kernel/tools/testing/selftests/powerpc/pmu/ebb/close_clears_pmcc_test.c

   1 /*
   2  * Copyright 2014, Michael Ellerman, IBM Corp.
   3  * Licensed under GPLv2.
   4  */
   5
   6 #include <stdio.h>
   7 #include <stdlib.h>
   8 #include <setjmp.h>
   9 #include <signal.h>
  10
  11 #include "ebb.h"
  12
  13
  14 /*
  15  * Test that closing the EBB event clears MMCR0_PMCC, preventing further access
  16  * by userspace to the PMU hardware.
  17  */
  18
  19 int close_clears_pmcc(void)
  20 {
  21         struct event event;
  22
  23         SKIP_IF(!ebb_is_supported());
  24
  25         event_init_named(&event, 0x1001e, "cycles");
  26         event_leader_ebb_init(&event);
  27
  28         FAIL_IF(event_open(&event));
  29
  30         ebb_enable_pmc_counting(1);
  31         setup_ebb_handler(standard_ebb_callee);
  32         ebb_global_enable();
  33         FAIL_IF(ebb_event_enable(&event));
  34
  35         mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
  36
  37         while (ebb_state.stats.ebb_count < 1)
  38                 FAIL_IF(core_busy_loop());
  39
  40         ebb_global_disable();
  41         event_close(&event);
  42
  43         FAIL_IF(ebb_state.stats.ebb_count == 0);
  44
  45         /* The real test is here, do we take a SIGILL when writing PMU regs now
  46          * that we have closed the event. We expect that we will. */
  47
  48         FAIL_IF(catch_sigill(write_pmc1));
  49
  50         /* We should still be able to read EBB regs though */
  51         mfspr(SPRN_EBBHR);
  52         mfspr(SPRN_EBBRR);
  53         mfspr(SPRN_BESCR);
  54
  55         return 0;
  56 }
  57
  58 int main(void)
  59 {
  60         return test_harness(close_clears_pmcc, "close_clears_pmcc");
  61 }