x86_64: move kernel

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 875 insertions, 0 deletions

diff --git a/arch/x86/kernel/mce_64.c b/arch/x86/kernel/mce_64.c
new file mode 100644
index 000000000000..a66d607f5b92
--- /dev/null
+++ b/arch/x86/kernel/mce_64.c
@@ -0,0 +1,875 @@
+/*
+ * Machine check handler.
+ * K8 parts Copyright 2002,2003 Andi Kleen, SuSE Labs.
+ * Rest from unknown author(s). 
+ * 2004 Andi Kleen. Rewrote most of it. 
+ */
+
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/string.h>
+#include <linux/rcupdate.h>
+#include <linux/kallsyms.h>
+#include <linux/sysdev.h>
+#include <linux/miscdevice.h>
+#include <linux/fs.h>
+#include <linux/capability.h>
+#include <linux/cpu.h>
+#include <linux/percpu.h>
+#include <linux/poll.h>
+#include <linux/thread_info.h>
+#include <linux/ctype.h>
+#include <linux/kmod.h>
+#include <linux/kdebug.h>
+#include <asm/processor.h> 
+#include <asm/msr.h>
+#include <asm/mce.h>
+#include <asm/uaccess.h>
+#include <asm/smp.h>
+#include <asm/idle.h>
+
+#define MISC_MCELOG_MINOR 227
+#define NR_BANKS 6
+
+atomic_t mce_entry;
+
+static int mce_dont_init;
+
+/*
+ * Tolerant levels:
+ *   0: always panic on uncorrected errors, log corrected errors
+ *   1: panic or SIGBUS on uncorrected errors, log corrected errors
+ *   2: SIGBUS or log uncorrected errors (if possible), log corrected errors
+ *   3: never panic or SIGBUS, log all errors (for testing only)
+ */
+static int tolerant = 1;
+static int banks;
+static unsigned long bank[NR_BANKS] = { [0 ... NR_BANKS-1] = ~0UL };
+static unsigned long notify_user;
+static int rip_msr;
+static int mce_bootlog = 1;
+static atomic_t mce_events;
+
+static char trigger[128];
+static char *trigger_argv[2] = { trigger, NULL };
+
+static DECLARE_WAIT_QUEUE_HEAD(mce_wait);
+
+/*
+ * Lockless MCE logging infrastructure.
+ * This avoids deadlocks on printk locks without having to break locks. Also
+ * separate MCEs from kernel messages to avoid bogus bug reports.
+ */
+
+struct mce_log mcelog = { 
+	MCE_LOG_SIGNATURE,
+	MCE_LOG_LEN,
+}; 
+
+void mce_log(struct mce *mce)
+{
+	unsigned next, entry;
+	atomic_inc(&mce_events);
+	mce->finished = 0;
+	wmb();
+	for (;;) {
+		entry = rcu_dereference(mcelog.next);
+		/* The rmb forces the compiler to reload next in each
+		    iteration */
+		rmb();
+		for (;;) {
+			/* When the buffer fills up discard new entries. Assume
+			   that the earlier errors are the more interesting. */
+			if (entry >= MCE_LOG_LEN) {
+				set_bit(MCE_OVERFLOW, &mcelog.flags);
+				return;
+			}
+			/* Old left over entry. Skip. */
+			if (mcelog.entry[entry].finished) {
+				entry++;
+				continue;
+			}
+			break;
+		}
+		smp_rmb();
+		next = entry + 1;
+		if (cmpxchg(&mcelog.next, entry, next) == entry)
+			break;
+	}
+	memcpy(mcelog.entry + entry, mce, sizeof(struct mce));
+	wmb();
+	mcelog.entry[entry].finished = 1;
+	wmb();
+
+	set_bit(0, &notify_user);
+}
+
+static void print_mce(struct mce *m)
+{
+	printk(KERN_EMERG "\n"
+	       KERN_EMERG "HARDWARE ERROR\n"
