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f65c9bb3 LJ |
1 | /****************************************************************************** |
2 | * pcpu.c | |
3 | * Management physical cpu in dom0, get pcpu info and provide sys interface | |
4 | * | |
5 | * Copyright (c) 2012 Intel Corporation | |
6 | * 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/or | |
10 | * modify it under the terms of the GNU General Public License version 2 | |
11 | * as published by the Free Software Foundation; or, when distributed | |
12 | * separately from the Linux kernel or incorporated into other | |
13 | * software packages, subject to the following license: | |
14 | * | |
15 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
16 | * of this source file (the "Software"), to deal in the Software without | |
17 | * 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 to | |
20 | * the following conditions: | |
21 | * | |
22 | * The above copyright notice and this permission notice shall be included in | |
23 | * all copies or substantial portions of the Software. | |
24 | * | |
25 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
26 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
27 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
28 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
29 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
30 | * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS | |
31 | * IN THE SOFTWARE. | |
32 | */ | |
33 | ||
283c0972 JP |
34 | #define pr_fmt(fmt) "xen_cpu: " fmt |
35 | ||
f65c9bb3 LJ |
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/xenbus.h> | |
44 | #include <xen/events.h> | |
45 | #include <xen/interface/platform.h> | |
46 | #include <asm/xen/hypervisor.h> | |
47 | #include <asm/xen/hypercall.h> | |
48 | ||
f65c9bb3 LJ |
49 | |
50 | /* | |
51 | * @cpu_id: Xen physical cpu logic number | |
52 | * @flags: Xen physical cpu status flag | |
53 | * - XEN_PCPU_FLAGS_ONLINE: cpu is online | |
54 | * - XEN_PCPU_FLAGS_INVALID: cpu is not present | |
55 | */ | |
56 | struct pcpu { | |
57 | struct list_head list; | |
58 | struct device dev; | |
59 | uint32_t cpu_id; | |
60 | uint32_t flags; | |
61 | }; | |
62 | ||
63 | static struct bus_type xen_pcpu_subsys = { | |
64 | .name = "xen_cpu", | |
65 | .dev_name = "xen_cpu", | |
66 | }; | |
67 | ||
68 | static DEFINE_MUTEX(xen_pcpu_lock); | |
69 | ||
70 | static LIST_HEAD(xen_pcpus); | |
71 | ||
72 | static int xen_pcpu_down(uint32_t cpu_id) | |
73 | { | |
74 | struct xen_platform_op op = { | |
75 | .cmd = XENPF_cpu_offline, | |
76 | .interface_version = XENPF_INTERFACE_VERSION, | |
77 | .u.cpu_ol.cpuid = cpu_id, | |
78 | }; | |
79 | ||
80 | return HYPERVISOR_dom0_op(&op); | |
81 | } | |
82 | ||
83 | static int xen_pcpu_up(uint32_t cpu_id) | |
84 | { | |
85 | struct xen_platform_op op = { | |
86 | .cmd = XENPF_cpu_online, | |
87 | .interface_version = XENPF_INTERFACE_VERSION, | |
88 | .u.cpu_ol.cpuid = cpu_id, | |
89 | }; | |
90 | ||
