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 /* 41 * We need to keep these functions global, despite the 42 * fact that they are used only locally in this object, 43 * in order to keep them around even if the binary is 44 * stripped. If they are gone, the unwind check for 45 * symbol fails. 46 */ 47 int test_dwarf_unwind__thread(struct thread *thread); 48 int test_dwarf_unwind__compare(void *p1, void *p2); 49 int test_dwarf_unwind__krava_3(struct thread *thread); 50 int test_dwarf_unwind__krava_2(struct thread *thread); 51 int test_dwarf_unwind__krava_1(struct thread *thread); 52 53 #define MAX_STACK 8 54 55 static int unwind_entry(struct unwind_entry *entry, void *arg) 56 { 57 unsigned long *cnt = (unsigned long *) arg; 58 char *symbol = entry->sym ? entry->sym->name : NULL; 59 static const char *funcs[MAX_STACK] = { 60 "test__arch_unwind_sample", 61 "test_dwarf_unwind__thread", 62 "test_dwarf_unwind__compare", 63 "bsearch", 64 "test_dwarf_unwind__krava_3", 65 "test_dwarf_unwind__krava_2", 66 "test_dwarf_unwind__krava_1", 67 "test__dwarf_unwind" 68 }; 69 /* 70 * The funcs[MAX_STACK] array index, based on the 71 * callchain order setup. 72 */ 73 int idx = callchain_param.order == ORDER_CALLER ? 74 MAX_STACK - *cnt - 1 : *cnt; 75 76 if (*cnt >= MAX_STACK) { 77 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); 78 return -1; 79 } 80 81 if (!symbol) { 82 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", 83 entry->ip); 84 return -1; 85 } 86 87 (*cnt)++; 88 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", 89 symbol, entry->ip, funcs[idx]); 90 return strcmp((const char *) symbol, funcs[idx]); 91 } 92 93 noinline int test_dwarf_unwind__thread(struct thread *thread) 94 { 95 struct perf_sample sample; 96 unsigned long cnt = 0; 97 int err = -1; 98 99 memset(&sample, 0, sizeof(sample)); 100 101 if (test__arch_unwind_sample(&sample, thread)) { 102 pr_debug("failed to get unwind sample\n"); 103 goto out; 104 } 105 106 err = unwind__get_entries(unwind_entry, &cnt, thread, 107 &sample, MAX_STACK); 108 if (err) 109 pr_debug("unwind failed\n"); 110 else if (cnt != MAX_STACK) { 111 pr_debug("got wrong number of stack entries %lu != %d\n", 112 cnt, MAX_STACK); 113 err = -1; 114 } 115 116 out: 117 free(sample.user_stack.data); 118 free(sample.user_regs.regs); 119 return err; 120 } 121 122 static int global_unwind_retval = -INT_MAX; 123 124 noinline int test_dwarf_unwind__compare(void *p1, void *p2) 125 { 126 /* Any possible value should be 'thread' */ 127 struct thread *thread = *(struct thread **)p1; 128 129 if (global_unwind_retval == -INT_MAX) { 130 /* Call unwinder twice for both callchain orders. */ 131 callchain_param.order = ORDER_CALLER; 132 133 global_unwind_retval = test_dwarf_unwind__thread(thread); 134 if (!global_unwind_retval) { 135 callchain_param.order = ORDER_CALLEE; 136 global_unwind_retval = test_dwarf_unwind__thread(thread); 137 } 138 } 139 140 return p1 - p2; 141 } 142 143 noinline int test_dwarf_unwind__krava_3(struct thread *thread) 144 { 145 struct thread *array[2] = {thread, thread}; 146 void *fp = &bsearch; 147 /* 148 * make _bsearch a volatile function pointer to 149 * prevent potential optimization, which may expand 150 * bsearch and call compare directly from this function, 151 * instead of libc shared object. 152 */ 153 void *(*volatile _bsearch)(void *, void *, size_t, 154 size_t, int (*)(void *, void *)); 155 156 _bsearch = fp; 157 _bsearch(array, &thread, 2, sizeof(struct thread **), 158 test_dwarf_unwind__compare); 159 return global_unwind_retval; 160 } 161 162 noinline int test_dwarf_unwind__krava_2(struct thread *thread) 163 { 164 return test_dwarf_unwind__krava_3(thread); 165 } 166 167 noinline int test_dwarf_unwind__krava_1(struct thread *thread) 168 { 169 return test_dwarf_unwind__krava_2(thread); 170 } 171 172 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused) 173 { 174 struct machine *machine; 175 struct thread *thread; 176 int err = -1; 177 178 machine = machine__new_host(); 179 if (!machine) { 180 pr_err("Could not get machine\n"); 181 return -1; 182 } 183 184 if (machine__create_kernel_maps(machine)) { 185 pr_err("Failed to create kernel maps\n"); 186 return -1; 187 } 188 189 callchain_param.record_mode = CALLCHAIN_DWARF; 190 dwarf_callchain_users = true; 191 192 if (init_live_machine(machine)) { 193 pr_err("Could not init machine\n"); 194 goto out; 195 } 196 197 if (verbose > 1) 198 machine__fprintf(machine, stderr); 199 200 thread = machine__find_thread(machine, getpid(), getpid()); 201 if (!thread) { 202 pr_err("Could not get thread\n"); 203 goto out; 204 } 205 206 err = test_dwarf_unwind__krava_1(thread); 207 thread__put(thread); 208 209 out: 210 machine__delete_threads(machine); 211 machine__delete(machine); 212 return err; 213 } 214