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