91 | return HYPERVISOR_dom0_op(&op); | |
92 | } | |
93 | ||
94 | static ssize_t show_online(struct device *dev, | |
95 | struct device_attribute *attr, | |
96 | char *buf) | |
97 | { | |
98 | struct pcpu *cpu = container_of(dev, struct pcpu, dev); | |
99 | ||
100 | return sprintf(buf, "%u\n", !!(cpu->flags & XEN_PCPU_FLAGS_ONLINE)); | |
101 | } | |
102 | ||
103 | static ssize_t __ref store_online(struct device *dev, | |
104 | struct device_attribute *attr, | |
105 | const char *buf, size_t count) | |
106 | { | |
107 | struct pcpu *pcpu = container_of(dev, struct pcpu, dev); | |
108 | unsigned long long val; | |
109 | ssize_t ret; | |
110 | ||
111 | if (!capable(CAP_SYS_ADMIN)) | |
112 | return -EPERM; | |
113 | ||
114 | if (kstrtoull(buf, 0, &val) < 0) | |
115 | return -EINVAL; | |
116 | ||
117 | switch (val) { | |
118 | case 0: | |
119 | ret = xen_pcpu_down(pcpu->cpu_id); | |
120 | break; | |
121 | case 1: | |
122 | ret = xen_pcpu_up(pcpu->cpu_id); | |
123 | break; | |
124 | default: | |
125 | ret = -EINVAL; | |
126 | } | |
127 | ||
128 | if (ret >= 0) | |
129 | ret = count; | |
130 | return ret; | |
131 | } | |
132 | static DEVICE_ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online); | |
133 | ||
134 | static bool xen_pcpu_online(uint32_t flags) | |
135 | { | |
136 | return !!(flags & XEN_PCPU_FLAGS_ONLINE); | |
137 | } | |
138 | ||
139 | static void pcpu_online_status(struct xenpf_pcpuinfo *info, | |
140 | struct pcpu *pcpu) | |
141 | { | |
142 | if (xen_pcpu_online(info->flags) && | |
143 | !xen_pcpu_online(pcpu->flags)) { | |
144 | /* the pcpu is onlined */ | |
145 | pcpu->flags |= XEN_PCPU_FLAGS_ONLINE; | |
146 | kobject_uevent(&pcpu->dev.kobj, KOBJ_ONLINE); | |
147 | } else if (!xen_pcpu_online(info->flags) && | |
148 | xen_pcpu_online(pcpu->flags)) { | |
149 | /* The pcpu is offlined */ | |
150 | pcpu->flags &= ~XEN_PCPU_FLAGS_ONLINE; | |
151 | kobject_uevent(&pcpu->dev.kobj, KOBJ_OFFLINE); | |
152 | } | |
153 | } | |
154 | ||
155 | static struct pcpu *get_pcpu(uint32_t cpu_id) | |
156 | { | |
157 | struct pcpu *pcpu; | |
158 | ||
159 | list_for_each_entry(pcpu, &xen_pcpus, list) { | |
160 | if (pcpu->cpu_id == cpu_id) | |
161 | return pcpu; | |
162 | } | |
163 | ||
164 | return NULL; | |
165 | } | |
166 | ||
167 | static void pcpu_release(struct device *dev) | |
168 | { | |
169 | struct pcpu *pcpu = container_of(dev, struct pcpu, dev); | |
170 | ||
171 | list_del(&pcpu->list); | |
172 | kfree(pcpu); | |
173 | } | |
174 | ||
175 | static void unregister_and_remove_pcpu(struct pcpu *pcpu) | |
176 | { | |
177 | struct device *dev; | |
178 | ||
179 | if (!pcpu) | |
180 | return; | |
181 | ||
182 | dev = &pcpu->dev; | |
183 | if (dev->id) | |
184 | device_remove_file(dev, &dev_attr_online); | |
185 | ||
186 | /* pcpu remove would be implicitly done */ | |
187 | device_unregister(dev); | |
188 | } | |
189 | ||
190 | static int register_pcpu(struct pcpu *pcpu) | |
191 | { | |
192 | struct device *dev; | |
193 | int err = -EINVAL; | |
194 | ||
