tools/perf/tests/dwarf-unwind.c

   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__)
  15 #include "arch-tests.h"
  16 #endif
  17
  18 /* For bsearch. We try to unwind functions in shared object. */
  19 #include <stdlib.h>
  20
  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
  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
  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))
  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))
 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))
 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))
 150 static int krava_2(struct thread *thread)
 151 {
 152         return krava_3(thread);
 153 }
 154
 155 __attribute__ ((noinline))
 156 static int krava_1(struct thread *thread)
 157 {
 158         return krava_2(thread);
 159 }
 160
 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 }