Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

13 files changed, 7231 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/mce/Makefile b/arch/x86/kernel/cpu/mce/Makefile
new file mode 100644
index 0000000000..015856abdb
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/Makefile
@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-y				=  core.o severity.o genpool.o
+
+obj-$(CONFIG_X86_ANCIENT_MCE)	+= winchip.o p5.o
+obj-$(CONFIG_X86_MCE_INTEL)	+= intel.o
+obj-$(CONFIG_X86_MCE_AMD)	+= amd.o
+obj-$(CONFIG_X86_MCE_THRESHOLD) += threshold.o
+
+mce-inject-y			:= inject.o
+obj-$(CONFIG_X86_MCE_INJECT)	+= mce-inject.o
+
+obj-$(CONFIG_ACPI_APEI)		+= apei.o
+
+obj-$(CONFIG_X86_MCELOG_LEGACY)	+= dev-mcelog.o
diff --git a/arch/x86/kernel/cpu/mce/amd.c b/arch/x86/kernel/cpu/mce/amd.c
new file mode 100644
index 0000000000..c267f43de3
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/amd.c
@@ -0,0 +1,1374 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ *  (c) 2005-2016 Advanced Micro Devices, Inc.
+ *
+ *  Written by Jacob Shin - AMD, Inc.
+ *  Maintained by: Borislav Petkov <bp@alien8.de>
+ *
+ *  All MC4_MISCi registers are shared between cores on a node.
+ */
+#include <linux/interrupt.h>
+#include <linux/notifier.h>
+#include <linux/kobject.h>
+#include <linux/percpu.h>
+#include <linux/errno.h>
+#include <linux/sched.h>
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
+#include <linux/smp.h>
+#include <linux/string.h>
+
+#include <asm/amd_nb.h>
+#include <asm/traps.h>
+#include <asm/apic.h>
+#include <asm/mce.h>
+#include <asm/msr.h>
+#include <asm/trace/irq_vectors.h>
+
+#include "internal.h"
+
+#define NR_BLOCKS         5
+#define THRESHOLD_MAX     0xFFF
+#define INT_TYPE_APIC     0x00020000
+#define MASK_VALID_HI     0x80000000
+#define MASK_CNTP_HI      0x40000000
+#define MASK_LOCKED_HI    0x20000000
+#define MASK_LVTOFF_HI    0x00F00000
+#define MASK_COUNT_EN_HI  0x00080000
+#define MASK_INT_TYPE_HI  0x00060000
+#define MASK_OVERFLOW_HI  0x00010000
+#define MASK_ERR_COUNT_HI 0x00000FFF
+#define MASK_BLKPTR_LO    0xFF000000
+#define MCG_XBLK_ADDR     0xC0000400
+
+/* Deferred error settings */
+#define MSR_CU_DEF_ERR		0xC0000410
+#define MASK_DEF_LVTOFF		0x000000F0
+#define MASK_DEF_INT_TYPE	0x00000006
+#define DEF_LVT_OFF		0x2
+#define DEF_INT_TYPE_APIC	0x2
+
+/* Scalable MCA: */
+
+/* Threshold LVT offset is at MSR0xC0000410[15:12] */
+#define SMCA_THR_LVT_OFF	0xF000
+
+static bool thresholding_irq_en;
+
+static const char * const th_names[] = {
+	"load_store",
+	"insn_fetch",
+	"combined_unit",
+	"decode_unit",
+	"northbridge",
+	"execution_unit",
+};
+
+static const char * const smca_umc_block_names[] = {
+	"dram_ecc",
+	"misc_umc"
+};
+
+#define HWID_MCATYPE(hwid, mcatype) (((hwid) << 16) | (mcatype))
+
+struct smca_hwid {
+	unsigned int bank_type;	/* Use with smca_bank_types for easy indexing. */
+	u32 hwid_mcatype;	/* (hwid,mcatype) tuple */
+};
+
+struct smca_bank {
+	const struct smca_hwid *hwid;
+	u32 id;			/* Value of MCA_IPID[InstanceId]. */
+	u8 sysfs_id;		/* Value used for sysfs name. */
+};
+
+static DEFINE_PER_CPU_READ_MOSTLY(struct smca_bank[MAX_NR_BANKS], smca_banks);
+static DEFINE_PER_CPU_READ_MOSTLY(u8[N_SMCA_BANK_TYPES], smca_bank_counts);
+
+struct smca_bank_name {
+	const char *name;	/* Short name for sysfs */
+	const char *long_name;	/* Long name for pretty-printing */
+};
+
+static struct smca_bank_name smca_names[] = {
+	[SMCA_LS ... SMCA_LS_V2]	= { "load_store",	"Load Store Unit" },
+	[SMCA_IF]			= { "insn_fetch",	"Instruction Fetch Unit" },
+	[SMCA_L2_CACHE]			= { "l2_cache",		"L2 Cache" },
+	[SMCA_DE]			= { "decode_unit",	"Decode Unit" },
+	[SMCA_RESERVED]			= { "reserved",		"Reserved" },
+	[SMCA_EX]			= { "execution_unit",	"Execution Unit" },
+	[SMCA_FP]			= { "floating_point",	"Floating Point Unit" },
+	[SMCA_L3_CACHE]			= { "l3_cache",		"L3 Cache" },
+	[SMCA_CS ... SMCA_CS_V2]	= { "coherent_slave",	"Coherent Slave" },
+	[SMCA_PIE]			= { "pie",		"Power, Interrupts, etc." },
+
+	/* UMC v2 is separate because both of them can exist in a single system. */
+	[SMCA_UMC]			= { "umc",		"Unified Memory Controller" },
+	[SMCA_UMC_V2]			= { "umc_v2",		"Unified Memory Controller v2" },
+	[SMCA_PB]			= { "param_block",	"Parameter Block" },
+	[SMCA_PSP ... SMCA_PSP_V2]	= { "psp",		"Platform Security Processor" },
+	[SMCA_SMU ... SMCA_SMU_V2]	= { "smu",		"System Management Unit" },
+	[SMCA_MP5]			= { "mp5",		"Microprocessor 5 Unit" },
+	[SMCA_MPDMA]			= { "mpdma",		"MPDMA Unit" },
+	[SMCA_NBIO]			= { "nbio",		"Northbridge IO Unit" },
+	[SMCA_PCIE ... SMCA_PCIE_V2]	= { "pcie",		"PCI Express Unit" },
+	[SMCA_XGMI_PCS]			= { "xgmi_pcs",		"Ext Global Memory Interconnect PCS Unit" },
+	[SMCA_NBIF]			= { "nbif",		"NBIF Unit" },
+	[SMCA_SHUB]			= { "shub",		"System Hub Unit" },
+	[SMCA_SATA]			= { "sata",		"SATA Unit" },
+	[SMCA_USB]			= { "usb",		"USB Unit" },
+	[SMCA_GMI_PCS]			= { "gmi_pcs",		"Global Memory Interconnect PCS Unit" },
+	[SMCA_XGMI_PHY]			= { "xgmi_phy",		"Ext Global Memory Interconnect PHY Unit" },
+	[SMCA_WAFL_PHY]			= { "wafl_phy",		"WAFL PHY Unit" },
+	[SMCA_GMI_PHY]			= { "gmi_phy",		"Global Memory Interconnect PHY Unit" },
+};
+
+static const char *smca_get_name(enum smca_bank_types t)
+{
+	if (t >= N_SMCA_BANK_TYPES)
+		return NULL;
+
+	return smca_names[t].name;
+}
+
+const char *smca_get_long_name(enum smca_bank_types t)
+{
+	if (t >= N_SMCA_BANK_TYPES)
+		return NULL;
+
+	return smca_names[t].long_name;
+}
+EXPORT_SYMBOL_GPL(smca_get_long_name);
+
+enum smca_bank_types smca_get_bank_type(unsigned int cpu, unsigned int bank)
+{
+	struct smca_bank *b;
+
+	if (bank >= MAX_NR_BANKS)
+		return N_SMCA_BANK_TYPES;
+
+	b = &per_cpu(smca_banks, cpu)[bank];
+	if (!b->hwid)
+		return N_SMCA_BANK_TYPES;
+
+	return b->hwid->bank_type;
+}
+EXPORT_SYMBOL_GPL(smca_get_bank_type);
+
+static const struct smca_hwid smca_hwid_mcatypes[] = {
+	/* { bank_type, hwid_mcatype } */
+
+	/* Reserved type */
+	{ SMCA_RESERVED, HWID_MCATYPE(0x00, 0x0)	},
+
+	/* ZN Core (HWID=0xB0) MCA types */
+	{ SMCA_LS,	 HWID_MCATYPE(0xB0, 0x0)	},
+	{ SMCA_LS_V2,	 HWID_MCATYPE(0xB0, 0x10)	},
+	{ SMCA_IF,	 HWID_MCATYPE(0xB0, 0x1)	},
+	{ SMCA_L2_CACHE, HWID_MCATYPE(0xB0, 0x2)	},
+	{ SMCA_DE,	 HWID_MCATYPE(0xB0, 0x3)	},
+	/* HWID 0xB0 MCATYPE 0x4 is Reserved */
+	{ SMCA_EX,	 HWID_MCATYPE(0xB0, 0x5)	},
+	{ SMCA_FP,	 HWID_MCATYPE(0xB0, 0x6)	},
+	{ SMCA_L3_CACHE, HWID_MCATYPE(0xB0, 0x7)	},
+
+	/* Data Fabric MCA types */
+	{ SMCA_CS,	 HWID_MCATYPE(0x2E, 0x0)	},
+	{ SMCA_PIE,	 HWID_MCATYPE(0x2E, 0x1)	},
+	{ SMCA_CS_V2,	 HWID_MCATYPE(0x2E, 0x2)	},
+
+	/* Unified Memory Controller MCA type */
+	{ SMCA_UMC,	 HWID_MCATYPE(0x96, 0x0)	},
+	{ SMCA_UMC_V2,	 HWID_MCATYPE(0x96, 0x1)	},
+
+	/* Parameter Block MCA type */
+	{ SMCA_PB,	 HWID_MCATYPE(0x05, 0x0)	},
+
+	/* Platform Security Processor MCA type */
+	{ SMCA_PSP,	 HWID_MCATYPE(0xFF, 0x0)	},
+	{ SMCA_PSP_V2,	 HWID_MCATYPE(0xFF, 0x1)	},
+
+	/* System Management Unit MCA type */
+	{ SMCA_SMU,	 HWID_MCATYPE(0x01, 0x0)	},
+	{ SMCA_SMU_V2,	 HWID_MCATYPE(0x01, 0x1)	},
+
+	/* Microprocessor 5 Unit MCA type */
+	{ SMCA_MP5,	 HWID_MCATYPE(0x01, 0x2)	},
+
+	/* MPDMA MCA type */
+	{ SMCA_MPDMA,	 HWID_MCATYPE(0x01, 0x3)	},
+
+	/* Northbridge IO Unit MCA type */
+	{ SMCA_NBIO,	 HWID_MCATYPE(0x18, 0x0)	},
+
+	/* PCI Express Unit MCA type */
+	{ SMCA_PCIE,	 HWID_MCATYPE(0x46, 0x0)	},
+	{ SMCA_PCIE_V2,	 HWID_MCATYPE(0x46, 0x1)	},
+
+	{ SMCA_XGMI_PCS, HWID_MCATYPE(0x50, 0x0)	},
+	{ SMCA_NBIF,	 HWID_MCATYPE(0x6C, 0x0)	},
+	{ SMCA_SHUB,	 HWID_MCATYPE(0x80, 0x0)	},
+	{ SMCA_SATA,	 HWID_MCATYPE(0xA8, 0x0)	},
+	{ SMCA_USB,	 HWID_MCATYPE(0xAA, 0x0)	},
+	{ SMCA_GMI_PCS,  HWID_MCATYPE(0x241, 0x0)	},
+	{ SMCA_XGMI_PHY, HWID_MCATYPE(0x259, 0x0)	},
+	{ SMCA_WAFL_PHY, HWID_MCATYPE(0x267, 0x0)	},
+	{ SMCA_GMI_PHY,	 HWID_MCATYPE(0x269, 0x0)	},
+};
+
+/*
+ * In SMCA enabled processors, we can have multiple banks for a given IP type.
+ * So to define a unique name for each bank, we use a temp c-string to append
+ * the MCA_IPID[InstanceId] to type's name in get_name().
+ *
+ * InstanceId is 32 bits which is 8 characters. Make sure MAX_MCATYPE_NAME_LEN
+ * is greater than 8 plus 1 (for underscore) plus length of longest type name.
+ */
+#define MAX_MCATYPE_NAME_LEN	30
+static char buf_mcatype[MAX_MCATYPE_NAME_LEN];
+
+static DEFINE_PER_CPU(struct threshold_bank **, threshold_banks);
+
+/*
+ * A list of the banks enabled on each logical CPU. Controls which respective
+ * descriptors to initialize later in mce_threshold_create_device().
+ */
+static DEFINE_PER_CPU(u64, bank_map);
+
+/* Map of banks that have more than MCA_MISC0 available. */
+static DEFINE_PER_CPU(u64, smca_misc_banks_map);
+
+static void amd_threshold_interrupt(void);
+static void amd_deferred_error_interrupt(void);
+
+static void default_deferred_error_interrupt(void)
+{
+	pr_err("Unexpected deferred interrupt at vector %x\n", DEFERRED_ERROR_VECTOR);
+}
+void (*deferred_error_int_vector)(void) = default_deferred_error_interrupt;
+
+static void smca_set_misc_banks_map(unsigned int bank, unsigned int cpu)
+{
+	u32 low, high;
+
+	/*
+	 * For SMCA enabled processors, BLKPTR field of the first MISC register
+	 * (MCx_MISC0) indicates presence of additional MISC regs set (MISC1-4).
+	 */
+	if (rdmsr_safe(MSR_AMD64_SMCA_MCx_CONFIG(bank), &low, &high))
+		return;
+
+	if (!(low & MCI_CONFIG_MCAX))
+		return;
+
+	if (rdmsr_safe(MSR_AMD64_SMCA_MCx_MISC(bank), &low, &high))
+		return;
+
+	if (low & MASK_BLKPTR_LO)
+		per_cpu(smca_misc_banks_map, cpu) |= BIT_ULL(bank);
+
+}
+
+static void smca_configure(unsigned int bank, unsigned int cpu)
+{
+	u8 *bank_counts = this_cpu_ptr(smca_bank_counts);
+	const struct smca_hwid *s_hwid;
+	unsigned int i, hwid_mcatype;
+	u32 high, low;
+	u32 smca_config = MSR_AMD64_SMCA_MCx_CONFIG(bank);
+
+	/* Set appropriate bits in MCA_CONFIG */
+	if (!rdmsr_safe(smca_config, &low, &high)) {
+		/*
+		 * OS is required to set the MCAX bit to acknowledge that it is
+		 * now using the new MSR ranges and new registers under each
+		 * bank. It also means that the OS will configure deferred
+		 * errors in the new MCx_CONFIG register. If the bit is not set,
+		 * uncorrectable errors will cause a system panic.
+		 *
+		 * MCA_CONFIG[MCAX] is bit 32 (0 in the high portion of the MSR.)
+		 */
+		high |= BIT(0);
+
+		/*
+		 * SMCA sets the Deferred Error Interrupt type per bank.
+		 *
+		 * MCA_CONFIG[DeferredIntTypeSupported] is bit 5, and tells us
+		 * if the DeferredIntType bit field is available.
+		 *
+		 * MCA_CONFIG[DeferredIntType] is bits [38:37] ([6:5] in the
+		 * high portion of the MSR). OS should set this to 0x1 to enable
+		 * APIC based interrupt. First, check that no interrupt has been
+		 * set.
