kernel/tools/testing/selftests/powerpc/pmu/ebb/ebb_on_child_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 we can setup an EBB on our child. Nothing interesting happens, because
  19  * even though the event is enabled and running the child hasn't enabled the
  20  * actual delivery of the EBBs.
  21  */
  22
  23 static int victim_child(union pipe read_pipe, union pipe write_pipe)
  24 {
  25         int i;
  26
  27         FAIL_IF(wait_for_parent(read_pipe));
  28         FAIL_IF(notify_parent(write_pipe));
  29
  30         /* Parent creates EBB event */
  31
  32         FAIL_IF(wait_for_parent(read_pipe));
  33         FAIL_IF(notify_parent(write_pipe));
  34
  35         /* Check the EBB is enabled by writing PMC1 */
  36         write_pmc1();
  37
  38         /* EBB event is enabled here */
  39         for (i = 0; i < 1000000; i++) ;
  40
  41         return 0;
  42 }
  43
  44 int ebb_on_child(void)
  45 {
  46         union pipe read_pipe, write_pipe;
  47         struct event event;
  48         pid_t pid;
  49
  50         SKIP_IF(!ebb_is_supported());
  51
  52         FAIL_IF(pipe(read_pipe.fds) == -1);
  53         FAIL_IF(pipe(write_pipe.fds) == -1);
  54
  55         pid = fork();
  56         if (pid == 0) {
  57                 /* NB order of pipes looks reversed */
  58                 exit(victim_child(write_pipe, read_pipe));
  59         }
  60
  61         FAIL_IF(sync_with_child(read_pipe, write_pipe));
  62
  63         /* Child is running now */
  64
  65         event_init_named(&event, 0x1001e, "cycles");
  66         event_leader_ebb_init(&event);
  67
  68         event.attr.exclude_kernel = 1;
  69         event.attr.exclude_hv = 1;
  70         event.attr.exclude_idle = 1;
  71
  72         FAIL_IF(event_open_with_pid(&event, pid));
  73         FAIL_IF(ebb_event_enable(&event));
  74
  75         FAIL_IF(sync_with_child(read_pipe, write_pipe));
  76
  77         /* Child should just exit happily */
  78         FAIL_IF(wait_for_child(pid));
  79
  80         event_close(&event);
  81
  82         return 0;
  83 }
  84
  85 int main(void)
  86 {
  87         return test_harness(ebb_on_child, "ebb_on_child");
  88 }