---
Changes from v5:
* Incorporate review comments.
* Fix arm_cspmu_impl_match_get not returning NULL if no matching impl.
* Fix impl_match.module may reset when registering PMU.
* Maintain backend module ref count until PMU registration is done.
Thanks to Will, Suzuki, and Robin for the feedback.
v5: https://lore.kernel.org/linux-arm-kernel/20230705104745.52255-1-bwicaksono@xxxxxxxxxx/T/#u
Changes from v4:
* Fix warning reported by kernel test robot
v4: https://lore.kernel.org/linux-arm-kernel/20230620041438.32514-1-bwicaksono@xxxxxxxxxx/T/#u
Changes from v3:
* Move impl registration module back to main driver module.
* Rebase from will (for-next/perf)
Thanks to Robin for the feedback.
v3: https://lore.kernel.org/linux-arm-kernel/20230505005956.22837-1-bwicaksono@xxxxxxxxxx/T/#u
Changes from v2:
* Move sysfs_event/format_show definition to arm_cspmu.h and move impl
registration API definition to a separate module so main driver and vendor
module are independent.
* The registration API now just sets the impl_init_ops callback, no reprobe.
* Add PMIIDR table that maps to the vendor module name. During device probe,
main driver requests the vendor module if PMIIDR is matching.
* Keeping the name of the main driver module as arm_cspmu_module.
Thanks to Robin and Suzuki for the feedback.
v2: https://lore.kernel.org/linux-arm-kernel/20230418062030.45620-1-bwicaksono@xxxxxxxxxx/T/#u
Changes from v1:
* Added separate Kconfig entry for nvidia backend
* Added lock to protect accesses to the lists
* Added support for matching subset devices from a vendor
* Added state tracking to avoid reprobe when a device is in use
Thanks to Suzuki for the feedback.
v1: https://lore.kernel.org/linux-arm-kernel/20230403163905.20354-1-bwicaksono@xxxxxxxxxx/T/#u
---
drivers/perf/arm_cspmu/Kconfig | 9 +-
drivers/perf/arm_cspmu/Makefile | 6 +-
drivers/perf/arm_cspmu/arm_cspmu.c | 168 ++++++++++++++++++++------
drivers/perf/arm_cspmu/arm_cspmu.h | 25 +++-
drivers/perf/arm_cspmu/nvidia_cspmu.c | 34 +++++-
drivers/perf/arm_cspmu/nvidia_cspmu.h | 17 ---
6 files changed, 199 insertions(+), 60 deletions(-)
delete mode 100644 drivers/perf/arm_cspmu/nvidia_cspmu.h
diff --git a/drivers/perf/arm_cspmu/Kconfig b/drivers/perf/arm_cspmu/Kconfig
index 25d25ded0983..d5f787d22234 100644
--- a/drivers/perf/arm_cspmu/Kconfig
+++ b/drivers/perf/arm_cspmu/Kconfig
@@ -1,6 +1,6 @@
# SPDX-License-Identifier: GPL-2.0
#
-# Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
config ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU
tristate "ARM Coresight Architecture PMU"
@@ -10,3 +10,10 @@ config ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU
based on ARM CoreSight PMU architecture. Note that this PMU
architecture does not have relationship with the ARM CoreSight
Self-Hosted Tracing.
+
+config NVIDIA_CORESIGHT_PMU_ARCH_SYSTEM_PMU
+ tristate "NVIDIA Coresight Architecture PMU"
+ depends on ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU
+ help
+ Provides NVIDIA specific attributes for performance monitoring unit
+ (PMU) devices based on ARM CoreSight PMU architecture.
diff --git a/drivers/perf/arm_cspmu/Makefile b/drivers/perf/arm_cspmu/Makefile
index fedb17df982d..0309d2ff264a 100644
--- a/drivers/perf/arm_cspmu/Makefile
+++ b/drivers/perf/arm_cspmu/Makefile
@@ -1,6 +1,8 @@
-# Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+# Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
#
# SPDX-License-Identifier: GPL-2.0
obj-$(CONFIG_ARM_CORESIGHT_PMU_ARCH_SYSTEM_PMU) += arm_cspmu_module.o
-arm_cspmu_module-y := arm_cspmu.o nvidia_cspmu.o
+arm_cspmu_module-y := arm_cspmu.o
+
+obj-$(CONFIG_NVIDIA_CORESIGHT_PMU_ARCH_SYSTEM_PMU) += nvidia_cspmu.o
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.c b/drivers/perf/arm_cspmu/arm_cspmu.c
index e2b7827c4563..c59f1e5a35a3 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.c
+++ b/drivers/perf/arm_cspmu/arm_cspmu.c
@@ -16,7 +16,7 @@
* The user should refer to the vendor technical documentation to get details
* about the supported events.
