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-rw-r--r--arch/x86/kernel/cpu/mce/intel.c521
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diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
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+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel specific MCE features.
+ * Copyright 2004 Zwane Mwaikambo <zwane@linuxpower.ca>
+ * Copyright (C) 2008, 2009 Intel Corporation
+ * Author: Andi Kleen
+ */
+
+#include <linux/gfp.h>
+#include <linux/interrupt.h>
+#include <linux/percpu.h>
+#include <linux/sched.h>
+#include <linux/cpumask.h>
+#include <asm/apic.h>
+#include <asm/cpufeature.h>
+#include <asm/intel-family.h>
+#include <asm/processor.h>
+#include <asm/msr.h>
+#include <asm/mce.h>
+
+#include "internal.h"
+
+/*
+ * Support for Intel Correct Machine Check Interrupts. This allows
+ * the CPU to raise an interrupt when a corrected machine check happened.
+ * Normally we pick those up using a regular polling timer.
+ * Also supports reliable discovery of shared banks.
+ */
+
+/*
+ * CMCI can be delivered to multiple cpus that share a machine check bank
+ * so we need to designate a single cpu to process errors logged in each bank
+ * in the interrupt handler (otherwise we would have many races and potential
+ * double reporting of the same error).
+ * Note that this can change when a cpu is offlined or brought online since
+ * some MCA banks are shared across cpus. When a cpu is offlined, cmci_clear()
+ * disables CMCI on all banks owned by the cpu and clears this bitfield. At
+ * this point, cmci_rediscover() kicks in and a different cpu may end up
+ * taking ownership of some of the shared MCA banks that were previously
+ * owned by the offlined cpu.
+ */
+static DEFINE_PER_CPU(mce_banks_t, mce_banks_owned);
+
+/*
+ * CMCI storm detection backoff counter
+ *
+ * During storm, we reset this counter to INITIAL_CHECK_INTERVAL in case we've
+ * encountered an error. If not, we decrement it by one. We signal the end of
+ * the CMCI storm when it reaches 0.
+ */
+static DEFINE_PER_CPU(int, cmci_backoff_cnt);
+
+/*
+ * cmci_discover_lock protects against parallel discovery attempts
+ * which could race against each other.
+ */
+static DEFINE_RAW_SPINLOCK(cmci_discover_lock);
+
+#define CMCI_THRESHOLD 1
+#define CMCI_POLL_INTERVAL (30 * HZ)
+#define CMCI_STORM_INTERVAL (HZ)
+#define CMCI_STORM_THRESHOLD 15
+
+static DEFINE_PER_CPU(unsigned long, cmci_time_stamp);
+static DEFINE_PER_CPU(unsigned int, cmci_storm_cnt);
+static DEFINE_PER_CPU(unsigned int, cmci_storm_state);
+
+enum {
+ CMCI_STORM_NONE,
+ CMCI_STORM_ACTIVE,
+ CMCI_STORM_SUBSIDED,
+};
+
+static atomic_t cmci_storm_on_cpus;
+
+static int cmci_supported(int *banks)
+{
+ u64 cap;
+
+ if (mca_cfg.cmci_disabled || mca_cfg.ignore_ce)
+ return 0;
+
+ /*
+ * Vendor check is not strictly needed, but the initial
+ * initialization is vendor keyed and this
+ * makes sure none of the backdoors are entered otherwise.
+ */
+ if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL &&
+ boot_cpu_data.x86_vendor != X86_VENDOR_ZHAOXIN)
+ return 0;
+
+ if (!boot_cpu_has(X86_FEATURE_APIC) || lapic_get_maxlvt() < 6)
+ return 0;
+ rdmsrl(MSR_IA32_MCG_CAP, cap);
+ *banks = min_t(unsigned, MAX_NR_BANKS, cap & 0xff);
+ return !!(cap & MCG_CMCI_P);
+}
+
+static bool lmce_supported(void)
+{
+ u64 tmp;
+
+ if (mca_cfg.lmce_disabled)
+ return false;
+
+ rdmsrl(MSR_IA32_MCG_CAP, tmp);
+
+ /*
+ * LMCE depends on recovery support in the processor. Hence both
+ * MCG_SER_P and MCG_LMCE_P should be present in MCG_CAP.
+ */
+ if ((tmp & (MCG_SER_P | MCG_LMCE_P)) !=
+ (MCG_SER_P | MCG_LMCE_P))
+ return false;
+
+ /*
+ * BIOS should indicate support for LMCE by setting bit 20 in
+ * IA32_FEAT_CTL without which touching MCG_EXT_CTL will generate a #GP
+ * fault. The MSR must also be locked for LMCE_ENABLED to take effect.
