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1/******************************************************************************
2 * mcelog.c
3 * Driver for receiving and transferring machine check error infomation
4 *
5 * Copyright (c) 2012 Intel Corporation
6 * Author: Liu, Jinsong <jinsong.liu@intel.com>
7 * Author: Jiang, Yunhong <yunhong.jiang@intel.com>
8 * Author: Ke, Liping <liping.ke@intel.com>
9 *
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License version 2
12 * as published by the Free Software Foundation; or, when distributed
13 * separately from the Linux kernel or incorporated into other
14 * software packages, subject to the following license:
15 *
16 * Permission is hereby granted, free of charge, to any person obtaining a copy
17 * of this source file (the "Software"), to deal in the Software without
18 * restriction, including without limitation the rights to use, copy, modify,
19 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
20 * and to permit persons to whom the Software is furnished to do so, subject to
21 * the following conditions:
22 *
23 * The above copyright notice and this permission notice shall be included in
24 * all copies or substantial portions of the Software.
25 *
26 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
27 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
28 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
29 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
30 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
31 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
32 * IN THE SOFTWARE.
33 */
34
35#define pr_fmt(fmt) "xen_mcelog: " fmt
36
37#include <linux/init.h>
38#include <linux/types.h>
39#include <linux/kernel.h>
40#include <linux/slab.h>
41#include <linux/fs.h>
42#include <linux/device.h>
43#include <linux/miscdevice.h>
44#include <linux/uaccess.h>
45#include <linux/capability.h>
46#include <linux/poll.h>
47#include <linux/sched.h>
48
49#include <xen/interface/xen.h>
50#include <xen/events.h>
51#include <xen/interface/vcpu.h>
52#include <xen/xen.h>
53#include <asm/xen/hypercall.h>
54#include <asm/xen/hypervisor.h>
55
56static struct mc_info g_mi;
57static struct mcinfo_logical_cpu *g_physinfo;
58static uint32_t ncpus;
59
60static DEFINE_MUTEX(mcelog_lock);
61
62static struct xen_mce_log xen_mcelog = {
63 .signature = XEN_MCE_LOG_SIGNATURE,
64 .len = XEN_MCE_LOG_LEN,
65 .recordlen = sizeof(struct xen_mce),
66};
67
68static DEFINE_SPINLOCK(xen_mce_chrdev_state_lock);
69static int xen_mce_chrdev_open_count; /* #times opened */
70static int xen_mce_chrdev_open_exclu; /* already open exclusive? */
71
72static DECLARE_WAIT_QUEUE_HEAD(xen_mce_chrdev_wait);
73
74static int xen_mce_chrdev_open(struct inode *inode, struct file *file)
75{
76 spin_lock(&xen_mce_chrdev_state_lock);
77
78 if (xen_mce_chrdev_open_exclu ||
79 (xen_mce_chrdev_open_count && (file->f_flags & O_EXCL))) {
80 spin_unlock(&xen_mce_chrdev_state_lock);
81
82 return -EBUSY;
83 }
84
85 if (file->f_flags & O_EXCL)
86 xen_mce_chrdev_open_exclu = 1;
87 xen_mce_chrdev_open_count++;
88
89 spin_unlock(&xen_mce_chrdev_state_lock);
90
91 return nonseekable_open(inode, file);
92}
93
94static int xen_mce_chrdev_release(struct inode *inode, struct file *file)
95{
96 spin_lock(&xen_mce_chrdev_state_lock);
97
98 xen_mce_chrdev_open_count--;
99 xen_mce_chrdev_open_exclu = 0;
100
101 spin_unlock(&xen_mce_chrdev_state_lock);
102
103 return 0;
104}
105
106static ssize_t xen_mce_chrdev_read(struct file *filp, char __user *ubuf,
107 size_t usize, loff_t *off)
108{
109 char __user *buf = ubuf;
110 unsigned num;
111 int i, err;
112
113 mutex_lock(&mcelog_lock);
114
115 num = xen_mcelog.next;
116
117 /* Only supports full reads right now */
