summaryrefslogtreecommitdiff
path: root/arch/x86/kernel/cpu/mcheck/mce.c
diff options
context:
space:
mode:
authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/x86/kernel/cpu/mcheck/mce.c
Initial import
Diffstat (limited to 'arch/x86/kernel/cpu/mcheck/mce.c')
-rw-r--r--arch/x86/kernel/cpu/mcheck/mce.c2566
1 files changed, 2566 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
new file mode 100644
index 000000000..20190bdac
--- /dev/null
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -0,0 +1,2566 @@
+/*
+ * 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
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#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/device.h>
+#include <linux/syscore_ops.h>
+#include <linux/delay.h>
+#include <linux/ctype.h>
+#include <linux/sched.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/kmod.h>
+#include <linux/poll.h>
+#include <linux/nmi.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/debugfs.h>
+#include <linux/irq_work.h>
+#include <linux/export.h>
+
+#include <asm/processor.h>
+#include <asm/traps.h>
+#include <asm/tlbflush.h>
+#include <asm/mce.h>
+#include <asm/msr.h>
+
+#include "mce-internal.h"
+
+static DEFINE_MUTEX(mce_chrdev_read_mutex);
+
+#define rcu_dereference_check_mce(p) \
+ rcu_dereference_index_check((p), \
+ rcu_read_lock_sched_held() || \
+ lockdep_is_held(&mce_chrdev_read_mutex))
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/mce.h>
+
+#define SPINUNIT 100 /* 100ns */
+
+DEFINE_PER_CPU(unsigned, mce_exception_count);
+
+struct mce_bank *mce_banks __read_mostly;
+struct mce_vendor_flags mce_flags __read_mostly;
+
+struct mca_config mca_cfg __read_mostly = {
+ .bootlog = -1,
+ /*
+ * 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 corr. errors
+ * 3: never panic or SIGBUS, log all errors (for testing only)
+ */
+ .tolerant = 1,
+ .monarch_timeout = -1
+};
+
+/* User mode helper program triggered by machine check event */
+static unsigned long mce_need_notify;
+static char mce_helper[128];
+static char *mce_helper_argv[2] = { mce_helper, NULL };
+
+static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);
+
+static DEFINE_PER_CPU(struct mce, mces_seen);
+static int cpu_missing;
+
+/*
+ * MCA banks polled by the period polling timer for corrected events.
+ * With Intel CMCI, this only has MCA banks which do not support CMCI (if any).
+ */
+DEFINE_PER_CPU(mce_banks_t, mce_poll_banks) = {
+ [0 ... BITS_TO_LONGS(MAX_NR_BANKS)-1] = ~0UL
+};
+
+/*
+ * MCA banks controlled through firmware first for corrected errors.
+ * This is a global list of banks for which we won't enable CMCI and we
+ * won't poll. Firmware controls these banks and is responsible for
+ * reporting corrected errors through GHES. Uncorrected/recoverable
+ * errors are still notified through a machine check.
+ */
+mce_banks_t mce_banks_ce_disabled;
+
+static DEFINE_PER_CPU(struct work_struct, mce_work);
+
+static void (*quirk_no_way_out)(int bank, struct mce *m, struct pt_regs *regs);
+
+/*
+ * CPU/chipset specific EDAC code can register a notifier call here to print
+ * MCE errors in a human-readable form.
+ */
+static ATOMIC_NOTIFIER_HEAD(x86_mce_decoder_chain);
+
+/* 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);
+ m->socketid = cpu_data(m->extcpu).phys_proc_id;
+ 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;
+
+ /* Emit the trace record: */
+ trace_mce_record(mce);
+
+ atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
+
+ mce->finished = 0;
+ wmb();
+ for (;;) {
+ entry = rcu_dereference_check_mce(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();
+
+ mce->finished = 1;
+ set_bit(0, &mce_need_notify);
+}
+
+static void drain_mcelog_buffer(void)
+{
+ unsigned int next, i, prev = 0;
+
+ next = ACCESS_ONCE(mcelog.next);
+
+ do {
+ struct mce *m;
+
+ /* drain what was logged during boot */
+ for (i = prev; i < next; i++) {
+ unsigned long start = jiffies;
+ unsigned retries = 1;
+
+ m = &mcelog.entry[i];
+
+ while (!m->finished) {
+ if (time_after_eq(jiffies, start + 2*retries))
+ retries++;
+
+ cpu_relax();
+
+ if (!m->finished && retries >= 4) {
+ pr_err("skipping error being logged currently!\n");
+ break;
+ }
+ }
+ smp_rmb();
+ atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
+ }
+
+ memset(mcelog.entry + prev, 0, (next - prev) * sizeof(*m));
+ prev = next;
+ next = cmpxchg(&mcelog.next, prev, 0);
+ } while (next != prev);
+}
+
+
+void mce_register_decode_chain(struct notifier_block *nb)
+{
+ atomic_notifier_chain_register(&x86_mce_decoder_chain, nb);
+ drain_mcelog_buffer();
+}
+EXPORT_SYMBOL_GPL(mce_register_decode_chain);
+
+void mce_unregister_decode_chain(struct notifier_block *nb)
+{
+ atomic_notifier_chain_unregister(&x86_mce_decoder_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_unregister_decode_chain);
+
+static void print_mce(struct mce *m)
+{
+ int ret = 0;
+
+ pr_emerg(HW_ERR "CPU %d: Machine Check Exception: %Lx Bank %d: %016Lx\n",
+ m->extcpu, m->mcgstatus, m->bank, m->status);
+
+ if (m->ip) {
+ pr_emerg(HW_ERR "RIP%s %02x:<%016Lx> ",
+ !(m->mcgstatus & MCG_STATUS_EIPV) ? " !INEXACT!" : "",
+ m->cs, m->ip);
+
+ if (m->cs == __KERNEL_CS)
+ print_symbol("{%s}", m->ip);
+ pr_cont("\n");
+ }
+
+ pr_emerg(HW_ERR "TSC %llx ", m->tsc);
+ if (m->addr)
+ pr_cont("ADDR %llx ", m->addr);
+ if (m->misc)
+ pr_cont("MISC %llx ", m->misc);
+
+ pr_cont("\n");
+ /*
+ * Note this output is parsed by external tools and old fields
+ * should not be changed.
+ */
+ pr_emerg(HW_ERR "PROCESSOR %u:%x TIME %llu SOCKET %u APIC %x microcode %x\n",
+ m->cpuvendor, m->cpuid, m->time, m->socketid, m->apicid,
+ cpu_data(m->extcpu).microcode);
+
+ /*
+ * Print out human-readable details about the MCE error,
+ * (if the CPU has an implementation for that)
+ */
+ ret = atomic_notifier_call_chain(&x86_mce_decoder_chain, 0, m);
+ if (ret == NOTIFY_STOP)
+ return;
+
+ pr_emerg_ratelimited(HW_ERR "Run the above through 'mcelog --ascii'\n");
+}
+
+#define PANIC_TIMEOUT 5 /* 5 seconds */
+
+static atomic_t mce_panicked;
+
+static int fake_panic;
+static atomic_t mce_fake_panicked;
+
+/* Panic in progress. Enable interrupts and wait for final IPI */
+static void wait_for_panic(void)
+{
+ long timeout = PANIC_TIMEOUT*USEC_PER_SEC;
+
+ preempt_disable();
+ local_irq_enable();
+ while (timeout-- > 0)
+ udelay(1);
+ if (panic_timeout == 0)
+ panic_timeout = mca_cfg.panic_timeout;
+ panic("Panicing machine check CPU died");
+}
+
+static void mce_panic(const char *msg, struct mce *final, char *exp)
+{
+ int i, apei_err = 0;
+
+ if (!fake_panic) {
+ /*
+ * Make sure only one CPU runs in machine check panic
+ */
+ if (atomic_inc_return(&mce_panicked) > 1)
+ wait_for_panic();
+ barrier();
+
+ bust_spinlocks(1);
+ console_verbose();
+ } else {
+ /* Don't log too much for fake panic */
+ if (atomic_inc_return(&mce_fake_panicked) > 1)
+ return;
+ }
+ /* First print corrected ones that are still unlogged */
+ for (i = 0; i < MCE_LOG_LEN; i++) {
+ struct mce *m = &mcelog.entry[i];
+ if (!(m->status & MCI_STATUS_VAL))
+ continue;
+ if (!(m->status & MCI_STATUS_UC)) {
+ print_mce(m);
+ if (!apei_err)
+ apei_err = apei_write_mce(m);
+ }
+ }
+ /* Now print uncorrected but with the final one last */
+ for (i = 0; i < MCE_LOG_LEN; i++) {
+ struct mce *m = &mcelog.entry[i];
+ if (!(m->status & MCI_STATUS_VAL))
+ continue;
+ if (!(m->status & MCI_STATUS_UC))
+ continue;
+ if (!final || memcmp(m, final, sizeof(struct mce))) {
+ print_mce(m);
+ if (!apei_err)
+ apei_err = apei_write_mce(m);
+ }
+ }
+ if (final) {
+ print_mce(final);
+ if (!apei_err)
+ apei_err = apei_write_mce(final);
+ }
+ if (cpu_missing)
+ pr_emerg(HW_ERR "Some CPUs didn't answer in synchronization\n");
+ if (exp)
+ pr_emerg(HW_ERR "Machine check: %s\n", exp);
+ if (!fake_panic) {
+ if (panic_timeout == 0)
+ panic_timeout = mca_cfg.panic_timeout;
+ panic(msg);
+ } else
+ pr_emerg(HW_ERR "Fake kernel panic: %s\n", msg);
+}
+
+/* Support code for software error injection */
+
+static int msr_to_offset(u32 msr)
+{
+ unsigned bank = __this_cpu_read(injectm.bank);
+
+ if (msr == mca_cfg.rip_msr)
+ return offsetof(struct mce, ip);
+ if (msr == MSR_IA32_MCx_STATUS(bank))
+ return offsetof(struct mce, status);
+ if (msr == MSR_IA32_MCx_ADDR(bank))
+ return offsetof(struct mce, addr);
+ if (msr == MSR_IA32_MCx_MISC(bank))
+ 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 (__this_cpu_read(injectm.finished)) {
+ int offset = msr_to_offset(msr);
+
+ if (offset < 0)
+ return 0;
+ return *(u64 *)((char *)this_cpu_ptr(&injectm) + offset);
+ }
+
+ if (rdmsrl_safe(msr, &v)) {
+ WARN_ONCE(1, "mce: Unable to read msr %d!\n", msr);
+ /*
+ * Return zero in case the access faulted. This should
+ * not happen normally but can happen if the CPU does
+ * something weird, or if the code is buggy.
