/*
* Machine check handler.
*
* K8 parts Copyright 2002,2003 Andi Kleen, SuSE Labs.
* Rest from unknown author(s).
* 2004 Andi Kleen. Rewrote most of it.
* Copyright 2008 Intel Corporation
* Author: Andi Kleen
*/
#include <linux/thread_info.h>
#include <linux/capability.h>
#include <linux/miscdevice.h>
#include <linux/ratelimit.h>
#include <linux/kallsyms.h>
#include <linux/rcupdate.h>
#include <linux/kobject.h>
#include <linux/uaccess.h>
#include <linux/kdebug.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/string.h>
#include <linux/sysdev.h>
#include <linux/ctype.h>
#include <linux/sched.h>
#include <linux/sysfs.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/poll.h>
#include <linux/cpu.h>
#include <linux/smp.h>
#include <linux/fs.h>
#include <asm/processor.h>
#include <asm/idle.h>
#include <asm/mce.h>
#include <asm/msr.h>
#include "mce.h"
/* Handle unconfigured int18 (should never happen) */
static void unexpected_machine_check(struct pt_regs *regs, long error_code)
{
printk(KERN_ERR "CPU#%d: Unexpected int18 (Machine Check).\n",
smp_processor_id());
}
/* Call the installed machine check handler for this CPU setup. */
void (*machine_check_vector)(struct pt_regs *, long error_code) =
unexpected_machine_check;
int mce_disabled;
#ifdef CONFIG_X86_NEW_MCE
#define MISC_MCELOG_MINOR 227
atomic_t mce_entry;
DEFINE_PER_CPU(unsigned, mce_exception_count);
/*
* 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 u64 *bank;
static unsigned long notify_user;
static int rip_msr;
static int mce_bootlog = -1;
static char trigger[128];
static char *trigger_argv[2] = { trigger, NULL };
static unsigned long dont_init_banks;
static DECLARE_WAIT_QUEUE_HEAD(mce_wait);
/* MCA banks polled by the period polling timer for corrected events */
DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
[0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL
};
static inline int skip_bank_init(int i)
{
return i < BITS_PER_LONG && test_bit(i, &dont_init_banks);
}
/* Do initial initialization of a struct mce */
void mce_setup(struct mce *m)
{
memset(m, 0, sizeof(struct mce));
m->cpu = smp_processor_id();
rdtscll(m->tsc);
}
DEFINE_PER_CPU(struct mce, injectm);
EXPORT_PER_CPU_SYMBOL_GPL(injectm);
/*
* 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.
*/
static struct mce_log mcelog = {
MCE_LOG_SIGNATURE,
MCE_LOG_LEN,
};
void mce_log(struct mce *mce)
{
unsigned next, entry;
mce->finished = 0;
wmb();
for (;;) {
entry = rcu_dereference(mcelog.next);
for (;;) {
/*
* When the buffer fills up discard new entries.