118 err = -EINVAL;
119 if (*off != 0 || usize < XEN_MCE_LOG_LEN*sizeof(struct xen_mce))
120 goto out;
121
122 err = 0;
123 for (i = 0; i < num; i++) {
124 struct xen_mce *m = &xen_mcelog.entry[i];
125
126 err |= copy_to_user(buf, m, sizeof(*m));
127 buf += sizeof(*m);
128 }
129
130 memset(xen_mcelog.entry, 0, num * sizeof(struct xen_mce));
131 xen_mcelog.next = 0;
132
133 if (err)
134 err = -EFAULT;
135
136out:
137 mutex_unlock(&mcelog_lock);
138
139 return err ? err : buf - ubuf;
140}
141
142static __poll_t xen_mce_chrdev_poll(struct file *file, poll_table *wait)
143{
144 poll_wait(file, &xen_mce_chrdev_wait, wait);
145
146 if (xen_mcelog.next)
147 return EPOLLIN | EPOLLRDNORM;
148
149 return 0;
150}
151
152static long xen_mce_chrdev_ioctl(struct file *f, unsigned int cmd,
153 unsigned long arg)
154{
155 int __user *p = (int __user *)arg;
156
157 if (!capable(CAP_SYS_ADMIN))
158 return -EPERM;
159
160 switch (cmd) {
161 case MCE_GET_RECORD_LEN:
162 return put_user(sizeof(struct xen_mce), p);
163 case MCE_GET_LOG_LEN:
164 return put_user(XEN_MCE_LOG_LEN, p);
165 case MCE_GETCLEAR_FLAGS: {
166 unsigned flags;
167
168 do {
169 flags = xen_mcelog.flags;
170 } while (cmpxchg(&xen_mcelog.flags, flags, 0) != flags);
171
172 return put_user(flags, p);
173 }
174 default:
175 return -ENOTTY;
176 }
177}
178
179static const struct file_operations xen_mce_chrdev_ops = {
180 .open = xen_mce_chrdev_open,
181 .release = xen_mce_chrdev_release,
182 .read = xen_mce_chrdev_read,
183 .poll = xen_mce_chrdev_poll,
184 .unlocked_ioctl = xen_mce_chrdev_ioctl,
185};
186
187static struct miscdevice xen_mce_chrdev_device = {
188 MISC_MCELOG_MINOR,
189 "mcelog",
190 &xen_mce_chrdev_ops,
191};
192
193/*
194 * Caller should hold the mcelog_lock
195 */
196static void xen_mce_log(struct xen_mce *mce)
197{
198 unsigned entry;
199
200 entry = xen_mcelog.next;
201
202 /*
203 * When the buffer fills up discard new entries.
204 * Assume that the earlier errors are the more
205 * interesting ones:
206 */
207 if (entry >= XEN_MCE_LOG_LEN) {
208 set_bit(XEN_MCE_OVERFLOW,
209 (unsigned long *)&xen_mcelog.flags);
210 return;
211 }
212
213 memcpy(xen_mcelog.entry + entry, mce, sizeof(struct xen_mce));
214
215 xen_mcelog.next++;
216}
217
218static int convert_log(struct mc_info *mi)
219{
220 struct mcinfo_common *mic;
221 struct mcinfo_global *mc_global;
222 struct mcinfo_bank *mc_bank;
223 struct xen_mce m;
224 unsigned int i, j;
225
226 mic = NULL;
227 x86_mcinfo_lookup(&mic, mi, MC_TYPE_GLOBAL);
228 if (unlikely(!mic)) {
229 pr_warn("Failed to find global error info\n");
230 return -ENODEV;
231 }
232
233 memset(&m, 0, sizeof(struct xen_mce));
234
235 mc_global = (struct mcinfo_global *)mic;
236 m.mcgstatus = mc_global->mc_gstatus;
237 m.apicid = mc_global->mc_apicid;
238
239 for (i = 0; i < ncpus; i++)
240 if (g_physinfo[i].mc_apicid == m.apicid)
241 break;
242 if (unlikely(i == ncpus)) {
243 pr_warn("Failed to match cpu with apicid %d\n", m.apicid);
244 return -ENODEV;
245 }
246
247 m.socketid = g_physinfo[i].mc_chipid;
248 m.cpu = m.extcpu = g_physinfo[i].mc_cpunr;
249 m.cpuvendor = (__u8)g_physinfo[i].mc_vendor;
250 for (j = 0; j < g_physinfo[i].mc_nmsrvals; ++j)
251 switch (g_physinfo[i].mc_msrvalues[j].reg) {
252 case MSR_IA32_MCG_CAP:
253 m.mcgcap = g_physinfo[i].mc_msrvalues[j].value;
254 break;
255
256 case MSR_PPIN:
257 case MSR_AMD_PPIN:
258 m.ppin = g_physinfo[i].mc_msrvalues[j].value;
259 break;
260 }
261
262 mic = NULL;
263 x86_mcinfo_lookup(&mic, mi, MC_TYPE_BANK);
264 if (unlikely(!mic)) {
265 pr_warn("Fail to find bank error info\n");
266 return -ENODEV;
267 }
268
269 do {
270 if ((!mic) || (mic->size == 0) ||
271 (mic->type != MC_TYPE_GLOBAL &&
272 mic->type != MC_TYPE_BANK &&
273 mic->type != MC_TYPE_EXTENDED &&
