, struct machine *machine)
 62{
 63	struct perf_sample sample;
 64	unsigned long cnt = 0;
 65	int err = -1;
 66
 67	memset(&sample, 0, sizeof(sample));
 68
 69	if (test__arch_unwind_sample(&sample, thread)) {
 70		pr_debug("failed to get unwind sample\n");
 71		goto out;
 72	}
 73
 74	err = unwind__get_entries(unwind_entry, &cnt, machine, thread,
 75				  &sample, MAX_STACK);
 76	if (err)
 77		pr_debug("unwind failed\n");
 78	else if (cnt != MAX_STACK) {
 79		pr_debug("got wrong number of stack entries %lu != %d\n",
 80			 cnt, MAX_STACK);
 81		err = -1;
 82	}
 83
 84 out:
 85	free(sample.user_stack.data);
 86	free(sample.user_regs.regs);
 87	return err;
 88}
 89
 90__attribute__ ((noinline))
 91static int krava_3(struct thread *thread, struct machine *machine)
 92{
 93	return unwind_thread(thread, machine);
 94}
 95
 96__attribute__ ((noinline))
 97static int krava_2(struct thread *thread, struct machine *machine)
 98{
 99	return krava_3(thread, machine);
100}
101
102__attribute__ ((noinline))
103static int krava_1(struct thread *thread, struct machine *machine)
104{
105	return krava_2(thread, machine);
106}
107
108int test__dwarf_unwind(void)
109{
110	struct machines machines;
111	struct machine *machine;
112	struct thread *thread;
113	int err = -1;
114
115	machines__init(&machines);
116
117	machine = machines__find(&machines, HOST_KERNEL_ID);
118	if (!machine) {
119		pr_err("Could not get machine\n");
120		return -1;
121	}
122
123	if (init_live_machine(machine)) {
124		pr_err("Could not init machine\n");
125		goto out;
126	}
127
128	if (verbose > 1)
129		machine__fprintf(machine, stderr);
130
131	thread = machine__find_thread(machine, getpid(), getpid());
132	if (!thread) {
133		pr_err("Could not get thread\n");
134		goto out;
135	}
136
137	err = krava_1(thread, machine);
138
139 out:
140	machine__delete_threads(machine);
141	machine__exit(machine);
142	machines__exit(&machines);
143	return err;
144}