+		 */
+		if ((low & BIT(5)) && !((high >> 5) & 0x3))
+			high |= BIT(5);
+
+		this_cpu_ptr(mce_banks_array)[bank].lsb_in_status = !!(low & BIT(8));
+
+		wrmsr(smca_config, low, high);
+	}
+
+	smca_set_misc_banks_map(bank, cpu);
+
+	if (rdmsr_safe(MSR_AMD64_SMCA_MCx_IPID(bank), &low, &high)) {
+		pr_warn("Failed to read MCA_IPID for bank %d\n", bank);
+		return;
+	}
+
+	hwid_mcatype = HWID_MCATYPE(high & MCI_IPID_HWID,
+				    (high & MCI_IPID_MCATYPE) >> 16);
+
+	for (i = 0; i < ARRAY_SIZE(smca_hwid_mcatypes); i++) {
+		s_hwid = &smca_hwid_mcatypes[i];
+
+		if (hwid_mcatype == s_hwid->hwid_mcatype) {
+			this_cpu_ptr(smca_banks)[bank].hwid = s_hwid;
+			this_cpu_ptr(smca_banks)[bank].id = low;
+			this_cpu_ptr(smca_banks)[bank].sysfs_id = bank_counts[s_hwid->bank_type]++;
+			break;
+		}
+	}
+}
+
+struct thresh_restart {
+	struct threshold_block	*b;
+	int			reset;
+	int			set_lvt_off;
+	int			lvt_off;
+	u16			old_limit;
+};
+
+static inline bool is_shared_bank(int bank)
+{
+	/*
+	 * Scalable MCA provides for only one core to have access to the MSRs of
+	 * a shared bank.
+	 */
+	if (mce_flags.smca)
+		return false;
+
+	/* Bank 4 is for northbridge reporting and is thus shared */
+	return (bank == 4);
+}
+
+static const char *bank4_names(const struct threshold_block *b)
+{
+	switch (b->address) {
+	/* MSR4_MISC0 */
+	case 0x00000413:
+		return "dram";
+
+	case 0xc0000408:
+		return "ht_links";
+
+	case 0xc0000409:
+		return "l3_cache";
+
+	default:
+		WARN(1, "Funny MSR: 0x%08x\n", b->address);
+		return "";
+	}
+};
+
+
+static bool lvt_interrupt_supported(unsigned int bank, u32 msr_high_bits)
+{
+	/*
+	 * bank 4 supports APIC LVT interrupts implicitly since forever.
+	 */
+	if (bank == 4)
+		return true;
+
+	/*
+	 * IntP: interrupt present; if this bit is set, the thresholding
+	 * bank can generate APIC LVT interrupts
+	 */
+	return msr_high_bits & BIT(28);
+}
+
+static int lvt_off_valid(struct threshold_block *b, int apic, u32 lo, u32 hi)
+{
+	int msr = (hi & MASK_LVTOFF_HI) >> 20;
+
+	if (apic < 0) {
+		pr_err(FW_BUG "cpu %d, failed to setup threshold interrupt "
+		       "for bank %d, block %d (MSR%08X=0x%x%08x)\n", b->cpu,
+		       b->bank, b->block, b->address, hi, lo);
+		return 0;
+	}
+
+	if (apic != msr) {
+		/*
+		 * On SMCA CPUs, LVT offset is programmed at a different MSR, and
+		 * the BIOS provides the value. The original field where LVT offset
+		 * was set is reserved. Return early here:
+		 */
+		if (mce_flags.smca)
+			return 0;
+
+		pr_err(FW_BUG "cpu %d, invalid threshold interrupt offset %d "
+		       "for bank %d, block %d (MSR%08X=0x%x%08x)\n",
+		       b->cpu, apic, b->bank, b->block, b->address, hi, lo);
+		return 0;
+	}
+
+	return 1;
+};
+
+/* Reprogram MCx_MISC MSR behind this threshold bank. */
+static void threshold_restart_bank(void *_tr)
+{
+	struct thresh_restart *tr = _tr;
+	u32 hi, lo;
+
+	/* sysfs write might race against an offline operation */
+	if (!this_cpu_read(threshold_banks) && !tr->set_lvt_off)
+		return;
+
+	rdmsr(tr->b->address, lo, hi);
+
+	if (tr->b->threshold_limit < (hi & THRESHOLD_MAX))
+		tr->reset = 1;	/* limit cannot be lower than err count */
+
+	if (tr->reset) {		/* reset err count and overflow bit */
+		hi =
+		    (hi & ~(MASK_ERR_COUNT_HI | MASK_OVERFLOW_HI)) |
+		    (THRESHOLD_MAX - tr->b->threshold_limit);
+	} else if (tr->old_limit) {	/* change limit w/o reset */
+		int new_count = (hi & THRESHOLD_MAX) +
+		    (tr->old_limit - tr->b->threshold_limit);
+
+		hi = (hi & ~MASK_ERR_COUNT_HI) |
+		    (new_count & THRESHOLD_MAX);
+	}
+
+	/* clear IntType */
+	hi &= ~MASK_INT_TYPE_HI;
+
+	if (!tr->b->interrupt_capable)
+		goto done;
+
+	if (tr->set_lvt_off) {
+		if (lvt_off_valid(tr->b, tr->lvt_off, lo, hi)) {
+			/* set new lvt offset */
+			hi &= ~MASK_LVTOFF_HI;
+			hi |= tr->lvt_off << 20;
+		}
+	}
+
+	if (tr->b->interrupt_enable)
+		hi |= INT_TYPE_APIC;
+
+ done:
+
+	hi |= MASK_COUNT_EN_HI;
+	wrmsr(tr->b->address, lo, hi);
+}
+
+static void mce_threshold_block_init(struct threshold_block *b, int offset)
+{
+	struct thresh_restart tr = {
+		.b			= b,
+		.set_lvt_off		= 1,
+		.lvt_off		= offset,
+	};
+
+	b->threshold_limit		= THRESHOLD_MAX;
+	threshold_restart_bank(&tr);
+};
+
+static int setup_APIC_mce_threshold(int reserved, int new)
+{
+	if (reserved < 0 && !setup_APIC_eilvt(new, THRESHOLD_APIC_VECTOR,
+					      APIC_EILVT_MSG_FIX, 0))
+		return new;
+
+	return reserved;
+}
+
+static int setup_APIC_deferred_error(int reserved, int new)
+{
+	if (reserved < 0 && !setup_APIC_eilvt(new, DEFERRED_ERROR_VECTOR,
+					      APIC_EILVT_MSG_FIX, 0))
+		return new;
+
+	return reserved;
+}
+
+static void deferred_error_interrupt_enable(struct cpuinfo_x86 *c)
+{
+	u32 low = 0, high = 0;
+	int def_offset = -1, def_new;
+
+	if (rdmsr_safe(MSR_CU_DEF_ERR, &low, &high))
+		return;
+
+	def_new = (low & MASK_DEF_LVTOFF) >> 4;
+	if (!(low & MASK_DEF_LVTOFF)) {
+		pr_err(FW_BUG "Your BIOS is not setting up LVT offset 0x2 for deferred error IRQs correctly.\n");
+		def_new = DEF_LVT_OFF;
+		low = (low & ~MASK_DEF_LVTOFF) | (DEF_LVT_OFF << 4);
+	}
+
+	def_offset = setup_APIC_deferred_error(def_offset, def_new);
+	if ((def_offset == def_new) &&
+	    (deferred_error_int_vector != amd_deferred_error_interrupt))
+		deferred_error_int_vector = amd_deferred_error_interrupt;
+
+	if (!mce_flags.smca)
+		low = (low & ~MASK_DEF_INT_TYPE) | DEF_INT_TYPE_APIC;
+
+	wrmsr(MSR_CU_DEF_ERR, low, high);
+}
+
+static u32 smca_get_block_address(unsigned int bank, unsigned int block,
+				  unsigned int cpu)
+{
+	if (!block)
+		return MSR_AMD64_SMCA_MCx_MISC(bank);
+
+	if (!(per_cpu(smca_misc_banks_map, cpu) & BIT_ULL(bank)))
+		return 0;
+
+	return MSR_AMD64_SMCA_MCx_MISCy(bank, block - 1);
+}
+
+static u32 get_block_address(u32 current_addr, u32 low, u32 high,
+			     unsigned int bank, unsigned int block,
+			     unsigned int cpu)
+{
+	u32 addr = 0, offset = 0;
+
+	if ((bank >= per_cpu(mce_num_banks, cpu)) || (block >= NR_BLOCKS))
+		return addr;
+
+	if (mce_flags.smca)
+		return smca_get_block_address(bank, block, cpu);
+
+	/* Fall back to method we used for older processors: */
+	switch (block) {
+	case 0:
+		addr = mca_msr_reg(bank, MCA_MISC);
+		break;
+	case 1:
+		offset = ((low & MASK_BLKPTR_LO) >> 21);
+		if (offset)
+			addr = MCG_XBLK_ADDR + offset;
+		break;
+	default:
+		addr = ++current_addr;
+	}
+	return addr;
+}
+
+static int
+prepare_threshold_block(unsigned int bank, unsigned int block, u32 addr,
+			int offset, u32 misc_high)
+{
+	unsigned int cpu = smp_processor_id();
+	u32 smca_low, smca_high;
+	struct threshold_block b;
+	int new;
+
+	if (!block)
+		per_cpu(bank_map, cpu) |= BIT_ULL(bank);
+
+	memset(&b, 0, sizeof(b));
+	b.cpu			= cpu;
+	b.bank			= bank;
+	b.block			= block;
+	b.address		= addr;
+	b.interrupt_capable	= lvt_interrupt_supported(bank, misc_high);
+
+	if (!b.interrupt_capable)
+		goto done;
+
+	b.interrupt_enable = 1;
+
+	if (!mce_flags.smca) {
+		new = (misc_high & MASK_LVTOFF_HI) >> 20;
+		goto set_offset;
+	}
+
+	/* Gather LVT offset for thresholding: */
+	if (rdmsr_safe(MSR_CU_DEF_ERR, &smca_low, &smca_high))
+		goto out;
+
+	new = (smca_low & SMCA_THR_LVT_OFF) >> 12;
+
+set_offset:
+	offset = setup_APIC_mce_threshold(offset, new);
+	if (offset == new)
+		thresholding_irq_en = true;
+
+done:
+	mce_threshold_block_init(&b, offset);
+
+out:
+	return offset;
+}
+
+bool amd_filter_mce(struct mce *m)
+{
+	enum smca_bank_types bank_type = smca_get_bank_type(m->extcpu, m->bank);
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	/* See Family 17h Models 10h-2Fh Erratum #1114. */
+	if (c->x86 == 0x17 &&
+	    c->x86_model >= 0x10 && c->x86_model <= 0x2F &&
+	    bank_type == SMCA_IF && XEC(m->status, 0x3f) == 10)
+		return true;
+
+	/* NB GART TLB error reporting is disabled by default. */
+	if (c->x86 < 0x17) {
+		if (m->bank == 4 && XEC(m->status, 0x1f) == 0x5)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Turn off thresholding banks for the following conditions:
+ * - MC4_MISC thresholding is not supported on Family 0x15.
+ * - Prevent possible spurious interrupts from the IF bank on Family 0x17
+ *   Models 0x10-0x2F due to Erratum #1114.
+ */
+static void disable_err_thresholding(struct cpuinfo_x86 *c, unsigned int bank)
+{
+	int i, num_msrs;
+	u64 hwcr;
+	bool need_toggle;
+	u32 msrs[NR_BLOCKS];
+
+	if (c->x86 == 0x15 && bank == 4) {
+		msrs[0] = 0x00000413; /* MC4_MISC0 */
+		msrs[1] = 0xc0000408; /* MC4_MISC1 */
+		num_msrs = 2;
+	} else if (c->x86 == 0x17 &&
+		   (c->x86_model >= 0x10 && c->x86_model <= 0x2F)) {
+
+		if (smca_get_bank_type(smp_processor_id(), bank) != SMCA_IF)
+			return;
+
+		msrs[0] = MSR_AMD64_SMCA_MCx_MISC(bank);
+		num_msrs = 1;
+	} else {
+		return;
+	}
+
+	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 < num_msrs; i++)
+		msr_clear_bit(msrs[i], 62);
+
+	/* restore old settings */
+	if (need_toggle)
+		wrmsrl(MSR_K7_HWCR, hwcr);
+}
+
+/* cpu init entry point, called from mce.c with preempt off */
+void mce_amd_feature_init(struct cpuinfo_x86 *c)
+{
+	unsigned int bank, block, cpu = smp_processor_id();
+	u32 low = 0, high = 0, address = 0;
+	int offset = -1;
+
+
+	for (bank = 0; bank < this_cpu_read(mce_num_banks); ++bank) {
+		if (mce_flags.smca)
+			smca_configure(bank, cpu);
+
+		disable_err_thresholding(c, bank);
+
+		for (block = 0; block < NR_BLOCKS; ++block) {
+			address = get_block_address(address, low, high, bank, block, cpu);
+			if (!address)
+				break;
+
+			if (rdmsr_safe(address, &low, &high))
+				break;
+
+			if (!(high & MASK_VALID_HI))
+				continue;
+
+			if (!(high & MASK_CNTP_HI)  ||
+			     (high & MASK_LOCKED_HI))
+				continue;
+
+			offset = prepare_threshold_block(bank, block, address, offset, high);
+		}
+	}
+
+	if (mce_flags.succor)
+		deferred_error_interrupt_enable(c);
+}
+
+bool amd_mce_is_memory_error(struct mce *m)
+{
+	enum smca_bank_types bank_type;
+	/* ErrCodeExt[20:16] */
+	u8 xec = (m->status >> 16) & 0x1f;
+
+	bank_type = smca_get_bank_type(m->extcpu, m->bank);
+	if (mce_flags.smca)
+		return (bank_type == SMCA_UMC || bank_type == SMCA_UMC_V2) && xec == 0x0;
+
+	return m->bank == 4 && xec == 0x8;
+}
+
+static void __log_error(unsigned int bank, u64 status, u64 addr, u64 misc)
+{
+	struct mce m;
+
+	mce_setup(&m);
+
+	m.status = status;
+	m.misc   = misc;
+	m.bank   = bank;
+	m.tsc	 = rdtsc();
+
+	if (m.status & MCI_STATUS_ADDRV) {
+		m.addr = addr;
+
+		smca_extract_err_addr(&m);
+	}
+
+	if (mce_flags.smca) {
+		rdmsrl(MSR_AMD64_SMCA_MCx_IPID(bank), m.ipid);
+
+		if (m.status & MCI_STATUS_SYNDV)
+			rdmsrl(MSR_AMD64_SMCA_MCx_SYND(bank), m.synd);
+	}
+
+	mce_log(&m);
+}
+
+DEFINE_IDTENTRY_SYSVEC(sysvec_deferred_error)
+{
+	trace_deferred_error_apic_entry(DEFERRED_ERROR_VECTOR);
+	inc_irq_stat(irq_deferred_error_count);
+	deferred_error_int_vector();
+	trace_deferred_error_apic_exit(DEFERRED_ERROR_VECTOR);
+	apic_eoi();
+}
+
+/*
+ * Returns true if the logged error is deferred. False, otherwise.
+ */
+static inline bool
+_log_error_bank(unsigned int bank, u32 msr_stat, u32 msr_addr, u64 misc)
+{
+	u64 status, addr = 0;
+
+	rdmsrl(msr_stat, status);
+	if (!(status & MCI_STATUS_VAL))
+		return false;
+
+	if (status & MCI_STATUS_ADDRV)
+		rdmsrl(msr_addr, addr);
+
+	__log_error(bank, status, addr, misc);
+
+	wrmsrl(msr_stat, 0);
+
+	return status & MCI_STATUS_DEFERRED;
+}
+
+static bool _log_error_deferred(unsigned int bank, u32 misc)
+{
+	if (!_log_error_bank(bank, mca_msr_reg(bank, MCA_STATUS),
+			     mca_msr_reg(bank, MCA_ADDR), misc))
+		return false;
+
+	/*
+	 * Non-SMCA systems don't have MCA_DESTAT/MCA_DEADDR registers.
+	 * Return true here to avoid accessing these registers.
