diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mce/core.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mce/core.c | 2871 |
1 files changed, 2871 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c new file mode 100644 index 000000000..6f35f724c --- /dev/null +++ b/arch/x86/kernel/cpu/mce/core.c @@ -0,0 +1,2871 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * 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/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/ras.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 <linux/set_memory.h> +#include <linux/sync_core.h> +#include <linux/task_work.h> +#include <linux/hardirq.h> + +#include <asm/intel-family.h> +#include <asm/processor.h> +#include <asm/traps.h> +#include <asm/tlbflush.h> +#include <asm/mce.h> +#include <asm/msr.h> +#include <asm/reboot.h> + +#include "internal.h" + +/* sysfs synchronization */ +static DEFINE_MUTEX(mce_sysfs_mutex); + +#define CREATE_TRACE_POINTS +#include <trace/events/mce.h> + +#define SPINUNIT 100 /* 100ns */ + +DEFINE_PER_CPU(unsigned, mce_exception_count); + +DEFINE_PER_CPU_READ_MOSTLY(unsigned int, mce_num_banks); + +DEFINE_PER_CPU_READ_MOSTLY(struct mce_bank[MAX_NR_BANKS], mce_banks_array); + +#define ATTR_LEN 16 +/* One object for each MCE bank, shared by all CPUs */ +struct mce_bank_dev { + struct device_attribute attr; /* device attribute */ + char attrname[ATTR_LEN]; /* attribute name */ + u8 bank; /* bank number */ +}; +static struct mce_bank_dev mce_bank_devs[MAX_NR_BANKS]; + +struct mce_vendor_flags mce_flags __read_mostly; + +struct mca_config mca_cfg __read_mostly = { + .bootlog = -1, + .monarch_timeout = -1 +}; + +static DEFINE_PER_CPU(struct mce, mces_seen); +static unsigned long mce_need_notify; + +/* + * 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 struct work_struct mce_work; +static struct irq_work mce_irq_work; + +/* + * CPU/chipset specific EDAC code can register a notifier call here to print + * MCE errors in a human-readable form. + */ +BLOCKING_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(); + /* need the internal __ version to avoid deadlocks */ + m->time = __ktime_get_real_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; + m->mcgcap = __rdmsr(MSR_IA32_MCG_CAP); + m->ppin = cpu_data(m->extcpu).ppin; + m->microcode = boot_cpu_data.microcode; +} + +DEFINE_PER_CPU(struct mce, injectm); +EXPORT_PER_CPU_SYMBOL_GPL(injectm); + +void mce_log(struct mce *m) +{ + if (!mce_gen_pool_add(m)) + irq_work_queue(&mce_irq_work); +} +EXPORT_SYMBOL_GPL(mce_log); + +void mce_register_decode_chain(struct notifier_block *nb) +{ + if (WARN_ON(nb->priority < MCE_PRIO_LOWEST || + nb->priority > MCE_PRIO_HIGHEST)) + return; + + blocking_notifier_chain_register(&x86_mce_decoder_chain, nb); +} +EXPORT_SYMBOL_GPL(mce_register_decode_chain); + +void mce_unregister_decode_chain(struct notifier_block *nb) +{ + blocking_notifier_chain_unregister(&x86_mce_decoder_chain, nb); +} +EXPORT_SYMBOL_GPL(mce_unregister_decode_chain); + +static void __print_mce(struct mce *m) +{ + pr_emerg(HW_ERR "CPU %d: Machine Check%s: %Lx Bank %d: %016Lx\n", + m->extcpu, + (m->mcgstatus & MCG_STATUS_MCIP ? " Exception" : ""), + 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) + pr_cont("{%pS}", (void *)(unsigned long)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); + if (m->ppin) + pr_cont("PPIN %llx ", m->ppin); + + if (mce_flags.smca) { + if (m->synd) + pr_cont("SYND %llx ", m->synd); + if (m->ipid) + pr_cont("IPID %llx ", m->ipid); + } + + 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, + m->microcode); +} + +static void print_mce(struct mce *m) +{ + __print_mce(m); + + if (m->cpuvendor != X86_VENDOR_AMD && m->cpuvendor != X86_VENDOR_HYGON) + 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 noinstr void mce_panic(const char *msg, struct mce *final, char *exp) +{ + struct llist_node *pending; + struct mce_evt_llist *l; + int apei_err = 0; + + /* + * Allow instrumentation around external facilities usage. Not that it + * matters a whole lot since the machine is going to panic anyway. + */ + instrumentation_begin(); + + 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) + goto out; + } + pending = mce_gen_pool_prepare_records(); + /* First print corrected ones that are still unlogged */ + llist_for_each_entry(l, pending, llnode) { + struct mce *m = &l->mce; + 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 */ + llist_for_each_entry(l, pending, llnode) { + struct mce *m = &l->mce; + if (!(m->status & MCI_STATUS_UC)) + continue; + if (!final || mce_cmp(m, final)) { + 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 (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); + +out: + instrumentation_end(); +} + +/* 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 == mca_msr_reg(bank, MCA_STATUS)) + return offsetof(struct mce, status); + if (msr == mca_msr_reg(bank, MCA_ADDR)) + return offsetof(struct mce, addr); + if (msr == mca_msr_reg(bank, MCA_MISC)) + return offsetof(struct mce, misc); + if (msr == MSR_IA32_MCG_STATUS) + return offsetof(struct mce, mcgstatus); + return -1; +} + +void ex_handler_msr_mce(struct pt_regs *regs, bool wrmsr) +{ + if (wrmsr) { + pr_emerg("MSR access error: WRMSR to 0x%x (tried to write 0x%08x%08x) at rIP: 0x%lx (%pS)\n", + (unsigned int)regs->cx, (unsigned int)regs->dx, (unsigned int)regs->ax, + regs->ip, (void *)regs->ip); + } else { + pr_emerg("MSR access error: RDMSR from 0x%x at rIP: 0x%lx (%pS)\n", + (unsigned int)regs->cx, regs->ip, (void *)regs->ip); + } + + show_stack_regs(regs); + + panic("MCA architectural violation!