/******************************************************************************
* mcelog.c
* Driver for receiving and transferring machine check error infomation
*
* Copyright (c) 2012 Intel Corporation
* Author: Liu, Jinsong <[email protected]>
* Author: Jiang, Yunhong <[email protected]>
* Author: Ke, Liping <[email protected]>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#define pr_fmt(fmt) "xen_mcelog: " fmt
#include <linux/init.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/fs.h>
#include <linux/device.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/capability.h>
#include <linux/poll.h>
#include <linux/sched.h>
#include <xen/interface/xen.h>
#include <xen/events.h>
#include <xen/interface/vcpu.h>
#include <xen/xen.h>
#include <asm/xen/hypercall.h>
#include <asm/xen/hypervisor.h>
static struct mc_info g_mi;
static struct mcinfo_logical_cpu *g_physinfo;
static uint32_t ncpus;
static DEFINE_MUTEX(mcelog_lock);
static struct xen_mce_log xen_mcelog = {
.signature = XEN_MCE_LOG_SIGNATURE,
.len = XEN_MCE_LOG_LEN,
.recordlen = sizeof(struct xen_mce),
};
static DEFINE_SPINLOCK(xen_mce_chrdev_state_lock);
static int xen_mce_chrdev_open_count; /* #times opened */
static int xen_mce_chrdev_open_exclu; /* already open exclusive? */
static DECLARE_WAIT_QUEUE_HEAD(xen_mce_chrdev_wait);
static int xen_mce_chrdev_open(struct inode *inode, struct file *file)
{
spin_lock(&xen_mce_chrdev_state_lock);
if (xen_mce_chrdev_open_exclu ||
(xen_mce_chrdev_open_count && (file->f_flags & O_EXCL))) {
spin_unlock(&xen_mce_chrdev_state_lock);
return -EBUSY;
}
if (file->f_flags & O_EXCL)
xen_mce_chrdev_open_exclu = 1;
xen_mce_chrdev_open_count++;
spin_unlock(&xen_mce_chrdev_state_lock);
return nonseekable_open(inode, file);
}
static int xen_mce_chrdev_release(struct inode *inode, struct file *file)
{
spin_lock(&xen_mce_chrdev_state_lock);
xen_mce_chrdev_open_count--;
xen_mce_chrdev_open_exclu = 0;
spin_unlock(&xen_mce_chrdev_state_lock);
return 0;
}
static ssize_t xen_mce_chrdev_read(struct file *filp, char __user *ubuf,
size_t usize, loff_t *off)
{
char __user *buf = ubuf;
unsigned num;
int i, err;
mutex_lock(&mcelog_lock);
num = xen_mcelog.next;
/* Only supports full reads right now */
err = -EINVAL;
if (*off != 0 || usize < XEN_MCE_LOG_LEN*sizeof(struct xen_mce))
goto out;
err = 0;
for (i = 0; i < num; i++) {
struct xen_mce *m = &xen_mcelog.entry[i];
err |= copy_to_user(buf, m, sizeof(*m));
buf += sizeof(*m);
}
memset(xen_mcelog.entry, 0, num * sizeof(struct xen_mce));
xen_mcelog.next = 0;
if (err)
err = -EFAULT;
out:
mutex_unlock(&mcelog_lock);
return err ? err : buf - ubuf;
}
static __poll_t xen_mce_chrdev_poll(struct file *file, poll_table *wait)
{
poll_wait(file, &xen_mce_chrdev_wait, wait);
if (xen_mcelog.next)
return EPOLLIN | EPOLLRDNORM;
return 0;
}
static long xen_mce_chrdev_ioctl(struct file *f, unsigned int cmd,
unsigned long arg)
{
int __user *p = (int __user *)arg;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
switch (cmd) {
case MCE_GET_RECORD_LEN:
return put_user(sizeof(struct xen_mce), p);
case MCE_GET_LOG_LEN:
return put_user(XEN_MCE_LOG_LEN, p);
case MCE_GETCLEAR_FLAGS: {
unsigned flags;
do {
flags = xen_mcelog.flags;
} while (cmpxchg(&xen_mcelog.flags, flags, 0) != flags);
return put_user(flags, p);
}
default:
return -ENOTTY;
}
}
static const struct file_operations xen_mce_chrdev_ops = {
.open = xen_mce_chrdev_open,
.release = xen_mce_chrdev_release,
.read = xen_mce_chrdev_read,
.poll = xen_mce_chrdev_poll,
.unlocked_ioctl = xen_mce_chrdev_ioctl,
};
static struct miscdevice xen_mce_chrdev_device = {
MISC_MCELOG_MINOR,
"mcelog",
&xen_mce_chrdev_ops,
};
/*
* Caller should hold the mcelog_lock
*/
static void xen_mce_log(struct xen_mce *mce)
{
unsigned entry;
entry = xen_mcelog.next;
/*
* When the buffer fills up discard new entries.
