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 | |
56 | static struct mc_info g_mi; |
57 | static struct mcinfo_logical_cpu *g_physinfo; |
58 | static uint32_t ncpus; |
59 | |
60 | static DEFINE_MUTEX(mcelog_lock); |
61 | |
62 | static 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 | |
68 | static DEFINE_SPINLOCK(xen_mce_chrdev_state_lock); |
69 | static int xen_mce_chrdev_open_count; /* #times opened */ |
70 | static int xen_mce_chrdev_open_exclu; /* already open exclusive? */ |
71 | |
72 | static DECLARE_WAIT_QUEUE_HEAD(xen_mce_chrdev_wait); |
73 | |
74 | static int xen_mce_chrdev_open(struct inode *inode, struct file *file) |
75 | { |
76 | spin_lock(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(lock: &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(lock: &xen_mce_chrdev_state_lock); |
90 | |
91 | return nonseekable_open(inode, filp: file); |
92 | } |
93 | |
94 | static int xen_mce_chrdev_release(struct inode *inode, struct file *file) |
95 | { |
96 | spin_lock(lock: &xen_mce_chrdev_state_lock); |
97 | |
98 | xen_mce_chrdev_open_count--; |
99 | xen_mce_chrdev_open_exclu = 0; |
100 | |
101 | spin_unlock(lock: &xen_mce_chrdev_state_lock); |
102 | |
103 | return 0; |
104 | } |
105 | |
106 | static 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(to: buf, from: m, n: 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 | |
136 | out: |
137 | mutex_unlock(lock: &mcelog_lock); |
138 | |
139 | return err ? err : buf - ubuf; |
140 | } |
141 | |
142 | static __poll_t xen_mce_chrdev_poll(struct file *file, poll_table *wait) |
143 | { |
144 | poll_wait(filp: file, wait_address: &xen_mce_chrdev_wait, p: wait); |
145 | |
146 | if (xen_mcelog.next) |
147 | return EPOLLIN | EPOLLRDNORM; |
148 | |
149 | return 0; |
150 | } |
151 | |
152 | static 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 | |
179 | static 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 | .llseek = no_llseek, |
186 | }; |
187 | |
188 | static struct miscdevice xen_mce_chrdev_device = { |
189 | MISC_MCELOG_MINOR, |
190 | "mcelog" , |
191 | &xen_mce_chrdev_ops, |
192 | }; |
193 | |
194 | /* |
195 | * Caller should hold the mcelog_lock |
196 | */ |
197 | static void xen_mce_log(struct xen_mce *mce) |
198 | { |
199 | unsigned entry; |
200 | |
201 | entry = xen_mcelog.next; |
202 | |
203 | /* |
204 | * When the buffer fills up discard new entries. |
205 | * Assume that the earlier errors are the more |
206 | * interesting ones: |
207 | */ |
208 | if (entry >= XEN_MCE_LOG_LEN) { |
209 | set_bit(XEN_MCE_OVERFLOW, |
210 | addr: (unsigned long *)&xen_mcelog.flags); |
211 | return; |
212 | } |
213 | |
214 | memcpy(xen_mcelog.entry + entry, mce, sizeof(struct xen_mce)); |
215 | |
216 | xen_mcelog.next++; |
217 | } |
218 | |
219 | static int convert_log(struct mc_info *mi) |
220 | { |
221 | struct mcinfo_common *mic; |
222 | struct mcinfo_global *mc_global; |
223 | struct mcinfo_bank *mc_bank; |
224 | struct xen_mce m; |
225 | unsigned int i, j; |
226 | |