\n"); + + while (true) + cpu_relax(); +} + +/* MSR access wrappers used for error injection */ +noinstr u64 mce_rdmsrl(u32 msr) +{ + DECLARE_ARGS(val, low, high); + + if (__this_cpu_read(injectm.finished)) { + int offset; + u64 ret; + + instrumentation_begin(); + + offset = msr_to_offset(msr); + if (offset < 0) + ret = 0; + else + ret = *(u64 *)((char *)this_cpu_ptr(&injectm) + offset); + + instrumentation_end(); + + return ret; + } + + /* + * RDMSR on MCA MSRs should not fault. If they do, this is very much an + * architectural violation and needs to be reported to hw vendor. Panic + * the box to not allow any further progress. + */ + asm volatile("1: rdmsr\n" + "2:\n" + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_RDMSR_IN_MCE) + : EAX_EDX_RET(val, low, high) : "c" (msr)); + + + return EAX_EDX_VAL(val, low, high); +} + +static noinstr void mce_wrmsrl(u32 msr, u64 v) +{ + u32 low, high; + + if (__this_cpu_read(injectm.finished)) { + int offset; + + instrumentation_begin(); + + offset = msr_to_offset(msr); + if (offset >= 0) + *(u64 *)((char *)this_cpu_ptr(&injectm) + offset) = v; + + instrumentation_end(); + + return; + } + + low = (u32)v; + high = (u32)(v >> 32); + + /* See comment in mce_rdmsrl() */ + asm volatile("1: wrmsr\n" + "2:\n" + _ASM_EXTABLE_TYPE(1b, 2b, EX_TYPE_WRMSR_IN_MCE) + : : "c" (msr), "a"(low), "d" (high) : "memory"); +} + +/* + * 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 noinstr void mce_gather_info(struct mce *m, struct pt_regs *regs) +{ + /* + * Enable instrumentation around mce_setup() which calls external + * facilities. + */ + instrumentation_begin(); + mce_setup(m); + instrumentation_end(); + + 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); + } +} + +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_gen_pool_empty()) + schedule_work(&mce_work); +} + +static void mce_irq_work_cb(struct irq_work *entry) +{ + mce_schedule_work(); +} + +/* + * 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 granularity for now. + */ +int mce_usable_address(struct mce *m) +{ + if (!(m->status & MCI_STATUS_ADDRV)) + return 0; + + /* Checks after this one are Intel/Zhaoxin-specific: */ + if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL && + boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN) + return 1; + + if (!(m->status & MCI_STATUS_MISCV)) + 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; +} +EXPORT_SYMBOL_GPL(mce_usable_address); + +bool mce_is_memory_error(struct mce *m) +{ + switch (m->cpuvendor) { + case X86_VENDOR_AMD: + case X86_VENDOR_HYGON: + return amd_mce_is_memory_error(m); + + case X86_VENDOR_INTEL: + case X86_VENDOR_ZHAOXIN: + /* + * 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; + + default: + return false; + } +} +EXPORT_SYMBOL_GPL(mce_is_memory_error); + +static bool whole_page(struct mce *m) +{ + if (!mca_cfg.ser || !(m->status & MCI_STATUS_MISCV)) + return true; + + return MCI_MISC_ADDR_LSB(m->misc) >= PAGE_SHIFT; +} + +bool mce_is_correctable(struct mce *m) +{ + if (m->cpuvendor == X86_VENDOR_AMD && m->status & MCI_STATUS_DEFERRED) + return false; + + if (m->cpuvendor == X86_VENDOR_HYGON && m->status & MCI_STATUS_DEFERRED) + return false; + + if (m->status & MCI_STATUS_UC) + return false; + + return true; +} +EXPORT_SYMBOL_GPL(mce_is_correctable); + +static int mce_early_notifier(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct mce *m = (struct mce *)data; + + if (!m) + return NOTIFY_DONE; + + /* Emit the trace record: */ + trace_mce_record(m); + + set_bit(0, &mce_need_notify); + + mce_notify_irq(); + + return NOTIFY_DONE; +} + +static struct notifier_block early_nb = { + .notifier_call = mce_early_notifier, + .priority = MCE_PRIO_EARLY, +}; + +static int uc_decode_notifier(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct mce *mce = (struct mce *)data; + unsigned long pfn; + + if (!mce || !mce_usable_address(mce)) + return NOTIFY_DONE; + + if (mce->severity != MCE_AO_SEVERITY && + mce->severity != MCE_DEFERRED_SEVERITY) + return NOTIFY_DONE; + + pfn = (mce->addr & MCI_ADDR_PHYSADDR) >> PAGE_SHIFT; + if (!memory_failure(pfn, 0)) { + set_mce_nospec(pfn); + mce->kflags |= MCE_HANDLED_UC; + } + + return NOTIFY_OK; +} + +static struct notifier_block mce_uc_nb = { + .notifier_call = uc_decode_notifier, + .priority = MCE_PRIO_UC, +}; + +static int mce_default_notifier(struct notifier_block *nb, unsigned long val, + void *data) +{ + struct mce *m = (struct mce *)data; + + if (!m) + return NOTIFY_DONE; + + if (mca_cfg.print_all || !m->kflags) + __print_mce(m); + + return NOTIFY_DONE; +} + +static struct notifier_block mce_default_nb = { + .notifier_call = mce_default_notifier, + /* lowest prio, we want it to run last. */ + .priority = MCE_PRIO_LOWEST, +}; + +/* + * Read ADDR and MISC registers. + */ +static noinstr void mce_read_aux(struct mce *m, int i) +{ + if (m->status & MCI_STATUS_MISCV) + m->misc = mce_rdmsrl(mca_msr_reg(i, MCA_MISC)); + + if (m->status & MCI_STATUS_ADDRV) { + m->addr = mce_rdmsrl(mca_msr_reg(i, MCA_ADDR)); + + /* + * 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; + } + + smca_extract_err_addr(m); + } + + if (mce_flags.smca) { + m->ipid = mce_rdmsrl(MSR_AMD64_SMCA_MCx_IPID(i)); + + if (m->status & MCI_STATUS_SYNDV) + m->synd = mce_rdmsrl(MSR_AMD64_SMCA_MCx_SYND(i)); + } +} + +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 handler -- * 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) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + bool error_seen = false; + struct mce m; + int i; + + this_cpu_inc(mce_poll_count); + + mce_gather_info(&m, NULL); + + if (flags & MCP_TIMESTAMP) + m.tsc = rdtsc(); + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + if (!mce_banks[i].ctl || !test_bit(i, *b)) + continue; + + m.misc = 0; + m.addr = 0; + m.bank = i; + + barrier(); + m.status = mce_rdmsrl(mca_msr_reg(i, MCA_STATUS)); + + /* If this entry is not valid, ignore it */ + if (!(m.status & MCI_STATUS_VAL)) + continue; + + /* + * If we are logging everything (at CPU online) or this + * is a corrected error, then we must log it. + */ + if ((flags & MCP_UC) || !(m.status & MCI_STATUS_UC)) + goto log_it; + + /* + * Newer Intel systems that support software error + * recovery need to make additional checks. Other + * CPUs should skip over uncorrected errors, but log + * everything else. + */ + if (!mca_cfg.ser) { + if (m.status & MCI_STATUS_UC) + continue; + goto log_it; + } + + /* Log "not enabled" (speculative) errors */ + if (!(m.status & MCI_STATUS_EN)) + goto log_it; + + /* + * Log UCNA (SDM: 15.6.3 "UCR Error Classification") + * UC == 1 && PCC == 0 && S == 0 + */ + if (!(m.status & MCI_STATUS_PCC) && !