+	 */
+	if (!mce_flags.smca)
+		return true;
+
+	/* Clear MCA_DESTAT if the deferred error was logged from MCA_STATUS. */
+	wrmsrl(MSR_AMD64_SMCA_MCx_DESTAT(bank), 0);
+	return true;
+}
+
+/*
+ * We have three scenarios for checking for Deferred errors:
+ *
+ * 1) Non-SMCA systems check MCA_STATUS and log error if found.
+ * 2) SMCA systems check MCA_STATUS. If error is found then log it and also
+ *    clear MCA_DESTAT.
+ * 3) SMCA systems check MCA_DESTAT, if error was not found in MCA_STATUS, and
+ *    log it.
+ */
+static void log_error_deferred(unsigned int bank)
+{
+	if (_log_error_deferred(bank, 0))
+		return;
+
+	/*
+	 * Only deferred errors are logged in MCA_DE{STAT,ADDR} so just check
+	 * for a valid error.
+	 */
+	_log_error_bank(bank, MSR_AMD64_SMCA_MCx_DESTAT(bank),
+			      MSR_AMD64_SMCA_MCx_DEADDR(bank), 0);
+}
+
+/* APIC interrupt handler for deferred errors */
+static void amd_deferred_error_interrupt(void)
+{
+	unsigned int bank;
+
+	for (bank = 0; bank < this_cpu_read(mce_num_banks); ++bank)
+		log_error_deferred(bank);
+}
+
+static void log_error_thresholding(unsigned int bank, u64 misc)
+{
+	_log_error_deferred(bank, misc);
+}
+
+static void log_and_reset_block(struct threshold_block *block)
+{
+	struct thresh_restart tr;
+	u32 low = 0, high = 0;
+
+	if (!block)
+		return;
+
+	if (rdmsr_safe(block->address, &low, &high))
+		return;
+
+	if (!(high & MASK_OVERFLOW_HI))
+		return;
+
+	/* Log the MCE which caused the threshold event. */
+	log_error_thresholding(block->bank, ((u64)high << 32) | low);
+
+	/* Reset threshold block after logging error. */
+	memset(&tr, 0, sizeof(tr));
+	tr.b = block;
+	threshold_restart_bank(&tr);
+}
+
+/*
+ * Threshold interrupt handler will service THRESHOLD_APIC_VECTOR. The interrupt
+ * goes off when error_count reaches threshold_limit.
+ */
+static void amd_threshold_interrupt(void)
+{
+	struct threshold_block *first_block = NULL, *block = NULL, *tmp = NULL;
+	struct threshold_bank **bp = this_cpu_read(threshold_banks);
+	unsigned int bank, cpu = smp_processor_id();
+
+	/*
+	 * Validate that the threshold bank has been initialized already. The
+	 * handler is installed at boot time, but on a hotplug event the
+	 * interrupt might fire before the data has been initialized.
+	 */
+	if (!bp)
+		return;
+
+	for (bank = 0; bank < this_cpu_read(mce_num_banks); ++bank) {
+		if (!(per_cpu(bank_map, cpu) & BIT_ULL(bank)))
+			continue;
+
+		first_block = bp[bank]->blocks;
+		if (!first_block)
+			continue;
+
+		/*
+		 * The first block is also the head of the list. Check it first
+		 * before iterating over the rest.
+		 */
+		log_and_reset_block(first_block);
+		list_for_each_entry_safe(block, tmp, &first_block->miscj, miscj)
+			log_and_reset_block(block);
+	}
+}
+
+/*
+ * Sysfs Interface
+ */
+
+struct threshold_attr {
+	struct attribute attr;
+	ssize_t (*show) (struct threshold_block *, char *);
+	ssize_t (*store) (struct threshold_block *, const char *, size_t count);
+};
+
+#define SHOW_FIELDS(name)						\
+static ssize_t show_ ## name(struct threshold_block *b, char *buf)	\
+{									\
+	return sprintf(buf, "%lu\n", (unsigned long) b->name);		\
+}
+SHOW_FIELDS(interrupt_enable)
+SHOW_FIELDS(threshold_limit)
+
+static ssize_t
+store_interrupt_enable(struct threshold_block *b, const char *buf, size_t size)
+{
+	struct thresh_restart tr;
+	unsigned long new;
+
+	if (!b->interrupt_capable)
+		return -EINVAL;
+
+	if (kstrtoul(buf, 0, &new) < 0)
+		return -EINVAL;
+
+	b->interrupt_enable = !!new;
+
+	memset(&tr, 0, sizeof(tr));
+	tr.b		= b;
+
+	if (smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1))
+		return -ENODEV;
+
+	return size;
+}
+
+static ssize_t
+store_threshold_limit(struct threshold_block *b, const char *buf, size_t size)
+{
+	struct thresh_restart tr;
+	unsigned long new;
+
+	if (kstrtoul(buf, 0, &new) < 0)
+		return -EINVAL;
+
+	if (new > THRESHOLD_MAX)
+		new = THRESHOLD_MAX;
+	if (new < 1)
+		new = 1;
+
+	memset(&tr, 0, sizeof(tr));
+	tr.old_limit = b->threshold_limit;
+	b->threshold_limit = new;
+	tr.b = b;
+
+	if (smp_call_function_single(b->cpu, threshold_restart_bank, &tr, 1))
+		return -ENODEV;
+
+	return size;
+}
+
+static ssize_t show_error_count(struct threshold_block *b, char *buf)
+{
+	u32 lo, hi;
+
+	/* CPU might be offline by now */
+	if (rdmsr_on_cpu(b->cpu, b->address, &lo, &hi))
+		return -ENODEV;
+
+	return sprintf(buf, "%u\n", ((hi & THRESHOLD_MAX) -
+				     (THRESHOLD_MAX - b->threshold_limit)));
+}
+
+static struct threshold_attr error_count = {
+	.attr = {.name = __stringify(error_count), .mode = 0444 },
+	.show = show_error_count,
+};
+
+#define RW_ATTR(val)							\
+static struct threshold_attr val = {					\
+	.attr	= {.name = __stringify(val), .mode = 0644 },		\
+	.show	= show_## val,						\
+	.store	= store_## val,						\
+};
+
+RW_ATTR(interrupt_enable);
+RW_ATTR(threshold_limit);
+
+static struct attribute *default_attrs[] = {
+	&threshold_limit.attr,
+	&error_count.attr,
+	NULL,	/* possibly interrupt_enable if supported, see below */
+	NULL,
+};
+ATTRIBUTE_GROUPS(default);
+
+#define to_block(k)	container_of(k, struct threshold_block, kobj)
+#define to_attr(a)	container_of(a, struct threshold_attr, attr)
+
+static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf)
+{
+	struct threshold_block *b = to_block(kobj);
+	struct threshold_attr *a = to_attr(attr);
+	ssize_t ret;
+
+	ret = a->show ? a->show(b, buf) : -EIO;
+
+	return ret;
+}
+
+static ssize_t store(struct kobject *kobj, struct attribute *attr,
+		     const char *buf, size_t count)
+{
+	struct threshold_block *b = to_block(kobj);
+	struct threshold_attr *a = to_attr(attr);
+	ssize_t ret;
+
+	ret = a->store ? a->store(b, buf, count) : -EIO;
+
+	return ret;
+}
+
+static const struct sysfs_ops threshold_ops = {
+	.show			= show,
+	.store			= store,
+};
+
+static void threshold_block_release(struct kobject *kobj);
+
+static const struct kobj_type threshold_ktype = {
+	.sysfs_ops		= &threshold_ops,
+	.default_groups		= default_groups,
+	.release		= threshold_block_release,
+};
+
+static const char *get_name(unsigned int cpu, unsigned int bank, struct threshold_block *b)
+{
+	enum smca_bank_types bank_type;
+
+	if (!mce_flags.smca) {
+		if (b && bank == 4)
+			return bank4_names(b);
+
+		return th_names[bank];
+	}
+
+	bank_type = smca_get_bank_type(cpu, bank);
+	if (bank_type >= N_SMCA_BANK_TYPES)
+		return NULL;
+
+	if (b && (bank_type == SMCA_UMC || bank_type == SMCA_UMC_V2)) {
+		if (b->block < ARRAY_SIZE(smca_umc_block_names))
+			return smca_umc_block_names[b->block];
+		return NULL;
+	}
+
+	if (per_cpu(smca_bank_counts, cpu)[bank_type] == 1)
+		return smca_get_name(bank_type);
+
+	snprintf(buf_mcatype, MAX_MCATYPE_NAME_LEN,
+		 "%s_%u", smca_get_name(bank_type),
+			  per_cpu(smca_banks, cpu)[bank].sysfs_id);
+	return buf_mcatype;
+}
+
+static int allocate_threshold_blocks(unsigned int cpu, struct threshold_bank *tb,
+				     unsigned int bank, unsigned int block,
+				     u32 address)
+{
+	struct threshold_block *b = NULL;
+	u32 low, high;
+	int err;
+
+	if ((bank >= this_cpu_read(mce_num_banks)) || (block >= NR_BLOCKS))
+		return 0;
+
+	if (rdmsr_safe(address, &low, &high))
+		return 0;
+
+	if (!(high & MASK_VALID_HI)) {
+		if (block)
+			goto recurse;
+		else
+			return 0;
+	}
+
+	if (!(high & MASK_CNTP_HI)  ||
+	     (high & MASK_LOCKED_HI))
+		goto recurse;
+
+	b = kzalloc(sizeof(struct threshold_block), GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
+
+	b->block		= block;
+	b->bank			= bank;
+	b->cpu			= cpu;
+	b->address		= address;
+	b->interrupt_enable	= 0;
+	b->interrupt_capable	= lvt_interrupt_supported(bank, high);
+	b->threshold_limit	= THRESHOLD_MAX;
+
+	if (b->interrupt_capable) {
+		default_attrs[2] = &interrupt_enable.attr;
+		b->interrupt_enable = 1;
+	} else {
+		default_attrs[2] = NULL;
+	}
+
+	INIT_LIST_HEAD(&b->miscj);
+
+	/* This is safe as @tb is not visible yet */
+	if (tb->blocks)
+		list_add(&b->miscj, &tb->blocks->miscj);
+	else
+		tb->blocks = b;
+
+	err = kobject_init_and_add(&b->kobj, &threshold_ktype, tb->kobj, get_name(cpu, bank, b));
+	if (err)
+		goto out_free;
+recurse:
+	address = get_block_address(address, low, high, bank, ++block, cpu);
+	if (!address)
+		return 0;
+
+	err = allocate_threshold_blocks(cpu, tb, bank, block, address);
+	if (err)
+		goto out_free;
+
+	if (b)
+		kobject_uevent(&b->kobj, KOBJ_ADD);
+
+	return 0;
+
+out_free:
+	if (b) {
+		list_del(&b->miscj);
+		kobject_put(&b->kobj);
+	}
+	return err;
+}
+
+static int __threshold_add_blocks(struct threshold_bank *b)
+{
+	struct list_head *head = &b->blocks->miscj;
+	struct threshold_block *pos = NULL;
+	struct threshold_block *tmp = NULL;
+	int err = 0;
+
+	err = kobject_add(&b->blocks->kobj, b->kobj, b->blocks->kobj.name);
+	if (err)
+		return err;
+
+	list_for_each_entry_safe(pos, tmp, head, miscj) {
+
+		err = kobject_add(&pos->kobj, b->kobj, pos->kobj.name);
+		if (err) {
+			list_for_each_entry_safe_reverse(pos, tmp, head, miscj)
+				kobject_del(&pos->kobj);
+
+			return err;
+		}
+	}
+	return err;
+}
+
+static int threshold_create_bank(struct threshold_bank **bp, unsigned int cpu,
+				 unsigned int bank)
+{
+	struct device *dev = this_cpu_read(mce_device);
+	struct amd_northbridge *nb = NULL;
+	struct threshold_bank *b = NULL;
+	const char *name = get_name(cpu, bank, NULL);
+	int err = 0;
+
+	if (!dev)
+		return -ENODEV;
+
+	if (is_shared_bank(bank)) {
+		nb = node_to_amd_nb(topology_die_id(cpu));
+
+		/* threshold descriptor already initialized on this node? */
+		if (nb && nb->bank4) {
+			/* yes, use it */
+			b = nb->bank4;
+			err = kobject_add(b->kobj, &dev->kobj, name);
+			if (err)
+				goto out;
+
+			bp[bank] = b;
+			refcount_inc(&b->cpus);
+
+			err = __threshold_add_blocks(b);
+
+			goto out;
+		}
+	}
+
+	b = kzalloc(sizeof(struct threshold_bank), GFP_KERNEL);
+	if (!b) {
+		err = -ENOMEM;
+		goto out;
+	}
+
+	/* Associate the bank with the per-CPU MCE device */
+	b->kobj = kobject_create_and_add(name, &dev->kobj);
+	if (!b->kobj) {
+		err = -EINVAL;
+		goto out_free;
+	}
+
+	if (is_shared_bank(bank)) {
+		b->shared = 1;
+		refcount_set(&b->cpus, 1);
+
+		/* nb is already initialized, see above */
+		if (nb) {
+			WARN_ON(nb->bank4);
+			nb->bank4 = b;
+		}
+	}
+
+	err = allocate_threshold_blocks(cpu, b, bank, 0, mca_msr_reg(bank, MCA_MISC));
+	if (err)
+		goto out_kobj;
+
+	bp[bank] = b;
+	return 0;
+
+out_kobj:
+	kobject_put(b->kobj);
+out_free:
+	kfree(b);
+out:
+	return err;
+}
+
+static void threshold_block_release(struct kobject *kobj)
+{
+	kfree(to_block(kobj));
+}
+
+static void deallocate_threshold_blocks(struct threshold_bank *bank)
+{
+	struct threshold_block *pos, *tmp;
+
+	list_for_each_entry_safe(pos, tmp, &bank->blocks->miscj, miscj) {
+		list_del(&pos->miscj);
+		kobject_put(&pos->kobj);
+	}
+
+	kobject_put(&bank->blocks->kobj);
+}
+
+static void __threshold_remove_blocks(struct threshold_bank *b)
+{
+	struct threshold_block *pos = NULL;
+	struct threshold_block *tmp = NULL;
+
+	kobject_put(b->kobj);
+
+	list_for_each_entry_safe(pos, tmp, &b->blocks->miscj, miscj)
+		kobject_put(b->kobj);
+}
+
+static void threshold_remove_bank(struct threshold_bank *bank)
+{
+	struct amd_northbridge *nb;
+
+	if (!bank->blocks)
+		goto out_free;
+
+	if (!bank->shared)
+		goto out_dealloc;
+
+	if (!refcount_dec_and_test(&bank->cpus)) {
+		__threshold_remove_blocks(bank);
+		return;
+	} else {
+		/*
+		 * The last CPU on this node using the shared bank is going
+		 * away, remove that bank now.
+		 */
+		nb = node_to_amd_nb(topology_die_id(smp_processor_id()));
+		nb->bank4 = NULL;
+	}
+
+out_dealloc:
+	deallocate_threshold_blocks(bank);
+
+out_free:
+	kobject_put(bank->kobj);
+	kfree(bank);
+}
+
+static void __threshold_remove_device(struct threshold_bank **bp)
+{
+	unsigned int bank, numbanks = this_cpu_read(mce_num_banks);
+
+	for (bank = 0; bank < numbanks; bank++) {
+		if (!bp[bank])
+			continue;
+
+		threshold_remove_bank(bp[bank]);
+		bp[bank] = NULL;
+	}
+	kfree(bp);
+}
+
+int mce_threshold_remove_device(unsigned int cpu)
+{
+	struct threshold_bank **bp = this_cpu_read(threshold_banks);
+
+	if (!bp)
+		return 0;
+
+	/*
+	 * Clear the pointer before cleaning up, so that the interrupt won't
+	 * touch anything of this.
+	 */
+	this_cpu_write(threshold_banks, NULL);
+
+	__threshold_remove_device(bp);
+	return 0;
+}
+
+/**
+ * mce_threshold_create_device - Create the per-CPU MCE threshold device
+ * @cpu:	The plugged in CPU
+ *
+ * Create directories and files for all valid threshold banks.