227 | mic = NULL; |
228 | x86_mcinfo_lookup(ret: &mic, mi, MC_TYPE_GLOBAL); |
229 | if (unlikely(!mic)) { |
230 | pr_warn("Failed to find global error info\n" ); |
231 | return -ENODEV; |
232 | } |
233 | |
234 | memset(&m, 0, sizeof(struct xen_mce)); |
235 | |
236 | mc_global = (struct mcinfo_global *)mic; |
237 | m.mcgstatus = mc_global->mc_gstatus; |
238 | m.apicid = mc_global->mc_apicid; |
239 | |
240 | for (i = 0; i < ncpus; i++) |
241 | if (g_physinfo[i].mc_apicid == m.apicid) |
242 | break; |
243 | if (unlikely(i == ncpus)) { |
244 | pr_warn("Failed to match cpu with apicid %d\n" , m.apicid); |
245 | return -ENODEV; |
246 | } |
247 | |
248 | m.socketid = g_physinfo[i].mc_chipid; |
249 | m.cpu = m.extcpu = g_physinfo[i].mc_cpunr; |
250 | m.cpuvendor = (__u8)g_physinfo[i].mc_vendor; |
251 | for (j = 0; j < g_physinfo[i].mc_nmsrvals; ++j) |
252 | switch (g_physinfo[i].mc_msrvalues[j].reg) { |
253 | case MSR_IA32_MCG_CAP: |
254 | m.mcgcap = g_physinfo[i].mc_msrvalues[j].value; |
255 | break; |
256 | |
257 | case MSR_PPIN: |
258 | case MSR_AMD_PPIN: |
259 | m.ppin = g_physinfo[i].mc_msrvalues[j].value; |
260 | break; |
261 | } |
262 | |
263 | mic = NULL; |
264 | x86_mcinfo_lookup(ret: &mic, mi, MC_TYPE_BANK); |
265 | if (unlikely(!mic)) { |
266 | pr_warn("Fail to find bank error info\n" ); |
267 | return -ENODEV; |
268 | } |
269 | |
270 | do { |
271 | if ((!mic) || (mic->size == 0) || |
272 | (mic->type != MC_TYPE_GLOBAL && |
273 | mic->type != MC_TYPE_BANK && |
274 | mic->type != MC_TYPE_EXTENDED && |
275 | mic->type != MC_TYPE_RECOVERY)) |
276 | break; |
277 | |
278 | if (mic->type == MC_TYPE_BANK) { |
279 | mc_bank = (struct mcinfo_bank *)mic; |
280 | m.misc = mc_bank->mc_misc; |
281 | m.status = mc_bank->mc_status; |
282 | m.addr = mc_bank->mc_addr; |
283 | m.tsc = mc_bank->mc_tsc; |
284 | m.bank = mc_bank->mc_bank; |
285 | m.finished = 1; |
286 | /*log this record*/ |
287 | xen_mce_log(mce: &m); |
288 | } |
289 | mic = x86_mcinfo_next(mic); |
290 | } while (1); |
291 | |
292 | return 0; |
293 | } |
294 | |
295 | static int mc_queue_handle(uint32_t flags) |
296 | { |
297 | struct xen_mc mc_op; |
298 | int ret = 0; |
299 | |
300 | mc_op.cmd = XEN_MC_fetch; |
301 | set_xen_guest_handle(mc_op.u.mc_fetch.data, &g_mi); |
302 | do { |
303 | mc_op.u.mc_fetch.flags = flags; |
304 | ret = HYPERVISOR_mca(mc_op: &mc_op); |
305 | if (ret) { |
306 | pr_err("Failed to fetch %surgent error log\n" , |
307 | flags == XEN_MC_URGENT ? "" : "non" ); |
308 | break; |
309 | } |
310 | |
311 | if (mc_op.u.mc_fetch.flags & XEN_MC_NODATA || |
312 | mc_op.u.mc_fetch.flags & XEN_MC_FETCHFAILED) |
313 | break; |
314 | else { |
315 | ret = convert_log(mi: &g_mi); |
316 | if (ret) |
317 | pr_warn("Failed to convert this error log, continue acking it anyway\n" ); |
318 | |
319 | mc_op.u.mc_fetch.flags = flags | XEN_MC_ACK; |
320 | ret = HYPERVISOR_mca(mc_op: &mc_op); |
321 | if (ret) { |
322 | pr_err("Failed to ack previous error log\n" ); |
323 | break; |
324 | } |
325 | } |
326 | } while (1); |