+	       KERN_EMERG
+	       "CPU %d: Machine Check Exception: %16Lx Bank %d: %016Lx\n",
+	       m->cpu, m->mcgstatus, m->bank, m->status);
+	if (m->rip) {
+		printk(KERN_EMERG 
+		       "RIP%s %02x:<%016Lx> ",
+		       !(m->mcgstatus & MCG_STATUS_EIPV) ? " !INEXACT!" : "",
+		       m->cs, m->rip);
+		if (m->cs == __KERNEL_CS)
+			print_symbol("{%s}", m->rip);
+		printk("\n");
+	}
+	printk(KERN_EMERG "TSC %Lx ", m->tsc); 
+	if (m->addr)
+		printk("ADDR %Lx ", m->addr);
+	if (m->misc)
+		printk("MISC %Lx ", m->misc); 	
+	printk("\n");
+	printk(KERN_EMERG "This is not a software problem!\n");
+        printk(KERN_EMERG
+    "Run through mcelog --ascii to decode and contact your hardware vendor\n");
+}
+
+static void mce_panic(char *msg, struct mce *backup, unsigned long start)
+{ 
+	int i;
+
+	oops_begin();
+	for (i = 0; i < MCE_LOG_LEN; i++) {
+		unsigned long tsc = mcelog.entry[i].tsc;
+		if (time_before(tsc, start))
+			continue;
+		print_mce(&mcelog.entry[i]); 
+		if (backup && mcelog.entry[i].tsc == backup->tsc)
+			backup = NULL;
+	}
+	if (backup)
+		print_mce(backup);
+	panic(msg);
+} 
+
+static int mce_available(struct cpuinfo_x86 *c)
+{
+	return cpu_has(c, X86_FEATURE_MCE) && cpu_has(c, X86_FEATURE_MCA);
+}
+
+static inline void mce_get_rip(struct mce *m, struct pt_regs *regs)
+{
+	if (regs && (m->mcgstatus & MCG_STATUS_RIPV)) {
+		m->rip = regs->rip;
+		m->cs = regs->cs;
+	} else {
+		m->rip = 0;
+		m->cs = 0;
+	}
+	if (rip_msr) {
+		/* Assume the RIP in the MSR is exact. Is this true? */
+		m->mcgstatus |= MCG_STATUS_EIPV;
+		rdmsrl(rip_msr, m->rip);
+		m->cs = 0;
+	}
+}
+
+/* 
+ * The actual machine check handler
+ */
+
+void do_machine_check(struct pt_regs * regs, long error_code)
+{
+	struct mce m, panicm;
+	u64 mcestart = 0;
+	int i;
+	int panicm_found = 0;
+	/*
+	 * If no_way_out gets set, there is no safe way to recover from this
+	 * MCE.  If tolerant is cranked up, we'll try anyway.
+	 */
+	int no_way_out = 0;
+	/*
+	 * If kill_it gets set, there might be a way to recover from this
+	 * error.
+	 */
+	int kill_it = 0;
+
+	atomic_inc(&mce_entry);
+
+	if (regs)
+		notify_die(DIE_NMI, "machine check", regs, error_code, 18, SIGKILL);
+	if (!banks)
+		goto out2;
+
+	memset(&m, 0, sizeof(struct mce));
+	m.cpu = smp_processor_id();
+	rdmsrl(MSR_IA32_MCG_STATUS, m.mcgstatus);
+	/* if the restart IP is not valid, we're done for */
+	if (!(m.mcgstatus & MCG_STATUS_RIPV))
+		no_way_out = 1;
+	
+	rdtscll(mcestart);
+	barrier();
+
+	for (i = 0; i < banks; i++) {
+		if (!bank[i])
+			continue;
+		
+		m.misc = 0; 
+		m.addr = 0;
+		m.bank = i;
+		m.tsc = 0;
+
+		rdmsrl(MSR_IA32_MC0_STATUS + i*4, m.status);
+		if ((m.status & MCI_STATUS_VAL) == 0)
+			continue;
+
+		if (m.status & MCI_STATUS_EN) {
+			/* if PCC was set, there's no way out */
+			no_way_out |= !!(m.status & MCI_STATUS_PCC);
+			/*
+			 * If this error was uncorrectable and there was
+			 * an overflow, we're in trouble.  If no overflow,
+			 * we might get away with just killing a task.
