xen/mce: Add mcelog support for Xen platform

When MCA error occurs, it would be handled by Xen hypervisor first,
and then the error information would be sent to initial domain for logging.

This patch gets error information from Xen hypervisor and convert
Xen format error into Linux format mcelog. This logic is basically
self-contained, not touching other kernel components.

By using tools like mcelog tool users could read specific error information,
like what they did under native Linux.

To test follow directions outlined in Documentation/acpi/apei/einj.txt

Acked-and-tested-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: Ke, Liping <liping.ke@intel.com>
Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Liu, Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

3 files changed, 401 insertions, 0 deletions

diff --git a/drivers/xen/Kconfig b/drivers/xen/Kconfig
index 8d2501e604dd..d4dffcd52873 100644
--- a/drivers/xen/Kconfig
+++ b/drivers/xen/Kconfig
@@ -196,4 +196,12 @@ config XEN_ACPI_PROCESSOR
           called xen_acpi_processor  If you do not know what to choose, select
           M here. If the CPUFREQ drivers are built in, select Y here.
 
+config XEN_MCE_LOG
+        bool "Xen platform mcelog"
+        depends on XEN_DOM0 && X86_64 && X86_MCE
+        default n
+        help
+          Allow kernel fetching MCE error from Xen platform and
+          converting it into Linux mcelog format for mcelog tools
+
 endmenu
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index fc3488631136..a7870292bc75 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -18,6 +18,7 @@ obj-$(CONFIG_XEN_PVHVM)			+= platform-pci.o
 obj-$(CONFIG_XEN_TMEM)                  += tmem.o
 obj-$(CONFIG_SWIOTLB_XEN)               += swiotlb-xen.o
 obj-$(CONFIG_XEN_DOM0)                  += pci.o acpi.o
+obj-$(CONFIG_XEN_MCE_LOG)               += mcelog.o
 obj-$(CONFIG_XEN_PCIDEV_BACKEND)        += xen-pciback/
 obj-$(CONFIG_XEN_PRIVCMD)               += xen-privcmd.o
 obj-$(CONFIG_XEN_ACPI_PROCESSOR)        += xen-acpi-processor.o
diff --git a/drivers/xen/mcelog.c b/drivers/xen/mcelog.c
new file mode 100644
index 000000000000..72e87d2f1929
--- /dev/null
+++ b/drivers/xen/mcelog.c
@@ -0,0 +1,392 @@
+/******************************************************************************
+ * mcelog.c
+ * Driver for receiving and transferring machine check error infomation
+ *
+ * Copyright (c) 2012 Intel Corporation
+ * Author: Liu, Jinsong <jinsong.liu@intel.com>
+ * Author: Jiang, Yunhong <yunhong.jiang@intel.com>
+ * Author: Ke, Liping <liping.ke@intel.com>
+ *
+ * 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.
+ */
+
+#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 <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>
+
+#define XEN_MCELOG "xen_mcelog: "
+
+static struct mc_info g_mi;
+static struct mcinfo_logical_cpu *g_physinfo;
+static uint32_t ncpus;
+
+static DEFINE_SPINLOCK(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 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;
+
+        spin_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:
+        spin_unlock(&mcelog_lock);
+
+        return err ? err : buf - ubuf;
+}
+
+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,
+        .unlocked_ioctl         = xen_mce_chrdev_ioctl,
+        .llseek                 = no_llseek,
+};
+
+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;
+        uint32_t i;
+
+        mic = NULL;
+        x86_mcinfo_lookup(&mic, mi, MC_TYPE_GLOBAL);
+        if (unlikely(!mic)) {
+                pr_warning(XEN_MCELOG "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_warning(XEN_MCELOG "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;
+        m.mcgcap = g_physinfo[i].mc_msrvalues[__MC_MSR_MCGCAP].value;
+
+        mic = NULL;
+        x86_mcinfo_lookup(&mic, mi, MC_TYPE_BANK);
+        if (unlikely(!mic)) {
+                pr_warning(XEN_MCELOG "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;
+        mc_op.interface_version = XEN_MCA_INTERFACE_VERSION;
+        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(XEN_MCELOG "Failed to fetch %s error log\n",
+                               (flags == XEN_MC_URGENT) ?
+                               "urgnet" : "nonurgent");
+                        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_warning(XEN_MCELOG
+                                           "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(XEN_MCELOG
+                                       "Failed to ack previous error log\n");
+                                break;
+                        }
+                }
+        } while (1);
+
+        return ret;
+}
+
+/* virq handler for machine check error info*/
+static irqreturn_t xen_mce_interrupt(int irq, void *dev_id)
+{
+        int err;
+        unsigned long tmp;
+
+        spin_lock_irqsave(&mcelog_lock, tmp);
+
+        /* urgent mc_info */
+        err = mc_queue_handle(XEN_MC_URGENT);
+        if (err)
+                pr_err(XEN_MCELOG
+                       "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(XEN_MCELOG
+                       "Failed to handle nonurgent mc_info queue.\n");
+
+        spin_unlock_irqrestore(&mcelog_lock, tmp);
+
+        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;
+        mc_op.interface_version = XEN_MCA_INTERFACE_VERSION;
+        set_xen_guest_handle(mc_op.u.mc_physcpuinfo.info, g_physinfo);
+        ret = HYPERVISOR_mca(&mc_op);
+        if (ret) {
+                pr_err(XEN_MCELOG "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(XEN_MCELOG "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(XEN_MCELOG "Failed to bind virq\n");
+                kfree(g_physinfo);
+                return ret;
+        }
+
+        return 0;
+}
+
+static int __init xen_late_init_mcelog(void)
+{
+        /* Only DOM0 is responsible for MCE logging */
+        if (xen_initial_domain()) {
+                /* register character device /dev/mcelog for xen mcelog */
+                if (misc_register(&xen_mce_chrdev_device))
+                        return -ENODEV;
+                return bind_virq_for_mce();
+        }
+
+        return -ENODEV;
+}
+device_initcall(xen_late_init_mcelog);