linux-kernel - [RFC PATCH 35/36] arm_mpam: Add kunit test for bitmap reset

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Message-Id: <20250711183648.30766-36-james.morse@arm.com>
Date: Fri, 11 Jul 2025 18:36:47 +0000
From: James Morse <james.morse@....com>
To: linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Cc: Rob Herring <robh@...nel.org>,
	Ben Horgan <ben.horgan@....com>,
	Rohit Mathew <rohit.mathew@....com>,
	Shanker Donthineni <sdonthineni@...dia.com>,
	Zeng Heng <zengheng4@...wei.com>,
	Lecopzer Chen <lecopzerc@...dia.com>,
	Carl Worth <carl@...amperecomputing.com>,
	shameerali.kolothum.thodi@...wei.com,
	D Scott Phillips OS <scott@...amperecomputing.com>,
	lcherian@...vell.com,
	bobo.shaobowang@...wei.com,
	tan.shaopeng@...itsu.com,
	baolin.wang@...ux.alibaba.com,
	Jamie Iles <quic_jiles@...cinc.com>,
	Xin Hao <xhao@...ux.alibaba.com>,
	peternewman@...gle.com,
	dfustini@...libre.com,
	amitsinght@...vell.com,
	David Hildenbrand <david@...hat.com>,
	Rex Nie <rex.nie@...uarmicro.com>,
	Dave Martin <dave.martin@....com>,
	Koba Ko <kobak@...dia.com>,
	James Morse <james.morse@....com>,
	Jonathan Cameron <Jonathan.Cameron@...wei.com>
Subject: [RFC PATCH 35/36] arm_mpam: Add kunit test for bitmap reset

The bitmap reset code has been a source of bugs. Add a unit test.

This currently has to be built in, as the rest of the driver is
builtin.

Suggested-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Signed-off-by: James Morse <james.morse@....com>
---
 drivers/platform/arm64/mpam/Kconfig           | 13 ++++
 drivers/platform/arm64/mpam/mpam_devices.c    |  4 ++
 .../platform/arm64/mpam/test_mpam_devices.c   | 68 +++++++++++++++++++
 3 files changed, 85 insertions(+)
 create mode 100644 drivers/platform/arm64/mpam/test_mpam_devices.c

diff --git a/drivers/platform/arm64/mpam/Kconfig b/drivers/platform/arm64/mpam/Kconfig
index b63495d7da87..861e4b946ddc 100644
--- a/drivers/platform/arm64/mpam/Kconfig
+++ b/drivers/platform/arm64/mpam/Kconfig
@@ -4,7 +4,20 @@ config ARM_CPU_RESCTRL
 	bool
 	depends on ARM64
 
+menu "ARM64 MPAM driver options"
+
 config ARM64_MPAM_DRIVER_DEBUG
 	bool "Enable debug messages from the MPAM driver."
 	help
 	  Say yes here to enable debug messages from the MPAM driver.
+
+config MPAM_KUNIT_TEST
+	bool "KUnit tests for MPAM driver " if !KUNIT_ALL_TESTS
+	depends on KUNIT=y
+	default KUNIT_ALL_TESTS
+	help
+	  Enable this option to run tests in the MPAM driver.
+
+	  If unsure, say N.
+
+endmenu
diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index 470a3709670e..a7f301b0da84 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -2904,3 +2904,7 @@ static int __init mpam_msc_driver_init(void)
 }
 /* Must occur after arm64_mpam_register_cpus() from arch_initcall() */
 subsys_initcall(mpam_msc_driver_init);
+
+#ifdef CONFIG_MPAM_KUNIT_TEST
+#include "test_mpam_devices.c"
+#endif
diff --git a/drivers/platform/arm64/mpam/test_mpam_devices.c b/drivers/platform/arm64/mpam/test_mpam_devices.c
new file mode 100644
index 000000000000..8e9d6c88171c
--- /dev/null
+++ b/drivers/platform/arm64/mpam/test_mpam_devices.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2024 Arm Ltd.
+/* This file is intended to be included into mpam_devices.c */
+
+#include <kunit/test.h>
+
+static void test_mpam_reset_msc_bitmap(struct kunit *test)
+{
+	char *buf = kunit_kzalloc(test, SZ_16K, GFP_KERNEL);
+	struct mpam_msc fake_msc;
+	u32 *test_result;
+
+	if (!buf)
+		return;
+
+	fake_msc.mapped_hwpage = buf;
+	fake_msc.mapped_hwpage_sz = SZ_16K;
+	cpumask_copy(&fake_msc.accessibility, cpu_possible_mask);
+
+	mutex_init(&fake_msc.part_sel_lock);
+	mutex_lock(&fake_msc.part_sel_lock);
+
+	test_result = (u32 *)(buf + MPAMCFG_CPBM);
+
+	mpam_reset_msc_bitmap(&fake_msc, MPAMCFG_CPBM, 0);
+	KUNIT_EXPECT_EQ(test, test_result[0], 0);
+	KUNIT_EXPECT_EQ(test, test_result[1], 0);
+	test_result[0] = 0;
+	test_result[1] = 0;
+
+	mpam_reset_msc_bitmap(&fake_msc, MPAMCFG_CPBM, 1);
+	KUNIT_EXPECT_EQ(test, test_result[0], 1);
+	KUNIT_EXPECT_EQ(test, test_result[1], 0);
+	test_result[0] = 0;
+	test_result[1] = 0;
+
+	mpam_reset_msc_bitmap(&fake_msc, MPAMCFG_CPBM, 16);
+	KUNIT_EXPECT_EQ(test, test_result[0], 0xffff);
+	KUNIT_EXPECT_EQ(test, test_result[1], 0);
+	test_result[0] = 0;
+	test_result[1] = 0;
+
+	mpam_reset_msc_bitmap(&fake_msc, MPAMCFG_CPBM, 32);
+	KUNIT_EXPECT_EQ(test, test_result[0], 0xffffffff);
+	KUNIT_EXPECT_EQ(test, test_result[1], 0);
+	test_result[0] = 0;
+	test_result[1] = 0;
+
+	mpam_reset_msc_bitmap(&fake_msc, MPAMCFG_CPBM, 33);
+	KUNIT_EXPECT_EQ(test, test_result[0], 0xffffffff);
+	KUNIT_EXPECT_EQ(test, test_result[1], 1);
+	test_result[0] = 0;
+	test_result[1] = 0;
+
+	mutex_unlock(&fake_msc.part_sel_lock);
+}
+
+static struct kunit_case mpam_devices_test_cases[] = {
+	KUNIT_CASE(test_mpam_reset_msc_bitmap),
+	{}
+};
+
+static struct kunit_suite mpam_devices_test_suite = {
+	.name = "mpam_devices_test_suite",
+	.test_cases = mpam_devices_test_cases,
+};
+
+kunit_test_suites(&mpam_devices_test_suite);
-- 
2.39.5