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1/******************************************************************************2 * pcpu.c3 * Management physical cpu in dom0, get pcpu info and provide sys interface4 *5 * Copyright (c) 2012 Intel Corporation6 * Author: Liu, Jinsong <jinsong.liu@intel.com>7 * Author: Jiang, Yunhong <yunhong.jiang@intel.com>8 *9 * This program is free software; you can redistribute it and/or10 * modify it under the terms of the GNU General Public License version 211 * as published by the Free Software Foundation; or, when distributed12 * separately from the Linux kernel or incorporated into other13 * software packages, subject to the following license:14 *15 * Permission is hereby granted, free of charge, to any person obtaining a copy16 * of this source file (the "Software"), to deal in the Software without17 * restriction, including without limitation the rights to use, copy, modify,18 * merge, publish, distribute, sublicense, and/or sell copies of the Software,19 * and to permit persons to whom the Software is furnished to do so, subject to20 * the following conditions:21 *22 * The above copyright notice and this permission notice shall be included in23 * all copies or substantial portions of the Software.24 *25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR26 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,27 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE28 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER29 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING30 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS31 * IN THE SOFTWARE.32 */33 34#define pr_fmt(fmt) "xen_cpu: " fmt35 36#include <linux/interrupt.h>37#include <linux/spinlock.h>38#include <linux/cpu.h>39#include <linux/stat.h>40#include <linux/capability.h>41 42#include <xen/xen.h>43#include <xen/acpi.h>44#include <xen/xenbus.h>45#include <xen/events.h>46#include <xen/interface/platform.h>47#include <asm/xen/hypervisor.h>48#include <asm/xen/hypercall.h>49 50#ifdef CONFIG_ACPI51#include <acpi/processor.h>52#endif53 54/*55 * @cpu_id: Xen physical cpu logic number56 * @flags: Xen physical cpu status flag57 * - XEN_PCPU_FLAGS_ONLINE: cpu is online58 * - XEN_PCPU_FLAGS_INVALID: cpu is not present59 */60struct pcpu {61 struct list_head list;62 struct device dev;63 uint32_t cpu_id;64 uint32_t acpi_id;65 uint32_t flags;66};67 68static const struct bus_type xen_pcpu_subsys = {69 .name = "xen_cpu",70 .dev_name = "xen_cpu",71};72 73static DEFINE_MUTEX(xen_pcpu_lock);74 75static LIST_HEAD(xen_pcpus);76 77static int xen_pcpu_down(uint32_t cpu_id)78{79 struct xen_platform_op op = {80 .cmd = XENPF_cpu_offline,81 .interface_version = XENPF_INTERFACE_VERSION,82 .u.cpu_ol.cpuid = cpu_id,83 };84 85 return HYPERVISOR_platform_op(&op);86}87 88static int xen_pcpu_up(uint32_t cpu_id)89{90 struct xen_platform_op op = {91 .cmd = XENPF_cpu_online,92 .interface_version = XENPF_INTERFACE_VERSION,93 .u.cpu_ol.cpuid = cpu_id,94 };95 96 return HYPERVISOR_platform_op(&op);97}98 99static ssize_t online_show(struct device *dev,100 struct device_attribute *attr,101 char *buf)102{103 struct pcpu *cpu = container_of(dev, struct pcpu, dev);104 105 return sprintf(buf, "%u\n", !!