1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/compiler.h> 3 #include <linux/types.h> 4 #include <inttypes.h> 5 #include <unistd.h> 6 #include "tests.h" 7 #include "debug.h" 8 #include "machine.h" 9 #include "event.h" 10 #include "../util/unwind.h" 11 #include "perf_regs.h" 12 #include "map.h" 13 #include "thread.h" 14 #include "callchain.h" 15 16 #if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__) 17 #include "arch-tests.h" 18 #endif 19 20 /* For bsearch. We try to unwind functions in shared object. */ 21 #include <stdlib.h> 22 23 static int mmap_handler(struct perf_tool *tool __maybe_unused, 24 union perf_event *event, 25 struct perf_sample *sample, 26 struct machine *machine) 27 { 28 return machine__process_mmap2_event(machine, event, sample); 29 } 30 31 static int init_live_machine(struct machine *machine) 32 { 33 union perf_event event; 34 pid_t pid = getpid(); 35 36 return perf_event__synthesize_mmap_events(NULL, &event, pid, pid, 37 mmap_handler, machine, true, 500); 38 } 39 40 #define MAX_STACK 8 41 42 static int unwind_entry(struct unwind_entry *entry, void *arg) 43 { 44 unsigned long *cnt = (unsigned long *) arg; 45 char *symbol = entry->sym ? entry->sym->name : NULL; 46 static const char *funcs[MAX_STACK] = { 47 "test__arch_unwind_sample", 48 "unwind_thread", 49 "compare", 50 "bsearch", 51 "krava_3", 52 "krava_2", 53 "krava_1", 54 "test__dwarf_unwind" 55 }; 56 /* 57 * The funcs[MAX_STACK] array index, based on the 58 * callchain order setup. 59 */ 60 int idx = callchain_param.order == ORDER_CALLER ? 61 MAX_STACK - *cnt - 1 : *cnt; 62 63 if (*cnt >= MAX_STACK) { 64 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); 65 return -1; 66 } 67 68 if (!symbol) { 69 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", 70 entry->ip); 71 return -1; 72 } 73 74 (*cnt)++; 75 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", 76 symbol, entry->ip, funcs[idx]); 77 return strcmp((const char *) symbol, funcs[idx]); 78 } 79 80 static noinline int unwind_thread(struct thread *thread) 81 { 82 struct perf_sample sample; 83 unsigned long cnt = 0; 84 int err = -1; 85 86 memset(&sample, 0, sizeof(sample)); 87 88 if (test__arch_unwind_sample(&sample, thread)) { 89 pr_debug("failed to get unwind sample\n"); 90 goto out; 91 } 92 93 err = unwind__get_entries(unwind_entry, &cnt, thread, 94 &sample, MAX_STACK); 95 if (err) 96 pr_debug("unwind failed\n"); 97 else if (cnt != MAX_STACK) { 98 pr_debug("got wrong number of stack entries %lu != %d\n", 99 cnt, MAX_STACK); 100 err = -1; 101 } 102 103 out: 104 free(sample.user_stack.data); 105 free(sample.user_regs.regs); 106 return err; 107 } 108 109 static int global_unwind_retval = -INT_MAX; 110 111 static noinline 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 static noinline int krava_3(struct thread *thread) 131 { 132 struct thread *array[2] = {thread, thread}; 133 void *fp = &bsearch; 134 /* 135 * make _bsearch a volatile function pointer to 136 * prevent potential optimization, which may expand 137 * bsearch and call compare directly from this function, 138 * instead of libc shared object. 139 */ 140 void *(*volatile _bsearch)(void *, void *, size_t, 141 size_t, int (*)(void *, void *)); 142 143 _bsearch = fp; 144 _bsearch(array, &thread, 2, sizeof(struct thread **), compare); 145 return global_unwind_retval; 146 } 147 148 static noinline int krava_2(struct thread *thread) 149 { 150 return krava_3(thread); 151 } 152 153 static noinline int krava_1(struct thread *thread) 154 { 155 return krava_2(thread); 156 } 157 158 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused) 159 { 160 struct machine *machine; 161 struct thread *thread; 162 int err = -1; 163 164 machine = machine__new_host(); 165 if (!machine) { 166 pr_err("Could not get machine\n"); 167 return -1; 168 } 169 170 if (machine__create_kernel_maps(machine)) { 171 pr_err("Failed to create kernel maps\n"); 172 return -1; 173 } 174 175 callchain_param.record_mode = CALLCHAIN_DWARF; 176 dwarf_callchain_users = true; 177 178 if (init_live_machine(machine)) { 179 pr_err("Could not init machine\n"); 180 goto out; 181 } 182 183 if (verbose > 1) 184 machine__fprintf(machine, stderr); 185 186 thread = machine__find_thread(machine, getpid(), getpid()); 187 if (!thread) { 188 pr_err("Could not get thread\n"); 189 goto out; 190 } 191 192 err = krava_1(thread); 193 thread__put(thread); 194 195 out: 196 machine__delete_threads(machine); 197 machine__delete(machine); 198 return err; 199 } 200