+ * WARN if the MSR isn't locked as init_ia32_feat_ctl() unconditionally
+ * locks the MSR in the event that it wasn't already locked by BIOS.
+ */
+ rdmsrl(MSR_IA32_FEAT_CTL, tmp);
+ if (WARN_ON_ONCE(!(tmp & FEAT_CTL_LOCKED)))
+ return false;
+
+ return tmp & FEAT_CTL_LMCE_ENABLED;
+}
+
+bool mce_intel_cmci_poll(void)
+{
+ if (__this_cpu_read(cmci_storm_state) == CMCI_STORM_NONE)
+ return false;
+
+ /*
+ * Reset the counter if we've logged an error in the last poll
+ * during the storm.
+ */
+ if (machine_check_poll(0, this_cpu_ptr(&mce_banks_owned)))
+ this_cpu_write(cmci_backoff_cnt, INITIAL_CHECK_INTERVAL);
+ else
+ this_cpu_dec(cmci_backoff_cnt);
+
+ return true;
+}
+
+void mce_intel_hcpu_update(unsigned long cpu)
+{
+ if (per_cpu(cmci_storm_state, cpu) == CMCI_STORM_ACTIVE)
+ atomic_dec(&cmci_storm_on_cpus);
+
+ per_cpu(cmci_storm_state, cpu) = CMCI_STORM_NONE;
+}
+
+static void cmci_toggle_interrupt_mode(bool on)
+{
+ unsigned long flags, *owned;
+ int bank;
+ u64 val;
+
+ raw_spin_lock_irqsave(&cmci_discover_lock, flags);
+ owned = this_cpu_ptr(mce_banks_owned);
+ for_each_set_bit(bank, owned, MAX_NR_BANKS) {
+ rdmsrl(MSR_IA32_MCx_CTL2(bank), val);
+
+ if (on)
+ val |= MCI_CTL2_CMCI_EN;
+ else
+ val &= ~MCI_CTL2_CMCI_EN;
+
+ wrmsrl(MSR_IA32_MCx_CTL2(bank), val);
+ }
+ raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
+}
+
+unsigned long cmci_intel_adjust_timer(unsigned long interval)
+{
+ if ((this_cpu_read(cmci_backoff_cnt) > 0) &&
+ (__this_cpu_read(cmci_storm_state) == CMCI_STORM_ACTIVE)) {
+ mce_notify_irq();
+ return CMCI_STORM_INTERVAL;
+ }
+
+ switch (__this_cpu_read(cmci_storm_state)) {
+ case CMCI_STORM_ACTIVE:
+
+ /*
+ * We switch back to interrupt mode once the poll timer has
+ * silenced itself. That means no events recorded and the timer
+ * interval is back to our poll interval.
+ */
+ __this_cpu_write(cmci_storm_state, CMCI_STORM_SUBSIDED);
+ if (!atomic_sub_return(1, &cmci_storm_on_cpus))
+ pr_notice("CMCI storm subsided: switching to interrupt mode\n");
+
+ fallthrough;
+
+ case CMCI_STORM_SUBSIDED:
+ /*
+ * We wait for all CPUs to go back to SUBSIDED state. When that
+ * happens we switch back to interrupt mode.
+ */
+ if (!atomic_read(&cmci_storm_on_cpus)) {
+ __this_cpu_write(cmci_storm_state, CMCI_STORM_NONE);
+ cmci_toggle_interrupt_mode(true);
+ cmci_recheck();
+ }
+ return CMCI_POLL_INTERVAL;
+ default:
+
+ /* We have shiny weather. Let the poll do whatever it thinks. */
+ return interval;
+ }
+}
+
+static bool cmci_storm_detect(void)
+{
+ unsigned int cnt = __this_cpu_read(cmci_storm_cnt);
+ unsigned long ts = __this_cpu_read(cmci_time_stamp);
+ unsigned long now = jiffies;
+ int r;
+
+ if (__this_cpu_read(cmci_storm_state) != CMCI_STORM_NONE)
+ return true;
+
+ if (time_before_eq(now, ts + CMCI_STORM_INTERVAL)) {
+ cnt++;
+ } else {
+ cnt = 1;
+ __this_cpu_write(cmci_time_stamp, now);
+ }
+ __this_cpu_write(cmci_storm_cnt, cnt);
+
+ if (cnt <= CMCI_STORM_THRESHOLD)
+ return false;
+
+ cmci_toggle_interrupt_mode(false);
+ __this_cpu_write(cmci_storm_state, CMCI_STORM_ACTIVE);
+ r = atomic_add_return(1, &cmci_storm_on_cpus);
+ mce_timer_kick(CMCI_STORM_INTERVAL);
+ this_cpu_write(cmci_backoff_cnt, INITIAL_CHECK_INTERVAL);
+
+ if (r == 1)
+ pr_notice("CMCI storm detected: switching to poll mode\n");
+ return true;
+}
+
+/*
+ * The interrupt handler. This is called on every event.
