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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> | |
6cb606f1 | 43 | #include <xen/acpi.h> |
f65c9bb3 LJ |
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 | ||
f65c9bb3 LJ |
50 | |
51 | /* | |
52 | * @cpu_id: Xen physical cpu logic number | |
53 | * @flags: Xen physical cpu status flag | |
54 | * - XEN_PCPU_FLAGS_ONLINE: cpu is online | |
55 | * - XEN_PCPU_FLAGS_INVALID: cpu is not present | |
56 | */ | |
57 | struct pcpu { | |
58 | struct list_head list; | |
59 | struct device dev; | |
60 | uint32_t cpu_id; | |
073828e9 | 61 | uint32_t acpi_id; |
f65c9bb3 LJ |
62 | uint32_t flags; |
63 | }; | |
64 | ||
65 | static struct bus_type xen_pcpu_subsys = { | |
66 | .name = "xen_cpu", | |
67 | .dev_name = "xen_cpu", | |
68 | }; | |
69 | ||
70 | static DEFINE_MUTEX(xen_pcpu_lock); | |
71 | ||
72 | static LIST_HEAD(xen_pcpus); | |
73 | ||
74 | static int xen_pcpu_down(uint32_t cpu_id) | |
75 | { | |
76 | struct xen_platform_op op = { | |
77 | .cmd = XENPF_cpu_offline, | |
78 | .interface_version = XENPF_INTERFACE_VERSION, | |
79 | .u.cpu_ol.cpuid = cpu_id, | |
80 | }; | |
81 | ||
cfafae94 | 82 | return HYPERVISOR_platform_op(&op); |
f65c9bb3 LJ |
83 | } |
84 | ||
85 | static int xen_pcpu_up(uint32_t cpu_id) | |
86 | { | |
87 | struct xen_platform_op op = { | |
88 | .cmd = XENPF_cpu_online, | |
89 | .interface_version = XENPF_INTERFACE_VERSION, | |
90 | .u.cpu_ol.cpuid = cpu_id, | |
91 | }; | |
92 | ||
cfafae94 | 93 | return HYPERVISOR_platform_op(&op); |
f65c9bb3 LJ |
94 | } |
95 | ||
20600617 | 96 | static ssize_t online_show(struct device *dev, |
f65c9bb3 LJ |
97 | struct device_attribute *attr, |
98 | char *buf) | |
99 | { | |
100 | struct pcpu *cpu = container_of(dev, struct pcpu, dev); | |
101 | ||
102 | return sprintf(buf, "%u\n", !!(cpu->flags & XEN_PCPU_FLAGS_ONLINE)); | |
103 | } | |
104 | ||
20600617 | 105 | static ssize_t __ref online_store(struct device *dev, |
f65c9bb3 LJ |
106 | struct device_attribute *attr, |
107 | const char *buf, size_t count) | |
108 | { | |
109 | struct pcpu *pcpu = container_of(dev, struct pcpu, dev); | |
110 | unsigned long long val; | |
111 | ssize_t ret; | |
112 | ||
113 | if (!capable(CAP_SYS_ADMIN)) | |
114 | return -EPERM; | |
115 | ||
116 | if (kstrtoull(buf, 0, &val) < 0) | |
117 | return -EINVAL; | |
118 | ||
119 | switch (val) { | |
120 | case 0: | |
121 | ret = xen_pcpu_down(pcpu->cpu_id); | |
122 | break; | |
123 | case 1: | |
124 | ret = xen_pcpu_up(pcpu->cpu_id); | |
125 | break; | |
126 | default: | |
127 | ret = -EINVAL; | |
128 | } | |
129 | ||
130 | if (ret >= 0) | |
131 | ret = count; | |
132 | return ret; | |
133 | } | |
20600617 | 134 | static DEVICE_ATTR_RW(online); |
f65c9bb3 | 135 | |
4644e5ab TI |
136 | static struct attribute *pcpu_dev_attrs[] = { |
137 | &dev_attr_online.attr, | |
138 | NULL | |
139 | }; | |
140 | ||
141 | static umode_t pcpu_dev_is_visible(struct kobject *kobj, | |
142 | struct attribute *attr, int idx) | |
143 | { | |
144 | struct device *dev = kobj_to_dev(kobj); | |
145 | /* | |
146 | * Xen never offline cpu0 due to several restrictions | |
147 | * and assumptions. This basically doesn't add a sys control | |
148 | * to user, one cannot attempt to offline BSP. | |
149 | */ | |
150 | return dev->id ? attr->mode : 0; | |
151 | } | |
152 | ||
153 | static const struct attribute_group pcpu_dev_group = { | |
154 | .attrs = pcpu_dev_attrs, | |
155 | .is_visible = pcpu_dev_is_visible, | |
156 | }; | |
157 | ||