(m.status & MCI_STATUS_S)) + goto log_it; + + /* + * Skip anything else. Presumption is that our read of this + * bank is racing with a machine check. Leave the log alone + * for do_machine_check() to deal with it. + */ + continue; + +log_it: + error_seen = true; + + if (flags & MCP_DONTLOG) + goto clear_it; + + mce_read_aux(&m, i); + m.severity = mce_severity(&m, NULL, NULL, false); + /* + * Don't get the IP here because it's unlikely to + * have anything to do with the actual error location. + */ + + if (mca_cfg.dont_log_ce && !mce_usable_address(&m)) + goto clear_it; + + if (flags & MCP_QUEUE_LOG) + mce_gen_pool_add(&m); + else + mce_log(&m); + +clear_it: + /* + * Clear state for this bank. + */ + mce_wrmsrl(mca_msr_reg(i, MCA_STATUS), 0); + } + + /* + * Don't clear MCG_STATUS here because it's only defined for + * exceptions. + */ + + sync_core(); + + return error_seen; +} +EXPORT_SYMBOL_GPL(machine_check_poll); + +/* + * 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 __always_inline 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; +} + +/* + * Disable fast string copy and return from the MCE handler upon the first SRAR + * MCE on bank 1 due to a CPU erratum on Intel Skylake/Cascade Lake/Cooper Lake + * CPUs. + * The fast string copy instructions ("REP; MOVS*") could consume an + * uncorrectable memory error in the cache line _right after_ the desired region + * to copy and raise an MCE with RIP pointing to the instruction _after_ the + * "REP; MOVS*". + * This mitigation addresses the issue completely with the caveat of performance + * degradation on the CPU affected. This is still better than the OS crashing on + * MCEs raised on an irrelevant process due to "REP; MOVS*" accesses from a + * kernel context (e.g., copy_page). + * + * Returns true when fast string copy on CPU has been disabled. + */ +static noinstr bool quirk_skylake_repmov(void) +{ + u64 mcgstatus = mce_rdmsrl(MSR_IA32_MCG_STATUS); + u64 misc_enable = mce_rdmsrl(MSR_IA32_MISC_ENABLE); + u64 mc1_status; + + /* + * Apply the quirk only to local machine checks, i.e., no broadcast + * sync is needed. + */ + if (!(mcgstatus & MCG_STATUS_LMCES) || + !(misc_enable & MSR_IA32_MISC_ENABLE_FAST_STRING)) + return false; + + mc1_status = mce_rdmsrl(MSR_IA32_MCx_STATUS(1)); + + /* Check for a software-recoverable data fetch error. */ + if ((mc1_status & + (MCI_STATUS_VAL | MCI_STATUS_OVER | MCI_STATUS_UC | MCI_STATUS_EN | + MCI_STATUS_ADDRV | MCI_STATUS_MISCV | MCI_STATUS_PCC | + MCI_STATUS_AR | MCI_STATUS_S)) == + (MCI_STATUS_VAL | MCI_STATUS_UC | MCI_STATUS_EN | + MCI_STATUS_ADDRV | MCI_STATUS_MISCV | + MCI_STATUS_AR | MCI_STATUS_S)) { + misc_enable &= ~MSR_IA32_MISC_ENABLE_FAST_STRING; + mce_wrmsrl(MSR_IA32_MISC_ENABLE, misc_enable); + mce_wrmsrl(MSR_IA32_MCx_STATUS(1), 0); + + instrumentation_begin(); + pr_err_once("Erratum detected, disable fast string copy instructions.\n"); + instrumentation_end(); + + return true; + } + + return false; +} + +/* + * Some Zen-based Instruction Fetch Units set EIPV=RIPV=0 on poison consumption + * errors. This means mce_gather_info() will not save the "ip" and "cs" registers. + * + * However, the context is still valid, so save the "cs" register for later use. + * + * The "ip" register is truly unknown, so don't save it or fixup EIPV/RIPV. + * + * The Instruction Fetch Unit is at MCA bank 1 for all affected systems. + */ +static __always_inline void quirk_zen_ifu(int bank, struct mce *m, struct pt_regs *regs) +{ + if (bank != 1) + return; + if (!(m->status & MCI_STATUS_POISON)) + return; + + m->cs = regs->cs; +} + +/* + * Do a quick check if any of the events requires a panic. + * This decides if we keep the events around or clear them. + */ +static __always_inline int mce_no_way_out(struct mce *m, char **msg, unsigned long *validp, + struct pt_regs *regs) +{ + char *tmp = *msg; + int i; + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + m->status = mce_rdmsrl(mca_msr_reg(i, MCA_STATUS)); + if (!(m->status & MCI_STATUS_VAL)) + continue; + + arch___set_bit(i, validp); + if (mce_flags.snb_ifu_quirk) + quirk_sandybridge_ifu(i, m, regs); + + if (mce_flags.zen_ifu_quirk) + quirk_zen_ifu(i, m, regs); + + m->bank = i; + if (mce_severity(m, regs, &tmp, true) >= MCE_PANIC_SEVERITY) { + mce_read_aux(m, i); + *msg = tmp; + return 1; + } + } + return 0; +} + +/* + * 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; + +/* + * Track which CPUs entered the MCA broadcast synchronization and which not in + * order to print holdouts. + */ +static cpumask_t mce_missing_cpus = CPU_MASK_ALL; + +/* + * Check if a timeout waiting for other CPUs happened. + */ +static noinstr int mce_timed_out(u64 *t, const char *msg) +{ + int ret = 0; + + /* Enable instrumentation around calls to external facilities */ + instrumentation_begin(); + + /* + * 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 (cpumask_and(&mce_missing_cpus, cpu_online_mask, &mce_missing_cpus)) + pr_emerg("CPUs not responding to MCE broadcast (may include false positives): %*pbl\n", + cpumask_pr_args(&mce_missing_cpus)); + mce_panic(msg, NULL, NULL); + + ret = 1; + goto out; + } + *t -= SPINUNIT; + +out: + touch_nmi_watchdog(); + + instrumentation_end(); + + return ret; +} + +/* + * 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; + + /* + * 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) { + struct mce *mtmp = &per_cpu(mces_seen, cpu); + + if (mtmp->severity > global_worst) { + global_worst = mtmp->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) { + /* call mce_severity() to get "msg" for panic */ + mce_severity(m, NULL, &msg, true); + 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) + 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 noinstr int mce_start(int *no_way_out) +{ + u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC; + int order, ret = -1; + + if (!timeout) + return ret; + + raw_atomic_add(*no_way_out, &global_nwo); + /* + * Rely on the implied barrier below, such that global_nwo + * is updated before mce_callin. + */ + order = raw_atomic_inc_return(&mce_callin); + arch_cpumask_clear_cpu(smp_processor_id(), &mce_missing_cpus); + + /* Enable instrumentation around calls to external facilities */ + instrumentation_begin(); + + /* + * Wait for everyone. + */ + while (raw_atomic_read(&mce_callin) != num_online_cpus()) { + if (mce_timed_out(&timeout, + "Timeout: Not all CPUs entered broadcast exception handler")) { + raw_atomic_set(&global_nwo, 0); + goto out; + } + ndelay(SPINUNIT); + } + + /* + * mce_callin should be read before global_nwo + */ + smp_rmb(); + + if (order == 