195 | if (!pcpu) | |
196 | return err; | |
197 | ||
198 | dev = &pcpu->dev; | |
199 | dev->bus = &xen_pcpu_subsys; | |
200 | dev->id = pcpu->cpu_id; | |
201 | dev->release = pcpu_release; | |
202 | ||
203 | err = device_register(dev); | |
204 | if (err) { | |
205 | pcpu_release(dev); | |
206 | return err; | |
207 | } | |
208 | ||
209 | /* | |
210 | * Xen never offline cpu0 due to several restrictions | |
211 | * and assumptions. This basically doesn't add a sys control | |
212 | * to user, one cannot attempt to offline BSP. | |
213 | */ | |
214 | if (dev->id) { | |
215 | err = device_create_file(dev, &dev_attr_online); | |
216 | if (err) { | |
217 | device_unregister(dev); | |
218 | return err; | |
219 | } | |
220 | } | |
221 | ||
222 | return 0; | |
223 | } | |
224 | ||
225 | static struct pcpu *create_and_register_pcpu(struct xenpf_pcpuinfo *info) | |
226 | { | |
227 | struct pcpu *pcpu; | |
228 | int err; | |
229 | ||
230 | if (info->flags & XEN_PCPU_FLAGS_INVALID) | |
231 | return ERR_PTR(-ENODEV); | |
232 | ||
233 | pcpu = kzalloc(sizeof(struct pcpu), GFP_KERNEL); | |
234 | if (!pcpu) | |
235 | return ERR_PTR(-ENOMEM); | |
236 | ||
237 | INIT_LIST_HEAD(&pcpu->list); | |
238 | pcpu->cpu_id = info->xen_cpuid; | |
239 | pcpu->flags = info->flags; | |
240 | ||
241 | /* Need hold on xen_pcpu_lock before pcpu list manipulations */ | |
242 | list_add_tail(&pcpu->list, &xen_pcpus); | |
243 | ||
244 | err = register_pcpu(pcpu); | |
245 | if (err) { | |
283c0972 | 246 | pr_warn("Failed to register pcpu%u\n", info->xen_cpuid); |
f65c9bb3 LJ |
247 | return ERR_PTR(-ENOENT); |
248 | } | |
249 | ||
250 | return pcpu; | |
251 | } | |
252 | ||
253 | /* | |
254 | * Caller should hold the xen_pcpu_lock | |
255 | */ | |
256 | static int sync_pcpu(uint32_t cpu, uint32_t *max_cpu) | |
257 | { | |
258 | int ret; | |
259 | struct pcpu *pcpu = NULL; | |
260 | struct xenpf_pcpuinfo *info; | |
261 | struct xen_platform_op op = { | |
262 | .cmd = XENPF_get_cpuinfo, | |
263 | .interface_version = XENPF_INTERFACE_VERSION, | |
264 | .u.pcpu_info.xen_cpuid = cpu, | |
265 | }; | |
266 | ||
267 | ret = HYPERVISOR_dom0_op(&op); | |
268 | if (ret) | |
269 | return ret; | |
270 | ||
271 | info = &op.u.pcpu_info; | |
272 | if (max_cpu) | |
273 | *max_cpu = info->max_present; | |
274 | ||
275 | pcpu = get_pcpu(cpu); | |
276 | ||
277 | /* | |
278 | * Only those at cpu present map has its sys interface. | |
279 | */ | |
280 | if (info->flags & XEN_PCPU_FLAGS_INVALID) { | |
4f8c8527 | 281 | unregister_and_remove_pcpu(pcpu); |
f65c9bb3 LJ |
282 | return 0; |
283 | } | |
284 | ||
285 | if (!pcpu) { | |
286 | pcpu = create_and_register_pcpu(info); | |
287 | if (IS_ERR_OR_NULL(pcpu)) | |
288 | return -ENODEV; | |
289 | } else | |
290 | pcpu_online_status(info, pcpu); | |
291 | ||
292 | return 0; | |
293 | } | |
294 | ||
295 | /* | |
296 | * Sync dom0's pcpu information with xen hypervisor's | |
297 | */ | |
298 | static int xen_sync_pcpus(void) | |
299 | { | |
300 | /* | |
