arm64/mpam: Add mpam driver discovery phase and kbuild boiler plate

hulk inclusion
category: feature
feature: ARM MPAM support
bugzilla: 48265
CVE: NA

--------------------------------

Components with MPAM controls (or monitors) could be placed anywhere
in the system, each with their own set MMIO configuration area.

Firmware tables tell us the components position in the topology and
location of its MMIO configuration area, as well as which logical
component this corresponds with.

For now, we are only interested in the well-known caches, e.g. L2.

To reduce the number of times we have to schedule work on another CPU,
we collect all the information from the firmware tables between
mpam_discovery_start() and mpam_discovery_complete().

If the code parseing firmware tables concludes it can't continue, it
can call mpam_discovery_failed() to free the allocated memory.

[Wang ShaoBo: few version adaptation changes]
Signed-off-by: NJames Morse <james.morse@arm.com>
Link: http://www.linux-arm.org/git?p=linux-jm.git;a=patch;h=ba79c6b4021fb13f395ea033bf950894f1c494fdSigned-off-by: NWang ShaoBo <bobo.shaobowang@huawei.com>
Reviewed-by: NXiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: NCheng Jian <cj.chengjian@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm64/kernel/mpam/Makefile

 # SPDX-License-Identifier: GPL-2.0
 obj-$(CONFIG_MPAM)  += mpam_resctrl.o mpam_mon.o \
-					mpam_ctrlmon.o
+					mpam_ctrlmon.o mpam_device.o