*
- * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
*
*/
@@ -26,11 +26,11 @@
#include <linux/interrupt.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/module.h>
+#include <linux/mutex.h>
#include <linux/perf_event.h>
#include <linux/platform_device.h>
#include "arm_cspmu.h"
-#include "nvidia_cspmu.h"
#define PMUNAME "arm_cspmu"
#define DRVNAME "arm-cs-arch-pmu"
@@ -112,11 +112,10 @@
*/
#define HILOHI_MAX_POLL 1000
-/* JEDEC-assigned JEP106 identification code */
-#define ARM_CSPMU_IMPL_ID_NVIDIA 0x36B
-
static unsigned long arm_cspmu_cpuhp_state;
+static DEFINE_MUTEX(arm_cspmu_lock);
+
static struct acpi_apmt_node *arm_cspmu_apmt_node(struct device *dev)
{
return *(struct acpi_apmt_node **)dev_get_platdata(dev);
@@ -373,27 +372,37 @@ static struct attribute_group arm_cspmu_cpumask_attr_group = {
.attrs = arm_cspmu_cpumask_attrs,
};
-struct impl_match {
- u32 pmiidr;
- u32 mask;
- int (*impl_init_ops)(struct arm_cspmu *cspmu);
-};
-
-static const struct impl_match impl_match[] = {
+static struct arm_cspmu_impl_match impl_match[] = {
{
- .pmiidr = ARM_CSPMU_IMPL_ID_NVIDIA,
- .mask = ARM_CSPMU_PMIIDR_IMPLEMENTER,
- .impl_init_ops = nv_cspmu_init_ops
+ .module_name = "nvidia_cspmu",
+ .pmiidr_val = ARM_CSPMU_IMPL_ID_NVIDIA,
+ .pmiidr_mask = ARM_CSPMU_PMIIDR_IMPLEMENTER,
+ .module = NULL,
+ .impl_init_ops = NULL,
},
- {}
+ {0}
};
+static struct arm_cspmu_impl_match *arm_cspmu_impl_match_get(u32 pmiidr)
+{
+ struct arm_cspmu_impl_match *match = impl_match;
+
+ for (; match->pmiidr_val; match++) {
+ u32 mask = match->pmiidr_mask;
+
+ if ((match->pmiidr_val & mask) == (pmiidr & mask))
+ return match;
+ }
+
+ return NULL;
+}
+
static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
{
- int ret;
+ int ret = 0;
struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
struct acpi_apmt_node *apmt_node = arm_cspmu_apmt_node(cspmu->dev);
- const struct impl_match *match = impl_match;
+ struct arm_cspmu_impl_match *match;
/*
* Get PMU implementer and product id from APMT node.
@@ -405,17 +414,36 @@ static int arm_cspmu_init_impl_ops(struct arm_cspmu *cspmu)
readl(cspmu->base0 + PMIIDR);
/* Find implementer specific attribute ops. */
- for (; match->pmiidr; match++) {
- const u32 mask = match->mask;
+ match = arm_cspmu_impl_match_get(cspmu->impl.pmiidr);
+
+ /* Load implementer module and initialize the callbacks. */
+ if (match) {
+ mutex_lock(&arm_cspmu_lock);
+
+ if (match->impl_init_ops) {
+ /* Prevent unload until PMU registration is done. */
+ if (try_module_get(match->module)) {
+ cspmu->impl.module = match->module;
+ cspmu->impl.match = match;
+ ret = match->impl_init_ops(cspmu);
+ if (ret)
+ module_put(match->module);
+ } else {
+ WARN(1, "arm_cspmu failed to get module: %s\n",
+ match->module_name);
+ ret = -EINVAL;
+ }
+ } else {
+ request_module_nowait(match->module_name);
+ ret = -EPROBE_DEFER;
+ }
- if ((match->pmiidr & mask) == (cspmu->impl.pmiidr & mask)) {
- ret = match->impl_init_ops(cspmu);
- if (ret)
- return ret;
+ mutex_unlock(&arm_cspmu_lock);
- break;
- }
- }
+ if (ret)
+ return ret;
+ } else
+ cspmu->impl.module = THIS_MODULE;
/* Use default callbacks if implementer doesn't provide one. */
CHECK_DEFAULT_IMPL_OPS(impl_ops, get_event_attrs);
@@ -478,11 +506,6 @@ arm_cspmu_alloc_attr_group(struct arm_cspmu *cspmu)