+			 */
+			if (m.status & MCI_STATUS_UC) {
+				if (tolerant < 1 || m.status & MCI_STATUS_OVER)
+					no_way_out = 1;
+				kill_it = 1;
+			}
+		}
+
+		if (m.status & MCI_STATUS_MISCV)
+			rdmsrl(MSR_IA32_MC0_MISC + i*4, m.misc);
+		if (m.status & MCI_STATUS_ADDRV)
+			rdmsrl(MSR_IA32_MC0_ADDR + i*4, m.addr);
+
+		mce_get_rip(&m, regs);
+		if (error_code >= 0)
+			rdtscll(m.tsc);
+		if (error_code != -2)
+			mce_log(&m);
+
+		/* Did this bank cause the exception? */
+		/* Assume that the bank with uncorrectable errors did it,
+		   and that there is only a single one. */
+		if ((m.status & MCI_STATUS_UC) && (m.status & MCI_STATUS_EN)) {
+			panicm = m;
+			panicm_found = 1;
+		}
+
+		add_taint(TAINT_MACHINE_CHECK);
+	}
+
+	/* Never do anything final in the polling timer */
+	if (!regs)
+		goto out;
+
+	/* If we didn't find an uncorrectable error, pick
+	   the last one (shouldn't happen, just being safe). */
+	if (!panicm_found)
+		panicm = m;
+
+	/*
+	 * If we have decided that we just CAN'T continue, and the user
+	 *  has not set tolerant to an insane level, give up and die.
+	 */
+	if (no_way_out && tolerant < 3)
+		mce_panic("Machine check", &panicm, mcestart);
+
+	/*
+	 * If the error seems to be unrecoverable, something should be
+	 * done.  Try to kill as little as possible.  If we can kill just
+	 * one task, do that.  If the user has set the tolerance very
+	 * high, don't try to do anything at all.
+	 */
+	if (kill_it && tolerant < 3) {
+		int user_space = 0;
+
+		/*
+		 * If the EIPV bit is set, it means the saved IP is the
+		 * instruction which caused the MCE.
+		 */
+		if (m.mcgstatus & MCG_STATUS_EIPV)
+			user_space = panicm.rip && (panicm.cs & 3);
+
+		/*
+		 * If we know that the error was in user space, send a
+		 * SIGBUS.  Otherwise, panic if tolerance is low.
+		 *
+		 * do_exit() takes an awful lot of locks and has a slight
+		 * risk of deadlocking.
+		 */
+		if (user_space) {
+			do_exit(SIGBUS);
+		} else if (panic_on_oops || tolerant < 2) {
+			mce_panic("Uncorrected machine check",
+				&panicm, mcestart);
+		}
+	}
+
+	/* notify userspace ASAP */
+	set_thread_flag(TIF_MCE_NOTIFY);
+
+ out:
+	/* the last thing we do is clear state */
+	for (i = 0; i < banks; i++)
+		wrmsrl(MSR_IA32_MC0_STATUS+4*i, 0);
+	wrmsrl(MSR_IA32_MCG_STATUS, 0);
+ out2:
+	atomic_dec(&mce_entry);
+}
+
+#ifdef CONFIG_X86_MCE_INTEL
+/***
+ * mce_log_therm_throt_event - Logs the thermal throttling event to mcelog
+ * @cpu: The CPU on which the event occured.
+ * @status: Event status information
+ *
+ * This function should be called by the thermal interrupt after the
+ * event has been processed and the decision was made to log the event
+ * further.
+ *
+ * The status parameter will be saved to the 'status' field of 'struct mce'
+ * and historically has been the register value of the
+ * MSR_IA32_THERMAL_STATUS (Intel) msr.
+ */
+void mce_log_therm_throt_event(unsigned int cpu, __u64 status)
+{
+	struct mce m;
+
+	memset(&m, 0, sizeof(m));
+	m.cpu = cpu;
+	m.bank = MCE_THERMAL_BANK;
+	m.status = status;
+	rdtscll(m.tsc);
+	mce_log(&m);
+}
+#endif /* CONFIG_X86_MCE_INTEL */
+
+/*
+ * Periodic polling timer for "silent" machine check errors.  If the
+ * poller finds an MCE, poll 2x faster.  When the poller finds no more
+ * errors, poll 2x slower (up to check_interval seconds).