arch/arm64/kernel/mpam/mpam_device.c

+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Common code for ARM v8 MPAM
+ *
+ * Copyright (C) 2020-2021 Huawei Technologies Co., Ltd
+ *
+ * Author: Wang Shaobo <bobo.shaobowang@huawei.com>
+ *
+ * Code was partially borrowed from http://www.linux-arm.org/
+ * git?p=linux-jm.git;a=shortlog;h=refs/heads/mpam/snapshot/may.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * More information about MPAM be found in the Arm Architecture Reference
+ * Manual.
+ *
+ * https://static.docs.arm.com/ddi0598/a/DDI0598_MPAM_supp_armv8a.pdf
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/io.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#include "mpam_device.h"
+
+/*
+ * During discovery this lock protects writers to class, components and devices.
+ * Once all devices are successfully probed, the system_supports_mpam() static
+ * key is enabled, and these lists become read only.
+ */
+static DEFINE_MUTEX(mpam_devices_lock);
+
+/* Devices are MSCs */
+static LIST_HEAD(mpam_all_devices);
+
+/* Classes are the set of MSCs that make up components of the same type. */
+LIST_HEAD(mpam_classes);
+
+static struct mpam_device * __init
+mpam_device_alloc(struct mpam_component *comp)
+{
+	struct mpam_device *dev;
+
+	lockdep_assert_held(&mpam_devices_lock);
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	spin_lock_init(&dev->lock);
+	INIT_LIST_HEAD(&dev->comp_list);
+	INIT_LIST_HEAD(&dev->glbl_list);
+
+	dev->comp = comp;
+	list_add(&dev->comp_list, &comp->devices);
+	list_add(&dev->glbl_list, &mpam_all_devices);
+
+	return dev;
+}
+
+static void mpam_devices_destroy(struct mpam_component *comp)
+{
+	struct mpam_device *dev, *tmp;
+
+	lockdep_assert_held(&mpam_devices_lock);
+
+	list_for_each_entry_safe(dev, tmp, &comp->devices, comp_list) {
+		list_del(&dev->comp_list);
+		list_del(&dev->glbl_list);
+		kfree(dev);
+	}
+}
+
+static struct mpam_component * __init mpam_component_alloc(int id)
+{
+	struct mpam_component *comp;
+
+	comp = kzalloc(sizeof(*comp), GFP_KERNEL);
+	if (!comp)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&comp->devices);
+	INIT_LIST_HEAD(&comp->class_list);
+
+	comp->comp_id = id;
+
+	return comp;
+}
+
+struct mpam_component *mpam_component_get(struct mpam_class *class, int id,
+						bool alloc)
+{
+	struct mpam_component *comp;
+
+	list_for_each_entry(comp, &class->components, class_list) {
+		if (comp->comp_id == id)
+			return comp;
+	}
+
+	if (!alloc)
+		return ERR_PTR(-ENOENT);
+
+	comp = mpam_component_alloc(id);
+	if (IS_ERR(comp))
+		return comp;
+
+	list_add(&comp->class_list, &class->components);
+
+	return comp;
+}
+
+static struct mpam_class * __init mpam_class_alloc(u8 level_idx,
+			enum mpam_class_types type)
+{
+	struct mpam_class *class;
+
+	lockdep_assert_held(&mpam_devices_lock);
+
+	class = kzalloc(sizeof(*class), GFP_KERNEL);
+	if (!class)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&class->components);
+	INIT_LIST_HEAD(&class->classes_list);
+
+	mutex_init(&class->lock);
+
+	class->level = level_idx;
+	class->type = type;
+
+	list_add(&class->classes_list, &mpam_classes);
+
+	return class;
+}
+
+/* free all components and devices of this class */
+static void mpam_class_destroy(struct mpam_class *class)
+{
+	struct mpam_component *comp, *tmp;
+
+	lockdep_assert_held(&mpam_devices_lock);
+
+	list_for_each_entry_safe(comp, tmp, &class->components, class_list) {
+		mpam_devices_destroy(comp);
+		list_del(&comp->class_list);
+		kfree(comp);
+	}
+}
+
+static struct mpam_class * __init mpam_class_get(u8 level_idx,
+						enum mpam_class_types type,
+						bool alloc)
+{
+	bool found = false;
+	struct mpam_class *class;
+
+	lockdep_assert_held(&mpam_devices_lock);
+
+	list_for_each_entry(class, &mpam_classes, classes_list) {
+		if (class->type == type && class->level == level_idx) {
+			found = true;
+			break;
+		}
+	}
+
+	if (found)
+		return class;
+
+	if (!alloc)
+		return ERR_PTR(-ENOENT);
+
+	return mpam_class_alloc(level_idx, type);
+}
+
+/*
+ * Create a a device with this @hwpage_address, of class type:level_idx.
+ * class/component structures may be allocated.
+ * Returns the new device, or an ERR_PTR().
+ */
+struct mpam_device * __init
+__mpam_device_create(u8 level_idx, enum mpam_class_types type,
+			int component_id, const struct cpumask *fw_affinity,
+			phys_addr_t hwpage_address)
+{
+	struct mpam_device *dev;
+	struct mpam_class *class;
+	struct mpam_component *comp;
+
+	if (!fw_affinity)
+		fw_affinity = cpu_possible_mask;
+
+	mutex_lock(&mpam_devices_lock);
+	do {
+		class = mpam_class_get(level_idx, type, true);
+		if (IS_ERR(class)) {
+			dev = (void *)class;
+			break;
+		}
+
+		comp = mpam_component_get(class, component_id, true);
+		if (IS_ERR(comp)) {
+			dev = (void *)comp;
+			break;
+		}
+
+		/*
+		 * For caches we learn the affinity from the cache-id as CPUs
+		 * come online. For everything else, we have to be told.
+		 */
+		if (type != MPAM_CLASS_CACHE)
+			cpumask_or(&comp->fw_affinity, &comp->fw_affinity,
+					fw_affinity);
+
+		dev = mpam_device_alloc(comp);
+		if (IS_ERR(dev))
+			break;
+
+		dev->fw_affinity = *fw_affinity;
+		dev->hwpage_address = hwpage_address;
+		dev->mapped_hwpage = ioremap(hwpage_address, SZ_MPAM_DEVICE);
+		if (!dev->mapped_hwpage)
+			dev = ERR_PTR(-ENOMEM);
+	} while (0);
+	mutex_unlock(&mpam_devices_lock);
+
+	return dev;
+}
+
+static int mpam_cpus_have_feature(void)
+{
+	if (!cpus_have_const_cap(ARM64_HAS_MPAM))
+		return 0;
+	return 1;
+}
+
+/*
+ * prepare for initializing devices.
+ */
+int __init mpam_discovery_start(void)
+{
+	if (!mpam_cpus_have_feature())
+		return -EOPNOTSUPP;
+
+	return 0;
+}
+
+int __init mpam_discovery_complete(void)
+{
+	return 0;
+}
+
+void __init mpam_discovery_failed(void)
+{
+	struct mpam_class *class, *tmp;
+
+	mutex_lock(&mpam_devices_lock);
+	list_for_each_entry_safe(class, tmp, &mpam_classes, classes_list) {
+		mpam_class_destroy(class);
+		list_del(&class->classes_list);
+		kfree(class);
+	}
+	mutex_unlock(&mpam_devices_lock);
+}