* Assume that the earlier errors are the more
* interesting ones:
*/
if (entry >= MCE_LOG_LEN) {
set_bit(MCE_OVERFLOW,
(unsigned long *)&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, ¬ify_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->ip) {
printk(KERN_EMERG "RIP%s %02x:<%016Lx> ",
!(m->mcgstatus & MCG_STATUS_EIPV) ? " !INEXACT!" : "",
m->cs, m->ip);
if (m->cs == __KERNEL_CS)
print_symbol("{%s}", m->ip);
printk("\n");
}
printk(KERN_EMERG "TSC %llx ", m->tsc);
if (m->addr)
printk("ADDR %llx ", m->addr);
if (m->misc)
printk("MISC %llx ", 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, u64 start)
{
int i;
bust_spinlocks(1);
console_verbose();
for (i = 0; i < MCE_LOG_LEN; i++) {
u64 tsc = mcelog.entry[i].tsc;
if ((s64)(tsc - start) < 0)
continue;
print_mce(&mcelog.entry[i]);
if (backup && mcelog.entry[i].tsc == backup->tsc)
backup = NULL;
}
if (backup)
print_mce(backup);
panic(msg);
}
/* Support code for software error injection */
static int msr_to_offset(u32 msr)
{
unsigned bank = __get_cpu_var(injectm.bank);
if (msr == rip_msr)
return offsetof(struct mce, ip);
if (msr == MSR_IA32_MC0_STATUS + bank*4)
return offsetof(struct mce, status);
if (msr == MSR_IA32_MC0_ADDR + bank*4)
return offsetof(struct mce, addr);
if (msr == MSR_IA32_MC0_MISC + bank*4)
return offsetof(struct mce, misc);
if (msr == MSR_IA32_MCG_STATUS)
return offsetof(struct mce, mcgstatus);
return -1;
}
/* MSR access wrappers used for error injection */
static u64 mce_rdmsrl(u32 msr)
{
u64 v;
if (__get_cpu_var(injectm).finished) {
int offset = msr_to_offset(msr);
if (offset < 0)
return 0;
return *(u64 *)((char *)&__get_cpu_var(injectm) + offset);
}
rdmsrl(msr, v);
return v;
}
static void mce_wrmsrl(u32 msr, u64 v)
{
if (__get_cpu_var(injectm).finished) {
int offset = msr_to_offset(msr);
if (offset >= 0)
*(u64 *)((char *)&__get_cpu_var(injectm) + offset) = v;
return;
}
wrmsrl(msr, v);
}
int mce_available(struct cpuinfo_x86 *c)
{
if (mce_disabled)
return 0;
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->ip = regs->ip;
m->cs = regs->cs;
} else {
m->ip = 0;
m->cs = 0;
}
if (rip_msr) {
/* Assume the RIP in the MSR is exact. Is this true? */
m->mcgstatus |= MCG_STATUS_EIPV;
m->ip = mce_rdmsrl(rip_msr);
m->cs = 0;
}
}
/*
* Poll for corrected events or events that happened before reset.
* Those are just logged through /dev/mcelog.
*
* This is executed in standard interrupt context.
*/
void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
{
struct mce m;
int i;
mce_setup(&m);
m.mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
for (i = 0; i < banks; i++) {
if (!bank[i] || !test_bit(i, *b))
continue;
m.misc = 0;
m.addr = 0;
m.bank = i;
m.tsc = 0;
barrier();
m.status = mce_rdmsrl(MSR_IA32_MC0_STATUS + i*4);
if (!(m.status & MCI_STATUS_VAL))
continue;
/*
* Uncorrected events are handled by the exception handler
* when it is enabled. But when the exception is disabled log
* everything.
*
* TBD do the same check for MCI_STATUS_EN here?
*/
if ((m.status & MCI_STATUS_UC) && !(flags & MCP_UC))
continue;
if (m.status & MCI_STATUS_MISCV)
m.misc = mce_rdmsrl(MSR_IA32_MC0_MISC + i*4);
if (m.status & MCI_STATUS_ADDRV)
m.addr = mce_rdmsrl(MSR_IA32_MC0_ADDR + i*4);
if (!(flags & MCP_TIMESTAMP))
m.tsc = 0;
/*
* Don't get the IP here because it's unlikely to
* have anything to do with the actual error location.
*/
if (!(flags & MCP_DONTLOG)) {
mce_log(&m);
add_taint(TAINT_MACHINE_CHECK);
}
/*
* Clear state for this bank.
*/
mce_wrmsrl(MSR_IA32_MC0_STATUS+4*i, 0);
}
/*
* Don't clear MCG_STATUS here because it's only defined for
* exceptions.
*/
sync_core();
}
EXPORT_SYMBOL_GPL(machine_check_poll);
/*
* The actual machine check handler. This only handles real
* exceptions when something got corrupted coming in through int 18.
*
* This is executed in NMI context not subject to normal locking rules. This
* implies that most kernel services cannot be safely used. Don't even
* think about putting a printk in there!
