Commit 11bbc524 authored by Athira Rajeev's avatar Athira Rajeev Committed by Michael Ellerman
Browse files

selftests/powerpc/pmu: Add selftest to check PERF_SAMPLE_REGS_INTR option will... 


selftests/powerpc/pmu: Add selftest to check PERF_SAMPLE_REGS_INTR option will not crash on any platforms

With sampling, --intr-regs option is used for capturing
interrupt regs. When --intr-regs option is used, PMU code
uses is_sier_available() function which uses PMU flags in
the code. In environment where platform specific PMU is
not registered, PMU flags is not defined. A fix was added
in kernel to address crash while accessing is_sier_available()
function when pmu is not set. commit f75e7d73 ("powerpc/perf:
Fix crash with is_sier_available when pmu is not set").

Add perf sampling test to exercise this code and make sure
enabling intr_regs shouldn't crash in any platform. Testcase
uses software event cycles since software event will work even
in cases without PMU.

Signed-off-by: default avatarAthira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-12-atrajeev@linux.vnet.ibm.com
parent 2ac05f8f

tools/testing/selftests/powerpc/pmu/sampling_tests/Makefile

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@@ -6,7 +6,7 @@ TEST_GEN_PROGS := mmcr0_exceptionbits_test mmcr0_cc56run_test mmcr0_pmccext_test 
		   mmcr1_comb_test mmcr2_l2l3_test mmcr2_fcs_fch_test \

		   mmcr3_src_test mmcra_thresh_marked_sample_test mmcra_thresh_cmp_test \

		   mmcra_bhrb_ind_call_test mmcra_bhrb_any_test mmcra_bhrb_cond_test \

		   mmcra_bhrb_disable_test bhrb_no_crash_wo_pmu_test

		   mmcra_bhrb_disable_test bhrb_no_crash_wo_pmu_test intr_regs_no_crash_wo_pmu_test



top_srcdir = ../../../../../..

include ../../../lib.mk

tools/testing/selftests/powerpc/pmu/sampling_tests/intr_regs_no_crash_wo_pmu_test.c

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// SPDX-License-Identifier: GPL-2.0-only

/*

 * Copyright 2022, Athira Rajeev, IBM Corp.

 */



#include <stdio.h>

#include <stdlib.h>



#include "../event.h"

#include "misc.h"

#include "utils.h"



/*

 * A perf sampling test for making sure

 * sampling with -intr-regs doesn't crash

 * in any environment, say:

 *  - With generic compat PMU

 *  - without any PMU registered

 *  - With platform specific PMU.

 *  A fix for crash with intr_regs was

 *  addressed in commit: f75e7d73bdf7 in kernel.

 *

 * This testcase exercises this code path by doing

 * intr_regs using software event. Software event is

 * used since s/w event will work even in platform

 * without PMU.

 */

static int intr_regs_no_crash_wo_pmu_test(void)

{

	struct event event;



	/*

	 * Init the event for the sampling test.

	 * This uses software event which works on

	 * any platform.

	 */

	event_init_opts(&event, 0, PERF_TYPE_SOFTWARE, "cycles");



	event.attr.sample_period = 1000;

	event.attr.sample_type = PERF_SAMPLE_REGS_INTR;

	event.attr.disabled = 1;



	/*

	 * Return code of event_open is not considered

	 * since test just expects no crash from using

	 * PERF_SAMPLE_REGS_INTR.

	 */

	event_open(&event);



	event_close(&event);

	return 0;

}



int main(void)

{

	return test_harness(intr_regs_no_crash_wo_pmu_test, "intr_regs_no_crash_wo_pmu_test");

}