+ */
+
+static int check_interval = 5 * 60; /* 5 minutes */
+static int next_interval; /* in jiffies */
+static void mcheck_timer(struct work_struct *work);
+static DECLARE_DELAYED_WORK(mcheck_work, mcheck_timer);
+
+static void mcheck_check_cpu(void *info)
+{
+	if (mce_available(&current_cpu_data))
+		do_machine_check(NULL, 0);
+}
+
+static void mcheck_timer(struct work_struct *work)
+{
+	on_each_cpu(mcheck_check_cpu, NULL, 1, 1);
+
+	/*
+	 * Alert userspace if needed.  If we logged an MCE, reduce the
+	 * polling interval, otherwise increase the polling interval.
+	 */
+	if (mce_notify_user()) {
+		next_interval = max(next_interval/2, HZ/100);
+	} else {
+		next_interval = min(next_interval*2,
+				(int)round_jiffies_relative(check_interval*HZ));
+	}
+
+	schedule_delayed_work(&mcheck_work, next_interval);
+}
+
+/*
+ * This is only called from process context.  This is where we do
+ * anything we need to alert userspace about new MCEs.  This is called
+ * directly from the poller and also from entry.S and idle, thanks to
+ * TIF_MCE_NOTIFY.
+ */
+int mce_notify_user(void)
+{
+	clear_thread_flag(TIF_MCE_NOTIFY);
+	if (test_and_clear_bit(0, &notify_user)) {
+		static unsigned long last_print;
+		unsigned long now = jiffies;
+
+		wake_up_interruptible(&mce_wait);
+		if (trigger[0])
+			call_usermodehelper(trigger, trigger_argv, NULL,
+						UMH_NO_WAIT);
+
+		if (time_after_eq(now, last_print + (check_interval*HZ))) {
+			last_print = now;
+			printk(KERN_INFO "Machine check events logged\n");
+		}
+
+		return 1;
+	}
+	return 0;
+}
+
+/* see if the idle task needs to notify userspace */
+static int
+mce_idle_callback(struct notifier_block *nfb, unsigned long action, void *junk)
+{
+	/* IDLE_END should be safe - interrupts are back on */
+	if (action == IDLE_END && test_thread_flag(TIF_MCE_NOTIFY))
+		mce_notify_user();
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block mce_idle_notifier = {
+	.notifier_call = mce_idle_callback,
+};
+
+static __init int periodic_mcheck_init(void)
+{ 
+	next_interval = check_interval * HZ;
+	if (next_interval)
+		schedule_delayed_work(&mcheck_work,
+				      round_jiffies_relative(next_interval));
+	idle_notifier_register(&mce_idle_notifier);
+	return 0;
+} 
+__initcall(periodic_mcheck_init);
+
+
+/* 
+ * Initialize Machine Checks for a CPU.
+ */
+static void mce_init(void *dummy)
+{
+	u64 cap;
+	int i;
+
+	rdmsrl(MSR_IA32_MCG_CAP, cap);
+	banks = cap & 0xff;
+	if (banks > NR_BANKS) { 
+		printk(KERN_INFO "MCE: warning: using only %d banks\n", banks);
+		banks = NR_BANKS; 
+	}
+	/* Use accurate RIP reporting if available. */
+	if ((cap & (1<<9)) && ((cap >> 16) & 0xff) >= 9)
+		rip_msr = MSR_IA32_MCG_EIP;
+
+	/* Log the machine checks left over from the previous reset.
+	   This also clears all registers */
+	do_machine_check(NULL, mce_bootlog ? -1 : -2);
+
+	set_in_cr4(X86_CR4_MCE);
+
+	if (cap & MCG_CTL_P)
+		wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff);
+
+	for (i = 0; i < banks; i++) {
+		wrmsrl(MSR_IA32_MC0_CTL+4*i, bank[i]);
+		wrmsrl(MSR_IA32_MC0_STATUS+4*i, 0);
+	}	
+}
+
+/* Add per CPU specific workarounds here */
+static void __cpuinit mce_cpu_quirks(struct cpuinfo_x86 *c)
+{ 
+	/* This should be disabled by the BIOS, but isn't always */
+	if (c->x86_vendor == X86_VENDOR_AMD && c->x86 == 15) {
+		/* disable GART TBL walk error reporting, which trips off 
+		   incorrectly with the IOMMU & 3ware & Cerberus. */
+		clear_bit(10, &bank[4]);
+		/* Lots of broken BIOS around that don't clear them
+		   by default and leave crap in there. Don't log. */
+		mce_bootlog = 0;
+	}
+
+}			
+
+static void __cpuinit mce_cpu_features(struct cpuinfo_x86 *c)
+{
+	switch (c->x86_vendor) {
+	case X86_VENDOR_INTEL:
+		mce_intel_feature_init(c);
+		break;
+	case X86_VENDOR_AMD:
+		mce_amd_feature_init(c);
+		break;
+	default:
+		break;
+	}
+}
+
+/* 
+ * Called for each booted CPU to set up machine checks.