*/
void do_machine_check(struct pt_regs *regs, long error_code)
{
struct mce m, panicm;
int panicm_found = 0;
u64 mcestart = 0;
int i;
/*
* 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;
DECLARE_BITMAP(toclear, MAX_NR_BANKS);
atomic_inc(&mce_entry);
__get_cpu_var(mce_exception_count)++;
if (notify_die(DIE_NMI, "machine check", regs, error_code,
18, SIGKILL) == NOTIFY_STOP)
goto out;
if (!banks)
goto out;
mce_setup(&m);
m.mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
/* 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++) {
__clear_bit(i, toclear);
if (!bank[i])
continue;
m.misc = 0;
m.addr = 0;
m.bank = i;
m.status = mce_rdmsrl(MSR_IA32_MC0_STATUS + i*4);
if ((m.status & MCI_STATUS_VAL) == 0)
continue;
/*
* Non uncorrected errors are handled by machine_check_poll
* Leave them alone.
*/
if ((m.status & MCI_STATUS_UC) == 0)
continue;
/*
* Set taint even when machine check was not enabled.
*/
add_taint(TAINT_MACHINE_CHECK);
__set_bit(i, toclear);
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;
}
} else {
/*
* Machine check event was not enabled. Clear, but
* ignore.
*/
continue;
}
if (m.status & MCI_STATUS_MISCV)
m.misc = mce_rdmsrl(MSR_IA32_MC0_MISC + i*4);
if (m.status & MCI_STATUS_ADDRV)
m.addr = mce_rdmsrl(MSR_IA32_MC0_ADDR + i*4);
mce_get_rip(&m, regs);
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;
}
}
/*
* 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.ip && (panicm.cs & 3);
/*
* If we know that the error was in user space, send a
* SIGBUS. Otherwise, panic if tolerance is low.
*
* force_sig() takes an awful lot of locks and has a slight
* risk of deadlocking.
*/
if (user_space) {
force_sig(SIGBUS, current);
} else if (panic_on_oops || tolerant < 2) {
mce_panic("Uncorrected machine check",
&panicm, mcestart);
}
}
/* notify userspace ASAP */
set_thread_flag(TIF_MCE_NOTIFY);
/* the last thing we do is clear state */
for (i = 0; i < banks; i++) {
if (test_bit(i, toclear))
mce_wrmsrl(MSR_IA32_MC0_STATUS+4*i, 0);
}
mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
out:
atomic_dec(&mce_entry);
sync_core();
}
EXPORT_SYMBOL_GPL(do_machine_check);
#ifdef CONFIG_X86_MCE_INTEL
/***
* mce_log_therm_throt_event - Logs the thermal throttling event to mcelog
* @cpu: The CPU on which the event occurred.
* @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(__u64 status)
{
struct mce m;
mce_setup(&m);
m.bank = MCE_THERMAL_BANK;
m.status = status;
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 DEFINE_PER_CPU(int, next_interval); /* in jiffies */
static DEFINE_PER_CPU(struct timer_list, mce_timer);
static void mcheck_timer(unsigned long data)
{
struct timer_list *t = &per_cpu(mce_timer, data);
int *n;
WARN_ON(smp_processor_id() != data);
if (mce_available(¤t_cpu_data)) {
machine_check_poll(MCP_TIMESTAMP,
&__get_cpu_var(mce_poll_banks));
}
/*
* Alert userspace if needed. If we logged an MCE, reduce the
* polling interval, otherwise increase the polling interval.
*/
n = &__get_cpu_var(next_interval);
if (mce_notify_user())
*n = max(*n/2, HZ/100);
else
*n = min(*n*2, (int)round_jiffies_relative(check_interval*HZ));
t->expires = jiffies + *n;
add_timer(t);
}
static void mce_do_trigger(struct work_struct *work)
{
call_usermodehelper(trigger, trigger_argv, NULL, UMH_NO_WAIT);
}
static DECLARE_WORK(mce_trigger_work, mce_do_trigger);
/*
* Notify the user(s) about new machine check events.
* Can be called from interrupt context, but not from machine check/NMI
* context.
