GNU Linux-libre 4.19.211-gnu1
[releases.git] / tools / perf / tests / dwarf-unwind.c
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/compiler.h>
3 #include <linux/types.h>
4 #include <inttypes.h>
5 #include <unistd.h>
6 #include "tests.h"
7 #include "debug.h"
8 #include "machine.h"
9 #include "event.h"
10 #include "../util/unwind.h"
11 #include "perf_regs.h"
12 #include "map.h"
13 #include "thread.h"
14 #include "callchain.h"
15
16 #if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__)
17 #include "arch-tests.h"
18 #endif
19
20 /* For bsearch. We try to unwind functions in shared object. */
21 #include <stdlib.h>
22
23 static int mmap_handler(struct perf_tool *tool __maybe_unused,
24                         union perf_event *event,
25                         struct perf_sample *sample,
26                         struct machine *machine)
27 {
28         return machine__process_mmap2_event(machine, event, sample);
29 }
30
31 static int init_live_machine(struct machine *machine)
32 {
33         union perf_event event;
34         pid_t pid = getpid();
35
36         return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
37                                                   mmap_handler, machine, true, 500);
38 }
39
40 /*
41  * We need to keep these functions global, despite the
42  * fact that they are used only locally in this object,
43  * in order to keep them around even if the binary is
44  * stripped. If they are gone, the unwind check for
45  * symbol fails.
46  */
47 int test_dwarf_unwind__thread(struct thread *thread);
48 int test_dwarf_unwind__compare(void *p1, void *p2);
49 int test_dwarf_unwind__krava_3(struct thread *thread);
50 int test_dwarf_unwind__krava_2(struct thread *thread);
51 int test_dwarf_unwind__krava_1(struct thread *thread);
52
53 #define MAX_STACK 8
54
55 static int unwind_entry(struct unwind_entry *entry, void *arg)
56 {
57         unsigned long *cnt = (unsigned long *) arg;
58         char *symbol = entry->sym ? entry->sym->name : NULL;
59         static const char *funcs[MAX_STACK] = {
60                 "test__arch_unwind_sample",
61                 "test_dwarf_unwind__thread",
62                 "test_dwarf_unwind__compare",
63                 "bsearch",
64                 "test_dwarf_unwind__krava_3",
65                 "test_dwarf_unwind__krava_2",
66                 "test_dwarf_unwind__krava_1",
67                 "test__dwarf_unwind"
68         };
69         /*
70          * The funcs[MAX_STACK] array index, based on the
71          * callchain order setup.
72          */
73         int idx = callchain_param.order == ORDER_CALLER ?
74                   MAX_STACK - *cnt - 1 : *cnt;
75
76         if (*cnt >= MAX_STACK) {
77                 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
78                 return -1;
79         }
80
81         if (!symbol) {
82                 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n",
83                          entry->ip);
84                 return -1;
85         }
86
87         (*cnt)++;
88         pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n",
89                  symbol, entry->ip, funcs[idx]);
90         return strcmp((const char *) symbol, funcs[idx]);
91 }
92
93 noinline int test_dwarf_unwind__thread(struct thread *thread)
94 {
95         struct perf_sample sample;
96         unsigned long cnt = 0;
97         int err = -1;
98
99         memset(&sample, 0, sizeof(sample));
100
101         if (test__arch_unwind_sample(&sample, thread)) {
102                 pr_debug("failed to get unwind sample\n");
103                 goto out;
104         }
105
106         err = unwind__get_entries(unwind_entry, &cnt, thread,
107                                   &sample, MAX_STACK);
108         if (err)
109                 pr_debug("unwind failed\n");
110         else if (cnt != MAX_STACK) {
111                 pr_debug("got wrong number of stack entries %lu != %d\n",
112                          cnt, MAX_STACK);
113                 err = -1;
114         }
115
116  out:
117         free(sample.user_stack.data);
118         free(sample.user_regs.regs);
119         return err;
120 }
121
122 static int global_unwind_retval = -INT_MAX;
123
124 noinline int test_dwarf_unwind__compare(void *p1, void *p2)
125 {
126         /* Any possible value should be 'thread' */
127         struct thread *thread = *(struct thread **)p1;
128
129         if (global_unwind_retval == -INT_MAX) {
130                 /* Call unwinder twice for both callchain orders. */
131                 callchain_param.order = ORDER_CALLER;
132
133                 global_unwind_retval = test_dwarf_unwind__thread(thread);
134                 if (!global_unwind_retval) {
135                         callchain_param.order = ORDER_CALLEE;
136                         global_unwind_retval = test_dwarf_unwind__thread(thread);
137                 }
138         }
139
140         return p1 - p2;
141 }
142
143 noinline int test_dwarf_unwind__krava_3(struct thread *thread)
144 {
145         struct thread *array[2] = {thread, thread};
146         void *fp = &bsearch;
147         /*
148          * make _bsearch a volatile function pointer to
149          * prevent potential optimization, which may expand
150          * bsearch and call compare directly from this function,
151          * instead of libc shared object.
152          */
153         void *(*volatile _bsearch)(void *, void *, size_t,
154                         size_t, int (*)(void *, void *));
155
156         _bsearch = fp;
157         _bsearch(array, &thread, 2, sizeof(struct thread **),
158                  test_dwarf_unwind__compare);
159         return global_unwind_retval;
160 }
161
162 noinline int test_dwarf_unwind__krava_2(struct thread *thread)
163 {
164         return test_dwarf_unwind__krava_3(thread);
165 }
166
167 noinline int test_dwarf_unwind__krava_1(struct thread *thread)
168 {
169         return test_dwarf_unwind__krava_2(thread);
170 }
171
172 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused)
173 {
174         struct machine *machine;
175         struct thread *thread;
176         int err = -1;
177
178         machine = machine__new_host();
179         if (!machine) {
180                 pr_err("Could not get machine\n");
181                 return -1;
182         }
183
184         if (machine__create_kernel_maps(machine)) {
185                 pr_err("Failed to create kernel maps\n");
186                 return -1;
187         }
188
189         callchain_param.record_mode = CALLCHAIN_DWARF;
190         dwarf_callchain_users = true;
191
192         if (init_live_machine(machine)) {
193                 pr_err("Could not init machine\n");
194                 goto out;
195         }
196
197         if (verbose > 1)
198                 machine__fprintf(machine, stderr);
199
200         thread = machine__find_thread(machine, getpid(), getpid());
201         if (!thread) {
202                 pr_err("Could not get thread\n");
203                 goto out;
204         }
205
206         err = test_dwarf_unwind__krava_1(thread);
207         thread__put(thread);
208
209  out:
210         machine__delete_threads(machine);
211         machine__delete(machine);
212         return err;
213 }