+ */
+ v = 0;
+ }
+
+ return v;
+}
+
+static void mce_wrmsrl(u32 msr, u64 v)
+{
+ if (__this_cpu_read(injectm.finished)) {
+ int offset = msr_to_offset(msr);
+
+ if (offset >= 0)
+ *(u64 *)((char *)this_cpu_ptr(&injectm) + offset) = v;
+ return;
+ }
+ wrmsrl(msr, v);
+}
+
+/*
+ * Collect all global (w.r.t. this processor) status about this machine
+ * check into our "mce" struct so that we can use it later to assess
+ * the severity of the problem as we read per-bank specific details.
+ */
+static inline void mce_gather_info(struct mce *m, struct pt_regs *regs)
+{
+ mce_setup(m);
+
+ m->mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS);
+ if (regs) {
+ /*
+ * Get the address of the instruction at the time of
+ * the machine check error.
+ */
+ if (m->mcgstatus & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) {
+ m->ip = regs->ip;
+ m->cs = regs->cs;
+
+ /*
+ * When in VM86 mode make the cs look like ring 3
+ * always. This is a lie, but it's better than passing
+ * the additional vm86 bit around everywhere.
+ */
+ if (v8086_mode(regs))
+ m->cs |= 3;
+ }
+ /* Use accurate RIP reporting if available. */
+ if (mca_cfg.rip_msr)
+ m->ip = mce_rdmsrl(mca_cfg.rip_msr);
+ }
+}
+
+/*
+ * Simple lockless ring to communicate PFNs from the exception handler with the
+ * process context work function. This is vastly simplified because there's
+ * only a single reader and a single writer.
+ */
+#define MCE_RING_SIZE 16 /* we use one entry less */
+
+struct mce_ring {
+ unsigned short start;
+ unsigned short end;
+ unsigned long ring[MCE_RING_SIZE];
+};
+static DEFINE_PER_CPU(struct mce_ring, mce_ring);
+
+/* Runs with CPU affinity in workqueue */
+static int mce_ring_empty(void)
+{
+ struct mce_ring *r = this_cpu_ptr(&mce_ring);
+
+ return r->start == r->end;
+}
+
+static int mce_ring_get(unsigned long *pfn)
+{
+ struct mce_ring *r;
+ int ret = 0;
+
+ *pfn = 0;
+ get_cpu();
+ r = this_cpu_ptr(&mce_ring);
+ if (r->start == r->end)
+ goto out;
+ *pfn = r->ring[r->start];
+ r->start = (r->start + 1) % MCE_RING_SIZE;
+ ret = 1;
+out:
+ put_cpu();
+ return ret;
+}
+
+/* Always runs in MCE context with preempt off */
+static int mce_ring_add(unsigned long pfn)
+{
+ struct mce_ring *r = this_cpu_ptr(&mce_ring);
+ unsigned next;
+
+ next = (r->end + 1) % MCE_RING_SIZE;
+ if (next == r->start)
+ return -1;
+ r->ring[r->end] = pfn;
+ wmb();
+ r->end = next;
+ return 0;
+}
+
+int mce_available(struct cpuinfo_x86 *c)
+{
+ if (mca_cfg.disabled)
+ return 0;
+ return cpu_has(c, X86_FEATURE_MCE) && cpu_has(c, X86_FEATURE_MCA);
+}
+
+static void mce_schedule_work(void)
+{
+ if (!mce_ring_empty())
+ schedule_work(this_cpu_ptr(&mce_work));
+}
+
+static DEFINE_PER_CPU(struct irq_work, mce_irq_work);
+
+static void mce_irq_work_cb(struct irq_work *entry)
+{
+ mce_notify_irq();
+ mce_schedule_work();
+}
+
+static void mce_report_event(struct pt_regs *regs)
+{
+ if (regs->flags & (X86_VM_MASK|X86_EFLAGS_IF)) {
+ mce_notify_irq();
+ /*
+ * Triggering the work queue here is just an insurance
+ * policy in case the syscall exit notify handler
+ * doesn't run soon enough or ends up running on the
+ * wrong CPU (can happen when audit sleeps)
+ */
+ mce_schedule_work();
+ return;
+ }
+
+ irq_work_queue(this_cpu_ptr(&mce_irq_work));
+}
+
+/*
+ * Read ADDR and MISC registers.
+ */
+static void mce_read_aux(struct mce *m, int i)
+{
+ if (m->status & MCI_STATUS_MISCV)
+ m->misc = mce_rdmsrl(MSR_IA32_MCx_MISC(i));
+ if (m->status & MCI_STATUS_ADDRV) {
+ m->addr = mce_rdmsrl(MSR_IA32_MCx_ADDR(i));
+
+ /*
+ * Mask the reported address by the reported granularity.
+ */
+ if (mca_cfg.ser && (m->status & MCI_STATUS_MISCV)) {
+ u8 shift = MCI_MISC_ADDR_LSB(m->misc);
+ m->addr >>= shift;
+ m->addr <<= shift;
+ }
+ }
+}
+
+static bool memory_error(struct mce *m)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+
+ if (c->x86_vendor == X86_VENDOR_AMD) {
+ /*
+ * coming soon
+ */
+ return false;
+ } else if (c->x86_vendor == X86_VENDOR_INTEL) {
+ /*
+ * Intel SDM Volume 3B - 15.9.2 Compound Error Codes
+ *
+ * Bit 7 of the MCACOD field of IA32_MCi_STATUS is used for
+ * indicating a memory error. Bit 8 is used for indicating a
+ * cache hierarchy error. The combination of bit 2 and bit 3
+ * is used for indicating a `generic' cache hierarchy error
+ * But we can't just blindly check the above bits, because if
+ * bit 11 is set, then it is a bus/interconnect error - and
+ * either way the above bits just gives more detail on what
+ * bus/interconnect error happened. Note that bit 12 can be
+ * ignored, as it's the "filter" bit.
+ */
+ return (m->status & 0xef80) == BIT(7) ||
+ (m->status & 0xef00) == BIT(8) ||
+ (m->status & 0xeffc) == 0xc;
+ }
+
+ return false;
+}
+
+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.
+ *
+ * Note: spec recommends to panic for fatal unsignalled
+ * errors here. However this would be quite problematic --
+ * we would need to reimplement the Monarch handling and
+ * it would mess up the exclusion between exception handler
+ * and poll hander -- * so we skip this for now.
+ * These cases should not happen anyways, or only when the CPU
+ * is already totally * confused. In this case it's likely it will
+ * not fully execute the machine check handler either.
+ */
+bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
+{
+ bool error_logged = false;
+ struct mce m;
+ int severity;
+ int i;
+
+ this_cpu_inc(mce_poll_count);
+
+ mce_gather_info(&m, NULL);
+
+ for (i = 0; i < mca_cfg.banks; i++) {
+ if (!mce_banks[i].ctl || !test_bit(i, *b))
+ continue;
+
+ m.misc = 0;
+ m.addr = 0;
+ m.bank = i;
+ m.tsc = 0;
+
+ barrier();
+ m.status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i));
+ if (!(m.status & MCI_STATUS_VAL))
+ continue;
+
+
+ /*
+ * Uncorrected or signalled events are handled by the exception
+ * handler when it is enabled, so don't process those here.
