pmu/ebb/pmc56_overflow_test.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright 2014, Michael Ellerman, IBM Corp.
0004  */
0005
0006 #include <stdio.h>
0007 #include <stdlib.h>
0008
0009 #include "ebb.h"
0010
0011
0012 /*
0013  * Test that PMC5 & 6 are frozen (ie. don't overflow) when they are not being
0014  * used. Tests the MMCR0_FC56 logic in the kernel.
0015  */
0016
0017 static int pmc56_overflowed;
0018
0019 static void ebb_callee(void)
0020 {
0021     uint64_t val;
0022
0023     val = mfspr(SPRN_BESCR);
0024     if (!(val & BESCR_PMEO)) {
0025         ebb_state.stats.spurious++;
0026         goto out;
0027     }
0028
0029     ebb_state.stats.ebb_count++;
0030     count_pmc(2, sample_period);
0031
0032     val = mfspr(SPRN_PMC5);
0033     if (val >= COUNTER_OVERFLOW)
0034         pmc56_overflowed++;
0035
0036     count_pmc(5, COUNTER_OVERFLOW);
0037
0038     val = mfspr(SPRN_PMC6);
0039     if (val >= COUNTER_OVERFLOW)
0040         pmc56_overflowed++;
0041
0042     count_pmc(6, COUNTER_OVERFLOW);
0043
0044 out:
0045     reset_ebb();
0046 }
0047
0048 int pmc56_overflow(void)
0049 {
0050     struct event event;
0051
0052     SKIP_IF(!ebb_is_supported());
0053
0054     /* Use PMC2 so we set PMCjCE, which enables PMC5/6 */
0055     event_init(&event, 0x2001e);
0056     event_leader_ebb_init(&event);
0057
0058     event.attr.exclude_kernel = 1;
0059     event.attr.exclude_hv = 1;
0060     event.attr.exclude_idle = 1;
0061
0062     FAIL_IF(event_open(&event));
0063
0064     setup_ebb_handler(ebb_callee);
0065     ebb_global_enable();
0066
0067     FAIL_IF(ebb_event_enable(&event));
0068
0069     mtspr(SPRN_PMC2, pmc_sample_period(sample_period));
0070     mtspr(SPRN_PMC5, 0);
0071     mtspr(SPRN_PMC6, 0);
0072
0073     while (ebb_state.stats.ebb_count < 10)
0074         FAIL_IF(core_busy_loop());
0075
0076     ebb_global_disable();
0077     ebb_freeze_pmcs();
0078
0079     dump_ebb_state();
0080
0081     printf("PMC5/6 overflow %d\n", pmc56_overflowed);
0082
0083     event_close(&event);
0084
0085     FAIL_IF(ebb_state.stats.ebb_count == 0 || pmc56_overflowed != 0);
0086
0087     return 0;
0088 }
0089
0090 int main(void)
0091 {
0092     return test_harness(pmc56_overflow, "pmc56_overflow");
0093 }