/****************************************************************************** * pcpu.c * Management physical cpu in dom0, get pcpu info and provide sys interface * * Copyright (c) 2012 Intel Corporation * Author: Liu, Jinsong <jinsong.liu@intel.com> * Author: Jiang, Yunhong <yunhong.jiang@intel.com> * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #define pr_fmt(fmt) "xen_cpu: " fmt #include <linux/interrupt.h>#include <linux/spinlock.h>#include <linux/cpu.h>#include <linux/stat.h>#include <linux/capability.h> #include <xen/xen.h>#include <xen/acpi.h>#include <xen/xenbus.h>#include <xen/events.h>#include <xen/interface/platform.h>#include <asm/xen/hypervisor.h>#include <asm/xen/hypercall.h> #ifdef CONFIG_ACPI#include <acpi/processor.h>#endif /* * @cpu_id: Xen physical cpu logic number * @flags: Xen physical cpu status flag * - XEN_PCPU_FLAGS_ONLINE: cpu is online * - XEN_PCPU_FLAGS_INVALID: cpu is not present */struct pcpu {	struct list_head list;	struct device dev;	uint32_t cpu_id;	uint32_t acpi_id;	uint32_t flags;}; static const struct bus_type xen_pcpu_subsys = {	.name = "xen_cpu",	.dev_name = "xen_cpu",}; static DEFINE_MUTEX(xen_pcpu_lock); static LIST_HEAD(xen_pcpus); static int xen_pcpu_down(uint32_t cpu_id){	struct xen_platform_op op = {		.cmd			= XENPF_cpu_offline,		.interface_version	= XENPF_INTERFACE_VERSION,		.u.cpu_ol.cpuid		= cpu_id,	}; 	return HYPERVISOR_platform_op(&op);} static int xen_pcpu_up(uint32_t cpu_id){	struct xen_platform_op op = {		.cmd			= XENPF_cpu_online,		.interface_version	= XENPF_INTERFACE_VERSION,		.u.cpu_ol.cpuid		= cpu_id,	}; 	return HYPERVISOR_platform_op(&op);} static ssize_t online_show(struct device *dev,			   struct device_attribute *attr,			   char *buf){	struct pcpu *cpu = container_of(dev, struct pcpu, dev); 	return sprintf(buf, "%u\n", !!(cpu->flags & XEN_PCPU_FLAGS_ONLINE));} static ssize_t online_store(struct device *dev,				  struct device_attribute *attr,				  const char *buf, size_t count){	struct pcpu *pcpu = container_of(dev, struct pcpu, dev);	unsigned long long val;	ssize_t ret; 	if (!capable(CAP_SYS_ADMIN))		return -EPERM; 	if (kstrtoull(buf, 0, &val) < 0)		return -EINVAL; 	switch (val) {	case 0:		ret = xen_pcpu_down(pcpu->cpu_id);		break;	case 1:		ret = xen_pcpu_up(pcpu->cpu_id);		break;	default:		ret = -EINVAL;	} 	if (ret >= 0)		ret = count;	return ret;}static DEVICE_ATTR_RW(online); static struct attribute *pcpu_dev_attrs[] = {	&dev_attr_online.attr,	NULL}; static umode_t pcpu_dev_is_visible(struct kobject *kobj,				   struct attribute *attr, int idx){	struct device *dev = kobj_to_dev(kobj);	/*	 * Xen never offline cpu0 due to several restrictions	 * and assumptions. This basically doesn't add a sys control	 * to user, one cannot attempt to offline BSP.	 */	return dev->id ? attr->mode : 0;} static const struct attribute_group pcpu_dev_group = {	.attrs = pcpu_dev_attrs,	.is_visible = pcpu_dev_is_visible,}; static const struct attribute_group *pcpu_dev_groups[] = {	&pcpu_dev_group,	NULL}; static bool xen_pcpu_online(uint32_t flags){	return !!(flags & XEN_PCPU_FLAGS_ONLINE);} static void pcpu_online_status(struct xenpf_pcpuinfo *info,			       struct pcpu *pcpu){	if (xen_pcpu_online(info->flags) &&	   !xen_pcpu_online(pcpu->flags)) {		/* the pcpu is onlined */		pcpu->flags |= XEN_PCPU_FLAGS_ONLINE;		kobject_uevent(&pcpu->dev.kobj, KOBJ_ONLINE);	} else if (!xen_pcpu_online(info->flags) &&		    xen_pcpu_online(pcpu->flags)) {		/* The pcpu is offlined */		pcpu->flags &= ~XEN_PCPU_FLAGS_ONLINE;		kobject_uevent(&pcpu->dev.kobj, KOBJ_OFFLINE);	}} static struct pcpu *get_pcpu(uint32_t cpu_id){	struct pcpu *pcpu; 	list_for_each_entry(pcpu, &xen_pcpus, list) {		if (pcpu->cpu_id == cpu_id)			return pcpu;	} 	return NULL;} static void pcpu_release(struct device *dev){	struct pcpu *pcpu = container_of(dev, struct pcpu, dev); 	list_del(&pcpu->list);	kfree(pcpu);} static void unregister_and_remove_pcpu(struct pcpu *pcpu){	