+ * Just call the poller directly to log any events.
+ * This could in theory increase the threshold under high load,
+ * but doesn't for now.
+ */
+static void intel_threshold_interrupt(void)
+{
+ if (cmci_storm_detect())
+ return;
+
+ machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_banks_owned));
+}
+
+/*
+ * Enable CMCI (Corrected Machine Check Interrupt) for available MCE banks
+ * on this CPU. Use the algorithm recommended in the SDM to discover shared
+ * banks.
+ */
+static void cmci_discover(int banks)
+{
+ unsigned long *owned = (void *)this_cpu_ptr(&mce_banks_owned);
+ unsigned long flags;
+ int i;
+ int bios_wrong_thresh = 0;
+
+ raw_spin_lock_irqsave(&cmci_discover_lock, flags);
+ for (i = 0; i < banks; i++) {
+ u64 val;
+ int bios_zero_thresh = 0;
+
+ if (test_bit(i, owned))
+ continue;
+
+ /* Skip banks in firmware first mode */
+ if (test_bit(i, mce_banks_ce_disabled))
+ continue;
+
+ rdmsrl(MSR_IA32_MCx_CTL2(i), val);
+
+ /* Already owned by someone else? */
+ if (val & MCI_CTL2_CMCI_EN) {
+ clear_bit(i, owned);
+ __clear_bit(i, this_cpu_ptr(mce_poll_banks));
+ continue;
+ }
+
+ if (!mca_cfg.bios_cmci_threshold) {
+ val &= ~MCI_CTL2_CMCI_THRESHOLD_MASK;
+ val |= CMCI_THRESHOLD;
+ } else if (!(val & MCI_CTL2_CMCI_THRESHOLD_MASK)) {
+ /*
+ * If bios_cmci_threshold boot option was specified
+ * but the threshold is zero, we'll try to initialize
+ * it to 1.
+ */
+ bios_zero_thresh = 1;
+ val |= CMCI_THRESHOLD;
+ }
+
+ val |= MCI_CTL2_CMCI_EN;
+ wrmsrl(MSR_IA32_MCx_CTL2(i), val);
+ rdmsrl(MSR_IA32_MCx_CTL2(i), val);
+
+ /* Did the enable bit stick? -- the bank supports CMCI */
+ if (val & MCI_CTL2_CMCI_EN) {
+ set_bit(i, owned);
+ __clear_bit(i, this_cpu_ptr(mce_poll_banks));
+ /*
+ * We are able to set thresholds for some banks that
+ * had a threshold of 0. This means the BIOS has not
+ * set the thresholds properly or does not work with
+ * this boot option. Note down now and report later.
+ */
+ if (mca_cfg.bios_cmci_threshold && bios_zero_thresh &&
+ (val & MCI_CTL2_CMCI_THRESHOLD_MASK))
+ bios_wrong_thresh = 1;
+ } else {
+ WARN_ON(!test_bit(i, this_cpu_ptr(mce_poll_banks)));
+ }
+ }
+ raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
+ if (mca_cfg.bios_cmci_threshold && bios_wrong_thresh) {
+ pr_info_once(
+ "bios_cmci_threshold: Some banks do not have valid thresholds set\n");
+ pr_info_once(
+ "bios_cmci_threshold: Make sure your BIOS supports this boot option\n");
+ }
+}
+
+/*
+ * Just in case we missed an event during initialization check
+ * all the CMCI owned banks.
+ */
+void cmci_recheck(void)
+{
+ unsigned long flags;
+ int banks;
+
+ if (!mce_available(raw_cpu_ptr(&cpu_info)) || !cmci_supported(&banks))
+ return;
+
+ local_irq_save(flags);
+ machine_check_poll(0, this_cpu_ptr(&mce_banks_owned));
+ local_irq_restore(flags);
+}
+
+/* Caller must hold the lock on cmci_discover_lock */
+static void __cmci_disable_bank(int bank)
+{
+ u64 val;
+
+ if (!test_bit(bank, this_cpu_ptr(mce_banks_owned)))
+ return;
+ rdmsrl(MSR_IA32_MCx_CTL2(bank), val);
+ val &= ~MCI_CTL2_CMCI_EN;
+ wrmsrl(MSR_IA32_MCx_CTL2(bank), val);
+ __clear_bit(bank, this_cpu_ptr(mce_banks_owned));
+}
+
+/*
+ * Disable CMCI on this CPU for all banks it owns when it goes down.
+ * This allows other CPUs to claim the banks on rediscovery.
