1// SPDX-License-Identifier: GPL-2.0
2#include <linux/compiler.h>
3#include <linux/types.h>
4#include <linux/zalloc.h>
5#include <inttypes.h>
6#include <limits.h>
7#include <unistd.h>
8#include "tests.h"
9#include "debug.h"
10#include "machine.h"
11#include "event.h"
12#include "../util/unwind.h"
13#include "perf_regs.h"
14#include "map.h"
15#include "symbol.h"
16#include "thread.h"
17#include "callchain.h"
18#include "util/synthetic-events.h"
19
20#if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__)
21#include "arch-tests.h"
22#endif
23
24/* For bsearch. We try to unwind functions in shared object. */
25#include <stdlib.h>
26
27static int mmap_handler(struct perf_tool *tool __maybe_unused,
28			union perf_event *event,
29			struct perf_sample *sample,
30			struct machine *machine)
31{
32	return machine__process_mmap2_event(machine, event, sample);
33}
34
35static int init_live_machine(struct machine *machine)
36{
37	union perf_event event;
38	pid_t pid = getpid();
39
40	memset(&event, 0, sizeof(event));
41	return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
42						  mmap_handler, machine, true);
43}
44
45/*
46 * We need to keep these functions global, despite the
47 * fact that they are used only locally in this object,
48 * in order to keep them around even if the binary is
49 * stripped. If they are gone, the unwind check for
50 * symbol fails.
51 */
52int test_dwarf_unwind__thread(struct thread *thread);
53int test_dwarf_unwind__compare(void *p1, void *p2);
54int test_dwarf_unwind__krava_3(struct thread *thread);
55int test_dwarf_unwind__krava_2(struct thread *thread);
56int test_dwarf_unwind__krava_1(struct thread *thread);
57
58#define MAX_STACK 8
59
60static int unwind_entry(struct unwind_entry *entry, void *arg)
61{
62	unsigned long *cnt = (unsigned long *) arg;
63	char *symbol = entry->ms.sym ? entry->ms.sym->name : NULL;
64	static const char *funcs[MAX_STACK] = {
65		"test__arch_unwind_sample",
66		"test_dwarf_unwind__thread",
67		"test_dwarf_unwind__compare",
68		"bsearch",
69		"test_dwarf_unwind__krava_3",
70		"test_dwarf_unwind__krava_2",
71		"test_dwarf_unwind__krava_1",
72		"test__dwarf_unwind"
73	};
74	/*
75	 * The funcs[MAX_STACK] array index, based on the
76	 * callchain order setup.
77	 */
78	int idx = callchain_param.order == ORDER_CALLER ?
79		  MAX_STACK - *cnt - 1 : *cnt;
80
81	if (*cnt >= MAX_STACK) {
82		pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
83		return -1;
84	}
85
86	if (!symbol) {
87		pr_debug("failed: got unresolved address 0x%" PRIx64 "\n",
88			 entry->ip);
89		return -1;
90	}
91
92	(*cnt)++;
93	pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n",
94		 symbol, entry->ip, funcs[idx]);
95	return strcmp((const char *) symbol, funcs[idx]);
96}
97
98noinline int test_dwarf_unwind__thread(struct thread *thread)
99{
100	struct perf_sample sample;
101	unsigned long cnt = 0;
102	int err = -1;
103
104	memset(&sample, 0, sizeof(sample));
105
106	if (test__arch_unwind_sample(&sample, thread)) {
107		pr_debug("failed to get unwind sample\n");
108		goto out;
109	}
110
111	err = unwind__get_entries(unwind_entry, &cnt, thread,
112				  &sample, MAX_STACK);
113	if (err)
114		pr_debug("unwind failed\n");
115	else if (cnt != MAX_STACK) {
116		pr_debug("got wrong number of stack entries %lu != %d\n",
117			 cnt, MAX_STACK);
118		err = -1;
119	}
120
121 out:
122	zfree(&sample.user_stack.data);
123	zfree(&sample.user_regs.regs);
124	return err;
125}
126
127static int global_unwind_retval = -INT_MAX;
128
129noinline int test_dwarf_unwind__compare(void *p1, void *p2)
130{
131	/* Any possible value should be 'thread' */
132	struct thread *thread = *(struct thread **)p1;
133
134	if (global_unwind_retval == -INT_MAX) {
135		/* Call unwinder twice for both callchain orders. */
136		callchain_param.order = ORDER_CALLER;
137
138		global_unwind_retval = test_dwarf_unwind__thread(thread);
139		if (!global_unwind_retval) {
140			callchain_param.order = ORDER_CALLEE;
141			global_unwind_retval = test_dwarf_unwind__thread(thread);
142		}
143	}
144
145	return p1 - p2;
146}
147
148noinline int test_dwarf_unwind__krava_3(struct thread *thread)
149{
150	struct thread *array[2] = {thread, thread};
151	void *fp = &bsearch;
152	/*
153	 * make _bsearch a volatile function pointer to
154	 * prevent potential optimization, which may expand
155	 * bsearch and call compare directly from this function,
156	 * instead of libc shared object.
157	 */
158	void *(*volatile _bsearch)(void *, void *, size_t,
159			size_t, int (*)(void *, void *));
160
161	_bsearch = fp;
162	_bsearch(array, &thread, 2, sizeof(struct thread **),
163		 test_dwarf_unwind__compare);
164	return global_unwind_retval;
165}
166
167noinline int test_dwarf_unwind__krava_2(struct thread *thread)
168{
169	return test_dwarf_unwind__krava_3(thread);
170}
171
172noinline int test_dwarf_unwind__krava_1(struct thread *thread)
173{
174	return test_dwarf_unwind__krava_2(thread);
175}
176
177int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused)
178{
179	struct machine *machine;
180	struct thread *thread;
181	int err = -1;
182
183	machine = machine__new_host();
184	if (!machine) {
185		pr_err("Could not get machine\n");
186		return -1;
187	}
188
189	if (machine__create_kernel_maps(machine)) {
190		pr_err("Failed to create kernel maps\n");
191		return -1;
192	}
193
194	callchain_param.record_mode = CALLCHAIN_DWARF;
195	dwarf_callchain_users = true;
196
197	if (init_live_machine(machine)) {
198		pr_err("Could not init machine\n");
199		goto out;
200	}
201
202	if (verbose > 1)
203		machine__fprintf(machine, stderr);
204
205	thread = machine__find_thread(machine, getpid(), getpid());
206	if (!thread) {
207		pr_err("Could not get thread\n");
208		goto out;
209	}
210
211	err = test_dwarf_unwind__krava_1(thread);
212	thread__put(thread);
213
214 out:
215	machine__delete_threads(machine);
216	machine__delete(machine);
217	return err;
218}
219