301 | * Boot cpu always have cpu_id 0 in xen | |
302 | */ | |
303 | uint32_t cpu = 0, max_cpu = 0; | |
304 | int err = 0; | |
305 | struct pcpu *pcpu, *tmp; | |
306 | ||
307 | mutex_lock(&xen_pcpu_lock); | |
308 | ||
309 | while (!err && (cpu <= max_cpu)) { | |
310 | err = sync_pcpu(cpu, &max_cpu); | |
311 | cpu++; | |
312 | } | |
313 | ||
314 | if (err) | |
315 | list_for_each_entry_safe(pcpu, tmp, &xen_pcpus, list) | |
316 | unregister_and_remove_pcpu(pcpu); | |
317 | ||
318 | mutex_unlock(&xen_pcpu_lock); | |
319 | ||
320 | return err; | |
321 | } | |
322 | ||
323 | static void xen_pcpu_work_fn(struct work_struct *work) | |
324 | { | |
325 | xen_sync_pcpus(); | |
326 | } | |
327 | static DECLARE_WORK(xen_pcpu_work, xen_pcpu_work_fn); | |
328 | ||
329 | static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id) | |
330 | { | |
331 | schedule_work(&xen_pcpu_work); | |
332 | return IRQ_HANDLED; | |
333 | } | |
334 | ||
39adc483 LJ |
335 | /* Sync with Xen hypervisor after cpu hotadded */ |
336 | void xen_pcpu_hotplug_sync(void) | |
337 | { | |
338 | schedule_work(&xen_pcpu_work); | |
339 | } | |
340 | EXPORT_SYMBOL_GPL(xen_pcpu_hotplug_sync); | |
341 | ||
342 | /* | |
343 | * For hypervisor presented cpu, return logic cpu id; | |
344 | * For hypervisor non-presented cpu, return -ENODEV. | |
345 | */ | |
346 | int xen_pcpu_id(uint32_t acpi_id) | |
347 | { | |
348 | int cpu_id = 0, max_id = 0; | |
349 | struct xen_platform_op op; | |
350 | ||
351 | op.cmd = XENPF_get_cpuinfo; | |
352 | while (cpu_id <= max_id) { | |
353 | op.u.pcpu_info.xen_cpuid = cpu_id; | |
354 | if (HYPERVISOR_dom0_op(&op)) { | |
355 | cpu_id++; | |
356 | continue; | |
357 | } | |
358 | ||
359 | if (acpi_id == op.u.pcpu_info.acpi_id) | |
360 | return cpu_id; | |
361 | if (op.u.pcpu_info.max_present > max_id) | |
362 | max_id = op.u.pcpu_info.max_present; | |
363 | cpu_id++; | |
364 | } | |
365 | ||
366 | return -ENODEV; | |
367 | } | |
368 | EXPORT_SYMBOL_GPL(xen_pcpu_id); | |
369 | ||
f65c9bb3 LJ |
370 | static int __init xen_pcpu_init(void) |
371 | { | |
372 | int irq, ret; | |
373 | ||
374 | if (!xen_initial_domain()) | |
375 | return -ENODEV; | |
376 | ||
377 | irq = bind_virq_to_irqhandler(VIRQ_PCPU_STATE, 0, | |
378 | xen_pcpu_interrupt, 0, | |
379 | "xen-pcpu", NULL); | |
380 | if (irq < 0) { | |
283c0972 | 381 | pr_warn("Failed to bind pcpu virq\n"); |
f65c9bb3 LJ |
382 | return irq; |
383 | } | |
384 | ||
385 | ret = subsys_system_register(&xen_pcpu_subsys, NULL); | |
386 | if (ret) { | |
283c0972 | 387 | pr_warn("Failed to register pcpu subsys\n"); |
f65c9bb3 LJ |
388 | goto err1; |
389 | } | |
390 | ||
391 | ret = xen_sync_pcpus(); | |
392 | if (ret) { | |
283c0972 | 393 | pr_warn("Failed to sync pcpu info\n"); |
f65c9bb3 LJ |
394 | goto err2; |
395 | } | |
396 | ||
397 | return 0; | |
398 | ||
399 | err2: | |
400 | bus_unregister(&xen_pcpu_subsys); | |
401 | err1: | |
402 | unbind_from_irqhandler(irq, NULL); | |
403 | return ret; | |
404 | } | |
405 | arch_initcall(xen_pcpu_init); |