+ */
+void cmci_clear(void)
+{
+ unsigned long flags;
+ int i;
+ int banks;
+
+ if (!cmci_supported(&banks))
+ return;
+ raw_spin_lock_irqsave(&cmci_discover_lock, flags);
+ for (i = 0; i < banks; i++)
+ __cmci_disable_bank(i);
+ raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
+}
+
+static void cmci_rediscover_work_func(void *arg)
+{
+ int banks;
+
+ /* Recheck banks in case CPUs don't all have the same */
+ if (cmci_supported(&banks))
+ cmci_discover(banks);
+}
+
+/* After a CPU went down cycle through all the others and rediscover */
+void cmci_rediscover(void)
+{
+ int banks;
+
+ if (!cmci_supported(&banks))
+ return;
+
+ on_each_cpu(cmci_rediscover_work_func, NULL, 1);
+}
+
+/*
+ * Reenable CMCI on this CPU in case a CPU down failed.
+ */
+void cmci_reenable(void)
+{
+ int banks;
+ if (cmci_supported(&banks))
+ cmci_discover(banks);
+}
+
+void cmci_disable_bank(int bank)
+{
+ int banks;
+ unsigned long flags;
+
+ if (!cmci_supported(&banks))
+ return;
+
+ raw_spin_lock_irqsave(&cmci_discover_lock, flags);
+ __cmci_disable_bank(bank);
+ raw_spin_unlock_irqrestore(&cmci_discover_lock, flags);
+}
+
+void intel_init_cmci(void)
+{
+ int banks;
+
+ if (!cmci_supported(&banks))
+ return;
+
+ mce_threshold_vector = intel_threshold_interrupt;
+ cmci_discover(banks);
+ /*
+ * For CPU #0 this runs with still disabled APIC, but that's
+ * ok because only the vector is set up. We still do another
+ * check for the banks later for CPU #0 just to make sure
+ * to not miss any events.
+ */
+ apic_write(APIC_LVTCMCI, THRESHOLD_APIC_VECTOR|APIC_DM_FIXED);
+ cmci_recheck();
+}
+
+void intel_init_lmce(void)
+{
+ u64 val;
+
+ if (!lmce_supported())
+ return;
+
+ rdmsrl(MSR_IA32_MCG_EXT_CTL, val);
+
+ if (!(val & MCG_EXT_CTL_LMCE_EN))
+ wrmsrl(MSR_IA32_MCG_EXT_CTL, val | MCG_EXT_CTL_LMCE_EN);
+}
+
+void intel_clear_lmce(void)
+{
+ u64 val;
+
+ if (!lmce_supported())
+ return;
+
+ rdmsrl(MSR_IA32_MCG_EXT_CTL, val);
+ val &= ~MCG_EXT_CTL_LMCE_EN;
+ wrmsrl(MSR_IA32_MCG_EXT_CTL, val);
+}
+
+/*
+ * Enable additional error logs from the integrated
+ * memory controller on processors that support this.
+ */
+static void intel_imc_init(struct cpuinfo_x86 *c)
+{
+ u64 error_control;
+
+ switch (c->x86_model) {
+ case INTEL_FAM6_SANDYBRIDGE_X:
+ case INTEL_FAM6_IVYBRIDGE_X:
+ case INTEL_FAM6_HASWELL_X:
+ if (rdmsrl_safe(MSR_ERROR_CONTROL, &error_control))
+ return;
+ error_control |= 2;
+ wrmsrl_safe(MSR_ERROR_CONTROL, error_control);
+ break;
+ }
+}
+
+void mce_intel_feature_init(struct cpuinfo_x86 *c)
+{
+ intel_init_cmci();
+ intel_init_lmce();
+ intel_imc_init(c);
+}
+
+void mce_intel_feature_clear(struct cpuinfo_x86 *c)
+{
+ intel_clear_lmce();
+}
+
+bool intel_filter_mce(struct mce *m)
+{
+ struct cpuinfo_x86 *c = &boot_cpu_data;
+
+ /* MCE errata HSD131, HSM142, HSW131, BDM48, HSM142 and SKX37 */
+ if ((c->x86 == 6) &&
+ ((c->x86_model == INTEL_FAM6_HASWELL) ||
+ (c->x86_model == INTEL_FAM6_HASWELL_L) ||
+ (c->x86_model == INTEL_FAM6_BROADWELL) ||
+ (c->x86_model == INTEL_FAM6_HASWELL_G) ||
+ (c->x86_model == INTEL_FAM6_SKYLAKE_X)) &&
+ (m->bank == 0) &&
+ ((m->status & 0xa0000000ffffffff) == 0x80000000000f0005))
+ return true;
+
+ return false;
+}