(cpu->flags & XEN_PCPU_FLAGS_ONLINE));106}107 108static ssize_t __ref online_store(struct device *dev,109 struct device_attribute *attr,110 const char *buf, size_t count)111{112 struct pcpu *pcpu = container_of(dev, struct pcpu, dev);113 unsigned long long val;114 ssize_t ret;115 116 if (!capable(CAP_SYS_ADMIN))117 return -EPERM;118 119 if (kstrtoull(buf, 0, &val) < 0)120 return -EINVAL;121 122 switch (val) {123 case 0:124 ret = xen_pcpu_down(pcpu->cpu_id);125 break;126 case 1:127 ret = xen_pcpu_up(pcpu->cpu_id);128 break;129 default:130 ret = -EINVAL;131 }132 133 if (ret >= 0)134 ret = count;135 return ret;136}137static DEVICE_ATTR_RW(online);138 139static struct attribute *pcpu_dev_attrs[] = {140 &dev_attr_online.attr,141 NULL142};143 144static umode_t pcpu_dev_is_visible(struct kobject *kobj,145 struct attribute *attr, int idx)146{147 struct device *dev = kobj_to_dev(kobj);148 /*149 * Xen never offline cpu0 due to several restrictions150 * and assumptions. This basically doesn't add a sys control151 * to user, one cannot attempt to offline BSP.152 */153 return dev->id ? attr->mode : 0;154}155 156static const struct attribute_group pcpu_dev_group = {157 .attrs = pcpu_dev_attrs,158 .is_visible = pcpu_dev_is_visible,159};160 161static const struct attribute_group *pcpu_dev_groups[] = {162 &pcpu_dev_group,163 NULL164};165 166static bool xen_pcpu_online(uint32_t flags)167{168 return !!(flags & XEN_PCPU_FLAGS_ONLINE);169}170 171static void pcpu_online_status(struct xenpf_pcpuinfo *info,172 struct pcpu *pcpu)173{174 if (xen_pcpu_online(info->flags) &&175 !xen_pcpu_online(pcpu->flags)) {176 /* the pcpu is onlined */177 pcpu->flags |= XEN_PCPU_FLAGS_ONLINE;178 kobject_uevent(&pcpu->dev.kobj, KOBJ_ONLINE);179 } else if (!xen_pcpu_online(info->flags) &&180 xen_pcpu_online(pcpu->flags)) {181 /* The pcpu is offlined */182 pcpu->flags &= ~XEN_PCPU_FLAGS_ONLINE;183 kobject_uevent(&pcpu->dev.kobj, KOBJ_OFFLINE);184 }185}186 187static struct pcpu *get_pcpu(uint32_t cpu_id)188{189 struct pcpu *pcpu;190 191 list_for_each_entry(pcpu, &xen_pcpus, list) {192 if (pcpu->cpu_id == cpu_id)193 return pcpu;194 }195 196 return NULL;197}198 199static void pcpu_release(struct device *dev)200{201 struct pcpu *pcpu = container_of(dev, struct pcpu, dev);202 203 list_del(&pcpu->list);204 kfree(pcpu);205}206 207static void unregister_and_remove_pcpu(struct pcpu *pcpu)208{209 struct device *dev;210 211 if (!pcpu)212 return;213 214 dev = &pcpu->dev;215 /* pcpu remove would be implicitly done */216 device_unregister(dev);217}218 219static int register_pcpu(struct pcpu *pcpu)220{221 struct device *dev;222 int err = -EINVAL;223 224 if (!pcpu)225 return err;226 227 dev = &pcpu->dev;228 dev->bus = &xen_pcpu_subsys;229 dev->id = pcpu->cpu_id;230 dev->release = pcpu_release;231 dev->groups = pcpu_dev_groups;232 233 err = device_register(dev);234 if (err) {235 put_device(dev);236 return err;237 }238 239 return 0;240}241 242static struct pcpu *create_and_register_pcpu(struct xenpf_pcpuinfo *info)243{244 struct pcpu *pcpu;245 int err;246 247 if (info->flags & XEN_PCPU_FLAGS_INVALID)248 return ERR_PTR(-ENODEV);249 250 pcpu = kzalloc(sizeof(struct pcpu), GFP_KERNEL);251 if (!pcpu)252 return ERR_PTR(-ENOMEM);253 254 INIT_LIST_HEAD(&pcpu->list);255 pcpu->cpu_id = info->xen_cpuid;256 pcpu->acpi_id = info->acpi_id;257 pcpu->flags = info->flags;258 259 /* Need hold on xen_pcpu_lock before pcpu list manipulations */260 list_add_tail(&pcpu->list, &xen_pcpus);261 262 err = register_pcpu(pcpu);263 if (err) {264 