158 | static const struct attribute_group *pcpu_dev_groups[] = { | |
159 | &pcpu_dev_group, | |
160 | NULL | |
161 | }; | |
162 | ||
f65c9bb3 LJ |
163 | static bool xen_pcpu_online(uint32_t flags) |
164 | { | |
165 | return !!(flags & XEN_PCPU_FLAGS_ONLINE); | |
166 | } | |
167 | ||
168 | static void pcpu_online_status(struct xenpf_pcpuinfo *info, | |
169 | struct pcpu *pcpu) | |
170 | { | |
171 | if (xen_pcpu_online(info->flags) && | |
172 | !xen_pcpu_online(pcpu->flags)) { | |
173 | /* the pcpu is onlined */ | |
174 | pcpu->flags |= XEN_PCPU_FLAGS_ONLINE; | |
175 | kobject_uevent(&pcpu->dev.kobj, KOBJ_ONLINE); | |
176 | } else if (!xen_pcpu_online(info->flags) && | |
177 | xen_pcpu_online(pcpu->flags)) { | |
178 | /* The pcpu is offlined */ | |
179 | pcpu->flags &= ~XEN_PCPU_FLAGS_ONLINE; | |
180 | kobject_uevent(&pcpu->dev.kobj, KOBJ_OFFLINE); | |
181 | } | |
182 | } | |
183 | ||
184 | static struct pcpu *get_pcpu(uint32_t cpu_id) | |
185 | { | |
186 | struct pcpu *pcpu; | |
187 | ||
188 | list_for_each_entry(pcpu, &xen_pcpus, list) { | |
189 | if (pcpu->cpu_id == cpu_id) | |
190 | return pcpu; | |
191 | } | |
192 | ||
193 | return NULL; | |
194 | } | |
195 | ||
196 | static void pcpu_release(struct device *dev) | |
197 | { | |
198 | struct pcpu *pcpu = container_of(dev, struct pcpu, dev); | |
199 | ||
200 | list_del(&pcpu->list); | |
201 | kfree(pcpu); | |
202 | } | |
203 | ||
204 | static void unregister_and_remove_pcpu(struct pcpu *pcpu) | |
205 | { | |
206 | struct device *dev; | |
207 | ||
208 | if (!pcpu) | |
209 | return; | |
210 | ||
211 | dev = &pcpu->dev; | |
f65c9bb3 LJ |
212 | /* pcpu remove would be implicitly done */ |
213 | device_unregister(dev); | |
214 | } | |
215 | ||
216 | static int register_pcpu(struct pcpu *pcpu) | |
217 | { | |
218 | struct device *dev; | |
219 | int err = -EINVAL; | |
220 | ||
221 | if (!pcpu) | |
222 | return err; | |
223 | ||
224 | dev = &pcpu->dev; | |
225 | dev->bus = &xen_pcpu_subsys; | |
226 | dev->id = pcpu->cpu_id; | |
227 | dev->release = pcpu_release; | |
4644e5ab | 228 | dev->groups = pcpu_dev_groups; |
f65c9bb3 LJ |
229 | |
230 | err = device_register(dev); | |
231 | if (err) { | |
da36a2a7 | 232 | put_device(dev); |
f65c9bb3 LJ |
233 | return err; |
234 | } | |
235 | ||
f65c9bb3 LJ |
236 | return 0; |
237 | } | |
238 | ||
239 | static struct pcpu *create_and_register_pcpu(struct xenpf_pcpuinfo *info) | |
240 | { | |
241 | struct pcpu *pcpu; | |
242 | int err; | |
243 | ||
244 | if (info->flags & XEN_PCPU_FLAGS_INVALID) | |
245 | return ERR_PTR(-ENODEV); | |
246 | ||
247 | pcpu = kzalloc(sizeof(struct pcpu), GFP_KERNEL); | |
248 | if (!pcpu) | |
249 | return ERR_PTR(-ENOMEM); | |
250 | ||
251 | INIT_LIST_HEAD(&pcpu->list); | |
252 | pcpu->cpu_id = info->xen_cpuid; | |
073828e9 | 253 | pcpu->acpi_id = info->acpi_id; |
f65c9bb3 LJ |
254 | pcpu->flags = info->flags; |
255 | ||
256 | /* Need hold on xen_pcpu_lock before pcpu list manipulations */ | |
257 | list_add_tail(&pcpu->list, &xen_pcpus); | |
258 | ||
259 | err = register_pcpu(pcpu); | |
260 | if (err) { | |
283c0972 | 261 | pr_warn("Failed to register pcpu%u\n", info->xen_cpuid); |
f65c9bb3 LJ |
262 | return ERR_PTR(-ENOENT); |
263 | } | |
264 | ||
265 | return pcpu; | |
266 | } | |
267 | ||
268 | /* | |
269 | * Caller should hold the xen_pcpu_lock | |
270 | */ | |
271 | static int sync_pcpu(uint32_t cpu, uint32_t *max_cpu) | |
272 | { | |
273 | int ret; | |
274 | struct pcpu *pcpu = NULL; | |
275 | struct xenpf_pcpuinfo *info; | |
276 | struct xen_platform_op op = { | |