*/
int mce_notify_user(void)
{
/* Not more than two messages every minute */
static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
clear_thread_flag(TIF_MCE_NOTIFY);
if (test_and_clear_bit(0, ¬ify_user)) {
wake_up_interruptible(&mce_wait);
/*
* There is no risk of missing notifications because
* work_pending is always cleared before the function is
* executed.
*/
if (trigger[0] && !work_pending(&mce_trigger_work))
schedule_work(&mce_trigger_work);
if (__ratelimit(&ratelimit))
printk(KERN_INFO "Machine check events logged\n");
return 1;
}
return 0;
}
EXPORT_SYMBOL_GPL(mce_notify_user);
/*
* Initialize Machine Checks for a CPU.
*/
static int mce_cap_init(void)
{
unsigned b;
u64 cap;
rdmsrl(MSR_IA32_MCG_CAP, cap);
b = cap & MCG_BANKCNT_MASK;
printk(KERN_INFO "mce: CPU supports %d MCE banks\n", b);
if (b > MAX_NR_BANKS) {
printk(KERN_WARNING
"MCE: Using only %u machine check banks out of %u\n",
MAX_NR_BANKS, b);
b = MAX_NR_BANKS;
}
/* Don't support asymmetric configurations today */
WARN_ON(banks != 0 && b != banks);
banks = b;
if (!bank) {
bank = kmalloc(banks * sizeof(u64), GFP_KERNEL);
if (!bank)
return -ENOMEM;
memset(bank, 0xff, banks * sizeof(u64));
}
/* Use accurate RIP reporting if available. */
if ((cap & MCG_EXT_P) && MCG_EXT_CNT(cap) >= 9)
rip_msr = MSR_IA32_MCG_EIP;
return 0;
}
static void mce_init(void)
{
mce_banks_t all_banks;
u64 cap;
int i;
/*
* Log the machine checks left over from the previous reset.
*/
bitmap_fill(all_banks, MAX_NR_BANKS);
machine_check_poll(MCP_UC|(!mce_bootlog ? MCP_DONTLOG : 0), &all_banks);
set_in_cr4(X86_CR4_MCE);
rdmsrl(MSR_IA32_MCG_CAP, cap);
if (cap & MCG_CTL_P)
wrmsr(MSR_IA32_MCG_CTL, 0xffffffff, 0xffffffff);
for (i = 0; i < banks; i++) {
if (skip_bank_init(i))
continue;
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 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) {
if (c->x86 == 15 && banks > 4) {
/*
* disable GART TBL walk error reporting, which
* trips off incorrectly with the IOMMU & 3ware
* & Cerberus:
*/
clear_bit(10, (unsigned long *)&bank[4]);
}
if (c->x86 <= 17 && mce_bootlog < 0) {
/*
* Lots of broken BIOS around that don't clear them
* by default and leave crap in there. Don't log:
*/
mce_bootlog = 0;
}
/*
* Various K7s with broken bank 0 around. Always disable
* by default.
*/
if (c->x86 == 6)
bank[0] = 0;
}
if (c->x86_vendor == X86_VENDOR_INTEL) {
/*
* SDM documents that on family 6 bank 0 should not be written
* because it aliases to another special BIOS controlled
* register.
* But it's not aliased anymore on model 0x1a+
* Don't ignore bank 0 completely because there could be a
* valid event later, merely don't write CTL0.
*/
if (c->x86 == 6 && c->x86_model < 0x1A)
__set_bit(0, &dont_init_banks);
}
}
static void __cpuinit mce_ancient_init(struct cpuinfo_x86 *c)
{
if (c->x86 != 5)
return;
switch (c->x86_vendor) {
case X86_VENDOR_INTEL:
if (mce_p5_enabled())
intel_p5_mcheck_init(c);
break;
case X86_VENDOR_CENTAUR:
winchip_mcheck_init(c);
break;
}
}
static void 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;
}
}
static void mce_init_timer(void)
{
struct timer_list *t = &__get_cpu_var(mce_timer);
int *n = &__get_cpu_var(next_interval);
*n = check_interval * HZ;
if (!*n)
return;
setup_timer(t, mcheck_timer, smp_processor_id());
t->expires = round_jiffies(jiffies + *n);
add_timer(t);
}
/*
* Called for each booted CPU to set up machine checks.