+ *
+ * This is invoked from the CPU hotplug callback which was installed in
+ * mcheck_init_device(). The invocation happens in context of the hotplug
+ * thread running on @cpu.  The callback is invoked on all CPUs which are
+ * online when the callback is installed or during a real hotplug event.
+ */
+int mce_threshold_create_device(unsigned int cpu)
+{
+	unsigned int numbanks, bank;
+	struct threshold_bank **bp;
+	int err;
+
+	if (!mce_flags.amd_threshold)
+		return 0;
+
+	bp = this_cpu_read(threshold_banks);
+	if (bp)
+		return 0;
+
+	numbanks = this_cpu_read(mce_num_banks);
+	bp = kcalloc(numbanks, sizeof(*bp), GFP_KERNEL);
+	if (!bp)
+		return -ENOMEM;
+
+	for (bank = 0; bank < numbanks; ++bank) {
+		if (!(this_cpu_read(bank_map) & BIT_ULL(bank)))
+			continue;
+		err = threshold_create_bank(bp, cpu, bank);
+		if (err) {
+			__threshold_remove_device(bp);
+			return err;
+		}
+	}
+	this_cpu_write(threshold_banks, bp);
+
+	if (thresholding_irq_en)
+		mce_threshold_vector = amd_threshold_interrupt;
+	return 0;
+}
diff --git a/arch/x86/kernel/cpu/mce/apei.c b/arch/x86/kernel/cpu/mce/apei.c
new file mode 100644
index 0000000000..8ed3417146
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/apei.c
@@ -0,0 +1,216 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Bridge between MCE and APEI
+ *
+ * On some machine, corrected memory errors are reported via APEI
+ * generic hardware error source (GHES) instead of corrected Machine
+ * Check. These corrected memory errors can be reported to user space
+ * through /dev/mcelog via faking a corrected Machine Check, so that
+ * the error memory page can be offlined by /sbin/mcelog if the error
+ * count for one page is beyond the threshold.
+ *
+ * For fatal MCE, save MCE record into persistent storage via ERST, so
+ * that the MCE record can be logged after reboot via ERST.
+ *
+ * Copyright 2010 Intel Corp.
+ *   Author: Huang Ying <ying.huang@intel.com>
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/cper.h>
+#include <acpi/apei.h>
+#include <acpi/ghes.h>
+#include <asm/mce.h>
+
+#include "internal.h"
+
+void apei_mce_report_mem_error(int severity, struct cper_sec_mem_err *mem_err)
+{
+	struct mce m;
+	int lsb;
+
+	if (!(mem_err->validation_bits & CPER_MEM_VALID_PA))
+		return;
+
+	/*
+	 * Even if the ->validation_bits are set for address mask,
+	 * to be extra safe, check and reject an error radius '0',
+	 * and fall back to the default page size.
+	 */
+	if (mem_err->validation_bits & CPER_MEM_VALID_PA_MASK)
+		lsb = find_first_bit((void *)&mem_err->physical_addr_mask, PAGE_SHIFT);
+	else
+		lsb = PAGE_SHIFT;
+
+	mce_setup(&m);
+	m.bank = -1;
+	/* Fake a memory read error with unknown channel */
+	m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | MCI_STATUS_MISCV | 0x9f;
+	m.misc = (MCI_MISC_ADDR_PHYS << 6) | lsb;
+
+	if (severity >= GHES_SEV_RECOVERABLE)
+		m.status |= MCI_STATUS_UC;
+
+	if (severity >= GHES_SEV_PANIC) {
+		m.status |= MCI_STATUS_PCC;
+		m.tsc = rdtsc();
+	}
+
+	m.addr = mem_err->physical_addr;
+	mce_log(&m);
+}
+EXPORT_SYMBOL_GPL(apei_mce_report_mem_error);
+
+int apei_smca_report_x86_error(struct cper_ia_proc_ctx *ctx_info, u64 lapic_id)
+{
+	const u64 *i_mce = ((const u64 *) (ctx_info + 1));
+	unsigned int cpu;
+	struct mce m;
+
+	if (!boot_cpu_has(X86_FEATURE_SMCA))
+		return -EINVAL;
+
+	/*
+	 * The starting address of the register array extracted from BERT must
+	 * match with the first expected register in the register layout of
+	 * SMCA address space. This address corresponds to banks's MCA_STATUS
+	 * register.
+	 *
+	 * Match any MCi_STATUS register by turning off bank numbers.
+	 */
+	if ((ctx_info->msr_addr & MSR_AMD64_SMCA_MC0_STATUS) !=
+				  MSR_AMD64_SMCA_MC0_STATUS)
+		return -EINVAL;
+
+	/*
+	 * The register array size must be large enough to include all the
+	 * SMCA registers which need to be extracted.
+	 *
+	 * The number of registers in the register array is determined by
+	 * Register Array Size/8 as defined in UEFI spec v2.8, sec N.2.4.2.2.
+	 * The register layout is fixed and currently the raw data in the
+	 * register array includes 6 SMCA registers which the kernel can
+	 * extract.
+	 */
+	if (ctx_info->reg_arr_size < 48)
+		return -EINVAL;
+
+	mce_setup(&m);
+
+	m.extcpu = -1;
+	m.socketid = -1;
+
+	for_each_possible_cpu(cpu) {
+		if (cpu_data(cpu).initial_apicid == lapic_id) {
+			m.extcpu = cpu;
+			m.socketid = cpu_data(m.extcpu).phys_proc_id;
+			break;
+		}
+	}
+
+	m.apicid = lapic_id;
+	m.bank = (ctx_info->msr_addr >> 4) & 0xFF;
+	m.status = *i_mce;
+	m.addr = *(i_mce + 1);
+	m.misc = *(i_mce + 2);
+	/* Skipping MCA_CONFIG */
+	m.ipid = *(i_mce + 4);
+	m.synd = *(i_mce + 5);
+
+	mce_log(&m);
+
+	return 0;
+}
+
+#define CPER_CREATOR_MCE						\
+	GUID_INIT(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,	\
+		  0x64, 0x90, 0xb8, 0x9d)
+#define CPER_SECTION_TYPE_MCE						\
+	GUID_INIT(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,	\
+		  0x04, 0x4a, 0x38, 0xfc)
+
+/*
+ * CPER specification (in UEFI specification 2.3 appendix N) requires
+ * byte-packed.
+ */
+struct cper_mce_record {
+	struct cper_record_header hdr;
+	struct cper_section_descriptor sec_hdr;
+	struct mce mce;
+} __packed;
+
+int apei_write_mce(struct mce *m)
+{
+	struct cper_mce_record rcd;
+
+	memset(&rcd, 0, sizeof(rcd));
+	memcpy(rcd.hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
+	rcd.hdr.revision = CPER_RECORD_REV;
+	rcd.hdr.signature_end = CPER_SIG_END;
+	rcd.hdr.section_count = 1;
+	rcd.hdr.error_severity = CPER_SEV_FATAL;
+	/* timestamp, platform_id, partition_id are all invalid */
+	rcd.hdr.validation_bits = 0;
+	rcd.hdr.record_length = sizeof(rcd);
+	rcd.hdr.creator_id = CPER_CREATOR_MCE;
+	rcd.hdr.notification_type = CPER_NOTIFY_MCE;
+	rcd.hdr.record_id = cper_next_record_id();
+	rcd.hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
+
+	rcd.sec_hdr.section_offset = (void *)&rcd.mce - (void *)&rcd;
+	rcd.sec_hdr.section_length = sizeof(rcd.mce);
+	rcd.sec_hdr.revision = CPER_SEC_REV;
+	/* fru_id and fru_text is invalid */
+	rcd.sec_hdr.validation_bits = 0;
+	rcd.sec_hdr.flags = CPER_SEC_PRIMARY;
+	rcd.sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
+	rcd.sec_hdr.section_severity = CPER_SEV_FATAL;
+
+	memcpy(&rcd.mce, m, sizeof(*m));
+
+	return erst_write(&rcd.hdr);
+}
+
+ssize_t apei_read_mce(struct mce *m, u64 *record_id)
+{
+	struct cper_mce_record rcd;
+	int rc, pos;
+
+	rc = erst_get_record_id_begin(&pos);
+	if (rc)
+		return rc;
+retry:
+	rc = erst_get_record_id_next(&pos, record_id);
+	if (rc)
+		goto out;
+	/* no more record */
+	if (*record_id == APEI_ERST_INVALID_RECORD_ID)
+		goto out;
+	rc = erst_read_record(*record_id, &rcd.hdr, sizeof(rcd), sizeof(rcd),
+			&CPER_CREATOR_MCE);
+	/* someone else has cleared the record, try next one */
+	if (rc == -ENOENT)
+		goto retry;
+	else if (rc < 0)
+		goto out;
+
+	memcpy(m, &rcd.mce, sizeof(*m));
+	rc = sizeof(*m);
+out:
+	erst_get_record_id_end();
+
+	return rc;
+}
+
+/* Check whether there is record in ERST */
+int apei_check_mce(void)
+{
+	return erst_get_record_count();
+}
+
+int apei_clear_mce(u64 record_id)
+{
+	return erst_clear(record_id);
+}
diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c
new file mode 100644
index 0000000000..6f35f724cc
--- /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, &current->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);
diff --git a/arch/x86/kernel/cpu/mce/dev-mcelog.c b/arch/x86/kernel/cpu/mce/dev-mcelog.c
new file mode 100644
index 0000000000..a05ac0716e
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/dev-mcelog.c
@@ -0,0 +1,373 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * /dev/mcelog driver
+ *
+ * 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/miscdevice.h>
+#include <linux/slab.h>
+#include <linux/kmod.h>
+#include <linux/poll.h>
+
+#include "internal.h"
+
+static BLOCKING_NOTIFIER_HEAD(mce_injector_chain);
+
+static DEFINE_MUTEX(mce_chrdev_read_mutex);
+
+static char mce_helper[128];
+static char *mce_helper_argv[2] = { mce_helper, NULL };
+
+/*
+ * 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_buffer *mcelog;
+
+static DECLARE_WAIT_QUEUE_HEAD(mce_chrdev_wait);
+
+static int dev_mce_log(struct notifier_block *nb, unsigned long val,
+				void *data)
+{
+	struct mce *mce = (struct mce *)data;
+	unsigned int entry;
+
+	if (mce->kflags & MCE_HANDLED_CEC)
+		return NOTIFY_DONE;
+
+	mutex_lock(&mce_chrdev_read_mutex);
+
+	entry = mcelog->next;
+
+	/*
+	 * When the buffer fills up discard new entries. Assume that the
+	 * earlier errors are the more interesting ones:
+	 */
+	if (entry >= mcelog->len) {
+		set_bit(MCE_OVERFLOW, (unsigned long *)&mcelog->flags);
+		goto unlock;
+	}
+
+	mcelog->next = entry + 1;
+
+	memcpy(mcelog->entry + entry, mce, sizeof(struct mce));
+	mcelog->entry[entry].finished = 1;
+	mcelog->entry[entry].kflags = 0;
+
+	/* wake processes polling /dev/mcelog */
+	wake_up_interruptible(&mce_chrdev_wait);
+
+unlock:
+	mutex_unlock(&mce_chrdev_read_mutex);
+
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD)
+		mce->kflags |= MCE_HANDLED_MCELOG;
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block dev_mcelog_nb = {
+	.notifier_call	= dev_mce_log,
+	.priority	= MCE_PRIO_MCELOG,
+};
+
+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);
+
+
+void mce_work_trigger(void)
+{
+	if (mce_helper[0])
+		schedule_work(&mce_trigger_work);
+}
+
+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;
+
+	strscpy(mce_helper, buf, sizeof(mce_helper));
+	p = strchr(mce_helper, '\n');
+
+	if (p)
+		*p = 0;
+
+	return strlen(mce_helper) + !!p;
+}
+
+DEVICE_ATTR(trigger, 0644, show_trigger, set_trigger);
+
+/*
+ * 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 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 next;
+	int i, err;
+
+	mutex_lock(&mce_chrdev_read_mutex);
+
+	if (!mce_apei_read_done) {
+		err = __mce_read_apei(&buf, usize);
+		if (err || buf != ubuf)
+			goto out;
+	}
+
+	/* Only supports full reads right now */
+	err = -EINVAL;
+	if (*off != 0 || usize < mcelog->len * sizeof(struct mce))
+		goto out;
+
+	next = mcelog->next;
+	err = 0;
+
+	for (i = 0; i < next; i++) {
+		struct mce *m = &mcelog->entry[i];
+
+		err |= copy_to_user(buf, m, sizeof(*m));
+		buf += sizeof(*m);
+	}
+
+	memset(mcelog->entry, 0, next * sizeof(struct mce));
+	mcelog->next = 0;
+
+	if (err)
+		err = -EFAULT;
+
+out:
+	mutex_unlock(&mce_chrdev_read_mutex);
+
+	return err ? err : buf - ubuf;
+}
+
+static __poll_t mce_chrdev_poll(struct file *file, poll_table *wait)
+{
+	poll_wait(file, &mce_chrdev_wait, wait);
+	if (READ_ONCE(mcelog->next))
+		return EPOLLIN | EPOLLRDNORM;
+	if (!mce_apei_read_done && apei_check_mce())
+		return EPOLLIN | EPOLLRDNORM;
+	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(mcelog->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;
+	}
+}
+
+void mce_register_injector_chain(struct notifier_block *nb)
+{
+	blocking_notifier_chain_register(&mce_injector_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_register_injector_chain);
+
+void mce_unregister_injector_chain(struct notifier_block *nb)
+{
+	blocking_notifier_chain_unregister(&mce_injector_chain, nb);
+}
+EXPORT_SYMBOL_GPL(mce_unregister_injector_chain);
+
+static ssize_t mce_chrdev_write(struct file *filp, const char __user *ubuf,
+				size_t usize, loff_t *off)
+{
+	struct mce m;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+	/*
+	 * There are some cases where real MSR reads could slip
+	 * through.
+	 */
+	if (!boot_cpu_has(X86_FEATURE_MCE) || !boot_cpu_has(X86_FEATURE_MCA))
+		return -EIO;
+
+	if ((unsigned long)usize > sizeof(struct mce))
+		usize = sizeof(struct mce);
+	if (copy_from_user(&m, ubuf, usize))
+		return -EFAULT;
+
+	if (m.extcpu >= num_possible_cpus() || !cpu_online(m.extcpu))
+		return -EINVAL;
+
+	/*
+	 * Need to give user space some time to set everything up,
+	 * so do it a jiffie or two later everywhere.
+	 */
+	schedule_timeout(2);
+
+	blocking_notifier_call_chain(&mce_injector_chain, 0, &m);
+
+	return usize;
+}
+
+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,
+	.compat_ioctl		= compat_ptr_ioctl,
+	.llseek			= no_llseek,
+};
+
+static struct miscdevice mce_chrdev_device = {
+	MISC_MCELOG_MINOR,
+	"mcelog",
+	&mce_chrdev_ops,
+};
+
+static __init int dev_mcelog_init_device(void)
+{
+	int mce_log_len;
+	int err;
+
+	mce_log_len = max(MCE_LOG_MIN_LEN, num_online_cpus());
+	mcelog = kzalloc(struct_size(mcelog, entry, mce_log_len), GFP_KERNEL);
+	if (!mcelog)
+		return -ENOMEM;
+
+	memcpy(mcelog->signature, MCE_LOG_SIGNATURE, sizeof(mcelog->signature));
+	mcelog->len = mce_log_len;
+	mcelog->recordlen = sizeof(struct mce);
+
+	/* register character device /dev/mcelog */
+	err = misc_register(&mce_chrdev_device);
+	if (err) {
+		if (err == -EBUSY)
+			/* Xen dom0 might have registered the device already. */
+			pr_info("Unable to init device /dev/mcelog, already registered");
+		else
+			pr_err("Unable to init device /dev/mcelog (rc: %d)\n", err);
+
+		kfree(mcelog);
+		return err;
+	}
+
+	mce_register_decode_chain(&dev_mcelog_nb);
+	return 0;
+}
+device_initcall_sync(dev_mcelog_init_device);
diff --git a/arch/x86/kernel/cpu/mce/genpool.c b/arch/x86/kernel/cpu/mce/genpool.c
new file mode 100644
index 0000000000..fbe8b61c34
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/genpool.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MCE event pool management in MCE context
+ *
+ * Copyright (C) 2015 Intel Corp.
