1 #include <linux/compiler.h> 2 #include <linux/types.h> 3 #include <inttypes.h> 4 #include <unistd.h> 5 #include "tests.h" 6 #include "debug.h" 7 #include "machine.h" 8 #include "event.h" 9 #include "unwind.h" 10 #include "perf_regs.h" 11 #include "map.h" 12 #include "thread.h" 13 #include "callchain.h" 14 15 #if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__) 16 #include "arch-tests.h" 17 #endif 18 19 /* For bsearch. We try to unwind functions in shared object. */ 20 #include <stdlib.h> 21 22 static int mmap_handler(struct perf_tool *tool __maybe_unused, 23 union perf_event *event, 24 struct perf_sample *sample, 25 struct machine *machine) 26 { 27 return machine__process_mmap2_event(machine, event, sample); 28 } 29 30 static int init_live_machine(struct machine *machine) 31 { 32 union perf_event event; 33 pid_t pid = getpid(); 34 35 return perf_event__synthesize_mmap_events(NULL, &event, pid, pid, 36 mmap_handler, machine, true, 500); 37 } 38 39 #define MAX_STACK 8 40 41 static int unwind_entry(struct unwind_entry *entry, void *arg) 42 { 43 unsigned long *cnt = (unsigned long *) arg; 44 char *symbol = entry->sym ? entry->sym->name : NULL; 45 static const char *funcs[MAX_STACK] = { 46 "test__arch_unwind_sample", 47 "unwind_thread", 48 "compare", 49 "bsearch", 50 "krava_3", 51 "krava_2", 52 "krava_1", 53 "test__dwarf_unwind" 54 }; 55 /* 56 * The funcs[MAX_STACK] array index, based on the 57 * callchain order setup. 58 */ 59 int idx = callchain_param.order == ORDER_CALLER ? 60 MAX_STACK - *cnt - 1 : *cnt; 61 62 if (*cnt >= MAX_STACK) { 63 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); 64 return -1; 65 } 66 67 if (!symbol) { 68 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", 69 entry->ip); 70 return -1; 71 } 72 73 (*cnt)++; 74 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", 75 symbol, entry->ip, funcs[idx]); 76 return strcmp((const char *) symbol, funcs[idx]); 77 } 78 79 static noinline 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 static noinline int compare(void *p1, void *p2) 111 { 112 /* Any possible value should be 'thread' */ 113 struct thread *thread = *(struct thread **)p1; 114 115 if (global_unwind_retval == -INT_MAX) { 116 /* Call unwinder twice for both callchain orders. */ 117 callchain_param.order = ORDER_CALLER; 118 119 global_unwind_retval = unwind_thread(thread); 120 if (!global_unwind_retval) { 121 callchain_param.order = ORDER_CALLEE; 122 global_unwind_retval = unwind_thread(thread); 123 } 124 } 125 126 return p1 - p2; 127 } 128 129 static noinline int krava_3(struct thread *thread) 130 { 131 struct thread *array[2] = {thread, thread}; 132 void *fp = &bsearch; 133 /* 134 * make _bsearch a volatile function pointer to 135 * prevent potential optimization, which may expand 136 * bsearch and call compare directly from this function, 137 * instead of libc shared object. 138 */ 139 void *(*volatile _bsearch)(void *, void *, size_t, 140 size_t, int (*)(void *, void *)); 141 142 _bsearch = fp; 143 _bsearch(array, &thread, 2, sizeof(struct thread **), compare); 144 return global_unwind_retval; 145 } 146 147 static noinline int krava_2(struct thread *thread) 148 { 149 return krava_3(thread); 150 } 151 152 static noinline int krava_1(struct thread *thread) 153 { 154 return krava_2(thread); 155 } 156 157 int test__dwarf_unwind(int subtest __maybe_unused) 158 { 159 struct machine *machine; 160 struct thread *thread; 161 int err = -1; 162 163 machine = machine__new_host(); 164 if (!machine) { 165 pr_err("Could not get machine\n"); 166 return -1; 167 } 168 169 if (machine__create_kernel_maps(machine)) { 170 pr_err("Failed to create kernel maps\n"); 171 return -1; 172 } 173 174 callchain_param.record_mode = CALLCHAIN_DWARF; 175 176 if (init_live_machine(machine)) { 177 pr_err("Could not init machine\n"); 178 goto out; 179 } 180 181 if (verbose > 1) 182 machine__fprintf(machine, stderr); 183 184 thread = machine__find_thread(machine, getpid(), getpid()); 185 if (!thread) { 186 pr_err("Could not get thread\n"); 187 goto out; 188 } 189 190 err = krava_1(thread); 191 thread__put(thread); 192 193 out: 194 machine__delete_threads(machine); 195 machine__delete(machine); 196 return err; 197 } 198