277 | .cmd = XENPF_get_cpuinfo, | |
278 | .interface_version = XENPF_INTERFACE_VERSION, | |
279 | .u.pcpu_info.xen_cpuid = cpu, | |
280 | }; | |
281 | ||
cfafae94 | 282 | ret = HYPERVISOR_platform_op(&op); |
f65c9bb3 LJ |
283 | if (ret) |
284 | return ret; | |
285 | ||
286 | info = &op.u.pcpu_info; | |
287 | if (max_cpu) | |
288 | *max_cpu = info->max_present; | |
289 | ||
290 | pcpu = get_pcpu(cpu); | |
291 | ||
292 | /* | |
293 | * Only those at cpu present map has its sys interface. | |
294 | */ | |
295 | if (info->flags & XEN_PCPU_FLAGS_INVALID) { | |
4f8c8527 | 296 | unregister_and_remove_pcpu(pcpu); |
f65c9bb3 LJ |
297 | return 0; |
298 | } | |
299 | ||
300 | if (!pcpu) { | |
301 | pcpu = create_and_register_pcpu(info); | |
302 | if (IS_ERR_OR_NULL(pcpu)) | |
303 | return -ENODEV; | |
304 | } else | |
305 | pcpu_online_status(info, pcpu); | |
306 | ||
307 | return 0; | |
308 | } | |
309 | ||
310 | /* | |
311 | * Sync dom0's pcpu information with xen hypervisor's | |
312 | */ | |
313 | static int xen_sync_pcpus(void) | |
314 | { | |
315 | /* | |
316 | * Boot cpu always have cpu_id 0 in xen | |
317 | */ | |
318 | uint32_t cpu = 0, max_cpu = 0; | |
319 | int err = 0; | |
320 | struct pcpu *pcpu, *tmp; | |
321 | ||
322 | mutex_lock(&xen_pcpu_lock); | |
323 | ||
324 | while (!err && (cpu <= max_cpu)) { | |
325 | err = sync_pcpu(cpu, &max_cpu); | |
326 | cpu++; | |
327 | } | |
328 | ||
329 | if (err) | |
330 | list_for_each_entry_safe(pcpu, tmp, &xen_pcpus, list) | |
331 | unregister_and_remove_pcpu(pcpu); | |
332 | ||
333 | mutex_unlock(&xen_pcpu_lock); | |
334 | ||
335 | return err; | |
336 | } | |
337 | ||
338 | static void xen_pcpu_work_fn(struct work_struct *work) | |
339 | { | |
340 | xen_sync_pcpus(); | |
341 | } | |
342 | static DECLARE_WORK(xen_pcpu_work, xen_pcpu_work_fn); | |
343 | ||
344 | static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id) | |
345 | { | |
346 | schedule_work(&xen_pcpu_work); | |
347 | return IRQ_HANDLED; | |
348 | } | |
349 | ||
350 | static int __init xen_pcpu_init(void) | |
351 | { | |
352 | int irq, ret; | |
353 | ||
354 | if (!xen_initial_domain()) | |
355 | return -ENODEV; | |
356 | ||
357 | irq = bind_virq_to_irqhandler(VIRQ_PCPU_STATE, 0, | |
358 | xen_pcpu_interrupt, 0, | |
359 | "xen-pcpu", NULL); | |
360 | if (irq < 0) { | |
283c0972 | 361 | pr_warn("Failed to bind pcpu virq\n"); |
f65c9bb3 LJ |
362 | return irq; |
363 | } | |
364 | ||
365 | ret = subsys_system_register(&xen_pcpu_subsys, NULL); | |
366 | if (ret) { | |
283c0972 | 367 | pr_warn("Failed to register pcpu subsys\n"); |
f65c9bb3 LJ |
368 | goto err1; |
369 | } | |
370 | ||
371 | ret = xen_sync_pcpus(); | |
372 | if (ret) { | |
283c0972 | 373 | pr_warn("Failed to sync pcpu info\n"); |
f65c9bb3 LJ |
374 | goto err2; |
375 | } | |
376 | ||
377 | return 0; | |
378 | ||
379 | err2: | |
380 | bus_unregister(&xen_pcpu_subsys); | |
381 | err1: | |
382 | unbind_from_irqhandler(irq, NULL); | |
383 | return ret; | |
384 | } | |
385 | arch_initcall(xen_pcpu_init); | |
073828e9 RPM |
386 | |
387 | #ifdef CONFIG_ACPI | |
388 | bool __init xen_processor_present(uint32_t acpi_id) | |
389 | { | |
390 | const struct pcpu *pcpu; | |
391 | bool online = false; | |
392 | ||
393 | mutex_lock(&xen_pcpu_lock); | |
394 | list_for_each_entry(pcpu, &xen_pcpus, list) | |
395 | if (pcpu->acpi_id == acpi_id) { | |
396 | online = pcpu->flags & XEN_PCPU_FLAGS_ONLINE; | |
397 | break; | |
398 | } | |
399 | mutex_unlock(&xen_pcpu_lock); | |
400 | ||
401 | return online; | |
402 | } | |
403 | #endif |