1) { + /* + * Monarch: Starts executing now, the others wait. + */ + raw_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 (raw_atomic_read(&mce_executing) < order) { + if (mce_timed_out(&timeout, + "Timeout: Subject CPUs unable to finish machine check processing")) { + raw_atomic_set(&global_nwo, 0); + goto out; + } + ndelay(SPINUNIT); + } + } + + /* + * Cache the global no_way_out state. + */ + *no_way_out = raw_atomic_read(&global_nwo); + + ret = order; + +out: + instrumentation_end(); + + return ret; +} + +/* + * Synchronize between CPUs after main scanning loop. + * This invokes the bulk of the Monarch processing. + */ +static noinstr int mce_end(int order) +{ + u64 timeout = (u64)mca_cfg.monarch_timeout * NSEC_PER_USEC; + int ret = -1; + + /* Allow instrumentation around external facilities. */ + instrumentation_begin(); + + if (!timeout) + goto reset; + if (order < 0) + goto reset; + + /* + * Allow others to run. + */ + atomic_inc(&mce_executing); + + if (order == 1) { + /* + * Monarch: Wait for everyone to go through their scanning + * loops. + */ + while (atomic_read(&mce_executing) <= num_online_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. + */ + ret = 0; + goto out; + } + + /* + * Reset all global state. + */ +reset: + atomic_set(&global_nwo, 0); + atomic_set(&mce_callin, 0); + cpumask_setall(&mce_missing_cpus); + barrier(); + + /* + * Let others run again. + */ + atomic_set(&mce_executing, 0); + +out: + instrumentation_end(); + + return ret; +} + +static __always_inline void mce_clear_state(unsigned long *toclear) +{ + int i; + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + if (arch_test_bit(i, toclear)) + mce_wrmsrl(mca_msr_reg(i, MCA_STATUS), 0); + } +} + +/* + * Cases where we avoid rendezvous handler timeout: + * 1) If this CPU is offline. + * + * 2) If crashing_cpu was set, e.g. we're entering kdump and we need to + * skip those CPUs which remain looping in the 1st kernel - see + * crash_nmi_callback(). + * + * Note: there still is a small window between kexec-ing and the new, + * kdump kernel establishing a new #MC handler where a broadcasted MCE + * might not get handled properly. + */ +static noinstr bool mce_check_crashing_cpu(void) +{ + unsigned int cpu = smp_processor_id(); + + if (arch_cpu_is_offline(cpu) || + (crashing_cpu != -1 && crashing_cpu != cpu)) { + u64 mcgstatus; + + mcgstatus = __rdmsr(MSR_IA32_MCG_STATUS); + + if (boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN) { + if (mcgstatus & MCG_STATUS_LMCES) + return false; + } + + if (mcgstatus & MCG_STATUS_RIPV) { + __wrmsr(MSR_IA32_MCG_STATUS, 0, 0); + return true; + } + } + return false; +} + +static __always_inline int +__mc_scan_banks(struct mce *m, struct pt_regs *regs, struct mce *final, + unsigned long *toclear, unsigned long *valid_banks, int no_way_out, + int *worst) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + struct mca_config *cfg = &mca_cfg; + int severity, i, taint = 0; + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + arch___clear_bit(i, toclear); + if (!arch_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(mca_msr_reg(i, MCA_STATUS)); + if (!(m->status & MCI_STATUS_VAL)) + continue; + + /* + * Corrected 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. */ + taint++; + + severity = mce_severity(m, regs, NULL, true); + + /* + * When machine check was for corrected/deferred handler don't + * touch, unless we're panicking. + */ + if ((severity == MCE_KEEP_SEVERITY || + severity == MCE_UCNA_SEVERITY) && !no_way_out) + continue; + + arch___set_bit(i, toclear); + + /* Machine check event was not enabled. Clear, but ignore. */ + if (severity == MCE_NO_SEVERITY) + continue; + + mce_read_aux(m, i); + + /* assuming valid severity level != 0 */ + m->severity = severity; + + /* + * Enable instrumentation around the mce_log() call which is + * done in #MC context, where instrumentation is disabled. + */ + instrumentation_begin(); + mce_log(m); + instrumentation_end(); + + if (severity > *worst) { + *final = *m; + *worst = severity; + } + } + + /* mce_clear_state will clear *final, save locally for use later */ + *m = *final; + + return taint; +} + +static void kill_me_now(struct callback_head *ch) +{ + struct task_struct *p = container_of(ch, struct task_struct, mce_kill_me); + + p->mce_count = 0; + force_sig(SIGBUS); +} + +static void kill_me_maybe(struct callback_head *cb) +{ + struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); + int flags = MF_ACTION_REQUIRED; + unsigned long pfn; + int ret; + + p->mce_count = 0; + pr_err("Uncorrected hardware memory error in user-access at %llx", p->mce_addr); + + if (!p->mce_ripv) + flags |= MF_MUST_KILL; + + pfn = (p->mce_addr & MCI_ADDR_PHYSADDR) >> PAGE_SHIFT; + ret = memory_failure(pfn, flags); + if (!ret) { + set_mce_nospec(pfn); + sync_core(); + return; + } + + /* + * -EHWPOISON from memory_failure() means that it already sent SIGBUS + * to the current process with the proper error info, + * -EOPNOTSUPP means hwpoison_filter() filtered the error event, + * + * In both cases, no further processing is required. + */ + if (ret == -EHWPOISON || ret == -EOPNOTSUPP) + return; + + pr_err("Memory error not recovered"); + kill_me_now(cb); +} + +static void kill_me_never(struct callback_head *cb) +{ + struct task_struct *p = container_of(cb, struct task_struct, mce_kill_me); + unsigned long pfn; + + p->mce_count = 0; + pr_err("Kernel accessed poison in user space at %llx\n", p->mce_addr); + pfn = (p->mce_addr & MCI_ADDR_PHYSADDR) >> PAGE_SHIFT; + if (!memory_failure(pfn, 0)) + set_mce_nospec(pfn); +} + +static void queue_task_work(struct mce *m, char *msg, void (*func)(struct callback_head *)) +{ + int count = ++current->mce_count; + + /* First call, save all the details */ + if (count == 1) { + current->mce_addr = m->addr; + current->mce_kflags = m->kflags; + current->mce_ripv = !!