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 memset(&event, 0, sizeof(event)); 41 return perf_event__synthesize_mmap_events(NULL, &event, pid, pid, 42 mmap_handler, machine, true); 43 } 44 45 /* 46 * We need to keep these functions global, despite the 47 * fact that they are used only locally in this object, 48 * in order to keep them around even if the binary is 49 * stripped. If they are gone, the unwind check for 50 * symbol fails. 51 */ 52 int test_dwarf_unwind__thread(struct thread *thread); 53 int test_dwarf_unwind__compare(void *p1, void *p2); 54 int test_dwarf_unwind__krava_3(struct thread *thread); 55 int test_dwarf_unwind__krava_2(struct thread *thread); 56 int test_dwarf_unwind__krava_1(struct thread *thread); 57 58 #define MAX_STACK 8 59 60 static int unwind_entry(struct unwind_entry *entry, void *arg) 61 { 62 unsigned long *cnt = (unsigned long *) arg; 63 char *symbol = entry->ms.sym ? entry->ms.sym->name : NULL; 64 static const char *funcs[MAX_STACK] = { 65 "test__arch_unwind_sample", 66 "test_dwarf_unwind__thread", 67 "test_dwarf_unwind__compare", 68 "bsearch", 69 "test_dwarf_unwind__krava_3", 70 "test_dwarf_unwind__krava_2", 71 "test_dwarf_unwind__krava_1", 72 "test__dwarf_unwind" 73 }; 74 /* 75 * The funcs[MAX_STACK] array index, based on the 76 * callchain order setup. 77 */ 78 int idx = callchain_param.order == ORDER_CALLER ? 79 MAX_STACK - *cnt - 1 : *cnt; 80 81 if (*cnt >= MAX_STACK) { 82 pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); 83 return -1; 84 } 85 86 if (!symbol) { 87 pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", 88 entry->ip); 89 return -1; 90 } 91 92 (*cnt)++; 93 pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", 94 symbol, entry->ip, funcs[idx]); 95 return strcmp((const char *) symbol, funcs[idx]); 96 } 97 98 __no_tail_call noinline int test_dwarf_unwind__thread(struct thread *thread) 99 { 100 struct perf_sample sample; 101 unsigned long cnt = 0; 102 int err = -1; 103 104 memset(&sample, 0, sizeof(sample)); 105 106 if (test__arch_unwind_sample(&sample, thread)) { 107 pr_debug("failed to get unwind sample\n"); 108 goto out; 109 } 110 111 err = unwind__get_entries(unwind_entry, &cnt, thread, 112 &sample, MAX_STACK); 113 if (err) 114 pr_debug("unwind failed\n"); 115 else if (cnt != MAX_STACK) { 116 pr_debug("got wrong number of stack entries %lu != %d\n", 117 cnt, MAX_STACK); 118 err = -1; 119 } 120 121 out: 122 zfree(&sample.user_stack.data); 123 zfree(&sample.user_regs.regs); 124 return err; 125 } 126 127 static int global_unwind_retval = -INT_MAX; 128 129 __no_tail_call noinline int test_dwarf_unwind__compare(void *p1, void *p2) 130 { 131 /* Any possible value should be 'thread' */ 132 struct thread *thread = *(struct thread **)p1; 133 134 if (global_unwind_retval == -INT_MAX) { 135 /* Call unwinder twice for both callchain orders. */ 136 callchain_param.order = ORDER_CALLER; 137 138 global_unwind_retval = test_dwarf_unwind__thread(thread); 139 if (!global_unwind_retval) { 140 callchain_param.order = ORDER_CALLEE; 141 global_unwind_retval = test_dwarf_unwind__thread(thread); 142 } 143 } 144 145 return p1 - p2; 146 } 147 148 __no_tail_call noinline int test_dwarf_unwind__krava_3(struct thread *thread) 149 { 150 struct thread *array[2] = {thread, thread}; 151 void *fp = &bsearch; 152 /* 153 * make _bsearch a volatile function pointer to 154 * prevent potential optimization, which may expand 155 * bsearch and call compare directly from this function, 156 * instead of libc shared object. 157 */ 158 void *(*volatile _bsearch)(void *, void *, size_t, 159 size_t, int (*)(void *, void *)); 160 161 _bsearch = fp; 162 _bsearch(array, &thread, 2, sizeof(struct thread **), 163 test_dwarf_unwind__compare); 164 return global_unwind_retval; 165 } 166 167 __no_tail_call noinline int test_dwarf_unwind__krava_2(struct thread *thread) 168 { 169 return test_dwarf_unwind__krava_3(thread); 170 } 171 172 __no_tail_call noinline int test_dwarf_unwind__krava_1(struct thread *thread) 173 { 174 return test_dwarf_unwind__krava_2(thread); 175 } 176 177 int test__dwarf_unwind(struct test *test __maybe_unused, int subtest __maybe_unused) 178 { 179 struct machine *machine; 180 struct thread *thread; 181 int err = -1; 182 183 machine = machine__new_host(); 184 if (!machine) { 185 pr_err("Could not get machine\n"); 186 return -1; 187 } 188 189 if (machine__create_kernel_maps(machine)) { 190 pr_err("Failed to create kernel maps\n"); 191 return -1; 192 } 193 194 callchain_param.record_mode = CALLCHAIN_DWARF; 195 dwarf_callchain_users = true; 196 197 if (init_live_machine(machine)) { 198 pr_err("Could not init machine\n"); 199 goto out; 200 } 201 202 if (verbose > 1) 203 machine__fprintf(machine, stderr); 204 205 thread = machine__find_thread(machine, getpid(), getpid()); 206 if (!thread) { 207 pr_err("Could not get thread\n"); 208 goto out; 209 } 210 211 err = test_dwarf_unwind__krava_1(thread); 212 thread__put(thread); 213 214 out: 215 machine__delete_threads(machine); 216 machine__delete(machine); 217 return err; 218 } 219