+ * Author: Chen, Gong <gong.chen@linux.intel.com>
+ */
+#include <linux/smp.h>
+#include <linux/mm.h>
+#include <linux/genalloc.h>
+#include <linux/llist.h>
+#include "internal.h"
+
+/*
+ * printk() is not safe in MCE context. This is a lock-less memory allocator
+ * used to save error information organized in a lock-less list.
+ *
+ * This memory pool is only to be used to save MCE records in MCE context.
+ * MCE events are rare, so a fixed size memory pool should be enough. Use
+ * 2 pages to save MCE events for now (~80 MCE records at most).
+ */
+#define MCE_POOLSZ	(2 * PAGE_SIZE)
+
+static struct gen_pool *mce_evt_pool;
+static LLIST_HEAD(mce_event_llist);
+static char gen_pool_buf[MCE_POOLSZ];
+
+/*
+ * Compare the record "t" with each of the records on list "l" to see if
+ * an equivalent one is present in the list.
+ */
+static bool is_duplicate_mce_record(struct mce_evt_llist *t, struct mce_evt_llist *l)
+{
+	struct mce_evt_llist *node;
+	struct mce *m1, *m2;
+
+	m1 = &t->mce;
+
+	llist_for_each_entry(node, &l->llnode, llnode) {
+		m2 = &node->mce;
+
+		if (!mce_cmp(m1, m2))
+			return true;
+	}
+	return false;
+}
+
+/*
+ * The system has panicked - we'd like to peruse the list of MCE records
+ * that have been queued, but not seen by anyone yet.  The list is in
+ * reverse time order, so we need to reverse it. While doing that we can
+ * also drop duplicate records (these were logged because some banks are
+ * shared between cores or by all threads on a socket).
+ */
+struct llist_node *mce_gen_pool_prepare_records(void)
+{
+	struct llist_node *head;
+	LLIST_HEAD(new_head);
+	struct mce_evt_llist *node, *t;
+
+	head = llist_del_all(&mce_event_llist);
+	if (!head)
+		return NULL;
+
+	/* squeeze out duplicates while reversing order */
+	llist_for_each_entry_safe(node, t, head, llnode) {
+		if (!is_duplicate_mce_record(node, t))
+			llist_add(&node->llnode, &new_head);
+	}
+
+	return new_head.first;
+}
+
+void mce_gen_pool_process(struct work_struct *__unused)
+{
+	struct llist_node *head;
+	struct mce_evt_llist *node, *tmp;
+	struct mce *mce;
+
+	head = llist_del_all(&mce_event_llist);
+	if (!head)
+		return;
+
+	head = llist_reverse_order(head);
+	llist_for_each_entry_safe(node, tmp, head, llnode) {
+		mce = &node->mce;
+		blocking_notifier_call_chain(&x86_mce_decoder_chain, 0, mce);
+		gen_pool_free(mce_evt_pool, (unsigned long)node, sizeof(*node));
+	}
+}
+
+bool mce_gen_pool_empty(void)
+{
+	return llist_empty(&mce_event_llist);
+}
+
+int mce_gen_pool_add(struct mce *mce)
+{
+	struct mce_evt_llist *node;
+
+	if (filter_mce(mce))
+		return -EINVAL;
+
+	if (!mce_evt_pool)
+		return -EINVAL;
+
+	node = (void *)gen_pool_alloc(mce_evt_pool, sizeof(*node));
+	if (!node) {
+		pr_warn_ratelimited("MCE records pool full!\n");
+		return -ENOMEM;
+	}
+
+	memcpy(&node->mce, mce, sizeof(*mce));
+	llist_add(&node->llnode, &mce_event_llist);
+
+	return 0;
+}
+
+static int mce_gen_pool_create(void)
+{
+	struct gen_pool *tmpp;
+	int ret = -ENOMEM;
+
+	tmpp = gen_pool_create(ilog2(sizeof(struct mce_evt_llist)), -1);
+	if (!tmpp)
+		goto out;
+
+	ret = gen_pool_add(tmpp, (unsigned long)gen_pool_buf, MCE_POOLSZ, -1);
+	if (ret) {
+		gen_pool_destroy(tmpp);
+		goto out;
+	}
+
+	mce_evt_pool = tmpp;
+
+out:
+	return ret;
+}
+
+int mce_gen_pool_init(void)
+{
+	/* Just init mce_gen_pool once. */
+	if (mce_evt_pool)
+		return 0;
+
+	return mce_gen_pool_create();
+}
diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
new file mode 100644
index 0000000000..72f0695c3d
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/inject.c
@@ -0,0 +1,800 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Machine check injection support.
+ * Copyright 2008 Intel Corporation.
+ *
+ * Authors:
+ * Andi Kleen
+ * Ying Huang
+ *
+ * The AMD part (from mce_amd_inj.c): a simple MCE injection facility
+ * for testing different aspects of the RAS code. This driver should be
+ * built as module so that it can be loaded on production kernels for
+ * testing purposes.
+ *
+ * Copyright (c) 2010-17:  Borislav Petkov <bp@alien8.de>
+ *			   Advanced Micro Devices Inc.
+ */
+
+#include <linux/cpu.h>
+#include <linux/debugfs.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/pci.h>
+#include <linux/uaccess.h>
+
+#include <asm/amd_nb.h>
+#include <asm/apic.h>
+#include <asm/irq_vectors.h>
+#include <asm/mce.h>
+#include <asm/nmi.h>
+#include <asm/smp.h>
+
+#include "internal.h"
+
+static bool hw_injection_possible = true;
+
+/*
+ * Collect all the MCi_XXX settings
+ */
+static struct mce i_mce;
+static struct dentry *dfs_inj;
+
+#define MAX_FLAG_OPT_SIZE	4
+#define NBCFG			0x44
+
+enum injection_type {
+	SW_INJ = 0,	/* SW injection, simply decode the error */
+	HW_INJ,		/* Trigger a #MC */
+	DFR_INT_INJ,    /* Trigger Deferred error interrupt */
+	THR_INT_INJ,    /* Trigger threshold interrupt */
+	N_INJ_TYPES,
+};
+
+static const char * const flags_options[] = {
+	[SW_INJ] = "sw",
+	[HW_INJ] = "hw",
+	[DFR_INT_INJ] = "df",
+	[THR_INT_INJ] = "th",
+	NULL
+};
+
+/* Set default injection to SW_INJ */
+static enum injection_type inj_type = SW_INJ;
+
+#define MCE_INJECT_SET(reg)						\
+static int inj_##reg##_set(void *data, u64 val)				\
+{									\
+	struct mce *m = (struct mce *)data;				\
+									\
+	m->reg = val;							\
+	return 0;							\
+}
+
+MCE_INJECT_SET(status);
+MCE_INJECT_SET(misc);
+MCE_INJECT_SET(addr);
+MCE_INJECT_SET(synd);
+
+#define MCE_INJECT_GET(reg)						\
+static int inj_##reg##_get(void *data, u64 *val)			\
+{									\
+	struct mce *m = (struct mce *)data;				\
+									\
+	*val = m->reg;							\
+	return 0;							\
+}
+
+MCE_INJECT_GET(status);
+MCE_INJECT_GET(misc);
+MCE_INJECT_GET(addr);
+MCE_INJECT_GET(synd);
+MCE_INJECT_GET(ipid);
+
+DEFINE_SIMPLE_ATTRIBUTE(status_fops, inj_status_get, inj_status_set, "%llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(misc_fops, inj_misc_get, inj_misc_set, "%llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(addr_fops, inj_addr_get, inj_addr_set, "%llx\n");
+DEFINE_SIMPLE_ATTRIBUTE(synd_fops, inj_synd_get, inj_synd_set, "%llx\n");
+
+/* Use the user provided IPID value on a sw injection. */
+static int inj_ipid_set(void *data, u64 val)
+{
+	struct mce *m = (struct mce *)data;
+
+	if (cpu_feature_enabled(X86_FEATURE_SMCA)) {
+		if (inj_type == SW_INJ)
+			m->ipid = val;
+	}
+
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(ipid_fops, inj_ipid_get, inj_ipid_set, "%llx\n");
+
+static void setup_inj_struct(struct mce *m)
+{
+	memset(m, 0, sizeof(struct mce));
+
+	m->cpuvendor = boot_cpu_data.x86_vendor;
+	m->time	     = ktime_get_real_seconds();
+	m->cpuid     = cpuid_eax(1);
+	m->microcode = boot_cpu_data.microcode;
+}
+
+/* Update fake mce registers on current CPU. */
+static void inject_mce(struct mce *m)
+{
+	struct mce *i = &per_cpu(injectm, m->extcpu);
+
+	/* Make sure no one reads partially written injectm */
+	i->finished = 0;
+	mb();
+	m->finished = 0;
+	/* First set the fields after finished */
+	i->extcpu = m->extcpu;
+	mb();
+	/* Now write record in order, finished last (except above) */
+	memcpy(i, m, sizeof(struct mce));
+	/* Finally activate it */
+	mb();
+	i->finished = 1;
+}
+
+static void raise_poll(struct mce *m)
+{
+	unsigned long flags;
+	mce_banks_t b;
+
+	memset(&b, 0xff, sizeof(mce_banks_t));
+	local_irq_save(flags);
+	machine_check_poll(0, &b);
+	local_irq_restore(flags);
+	m->finished = 0;
+}
+
+static void raise_exception(struct mce *m, struct pt_regs *pregs)
+{
+	struct pt_regs regs;
+	unsigned long flags;
+
+	if (!pregs) {
+		memset(&regs, 0, sizeof(struct pt_regs));
+		regs.ip = m->ip;
+		regs.cs = m->cs;
+		pregs = &regs;
+	}
+	/* do_machine_check() expects interrupts disabled -- at least */
+	local_irq_save(flags);
+	do_machine_check(pregs);
+	local_irq_restore(flags);
+	m->finished = 0;
+}
+
+static cpumask_var_t mce_inject_cpumask;
+static DEFINE_MUTEX(mce_inject_mutex);
+
+static int mce_raise_notify(unsigned int cmd, struct pt_regs *regs)
+{
+	int cpu = smp_processor_id();
+	struct mce *m = this_cpu_ptr(&injectm);
+	if (!cpumask_test_cpu(cpu, mce_inject_cpumask))
+		return NMI_DONE;
+	cpumask_clear_cpu(cpu, mce_inject_cpumask);
+	if (m->inject_flags & MCJ_EXCEPTION)
+		raise_exception(m, regs);
+	else if (m->status)
+		raise_poll(m);
+	return NMI_HANDLED;
+}
+
+static void mce_irq_ipi(void *info)
+{
+	int cpu = smp_processor_id();
+	struct mce *m = this_cpu_ptr(&injectm);
+
+	if (cpumask_test_cpu(cpu, mce_inject_cpumask) &&
+			m->inject_flags & MCJ_EXCEPTION) {
+		cpumask_clear_cpu(cpu, mce_inject_cpumask);
+		raise_exception(m, NULL);
+	}
+}
+
+/* Inject mce on current CPU */
+static int raise_local(void)
+{
+	struct mce *m = this_cpu_ptr(&injectm);
+	int context = MCJ_CTX(m->inject_flags);
+	int ret = 0;
+	int cpu = m->extcpu;
+
+	if (m->inject_flags & MCJ_EXCEPTION) {
+		pr_info("Triggering MCE exception on CPU %d\n", cpu);
+		switch (context) {
+		case MCJ_CTX_IRQ:
+			/*
+			 * Could do more to fake interrupts like
+			 * calling irq_enter, but the necessary
+			 * machinery isn't exported currently.
+			 */
+			fallthrough;
+		case MCJ_CTX_PROCESS:
+			raise_exception(m, NULL);
+			break;
+		default:
+			pr_info("Invalid MCE context\n");
+			ret = -EINVAL;
+		}
+		pr_info("MCE exception done on CPU %d\n", cpu);
+	} else if (m->status) {
+		pr_info("Starting machine check poll CPU %d\n", cpu);
+		raise_poll(m);
+		mce_notify_irq();
+		pr_info("Machine check poll done on CPU %d\n", cpu);
+	} else
+		m->finished = 0;
+
+	return ret;
+}
+
+static void __maybe_unused raise_mce(struct mce *m)
+{
+	int context = MCJ_CTX(m->inject_flags);
+
+	inject_mce(m);
+
+	if (context == MCJ_CTX_RANDOM)
+		return;
+
+	if (m->inject_flags & (MCJ_IRQ_BROADCAST | MCJ_NMI_BROADCAST)) {
+		unsigned long start;
+		int cpu;
+
+		cpus_read_lock();
+		cpumask_copy(mce_inject_cpumask, cpu_online_mask);
+		cpumask_clear_cpu(get_cpu(), mce_inject_cpumask);
+		for_each_online_cpu(cpu) {
+			struct mce *mcpu = &per_cpu(injectm, cpu);
+			if (!mcpu->finished ||
+			    MCJ_CTX(mcpu->inject_flags) != MCJ_CTX_RANDOM)
+				cpumask_clear_cpu(cpu, mce_inject_cpumask);
+		}
+		if (!cpumask_empty(mce_inject_cpumask)) {
+			if (m->inject_flags & MCJ_IRQ_BROADCAST) {
+				/*
+				 * don't wait because mce_irq_ipi is necessary
+				 * to be sync with following raise_local
+				 */
+				preempt_disable();
+				smp_call_function_many(mce_inject_cpumask,
+					mce_irq_ipi, NULL, 0);
+				preempt_enable();
+			} else if (m->inject_flags & MCJ_NMI_BROADCAST)
+				__apic_send_IPI_mask(mce_inject_cpumask, NMI_VECTOR);
+		}
+		start = jiffies;
+		while (!cpumask_empty(mce_inject_cpumask)) {
+			if (!time_before(jiffies, start + 2*HZ)) {
+				pr_err("Timeout waiting for mce inject %lx\n",
+					*cpumask_bits(mce_inject_cpumask));
+				break;
+			}
+			cpu_relax();
+		}
+		raise_local();
+		put_cpu();
+		cpus_read_unlock();
+	} else {
+		preempt_disable();
+		raise_local();
+		preempt_enable();
+	}
+}
+
+static int mce_inject_raise(struct notifier_block *nb, unsigned long val,
+			    void *data)
+{
+	struct mce *m = (struct mce *)data;
+
+	if (!m)
+		return NOTIFY_DONE;
+
+	mutex_lock(&mce_inject_mutex);
+	raise_mce(m);
+	mutex_unlock(&mce_inject_mutex);
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block inject_nb = {
+	.notifier_call  = mce_inject_raise,
+};
+
+/*
+ * Caller needs to be make sure this cpu doesn't disappear
+ * from under us, i.e.: get_cpu/put_cpu.