arch/arm64/kernel/mpam/mpam_device.h

+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_ARM64_MPAM_DEVICE_H
+#define _ASM_ARM64_MPAM_DEVICE_H
+
+#include <linux/err.h>
+#include <linux/cpumask.h>
+#include <linux/types.h>
+
+/*
+ * Size of the memory mapped registers: 4K of feature page
+ * then 2x 4K bitmap registers
+ */
+#define SZ_MPAM_DEVICE  (3 * SZ_4K)
+
+enum mpam_class_types {
+	MPAM_CLASS_SMMU,
+	MPAM_CLASS_CACHE,   /* Well known caches, e.g. L2 */
+	MPAM_CLASS_MEMORY,  /* Main memory */
+	MPAM_CLASS_UNKNOWN, /* Everything else, e.g. TLBs etc */
+};
+
+/*
+ * An mpam_device corresponds to an MSC, an interface to a component's cache
+ * or bandwidth controls. It is associated with a set of CPUs, and a component.
+ * For resctrl the component is expected to be a well-known cache (e.g. L2).
+ * We may have multiple interfaces per component, each for a set of CPUs that
+ * share the same component.
+ */
+struct mpam_device {
+	/* member of mpam_component:devices */
+	struct list_head        comp_list;
+	struct mpam_component   *comp;
+
+	/* member of mpam_all_devices */
+	struct list_head        glbl_list;
+
+	/* The affinity learn't from firmware */
+	struct cpumask          fw_affinity;
+	/* of which these cpus are online */
+	struct cpumask          online_affinity;
+
+	spinlock_t              lock;
+	bool                    probed;
+
+	phys_addr_t             hwpage_address;
+	void __iomem            *mapped_hwpage;
+};
+
+/*
+ * A set of devices that share the same component. e.g. the MSCs that
+ * make up the L2 cache. This may be 1:1. Exposed to user-space as a domain by
+ * resctrl when the component is a well-known cache.
+ */
+struct mpam_component {
+	u32         comp_id;
+
+	/* mpam_devices in this domain */
+	struct list_head        devices;
+
+	struct cpumask          fw_affinity;
+
+	/* member of mpam_class:components */
+	struct list_head        class_list;
+};
+
+/*
+ * All the components of the same type at a particular level,
+ * e.g. all the L2 cache components. Exposed to user-space as a resource
+ * by resctrl when the component is a well-known cache. We may have additional
+ * classes such as system-caches, or internal components that are not exposed.
+ */
+struct mpam_class {
+	/*
+	 * resctrl expects to see an empty domain list if all 'those' CPUs are
+	 * offline. As we can't discover the cpu affinity of 'unknown' MSCs, we
+	 * need a second list.
+	 * mpam_components in this class.
+	 */
+	struct list_head        components;
+
+	struct cpumask          fw_affinity;
+
+	u8                      level;
+	enum mpam_class_types   type;
+
+	struct mutex            lock;
+
+	/* member of mpam_classes */
+	struct list_head        classes_list;
+};
+
+#endif /* _ASM_ARM64_MPAM_DEVICE_H */