+ *
+ * TBD do the same check for MCI_STATUS_EN here?
+ */
+ if (!(flags & MCP_UC) &&
+ (m.status & (mca_cfg.ser ? MCI_STATUS_S : MCI_STATUS_UC)))
+ continue;
+
+ mce_read_aux(&m, i);
+
+ if (!(flags & MCP_TIMESTAMP))
+ m.tsc = 0;
+
+ severity = mce_severity(&m, mca_cfg.tolerant, NULL, false);
+
+ /*
+ * In the cases where we don't have a valid address after all,
+ * do not add it into the ring buffer.
+ */
+ if (severity == MCE_DEFERRED_SEVERITY && memory_error(&m)) {
+ if (m.status & MCI_STATUS_ADDRV) {
+ mce_ring_add(m.addr >> PAGE_SHIFT);
+ mce_schedule_work();
+ }
+ }
+
+ /*
+ * Don't get the IP here because it's unlikely to
+ * have anything to do with the actual error location.
+ */
+ if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce) {
+ error_logged = true;
+ mce_log(&m);
+ }
+
+ /*
+ * Clear state for this bank.
+ */
+ mce_wrmsrl(MSR_IA32_MCx_STATUS(i), 0);
+ }
+
+ /*
+ * Don't clear MCG_STATUS here because it's only defined for
+ * exceptions.
+ */
+
+ sync_core();
+
+ return error_logged;
+}
+EXPORT_SYMBOL_GPL(machine_check_poll);
+
+/*
+ * Do a quick check if any of the events requires a panic.
+ * This decides if we keep the events around or clear them.
+ */
+static int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp,
+ struct pt_regs *regs)
+{
+ int i, ret = 0;
+ char *tmp;
+
+ for (i = 0; i < mca_cfg.banks; i++) {
+ m->status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i));
+ if (m->status & MCI_STATUS_VAL) {
+ __set_bit(i, validp);
+ if (quirk_no_way_out)
+ quirk_no_way_out(i, m, regs);
+ }
+
+ if (mce_severity(m, mca_cfg.tolerant, &tmp, true) >= MCE_PANIC_SEVERITY) {
+ *msg = tmp;
+ ret = 1;
+ }
+ }
+ return ret;
+}
+
+/*
+ * Variable to establish order between CPUs while scanning.
+ * Each CPU spins initially until executing is equal its number.
+ */
+static atomic_t mce_executing;
+
+/*
+ * Defines order of CPUs on entry. First CPU becomes Monarch.
+ */
+static atomic_t mce_callin;
+
+/*
+ * Check if a timeout waiting for other CPUs happened.
+ */
+static int mce_timed_out(u64 *t, const char *msg)
+{
+ /*
+ * The others already did panic for some reason.
+ * Bail out like in a timeout.
+ * rmb() to tell the compiler that system_state
+ * might have been modified by someone else.
+ */
+ rmb();
+ if (atomic_read(&mce_panicked))
+ wait_for_panic();
+ if (!mca_cfg.monarch_timeout)
+ goto out;
+ if ((s64)*t < SPINUNIT) {
+ if (mca_cfg.tolerant <= 1)
+ mce_panic(msg, NULL, NULL);
+ cpu_missing = 1;
+ return 1;
+ }
+ *t -= SPINUNIT;
+out:
+ touch_nmi_watchdog();
+ return 0;
+}
+
+/*
+ * The Monarch's reign. The Monarch is the CPU who entered
+ * the machine check handler first. It waits for the others to
+ * raise the exception too and then grades them. When any
+ * error is fatal panic. Only then let the others continue.
+ *
+ * The other CPUs entering the MCE handler will be controlled by the
+ * Monarch. They are called Subjects.
+ *
+ * This way we prevent any potential data corruption in a unrecoverable case
+ * and also makes sure always all CPU's errors are examined.
+ *
+ * Also this detects the case of a machine check event coming from outer
+ * space (not detected by any CPUs) In this case some external agent wants
+ * us to shut down, so panic too.
+ *
+ * The other CPUs might still decide to panic if the handler happens
+ * in a unrecoverable place, but in this case the system is in a semi-stable
+ * state and won't corrupt anything by itself. It's ok to let the others
+ * continue for a bit first.
+ *
+ * All the spin loops have timeouts; when a timeout happens a CPU
+ * typically elects itself to be Monarch.
+ */
+static void mce_reign(void)
+{
+ int cpu;
+ struct mce *m = NULL;
+ int global_worst = 0;
+ char *msg = NULL;
+ char *nmsg = NULL;
+
+ /*
+ * This CPU is the Monarch and the other CPUs have run
+ * through their handlers.
+ * Grade the severity of the errors of all the CPUs.
+ */
+ for_each_possible_cpu(cpu) {
+ int severity = mce_severity(&per_cpu(mces_seen, cpu),
+ mca_cfg.tolerant,
+ &nmsg, true);
+ if (severity > global_worst) {
+ msg = nmsg;
+ global_worst = severity;
+ m = &per_cpu(mces_seen, cpu);
+ }
+ }
+
+ /*
+ * Cannot recover? Panic here then.
+ * This dumps all the mces in the log buffer and stops the
+ * other CPUs.
+ */
+ if (m && global_worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3)
+ mce_panic("Fatal machine check", m, msg);
+
+ /*
+ * For UC somewhere we let the CPU who detects it handle it.
+ * Also must let continue the others, otherwise the handling
+ * CPU could deadlock on a lock.
+ */
+
+ /*
+ * No machine check event found. Must be some external
+ * source or one CPU is hung. Panic.
+ */
+ if (global_worst <= MCE_KEEP_SEVERITY && mca_cfg.tolerant < 3)
+ mce_panic("Fatal machine check from unknown source", NULL, NULL);
+
+ /*
+ * Now clear all the mces_seen so that they don't reappear on
+ * the next mce.
+ */
+ for_each_possible_cpu(cpu)
+ memset(&per_cpu(mces_seen, cpu), 0, sizeof(struct mce));
+}
+
+static atomic_t global_nwo;
+
+/*
+ * Start of Monarch synchronization. This waits until all CPUs have
+ * entered the exception handler and then determines if any of them
+ * saw a fatal event that requires panic. Then it executes them
+ * in the entry order.
+ * TBD double check parallel CPU hotunplug
+ */
+static int mce_start(int *no_way_out)
+{
+ int order;
+ int cpus = num_online_cpus();
+ u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC;
+
+ if (!timeout)
+ return -1;
+
+ atomic_add(*no_way_out, &global_nwo);
+ /*
+ * global_nwo should be updated before mce_callin
+ */
+ smp_wmb();
+ order = atomic_inc_return(&mce_callin);
+
+ /*
+ * Wait for everyone.
+ */
+ while (atomic_read(&mce_callin) != cpus) {
+ if (mce_timed_out(&timeout,
+ "Timeout: Not all CPUs entered broadcast exception handler")) {
+ atomic_set(&global_nwo, 0);
+ return -1;
+ }
+ ndelay(SPINUNIT);
+ }
+
+ /*
+ * mce_callin should be read before global_nwo
+ */
+ smp_rmb();
+
+ if (order == 1) {
+ /*
+ * Monarch: Starts executing now, the others wait.
+ */
+ atomic_set(&mce_executing, 1);
+ } else {
+ /*
+ * Subject: Now start the scanning loop one by one in
+ * the original callin order.
+ * This way when there are any shared banks it will be
+ * only seen by one CPU before cleared, avoiding duplicates.
+ */
+ while (atomic_read(&mce_executing) < order) {
+ if (mce_timed_out(&timeout,
+ "Timeout: Subject CPUs unable to finish machine check processing")) {
+ atomic_set(&global_nwo, 0);
+ return -1;
+ }
+ ndelay(SPINUNIT);
+ }
+ }
+
+ /*
+ * Cache the global no_way_out state.
+ */
+ *no_way_out = atomic_read(&global_nwo);
+
+ return order;
+}
+
+/*
+ * Synchronize between CPUs after main scanning loop.
+ * This invokes the bulk of the Monarch processing.
+ */
+static int mce_end(int order)
+{
+ int ret = -1;
+ u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC;
+
+ if (!timeout)
+ goto reset;
+ if (order < 0)
+ goto reset;
+
+ /*
+ * Allow others to run.
+ */
+ atomic_inc(&mce_executing);
+
+ if (order == 1) {
+ /* CHECKME: Can this race with a parallel hotplug? */
+ int cpus = num_online_cpus();
+
+ /*
+ * Monarch: Wait for everyone to go through their scanning
+ * loops.
+ */
+ while (atomic_read(&mce_executing) <= cpus) {
+ if (mce_timed_out(&timeout,
+ "Timeout: Monarch CPU unable to finish machine check processing"))
+ goto reset;
+ ndelay(SPINUNIT);
+ }
+
+ mce_reign();
+ barrier();
+ ret = 0;
+ } else {
+ /*
+ * Subject: Wait for Monarch to finish.