* Must be called with preempt off:
*/
void __cpuinit mcheck_init(struct cpuinfo_x86 *c)
{
if (mce_disabled)
return;
mce_ancient_init(c);
if (!mce_available(c))
return;
if (mce_cap_init() < 0) {
mce_disabled = 1;
return;
}
mce_cpu_quirks(c);
machine_check_vector = do_machine_check;
mce_init();
mce_cpu_features(c);
mce_init_timer();
}
/*
* 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 DEFINE_MUTEX(mce_read_mutex);
static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
loff_t *off)
{
char __user *buf = ubuf;
unsigned long *cpu_tsc;
unsigned prev, next;
int i, err;
cpu_tsc = kmalloc(nr_cpu_ids * sizeof(long), GFP_KERNEL);
if (!cpu_tsc)
return -ENOMEM;
mutex_lock(&mce_read_mutex);
next = rcu_dereference(mcelog.next);
/* Only supports full reads right now */
if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
mutex_unlock(&mce_read_mutex);
kfree(cpu_tsc);
return -EINVAL;
}
err = 0;
prev = 0;
do {
for (i = prev; 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 + prev, 0,
(next - prev) * sizeof(struct mce));
prev = next;
next = cmpxchg(&mcelog.next, prev, 0);
} while (next != prev);
synchronize_sched();
/*
* Collect entries that were still getting written before the
* synchronize.
*/
on_each_cpu(collect_tscs, cpu_tsc, 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));
}
}
mutex_unlock(&mce_read_mutex);
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 long mce_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 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;
}
}
/* Modified in mce-inject.c, so not static or const */
struct file_operations mce_chrdev_ops = {
.open = mce_open,
.release = mce_release,
.read = mce_read,
.poll = mce_poll,
.unlocked_ioctl = mce_ioctl,
};
EXPORT_SYMBOL_GPL(mce_chrdev_ops);
static struct miscdevice mce_log_device = {
MISC_MCELOG_MINOR,
"mcelog",
&mce_chrdev_ops,
};
/*
* mce=off disables machine check
* 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 == 0)
enable_p5_mce();
if (*str == '=')
str++;
if (!strcmp(str, "off"))
mce_disabled = 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(KERN_INFO "mce argument %s ignored. Please use /sys\n",
str);
return 0;
}
return 1;
}
__setup("mce", mcheck_enable);
/*
* Sysfs support
*/
/*
* Disable machine checks on suspend and shutdown. We can't really handle
* them later.
*/
static int mce_disable(void)
{
int i;
for (i = 0; i < banks; i++) {
if (!skip_bank_init(i))
wrmsrl(MSR_IA32_MC0_CTL + i*4, 0);
}
return 0;
}
static int mce_suspend(struct sys_device *dev, pm_message_t state)
{
return mce_disable();
}
static int mce_shutdown(struct sys_device *dev)
{
return mce_disable();
}
/*
* 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 re-added later using
* CPU hotplug:
*/
static int mce_resume(struct sys_device *dev)
{
mce_init();
mce_cpu_features(¤t_cpu_data);
return 0;
}
static void mce_cpu_restart(void *data)
{
del_timer_sync(&__get_cpu_var(mce_timer));
if (mce_available(¤t_cpu_data))
mce_init();
mce_init_timer();
}
/* Reinit MCEs after user configuration changes */
static void mce_restart(void)
{
on_each_cpu(mce_cpu_restart, NULL, 1);
}
static struct sysdev_class mce_sysclass = {
.suspend = mce_suspend,
.shutdown = mce_shutdown,
.resume = mce_resume,