pr_warn("Failed to register pcpu%u\n", info->xen_cpuid);265 return ERR_PTR(-ENOENT);266 }267 268 return pcpu;269}270 271/*272 * Caller should hold the xen_pcpu_lock273 */274static int sync_pcpu(uint32_t cpu, uint32_t *max_cpu)275{276 int ret;277 struct pcpu *pcpu = NULL;278 struct xenpf_pcpuinfo *info;279 struct xen_platform_op op = {280 .cmd = XENPF_get_cpuinfo,281 .interface_version = XENPF_INTERFACE_VERSION,282 .u.pcpu_info.xen_cpuid = cpu,283 };284 285 ret = HYPERVISOR_platform_op(&op);286 if (ret)287 return ret;288 289 info = &op.u.pcpu_info;290 if (max_cpu)291 *max_cpu = info->max_present;292 293 pcpu = get_pcpu(cpu);294 295 /*296 * Only those at cpu present map has its sys interface.297 */298 if (info->flags & XEN_PCPU_FLAGS_INVALID) {299 unregister_and_remove_pcpu(pcpu);300 return 0;301 }302 303 if (!pcpu) {304 pcpu = create_and_register_pcpu(info);305 if (IS_ERR_OR_NULL(pcpu))306 return -ENODEV;307 } else308 pcpu_online_status(info, pcpu);309 310 return 0;311}312 313/*314 * Sync dom0's pcpu information with xen hypervisor's315 */316static int xen_sync_pcpus(void)317{318 /*319 * Boot cpu always have cpu_id 0 in xen320 */321 uint32_t cpu = 0, max_cpu = 0;322 int err = 0;323 struct pcpu *pcpu, *tmp;324 325 mutex_lock(&xen_pcpu_lock);326 327 while (!err && (cpu <= max_cpu)) {328 err = sync_pcpu(cpu, &max_cpu);329 cpu++;330 }331 332 if (err)333 list_for_each_entry_safe(pcpu, tmp, &xen_pcpus, list)334 unregister_and_remove_pcpu(pcpu);335 336 mutex_unlock(&xen_pcpu_lock);337 338 return err;339}340 341static void xen_pcpu_work_fn(struct work_struct *work)342{343 xen_sync_pcpus();344}345static DECLARE_WORK(xen_pcpu_work, xen_pcpu_work_fn);346 347static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id)348{349 schedule_work(&xen_pcpu_work);350 return IRQ_HANDLED;351}352 353static int __init xen_pcpu_init(void)354{355 int irq, ret;356 357 if (!xen_initial_domain())358 return -ENODEV;359 360 irq = bind_virq_to_irqhandler(VIRQ_PCPU_STATE, 0,361 xen_pcpu_interrupt, 0,362 "xen-pcpu", NULL);363 if (irq < 0) {364 pr_warn("Failed to bind pcpu virq\n");365 return irq;366 }367 368 ret = subsys_system_register(&xen_pcpu_subsys, NULL);369 if (ret) {370 pr_warn("Failed to register pcpu subsys\n");371 goto err1;372 }373 374 ret = xen_sync_pcpus();375 if (ret) {376 pr_warn("Failed to sync pcpu info\n");377 goto err2;378 }379 380 return 0;381 382err2:383 bus_unregister(&xen_pcpu_subsys);384err1:385 unbind_from_irqhandler(irq, NULL);386 return ret;387}388arch_initcall(xen_pcpu_init);389 390#ifdef CONFIG_ACPI391bool __init xen_processor_present(uint32_t acpi_id)392{393 const struct pcpu *pcpu;394 bool online = false;395 396 mutex_lock(&xen_pcpu_lock);397 list_for_each_entry(pcpu, &xen_pcpus, list)398 if (pcpu->acpi_id == acpi_id) {399 online = pcpu->flags & XEN_PCPU_FLAGS_ONLINE;400 break;401 }402 mutex_unlock(&xen_pcpu_lock);403 404 return online;405}406 407void xen_sanitize_proc_cap_bits(uint32_t *cap)408{409 struct xen_platform_op op = {410 .cmd = XENPF_set_processor_pminfo,411 .u.set_pminfo.id = -1,412 .u.set_pminfo.type = XEN_PM_PDC,413 };414 u32 buf[3] = { ACPI_PDC_REVISION_ID, 1, *cap };415 int ret;416 417 set_xen_guest_handle(op.u.set_pminfo.pdc, buf);418 ret = HYPERVISOR_platform_op(&op);419 if (ret)420 pr_err("sanitize of _PDC buffer bits from Xen failed: %d\n",421 ret);422 else423 *cap = buf[2];424}425#endif426