+ */
+static int toggle_hw_mce_inject(unsigned int cpu, bool enable)
+{
+	u32 l, h;
+	int err;
+
+	err = rdmsr_on_cpu(cpu, MSR_K7_HWCR, &l, &h);
+	if (err) {
+		pr_err("%s: error reading HWCR\n", __func__);
+		return err;
+	}
+
+	enable ? (l |= BIT(18)) : (l &= ~BIT(18));
+
+	err = wrmsr_on_cpu(cpu, MSR_K7_HWCR, l, h);
+	if (err)
+		pr_err("%s: error writing HWCR\n", __func__);
+
+	return err;
+}
+
+static int __set_inj(const char *buf)
+{
+	int i;
+
+	for (i = 0; i < N_INJ_TYPES; i++) {
+		if (!strncmp(flags_options[i], buf, strlen(flags_options[i]))) {
+			if (i > SW_INJ && !hw_injection_possible)
+				continue;
+			inj_type = i;
+			return 0;
+		}
+	}
+	return -EINVAL;
+}
+
+static ssize_t flags_read(struct file *filp, char __user *ubuf,
+			  size_t cnt, loff_t *ppos)
+{
+	char buf[MAX_FLAG_OPT_SIZE];
+	int n;
+
+	n = sprintf(buf, "%s\n", flags_options[inj_type]);
+
+	return simple_read_from_buffer(ubuf, cnt, ppos, buf, n);
+}
+
+static ssize_t flags_write(struct file *filp, const char __user *ubuf,
+			   size_t cnt, loff_t *ppos)
+{
+	char buf[MAX_FLAG_OPT_SIZE], *__buf;
+	int err;
+
+	if (!cnt || cnt > MAX_FLAG_OPT_SIZE)
+		return -EINVAL;
+
+	if (copy_from_user(&buf, ubuf, cnt))
+		return -EFAULT;
+
+	buf[cnt - 1] = 0;
+
+	/* strip whitespace */
+	__buf = strstrip(buf);
+
+	err = __set_inj(__buf);
+	if (err) {
+		pr_err("%s: Invalid flags value: %s\n", __func__, __buf);
+		return err;
+	}
+
+	*ppos += cnt;
+
+	return cnt;
+}
+
+static const struct file_operations flags_fops = {
+	.read           = flags_read,
+	.write          = flags_write,
+	.llseek         = generic_file_llseek,
+};
+
+/*
+ * On which CPU to inject?
+ */
+MCE_INJECT_GET(extcpu);
+
+static int inj_extcpu_set(void *data, u64 val)
+{
+	struct mce *m = (struct mce *)data;
+
+	if (val >= nr_cpu_ids || !cpu_online(val)) {
+		pr_err("%s: Invalid CPU: %llu\n", __func__, val);
+		return -EINVAL;
+	}
+	m->extcpu = val;
+	return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(extcpu_fops, inj_extcpu_get, inj_extcpu_set, "%llu\n");
+
+static void trigger_mce(void *info)
+{
+	asm volatile("int $18");
+}
+
+static void trigger_dfr_int(void *info)
+{
+	asm volatile("int %0" :: "i" (DEFERRED_ERROR_VECTOR));
+}
+
+static void trigger_thr_int(void *info)
+{
+	asm volatile("int %0" :: "i" (THRESHOLD_APIC_VECTOR));
+}
+
+static u32 get_nbc_for_node(int node_id)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+	u32 cores_per_node;
+
+	cores_per_node = (c->x86_max_cores * smp_num_siblings) / amd_get_nodes_per_socket();
+
+	return cores_per_node * node_id;
+}
+
+static void toggle_nb_mca_mst_cpu(u16 nid)
+{
+	struct amd_northbridge *nb;
+	struct pci_dev *F3;
+	u32 val;
+	int err;
+
+	nb = node_to_amd_nb(nid);
+	if (!nb)
+		return;
+
+	F3 = nb->misc;
+	if (!F3)
+		return;
+
+	err = pci_read_config_dword(F3, NBCFG, &val);
+	if (err) {
+		pr_err("%s: Error reading F%dx%03x.\n",
+		       __func__, PCI_FUNC(F3->devfn), NBCFG);
+		return;
+	}
+
+	if (val & BIT(27))
+		return;
+
+	pr_err("%s: Set D18F3x44[NbMcaToMstCpuEn] which BIOS hasn't done.\n",
+	       __func__);
+
+	val |= BIT(27);
+	err = pci_write_config_dword(F3, NBCFG, val);
+	if (err)
+		pr_err("%s: Error writing F%dx%03x.\n",
+		       __func__, PCI_FUNC(F3->devfn), NBCFG);
+}
+
+static void prepare_msrs(void *info)
+{
+	struct mce m = *(struct mce *)info;
+	u8 b = m.bank;
+
+	wrmsrl(MSR_IA32_MCG_STATUS, m.mcgstatus);
+
+	if (boot_cpu_has(X86_FEATURE_SMCA)) {
+		if (m.inject_flags == DFR_INT_INJ) {
+			wrmsrl(MSR_AMD64_SMCA_MCx_DESTAT(b), m.status);
+			wrmsrl(MSR_AMD64_SMCA_MCx_DEADDR(b), m.addr);
+		} else {
+			wrmsrl(MSR_AMD64_SMCA_MCx_STATUS(b), m.status);
+			wrmsrl(MSR_AMD64_SMCA_MCx_ADDR(b), m.addr);
+		}
+
+		wrmsrl(MSR_AMD64_SMCA_MCx_MISC(b), m.misc);
+		wrmsrl(MSR_AMD64_SMCA_MCx_SYND(b), m.synd);
+	} else {
+		wrmsrl(MSR_IA32_MCx_STATUS(b), m.status);
+		wrmsrl(MSR_IA32_MCx_ADDR(b), m.addr);
+		wrmsrl(MSR_IA32_MCx_MISC(b), m.misc);
+	}
+}
+
+static void do_inject(void)
+{
+	u64 mcg_status = 0;
+	unsigned int cpu = i_mce.extcpu;
+	u8 b = i_mce.bank;
+
+	i_mce.tsc = rdtsc_ordered();
+
+	i_mce.status |= MCI_STATUS_VAL;
+
+	if (i_mce.misc)
+		i_mce.status |= MCI_STATUS_MISCV;
+
+	if (i_mce.synd)
+		i_mce.status |= MCI_STATUS_SYNDV;
+
+	if (inj_type == SW_INJ) {
+		mce_log(&i_mce);
+		return;
+	}
+
+	/* prep MCE global settings for the injection */
+	mcg_status = MCG_STATUS_MCIP | MCG_STATUS_EIPV;
+
+	if (!(i_mce.status & MCI_STATUS_PCC))
+		mcg_status |= MCG_STATUS_RIPV;
+
+	/*
+	 * Ensure necessary status bits for deferred errors:
+	 * - MCx_STATUS[Deferred]: make sure it is a deferred error
+	 * - MCx_STATUS[UC] cleared: deferred errors are _not_ UC
+	 */
+	if (inj_type == DFR_INT_INJ) {
+		i_mce.status |= MCI_STATUS_DEFERRED;
+		i_mce.status &= ~MCI_STATUS_UC;
+	}
+
+	/*
+	 * For multi node CPUs, logging and reporting of bank 4 errors happens
+	 * only on the node base core. Refer to D18F3x44[NbMcaToMstCpuEn] for
+	 * Fam10h and later BKDGs.
+	 */
+	if (boot_cpu_has(X86_FEATURE_AMD_DCM) &&
+	    b == 4 &&
+	    boot_cpu_data.x86 < 0x17) {
+		toggle_nb_mca_mst_cpu(topology_die_id(cpu));
+		cpu = get_nbc_for_node(topology_die_id(cpu));
+	}
+
+	cpus_read_lock();
+	if (!cpu_online(cpu))
+		goto err;
+
+	toggle_hw_mce_inject(cpu, true);
+
+	i_mce.mcgstatus = mcg_status;
+	i_mce.inject_flags = inj_type;
+	smp_call_function_single(cpu, prepare_msrs, &i_mce, 0);
+
+	toggle_hw_mce_inject(cpu, false);
+
+	switch (inj_type) {
+	case DFR_INT_INJ:
+		smp_call_function_single(cpu, trigger_dfr_int, NULL, 0);
+		break;
+	case THR_INT_INJ:
+		smp_call_function_single(cpu, trigger_thr_int, NULL, 0);
+		break;
+	default:
+		smp_call_function_single(cpu, trigger_mce, NULL, 0);
+	}
+
+err:
+	cpus_read_unlock();
+
+}
+
+/*
+ * This denotes into which bank we're injecting and triggers
+ * the injection, at the same time.
+ */
+static int inj_bank_set(void *data, u64 val)
+{
+	struct mce *m = (struct mce *)data;
+	u8 n_banks;
+	u64 cap;
+
+	/* Get bank count on target CPU so we can handle non-uniform values. */
+	rdmsrl_on_cpu(m->extcpu, MSR_IA32_MCG_CAP, &cap);
+	n_banks = cap & MCG_BANKCNT_MASK;
+
+	if (val >= n_banks) {
+		pr_err("MCA bank %llu non-existent on CPU%d\n", val, m->extcpu);
+		return -EINVAL;
+	}
+
+	m->bank = val;
+
+	/*
+	 * sw-only injection allows to write arbitrary values into the MCA
+	 * registers because it tests only the decoding paths.
+	 */
+	if (inj_type == SW_INJ)
+		goto inject;
+
+	/*
+	 * Read IPID value to determine if a bank is populated on the target
+	 * CPU.
+	 */
+	if (cpu_feature_enabled(X86_FEATURE_SMCA)) {
+		u64 ipid;
+
+		if (rdmsrl_on_cpu(m->extcpu, MSR_AMD64_SMCA_MCx_IPID(val), &ipid)) {
+			pr_err("Error reading IPID on CPU%d\n", m->extcpu);
+			return -EINVAL;
+		}
+
+		if (!ipid) {
+			pr_err("Cannot inject into unpopulated bank %llu\n", val);
+			return -ENODEV;
+		}
+	}
+
+inject:
+	do_inject();
+
+	/* Reset injection struct */
+	setup_inj_struct(&i_mce);
+
+	return 0;
+}
+
+MCE_INJECT_GET(bank);
+
+DEFINE_SIMPLE_ATTRIBUTE(bank_fops, inj_bank_get, inj_bank_set, "%llu\n");
+
+static const char readme_msg[] =
+"Description of the files and their usages:\n"
+"\n"
+"Note1: i refers to the bank number below.\n"
+"Note2: See respective BKDGs for the exact bit definitions of the files below\n"
+"as they mirror the hardware registers.\n"
+"\n"
+"status:\t Set MCi_STATUS: the bits in that MSR control the error type and\n"
+"\t attributes of the error which caused the MCE.\n"
+"\n"
+"misc:\t Set MCi_MISC: provide auxiliary info about the error. It is mostly\n"
+"\t used for error thresholding purposes and its validity is indicated by\n"
+"\t MCi_STATUS[MiscV].\n"
+"\n"
+"synd:\t Set MCi_SYND: provide syndrome info about the error. Only valid on\n"
+"\t Scalable MCA systems, and its validity is indicated by MCi_STATUS[SyndV].\n"
+"\n"
+"addr:\t Error address value to be written to MCi_ADDR. Log address information\n"
+"\t associated with the error.\n"
+"\n"
+"cpu:\t The CPU to inject the error on.\n"
+"\n"
+"bank:\t Specify the bank you want to inject the error into: the number of\n"
+"\t banks in a processor varies and is family/model-specific, therefore, the\n"
+"\t supplied value is sanity-checked. Setting the bank value also triggers the\n"
+"\t injection.\n"
+"\n"
+"flags:\t Injection type to be performed. Writing to this file will trigger a\n"
+"\t real machine check, an APIC interrupt or invoke the error decoder routines\n"
+"\t for AMD processors.\n"
+"\n"
+"\t Allowed error injection types:\n"
+"\t  - \"sw\": Software error injection. Decode error to a human-readable \n"
+"\t    format only. Safe to use.\n"
+"\t  - \"hw\": Hardware error injection. Causes the #MC exception handler to \n"
+"\t    handle the error. Be warned: might cause system panic if MCi_STATUS[PCC] \n"
+"\t    is set. Therefore, consider setting (debugfs_mountpoint)/mce/fake_panic \n"
+"\t    before injecting.\n"
+"\t  - \"df\": Trigger APIC interrupt for Deferred error. Causes deferred \n"
+"\t    error APIC interrupt handler to handle the error if the feature is \n"
+"\t    is present in hardware. \n"
+"\t  - \"th\": Trigger APIC interrupt for Threshold errors. Causes threshold \n"
+"\t    APIC interrupt handler to handle the error. \n"
+"\n"
+"ipid:\t IPID (AMD-specific)\n"
+"\n";
+
+static ssize_t
+inj_readme_read(struct file *filp, char __user *ubuf,
+		       size_t cnt, loff_t *ppos)
+{
+	return simple_read_from_buffer(ubuf, cnt, ppos,
+					readme_msg, strlen(readme_msg));
+}
+
+static const struct file_operations readme_fops = {
+	.read		= inj_readme_read,
+};
+
+static struct dfs_node {
+	char *name;
+	const struct file_operations *fops;
+	umode_t perm;
+} dfs_fls[] = {
+	{ .name = "status",	.fops = &status_fops, .perm = S_IRUSR | S_IWUSR },
+	{ .name = "misc",	.fops = &misc_fops,   .perm = S_IRUSR | S_IWUSR },
+	{ .name = "addr",	.fops = &addr_fops,   .perm = S_IRUSR | S_IWUSR },
+	{ .name = "synd",	.fops = &synd_fops,   .perm = S_IRUSR | S_IWUSR },
+	{ .name = "ipid",	.fops = &ipid_fops,   .perm = S_IRUSR | S_IWUSR },
+	{ .name = "bank",	.fops = &bank_fops,   .perm = S_IRUSR | S_IWUSR },
+	{ .name = "flags",	.fops = &flags_fops,  .perm = S_IRUSR | S_IWUSR },
+	{ .name = "cpu",	.fops = &extcpu_fops, .perm = S_IRUSR | S_IWUSR },
+	{ .name = "README",	.fops = &readme_fops, .perm = S_IRUSR | S_IRGRP | S_IROTH },
+};
+
+static void __init debugfs_init(void)
+{
+	unsigned int i;
+
+	dfs_inj = debugfs_create_dir("mce-inject", NULL);
+
+	for (i = 0; i < ARRAY_SIZE(dfs_fls); i++)
+		debugfs_create_file(dfs_fls[i].name, dfs_fls[i].perm, dfs_inj,
+				    &i_mce, dfs_fls[i].fops);
+}
+
+static void check_hw_inj_possible(void)
+{
+	int cpu;
+	u8 bank;
+
+	/*
+	 * This behavior exists only on SMCA systems though its not directly
+	 * related to SMCA.
+	 */
+	if (!cpu_feature_enabled(X86_FEATURE_SMCA))
+		return;
+
+	cpu = get_cpu();
+
+	for (bank = 0; bank < MAX_NR_BANKS; ++bank) {
+		u64 status = MCI_STATUS_VAL, ipid;
+
+		/* Check whether bank is populated */
+		rdmsrl(MSR_AMD64_SMCA_MCx_IPID(bank), ipid);
+		if (!ipid)
+			continue;
+
+		toggle_hw_mce_inject(cpu, true);
+
+		wrmsrl_safe(mca_msr_reg(bank, MCA_STATUS), status);
+		rdmsrl_safe(mca_msr_reg(bank, MCA_STATUS), &status);
+		wrmsrl_safe(mca_msr_reg(bank, MCA_STATUS), 0);
+
+		if (!status) {
+			hw_injection_possible = false;
+			pr_warn("Platform does not allow *hardware* error injection."
+				"Try using APEI EINJ instead.\n");
+		}
+
+		toggle_hw_mce_inject(cpu, false);
+
+		break;
+	}
+
+	put_cpu();
+}
+
+static int __init inject_init(void)
+{
+	if (!alloc_cpumask_var(&mce_inject_cpumask, GFP_KERNEL))
+		return -ENOMEM;
+
+	check_hw_inj_possible();
+
+	debugfs_init();
+
+	register_nmi_handler(NMI_LOCAL, mce_raise_notify, 0, "mce_notify");
+	mce_register_injector_chain(&inject_nb);
+
+	setup_inj_struct(&i_mce);
+
+	pr_info("Machine check injector initialized\n");
+
+	return 0;
+}
+
+static void __exit inject_exit(void)
+{
+
+	mce_unregister_injector_chain(&inject_nb);
+	unregister_nmi_handler(NMI_LOCAL, "mce_notify");
+
+	debugfs_remove_recursive(dfs_inj);
+	dfs_inj = NULL;
+
+	memset(&dfs_fls, 0, sizeof(dfs_fls));
+
+	free_cpumask_var(mce_inject_cpumask);
+}
+
+module_init(inject_init);
+module_exit(inject_exit);
+MODULE_LICENSE("GPL");
diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c
new file mode 100644
index 0000000000..f5323551c1
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/intel.c
@@ -0,0 +1,538 @@
+// 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);
+
+/*
+ * On systems that do support CMCI but it's disabled, polling for MCEs can
+ * cause the same event to be reported multiple times because IA32_MCi_STATUS
+ * is shared by the same package.