struct attribute_group **attr_groups = NULL;
struct device *dev = cspmu->dev;
const struct arm_cspmu_impl_ops *impl_ops = &cspmu->impl.ops;
- int ret;
-
- ret = arm_cspmu_init_impl_ops(cspmu);
- if (ret)
- return NULL;
cspmu->identifier = impl_ops->get_identifier(cspmu);
cspmu->name = impl_ops->get_name(cspmu);
@@ -1149,7 +1172,7 @@ static int arm_cspmu_register_pmu(struct arm_cspmu *cspmu)
cspmu->pmu = (struct pmu){
.task_ctx_nr = perf_invalid_context,
- .module = THIS_MODULE,
+ .module = cspmu->impl.module,
.pmu_enable = arm_cspmu_enable,
.pmu_disable = arm_cspmu_disable,
.event_init = arm_cspmu_event_init,
@@ -1196,11 +1219,17 @@ static int arm_cspmu_device_probe(struct platform_device *pdev)
if (ret)
return ret;
- ret = arm_cspmu_register_pmu(cspmu);
+ ret = arm_cspmu_init_impl_ops(cspmu);
if (ret)
return ret;
- return 0;
+ ret = arm_cspmu_register_pmu(cspmu);
+
+ /* Matches arm_cspmu_init_impl_ops() above. */
+ if (cspmu->impl.module != THIS_MODULE)
+ module_put(cspmu->impl.module);
+
+ return ret;
}
static int arm_cspmu_device_remove(struct platform_device *pdev)
@@ -1300,6 +1329,75 @@ static void __exit arm_cspmu_exit(void)
cpuhp_remove_multi_state(arm_cspmu_cpuhp_state);
}
+int arm_cspmu_impl_register(const struct arm_cspmu_impl_match *impl_match)
+{
+ struct arm_cspmu_impl_match *match;
+ int ret = 0;
+
+ match = arm_cspmu_impl_match_get(impl_match->pmiidr_val);
+
+ if (match) {
+ mutex_lock(&arm_cspmu_lock);
+
+ if (!match->impl_init_ops) {
+ match->module = impl_match->module;
+ match->impl_init_ops = impl_match->impl_init_ops;
+ } else {
+ /* Broken match table may contain non-unique entries */
+ WARN(1, "arm_cspmu backend already registered for module: %s, pmiidr: 0x%x, mask: 0x%x\n",
+ match->module_name,
+ match->pmiidr_val,
+ match->pmiidr_mask);
+
+ ret = -EINVAL;
+ }
+
+ mutex_unlock(&arm_cspmu_lock);
+
+ if (!ret)
+ ret = driver_attach(&arm_cspmu_driver.driver);
+ } else {
+ pr_err("arm_cspmu reg failed, unable to find a match for pmiidr: 0x%x\n",
+ impl_match->pmiidr_val);
+
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(arm_cspmu_impl_register);
+
+static int arm_cspmu_match_device(struct device *dev, const void *match)
+{
+ struct arm_cspmu *cspmu = platform_get_drvdata(to_platform_device(dev));
+
+ return (cspmu && cspmu->impl.match == match) ? 1 : 0;
+}
+
+void arm_cspmu_impl_unregister(const struct arm_cspmu_impl_match *impl_match)
+{
+ struct device *dev;
+ struct arm_cspmu_impl_match *match;
+
+ match = arm_cspmu_impl_match_get(impl_match->pmiidr_val);
+
+ if (WARN_ON(!match))
+ return;
+
+ /* Unbind the driver from all matching backend devices. */
+ while ((dev = driver_find_device(&arm_cspmu_driver.driver, NULL,
+ match, arm_cspmu_match_device)))
+ device_release_driver(dev);
+
+ mutex_lock(&arm_cspmu_lock);
+
+ match->module = NULL;
+ match->impl_init_ops = NULL;
+
+ mutex_unlock(&arm_cspmu_lock);
+}
+EXPORT_SYMBOL_GPL(arm_cspmu_impl_unregister);
+
module_init(arm_cspmu_init);
module_exit(arm_cspmu_exit);
diff --git a/drivers/perf/arm_cspmu/arm_cspmu.h b/drivers/perf/arm_cspmu/arm_cspmu.h
index 83df53d1c132..7936a90ded7f 100644
--- a/drivers/perf/arm_cspmu/arm_cspmu.h
+++ b/drivers/perf/arm_cspmu/arm_cspmu.h
@@ -1,7 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0
*
* ARM CoreSight Architecture PMU driver.
- * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
*
*/
@@ -69,6 +69,9 @@
#define ARM_CSPMU_PMIIDR_IMPLEMENTER GENMASK(11, 0)
#define ARM_CSPMU_PMIIDR_PRODUCTID GENMASK(31, 20)
+/* JEDEC-assigned JEP106 identification code */
+#define ARM_CSPMU_IMPL_ID_NVIDIA 0x36B
+
struct arm_cspmu;
/* This tracks the events assigned to each counter in the PMU. */
@@ -106,9 +109,23 @@ struct arm_cspmu_impl_ops {
struct attribute *attr, int unused);
};
+/* Vendor/implementer registration parameter. */
+struct arm_cspmu_impl_match {
+ /* Backend module. */
+ struct module *module;
+ const char *module_name;
+ /* PMIIDR value/mask. */
+ u32 pmiidr_val;
+ u32 pmiidr_mask;
+ /* Callback to vendor backend to init arm_cspmu_impl::ops. */
+ int (*impl_init_ops)(struct arm_cspmu *cspmu);
+};
+
/* Vendor/implementer descriptor. */
struct arm_cspmu_impl {
u32 pmiidr;
+ struct module *module;
+ struct arm_cspmu_impl_match *match;
struct arm_cspmu_impl_ops ops;
void *ctx;
};
@@ -147,4 +164,10 @@ ssize_t arm_cspmu_sysfs_format_show(struct device *dev,
struct device_attribute *attr,
char *buf);
+/* Register vendor backend. */
+int arm_cspmu_impl_register(const struct arm_cspmu_impl_match *impl_match);
+
+/* Unregister vendor backend. */
+void arm_cspmu_impl_unregister(const struct arm_cspmu_impl_match *impl_match);
+
#endif /* __ARM_CSPMU_H__ */
diff --git a/drivers/perf/arm_cspmu/nvidia_cspmu.c b/drivers/perf/arm_cspmu/nvidia_cspmu.c
index 72ef80caa3c8..0382b702f092 100644
--- a/drivers/perf/arm_cspmu/nvidia_cspmu.c
+++ b/drivers/perf/arm_cspmu/nvidia_cspmu.c
@@ -1,14 +1,15 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
+ * Copyright (c) 2022-2023, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
*
*/
/* Support for NVIDIA specific attributes. */
+#include <linux/module.h>
#include <linux/topology.h>
-#include "nvidia_cspmu.h"
+#include "arm_cspmu.h"
#define NV_PCIE_PORT_COUNT 10ULL
#define NV_PCIE_FILTER_ID_MASK GENMASK_ULL(NV_PCIE_PORT_COUNT - 1, 0)
@@ -351,7 +352,7 @@ static char *nv_cspmu_format_name(const struct arm_cspmu *cspmu,
return name;
}
-int nv_cspmu_init_ops(struct arm_cspmu *cspmu)
+static int nv_cspmu_init_ops(struct arm_cspmu *cspmu)
{
u32 prodid;
struct nv_cspmu_ctx *ctx;
@@ -395,6 +396,31 @@ int nv_cspmu_init_ops(struct arm_cspmu *cspmu)
return 0;
}
-EXPORT_SYMBOL_GPL(nv_cspmu_init_ops);
+
+/* Match all NVIDIA Coresight PMU devices */
+static const struct arm_cspmu_impl_match nv_cspmu_param = {
+ .pmiidr_val = ARM_CSPMU_IMPL_ID_NVIDIA,
+ .module = THIS_MODULE,
+ .impl_init_ops = nv_cspmu_init_ops
+};
+
+static int __init nvidia_cspmu_init(void)
+{
+ int ret;
+
+ ret = arm_cspmu_impl_register(&nv_cspmu_param);
+ if (ret)
+ pr_err("nvidia_cspmu backend registration error: %d\n", ret);
+
+ return ret;
+}
+
+static void __exit nvidia_cspmu_exit(void)
+{
+ arm_cspmu_impl_unregister(&nv_cspmu_param);
+}
+
+module_init(nvidia_cspmu_init);
+module_exit(nvidia_cspmu_exit);
MODULE_LICENSE("GPL v2");
diff --git a/drivers/perf/arm_cspmu/nvidia_cspmu.h b/drivers/perf/arm_cspmu/nvidia_cspmu.h
deleted file mode 100644
index 71e18f0dc50b..000000000000
--- a/drivers/perf/arm_cspmu/nvidia_cspmu.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0
- *
- * Copyright (c) 2022, NVIDIA CORPORATION & AFFILIATES. All rights reserved.
- *
- */
-
-/* Support for NVIDIA specific attributes. */
-
-#ifndef __NVIDIA_CSPMU_H__
-#define __NVIDIA_CSPMU_H__
-
-#include "arm_cspmu.h"
-
-/* Allocate NVIDIA descriptor. */
-int nv_cspmu_init_ops(struct arm_cspmu *cspmu);
-
-#endif /* __NVIDIA_CSPMU_H__ */
base-commit: ea8d1c062a0e876e999e4f347daeb598d5e677ab
--
2.17.1