* Assume that the earlier errors are the more
* interesting ones:
*/
if (entry >= XEN_MCE_LOG_LEN) {
set_bit(XEN_MCE_OVERFLOW,
(unsigned long *)&xen_mcelog.flags);
return;
}
memcpy(xen_mcelog.entry + entry, mce, sizeof(struct xen_mce));
xen_mcelog.next++;
}
static int convert_log(struct mc_info *mi)
{
struct mcinfo_common *mic;
struct mcinfo_global *mc_global;
struct mcinfo_bank *mc_bank;
struct xen_mce m;
unsigned int i, j;
mic = NULL;
x86_mcinfo_lookup(&mic, mi, MC_TYPE_GLOBAL);
if (unlikely(!mic)) {
pr_warn("Failed to find global error info\n");
return -ENODEV;
}
memset(&m, 0, sizeof(struct xen_mce));
mc_global = (struct mcinfo_global *)mic;
m.mcgstatus = mc_global->mc_gstatus;
m.apicid = mc_global->mc_apicid;
for (i = 0; i < ncpus; i++)
if (g_physinfo[i].mc_apicid == m.apicid)
break;
if (unlikely(i == ncpus)) {
pr_warn("Failed to match cpu with apicid %d\n", m.apicid);
return -ENODEV;
}
m.socketid = g_physinfo[i].mc_chipid;
m.cpu = m.extcpu = g_physinfo[i].mc_cpunr;
m.cpuvendor = (__u8)g_physinfo[i].mc_vendor;
for (j = 0; j < g_physinfo[i].mc_nmsrvals; ++j)
switch (g_physinfo[i].mc_msrvalues[j].reg) {
case MSR_IA32_MCG_CAP:
m.mcgcap = g_physinfo[i].mc_msrvalues[j].value;
break;
case MSR_PPIN:
case MSR_AMD_PPIN:
m.ppin = g_physinfo[i].mc_msrvalues[j].value;
break;
}
mic = NULL;
x86_mcinfo_lookup(&mic, mi, MC_TYPE_BANK);
if (unlikely(!mic)) {
pr_warn("Fail to find bank error info\n");
return -ENODEV;
}
do {
if ((!mic) || (mic->size == 0) ||
(mic->type != MC_TYPE_GLOBAL &&
mic->type != MC_TYPE_BANK &&
mic->type != MC_TYPE_EXTENDED &&
mic->type != MC_TYPE_RECOVERY))
break;
if (mic->type == MC_TYPE_BANK) {
mc_bank = (struct mcinfo_bank *)mic;
m.misc = mc_bank->mc_misc;
m.status = mc_bank->mc_status;
m.addr = mc_bank->mc_addr;
m.tsc = mc_bank->mc_tsc;
m.bank = mc_bank->mc_bank;
m.finished = 1;
/*log this record*/
xen_mce_log(&m);
}
mic = x86_mcinfo_next(mic);
} while (1);
return 0;
}
static int mc_queue_handle(uint32_t flags)
{
struct xen_mc mc_op;
int ret = 0;
mc_op.cmd = XEN_MC_fetch;
set_xen_guest_handle(mc_op.u.mc_fetch.data, &g_mi);
do {
mc_op.u.mc_fetch.flags = flags;
ret = HYPERVISOR_mca(&mc_op);
if (ret) {
pr_err("Failed to fetch %surgent error log\n",
flags == XEN_MC_URGENT ? "" : "non");
break;
}
if (mc_op.u.mc_fetch.flags & XEN_MC_NODATA ||
mc_op.u.mc_fetch.flags & XEN_MC_FETCHFAILED)
break;
else {
ret = convert_log(&g_mi);
if (ret)
pr_warn("Failed to convert this error log, continue acking it anyway\n");
mc_op.u.mc_fetch.flags = flags | XEN_MC_ACK;
ret = HYPERVISOR_mca(&mc_op);
if (ret) {
pr_err("Failed to ack previous error log\n");
break;
}
}
} while (1);
return ret;
}
/* virq handler for machine check error info*/
static void xen_mce_work_fn(struct work_struct *work)
{
int err;
mutex_lock(&mcelog_lock);
/* urgent mc_info */
err = mc_queue_handle(XEN_MC_URGENT);
if (err)
pr_err("Failed to handle urgent mc_info queue, continue handling nonurgent mc_info queue anyway\n");
/* nonurgent mc_info */
err = mc_queue_handle(XEN_MC_NONURGENT);
if (err)
pr_err("Failed to handle nonurgent mc_info queue\n");
/* wake processes polling /dev/mcelog */
wake_up_interruptible(&xen_mce_chrdev_wait);
mutex_unlock(&mcelog_lock);
}
static DECLARE_WORK(xen_mce_work, xen_mce_work_fn);
static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
{
schedule_work(&xen_mce_work);
return IRQ_HANDLED;
}
static int bind_virq_for_mce(void)
{
int ret;
struct xen_mc mc_op;
memset(&mc_op, 0, sizeof(struct xen_mc));
/* Fetch physical CPU Numbers */
mc_op.cmd = XEN_MC_physcpuinfo;
set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
ret = HYPERVISOR_mca(&mc_op);
if (ret) {
pr_err("Failed to get CPU numbers\n");
return ret;
}
/* Fetch each CPU Physical Info for later reference*/
ncpus = mc_op.u.mc_physcpuinfo.ncpus;
g_physinfo = kcalloc(ncpus, sizeof(struct mcinfo_logical_cpu),
GFP_KERNEL);
if (!g_physinfo)
return -ENOMEM;
set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
ret = HYPERVISOR_mca(&mc_op);
if (ret) {
pr_err("Failed to get CPU info\n");
kfree(g_physinfo);
return ret;
}
ret = bind_virq_to_irqhandler(VIRQ_MCA, 0,
xen_mce_interrupt, 0, "mce", NULL);
if (ret < 0) {
pr_err("Failed to bind virq\n");
kfree(g_physinfo);
return ret;
}
return 0;
}
static int __init xen_late_init_mcelog(void)
{
int ret;
/* Only DOM0 is responsible for MCE logging */
if (!xen_initial_domain())
return -ENODEV;
/* register character device /dev/mcelog for xen mcelog */
ret = misc_register(&xen_mce_chrdev_device);
if (ret)
return ret;
ret = bind_virq_for_mce();
if (ret)
goto deregister;
pr_info("/dev/mcelog registered by Xen\n");
return 0;
deregister:
misc_deregister(&xen_mce_chrdev_device);
return ret;
}
device_initcall(xen_late_init_mcelog);
Codebase Browser
linux