1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/compiler.h> 3 #include <linux/types.h> 4 #include <linux/zalloc.h> 5 #include <inttypes.h> 6 #include <unistd.h> 7 #include "tests.h" 8 #include "debug.h" 9 #include "machine.h" 10 #include "event.h" 11 #include "../util/unwind.h" 12 #include "perf_regs.h" 13 #include "map.h" 14 #include "symbol.h" 15 #include "thread.h" 16 #include "callchain.h" 17 18 #if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__) 19 #include "arch-tests.h" 20 #endif 21 22 /* For bsearch. We try to unwind functions in shared object. */ 23 #include <stdlib.h> 24 25 static int mmap_handler(struct perf_tool *tool __maybe_unused, 26 union perf_event *event, 27 struct perf_sample *sample, 28 struct machine *machine) 29 { 30 return machine__process_mmap2_event(machine, event, sample); 31 } 32 33 static int init_live_machine(struct machine *machine) 34 { 35 union perf_event event; 36 pid_t pid = getpid(); 37 38 return perf_event__synthesize_mmap_events(NULL, &event, pid, pid, 39 mmap_handler, machine, true); 40 } 41 42 /* 43 * We need to keep these functions global, despite the 44 * fact that they are used only locally in this object, 45 * in order to keep them around even if the binary is 46 * stripped. If they are gone, the unwind check for 47 * symbol fails. 48 */ 49 int test_dwarf_unwind__thread(struct thread *thread); 50 int test_dwarf_unwind__compare(void *p1, void *p2); 51 int test_dwarf_unwind__krava_3(struct thread *thread); 52 int test_dwarf_unwind__krava_2(struct thread *thread); 53 int test_dwarf_unwind__krava_1(struct thread *thread); 54 55 #define MAX_STACK 8 56 57 static int unwind_entry(struct unwind_entry *entry, void *arg) 58 { 59 unsigned long *cnt = (unsigned long *) arg; 60 char *symbol = entry->sym ? entry->sym->name : NULL; 61 static const char *funcs[MAX_STACK] = { 62 "test__arch_unwind_sample", 63 "test_dwarf_unwind__thread", 64 "test_dwarf_unwind__compare", 65 "bsearch", 66 "test_dwarf_unwind__krava_3", 67 "test_dwarf_unwind__krava_2", 68 "test_dwarf_unwind__krava_1", 69 "test__dwarf_unwind" 70 }; 71 /* 72 * The funcs[MAX_STACK] array index, based on the 73 * callchain order setup. 74 */ 75 int idx = callchain_param.order == ORDER_CALLER ? 76 MAX_STACK - *cnt - 1 : *cnt; 77 78 if (*cnt >= MAX_STACK) { 79 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); 80 return -1; 81 } 82 83 if (!symbol) { 84 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", 85 entry->ip); 86 return -1; 87 } 88 89 (*cnt)++; 90 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", 91 symbol, entry->ip, funcs[idx]); 92 return strcmp((const char *) symbol, funcs[idx]); 93 } 94 95 noinline int test_dwarf_unwind__thread(struct thread *thread) 96 { 97 struct perf_sample sample; 98 unsigned long cnt = 0; 99 int err = -1; 100 101 memset(&sample, 0, sizeof(sample)); 102 103 if (test__arch_unwind_sample(&sample, thread)) { 104 pr_debug("failed to get unwind sample\n"); 105 goto out; 106 } 107 108 err = unwind__get_entries(unwind_entry, &cnt, thread, 109 &sample, MAX_STACK); 110 if (err) 111 pr_debug("unwind failed\n"); 112 else if (cnt != MAX_STACK) { 113 pr_debug("got wrong number of stack entries %lu != %d\n", 114 cnt, MAX_STACK); 115 err = -1; 116 } 117 118 out: 119 zfree(&sample.user_stack.data); 120 zfree(&sample.user_regs.regs); 121 return err; 122 } 123 124 static int global_unwind_retval = -INT_MAX; 125 126 noinline int test_dwarf_unwind__compare(void *p1, void *p2) 127 { 128 /* Any possible value should be 'thread' */ 129 struct thread *thread = *(struct thread **)p1; 130 131 if (global_unwind_retval == -INT_MAX) { 132 /* Call unwinder twice for both callchain orders. */ 133 callchain_param.order = ORDER_CALLER; 134 135 global_unwind_retval = test_dwarf_unwind__thread(thread); 136 if (!global_unwind_retval) { 137 callchain_param.order = ORDER_CALLEE; 138 global_unwind_retval = test_dwarf_unwind__thread(thread); 139 } 140 } 141 142 return p1 - p2; 143 } 144 145 noinline int test_dwarf_unwind__krava_3(struct thread *thread) 146 { 147 struct thread *array[2] = {thread, thread}; 148 void *fp = &bsearch; 149 /* 150 * make _bsearch a volatile function pointer to 151 * prevent potential optimization, which may expand 152 * bsearch and call compare directly from this function, 153 * instead of libc shared object. 154 */ 155 void *(*volatile _bsearch)(void *, void *, size_t, 156 size_t, int (*)(void *, void *)); 157 158 _bsearch = fp; 159 _bsearch(array, &thread, 2, sizeof(struct thread **), 160 test_dwarf_unwind__compare); 161 return global_unwind_retval; 162 } 163 164 noinline int test_dwarf_unwind__krava_2(struct thread *thread) 165 { 166 return test_dwarf_unwind__krava_3(thread); 167 } 168 169 noinline int test_dwarf_unwind__krava_1(struct thread *thread) 170 { 171 return test_dwarf_unwind__krava_2(thread); 172 } 173 174 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused) 175 { 176 struct machine *machine; 177 struct thread *thread; 178 int err = -1; 179 180 machine = machine__new_host(); 181 if (!machine) { 182 pr_err("Could not get machine\n"); 183 return -1; 184 } 185 186 if (machine__create_kernel_maps(machine)) { 187 pr_err("Failed to create kernel maps\n"); 188 return -1; 189 } 190 191 callchain_param.record_mode = CALLCHAIN_DWARF; 192 dwarf_callchain_users = true; 193 194 if (init_live_machine(machine)) { 195 pr_err("Could not init machine\n"); 196 goto out; 197 } 198 199 if (verbose > 1) 200 machine__fprintf(machine, stderr); 201 202 thread = machine__find_thread(machine, getpid(), getpid()); 203 if (!thread) { 204 pr_err("Could not get thread\n"); 205 goto out; 206 } 207 208 err = test_dwarf_unwind__krava_1(thread); 209 thread__put(thread); 210 211 out: 212 machine__delete_threads(machine); 213 machine__delete(machine); 214 return err; 215 } 216