(m->mcgstatus & MCG_STATUS_RIPV); + current->mce_whole_page = whole_page(m); + current->mce_kill_me.func = func; + } + + /* Ten is likely overkill. Don't expect more than two faults before task_work() */ + if (count > 10) + mce_panic("Too many consecutive machine checks while accessing user data", m, msg); + + /* Second or later call, make sure page address matches the one from first call */ + if (count > 1 && (current->mce_addr >> PAGE_SHIFT) != (m->addr >> PAGE_SHIFT)) + mce_panic("Consecutive machine checks to different user pages", m, msg); + + /* Do not call task_work_add() more than once */ + if (count > 1) + return; + + task_work_add(current, ¤t->mce_kill_me, TWA_RESUME); +} + +/* Handle unconfigured int18 (should never happen) */ +static noinstr void unexpected_machine_check(struct pt_regs *regs) +{ + instrumentation_begin(); + pr_err("CPU#%d: Unexpected int18 (Machine Check)\n", + smp_processor_id()); + instrumentation_end(); +} + +/* + * The actual machine check handler. This only handles real exceptions when + * something got corrupted coming in through int 18. + * + * This is executed in #MC 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. + * + * Tracing and kprobes are disabled: if we interrupted a kernel context + * with IF=1, we need to minimize stack usage. There are also recursion + * issues: if the machine check was due to a failure of the memory + * backing the user stack, tracing that reads the user stack will cause + * potentially infinite recursion. + * + * Currently, the #MC handler calls out to a number of external facilities + * and, therefore, allows instrumentation around them. The optimal thing to + * have would be to do the absolutely minimal work required in #MC context + * and have instrumentation disabled only around that. Further processing can + * then happen in process context where instrumentation is allowed. Achieving + * that requires careful auditing and modifications. Until then, the code + * allows instrumentation temporarily, where required. * + */ +noinstr void do_machine_check(struct pt_regs *regs) +{ + int worst = 0, order, no_way_out, kill_current_task, lmce, taint = 0; + DECLARE_BITMAP(valid_banks, MAX_NR_BANKS) = { 0 }; + DECLARE_BITMAP(toclear, MAX_NR_BANKS) = { 0 }; + struct mce m, *final; + char *msg = NULL; + + if (unlikely(mce_flags.p5)) + return pentium_machine_check(regs); + else if (unlikely(mce_flags.winchip)) + return winchip_machine_check(regs); + else if (unlikely(!mca_cfg.initialized)) + return unexpected_machine_check(regs); + + if (mce_flags.skx_repmov_quirk && quirk_skylake_repmov()) + goto clear; + + /* + * Establish sequential order between the CPUs entering the machine + * check handler. + */ + order = -1; + + /* + * If no_way_out gets set, there is no safe way to recover from this + * MCE. + */ + no_way_out = 0; + + /* + * If kill_current_task is not set, there might be a way to recover from this + * error. + */ + kill_current_task = 0; + + /* + * MCEs are always local on AMD. Same is determined by MCG_STATUS_LMCES + * on Intel. + */ + lmce = 1; + + this_cpu_inc(mce_exception_count); + + mce_gather_info(&m, regs); + m.tsc = rdtsc(); + + final = this_cpu_ptr(&mces_seen); + *final = m; + + 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_current_task = 1; + /* + * Check if this MCE is signaled to only this logical processor, + * on Intel, Zhaoxin only. + */ + if (m.cpuvendor == X86_VENDOR_INTEL || + m.cpuvendor == X86_VENDOR_ZHAOXIN) + lmce = m.mcgstatus & MCG_STATUS_LMCES; + + /* + * Local machine check may already know that we have to panic. + * Broadcast machine check begins rendezvous in mce_start() + * Go through all 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. + */ + if (lmce) { + if (no_way_out) + mce_panic("Fatal local machine check", &m, msg); + } else { + order = mce_start(&no_way_out); + } + + taint = __mc_scan_banks(&m, regs, final, toclear, valid_banks, no_way_out, &worst); + + 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 (!lmce) { + if (mce_end(order) < 0) { + if (!no_way_out) + no_way_out = worst >= MCE_PANIC_SEVERITY; + + if (no_way_out) + mce_panic("Fatal machine check on current CPU", &m, msg); + } + } else { + /* + * If there was a fatal machine check we should have + * already called mce_panic earlier in this function. + * Since we re-read the banks, we might have found + * something new. Check again to see if we found a + * fatal error. We call "mce_severity()" again to + * make sure we have the right "msg". + */ + if (worst >= MCE_PANIC_SEVERITY) { + mce_severity(&m, regs, &msg, true); + mce_panic("Local fatal machine check!", &m, msg); + } + } + + /* + * Enable instrumentation around the external facilities like task_work_add() + * (via queue_task_work()), fixup_exception() etc. For now, that is. Fixing this + * properly would need a lot more involved reorganization. + */ + instrumentation_begin(); + + if (taint) + add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE); + + if (worst != MCE_AR_SEVERITY && !kill_current_task) + goto out; + + /* Fault was in user mode and we need to take some action */ + if ((m.cs & 3) == 3) { + /* If this triggers there is no way to recover. Die hard. */ + BUG_ON(!on_thread_stack() || !user_mode(regs)); + + if (!mce_usable_address(&m)) + queue_task_work(&m, msg, kill_me_now); + else + queue_task_work(&m, msg, kill_me_maybe); + + } else { + /* + * Handle an MCE which has happened in kernel space but from + * which the kernel can recover: ex_has_fault_handler() has + * already verified that the rIP at which the error happened is + * a rIP from which the kernel can recover (by jumping to + * recovery code specified in _ASM_EXTABLE_FAULT()) and the + * corresponding exception handler which would do that is the + * proper one. + */ + if (m.kflags & MCE_IN_KERNEL_RECOV) { + if (!fixup_exception(regs, X86_TRAP_MC, 0, 0)) + mce_panic("Failed kernel mode recovery", &m, msg); + } + + if (m.kflags & MCE_IN_KERNEL_COPYIN) + queue_task_work(&m, msg, kill_me_never); + } + +out: + instrumentation_end(); + +clear: + mce_wrmsrl(MSR_IA32_MCG_STATUS, 0); +} +EXPORT_SYMBOL_GPL(do_machine_check); + +#ifndef CONFIG_MEMORY_FAILURE +int memory_failure(unsigned long pfn, 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 + +/* + * 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 __start_timer(struct timer_list *t, unsigned long interval) +{ + unsigned long when = jiffies + interval; + unsigned long flags; + + local_irq_save(flags); + + if (!timer_pending(t) || time_before(when, t->expires)) + mod_timer(t, round_jiffies(when)); + + local_irq_restore(flags); +} + +static void mc_poll_banks_default(void) +{ + machine_check_poll(0, this_cpu_ptr(&mce_poll_banks)); +} + +void (*mc_poll_banks)(void) = mc_poll_banks_default; + +static void mce_timer_fn(struct timer_list *t) +{ + struct timer_list *cpu_t = this_cpu_ptr(&mce_timer); + unsigned long iv; + + WARN_ON(cpu_t != t); + + iv = __this_cpu_read(mce_next_interval); + + if (mce_available(this_cpu_ptr(&cpu_info))) { + mc_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); + __start_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); + + __start_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)); +} + +/* + * 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)) { + mce_work_trigger(); + + if (__ratelimit(&ratelimit)) + pr_info(HW_ERR "Machine check events logged\n"); + + return 1; + } + return 0; +} +EXPORT_SYMBOL_GPL(mce_notify_irq); + +static void __mcheck_cpu_mce_banks_init(void) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + u8 n_banks = this_cpu_read(mce_num_banks); + int i; + + for (i = 0; i < n_banks; i++) { + struct mce_bank *b = &mce_banks[i]; + + /* + * Init them all, __mcheck_cpu_apply_quirks() is going to apply + * the required vendor quirks before + * __mcheck_cpu_init_clear_banks() does the final bank setup. + */ + b->ctl = -1ULL; + b->init = true; + } +} + +/* + * Initialize Machine Checks for a CPU. + */ +static void __mcheck_cpu_cap_init(void) +{ + u64 cap; + u8 b; + + rdmsrl(MSR_IA32_MCG_CAP, cap); + + b = cap & MCG_BANKCNT_MASK; + + if (b > MAX_NR_BANKS) { + pr_warn("CPU%d: Using only %u machine check banks out of %u\n", + smp_processor_id(), MAX_NR_BANKS, b); + b = MAX_NR_BANKS; + } + + this_cpu_write(mce_num_banks, b); + + __mcheck_cpu_mce_banks_init(); + + /* 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 = 1; +} + +static void __mcheck_cpu_init_generic(void) +{ + enum mcp_flags m_fl = 0; + mce_banks_t all_banks; + u64 cap; + + if (!mca_cfg.bootlog) + m_fl = MCP_DONTLOG; + + /* + * Log the machine checks left over from the previous reset. Log them + * only, do not start processing them. That will happen in mcheck_late_init() + * when all consumers have been registered on the notifier chain. + */ + bitmap_fill(all_banks, MAX_NR_BANKS); + machine_check_poll(MCP_UC | MCP_QUEUE_LOG | 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); +} + +static void __mcheck_cpu_init_clear_banks(void) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + int i; + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + struct mce_bank *b = &mce_banks[i]; + + if (!b->init) + continue; + wrmsrl(mca_msr_reg(i, MCA_CTL), b->ctl); + wrmsrl(mca_msr_reg(i, MCA_STATUS), 0); + } +} + +/* + * Do a final check to see if there are any unused/RAZ banks. + * + * This must be done after the banks have been initialized and any quirks have + * been applied. + * + * Do not call this from any user-initiated flows, e.g. CPU hotplug or sysfs. + * Otherwise, a user who disables a bank will not be able to re-enable it + * without a system reboot. + */ +static void __mcheck_cpu_check_banks(void) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + u64 msrval; + int i; + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + struct mce_bank *b = &mce_banks[i]; + + if (!b->init) + continue; + + rdmsrl(mca_msr_reg(i, MCA_CTL), msrval); + b->init = !!msrval; + } +} + +/* Add per CPU specific workarounds here */ +static int __mcheck_cpu_apply_quirks(struct cpuinfo_x86 *c) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + 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 && this_cpu_read(mce_num_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 < 0x11 && 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 && this_cpu_read(mce_num_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; + + if (c->x86 >= 0x17 && c->x86 <= 0x1A) + mce_flags.zen_ifu_quirk = 1; + + } + + 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 && this_cpu_read(mce_num_banks) > 0) + mce_banks[0].init = false; + + /* + * 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) + mce_flags.snb_ifu_quirk = 1; + + /* + * Skylake, Cascacde Lake and Cooper Lake require a quirk on + * rep movs. + */ + if (c->x86 == 6 && c->x86_model == INTEL_FAM6_SKYLAKE_X) + mce_flags.skx_repmov_quirk = 1; + } + + if (c->x86_vendor == X86_VENDOR_ZHAOXIN) { + /* + * All newer Zhaoxin CPUs support MCE broadcasting. Enable + * synchronization with a one second timeout. + */ + if (c->x86 > 6 || (c->x86_model == 0x19 || c->x86_model == 0x1f)) { + if (cfg->monarch_timeout < 0) + cfg->monarch_timeout = USEC_PER_SEC; + } + } + + 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); + mce_flags.p5 = 1; + return 1; + case X86_VENDOR_CENTAUR: + winchip_mcheck_init(c); + mce_flags.winchip = 1; + return 1; + default: + return 0; + } + + return 0; +} + +/* + * Init basic CPU features needed for early decoding of MCEs. + */ +static void __mcheck_cpu_init_early(struct cpuinfo_x86 *c) +{ + if (c->x86_vendor == X86_VENDOR_AMD || c->x86_vendor == X86_VENDOR_HYGON) { + mce_flags.overflow_recov = !!cpu_has(c, X86_FEATURE_OVERFLOW_RECOV); + mce_flags.succor = !!cpu_has(c, X86_FEATURE_SUCCOR); + mce_flags.smca = !!cpu_has(c, X86_FEATURE_SMCA); + mce_flags.amd_threshold = 1; + } +} + +static void mce_centaur_feature_init(struct cpuinfo_x86 *c) +{ + struct mca_config *cfg = &mca_cfg; + + /* + * All newer Centaur CPUs support MCE broadcasting. Enable + * synchronization with a one second timeout. + */ + if ((c->x86 == 6 && c->x86_model == 0xf && c->x86_stepping >= 0xe) || + c->x86 > 6) { + if (cfg->monarch_timeout < 0) + cfg->monarch_timeout = USEC_PER_SEC; + } +} + +static void mce_zhaoxin_feature_init(struct cpuinfo_x86 *c) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + + /* + * These CPUs have MCA bank 8 which reports only one error type called + * SVAD (System View Address Decoder). The reporting of that error is + * controlled by IA32_MC8.CTL.0. + * + * If enabled, prefetching on these CPUs will cause SVAD MCE when + * virtual machines start and result in a system panic. Always disable + * bank 8 SVAD error by default. + */ + if ((c->x86 == 7 && c->x86_model == 0x1b) || + (c->x86_model == 0x19 || c->x86_model == 0x1f)) { + if (this_cpu_read(mce_num_banks) > 8) + mce_banks[8].ctl = 0; + } + + intel_init_cmci(); + intel_init_lmce(); + mce_adjust_timer = cmci_intel_adjust_timer; +} + +static void mce_zhaoxin_feature_clear(struct