LXR linux/tools/testing/selftests/powerpc/pmu/ebb/pmc56_overflow

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Copyright 2014, Michael Ellerman, IBM Corp.
   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
  17static int pmc56_overflowed;
  18
  19static 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
  44out:
  45        reset_ebb();
  46}
  47
  48int pmc56_overflow(void)
  49{
  50        struct event event;
  51
  52        SKIP_IF(!ebb_is_supported());
  53
  54        /* Use PMC2 so we set PMCjCE, which enables PMC5/6 */
  55        event_init(&event, 0x2001e);
  56        event_leader_ebb_init(&event);
  57
  58        event.attr.exclude_kernel = 1;
  59        event.attr.exclude_hv = 1;
  60        event.attr.exclude_idle = 1;
  61
  62        FAIL_IF(event_open(&event));
  63
  64        setup_ebb_handler(ebb_callee);
  65        ebb_global_enable();
  66
  67        FAIL_IF(ebb_event_enable(&event));
  68
  69        mtspr(SPRN_PMC2, pmc_sample_period(sample_period));
  70        mtspr(SPRN_PMC5, 0);
  71        mtspr(SPRN_PMC6, 0);
  72
  73        while (ebb_state.stats.ebb_count < 10)
  74                FAIL_IF(core_busy_loop());
  75
  76        ebb_global_disable();
  77        ebb_freeze_pmcs();
  78
  79        count_pmc(2, sample_period);
  80
  81        dump_ebb_state();
  82
  83        printf("PMC5/6 overflow %d\n", pmc56_overflowed);
  84
  85        event_close(&event);
  86
  87        FAIL_IF(ebb_state.stats.ebb_count == 0 || pmc56_overflowed != 0);
  88
  89        return 0;
  90}
  91
  92int main(void)
  93{
  94        return test_harness(pmc56_overflow, "pmc56_overflow");
  95}
  96