327 | |
328 | return ret; |
329 | } |
330 | |
331 | /* virq handler for machine check error info*/ |
332 | static void xen_mce_work_fn(struct work_struct *work) |
333 | { |
334 | int err; |
335 | |
336 | mutex_lock(&mcelog_lock); |
337 | |
338 | /* urgent mc_info */ |
339 | err = mc_queue_handle(XEN_MC_URGENT); |
340 | if (err) |
341 | pr_err("Failed to handle urgent mc_info queue, continue handling nonurgent mc_info queue anyway\n" ); |
342 | |
343 | /* nonurgent mc_info */ |
344 | err = mc_queue_handle(XEN_MC_NONURGENT); |
345 | if (err) |
346 | pr_err("Failed to handle nonurgent mc_info queue\n" ); |
347 | |
348 | /* wake processes polling /dev/mcelog */ |
349 | wake_up_interruptible(&xen_mce_chrdev_wait); |
350 | |
351 | mutex_unlock(lock: &mcelog_lock); |
352 | } |
353 | static DECLARE_WORK(xen_mce_work, xen_mce_work_fn); |
354 | |
355 | static irqreturn_t xen_mce_interrupt(int irq, void *dev_id) |
356 | { |
357 | schedule_work(work: &xen_mce_work); |
358 | return IRQ_HANDLED; |
359 | } |
360 | |
361 | static int bind_virq_for_mce(void) |
362 | { |
363 | int ret; |
364 | struct xen_mc mc_op; |
365 | |
366 | memset(&mc_op, 0, sizeof(struct xen_mc)); |
367 | |
368 | /* Fetch physical CPU Numbers */ |
369 | mc_op.cmd = XEN_MC_physcpuinfo; |
370 | set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo); |
371 | ret = HYPERVISOR_mca(mc_op: &mc_op); |
372 | if (ret) { |
373 | pr_err("Failed to get CPU numbers\n" ); |
374 | return ret; |
375 | } |
376 | |
377 | /* Fetch each CPU Physical Info for later reference*/ |
378 | ncpus = mc_op.u.mc_physcpuinfo.ncpus; |
379 | g_physinfo = kcalloc(n: ncpus, size: sizeof(struct mcinfo_logical_cpu), |
380 | GFP_KERNEL); |
381 | if (!g_physinfo) |
382 | return -ENOMEM; |
383 | set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo); |
384 | ret = HYPERVISOR_mca(mc_op: &mc_op); |
385 | if (ret) { |
386 | pr_err("Failed to get CPU info\n" ); |
387 | kfree(objp: g_physinfo); |
388 | return ret; |
389 | } |
390 | |
391 | ret = bind_virq_to_irqhandler(VIRQ_MCA, cpu: 0, |
392 | handler: xen_mce_interrupt, irqflags: 0, devname: "mce" , NULL); |
393 | if (ret < 0) { |
394 | pr_err("Failed to bind virq\n" ); |
395 | kfree(objp: g_physinfo); |
396 | return ret; |
397 | } |
398 | |
399 | return 0; |
400 | } |
401 | |
402 | static int __init xen_late_init_mcelog(void) |
403 | { |
404 | int ret; |
405 | |
406 | /* Only DOM0 is responsible for MCE logging */ |
407 | if (!xen_initial_domain()) |
408 | return -ENODEV; |
409 | |
410 | /* register character device /dev/mcelog for xen mcelog */ |
411 | ret = misc_register(misc: &xen_mce_chrdev_device); |
412 | if (ret) |
413 | return ret; |
414 | |
415 | ret = bind_virq_for_mce(); |
416 | if (ret) |
417 | goto deregister; |
418 | |
419 | pr_info("/dev/mcelog registered by Xen\n" ); |
420 | |
421 | return 0; |
422 | |
423 | deregister: |
424 | misc_deregister(misc: &xen_mce_chrdev_device); |
425 | return ret; |
426 | } |
427 | device_initcall(xen_late_init_mcelog); |
428 | |