| #include <linux/compiler.h> |
| #include <linux/types.h> |
| #include <unistd.h> |
| #include "tests.h" |
| #include "debug.h" |
| #include "machine.h" |
| #include "event.h" |
| #include "unwind.h" |
| #include "perf_regs.h" |
| #include "map.h" |
| #include "thread.h" |
| #include "callchain.h" |
| |
| #if defined (__x86_64__) || defined (__i386__) |
| #include "arch-tests.h" |
| #endif |
| |
| /* For bsearch. We try to unwind functions in shared object. */ |
| #include <stdlib.h> |
| |
| static int mmap_handler(struct perf_tool *tool __maybe_unused, |
| union perf_event *event, |
| struct perf_sample *sample __maybe_unused, |
| struct machine *machine) |
| { |
| return machine__process_mmap2_event(machine, event, NULL); |
| } |
| |
| static int init_live_machine(struct machine *machine) |
| { |
| union perf_event event; |
| pid_t pid = getpid(); |
| |
| return perf_event__synthesize_mmap_events(NULL, &event, pid, pid, |
| mmap_handler, machine, true, 500); |
| } |
| |
| #define MAX_STACK 8 |
| |
| static int unwind_entry(struct unwind_entry *entry, void *arg) |
| { |
| unsigned long *cnt = (unsigned long *) arg; |
| char *symbol = entry->sym ? entry->sym->name : NULL; |
| static const char *funcs[MAX_STACK] = { |
| "test__arch_unwind_sample", |
| "unwind_thread", |
| "compare", |
| "bsearch", |
| "krava_3", |
| "krava_2", |
| "krava_1", |
| "test__dwarf_unwind" |
| }; |
| /* |
| * The funcs[MAX_STACK] array index, based on the |
| * callchain order setup. |
| */ |
| int idx = callchain_param.order == ORDER_CALLER ? |
| MAX_STACK - *cnt - 1 : *cnt; |
| |
| if (*cnt >= MAX_STACK) { |
| pr_debug("failed: crossed the max stack value %d\n", MAX_STACK); |
| return -1; |
| } |
| |
| if (!symbol) { |
| pr_debug("failed: got unresolved address 0x%" PRIx64 "\n", |
| entry->ip); |
| return -1; |
| } |
| |
| (*cnt)++; |
| pr_debug("got: %s 0x%" PRIx64 ", expecting %s\n", |
| symbol, entry->ip, funcs[idx]); |
| return strcmp((const char *) symbol, funcs[idx]); |
| } |
| |
| __attribute__ ((noinline)) |
| static int unwind_thread(struct thread *thread) |
| { |
| struct perf_sample sample; |
| unsigned long cnt = 0; |
| int err = -1; |
| |
| memset(&sample, 0, sizeof(sample)); |
| |
| if (test__arch_unwind_sample(&sample, thread)) { |
| pr_debug("failed to get unwind sample\n"); |
| goto out; |
| } |
| |
| err = unwind__get_entries(unwind_entry, &cnt, thread, |
| &sample, MAX_STACK); |
| if (err) |
| pr_debug("unwind failed\n"); |
| else if (cnt != MAX_STACK) { |
| pr_debug("got wrong number of stack entries %lu != %d\n", |
| cnt, MAX_STACK); |
| err = -1; |
| } |
| |
| out: |
| free(sample.user_stack.data); |
| free(sample.user_regs.regs); |
| return err; |
| } |
| |
| static int global_unwind_retval = -INT_MAX; |
| |
| __attribute__ ((noinline)) |
| static int compare(void *p1, void *p2) |
| { |
| /* Any possible value should be 'thread' */ |
| struct thread *thread = *(struct thread **)p1; |
| |
| if (global_unwind_retval == -INT_MAX) { |
| /* Call unwinder twice for both callchain orders. */ |
| callchain_param.order = ORDER_CALLER; |
| |
| global_unwind_retval = unwind_thread(thread); |
| if (!global_unwind_retval) { |
| callchain_param.order = ORDER_CALLEE; |
| global_unwind_retval = unwind_thread(thread); |
| } |
| } |
| |
| return p1 - p2; |
| } |
| |
| __attribute__ ((noinline)) |
| static int krava_3(struct thread *thread) |
| { |
| struct thread *array[2] = {thread, thread}; |
| void *fp = &bsearch; |
| /* |
| * make _bsearch a volatile function pointer to |
| * prevent potential optimization, which may expand |
| * bsearch and call compare directly from this function, |
| * instead of libc shared object. |
| */ |
| void *(*volatile _bsearch)(void *, void *, size_t, |
| size_t, int (*)(void *, void *)); |
| |
| _bsearch = fp; |
| _bsearch(array, &thread, 2, sizeof(struct thread **), compare); |
| return global_unwind_retval; |
| } |
| |
| __attribute__ ((noinline)) |
| static int krava_2(struct thread *thread) |
| { |
| return krava_3(thread); |
| } |
| |
| __attribute__ ((noinline)) |
| static int krava_1(struct thread *thread) |
| { |
| return krava_2(thread); |
| } |
| |
| int test__dwarf_unwind(int subtest __maybe_unused) |
| { |
| struct machines machines; |
| struct machine *machine; |
| struct thread *thread; |
| int err = -1; |
| |
| machines__init(&machines); |
| |
| machine = machines__find(&machines, HOST_KERNEL_ID); |
| if (!machine) { |
| pr_err("Could not get machine\n"); |
| return -1; |
| } |
| |
| callchain_param.record_mode = CALLCHAIN_DWARF; |
| |
| if (init_live_machine(machine)) { |
| pr_err("Could not init machine\n"); |
| goto out; |
| } |
| |
| if (verbose > 1) |
| machine__fprintf(machine, stderr); |
| |
| thread = machine__find_thread(machine, getpid(), getpid()); |
| if (!thread) { |
| pr_err("Could not get thread\n"); |
| goto out; |
| } |
| |
| err = krava_1(thread); |
| thread__put(thread); |
| |
| out: |
| machine__delete_threads(machine); |
| machine__exit(machine); |
| machines__exit(&machines); |
| return err; |
| } |