/* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #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 = m->extcpu = smp_processor_id(); rdtscll(m->tsc); /* We hope get_seconds stays lockless */ m->time = get_seconds(); m->cpuvendor = boot_cpu_data.x86_vendor; m->cpuid = cpuid_eax(1); #ifdef CONFIG_SMP m->socketid = cpu_data(m->extcpu).phys_proc_id; #endif m->apicid = cpu_data(m->extcpu).initial_apicid; rdmsrl(MSR_IA32_MCG_CAP, m->mcgcap); } 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 = { .signature = MCE_LOG_SIGNATURE, .len = MCE_LOG_LEN, .recordlen = sizeof(struct mce), }; 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->extcpu, 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 "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x\n", m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid); 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; } } DEFINE_PER_CPU(unsigned, mce_poll_count); /* * 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; __get_cpu_var(mce_poll_count)++; 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);