[kvm-unit-tests PATCH v10 1/3] arm: Add PMU test

Wei Huang
2016-11-21T20:24:53Z

From: Christopher Covington <cov@codeaurora.org>

Beginning with a simple sanity check of the control register, add
a unit test for the ARM Performance Monitors Unit (PMU).

Signed-off-by: Christopher Covington <cov@codeaurora.org>
Signed-off-by: Wei Huang <wei@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
---
arm/Makefile.common | 3 ++-
arm/pmu.c | 74 +++++++++++++++++++++++++++++++++++++++++++++++++++++
arm/unittests.cfg | 5 ++++
3 files changed, 81 insertions(+), 1 deletion(-)
create mode 100644 arm/pmu.c

diff --git a/arm/Makefile.common b/arm/Makefile.common
index f37b5c2..5da2fdd 100644
--- a/arm/Makefile.common
+++ b/arm/Makefile.common
@@ -12,7 +12,8 @@ endif
tests-common = \
$(TEST_DIR)/selftest.flat \
$(TEST_DIR)/spinlock-test.flat \
- $(TEST_DIR)/pci-test.flat
+ $(TEST_DIR)/pci-test.flat \
+ $(TEST_DIR)/pmu.flat

all: test_cases

diff --git a/arm/pmu.c b/arm/pmu.c
new file mode 100644
index 0000000..9d9c53b
--- /dev/null
+++ b/arm/pmu.c
@@ -0,0 +1,74 @@
+/*
+ * Test the ARM Performance Monitors Unit (PMU).
+ *
+ * Copyright (c) 2015-2016, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License version 2.1 and
+ * only version 2.1 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
+ * for more details.
+ */
+#include "libcflat.h"
+#include "asm/barrier.h"
+
+#define PMU_PMCR_N_SHIFT 11
+#define PMU_PMCR_N_MASK 0x1f
+#define PMU_PMCR_ID_SHIFT 16
+#define PMU_PMCR_ID_MASK 0xff
+#define PMU_PMCR_IMP_SHIFT 24
+#define PMU_PMCR_IMP_MASK 0xff
+
+#if defined(__arm__)
+static inline uint32_t pmcr_read(void)
+{
+ uint32_t ret;
+
+ asm volatile("mrc p15, 0, %0, c9, c12, 0" : "=r" (ret));
+ return ret;
+}
+#elif defined(__aarch64__)
+static inline uint32_t pmcr_read(void)
+{
+ uint32_t ret;
+
+ asm volatile("mrs %0, pmcr_el0" : "=r" (ret));
+ return ret;
+}
+#endif
+
+/*
+ * As a simple sanity check on the PMCR_EL0, ensure the implementer field isn't
+ * null. Also print out a couple other interesting fields for diagnostic
+ * purposes. For example, as of fall 2016, QEMU TCG mode doesn't implement
+ * event counters and therefore reports zero event counters, but hopefully
+ * support for at least the instructions event will be added in the future and
+ * the reported number of event counters will become nonzero.
+ */
+static bool check_pmcr(void)
+{
+ uint32_t pmcr;
+
+ pmcr = pmcr_read();
+
+ printf("PMU implementer: %c\n",
+ (pmcr >> PMU_PMCR_IMP_SHIFT) & PMU_PMCR_IMP_MASK);
+ printf("Identification code: 0x%x\n",
+ (pmcr >> PMU_PMCR_ID_SHIFT) & PMU_PMCR_ID_MASK);
+ printf("Event counters: %d\n",
+ (pmcr >> PMU_PMCR_N_SHIFT) & PMU_PMCR_N_MASK);
+
+ return ((pmcr >> PMU_PMCR_IMP_SHIFT) & PMU_PMCR_IMP_MASK) != 0;
+}
+
+int main(void)
+{
+ report_prefix_push("pmu");
+
+ report("Control register", check_pmcr());
+
+ return report_summary();
+}
diff --git a/arm/unittests.cfg b/arm/unittests.cfg
index ae32a42..816f494 100644
--- a/arm/unittests.cfg
+++ b/arm/unittests.cfg
@@ -58,3 +58,8 @@ groups = selftest
[pci-test]
file = pci-test.flat
groups = pci
+
+# Test PMU support
+[pmu]
+file = pmu.flat
+groups = pmu
--
1.8.3.1