274 mic->type != MC_TYPE_RECOVERY))
275 break;
276
277 if (mic->type == MC_TYPE_BANK) {
278 mc_bank = (struct mcinfo_bank *)mic;
279 m.misc = mc_bank->mc_misc;
280 m.status = mc_bank->mc_status;
281 m.addr = mc_bank->mc_addr;
282 m.tsc = mc_bank->mc_tsc;
283 m.bank = mc_bank->mc_bank;
284 m.finished = 1;
285 /*log this record*/
286 xen_mce_log(&m);
287 }
288 mic = x86_mcinfo_next(mic);
289 } while (1);
290
291 return 0;
292}
293
294static int mc_queue_handle(uint32_t flags)
295{
296 struct xen_mc mc_op;
297 int ret = 0;
298
299 mc_op.cmd = XEN_MC_fetch;
300 set_xen_guest_handle(mc_op.u.mc_fetch.data, &g_mi);
301 do {
302 mc_op.u.mc_fetch.flags = flags;
303 ret = HYPERVISOR_mca(&mc_op);
304 if (ret) {
305 pr_err("Failed to fetch %surgent error log\n",
306 flags == XEN_MC_URGENT ? "" : "non");
307 break;
308 }
309
310 if (mc_op.u.mc_fetch.flags & XEN_MC_NODATA ||
311 mc_op.u.mc_fetch.flags & XEN_MC_FETCHFAILED)
312 break;
313 else {
314 ret = convert_log(&g_mi);
315 if (ret)
316 pr_warn("Failed to convert this error log, continue acking it anyway\n");
317
318 mc_op.u.mc_fetch.flags = flags | XEN_MC_ACK;
319 ret = HYPERVISOR_mca(&mc_op);
320 if (ret) {
321 pr_err("Failed to ack previous error log\n");
322 break;
323 }
324 }
325 } while (1);
326
327 return ret;
328}
329
330/* virq handler for machine check error info*/
331static void xen_mce_work_fn(struct work_struct *work)
332{
333 int err;
334
335 mutex_lock(&mcelog_lock);
336
337 /* urgent mc_info */
338 err = mc_queue_handle(XEN_MC_URGENT);
339 if (err)
340 pr_err("Failed to handle urgent mc_info queue, continue handling nonurgent mc_info queue anyway\n");
341
342 /* nonurgent mc_info */
343 err = mc_queue_handle(XEN_MC_NONURGENT);
344 if (err)
345 pr_err("Failed to handle nonurgent mc_info queue\n");
346
347 /* wake processes polling /dev/mcelog */
348 wake_up_interruptible(&xen_mce_chrdev_wait);
349
350 mutex_unlock(&mcelog_lock);
351}
352static DECLARE_WORK(xen_mce_work, xen_mce_work_fn);
353
354static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
355{
356 schedule_work(&xen_mce_work);
357 return IRQ_HANDLED;
358}
359
360static int bind_virq_for_mce(void)
361{
362 int ret;
363 struct xen_mc mc_op;
364
365 memset(&mc_op, 0, sizeof(struct xen_mc));
366
367 /* Fetch physical CPU Numbers */
368 mc_op.cmd = XEN_MC_physcpuinfo;
369 set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
370 ret = HYPERVISOR_mca(&mc_op);
371 if (ret) {
372 pr_err("Failed to get CPU numbers\n");
373 return ret;
374 }
375
376 /* Fetch each CPU Physical Info for later reference*/
377 ncpus = mc_op.u.mc_physcpuinfo.ncpus;
378 g_physinfo = kcalloc(ncpus, sizeof(struct mcinfo_logical_cpu),
379 GFP_KERNEL);
380 if (!g_physinfo)
381 return -ENOMEM;
382 set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
383 ret = HYPERVISOR_mca(&mc_op);
384 if (ret) {
385 pr_err("Failed to get CPU info\n");
386 kfree(g_physinfo);
387 return ret;
388 }
389
390 ret = bind_virq_to_irqhandler(VIRQ_MCA, 0,
391 xen_mce_interrupt, 0, "mce", NULL);
392 if (ret < 0) {
393 pr_err("Failed to bind virq\n");
394 kfree(g_physinfo);
395 return ret;
396 }
397
398 return 0;
399}
400
401static int __init xen_late_init_mcelog(void)
402{
403 int ret;
404
405 /* Only DOM0 is responsible for MCE logging */
406 if (!xen_initial_domain())
407 return -ENODEV;
408
409 /* register character device /dev/mcelog for xen mcelog */
410 ret = misc_register(&xen_mce_chrdev_device);
411 if (ret)
412 return ret;
413
414 ret = bind_virq_for_mce();
415 if (ret)
416 goto deregister;
417
418 pr_info("/dev/mcelog registered by Xen\n");
419
420 return 0;
421
422deregister:
423 misc_deregister(&xen_mce_chrdev_device);
424 return ret;
425}
426device_initcall(xen_late_init_mcelog);