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