drivers/xen/mcelog.c

   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(&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
  94 static 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
 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(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
 136 out:
 137         mutex_unlock(&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(file, &xen_mce_chrdev_wait, 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                         (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         uint32_t i;
 226
 227         mic = NULL;
 228         x86_mcinfo_lookup(&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         m.mcgcap = g_physinfo[i].mc_msrvalues[__MC_MSR_MCGCAP].value;
 252
 253         mic = NULL;
 254         x86_mcinfo_lookup(&mic, mi, MC_TYPE_BANK);
 255         if (unlikely(!mic)) {
 256                 pr_warn("Fail to find bank error info\n");
 257                 return -ENODEV;
 258         }
 259
 260         do {
 261                 if ((!mic) || (mic->size == 0) ||
 262                     (mic->type != MC_TYPE_GLOBAL   &&
 263                      mic->type != MC_TYPE_BANK     &&
 264                      mic->type != MC_TYPE_EXTENDED &&
 265                      mic->type != MC_TYPE_RECOVERY))
 266                         break;
 267
 268                 if (mic->type == MC_TYPE_BANK) {
 269                         mc_bank = (struct mcinfo_bank *)mic;
 270                         m.misc = mc_bank->mc_misc;
 271                         m.status = mc_bank->mc_status;
 272                         m.addr = mc_bank->mc_addr;
 273                         m.tsc = mc_bank->mc_tsc;
 274                         m.bank = mc_bank->mc_bank;
 275                         m.finished = 1;
 276                         /*log this record*/
 277                         xen_mce_log(&m);
 278                 }
 279                 mic = x86_mcinfo_next(mic);
 280         } while (1);
 281
 282         return 0;
 283 }
 284
 285 static int mc_queue_handle(uint32_t flags)
 286 {
 287         struct xen_mc mc_op;
 288         int ret = 0;
 289
 290         mc_op.cmd = XEN_MC_fetch;
 291         set_xen_guest_handle(mc_op.u.mc_fetch.data, &g_mi);
 292         do {
 293                 mc_op.u.mc_fetch.flags = flags;
 294                 ret = HYPERVISOR_mca(&mc_op);
 295                 if (ret) {
 296                         pr_err("Failed to fetch %surgent error log\n",
 297                                flags == XEN_MC_URGENT ? "" : "non");
 298                         break;
 299                 }
 300
 301                 if (mc_op.u.mc_fetch.flags & XEN_MC_NODATA ||
 302                     mc_op.u.mc_fetch.flags & XEN_MC_FETCHFAILED)
 303                         break;
 304                 else {
 305                         ret = convert_log(&g_mi);
 306                         if (ret)
 307                                 pr_warn("Failed to convert this error log, continue acking it anyway\n");
 308
 309                         mc_op.u.mc_fetch.flags = flags | XEN_MC_ACK;
 310                         ret = HYPERVISOR_mca(&mc_op);
 311                         if (ret) {
 312                                 pr_err("Failed to ack previous error log\n");
 313                                 break;
 314                         }
 315                 }
 316         } while (1);
 317
 318         return ret;
 319 }
 320
 321 /* virq handler for machine check error info*/
 322 static void xen_mce_work_fn(struct work_struct *work)
 323 {
 324         int err;
 325
 326         mutex_lock(&mcelog_lock);
 327
 328         /* urgent mc_info */
 329         err = mc_queue_handle(XEN_MC_URGENT);
 330         if (err)
 331                 pr_err("Failed to handle urgent mc_info queue, continue handling nonurgent mc_info queue anyway\n");
 332
 333         /* nonurgent mc_info */
 334         err = mc_queue_handle(XEN_MC_NONURGENT);
 335         if (err)
 336                 pr_err("Failed to handle nonurgent mc_info queue\n");
 337
 338         /* wake processes polling /dev/mcelog */
 339         wake_up_interruptible(&xen_mce_chrdev_wait);
 340
 341         mutex_unlock(&mcelog_lock);
 342 }
 343 static DECLARE_WORK(xen_mce_work, xen_mce_work_fn);
 344
 345 static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
 346 {
 347         schedule_work(&xen_mce_work);
 348         return IRQ_HANDLED;
 349 }
 350
 351 static int bind_virq_for_mce(void)
 352 {
 353         int ret;
 354         struct xen_mc mc_op;
 355
 356         memset(&mc_op, 0, sizeof(struct xen_mc));
 357
 358         /* Fetch physical CPU Numbers */
 359         mc_op.cmd = XEN_MC_physcpuinfo;
 360         set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
 361         ret = HYPERVISOR_mca(&mc_op);
 362         if (ret) {
 363                 pr_err("Failed to get CPU numbers\n");
 364                 return ret;
 365         }
 366
 367         /* Fetch each CPU Physical Info for later reference*/
 368         ncpus = mc_op.u.mc_physcpuinfo.ncpus;
 369         g_physinfo = kcalloc(ncpus, sizeof(struct mcinfo_logical_cpu),
 370                              GFP_KERNEL);
 371         if (!g_physinfo)
 372                 return -ENOMEM;
 373         set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
 374         ret = HYPERVISOR_mca(&mc_op);
 375         if (ret) {
 376                 pr_err("Failed to get CPU info\n");
 377                 kfree(g_physinfo);
 378                 return ret;
 379         }
 380
 381         ret  = bind_virq_to_irqhandler(VIRQ_MCA, 0,
 382                                        xen_mce_interrupt, 0, "mce", NULL);
 383         if (ret < 0) {
 384                 pr_err("Failed to bind virq\n");
 385                 kfree(g_physinfo);
 386                 return ret;
 387         }
 388
 389         return 0;
 390 }
 391
 392 static int __init xen_late_init_mcelog(void)
 393 {
 394         int ret;
 395
 396         /* Only DOM0 is responsible for MCE logging */
 397         if (!xen_initial_domain())
 398                 return -ENODEV;
 399
 400         /* register character device /dev/mcelog for xen mcelog */
 401         ret = misc_register(&xen_mce_chrdev_device);
 402         if (ret)
 403                 return ret;
 404
 405         ret = bind_virq_for_mce();
 406         if (ret)
 407                 goto deregister;
 408
 409         pr_info("/dev/mcelog registered by Xen\n");
 410
 411         return 0;
 412
 413 deregister:
 414         misc_deregister(&xen_mce_chrdev_device);
 415         return ret;
 416 }
 417 device_initcall(xen_late_init_mcelog);