+ * Must be called with preempt off. 
+ */
+void __cpuinit mcheck_init(struct cpuinfo_x86 *c)
+{
+	static cpumask_t mce_cpus = CPU_MASK_NONE;
+
+	mce_cpu_quirks(c); 
+
+	if (mce_dont_init ||
+	    cpu_test_and_set(smp_processor_id(), mce_cpus) ||
+	    !mce_available(c))
+		return;
+
+	mce_init(NULL);
+	mce_cpu_features(c);
+}
+
+/*
+ * Character device to read and clear the MCE log.
+ */
+
+static DEFINE_SPINLOCK(mce_state_lock);
+static int open_count;	/* #times opened */
+static int open_exclu;	/* already open exclusive? */
+
+static int mce_open(struct inode *inode, struct file *file)
+{
+	spin_lock(&mce_state_lock);
+
+	if (open_exclu || (open_count && (file->f_flags & O_EXCL))) {
+		spin_unlock(&mce_state_lock);
+		return -EBUSY;
+	}
+
+	if (file->f_flags & O_EXCL)
+		open_exclu = 1;
+	open_count++;
+
+	spin_unlock(&mce_state_lock);
+
+	return nonseekable_open(inode, file);
+}
+
+static int mce_release(struct inode *inode, struct file *file)
+{
+	spin_lock(&mce_state_lock);
+
+	open_count--;
+	open_exclu = 0;
+
+	spin_unlock(&mce_state_lock);
+
+	return 0;
+}
+
+static void collect_tscs(void *data) 
+{ 
+	unsigned long *cpu_tsc = (unsigned long *)data;
+	rdtscll(cpu_tsc[smp_processor_id()]);
+} 
+
+static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize, loff_t *off)
+{
+	unsigned long *cpu_tsc;
+	static DECLARE_MUTEX(mce_read_sem);
+	unsigned next;
+	char __user *buf = ubuf;
+	int i, err;
+
+	cpu_tsc = kmalloc(NR_CPUS * sizeof(long), GFP_KERNEL);
+	if (!cpu_tsc)
+		return -ENOMEM;
+
+	down(&mce_read_sem); 
+	next = rcu_dereference(mcelog.next);
+
+	/* Only supports full reads right now */
+	if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) { 
+		up(&mce_read_sem);
+		kfree(cpu_tsc);
+		return -EINVAL;
+	}
+
+	err = 0;
+	for (i = 0; i < next; i++) {		
+		unsigned long start = jiffies;
+		while (!mcelog.entry[i].finished) {
+			if (time_after_eq(jiffies, start + 2)) {
+				memset(mcelog.entry + i,0, sizeof(struct mce));
+				goto timeout;
+			}
+			cpu_relax();
+		}
+		smp_rmb();
+		err |= copy_to_user(buf, mcelog.entry + i, sizeof(struct mce));
+		buf += sizeof(struct mce); 
+ timeout:
+		;
+	} 
+
+	memset(mcelog.entry, 0, next * sizeof(struct mce));
+	mcelog.next = 0;
+
+	synchronize_sched();
+
+	/* Collect entries that were still getting written before the synchronize. */
+
+	on_each_cpu(collect_tscs, cpu_tsc, 1, 1);
+	for (i = next; i < MCE_LOG_LEN; i++) { 