.name = "machinecheck",
};
DEFINE_PER_CPU(struct sys_device, mce_dev);
__cpuinitdata
void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
static struct sysdev_attribute *bank_attrs;
static ssize_t show_bank(struct sys_device *s, struct sysdev_attribute *attr,
char *buf)
{
u64 b = bank[attr - bank_attrs];
return sprintf(buf, "%llx\n", b);
}
static ssize_t set_bank(struct sys_device *s, struct sysdev_attribute *attr,
const char *buf, size_t size)
{
u64 new;
if (strict_strtoull(buf, 0, &new) < 0)
return -EINVAL;
bank[attr - bank_attrs] = new;
mce_restart();
return size;
}
static ssize_t
show_trigger(struct sys_device *s, struct sysdev_attribute *attr, char *buf)
{
strcpy(buf, trigger);
strcat(buf, "\n");
return strlen(trigger) + 1;
}
static ssize_t set_trigger(struct sys_device *s, struct sysdev_attribute *attr,
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 ssize_t store_int_with_restart(struct sys_device *s,
struct sysdev_attribute *attr,
const char *buf, size_t size)
{
ssize_t ret = sysdev_store_int(s, attr, buf, size);
mce_restart();
return ret;
}
static SYSDEV_ATTR(trigger, 0644, show_trigger, set_trigger);
static SYSDEV_INT_ATTR(tolerant, 0644, tolerant);
static struct sysdev_ext_attribute attr_check_interval = {
_SYSDEV_ATTR(check_interval, 0644, sysdev_show_int,
store_int_with_restart),
&check_interval
};
static struct sysdev_attribute *mce_attrs[] = {
&attr_tolerant.attr, &attr_check_interval.attr, &attr_trigger,
NULL
};
static cpumask_var_t mce_dev_initialized;
/* Per cpu sysdev init. All of the cpus still share the same ctrl bank: */
static __cpuinit int mce_create_device(unsigned int cpu)
{
int err;
int i;
if (!mce_available(&boot_cpu_data))
return -EIO;
memset(&per_cpu(mce_dev, cpu).kobj, 0, sizeof(struct kobject));
per_cpu(mce_dev, cpu).id = cpu;
per_cpu(mce_dev, cpu).cls = &mce_sysclass;
err = sysdev_register(&per_cpu(mce_dev, cpu));
if (err)
return err;
for (i = 0; mce_attrs[i]; i++) {
err = sysdev_create_file(&per_cpu(mce_dev, cpu), mce_attrs[i]);
if (err)
goto error;
}
for (i = 0; i < banks; i++) {
err = sysdev_create_file(&per_cpu(mce_dev, cpu),
&bank_attrs[i]);
if (err)
goto error2;
}
cpumask_set_cpu(cpu, mce_dev_initialized);
return 0;
error2:
while (--i >= 0)
sysdev_remove_file(&per_cpu(mce_dev, cpu), &bank_attrs[i]);
error:
while (--i >= 0)
sysdev_remove_file(&per_cpu(mce_dev, cpu), mce_attrs[i]);
sysdev_unregister(&per_cpu(mce_dev, cpu));
return err;
}
static __cpuinit void mce_remove_device(unsigned int cpu)
{
int i;
if (!cpumask_test_cpu(cpu, mce_dev_initialized))
return;
for (i = 0; mce_attrs[i]; i++)
sysdev_remove_file(&per_cpu(mce_dev, cpu), mce_attrs[i]);
for (i = 0; i < banks; i++)
sysdev_remove_file(&per_cpu(mce_dev, cpu), &bank_attrs[i]);
sysdev_unregister(&per_cpu(mce_dev, cpu));
cpumask_clear_cpu(cpu, mce_dev_initialized);
}
/* Make sure there are no machine checks on offlined CPUs. */
static void mce_disable_cpu(void *h)
{
unsigned long action = *(unsigned long *)h;
int i;
if (!mce_available(¤t_cpu_data))
return;
if (!(action & CPU_TASKS_FROZEN))
cmci_clear();
for (i = 0; i < banks; i++) {
if (!skip_bank_init(i))
wrmsrl(MSR_IA32_MC0_CTL + i*4, 0);
}
}
static void mce_reenable_cpu(void *h)
{
