kernel/tools/testing/selftests/powerpc/pmu/ebb/pmc56_overflow_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
   9 #include "ebb.h"
  10
  11
  12 /*
  13  * Test that PMC5 & 6 are frozen (ie. don't overflow) when they are not being
  14  * used. Tests the MMCR0_FC56 logic in the kernel.
  15  */
  16
  17 static int pmc56_overflowed;
  18
  19 static void ebb_callee(void)
  20 {
  21         uint64_t val;
  22
  23         val = mfspr(SPRN_BESCR);
  24         if (!(val & BESCR_PMEO)) {
  25                 ebb_state.stats.spurious++;
  26                 goto out;
  27         }
  28
  29         ebb_state.stats.ebb_count++;
  30         count_pmc(2, sample_period);
  31
  32         val = mfspr(SPRN_PMC5);
  33         if (val >= COUNTER_OVERFLOW)
  34                 pmc56_overflowed++;
  35
  36         count_pmc(5, COUNTER_OVERFLOW);
  37
  38         val = mfspr(SPRN_PMC6);
  39         if (val >= COUNTER_OVERFLOW)
  40                 pmc56_overflowed++;
  41
  42         count_pmc(6, COUNTER_OVERFLOW);
  43
  44 out:
  45         reset_ebb();
  46 }
  47
  48 int pmc56_overflow(void)
  49 {
  50         struct event event;
  51
  52         /* Use PMC2 so we set PMCjCE, which enables PMC5/6 */
  53         event_init(&event, 0x2001e);
  54         event_leader_ebb_init(&event);
  55
  56         event.attr.exclude_kernel = 1;
  57         event.attr.exclude_hv = 1;
  58         event.attr.exclude_idle = 1;
  59
  60         FAIL_IF(event_open(&event));
  61
  62         setup_ebb_handler(ebb_callee);
  63         ebb_global_enable();
  64
  65         FAIL_IF(ebb_event_enable(&event));
  66
  67         mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
  68         mtspr(SPRN_PMC5, 0);
  69         mtspr(SPRN_PMC6, 0);
  70
  71         while (ebb_state.stats.ebb_count < 10)
  72                 FAIL_IF(core_busy_loop());
  73
  74         ebb_global_disable();
  75         ebb_freeze_pmcs();
  76
  77         count_pmc(2, sample_period);
  78
  79         dump_ebb_state();
  80
  81         printf("PMC5/6 overflow %d\n", pmc56_overflowed);
  82
  83         event_close(&event);
  84
  85         FAIL_IF(ebb_state.stats.ebb_count == 0 || pmc56_overflowed != 0);
  86
  87         return 0;
  88 }
  89
  90 int main(void)
  91 {
  92         return test_harness(pmc56_overflow, "pmc56_overflow");
  93 }