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 } 202