unsigned long action = *(unsigned long *)h;
int i;
if (!mce_available(¤t_cpu_data))
return;
if (!(action & CPU_TASKS_FROZEN))
cmci_reenable();
for (i = 0; i < banks; i++) {
if (!skip_bank_init(i))
wrmsrl(MSR_IA32_MC0_CTL + i*4, bank[i]);
}
}
/* Get notified when a cpu comes on/off. Be hotplug friendly. */
static int __cpuinit
mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
{
unsigned int cpu = (unsigned long)hcpu;
struct timer_list *t = &per_cpu(mce_timer, cpu);
switch (action) {
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
mce_create_device(cpu);
if (threshold_cpu_callback)
threshold_cpu_callback(action, cpu);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
if (threshold_cpu_callback)
threshold_cpu_callback(action, cpu);
mce_remove_device(cpu);
break;
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
del_timer_sync(t);
smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
break;
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
t->expires = round_jiffies(jiffies +
__get_cpu_var(next_interval));
add_timer_on(t, cpu);
smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
break;
case CPU_POST_DEAD:
/* intentionally ignoring frozen here */
cmci_rediscover(cpu);
break;
}
return NOTIFY_OK;
}
static struct notifier_block mce_cpu_notifier __cpuinitdata = {
.notifier_call = mce_cpu_callback,
};
static __init int mce_init_banks(void)
{
int i;
bank_attrs = kzalloc(sizeof(struct sysdev_attribute) * banks,
GFP_KERNEL);
if (!bank_attrs)
return -ENOMEM;
for (i = 0; i < banks; i++) {
struct sysdev_attribute *a = &bank_attrs[i];
a->attr.name = kasprintf(GFP_KERNEL, "bank%d", i);
if (!a->attr.name)
goto nomem;
a->attr.mode = 0644;
a->show = show_bank;
a->store = set_bank;
}
return 0;
nomem:
while (--i >= 0)
kfree(bank_attrs[i].attr.name);
kfree(bank_attrs);
bank_attrs = NULL;
return -ENOMEM;
}
static __init int mce_init_device(void)
{
int err;
int i = 0;
if (!mce_available(&boot_cpu_data))
return -EIO;
alloc_cpumask_var(&mce_dev_initialized, GFP_KERNEL);
err = mce_init_banks();
if (err)
return err;
err = sysdev_class_register(&mce_sysclass);
if (err)
return err;
for_each_online_cpu(i) {
err = mce_create_device(i);
if (err)
return err;
}
register_hotcpu_notifier(&mce_cpu_notifier);
misc_register(&mce_log_device);
return err;
}
device_initcall(mce_init_device);
#else /* CONFIG_X86_OLD_MCE: */
int nr_mce_banks;
EXPORT_SYMBOL_GPL(nr_mce_banks); /* non-fatal.o */
/* This has to be run for each processor */
void mcheck_init(struct cpuinfo_x86 *c)
{
if (mce_disabled == 1)
return;
switch (c->x86_vendor) {
case X86_VENDOR_AMD:
amd_mcheck_init(c);
break;
case X86_VENDOR_INTEL:
if (c->x86 == 5)
intel_p5_mcheck_init(c);
if (c->x86 == 6)
intel_p6_mcheck_init(c);
if (c->x86 == 15)
intel_p4_mcheck_init(c);
break;
case X86_VENDOR_CENTAUR:
if (c->x86 == 5)
winchip_mcheck_init(c);
break;
default:
break;
}
printk(KERN_INFO "mce: CPU supports %d MCE banks\n", nr_mce_banks);
}
static int __init mcheck_enable(char *str)
{
mce_disabled = -1;
return 1;
}
__setup("mce", mcheck_enable);
#endif /* CONFIG_X86_OLD_MCE */
/*
* Old style boot options parsing. Only for compatibility.
*/
static int __init mcheck_disable(char *str)
{
mce_disabled = 1;
return 1;
}
__setup("nomce", mcheck_disable);