+		if (mcelog.entry[i].finished && 
+		    mcelog.entry[i].tsc < cpu_tsc[mcelog.entry[i].cpu]) {  
+			err |= copy_to_user(buf, mcelog.entry+i, sizeof(struct mce));
+			smp_rmb();
+			buf += sizeof(struct mce);
+			memset(&mcelog.entry[i], 0, sizeof(struct mce));
+		}
+	} 	
+	up(&mce_read_sem);
+	kfree(cpu_tsc);
+	return err ? -EFAULT : buf - ubuf; 
+}
+
+static unsigned int mce_poll(struct file *file, poll_table *wait)
+{
+	poll_wait(file, &mce_wait, wait);
+	if (rcu_dereference(mcelog.next))
+		return POLLIN | POLLRDNORM;
+	return 0;
+}
+
+static int mce_ioctl(struct inode *i, 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 mce), p);
+	case MCE_GET_LOG_LEN:
+		return put_user(MCE_LOG_LEN, p);		
+	case MCE_GETCLEAR_FLAGS: {
+		unsigned flags;
+		do { 
+			flags = mcelog.flags;
+		} while (cmpxchg(&mcelog.flags, flags, 0) != flags); 
+		return put_user(flags, p); 
+	}
+	default:
+		return -ENOTTY; 
+	} 
+}
+
+static const struct file_operations mce_chrdev_ops = {
+	.open = mce_open,
+	.release = mce_release,
+	.read = mce_read,
+	.poll = mce_poll,
+	.ioctl = mce_ioctl,
+};
+
+static struct miscdevice mce_log_device = {
+	MISC_MCELOG_MINOR,
+	"mcelog",
+	&mce_chrdev_ops,
+};
+
+static unsigned long old_cr4 __initdata;
+
+void __init stop_mce(void)
+{
+	old_cr4 = read_cr4();
+	clear_in_cr4(X86_CR4_MCE);
+}
+
+void __init restart_mce(void)
+{
+	if (old_cr4 & X86_CR4_MCE)
+		set_in_cr4(X86_CR4_MCE);
+}
+
+/* 
+ * Old style boot options parsing. Only for compatibility. 
+ */
+
+static int __init mcheck_disable(char *str)
+{
+	mce_dont_init = 1;
+	return 1;
+}
+
+/* mce=off disables machine check. Note you can reenable it later
+   using sysfs.
+   mce=TOLERANCELEVEL (number, see above)
+   mce=bootlog Log MCEs from before booting. Disabled by default on AMD.
+   mce=nobootlog Don't log MCEs from before booting. */
+static int __init mcheck_enable(char *str)
+{
+	if (*str == '=')
+		str++;
+	if (!strcmp(str, "off"))
+		mce_dont_init = 1;
+	else if (!strcmp(str, "bootlog") || !strcmp(str,"nobootlog"))
+		mce_bootlog = str[0] == 'b';
+	else if (isdigit(str[0]))
+		get_option(&str, &tolerant);
+	else
+		printk("mce= argument %s ignored. Please use /sys", str); 
+	return 1;
+}
+
+__setup("nomce", mcheck_disable);
+__setup("mce", mcheck_enable);
+
+/* 
+ * Sysfs support
+ */ 
+
+/* On resume clear all MCE state. Don't want to see leftovers from the BIOS.