cpuinfo_x86 *c) +{ + intel_clear_lmce(); +} + +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); + break; + } + + case X86_VENDOR_HYGON: + mce_hygon_feature_init(c); + break; + + case X86_VENDOR_CENTAUR: + mce_centaur_feature_init(c); + break; + + case X86_VENDOR_ZHAOXIN: + mce_zhaoxin_feature_init(c); + break; + + default: + break; + } +} + +static void __mcheck_cpu_clear_vendor(struct cpuinfo_x86 *c) +{ + switch (c->x86_vendor) { + case X86_VENDOR_INTEL: + mce_intel_feature_clear(c); + break; + + case X86_VENDOR_ZHAOXIN: + mce_zhaoxin_feature_clear(c); + break; + + default: + break; + } +} + +static void mce_start_timer(struct timer_list *t) +{ + unsigned long iv = check_interval * HZ; + + if (mca_cfg.ignore_ce || !iv) + return; + + this_cpu_write(mce_next_interval, iv); + __start_timer(t, iv); +} + +static void __mcheck_cpu_setup_timer(void) +{ + struct timer_list *t = this_cpu_ptr(&mce_timer); + + timer_setup(t, mce_timer_fn, TIMER_PINNED); +} + +static void __mcheck_cpu_init_timer(void) +{ + struct timer_list *t = this_cpu_ptr(&mce_timer); + + timer_setup(t, mce_timer_fn, TIMER_PINNED); + mce_start_timer(t); +} + +bool filter_mce(struct mce *m) +{ + if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) + return amd_filter_mce(m); + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) + return intel_filter_mce(m); + + return false; +} + +static __always_inline void exc_machine_check_kernel(struct pt_regs *regs) +{ + irqentry_state_t irq_state; + + WARN_ON_ONCE(user_mode(regs)); + + /* + * Only required when from kernel mode. See + * mce_check_crashing_cpu() for details. + */ + if (mca_cfg.initialized && mce_check_crashing_cpu()) + return; + + irq_state = irqentry_nmi_enter(regs); + + do_machine_check(regs); + + irqentry_nmi_exit(regs, irq_state); +} + +static __always_inline void exc_machine_check_user(struct pt_regs *regs) +{ + irqentry_enter_from_user_mode(regs); + + do_machine_check(regs); + + irqentry_exit_to_user_mode(regs); +} + +#ifdef CONFIG_X86_64 +/* MCE hit kernel mode */ +DEFINE_IDTENTRY_MCE(exc_machine_check) +{ + unsigned long dr7; + + dr7 = local_db_save(); + exc_machine_check_kernel(regs); + local_db_restore(dr7); +} + +/* The user mode variant. */ +DEFINE_IDTENTRY_MCE_USER(exc_machine_check) +{ + unsigned long dr7; + + dr7 = local_db_save(); + exc_machine_check_user(regs); + local_db_restore(dr7); +} +#else +/* 32bit unified entry point */ +DEFINE_IDTENTRY_RAW(exc_machine_check) +{ + unsigned long dr7; + + dr7 = local_db_save(); + if (user_mode(regs)) + exc_machine_check_user(regs); + else + exc_machine_check_kernel(regs); + local_db_restore(dr7); +} +#endif + +/* + * 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; + + __mcheck_cpu_cap_init(); + + if (__mcheck_cpu_apply_quirks(c) < 0) { + mca_cfg.disabled = 1; + return; + } + + if (mce_gen_pool_init()) { + mca_cfg.disabled = 1; + pr_emerg("Couldn't allocate MCE records pool!\n"); + return; + } + + mca_cfg.initialized = 1; + + __mcheck_cpu_init_early(c); + __mcheck_cpu_init_generic(); + __mcheck_cpu_init_vendor(c); + __mcheck_cpu_init_clear_banks(); + __mcheck_cpu_check_banks(); + __mcheck_cpu_setup_timer(); +} + +/* + * Called for each booted CPU to clear some machine checks opt-ins + */ +void mcheck_cpu_clear(struct cpuinfo_x86 *c) +{ + if (mca_cfg.disabled) + return; + + if (!mce_available(c)) + return; + + /* + * Possibly to clear general settings generic to x86 + * __mcheck_cpu_clear_generic(c); + */ + __mcheck_cpu_clear_vendor(c); + +} + +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 >= this_cpu_read(mce_num_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=no_lmce Disables LMCE + * mce=dont_log_ce Clears corrected events silently, no log created for CEs. + * mce=print_all Print all machine check logs to console + * 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 Fam10h + and older. + * mce=nobootlog Don't log MCEs from before booting. + * mce=bios_cmci_threshold Don't program the CMCI threshold + * mce=recovery force enable copy_mc_fragile() + */ +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 = 1; + else if (!strcmp(str, "no_cmci")) + cfg->cmci_disabled = true; + else if (!strcmp(str, "no_lmce")) + cfg->lmce_disabled = 1; + else if (!strcmp(str, "dont_log_ce")) + cfg->dont_log_ce = true; + else if (!strcmp(str, "print_all")) + cfg->print_all = 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 = 1; + else if (!strcmp(str, "recovery")) + cfg->recovery = 1; + else if (isdigit(str[0])) + 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) +{ + mce_register_decode_chain(&early_nb); + mce_register_decode_chain(&mce_uc_nb); + mce_register_decode_chain(&mce_default_nb); + + INIT_WORK(&mce_work, mce_gen_pool_process); + init_irq_work(&mce_irq_work, mce_irq_work_cb); + + return 0; +} + +/* + * mce_syscore: PM support + */ + +/* + * Disable machine checks on suspend and shutdown. We can't really handle + * them later. + */ +static void mce_disable_error_reporting(void) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + int i; + + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + struct mce_bank *b = &mce_banks[i]; + + if (b->init) + wrmsrl(mca_msr_reg(i, MCA_CTL), 0); + } + return; +} + +static void vendor_disable_error_reporting(void) +{ + /* + * Don't clear on Intel or AMD or Hygon or Zhaoxin CPUs. Some of these + * MSRs are socket-wide. Disabling them for just a single offlined CPU + * is bad, since it will inhibit reporting for all shared resources on + * the socket like the last level cache (LLC), the integrated memory + * controller (iMC), etc. + */ + if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL || + boot_cpu_data.x86_vendor == X86_VENDOR_HYGON || + boot_cpu_data.x86_vendor == X86_VENDOR_AMD || + boot_cpu_data.x86_vendor == X86_VENDOR_ZHAOXIN) + return; + + mce_disable_error_reporting(); +} + +static int mce_syscore_suspend(void) +{ + vendor_disable_error_reporting(); + return 0; +} + +static void mce_syscore_shutdown(void) +{ + vendor_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)); + __mcheck_cpu_init_clear_banks(); +} + +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_clear_banks(); + __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); + mce_schedule_work(); +} + +/* 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); + +static