+ */
+ while (atomic_read(&mce_executing) != 0) {
+ if (mce_timed_out(&timeout,
+ "Timeout: Monarch CPU did not finish machine check processing"))
+ goto reset;
+ ndelay(SPINUNIT);
+ }
+
+ /*
+ * Don't reset anything. That's done by the Monarch.
+ */
+ return 0;
+ }
+
+ /*
+ * Reset all global state.
+ */
+reset:
+ atomic_set(&global_nwo, 0);
+ atomic_set(&mce_callin, 0);
+ barrier();
+
+ /*
+ * Let others run again.
+ */
+ atomic_set(&mce_executing, 0);
+ return ret;
+}
+
+/*
+ * Check if the address reported by the CPU is in a format we can parse.
+ * It would be possible to add code for most other cases, but all would
+ * be somewhat complicated (e.g. segment offset would require an instruction
+ * parser). So only support physical addresses up to page granuality for now.
+ */
+static int mce_usable_address(struct mce *m)
+{
+ if (!(m->status & MCI_STATUS_MISCV) || !(m->status & MCI_STATUS_ADDRV))
+ return 0;
+ if (MCI_MISC_ADDR_LSB(m->misc) > PAGE_SHIFT)
+ return 0;
+ if (MCI_MISC_ADDR_MODE(m->misc) != MCI_MISC_ADDR_PHYS)
+ return 0;
+ return 1;
+}
+
+static void mce_clear_state(unsigned long *toclear)
+{
+ int i;
+
+ for (i = 0; i < mca_cfg.banks; i++) {
+ if (test_bit(i, toclear))
+ mce_wrmsrl(MSR_IA32_MCx_STATUS(i), 0);
+ }
+}
+
+/*
+ * 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!
+ *
+ * On Intel systems this is entered on all CPUs in parallel through
+ * MCE broadcast. However some CPUs might be broken beyond repair,
+ * so be always careful when synchronizing with others.
+ */
+void do_machine_check(struct pt_regs *regs, long error_code)
+{
+ struct mca_config *cfg = &mca_cfg;
+ struct mce m, *final;
+ enum ctx_state prev_state;
+ int i;
+ int worst = 0;
+ int severity;
+ /*
+ * Establish sequential order between the CPUs entering the machine
+ * check handler.
+ */
+ int order;
+ /*
+ * If no_way_out gets set, there is no safe way to recover from this
+ * MCE. If mca_cfg.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);
+ DECLARE_BITMAP(valid_banks, MAX_NR_BANKS);
+ char *msg = "Unknown";
+ u64 recover_paddr = ~0ull;
+ int flags = MF_ACTION_REQUIRED;
+
+ prev_state = ist_enter(regs);
+
+ this_cpu_inc(mce_exception_count);
+
+ if (!cfg->banks)
+ goto out;
+
+ mce_gather_info(&m, regs);
+
+ final = this_cpu_ptr(&mces_seen);
+ *final = m;
+
+ memset(valid_banks, 0, sizeof(valid_banks));
+ no_way_out = mce_no_way_out(&m, &msg, valid_banks, regs);
+
+ barrier();
+
+ /*
+ * When no restart IP might need to kill or panic.
+ * Assume the worst for now, but if we find the
+ * severity is MCE_AR_SEVERITY we have other options.
+ */
+ if (!(m.mcgstatus & MCG_STATUS_RIPV))
+ kill_it = 1;
+
+ /*
+ * Go through all the banks in exclusion of the other CPUs.
+ * This way we don't report duplicated events on shared banks
+ * because the first one to see it will clear it.
+ */
+ order = mce_start(&no_way_out);
+ for (i = 0; i < cfg->banks; i++) {
+ __clear_bit(i, toclear);
+ if (!test_bit(i, valid_banks))
+ continue;
+ if (!mce_banks[i].ctl)
+ continue;
+
+ m.misc = 0;
+ m.addr = 0;
+ m.bank = i;
+
+ m.status = mce_rdmsrl(MSR_IA32_MCx_STATUS(i));
+ if ((m.status & MCI_STATUS_VAL) == 0)
+ continue;
+
+ /*
+ * Non uncorrected or non signaled errors are handled by
+ * machine_check_poll. Leave them alone, unless this panics.
+ */
+ if (!(m.status & (cfg->ser ? MCI_STATUS_S : MCI_STATUS_UC)) &&
+ !no_way_out)
+ continue;
+
+ /*
+ * Set taint even when machine check was not enabled.
+ */
+ add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
+
+ severity = mce_severity(&m, cfg->tolerant, NULL, true);
+
+ /*
+ * When machine check was for corrected/deferred handler don't
+ * touch, unless we're panicing.
+ */
+ if ((severity == MCE_KEEP_SEVERITY ||
+ severity == MCE_UCNA_SEVERITY) && !no_way_out)
+ continue;
+ __set_bit(i, toclear);
+ if (severity == MCE_NO_SEVERITY) {
+ /*
+ * Machine check event was not enabled. Clear, but
+ * ignore.
+ */
+ continue;
+ }
+
+ mce_read_aux(&m, i);
+
+ /*
+ * Action optional error. Queue address for later processing.
+ * When the ring overflows we just ignore the AO error.
+ * RED-PEN add some logging mechanism when
+ * usable_address or mce_add_ring fails.
+ * RED-PEN don't ignore overflow for mca_cfg.tolerant == 0
+ */
+ if (severity == MCE_AO_SEVERITY && mce_usable_address(&m))
+ mce_ring_add(m.addr >> PAGE_SHIFT);
+
+ mce_log(&m);
+
+ if (severity > worst) {
+ *final = m;
+ worst = severity;
+ }
+ }
+
+ /* mce_clear_state will clear *final, save locally for use later */
+ m = *final;
+
+ if (!no_way_out)
+ mce_clear_state(toclear);
+
+ /*
+ * Do most of the synchronization with other CPUs.
+ * When there's any problem use only local no_way_out state.
+ */
+ if (mce_end(order) < 0)
+ no_way_out = worst >= MCE_PANIC_SEVERITY;
+
+ /*
+ * At insane "tolerant" levels we take no action. Otherwise
+ * we only die if we have no other choice. For less serious
+ * issues we try to recover, or limit damage to the current
+ * process.
+ */
+ if (cfg->tolerant < 3) {
+ if (no_way_out)
+ mce_panic("Fatal machine check on current CPU", &m, msg);
+ if (worst == MCE_AR_SEVERITY) {
+ recover_paddr = m.addr;
+ if (!(m.mcgstatus & MCG_STATUS_RIPV))
+ flags |= MF_MUST_KILL;
+ } else if (kill_it) {
+ force_sig(SIGBUS, current);
+ }
+ }
+
+ if (worst > 0)
+ mce_report_event(regs);
+ mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
+out:
+ sync_core();
+
+ if (recover_paddr == ~0ull)
+ goto done;
+
+ pr_err("Uncorrected hardware memory error in user-access at %llx",
+ recover_paddr);
+ /*
+ * We must call memory_failure() here even if the current process is
+ * doomed. We still need to mark the page as poisoned and alert any
+ * other users of the page.
+ */
+ ist_begin_non_atomic(regs);
+ local_irq_enable();
+ if (memory_failure(recover_paddr >> PAGE_SHIFT, MCE_VECTOR, flags) < 0) {
+ pr_err("Memory error not recovered");
+ force_sig(SIGBUS, current);
+ }
+ local_irq_disable();
+ ist_end_non_atomic();
+done:
+ ist_exit(regs, prev_state);
+}
+EXPORT_SYMBOL_GPL(do_machine_check);
+
+#ifndef CONFIG_MEMORY_FAILURE
+int memory_failure(unsigned long pfn, int vector, int flags)
+{
+ /* mce_severity() should not hand us an ACTION_REQUIRED error */
+ BUG_ON(flags & MF_ACTION_REQUIRED);
+ pr_err("Uncorrected memory error in page 0x%lx ignored\n"
+ "Rebuild kernel with CONFIG_MEMORY_FAILURE=y for smarter handling\n",
+ pfn);
+
+ return 0;
+}
+#endif
+
+/*
+ * Action optional processing happens here (picking up
+ * from the list of faulting pages that do_machine_check()
+ * placed into the "ring").
