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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 | #include <linux/compiler.h>
#include <linux/types.h>
#include <unistd.h>
#include "tests.h"
#include "debug.h"
#include "machine.h"
#include "event.h"
#include "unwind.h"
#include "perf_regs.h"
#include "map.h"
#include "thread.h"
#include "callchain.h"
#if defined (__x86_64__) || defined (__i386__)
#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 __maybe_unused,
struct machine *machine)
{
return machine__process_mmap2_event(machine, event, NULL);
}
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, 500);
}
#define MAX_STACK 8
static int unwind_entry(struct unwind_entry *entry, void *arg)
{
unsigned long *cnt = (unsigned long *) arg;
char *symbol = entry->sym ? entry->sym->name : NULL;
static const char *funcs[MAX_STACK] = {
"test__arch_unwind_sample",
"unwind_thread",
"compare",
"bsearch",
"krava_3",
"krava_2",
"krava_1",
"test__dwarf_unwind"
};
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;
}
pr_debug("got: %s 0x%" PRIx64 "\n", symbol, entry->ip);
return strcmp((const char *) symbol, funcs[(*cnt)++]);
}
__attribute__ ((noinline))
static int 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:
free(sample.user_stack.data);
free(sample.user_regs.regs);
return err;
}
static int global_unwind_retval = -INT_MAX;
__attribute__ ((noinline))
static int compare(void *p1, void *p2)
{
/* Any possible value should be 'thread' */
struct thread *thread = *(struct thread **)p1;
if (global_unwind_retval == -INT_MAX)
global_unwind_retval = unwind_thread(thread);
return p1 - p2;
}
__attribute__ ((noinline))
static int 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 **), compare);
return global_unwind_retval;
}
__attribute__ ((noinline))
static int krava_2(struct thread *thread)
{
return krava_3(thread);
}
__attribute__ ((noinline))
static int krava_1(struct thread *thread)
{
return krava_2(thread);
}
int test__dwarf_unwind(void)
{
struct machines machines;
struct machine *machine;
struct thread *thread;
int err = -1;
machines__init(&machines);
machine = machines__find(&machines, HOST_KERNEL_ID);
if (!machine) {
pr_err("Could not get machine\n");
return -1;
}
callchain_param.record_mode = CALLCHAIN_DWARF;
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 = krava_1(thread);
thread__put(thread);
out:
machine__delete_threads(machine);
machine__exit(machine);
machines__exit(&machines);
return err;
}
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