+ */
+static DEFINE_SPINLOCK(cmci_poll_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);
+}
+
+/* Bank polling function when CMCI is disabled. */
+static void cmci_mc_poll_banks(void)
+{
+	spin_lock(&cmci_poll_lock);
+	machine_check_poll(0, this_cpu_ptr(&mce_poll_banks));
+	spin_unlock(&cmci_poll_lock);
+}
+
+void intel_init_cmci(void)
+{
+	int banks;
+
+	if (!cmci_supported(&banks)) {
+		mc_poll_banks = cmci_mc_poll_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;
+}
diff --git a/arch/x86/kernel/cpu/mce/internal.h b/arch/x86/kernel/cpu/mce/internal.h
new file mode 100644
index 0000000000..bcf1b3c66c
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/internal.h
@@ -0,0 +1,281 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __X86_MCE_INTERNAL_H__
+#define __X86_MCE_INTERNAL_H__
+
+#undef pr_fmt
+#define pr_fmt(fmt) "mce: " fmt
+
+#include <linux/device.h>
+#include <asm/mce.h>
+
+enum severity_level {
+	MCE_NO_SEVERITY,
+	MCE_DEFERRED_SEVERITY,
+	MCE_UCNA_SEVERITY = MCE_DEFERRED_SEVERITY,
+	MCE_KEEP_SEVERITY,
+	MCE_SOME_SEVERITY,
+	MCE_AO_SEVERITY,
+	MCE_UC_SEVERITY,
+	MCE_AR_SEVERITY,
+	MCE_PANIC_SEVERITY,
+};
+
+extern struct blocking_notifier_head x86_mce_decoder_chain;
+
+#define INITIAL_CHECK_INTERVAL	5 * 60 /* 5 minutes */
+
+struct mce_evt_llist {
+	struct llist_node llnode;
+	struct mce mce;
+};
+
+void mce_gen_pool_process(struct work_struct *__unused);
+bool mce_gen_pool_empty(void);
+int mce_gen_pool_add(struct mce *mce);
+int mce_gen_pool_init(void);
+struct llist_node *mce_gen_pool_prepare_records(void);
+
+int mce_severity(struct mce *a, struct pt_regs *regs, char **msg, bool is_excp);
+struct dentry *mce_get_debugfs_dir(void);
+
+extern mce_banks_t mce_banks_ce_disabled;
+
+#ifdef CONFIG_X86_MCE_INTEL
+unsigned long cmci_intel_adjust_timer(unsigned long interval);
+bool mce_intel_cmci_poll(void);
+void mce_intel_hcpu_update(unsigned long cpu);
+void cmci_disable_bank(int bank);
+void intel_init_cmci(void);
+void intel_init_lmce(void);
+void intel_clear_lmce(void);
+bool intel_filter_mce(struct mce *m);
+#else
+# define cmci_intel_adjust_timer mce_adjust_timer_default
+static inline bool mce_intel_cmci_poll(void) { return false; }
+static inline void mce_intel_hcpu_update(unsigned long cpu) { }
+static inline void cmci_disable_bank(int bank) { }
+static inline void intel_init_cmci(void) { }
+static inline void intel_init_lmce(void) { }
+static inline void intel_clear_lmce(void) { }
+static inline bool intel_filter_mce(struct mce *m) { return false; }
+#endif
+
+void mce_timer_kick(unsigned long interval);
+
+#ifdef CONFIG_ACPI_APEI
+int apei_write_mce(struct mce *m);
+ssize_t apei_read_mce(struct mce *m, u64 *record_id);
+int apei_check_mce(void);
+int apei_clear_mce(u64 record_id);
+#else
+static inline int apei_write_mce(struct mce *m)
+{
+	return -EINVAL;
+}
+static inline ssize_t apei_read_mce(struct mce *m, u64 *record_id)
+{
+	return 0;
+}
+static inline int apei_check_mce(void)
+{
+	return 0;
+}
+static inline int apei_clear_mce(u64 record_id)
+{
+	return -EINVAL;
+}
+#endif
+
+/*
+ * We consider records to be equivalent if bank+status+addr+misc all match.
+ * This is only used when the system is going down because of a fatal error
+ * to avoid cluttering the console log with essentially repeated information.
+ * In normal processing all errors seen are logged.
+ */
+static inline bool mce_cmp(struct mce *m1, struct mce *m2)
+{
+	return m1->bank != m2->bank ||
+		m1->status != m2->status ||
+		m1->addr != m2->addr ||
+		m1->misc != m2->misc;
+}
+
+extern struct device_attribute dev_attr_trigger;
+
+#ifdef CONFIG_X86_MCELOG_LEGACY
+void mce_work_trigger(void);
+void mce_register_injector_chain(struct notifier_block *nb);
+void mce_unregister_injector_chain(struct notifier_block *nb);
+#else
+static inline void mce_work_trigger(void)	{ }
+static inline void mce_register_injector_chain(struct notifier_block *nb)	{ }
+static inline void mce_unregister_injector_chain(struct notifier_block *nb)	{ }
+#endif
+
+struct mca_config {
+	__u64 lmce_disabled		: 1,
+	      disabled			: 1,
+	      ser			: 1,
+	      recovery			: 1,
+	      bios_cmci_threshold	: 1,
+	      /* Proper #MC exception handler is set */
+	      initialized		: 1,
+	      __reserved		: 58;
+
+	bool dont_log_ce;
+	bool cmci_disabled;
+	bool ignore_ce;
+	bool print_all;
+
+	int monarch_timeout;
+	int panic_timeout;
+	u32 rip_msr;
+	s8 bootlog;
+};
+
+extern struct mca_config mca_cfg;
+DECLARE_PER_CPU_READ_MOSTLY(unsigned int, mce_num_banks);
+
+struct mce_vendor_flags {
+	/*
+	 * Indicates that overflow conditions are not fatal, when set.
+	 */
+	__u64 overflow_recov	: 1,
+
+	/*
+	 * (AMD) SUCCOR stands for S/W UnCorrectable error COntainment and
+	 * Recovery. It indicates support for data poisoning in HW and deferred
+	 * error interrupts.
+	 */
+	succor			: 1,
+
+	/*
+	 * (AMD) SMCA: This bit indicates support for Scalable MCA which expands
+	 * the register space for each MCA bank and also increases number of
+	 * banks. Also, to accommodate the new banks and registers, the MCA
+	 * register space is moved to a new MSR range.
+	 */
+	smca			: 1,
+
+	/* Zen IFU quirk */
+	zen_ifu_quirk		: 1,
+
+	/* AMD-style error thresholding banks present. */
+	amd_threshold		: 1,
+
+	/* Pentium, family 5-style MCA */
+	p5			: 1,
+
+	/* Centaur Winchip C6-style MCA */
+	winchip			: 1,
+
+	/* SandyBridge IFU quirk */
+	snb_ifu_quirk		: 1,
+
+	/* Skylake, Cascade Lake, Cooper Lake REP;MOVS* quirk */
+	skx_repmov_quirk	: 1,
+
+	__reserved_0		: 55;
+};
+
+extern struct mce_vendor_flags mce_flags;
+
+struct mce_bank {
+	/* subevents to enable */
+	u64			ctl;
+
+	/* initialise bank? */
+	__u64 init		: 1,
+
+	/*
+	 * (AMD) MCA_CONFIG[McaLsbInStatusSupported]: When set, this bit indicates
+	 * the LSB field is found in MCA_STATUS and not in MCA_ADDR.
+	 */
+	lsb_in_status		: 1,
+
+	__reserved_1		: 62;
+};
+
+DECLARE_PER_CPU_READ_MOSTLY(struct mce_bank[MAX_NR_BANKS], mce_banks_array);
+
+enum mca_msr {
+	MCA_CTL,
+	MCA_STATUS,
+	MCA_ADDR,
+	MCA_MISC,
+};
+
+/* Decide whether to add MCE record to MCE event pool or filter it out. */
+extern bool filter_mce(struct mce *m);
+
+#ifdef CONFIG_X86_MCE_AMD
+extern bool amd_filter_mce(struct mce *m);
+
+/*
+ * If MCA_CONFIG[McaLsbInStatusSupported] is set, extract ErrAddr in bits
+ * [56:0] of MCA_STATUS, else in bits [55:0] of MCA_ADDR.
+ */
+static __always_inline void smca_extract_err_addr(struct mce *m)
+{
+	u8 lsb;
+
+	if (!mce_flags.smca)
+		return;
+
+	if (this_cpu_ptr(mce_banks_array)[m->bank].lsb_in_status) {
+		lsb = (m->status >> 24) & 0x3f;
+
+		m->addr &= GENMASK_ULL(56, lsb);
+
+		return;
+	}
+
+	lsb = (m->addr >> 56) & 0x3f;
+
+	m->addr &= GENMASK_ULL(55, lsb);
+}
+
+#else
+static inline bool amd_filter_mce(struct mce *m) { return false; }
+static inline void smca_extract_err_addr(struct mce *m) { }
+#endif
+
+#ifdef CONFIG_X86_ANCIENT_MCE
+void intel_p5_mcheck_init(struct cpuinfo_x86 *c);
+void winchip_mcheck_init(struct cpuinfo_x86 *c);
+noinstr void pentium_machine_check(struct pt_regs *regs);
+noinstr void winchip_machine_check(struct pt_regs *regs);
+static inline void enable_p5_mce(void) { mce_p5_enabled = 1; }
+#else
+static __always_inline void intel_p5_mcheck_init(struct cpuinfo_x86 *c) {}
+static __always_inline void winchip_mcheck_init(struct cpuinfo_x86 *c) {}
+static __always_inline void enable_p5_mce(void) {}
+static __always_inline void pentium_machine_check(struct pt_regs *regs) {}
+static __always_inline void winchip_machine_check(struct pt_regs *regs) {}
+#endif
+
+noinstr u64 mce_rdmsrl(u32 msr);
+
+static __always_inline u32 mca_msr_reg(int bank, enum mca_msr reg)
+{
+	if (cpu_feature_enabled(X86_FEATURE_SMCA)) {
+		switch (reg) {
+		case MCA_CTL:	 return MSR_AMD64_SMCA_MCx_CTL(bank);
+		case MCA_ADDR:	 return MSR_AMD64_SMCA_MCx_ADDR(bank);
+		case MCA_MISC:	 return MSR_AMD64_SMCA_MCx_MISC(bank);
+		case MCA_STATUS: return MSR_AMD64_SMCA_MCx_STATUS(bank);
+		}
+	}
+
+	switch (reg) {
+	case MCA_CTL:	 return MSR_IA32_MCx_CTL(bank);
+	case MCA_ADDR:	 return MSR_IA32_MCx_ADDR(bank);
+	case MCA_MISC:	 return MSR_IA32_MCx_MISC(bank);
+	case MCA_STATUS: return MSR_IA32_MCx_STATUS(bank);
+	}
+
+	return 0;
+}
+
+extern void (*mc_poll_banks)(void);
+#endif /* __X86_MCE_INTERNAL_H__ */
diff --git a/arch/x86/kernel/cpu/mce/p5.c b/arch/x86/kernel/cpu/mce/p5.c
new file mode 100644
index 0000000000..2272ad53fc
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/p5.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * P5 specific Machine Check Exception Reporting
+ * (C) Copyright 2002 Alan Cox <alan@lxorguk.ukuu.org.uk>
+ */
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/smp.h>
+#include <linux/hardirq.h>
+
+#include <asm/processor.h>
+#include <asm/traps.h>
+#include <asm/tlbflush.h>
+#include <asm/mce.h>
+#include <asm/msr.h>
+
+#include "internal.h"
+
+/* By default disabled */
+int mce_p5_enabled __read_mostly;
+
+/* Machine check handler for Pentium class Intel CPUs: */
+noinstr void pentium_machine_check(struct pt_regs *regs)
+{
+	u32 loaddr, hi, lotype;
+
+	instrumentation_begin();
+	rdmsr(MSR_IA32_P5_MC_ADDR, loaddr, hi);
+	rdmsr(MSR_IA32_P5_MC_TYPE, lotype, hi);
+
+	pr_emerg("CPU#%d: Machine Check Exception:  0x%8X (type 0x%8X).\n",
+		 smp_processor_id(), loaddr, lotype);
+
+	if (lotype & (1<<5)) {
+		pr_emerg("CPU#%d: Possible thermal failure (CPU on fire ?).\n",
+			 smp_processor_id());
+	}
+
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
+	instrumentation_end();
+}
+
+/* Set up machine check reporting for processors with Intel style MCE: */
+void intel_p5_mcheck_init(struct cpuinfo_x86 *c)
+{
+	u32 l, h;
+
+	/* Default P5 to off as its often misconnected: */
+	if (!mce_p5_enabled)
+		return;
+
+	/* Check for MCE support: */
+	if (!cpu_has(c, X86_FEATURE_MCE))
+		return;
+
+	/* Read registers before enabling: */
+	rdmsr(MSR_IA32_P5_MC_ADDR, l, h);
+	rdmsr(MSR_IA32_P5_MC_TYPE, l, h);
+	pr_info("Intel old style machine check architecture supported.\n");
+
+	/* Enable MCE: */
+	cr4_set_bits(X86_CR4_MCE);
+	pr_info("Intel old style machine check reporting enabled on CPU#%d.\n",
+		smp_processor_id());
+}
diff --git a/arch/x86/kernel/cpu/mce/severity.c b/arch/x86/kernel/cpu/mce/severity.c
new file mode 100644
index 0000000000..c4477162c0
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/severity.c
@@ -0,0 +1,479 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * MCE grading rules.
+ * Copyright 2008, 2009 Intel Corporation.
+ *
+ * Author: Andi Kleen
+ */
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+#include <asm/mce.h>
+#include <asm/intel-family.h>
+#include <asm/traps.h>
+#include <asm/insn.h>
+#include <asm/insn-eval.h>
+
+#include "internal.h"
+
+/*
+ * Grade an mce by severity. In general the most severe ones are processed
+ * first. Since there are quite a lot of combinations test the bits in a
+ * table-driven way. The rules are simply processed in order, first
+ * match wins.
