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 <limits.h> 7 #include <unistd.h> 8 #include "tests.h" 9 #include "debug.h" 10 #include "machine.h" 11 #include "event.h" 12 #include "../util/unwind.h" 13 #include "perf_regs.h" 14 #include "map.h" 15 #include "symbol.h" 16 #include "thread.h" 17 #include "callchain.h" 18 #include "util/synthetic-events.h" 19 20 #if defined (__x86_64__) || defined (__i386__) || defined (__powerpc__) 21 #include "arch-tests.h" 22 #endif 23 24 /* For bsearch. We try to unwind functions in shared object. */ 25 #include <stdlib.h> 26 27 static int mmap_handler(struct perf_tool *tool __maybe_unused, 28 union perf_event *event, 29 struct perf_sample *sample, 30 struct machine *machine) 31 { 32 return machine__process_mmap2_event(machine, event, sample); 33 } 34 35 static int init_live_machine(struct machine *machine) 36 { 37 union perf_event event; 38 pid_t pid = getpid(); 39 40 return perf_event__synthesize_mmap_events(NULL, &event, pid, pid, 41 mmap_handler, machine, true); 42 } 43 44 /* 45 * We need to keep these functions global, despite the 46 * fact that they are used only locally in this object, 47 * in order to keep them around even if the binary is 48 * stripped. If they are gone, the unwind check for 49 * symbol fails. 50 */ 51 int test_dwarf_unwind__thread(struct thread *thread); 52 int test_dwarf_unwind__compare(void *p1, void *p2); 53 int test_dwarf_unwind__krava_3(struct thread *thread); 54 int test_dwarf_unwind__krava_2(struct thread *thread); 55 int test_dwarf_unwind__krava_1(struct thread *thread); 56 57 #define MAX_STACK 8 58 59 static int unwind_entry(struct unwind_entry *entry, void *arg) 60 { 61 unsigned long *cnt = (unsigned long *) arg; 62 char *symbol = entry->sym ? entry->sym->name : NULL; 63 static const char *funcs[MAX_STACK] = { 64 "test__arch_unwind_sample", 65 "test_dwarf_unwind__thread", 66 "test_dwarf_unwind__compare", 67 "bsearch", 68 "test_dwarf_unwind__krava_3", 69 "test_dwarf_unwind__krava_2", 70 "test_dwarf_unwind__krava_1", 71 "test__dwarf_unwind" 72 }; 73 /* 74 * The funcs[MAX_STACK] array index, based on the 75 * callchain order setup. 76 */ 77 int idx = callchain_param.order == ORDER_CALLER ? 78 MAX_STACK - *cnt - 1 : *cnt; 79 80 if (*cnt >= MAX_STACK) { 81 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); 82 return -1; 83 } 84 85 if (!symbol) { 86 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", 87 entry->ip); 88 return -1; 89 } 90 91 (*cnt)++; 92 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", 93 symbol, entry->ip, funcs[idx]); 94 return strcmp((const char *) symbol, funcs[idx]); 95 } 96 97 noinline int test_dwarf_unwind__thread(struct thread *thread) 98 { 99 struct perf_sample sample; 100 unsigned long cnt = 0; 101 int err = -1; 102 103 memset(&sample, 0, sizeof(sample)); 104 105 if (test__arch_unwind_sample(&sample, thread)) { 106 pr_debug("failed to get unwind sample\n"); 107 goto out; 108 } 109 110 err = unwind__get_entries(unwind_entry, &cnt, thread, 111 &sample, MAX_STACK); 112 if (err) 113 pr_debug("unwind failed\n"); 114 else if (cnt != MAX_STACK) { 115 pr_debug("got wrong number of stack entries %lu != %d\n", 116 cnt, MAX_STACK); 117 err = -1; 118 } 119 120 out: 121 zfree(&sample.user_stack.data); 122 zfree(&sample.user_regs.regs); 123 return err; 124 } 125 126 static int global_unwind_retval = -INT_MAX; 127 128 noinline int test_dwarf_unwind__compare(void *p1, void *p2) 129 { 130 /* Any possible value should be 'thread' */ 131 struct thread *thread = *(struct thread **)p1; 132 133 if (global_unwind_retval == -INT_MAX) { 134 /* Call unwinder twice for both callchain orders. */ 135 callchain_param.order = ORDER_CALLER; 136 137 global_unwind_retval = test_dwarf_unwind__thread(thread); 138 if (!global_unwind_retval) { 139 callchain_param.order = ORDER_CALLEE; 140 global_unwind_retval = test_dwarf_unwind__thread(thread); 141 } 142 } 143 144 return p1 - p2; 145 } 146 147 noinline int test_dwarf_unwind__krava_3(struct thread *thread) 148 { 149 struct thread *array[2] = {thread, thread}; 150 void *fp = &bsearch; 151 /* 152 * make _bsearch a volatile function pointer to 153 * prevent potential optimization, which may expand 154 * bsearch and call compare directly from this function, 155 * instead of libc shared object. 156 */ 157 void *(*volatile _bsearch)(void *, void *, size_t, 158 size_t, int (*)(void *, void *)); 159 160 _bsearch = fp; 161 _bsearch(array, &thread, 2, sizeof(struct thread **), 162 test_dwarf_unwind__compare); 163 return global_unwind_retval; 164 } 165 166 noinline int test_dwarf_unwind__krava_2(struct thread *thread) 167 { 168 return test_dwarf_unwind__krava_3(thread); 169 } 170 171 noinline int test_dwarf_unwind__krava_1(struct thread *thread) 172 { 173 return test_dwarf_unwind__krava_2(thread); 174 } 175 176 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused) 177 { 178 struct machine *machine; 179 struct thread *thread; 180 int err = -1; 181 182 machine = machine__new_host(); 183 if (!machine) { 184 pr_err("Could not get machine\n"); 185 return -1; 186 } 187 188 if (machine__create_kernel_maps(machine)) { 189 pr_err("Failed to create kernel maps\n"); 190 return -1; 191 } 192 193 callchain_param.record_mode = CALLCHAIN_DWARF; 194 dwarf_callchain_users = true; 195 196 if (init_live_machine(machine)) { 197 pr_err("Could not init machine\n"); 198 goto out; 199 } 200 201 if (verbose > 1) 202 machine__fprintf(machine, stderr); 203 204 thread = machine__find_thread(machine, getpid(), getpid()); 205 if (!thread) { 206 pr_err("Could not get thread\n"); 207 goto out; 208 } 209 210 err = test_dwarf_unwind__krava_1(thread); 211 thread__put(thread); 212 213 out: 214 machine__delete_threads(machine); 215 machine__delete(machine); 216 return err; 217 } 218