+ */
+static void mce_process_work(struct work_struct *dummy)
+{
+ unsigned long pfn;
+
+ while (mce_ring_get(&pfn))
+ memory_failure(pfn, MCE_VECTOR, 0);
+}
+
+#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 unsigned long check_interval = INITIAL_CHECK_INTERVAL;
+
+static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */
+static DEFINE_PER_CPU(struct timer_list, mce_timer);
+
+static unsigned long mce_adjust_timer_default(unsigned long interval)
+{
+ return interval;
+}
+
+static unsigned long (*mce_adjust_timer)(unsigned long interval) = mce_adjust_timer_default;
+
+static void __restart_timer(struct timer_list *t, unsigned long interval)
+{
+ unsigned long when = jiffies + interval;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ if (timer_pending(t)) {
+ if (time_before(when, t->expires))
+ mod_timer_pinned(t, when);
+ } else {
+ t->expires = round_jiffies(when);
+ add_timer_on(t, smp_processor_id());
+ }
+
+ local_irq_restore(flags);
+}
+
+static void mce_timer_fn(unsigned long data)
+{
+ struct timer_list *t = this_cpu_ptr(&mce_timer);
+ int cpu = smp_processor_id();
+ unsigned long iv;
+
+ WARN_ON(cpu != data);
+
+ iv = __this_cpu_read(mce_next_interval);
+
+ if (mce_available(this_cpu_ptr(&cpu_info))) {
+ machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_poll_banks));
+
+ if (mce_intel_cmci_poll()) {
+ iv = mce_adjust_timer(iv);
+ goto done;
+ }
+ }
+
+ /*
+ * Alert userspace if needed. If we logged an MCE, reduce the polling
+ * interval, otherwise increase the polling interval.
+ */
+ if (mce_notify_irq())
+ iv = max(iv / 2, (unsigned long) HZ/100);
+ else
+ iv = min(iv * 2, round_jiffies_relative(check_interval * HZ));
+
+done:
+ __this_cpu_write(mce_next_interval, iv);
+ __restart_timer(t, iv);
+}
+
+/*
+ * Ensure that the timer is firing in @interval from now.
+ */
+void mce_timer_kick(unsigned long interval)
+{
+ struct timer_list *t = this_cpu_ptr(&mce_timer);
+ unsigned long iv = __this_cpu_read(mce_next_interval);
+
+ __restart_timer(t, interval);
+
+ if (interval < iv)
+ __this_cpu_write(mce_next_interval, interval);
+}
+
+/* Must not be called in IRQ context where del_timer_sync() can deadlock */
+static void mce_timer_delete_all(void)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ del_timer_sync(&per_cpu(mce_timer, cpu));
+}
+
+static void mce_do_trigger(struct work_struct *work)
+{
+ call_usermodehelper(mce_helper, mce_helper_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_irq(void)
+{
+ /* Not more than two messages every minute */
+ static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
+
+ if (test_and_clear_bit(0, &mce_need_notify)) {
+ /* wake processes polling /dev/mcelog */
+ wake_up_interruptible(&mce_chrdev_wait);
+
+ if (mce_helper[0])
+ schedule_work(&mce_trigger_work);
+
+ if (__ratelimit(&ratelimit))
+ pr_info(HW_ERR "Machine check events logged\n");
+
+ return 1;
+ }
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mce_notify_irq);
+
+static int __mcheck_cpu_mce_banks_init(void)
+{
+ int i;
+ u8 num_banks = mca_cfg.banks;
+
+ mce_banks = kzalloc(num_banks * sizeof(struct mce_bank), GFP_KERNEL);
+ if (!mce_banks)
+ return -ENOMEM;
+
+ for (i = 0; i < num_banks; i++) {
+ struct mce_bank *b = &mce_banks[i];
+
+ b->ctl = -1ULL;
+ b->init = 1;
+ }
+ return 0;
+}
+
+/*
+ * Initialize Machine Checks for a CPU.
+ */
+static int __mcheck_cpu_cap_init(void)
+{
+ unsigned b;
+ u64 cap;
+
+ rdmsrl(MSR_IA32_MCG_CAP, cap);
+
+ b = cap & MCG_BANKCNT_MASK;
+ if (!mca_cfg.banks)
+ pr_info("CPU supports %d MCE banks\n", b);
+
+ if (b > MAX_NR_BANKS) {
+ pr_warn("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(mca_cfg.banks != 0 && b != mca_cfg.banks);
+ mca_cfg.banks = b;
+
+ if (!mce_banks) {
+ int err = __mcheck_cpu_mce_banks_init();
+
+ if (err)
+ return err;
+ }
+
+ /* Use accurate RIP reporting if available. */
+ if ((cap & MCG_EXT_P) && MCG_EXT_CNT(cap) >= 9)
+ mca_cfg.rip_msr = MSR_IA32_MCG_EIP;
+
+ if (cap & MCG_SER_P)
+ mca_cfg.ser = true;
+
+ return 0;
+}
+
+static void __mcheck_cpu_init_generic(void)
+{
+ enum mcp_flags m_fl = 0;
+ mce_banks_t all_banks;
+ u64 cap;
+ int i;
+
+ if (!mca_cfg.bootlog)
+ m_fl = MCP_DONTLOG;
+
+ /*
+ * Log the machine checks left over from the previous reset.
+ */
+ bitmap_fill(all_banks, MAX_NR_BANKS);
+ machine_check_poll(MCP_UC | m_fl, &all_banks);
+
+ cr4_set_bits(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 < mca_cfg.banks; i++) {
+ struct mce_bank *b = &mce_banks[i];
+
+ if (!b->init)
+ continue;
+ wrmsrl(MSR_IA32_MCx_CTL(i), b->ctl);
+ wrmsrl(MSR_IA32_MCx_STATUS(i), 0);
+ }
+}
+
+/*
+ * During IFU recovery Sandy Bridge -EP4S processors set the RIPV and
+ * EIPV bits in MCG_STATUS to zero on the affected logical processor (SDM
+ * Vol 3B Table 15-20). But this confuses both the code that determines
+ * whether the machine check occurred in kernel or user mode, and also
+ * the severity assessment code. Pretend that EIPV was set, and take the
+ * ip/cs values from the pt_regs that mce_gather_info() ignored earlier.
+ */
+static void quirk_sandybridge_ifu(int bank, struct mce *m, struct pt_regs *regs)
+{
+ if (bank != 0)
+ return;
+ if ((m->mcgstatus & (MCG_STATUS_EIPV|MCG_STATUS_RIPV)) != 0)
+ return;
+ if ((m->status & (MCI_STATUS_OVER|MCI_STATUS_UC|
+ MCI_STATUS_EN|MCI_STATUS_MISCV|MCI_STATUS_ADDRV|
+ MCI_STATUS_PCC|MCI_STATUS_S|MCI_STATUS_AR|
+ MCACOD)) !=
+ (MCI_STATUS_UC|MCI_STATUS_EN|
+ MCI_STATUS_MISCV|MCI_STATUS_ADDRV|MCI_STATUS_S|
+ MCI_STATUS_AR|MCACOD_INSTR))
+ return;
+
+ m->mcgstatus |= MCG_STATUS_EIPV;
+ m->ip = regs->ip;
+ m->cs = regs->cs;
+}
+
+/* Add per CPU specific workarounds here */
+static int __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c)
+{
+ struct mca_config *cfg = &mca_cfg;
+
+ if (c->x86_vendor == X86_VENDOR_UNKNOWN) {
+ pr_info("unknown CPU type - not enabling MCE support\n");
+ return -EOPNOTSUPP;
+ }
+
+ /* This should be disabled by the BIOS, but isn't always */
+ if (c->x86_vendor == X86_VENDOR_AMD) {
+ if (c->x86 == 15 && cfg->banks > 4) {
+ /*
+ * disable GART TBL walk error reporting, which
+ * trips off incorrectly with the IOMMU & 3ware
+ * & Cerberus:
+ */
+ clear_bit(10, (unsigned long *)&mce_banks[4].ctl);
+ }
+ if (c->x86 <= 17 && cfg->bootlog < 0) {
+ /*
+ * Lots of broken BIOS around that don't clear them
+ * by default and leave crap in there. Don't log:
+ */
+ cfg->bootlog = 0;
+ }
+ /*
+ * Various K7s with broken bank 0 around. Always disable
+ * by default.
+ */
+ if (c->x86 == 6 && cfg->banks > 0)
+ mce_banks[0].ctl = 0;
+
+ /*
+ * overflow_recov is supported for F15h Models 00h-0fh
+ * even though we don't have a CPUID bit for it.
+ */
+ if (c->x86 == 0x15 && c->x86_model <= 0xf)
+ mce_flags.overflow_recov = 1;
+
+ /*
+ * Turn off MC4_MISC thresholding banks on those models since
+ * they're not supported there.
+ */
+ if (c->x86 == 0x15 &&
+ (c->x86_model >= 0x10 && c->x86_model <= 0x1f)) {
+ int i;
+ u64 hwcr;
+ bool need_toggle;
+ u32 msrs[] = {
+ 0x00000413, /* MC4_MISC0 */
+ 0xc0000408, /* MC4_MISC1 */
+ };
+
+ rdmsrl(MSR_K7_HWCR, hwcr);
+
+ /* McStatusWrEn has to be set */
+ need_toggle = !(hwcr & BIT(18));
+
+ if (need_toggle)
+ wrmsrl(MSR_K7_HWCR, hwcr | BIT(18));
+
+ /* Clear CntP bit safely */
+ for (i = 0; i < ARRAY_SIZE(msrs); i++)
+ msr_clear_bit(msrs[i], 62);
+
+ /* restore old settings */
+ if (need_toggle)
+ wrmsrl(MSR_K7_HWCR, hwcr);
+ }
+ }
+
+ 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 && cfg->banks > 0)
+ mce_banks[0].init = 0;
+
+ /*
+ * All newer Intel systems support MCE broadcasting. Enable
+ * synchronization with a one second timeout.