struct device *dev; 	if (!pcpu)		return; 	dev = &pcpu->dev;	/* pcpu remove would be implicitly done */	device_unregister(dev);} static int register_pcpu(struct pcpu *pcpu){	struct device *dev;	int err = -EINVAL; 	if (!pcpu)		return err; 	dev = &pcpu->dev;	dev->bus = &xen_pcpu_subsys;	dev->id = pcpu->cpu_id;	dev->release = pcpu_release;	dev->groups = pcpu_dev_groups; 	err = device_register(dev);	if (err) {		put_device(dev);		return err;	} 	return 0;} static struct pcpu *create_and_register_pcpu(struct xenpf_pcpuinfo *info){	struct pcpu *pcpu;	int err; 	if (info->flags & XEN_PCPU_FLAGS_INVALID)		return ERR_PTR(-ENODEV); 	pcpu = kzalloc_obj(struct pcpu);	if (!pcpu)		return ERR_PTR(-ENOMEM); 	INIT_LIST_HEAD(&pcpu->list);	pcpu->cpu_id = info->xen_cpuid;	pcpu->acpi_id = info->acpi_id;	pcpu->flags = info->flags; 	/* Need hold on xen_pcpu_lock before pcpu list manipulations */	list_add_tail(&pcpu->list, &xen_pcpus); 	err = register_pcpu(pcpu);	if (err) {		pr_warn("Failed to register pcpu%u\n", info->xen_cpuid);		return ERR_PTR(-ENOENT);	} 	return pcpu;} /* * Caller should hold the xen_pcpu_lock */static int sync_pcpu(uint32_t cpu, uint32_t *max_cpu){	int ret;	struct pcpu *pcpu = NULL;	struct xenpf_pcpuinfo *info;	struct xen_platform_op op = {		.cmd                   = XENPF_get_cpuinfo,		.interface_version     = XENPF_INTERFACE_VERSION,		.u.pcpu_info.xen_cpuid = cpu,	}; 	ret = HYPERVISOR_platform_op(&op);	if (ret)		return ret; 	info = &op.u.pcpu_info;	if (max_cpu)		*max_cpu = info->max_present; 	pcpu = get_pcpu(cpu); 	/*	 * Only those at cpu present map has its sys interface.	 */	if (info->flags & XEN_PCPU_FLAGS_INVALID) {		unregister_and_remove_pcpu(pcpu);		return 0;	} 	if (!pcpu) {		pcpu = create_and_register_pcpu(info);		if (IS_ERR_OR_NULL(pcpu))			return -ENODEV;	} else		pcpu_online_status(info, pcpu); 	return 0;} /* * Sync dom0's pcpu information with xen hypervisor's */static int xen_sync_pcpus(void){	/*	 * Boot cpu always have cpu_id 0 in xen	 */	uint32_t cpu = 0, max_cpu = 0;	int err = 0;	struct pcpu *pcpu, *tmp; 	mutex_lock(&xen_pcpu_lock); 	while (!err && (cpu <= max_cpu)) {		err = sync_pcpu(cpu, &max_cpu);		cpu++;	} 	if (err)		list_for_each_entry_safe(pcpu, tmp, &xen_pcpus, list)			unregister_and_remove_pcpu(pcpu); 	mutex_unlock(&xen_pcpu_lock); 	return err;} static void xen_pcpu_work_fn(struct work_struct *work){	xen_sync_pcpus();}static DECLARE_WORK(xen_pcpu_work, xen_pcpu_work_fn); static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id){	schedule_work(&xen_pcpu_work);	return IRQ_HANDLED;} static int __init xen_pcpu_init(void){	int irq, ret; 	if (!xen_initial_domain())		return -ENODEV; 	irq = bind_virq_to_irqhandler(VIRQ_PCPU_STATE, 0,				      xen_pcpu_interrupt, 0,				      "xen-pcpu", NULL);	if (irq < 0) {		pr_warn("Failed to bind pcpu virq\n");		return irq;	} 	ret = subsys_system_register(&xen_pcpu_subsys, NULL);	if (ret) {		pr_warn("Failed to register pcpu subsys\n");		goto err1;	} 	ret = xen_sync_pcpus();	if (ret) {		pr_warn("Failed to sync pcpu info\n");		goto err2;	} 	return 0; err2:	bus_unregister(&xen_pcpu_subsys);err1:	unbind_from_irqhandler(irq, NULL);	return ret;}arch_initcall(xen_pcpu_init); #ifdef CONFIG_ACPIbool __init xen_processor_present(uint32_t acpi_id){	const struct pcpu *pcpu;	bool online = false; 	mutex_lock(&xen_pcpu_lock);	list_for_each_entry(pcpu, &xen_pcpus, list)		if (pcpu->acpi_id == acpi_id) {			online = pcpu->flags & XEN_PCPU_FLAGS_ONLINE;			break;		}	mutex_unlock(&xen_pcpu_lock); 	return online;} void xen_sanitize_proc_cap_bits(uint32_t *cap){	struct xen_platform_op op = {		.cmd			= XENPF_set_processor_pminfo,		.u.set_pminfo.id	= -1,		.u.set_pminfo.type	= XEN_PM_PDC,	};	u32 buf[3] = { ACPI_PDC_REVISION_ID, 1, *cap };	int ret; 	set_xen_guest_handle(op.u.set_pminfo.pdc, buf);	ret = HYPERVISOR_platform_op(&op);	if (ret)		pr_err("sanitize of _PDC buffer bits from Xen failed: %d\n",		       ret);	else		*cap = buf[2];}#endif