1 #include <linux/compiler.h>
2 #include <linux/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 #include "callchain.h"
13
14 #if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__)
15 #include "arch-tests.h"
16 #endif
17
18 /* For bsearch. We try to unwind functions in shared object. */
19 #include <stdlib.h>
20
mmap_handler(struct perf_tool * tool __maybe_unused,union perf_event * event,struct perf_sample * sample,struct machine * machine)21 static int mmap_handler(struct perf_tool *tool __maybe_unused,
22 union perf_event *event,
23 struct perf_sample *sample,
24 struct machine *machine)
25 {
26 return machine__process_mmap2_event(machine, event, sample);
27 }
28
init_live_machine(struct machine * machine)29 static int init_live_machine(struct machine *machine)
30 {
31 union perf_event event;
32 pid_t pid = getpid();
33
34 return perf_event__synthesize_mmap_events(NULL, &event, pid, pid,
35 mmap_handler, machine, true, 500);
36 }
37
38 #define MAX_STACK 8
39
unwind_entry(struct unwind_entry * entry,void * arg)40 static int unwind_entry(struct unwind_entry *entry, void *arg)
41 {
42 unsigned long *cnt = (unsigned long *) arg;
43 char *symbol = entry->sym ? entry->sym->name : NULL;
44 static const char *funcs[MAX_STACK] = {
45 "test__arch_unwind_sample",
46 "unwind_thread",
47 "compare",
48 "bsearch",
49 "krava_3",
50 "krava_2",
51 "krava_1",
52 "test__dwarf_unwind"
53 };
54 /*
55 * The funcs[MAX_STACK] array index, based on the
56 * callchain order setup.
57 */
58 int idx = callchain_param.order == ORDER_CALLER ?
59 MAX_STACK - *cnt - 1 : *cnt;
60
61 if (*cnt >= MAX_STACK) {
62 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK);
63 return -1;
64 }
65
66 if (!symbol) {
67 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n",
68 entry->ip);
69 return -1;
70 }
71
72 (*cnt)++;
73 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n",
74 symbol, entry->ip, funcs[idx]);
75 return strcmp((const char *) symbol, funcs[idx]);
76 }
77
78 __attribute__ ((noinline))
unwind_thread(struct thread * thread)79 static int unwind_thread(struct thread *thread)
80 {
81 struct perf_sample sample;
82 unsigned long cnt = 0;
83 int err = -1;
84
85 memset(&sample, 0, sizeof(sample));
86
87 if (test__arch_unwind_sample(&sample, thread)) {
88 pr_debug("failed to get unwind sample\n");
89 goto out;
90 }
91
92 err = unwind__get_entries(unwind_entry, &cnt, thread,
93 &sample, MAX_STACK);
94 if (err)
95 pr_debug("unwind failed\n");
96 else if (cnt != MAX_STACK) {
97 pr_debug("got wrong number of stack entries %lu != %d\n",
98 cnt, MAX_STACK);
99 err = -1;
100 }
101
102 out:
103 free(sample.user_stack.data);
104 free(sample.user_regs.regs);
105 return err;
106 }
107
108 static int global_unwind_retval = -INT_MAX;
109
110 __attribute__ ((noinline))
compare(void * p1,void * p2)111 static int compare(void *p1, void *p2)
112 {
113 /* Any possible value should be 'thread' */
114 struct thread *thread = *(struct thread **)p1;
115
116 if (global_unwind_retval == -INT_MAX) {
117 /* Call unwinder twice for both callchain orders. */
118 callchain_param.order = ORDER_CALLER;
119
120 global_unwind_retval = unwind_thread(thread);
121 if (!global_unwind_retval) {
122 callchain_param.order = ORDER_CALLEE;
123 global_unwind_retval = unwind_thread(thread);
124 }
125 }
126
127 return p1 - p2;
128 }
129
130 __attribute__ ((noinline))
krava_3(struct thread * thread)131 static int krava_3(struct thread *thread)
132 {
133 struct thread *array[2] = {thread, thread};
134 void *fp = &bsearch;
135 /*
136 * make _bsearch a volatile function pointer to
137 * prevent potential optimization, which may expand
138 * bsearch and call compare directly from this function,
139 * instead of libc shared object.
140 */
141 void *(*volatile _bsearch)(void *, void *, size_t,
142 size_t, int (*)(void *, void *));
143
144 _bsearch = fp;
145 _bsearch(array, &thread, 2, sizeof(struct thread **), compare);
146 return global_unwind_retval;
147 }
148
149 __attribute__ ((noinline))
krava_2(struct thread * thread)150 static int krava_2(struct thread *thread)
151 {
152 return krava_3(thread);
153 }
154
155 __attribute__ ((noinline))
krava_1(struct thread * thread)156 static int krava_1(struct thread *thread)
157 {
158 return krava_2(thread);
159 }
160
test__dwarf_unwind(int subtest __maybe_unused)161 int test__dwarf_unwind(int subtest __maybe_unused)
162 {
163 struct machine *machine;
164 struct thread *thread;
165 int err = -1;
166
167 machine = machine__new_host();
168 if (!machine) {
169 pr_err("Could not get machine\n");
170 return -1;
171 }
172
173 if (machine__create_kernel_maps(machine)) {
174 pr_err("Failed to create kernel maps\n");
175 return -1;
176 }
177
178 callchain_param.record_mode = CALLCHAIN_DWARF;
179
180 if (init_live_machine(machine)) {
181 pr_err("Could not init machine\n");
182 goto out;
183 }
184
185 if (verbose > 1)
186 machine__fprintf(machine, stderr);
187
188 thread = machine__find_thread(machine, getpid(), getpid());
189 if (!thread) {
190 pr_err("Could not get thread\n");
191 goto out;
192 }
193
194 err = krava_1(thread);
195 thread__put(thread);
196
197 out:
198 machine__delete_threads(machine);
199 machine__delete(machine);
200 return err;
201 }
202