+ */
+ if ((c->x86 > 6 || (c->x86 == 6 && c->x86_model >= 0xe)) &&
+ cfg->monarch_timeout < 0)
+ cfg->monarch_timeout = USEC_PER_SEC;
+
+ /*
+ * There are also broken BIOSes on some Pentium M and
+ * earlier systems:
+ */
+ if (c->x86 == 6 && c->x86_model <= 13 && cfg->bootlog < 0)
+ cfg->bootlog = 0;
+
+ if (c->x86 == 6 && c->x86_model == 45)
+ quirk_no_way_out = quirk_sandybridge_ifu;
+ }
+ if (cfg->monarch_timeout < 0)
+ cfg->monarch_timeout = 0;
+ if (cfg->bootlog != 0)
+ cfg->panic_timeout = 30;
+
+ return 0;
+}
+
+static int __mcheck_cpu_ancient_init(struct cpuinfo_x86 *c)
+{
+ if (c->x86 != 5)
+ return 0;
+
+ switch (c->x86_vendor) {
+ case X86_VENDOR_INTEL:
+ intel_p5_mcheck_init(c);
+ return 1;
+ break;
+ case X86_VENDOR_CENTAUR:
+ winchip_mcheck_init(c);
+ return 1;
+ break;
+ }
+
+ return 0;
+}
+
+static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
+{
+ switch (c->x86_vendor) {
+ case X86_VENDOR_INTEL:
+ mce_intel_feature_init(c);
+ mce_adjust_timer = cmci_intel_adjust_timer;
+ break;
+ case X86_VENDOR_AMD:
+ mce_amd_feature_init(c);
+ mce_flags.overflow_recov = cpuid_ebx(0x80000007) & 0x1;
+ break;
+ default:
+ break;
+ }
+}
+
+static void mce_start_timer(unsigned int cpu, struct timer_list *t)
+{
+ unsigned long iv = check_interval * HZ;
+
+ if (mca_cfg.ignore_ce || !iv)
+ return;
+
+ per_cpu(mce_next_interval, cpu) = iv;
+
+ t->expires = round_jiffies(jiffies + iv);
+ add_timer_on(t, cpu);
+}
+
+static void __mcheck_cpu_init_timer(void)
+{
+ struct timer_list *t = this_cpu_ptr(&mce_timer);
+ unsigned int cpu = smp_processor_id();
+
+ setup_timer(t, mce_timer_fn, cpu);
+ mce_start_timer(cpu, t);
+}
+
+/* Handle unconfigured int18 (should never happen) */
+static void unexpected_machine_check(struct pt_regs *regs, long error_code)
+{
+ pr_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;
+
+/*
+ * Called for each booted CPU to set up machine checks.
+ * Must be called with preempt off:
+ */
+void mcheck_cpu_init(struct cpuinfo_x86 *c)
+{
+ if (mca_cfg.disabled)
+ return;
+
+ if (__mcheck_cpu_ancient_init(c))
+ return;
+
+ if (!mce_available(c))
+ return;
+
+ if (__mcheck_cpu_cap_init() < 0 || __mcheck_cpu_apply_quirks(c) < 0) {
+ mca_cfg.disabled = true;
+ return;
+ }
+
+ machine_check_vector = do_machine_check;
+
+ __mcheck_cpu_init_generic();
+ __mcheck_cpu_init_vendor(c);
+ __mcheck_cpu_init_timer();
+ INIT_WORK(this_cpu_ptr(&mce_work), mce_process_work);
+ init_irq_work(this_cpu_ptr(&mce_irq_work), &mce_irq_work_cb);
+}
+
+/*
+ * mce_chrdev: Character device /dev/mcelog to read and clear the MCE log.
+ */
+
+static DEFINE_SPINLOCK(mce_chrdev_state_lock);
+static int mce_chrdev_open_count; /* #times opened */
+static int mce_chrdev_open_exclu; /* already open exclusive? */
+
+static int mce_chrdev_open(struct inode *inode, struct file *file)
+{
+ spin_lock(&mce_chrdev_state_lock);
+
+ if (mce_chrdev_open_exclu ||
+ (mce_chrdev_open_count && (file->f_flags & O_EXCL))) {
+ spin_unlock(&mce_chrdev_state_lock);
+
+ return -EBUSY;
+ }
+
+ if (file->f_flags & O_EXCL)
+ mce_chrdev_open_exclu = 1;
+ mce_chrdev_open_count++;
+
+ spin_unlock(&mce_chrdev_state_lock);
+
+ return nonseekable_open(inode, file);
+}
+
+static int mce_chrdev_release(struct inode *inode, struct file *file)
+{
+ spin_lock(&mce_chrdev_state_lock);
+
+ mce_chrdev_open_count--;
+ mce_chrdev_open_exclu = 0;
+
+ spin_unlock(&mce_chrdev_state_lock);
+
+ return 0;
+}
+
+static void collect_tscs(void *data)
+{
+ unsigned long *cpu_tsc = (unsigned long *)data;
+
+ rdtscll(cpu_tsc[smp_processor_id()]);
+}
+
+static int mce_apei_read_done;
+
+/* Collect MCE record of previous boot in persistent storage via APEI ERST. */
+static int __mce_read_apei(char __user **ubuf, size_t usize)
+{
+ int rc;
+ u64 record_id;
+ struct mce m;
+
+ if (usize < sizeof(struct mce))
+ return -EINVAL;
+
+ rc = apei_read_mce(&m, &record_id);
+ /* Error or no more MCE record */
+ if (rc <= 0) {
+ mce_apei_read_done = 1;
+ /*
+ * When ERST is disabled, mce_chrdev_read() should return
+ * "no record" instead of "no device."
+ */
+ if (rc == -ENODEV)
+ return 0;
+ return rc;
+ }
+ rc = -EFAULT;
+ if (copy_to_user(*ubuf, &m, sizeof(struct mce)))
+ return rc;
+ /*
+ * In fact, we should have cleared the record after that has
+ * been flushed to the disk or sent to network in
+ * /sbin/mcelog, but we have no interface to support that now,
+ * so just clear it to avoid duplication.
+ */
+ rc = apei_clear_mce(record_id);
+ if (rc) {
+ mce_apei_read_done = 1;
+ return rc;
+ }
+ *ubuf += sizeof(struct mce);
+
+ return 0;
+}
+
+static ssize_t mce_chrdev_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_chrdev_read_mutex);
+
+ if (!mce_apei_read_done) {
+ err = __mce_read_apei(&buf, usize);
+ if (err || buf != ubuf)
+ goto out;
+ }
+
+ next = rcu_dereference_check_mce(mcelog.next);
+
+ /* Only supports full reads right now */
+ err = -EINVAL;
+ if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce))
+ goto out;
+
+ err = 0;
+ prev = 0;
+ do {
+ for (i = prev; i < next; i++) {
+ unsigned long start = jiffies;
+ struct mce *m = &mcelog.entry[i];
+
+ while (!m->finished) {
+ if (time_after_eq(jiffies, start + 2)) {
+ memset(m, 0, sizeof(*m));
+ goto timeout;
+ }
+ cpu_relax();
+ }
+ smp_rmb();
+ err |= copy_to_user(buf, m, sizeof(*m));
+ buf += sizeof(*m);
+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++) {
+ struct mce *m = &mcelog.entry[i];
+
+ if (m->finished && m->tsc < cpu_tsc[m->cpu]) {
+ err |= copy_to_user(buf, m, sizeof(*m));
+ smp_rmb();
+ buf += sizeof(*m);
+ memset(m, 0, sizeof(*m));
+ }
+ }
+
+ if (err)
+ err = -EFAULT;
+
+out:
+ mutex_unlock(&mce_chrdev_read_mutex);
+ kfree(cpu_tsc);
+
+ return err ? err : buf - ubuf;
+}
+
+static unsigned int mce_chrdev_poll(struct file *file, poll_table *wait)
+{
+ poll_wait(file, &mce_chrdev_wait, wait);
+ if (rcu_access_index(mcelog.next))
+ return POLLIN | POLLRDNORM;
+ if (!mce_apei_read_done && apei_check_mce())
+ return POLLIN | POLLRDNORM;
+ return 0;
+}
+
+static long 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 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 ssize_t (*mce_write)(struct file *filp, const char __user *ubuf,
+ size_t usize, loff_t *off);
+
+void register_mce_write_callback(ssize_t (*fn)(struct file *filp,
+ const char __user *ubuf,
+ size_t usize, loff_t *off))
+{
+ mce_write = fn;
+}
+EXPORT_SYMBOL_GPL(register_mce_write_callback);
+
+ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf,
+ size_t usize, loff_t *off)
+{
+ if (mce_write)
+ return mce_write(filp, ubuf, usize, off);
+ else
+ return -EINVAL;
+}
+
+static const struct file_operations mce_chrdev_ops = {
+ .open = mce_chrdev_open,
+ .release = mce_chrdev_release,
+ .read = mce_chrdev_read,
+ .write = mce_chrdev_write,
+ .poll = mce_chrdev_poll,
+ .unlocked_ioctl = mce_chrdev_ioctl,
+ .llseek = no_llseek,
+};
+
+static struct miscdevice mce_chrdev_device = {
+ MISC_MCELOG_MINOR,
+ "mcelog",
+ &mce_chrdev_ops,
+};
+
+static void __mce_disable_bank(void *arg)
+{
+ int bank = *((int *)arg);
+ __clear_bit(bank, this_cpu_ptr(mce_poll_banks));
+ cmci_disable_bank(bank);
+}
+
+void mce_disable_bank(int bank)
+{
+ if (bank >= mca_cfg.banks) {
+ pr_warn(FW_BUG
+ "Ignoring request to disable invalid MCA bank %d.\n",
+ bank);
+ return;
+ }
+ set_bit(bank, mce_banks_ce_disabled);
+ on_each_cpu(__mce_disable_bank, &bank, 1);
+}
+
+/*
+ * mce=off Disables machine check
+ * mce=no_cmci Disables CMCI
+ * mce=dont_log_ce Clears corrected events silently, no log created for CEs.