+ *
+ * Note this is only used for machine check exceptions, the corrected
+ * errors use much simpler rules. The exceptions still check for the corrected
+ * errors, but only to leave them alone for the CMCI handler (except for
+ * panic situations)
+ */
+
+enum context { IN_KERNEL = 1, IN_USER = 2, IN_KERNEL_RECOV = 3 };
+enum ser { SER_REQUIRED = 1, NO_SER = 2 };
+enum exception { EXCP_CONTEXT = 1, NO_EXCP = 2 };
+
+static struct severity {
+	u64 mask;
+	u64 result;
+	unsigned char sev;
+	unsigned char mcgmask;
+	unsigned char mcgres;
+	unsigned char ser;
+	unsigned char context;
+	unsigned char excp;
+	unsigned char covered;
+	unsigned char cpu_model;
+	unsigned char cpu_minstepping;
+	unsigned char bank_lo, bank_hi;
+	char *msg;
+} severities[] = {
+#define MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c }
+#define BANK_RANGE(l, h) .bank_lo = l, .bank_hi = h
+#define MODEL_STEPPING(m, s) .cpu_model = m, .cpu_minstepping = s
+#define  KERNEL		.context = IN_KERNEL
+#define  USER		.context = IN_USER
+#define  KERNEL_RECOV	.context = IN_KERNEL_RECOV
+#define  SER		.ser = SER_REQUIRED
+#define  NOSER		.ser = NO_SER
+#define  EXCP		.excp = EXCP_CONTEXT
+#define  NOEXCP		.excp = NO_EXCP
+#define  BITCLR(x)	.mask = x, .result = 0
+#define  BITSET(x)	.mask = x, .result = x
+#define  MCGMASK(x, y)	.mcgmask = x, .mcgres = y
+#define  MASK(x, y)	.mask = x, .result = y
+#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
+#define MCI_UC_AR (MCI_STATUS_UC|MCI_STATUS_AR)
+#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
+#define	MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
+
+	MCESEV(
+		NO, "Invalid",
+		BITCLR(MCI_STATUS_VAL)
+		),
+	MCESEV(
+		NO, "Not enabled",
+		EXCP, BITCLR(MCI_STATUS_EN)
+		),
+	MCESEV(
+		PANIC, "Processor context corrupt",
+		BITSET(MCI_STATUS_PCC)
+		),
+	/* When MCIP is not set something is very confused */
+	MCESEV(
+		PANIC, "MCIP not set in MCA handler",
+		EXCP, MCGMASK(MCG_STATUS_MCIP, 0)
+		),
+	/* Neither return not error IP -- no chance to recover -> PANIC */
+	MCESEV(
+		PANIC, "Neither restart nor error IP",
+		EXCP, MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
+		),
+	MCESEV(
+		PANIC, "In kernel and no restart IP",
+		EXCP, KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
+		),
+	MCESEV(
+		PANIC, "In kernel and no restart IP",
+		EXCP, KERNEL_RECOV, MCGMASK(MCG_STATUS_RIPV, 0)
+		),
+	MCESEV(
+		KEEP, "Corrected error",
+		NOSER, BITCLR(MCI_STATUS_UC)
+		),
+	/*
+	 * known AO MCACODs reported via MCE or CMC:
+	 *
+	 * SRAO could be signaled either via a machine check exception or
+	 * CMCI with the corresponding bit S 1 or 0. So we don't need to
+	 * check bit S for SRAO.
+	 */
+	MCESEV(
+		AO, "Action optional: memory scrubbing error",
+		SER, MASK(MCI_UC_AR|MCACOD_SCRUBMSK, MCI_STATUS_UC|MCACOD_SCRUB)
+		),
+	MCESEV(
+		AO, "Action optional: last level cache writeback error",
+		SER, MASK(MCI_UC_AR|MCACOD, MCI_STATUS_UC|MCACOD_L3WB)
+		),
+	/*
+	 * Quirk for Skylake/Cascade Lake. Patrol scrubber may be configured
+	 * to report uncorrected errors using CMCI with a special signature.
+	 * UC=0, MSCOD=0x0010, MCACOD=binary(000X 0000 1100 XXXX) reported
+	 * in one of the memory controller banks.
+	 * Set severity to "AO" for same action as normal patrol scrub error.
+	 */
+	MCESEV(
+		AO, "Uncorrected Patrol Scrub Error",
+		SER, MASK(MCI_STATUS_UC|MCI_ADDR|0xffffeff0, MCI_ADDR|0x001000c0),
+		MODEL_STEPPING(INTEL_FAM6_SKYLAKE_X, 4), BANK_RANGE(13, 18)
+	),
+
+	/* ignore OVER for UCNA */
+	MCESEV(
+		UCNA, "Uncorrected no action required",
+		SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
+		),
+	MCESEV(
+		PANIC, "Illegal combination (UCNA with AR=1)",
+		SER,
+		MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR)
+		),
+	MCESEV(
+		KEEP, "Non signaled machine check",
+		SER, BITCLR(MCI_STATUS_S)
+		),
+
+	MCESEV(
+		PANIC, "Action required with lost events",
+		SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
+		),
+
+	/* known AR MCACODs: */
+#ifdef	CONFIG_MEMORY_FAILURE
+	MCESEV(
+		KEEP, "Action required but unaffected thread is continuable",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR, MCI_UC_SAR|MCI_ADDR),
+		MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, MCG_STATUS_RIPV)
+		),
+	MCESEV(
+		AR, "Action required: data load in error recoverable area of kernel",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
+		KERNEL_RECOV
+		),
+	MCESEV(
+		AR, "Action required: data load error in a user process",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
+		USER
+		),
+	MCESEV(
+		AR, "Action required: instruction fetch error in a user process",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR),
+		USER
+		),
+	MCESEV(
+		PANIC, "Data load in unrecoverable area of kernel",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
+		KERNEL
+		),
+	MCESEV(
+		PANIC, "Instruction fetch error in kernel",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR),
+		KERNEL
+		),
+#endif
+	MCESEV(
+		PANIC, "Action required: unknown MCACOD",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
+		),
+
+	MCESEV(
+		SOME, "Action optional: unknown MCACOD",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S)
+		),
+	MCESEV(
+		SOME, "Action optional with lost events",
+		SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_S)
+		),
+
+	MCESEV(
+		PANIC, "Overflowed uncorrected",
+		BITSET(MCI_STATUS_OVER|MCI_STATUS_UC)
+		),
+	MCESEV(
+		PANIC, "Uncorrected in kernel",
+		BITSET(MCI_STATUS_UC),
+		KERNEL
+		),
+	MCESEV(
+		UC, "Uncorrected",
+		BITSET(MCI_STATUS_UC)
+		),
+	MCESEV(
+		SOME, "No match",
+		BITSET(0)
+		)	/* always matches. keep at end */
+};
+
+#define mc_recoverable(mcg) (((mcg) & (MCG_STATUS_RIPV|MCG_STATUS_EIPV)) == \
+				(MCG_STATUS_RIPV|MCG_STATUS_EIPV))
+
+static bool is_copy_from_user(struct pt_regs *regs)
+{
+	u8 insn_buf[MAX_INSN_SIZE];
+	unsigned long addr;
+	struct insn insn;
+	int ret;
+
+	if (!regs)
+		return false;
+
+	if (copy_from_kernel_nofault(insn_buf, (void *)regs->ip, MAX_INSN_SIZE))
+		return false;
+
+	ret = insn_decode_kernel(&insn, insn_buf);
+	if (ret < 0)
+		return false;
+
+	switch (insn.opcode.value) {
+	/* MOV mem,reg */
+	case 0x8A: case 0x8B:
+	/* MOVZ mem,reg */
+	case 0xB60F: case 0xB70F:
+		addr = (unsigned long)insn_get_addr_ref(&insn, regs);
+		break;
+	/* REP MOVS */
+	case 0xA4: case 0xA5:
+		addr = regs->si;
+		break;
+	default:
+		return false;
+	}
+
+	if (fault_in_kernel_space(addr))
+		return false;
+
+	current->mce_vaddr = (void __user *)addr;
+
+	return true;
+}
+
+/*
+ * If mcgstatus indicated that ip/cs on the stack were
+ * no good, then "m->cs" will be zero and we will have
+ * to assume the worst case (IN_KERNEL) as we actually
+ * have no idea what we were executing when the machine
+ * check hit.
+ * If we do have a good "m->cs" (or a faked one in the
+ * case we were executing in VM86 mode) we can use it to
+ * distinguish an exception taken in user from from one
+ * taken in the kernel.
+ */
+static noinstr int error_context(struct mce *m, struct pt_regs *regs)
+{
+	int fixup_type;
+	bool copy_user;
+
+	if ((m->cs & 3) == 3)
+		return IN_USER;
+
+	if (!mc_recoverable(m->mcgstatus))
+		return IN_KERNEL;
+
+	/* Allow instrumentation around external facilities usage. */
+	instrumentation_begin();
+	fixup_type = ex_get_fixup_type(m->ip);
+	copy_user  = is_copy_from_user(regs);
+	instrumentation_end();
+
+	switch (fixup_type) {
+	case EX_TYPE_UACCESS:
+	case EX_TYPE_COPY:
+		if (!copy_user)
+			return IN_KERNEL;
+		m->kflags |= MCE_IN_KERNEL_COPYIN;
+		fallthrough;
+
+	case EX_TYPE_FAULT_MCE_SAFE:
+	case EX_TYPE_DEFAULT_MCE_SAFE:
+		m->kflags |= MCE_IN_KERNEL_RECOV;
+		return IN_KERNEL_RECOV;
+
+	default:
+		return IN_KERNEL;
+	}
+}
+
+/* See AMD PPR(s) section Machine Check Error Handling. */
+static noinstr int mce_severity_amd(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
+{
+	char *panic_msg = NULL;
+	int ret;
+
+	/*
+	 * Default return value: Action required, the error must be handled
+	 * immediately.
+	 */
+	ret = MCE_AR_SEVERITY;
+
+	/* Processor Context Corrupt, no need to fumble too much, die! */
+	if (m->status & MCI_STATUS_PCC) {
+		panic_msg = "Processor Context Corrupt";
+		ret = MCE_PANIC_SEVERITY;
+		goto out;
+	}
+
+	if (m->status & MCI_STATUS_DEFERRED) {
+		ret = MCE_DEFERRED_SEVERITY;
+		goto out;
+	}
+
+	/*
+	 * If the UC bit is not set, the system either corrected or deferred
+	 * the error. No action will be required after logging the error.
+	 */
+	if (!(m->status & MCI_STATUS_UC)) {
+		ret = MCE_KEEP_SEVERITY;
+		goto out;
+	}
+
+	/*
+	 * On MCA overflow, without the MCA overflow recovery feature the
+	 * system will not be able to recover, panic.
+	 */
+	if ((m->status & MCI_STATUS_OVER) && !mce_flags.overflow_recov) {
+		panic_msg = "Overflowed uncorrected error without MCA Overflow Recovery";
+		ret = MCE_PANIC_SEVERITY;
+		goto out;
+	}
+
+	if (!mce_flags.succor) {
+		panic_msg = "Uncorrected error without MCA Recovery";
+		ret = MCE_PANIC_SEVERITY;
+		goto out;
+	}
+
+	if (error_context(m, regs) == IN_KERNEL) {
+		panic_msg = "Uncorrected unrecoverable error in kernel context";
+		ret = MCE_PANIC_SEVERITY;
+	}
+
+out:
+	if (msg && panic_msg)
+		*msg = panic_msg;
+
+	return ret;
+}
+
+static noinstr int mce_severity_intel(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
+{
+	enum exception excp = (is_excp ? EXCP_CONTEXT : NO_EXCP);
+	enum context ctx = error_context(m, regs);
+	struct severity *s;
+
+	for (s = severities;; s++) {
+		if ((m->status & s->mask) != s->result)
+			continue;
+		if ((m->mcgstatus & s->mcgmask) != s->mcgres)
+			continue;
+		if (s->ser == SER_REQUIRED && !mca_cfg.ser)
+			continue;
+		if (s->ser == NO_SER && mca_cfg.ser)
+			continue;
+		if (s->context && ctx != s->context)
+			continue;
+		if (s->excp && excp != s->excp)
+			continue;
+		if (s->cpu_model && boot_cpu_data.x86_model != s->cpu_model)
+			continue;
+		if (s->cpu_minstepping && boot_cpu_data.x86_stepping < s->cpu_minstepping)
+			continue;
+		if (s->bank_lo && (m->bank < s->bank_lo || m->bank > s->bank_hi))
+			continue;
+		if (msg)
+			*msg = s->msg;
+		s->covered = 1;
+
+		return s->sev;
+	}
+}
+
+int noinstr mce_severity(struct mce *m, struct pt_regs *regs, char **msg, bool is_excp)
+{
+	if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD ||
+	    boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
+		return mce_severity_amd(m, regs, msg, is_excp);
+	else
+		return mce_severity_intel(m, regs, msg, is_excp);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static void *s_start(struct seq_file *f, loff_t *pos)
+{
+	if (*pos >= ARRAY_SIZE(severities))
+		return NULL;
+	return &severities[*pos];
+}
+
+static void *s_next(struct seq_file *f, void *data, loff_t *pos)
+{
+	if (++(*pos) >= ARRAY_SIZE(severities))
+		return NULL;
+	return &severities[*pos];
+}
+
+static void s_stop(struct seq_file *f, void *data)
+{
+}
+
+static int s_show(struct seq_file *f, void *data)
+{
+	struct severity *ser = data;
+	seq_printf(f, "%d\t%s\n", ser->covered, ser->msg);
+	return 0;
+}
+
+static const struct seq_operations severities_seq_ops = {
+	.start	= s_start,
+	.next	= s_next,
+	.stop	= s_stop,
+	.show	= s_show,
+};
+
+static int severities_coverage_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &severities_seq_ops);
+}
+
+static ssize_t severities_coverage_write(struct file *file,
+					 const char __user *ubuf,
+					 size_t count, loff_t *ppos)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(severities); i++)
+		severities[i].covered = 0;
+	return count;
+}
+
+static const struct file_operations severities_coverage_fops = {
+	.open		= severities_coverage_open,
+	.release	= seq_release,
+	.read		= seq_read,
+	.write		= severities_coverage_write,
+	.llseek		= seq_lseek,
+};
+
+static int __init severities_debugfs_init(void)
+{
+	struct dentry *dmce;
+
+	dmce = mce_get_debugfs_dir();
+
+	debugfs_create_file("severities-coverage", 0444, dmce, NULL,
+			    &severities_coverage_fops);
+	return 0;
+}
+late_initcall(severities_debugfs_init);
+#endif /* CONFIG_DEBUG_FS */
diff --git a/arch/x86/kernel/cpu/mce/threshold.c b/arch/x86/kernel/cpu/mce/threshold.c
new file mode 100644
index 0000000000..ef4e7bb5fd
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/threshold.c
@@ -0,0 +1,31 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Common corrected MCE threshold handler code:
+ */
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+
+#include <asm/irq_vectors.h>
+#include <asm/traps.h>
+#include <asm/apic.h>
+#include <asm/mce.h>
+#include <asm/trace/irq_vectors.h>
+
+#include "internal.h"
+
+static void default_threshold_interrupt(void)
+{
+	pr_err("Unexpected threshold interrupt at vector %x\n",
+		THRESHOLD_APIC_VECTOR);
+}
+
+void (*mce_threshold_vector)(void) = default_threshold_interrupt;
+
+DEFINE_IDTENTRY_SYSVEC(sysvec_threshold)
+{
+	trace_threshold_apic_entry(THRESHOLD_APIC_VECTOR);
+	inc_irq_stat(irq_threshold_count);
+	mce_threshold_vector();
+	trace_threshold_apic_exit(THRESHOLD_APIC_VECTOR);
+	apic_eoi();
+}
diff --git a/arch/x86/kernel/cpu/mce/winchip.c b/arch/x86/kernel/cpu/mce/winchip.c
new file mode 100644
index 0000000000..6c99f29419
--- /dev/null
+++ b/arch/x86/kernel/cpu/mce/winchip.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IDT Winchip specific Machine Check Exception Reporting
+ * (C) Copyright 2002 Alan Cox <alan@lxorguk.ukuu.org.uk>
+ */
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/hardirq.h>
+
+#include <asm/processor.h>
+#include <asm/traps.h>
+#include <asm/tlbflush.h>
+#include <asm/mce.h>
+#include <asm/msr.h>
+
+#include "internal.h"
+
+/* Machine check handler for WinChip C6: */
+noinstr void winchip_machine_check(struct pt_regs *regs)
+{
+	instrumentation_begin();
+	pr_emerg("CPU0: Machine Check Exception.\n");
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
+	instrumentation_end();
+}
+
+/* Set up machine check reporting on the Winchip C6 series */
+void winchip_mcheck_init(struct cpuinfo_x86 *c)
+{
+	u32 lo, hi;
+
+	rdmsr(MSR_IDT_FCR1, lo, hi);
+	lo |= (1<<2);	/* Enable EIERRINT (int 18 MCE) */
+	lo &= ~(1<<4);	/* Enable MCE */
+	wrmsr(MSR_IDT_FCR1, lo, hi);
+
+	cr4_set_bits(X86_CR4_MCE);
+
+	pr_info("Winchip machine check reporting enabled on CPU#0.\n");
+}