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

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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 f75e7d73bdf7 ("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: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220610134113.62991-12-atrajeev@linux.vnet.ibm.com
This commit is contained in:
Athira Rajeev 2022-06-10 19:10:49 +05:30 committed by Michael Ellerman
parent 2ac05f8f2e
commit 11bbc52439
2 changed files with 58 additions and 1 deletions
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2
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 \ mmcr1_comb_test mmcr2_l2l3_test mmcr2_fcs_fch_test \
mmcr3_src_test mmcra_thresh_marked_sample_test mmcra_thresh_cmp_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_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 = ../../../../../.. top_srcdir = ../../../../../..
include ../../../lib.mk include ../../../lib.mk

57
tools/testing/selftests/powerpc/pmu/sampling_tests/intr_regs_no_crash_wo_pmu_test.c Normal file
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@ -0,0 +1,57 @@
// 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");
}