+ * mce=ignore_ce Disables polling and CMCI, corrected events are not cleared.
+ * mce=TOLERANCELEVEL[,monarchtimeout] (number, see above)
+ * monarchtimeout is how long to wait for other CPUs on machine
+ * check, or 0 to not wait
+ * mce=bootlog Log MCEs from before booting. Disabled by default on AMD.
+ * mce=nobootlog Don't log MCEs from before booting.
+ * mce=bios_cmci_threshold Don't program the CMCI threshold
+ */
+static int __init mcheck_enable(char *str)
+{
+ struct mca_config *cfg = &mca_cfg;
+
+ if (*str == 0) {
+ enable_p5_mce();
+ return 1;
+ }
+ if (*str == '=')
+ str++;
+ if (!strcmp(str, "off"))
+ cfg->disabled = true;
+ else if (!strcmp(str, "no_cmci"))
+ cfg->cmci_disabled = true;
+ else if (!strcmp(str, "dont_log_ce"))
+ cfg->dont_log_ce = true;
+ else if (!strcmp(str, "ignore_ce"))
+ cfg->ignore_ce = true;
+ else if (!strcmp(str, "bootlog") || !strcmp(str, "nobootlog"))
+ cfg->bootlog = (str[0] == 'b');
+ else if (!strcmp(str, "bios_cmci_threshold"))
+ cfg->bios_cmci_threshold = true;
+ else if (isdigit(str[0])) {
+ get_option(&str, &(cfg->tolerant));
+ if (*str == ',') {
+ ++str;
+ get_option(&str, &(cfg->monarch_timeout));
+ }
+ } else {
+ pr_info("mce argument %s ignored. Please use /sys\n", str);
+ return 0;
+ }
+ return 1;
+}
+__setup("mce", mcheck_enable);
+
+int __init mcheck_init(void)
+{
+ mcheck_intel_therm_init();
+ mcheck_vendor_init_severity();
+
+ return 0;
+}
+
+/*
+ * mce_syscore: PM support
+ */
+
+/*
+ * Disable machine checks on suspend and shutdown. We can't really handle
+ * them later.
+ */
+static int mce_disable_error_reporting(void)
+{
+ int i;
+
+ for (i = 0; i < mca_cfg.banks; i++) {
+ struct mce_bank *b = &mce_banks[i];
+
+ if (b->init)
+ wrmsrl(MSR_IA32_MCx_CTL(i), 0);
+ }
+ return 0;
+}
+
+static int mce_syscore_suspend(void)
+{
+ return mce_disable_error_reporting();
+}
+
+static void mce_syscore_shutdown(void)
+{
+ mce_disable_error_reporting();
+}
+
+/*
+ * 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 void mce_syscore_resume(void)
+{
+ __mcheck_cpu_init_generic();
+ __mcheck_cpu_init_vendor(raw_cpu_ptr(&cpu_info));
+}
+
+static struct syscore_ops mce_syscore_ops = {
+ .suspend = mce_syscore_suspend,
+ .shutdown = mce_syscore_shutdown,
+ .resume = mce_syscore_resume,
+};
+
+/*
+ * mce_device: Sysfs support
+ */
+
+static void mce_cpu_restart(void *data)
+{
+ if (!mce_available(raw_cpu_ptr(&cpu_info)))
+ return;
+ __mcheck_cpu_init_generic();
+ __mcheck_cpu_init_timer();
+}
+
+/* Reinit MCEs after user configuration changes */
+static void mce_restart(void)
+{
+ mce_timer_delete_all();
+ on_each_cpu(mce_cpu_restart, NULL, 1);
+}
+
+/* Toggle features for corrected errors */
+static void mce_disable_cmci(void *data)
+{
+ if (!mce_available(raw_cpu_ptr(&cpu_info)))
+ return;
+ cmci_clear();
+}
+
+static void mce_enable_ce(void *all)
+{
+ if (!mce_available(raw_cpu_ptr(&cpu_info)))
+ return;
+ cmci_reenable();
+ cmci_recheck();
+ if (all)
+ __mcheck_cpu_init_timer();
+}
+
+static struct bus_type mce_subsys = {
+ .name = "machinecheck",
+ .dev_name = "machinecheck",
+};
+
+DEFINE_PER_CPU(struct device *, mce_device);
+
+void (*threshold_cpu_callback)(unsigned long action, unsigned int cpu);
+
+static inline struct mce_bank *attr_to_bank(struct device_attribute *attr)
+{
+ return container_of(attr, struct mce_bank, attr);
+}
+
+static ssize_t show_bank(struct device *s, struct device_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%llx\n", attr_to_bank(attr)->ctl);
+}
+
+static ssize_t set_bank(struct device *s, struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ u64 new;
+
+ if (kstrtou64(buf, 0, &new) < 0)
+ return -EINVAL;
+
+ attr_to_bank(attr)->ctl = new;
+ mce_restart();
+
+ return size;
+}
+
+static ssize_t
+show_trigger(struct device *s, struct device_attribute *attr, char *buf)
+{
+ strcpy(buf, mce_helper);
+ strcat(buf, "\n");
+ return strlen(mce_helper) + 1;
+}
+
+static ssize_t set_trigger(struct device *s, struct device_attribute *attr,
+ const char *buf, size_t siz)
+{
+ char *p;
+
+ strncpy(mce_helper, buf, sizeof(mce_helper));
+ mce_helper[sizeof(mce_helper)-1] = 0;
+ p = strchr(mce_helper, '\n');
+
+ if (p)
+ *p = 0;
+
+ return strlen(mce_helper) + !!p;
+}
+
+static ssize_t set_ignore_ce(struct device *s,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ u64 new;
+
+ if (kstrtou64(buf, 0, &new) < 0)
+ return -EINVAL;
+
+ if (mca_cfg.ignore_ce ^ !!new) {
+ if (new) {
+ /* disable ce features */
+ mce_timer_delete_all();
+ on_each_cpu(mce_disable_cmci, NULL, 1);
+ mca_cfg.ignore_ce = true;
+ } else {
+ /* enable ce features */
+ mca_cfg.ignore_ce = false;
+ on_each_cpu(mce_enable_ce, (void *)1, 1);
+ }
+ }
+ return size;
+}
+
+static ssize_t set_cmci_disabled(struct device *s,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ u64 new;
+
+ if (kstrtou64(buf, 0, &new) < 0)
+ return -EINVAL;
+
+ if (mca_cfg.cmci_disabled ^ !!new) {
+ if (new) {
+ /* disable cmci */
+ on_each_cpu(mce_disable_cmci, NULL, 1);
+ mca_cfg.cmci_disabled = true;
+ } else {
+ /* enable cmci */
+ mca_cfg.cmci_disabled = false;
+ on_each_cpu(mce_enable_ce, NULL, 1);
+ }
+ }
+ return size;
+}
+
+static ssize_t store_int_with_restart(struct device *s,
+ struct device_attribute *attr,
+ const char *buf, size_t size)
+{
+ ssize_t ret = device_store_int(s, attr, buf, size);
+ mce_restart();
+ return ret;
+}
+
+static DEVICE_ATTR(trigger, 0644, show_trigger, set_trigger);
+static DEVICE_INT_ATTR(tolerant, 0644, mca_cfg.tolerant);
+static DEVICE_INT_ATTR(monarch_timeout, 0644, mca_cfg.monarch_timeout);
+static DEVICE_BOOL_ATTR(dont_log_ce, 0644, mca_cfg.dont_log_ce);
+
+static struct dev_ext_attribute dev_attr_check_interval = {
+ __ATTR(check_interval, 0644, device_show_int, store_int_with_restart),
+ &check_interval
+};
+
+static struct dev_ext_attribute dev_attr_ignore_ce = {
+ __ATTR(ignore_ce, 0644, device_show_bool, set_ignore_ce),
+ &mca_cfg.ignore_ce
+};
+
+static struct dev_ext_attribute dev_attr_cmci_disabled = {
+ __ATTR(cmci_disabled, 0644, device_show_bool, set_cmci_disabled),
+ &mca_cfg.cmci_disabled
+};
+
+static struct device_attribute *mce_device_attrs[] = {
+ &dev_attr_tolerant.attr,
+ &dev_attr_check_interval.attr,
+ &dev_attr_trigger,
+ &dev_attr_monarch_timeout.attr,
+ &dev_attr_dont_log_ce.attr,