inline struct mce_bank_dev *attr_to_bank(struct device_attribute *attr) +{ + return container_of(attr, struct mce_bank_dev, attr); +} + +static ssize_t show_bank(struct device *s, struct device_attribute *attr, + char *buf) +{ + u8 bank = attr_to_bank(attr)->bank; + struct mce_bank *b; + + if (bank >= per_cpu(mce_num_banks, s->id)) + return -EINVAL; + + b = &per_cpu(mce_banks_array, s->id)[bank]; + + if (!b->init) + return -ENODEV; + + return sprintf(buf, "%llx\n", b->ctl); +} + +static ssize_t set_bank(struct device *s, struct device_attribute *attr, + const char *buf, size_t size) +{ + u8 bank = attr_to_bank(attr)->bank; + struct mce_bank *b; + u64 new; + + if (kstrtou64(buf, 0, &new) < 0) + return -EINVAL; + + if (bank >= per_cpu(mce_num_banks, s->id)) + return -EINVAL; + + b = &per_cpu(mce_banks_array, s->id)[bank]; + + if (!b->init) + return -ENODEV; + + b->ctl = new; + mce_restart(); + + return size; +} + +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; + + mutex_lock(&mce_sysfs_mutex); + 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); + } + } + mutex_unlock(&mce_sysfs_mutex); + + 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; + + mutex_lock(&mce_sysfs_mutex); + 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); + } + } + mutex_unlock(&mce_sysfs_mutex); + + return size; +} + +static ssize_t store_int_with_restart(struct device *s, + struct device_attribute *attr, + const char *buf, size_t size) +{ + unsigned long old_check_interval = check_interval; + ssize_t ret = device_store_ulong(s, attr, buf, size); + + if (check_interval == old_check_interval) + return ret; + + mutex_lock(&mce_sysfs_mutex); + mce_restart(); + mutex_unlock(&mce_sysfs_mutex); + + return ret; +} + +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 DEVICE_BOOL_ATTR(print_all, 0644, mca_cfg.print_all); + +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_check_interval.attr, +#ifdef CONFIG_X86_MCELOG_LEGACY + &dev_attr_trigger, +#endif + &dev_attr_monarch_timeout.attr, + &dev_attr_dont_log_ce.attr, + &dev_attr_print_all.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 bank device: */ +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 = per_cpu(mce_device, cpu); + if (dev) + return 0; + + 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 < per_cpu(mce_num_banks, cpu); j++) { + err = device_create_file(dev, &mce_bank_devs[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_bank_devs[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 < per_cpu(mce_num_banks, cpu); i++) + device_remove_file(dev, &mce_bank_devs[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) +{ + if (!mce_available(raw_cpu_ptr(&cpu_info))) + return; + + if (!cpuhp_tasks_frozen) + cmci_clear(); + + vendor_disable_error_reporting(); +} + +static void mce_reenable_cpu(void) +{ + struct mce_bank *mce_banks = this_cpu_ptr(mce_banks_array); + int i; + + if (!mce_available(raw_cpu_ptr(&cpu_info))) + return; + + if (!cpuhp_tasks_frozen) + cmci_reenable(); + for (i = 0; i < this_cpu_read(mce_num_banks); i++) { + struct mce_bank *b = &mce_banks[i]; + + if (b->init) + wrmsrl(mca_msr_reg(i, MCA_CTL), b->ctl); + } +} + +static int mce_cpu_dead(unsigned int cpu) +{ + mce_intel_hcpu_update(cpu); + + /* intentionally ignoring frozen here */ + if (!cpuhp_tasks_frozen) + cmci_rediscover(); + return 0; +} + +static int mce_cpu_online(unsigned int cpu) +{ + struct timer_list *t = this_cpu_ptr(&mce_timer); + int ret; + + mce_device_create(cpu); + + ret = mce_threshold_create_device(cpu); + if (ret) { + mce_device_remove(cpu); + return ret; + } + mce_reenable_cpu(); + mce_start_timer(t); + return 0; +} + +static int mce_cpu_pre_down(unsigned int cpu) +{ + struct timer_list *t = this_cpu_ptr(&mce_timer); + + mce_disable_cpu(); + del_timer_sync(t); + mce_threshold_remove_device(cpu); + mce_device_remove(cpu); + return 0; +} + +static __init void mce_init_banks(void) +{ + int i; + + for (i = 0; i < MAX_NR_BANKS; i++) { + struct mce_bank_dev *b = &mce_bank_devs[i]; + struct device_attribute *a = &b->attr; + + b->bank = i; + + 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; + } +} + +/* + * When running on XEN, this initcall is ordered against the XEN mcelog + * initcall: + * + * device_initcall(xen_late_init_mcelog); + * device_initcall_sync(mcheck_init_device); + */ +static __init int mcheck_init_device(void) +{ + int err; + + /* + * Check if we have a spare virtual bit. This will only become + * a problem if/when we move beyond 5-level page tables. + */ + MAYBE_BUILD_BUG_ON(__VIRTUAL_MASK_SHIFT >= 63); + + 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; + + err = cpuhp_setup_state(CPUHP_X86_MCE_DEAD, "x86/mce:dead", NULL, + mce_cpu_dead); + if (err) + goto err_out_mem; + + /* + * Invokes mce_cpu_online() on all CPUs which are online when + * the state is installed. + */ + err = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/mce:online", + mce_cpu_online, mce_cpu_pre_down); + if (err < 0) + goto err_out_online; + + register_syscore_ops(&mce_syscore_ops); + + return 0; + +err_out_online: + cpuhp_remove_state(CPUHP_X86_MCE_DEAD); + +err_out_mem: + free_cpumask_var(mce_device_initialized); + +err_out: + pr_err("Unable to init MCE device (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 = 1; + 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) +{ + atomic_set(&mce_fake_panicked, 0); + atomic_set(&mce_executing, 0); + atomic_set(&mce_callin, 0); + atomic_set(&global_nwo, 0); + cpumask_setall(&mce_missing_cpus); +} + +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_DEBUGFS_ATTRIBUTE(fake_panic_fops, fake_panic_get, fake_panic_set, + "%llu\n"); + +static void __init mcheck_debugfs_init(void) +{ + struct dentry *dmce; + + dmce = mce_get_debugfs_dir(); + debugfs_create_file_unsafe("fake_panic", 0444, dmce, NULL, + &fake_panic_fops); +} +#else +static void __init mcheck_debugfs_init(void) { } +#endif + +static int __init mcheck_late_init(void) +{ + if (mca_cfg.recovery) + enable_copy_mc_fragile(); + + mcheck_debugfs_init(); + + /* + * Flush out everything that has been logged during early boot, now that + * everything has been initialized (workqueues, decoders, ...). + */ + mce_schedule_work(); + + return 0; +} +late_initcall(mcheck_late_init); |