+   Only one CPU is active at this time, the others get readded later using
+   CPU hotplug. */
+static int mce_resume(struct sys_device *dev)
+{
+	mce_init(NULL);
+	return 0;
+}
+
+/* Reinit MCEs after user configuration changes */
+static void mce_restart(void) 
+{ 
+	if (next_interval)
+		cancel_delayed_work(&mcheck_work);
+	/* Timer race is harmless here */
+	on_each_cpu(mce_init, NULL, 1, 1);       
+	next_interval = check_interval * HZ;
+	if (next_interval)
+		schedule_delayed_work(&mcheck_work,
+				      round_jiffies_relative(next_interval));
+}
+
+static struct sysdev_class mce_sysclass = {
+	.resume = mce_resume,
+	set_kset_name("machinecheck"),
+};
+
+DEFINE_PER_CPU(struct sys_device, device_mce);
+
+/* Why are there no generic functions for this? */
+#define ACCESSOR(name, var, start) \
+	static ssize_t show_ ## name(struct sys_device *s, char *buf) { 	   	   \
+		return sprintf(buf, "%lx\n", (unsigned long)var);		   \
+	} 									   \
+	static ssize_t set_ ## name(struct sys_device *s,const char *buf,size_t siz) { \
+		char *end; 							   \
+		unsigned long new = simple_strtoul(buf, &end, 0); 		   \
+		if (end == buf) return -EINVAL;					   \
+		var = new;							   \
+		start; 								   \
+		return end-buf;		     					   \
+	}									   \
+	static SYSDEV_ATTR(name, 0644, show_ ## name, set_ ## name);
+
+/* TBD should generate these dynamically based on number of available banks */
+ACCESSOR(bank0ctl,bank[0],mce_restart())
+ACCESSOR(bank1ctl,bank[1],mce_restart())
+ACCESSOR(bank2ctl,bank[2],mce_restart())
+ACCESSOR(bank3ctl,bank[3],mce_restart())
+ACCESSOR(bank4ctl,bank[4],mce_restart())
+ACCESSOR(bank5ctl,bank[5],mce_restart())
+
+static ssize_t show_trigger(struct sys_device *s, char *buf)
+{
+	strcpy(buf, trigger);
+	strcat(buf, "\n");
+	return strlen(trigger) + 1;
+}
+
+static ssize_t set_trigger(struct sys_device *s,const char *buf,size_t siz)
+{
+	char *p;
+	int len;
+	strncpy(trigger, buf, sizeof(trigger));
+	trigger[sizeof(trigger)-1] = 0;
+	len = strlen(trigger);
+	p = strchr(trigger, '\n');
+	if (*p) *p = 0;
+	return len;
+}
+
+static SYSDEV_ATTR(trigger, 0644, show_trigger, set_trigger);
+ACCESSOR(tolerant,tolerant,)
+ACCESSOR(check_interval,check_interval,mce_restart())
+static struct sysdev_attribute *mce_attributes[] = {
+	&attr_bank0ctl, &attr_bank1ctl, &attr_bank2ctl,
+	&attr_bank3ctl, &attr_bank4ctl, &attr_bank5ctl,
+	&attr_tolerant, &attr_check_interval, &attr_trigger,
+	NULL
+};
+
+/* Per cpu sysdev init.  All of the cpus still share the same ctl bank */
+static __cpuinit int mce_create_device(unsigned int cpu)
+{
+	int err;
+	int i;
+	if (!mce_available(&cpu_data[cpu]))
+		return -EIO;
+
+	per_cpu(device_mce,cpu).id = cpu;
+	per_cpu(device_mce,cpu).cls = &mce_sysclass;
+
+	err = sysdev_register(&per_cpu(device_mce,cpu));
+
+	if (!err) {
+		for (i = 0; mce_attributes[i]; i++)
+			sysdev_create_file(&per_cpu(device_mce,cpu),
+				mce_attributes[i]);
+	}
+	return err;
+}
+
+static void mce_remove_device(unsigned int cpu)
+{
+	int i;
+
+	for (i = 0; mce_attributes[i]; i++)
+		sysdev_remove_file(&per_cpu(device_mce,cpu),
+			mce_attributes[i]);
+	sysdev_unregister(&per_cpu(device_mce,cpu));
+	memset(&per_cpu(device_mce, cpu).kobj, 0, sizeof(struct kobject));
+}
+
+/* Get notified when a cpu comes on/off. Be hotplug friendly. */
+static int
+mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
+{
+	unsigned int cpu = (unsigned long)hcpu;
+
+	switch (action) {
+	case CPU_ONLINE:
+	case CPU_ONLINE_FROZEN:
+		mce_create_device(cpu);
+		break;
+	case CPU_DEAD:
+	case CPU_DEAD_FROZEN:
+		mce_remove_device(cpu);
+		break;
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block mce_cpu_notifier = {
+	.notifier_call = mce_cpu_callback,
+};
+
+static __init int mce_init_device(void)
+{
+	int err;
+	int i = 0;
+
+	if (!mce_available(&boot_cpu_data))
+		return -EIO;
+	err = sysdev_class_register(&mce_sysclass);
+
+	for_each_online_cpu(i) {
+		mce_create_device(i);
+	}
+
+	register_hotcpu_notifier(&mce_cpu_notifier);
+	misc_register(&mce_log_device);
+	return err;
+}
+
+device_initcall(mce_init_device);