+ &dev_attr_ignore_ce.attr,
+ &dev_attr_cmci_disabled.attr,
+ NULL
+};
+
+static cpumask_var_t mce_device_initialized;
+
+static void mce_device_release(struct device *dev)
+{
+ kfree(dev);
+}
+
+/* Per cpu device init. All of the cpus still share the same ctrl bank: */
+static int mce_device_create(unsigned int cpu)
+{
+ struct device *dev;
+ int err;
+ int i, j;
+
+ if (!mce_available(&boot_cpu_data))
+ return -EIO;
+
+ dev = kzalloc(sizeof *dev, GFP_KERNEL);
+ if (!dev)
+ return -ENOMEM;
+ dev->id = cpu;
+ dev->bus = &mce_subsys;
+ dev->release = &mce_device_release;
+
+ err = device_register(dev);
+ if (err) {
+ put_device(dev);
+ return err;
+ }
+
+ for (i = 0; mce_device_attrs[i]; i++) {
+ err = device_create_file(dev, mce_device_attrs[i]);
+ if (err)
+ goto error;
+ }
+ for (j = 0; j < mca_cfg.banks; j++) {
+ err = device_create_file(dev, &mce_banks[j].attr);
+ if (err)
+ goto error2;
+ }
+ cpumask_set_cpu(cpu, mce_device_initialized);
+ per_cpu(mce_device, cpu) = dev;
+
+ return 0;
+error2:
+ while (--j >= 0)
+ device_remove_file(dev, &mce_banks[j].attr);
+error:
+ while (--i >= 0)
+ device_remove_file(dev, mce_device_attrs[i]);
+
+ device_unregister(dev);
+
+ return err;
+}
+
+static void mce_device_remove(unsigned int cpu)
+{
+ struct device *dev = per_cpu(mce_device, cpu);
+ int i;
+
+ if (!cpumask_test_cpu(cpu, mce_device_initialized))
+ return;
+
+ for (i = 0; mce_device_attrs[i]; i++)
+ device_remove_file(dev, mce_device_attrs[i]);
+
+ for (i = 0; i < mca_cfg.banks; i++)
+ device_remove_file(dev, &mce_banks[i].attr);
+
+ device_unregister(dev);
+ cpumask_clear_cpu(cpu, mce_device_initialized);
+ per_cpu(mce_device, cpu) = NULL;
+}
+
+/* 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(raw_cpu_ptr(&cpu_info)))
+ return;
+
+ if (!(action & CPU_TASKS_FROZEN))
+ cmci_clear();
+ for (i = 0; i < mca_cfg.banks; i++) {
+ struct mce_bank *b = &mce_banks[i];
+
+ if (b->init)
+ wrmsrl(MSR_IA32_MCx_CTL(i), 0);
+ }
+}
+
+static void mce_reenable_cpu(void *h)
+{
+ unsigned long action = *(unsigned long *)h;
+ int i;
+
+ if (!mce_available(raw_cpu_ptr(&cpu_info)))
+ return;
+
+ if (!(action & CPU_TASKS_FROZEN))
+ cmci_reenable();
+ for (i = 0; i < mca_cfg.banks; i++) {
+ struct mce_bank *b = &mce_banks[i];
+
+ if (b->init)
+ wrmsrl(MSR_IA32_MCx_CTL(i), b->ctl);
+ }
+}
+
+/* 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;
+ struct timer_list *t = &per_cpu(mce_timer, cpu);
+
+ switch (action & ~CPU_TASKS_FROZEN) {
+ case CPU_ONLINE:
+ mce_device_create(cpu);
+ if (threshold_cpu_callback)
+ threshold_cpu_callback(action, cpu);
+ break;
+ case CPU_DEAD:
+ if (threshold_cpu_callback)
+ threshold_cpu_callback(action, cpu);
+ mce_device_remove(cpu);
+ mce_intel_hcpu_update(cpu);
+
+ /* intentionally ignoring frozen here */
+ if (!(action & CPU_TASKS_FROZEN))
+ cmci_rediscover();
+ break;
+ case CPU_DOWN_PREPARE:
+ smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
+ del_timer_sync(t);
+ break;
+ case CPU_DOWN_FAILED:
+ smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
+ mce_start_timer(cpu, t);
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block mce_cpu_notifier = {
+ .notifier_call = mce_cpu_callback,
+};
+
+static __init void mce_init_banks(void)
+{
+ int i;
+
+ for (i = 0; i < mca_cfg.banks; i++) {
+ struct mce_bank *b = &mce_banks[i];
+ struct device_attribute *a = &b->attr;
+
+ sysfs_attr_init(&a->attr);
+ a->attr.name = b->attrname;
+ snprintf(b->attrname, ATTR_LEN, "bank%d", i);
+
+ a->attr.mode = 0644;
+ a->show = show_bank;
+ a->store = set_bank;
+ }
+}
+
+static __init int mcheck_init_device(void)
+{
+ int err;
+ int i = 0;
+
+ if (!mce_available(&boot_cpu_data)) {
+ err = -EIO;
+ goto err_out;
+ }
+
+ if (!zalloc_cpumask_var(&mce_device_initialized, GFP_KERNEL)) {
+ err = -ENOMEM;
+ goto err_out;
+ }
+
+ mce_init_banks();
+
+ err = subsys_system_register(&mce_subsys, NULL);
+ if (err)
+ goto err_out_mem;
+
+ cpu_notifier_register_begin();
+ for_each_online_cpu(i) {
+ err = mce_device_create(i);
+ if (err) {
+ /*
+ * Register notifier anyway (and do not unreg it) so
+ * that we don't leave undeleted timers, see notifier
+ * callback above.
+ */
+ __register_hotcpu_notifier(&mce_cpu_notifier);
+ cpu_notifier_register_done();
+ goto err_device_create;
+ }
+ }
+
+ __register_hotcpu_notifier(&mce_cpu_notifier);
+ cpu_notifier_register_done();
+
+ register_syscore_ops(&mce_syscore_ops);
+
+ /* register character device /dev/mcelog */
+ err = misc_register(&mce_chrdev_device);
+ if (err)
+ goto err_register;
+
+ return 0;
+
+err_register:
+ unregister_syscore_ops(&mce_syscore_ops);
+
+err_device_create:
+ /*
+ * We didn't keep track of which devices were created above, but
+ * even if we had, the set of online cpus might have changed.
+ * Play safe and remove for every possible cpu, since
+ * mce_device_remove() will do the right thing.
+ */
+ for_each_possible_cpu(i)
+ mce_device_remove(i);
+
+err_out_mem:
+ free_cpumask_var(mce_device_initialized);
+
+err_out:
+ pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
+
+ return err;
+}
+device_initcall_sync(mcheck_init_device);
+
+/*
+ * Old style boot options parsing. Only for compatibility.
+ */
+static int __init mcheck_disable(char *str)
+{
+ mca_cfg.disabled = true;
+ return 1;
+}
+__setup("nomce", mcheck_disable);
+
+#ifdef CONFIG_DEBUG_FS
+struct dentry *mce_get_debugfs_dir(void)
+{
+ static struct dentry *dmce;
+
+ if (!dmce)
+ dmce = debugfs_create_dir("mce", NULL);
+
+ return dmce;
+}
+
+static void mce_reset(void)
+{
+ cpu_missing = 0;
+ atomic_set(&mce_fake_panicked, 0);
+ atomic_set(&mce_executing, 0);
+ atomic_set(&mce_callin, 0);
+ atomic_set(&global_nwo, 0);
+}
+
+static int fake_panic_get(void *data, u64 *val)
+{
+ *val = fake_panic;
+ return 0;
+}
+
+static int fake_panic_set(void *data, u64 val)
+{
+ mce_reset();
+ fake_panic = val;
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fake_panic_fops, fake_panic_get,
+ fake_panic_set, "%llu\n");
+
+static int __init mcheck_debugfs_init(void)
+{
+ struct dentry *dmce, *ffake_panic;
+
+ dmce = mce_get_debugfs_dir();
+ if (!dmce)
+ return -ENOMEM;
+ ffake_panic = debugfs_create_file("fake_panic", 0444, dmce, NULL,
+ &fake_panic_fops);
+ if (!ffake_panic)
+ return -ENOMEM;
+
+ return 0;
+}
+late_initcall(mcheck_debugfs_init);
+#endif