tools/testing/selftests/powerpc/pmu/ebb/task_event_pinned_vs_ebb_test.c

   1 /*
   2  * Copyright 2014, Michael Ellerman, IBM Corp.
   3  * Licensed under GPLv2.
   4  */
   5
   6 #include <signal.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <stdbool.h>
  10 #include <sys/types.h>
  11 #include <sys/wait.h>
  12 #include <unistd.h>
  13
  14 #include "ebb.h"
  15
  16
  17 /*
  18  * Tests a pinned per-task event vs an EBB - in that order. The pinned per-task
  19  * event should prevent the EBB event from being enabled.
  20  */
  21
  22 static int setup_child_event(struct event *event, pid_t child_pid)
  23 {
  24         event_init_named(event, 0x400FA, "PM_RUN_INST_CMPL");
  25
  26         event->attr.pinned = 1;
  27
  28         event->attr.exclude_kernel = 1;
  29         event->attr.exclude_hv = 1;
  30         event->attr.exclude_idle = 1;
  31
  32         FAIL_IF(event_open_with_pid(event, child_pid));
  33         FAIL_IF(event_enable(event));
  34
  35         return 0;
  36 }
  37
  38 int task_event_pinned_vs_ebb(void)
  39 {
  40         union pipe read_pipe, write_pipe;
  41         struct event event;
  42         pid_t pid;
  43         int rc;
  44
  45         SKIP_IF(!ebb_is_supported());
  46
  47         FAIL_IF(pipe(read_pipe.fds) == -1);
  48         FAIL_IF(pipe(write_pipe.fds) == -1);
  49
  50         pid = fork();
  51         if (pid == 0) {
  52                 /* NB order of pipes looks reversed */
  53                 exit(ebb_child(write_pipe, read_pipe));
  54         }
  55
  56         /* We setup the task event first */
  57         rc = setup_child_event(&event, pid);
  58         if (rc) {
  59                 kill_child_and_wait(pid);
  60                 return rc;
  61         }
  62
  63         /* Signal the child to install its EBB event and wait */
  64         if (sync_with_child(read_pipe, write_pipe))
  65                 /* If it fails, wait for it to exit */
  66                 goto wait;
  67
  68         /* Signal the child to run */
  69         FAIL_IF(sync_with_child(read_pipe, write_pipe));
  70
  71 wait:
  72         /* We expect it to fail to read the event */
  73         FAIL_IF(wait_for_child(pid) != 2);
  74         FAIL_IF(event_disable(&event));
  75         FAIL_IF(event_read(&event));
  76
  77         event_report(&event);
  78
  79         FAIL_IF(event.result.value == 0);
  80         /*
  81          * For reasons I don't understand enabled is usually just slightly
  82          * lower than running. Would be good to confirm why.
  83          */
  84         FAIL_IF(event.result.enabled == 0);
  85         FAIL_IF(event.result.running == 0);
  86
  87         return 0;
  88 }
  89
  90 int main(void)
  91 {
  92         return test_harness(task_event_pinned_vs_ebb, "task_event_pinned_vs_ebb");
  93 }