1 files changed, 771 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/mce.c b/arch/powerpc/kernel/mce.c
new file mode 100644
index 0000000000..219f28637a
--- /dev/null
+++ b/arch/powerpc/kernel/mce.c
@@ -0,0 +1,771 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Machine check exception handling.
+ *
+ * Copyright 2013 IBM Corporation
+ * Author: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
+ */
+
+#undef DEBUG
+#define pr_fmt(fmt) "mce: " fmt
+
+#include <linux/hardirq.h>
+#include <linux/types.h>
+#include <linux/ptrace.h>
+#include <linux/percpu.h>
+#include <linux/export.h>
+#include <linux/irq_work.h>
+#include <linux/extable.h>
+#include <linux/ftrace.h>
+#include <linux/memblock.h>
+#include <linux/of.h>
+
+#include <asm/interrupt.h>
+#include <asm/machdep.h>
+#include <asm/mce.h>
+#include <asm/nmi.h>
+
+#include "setup.h"
+
+static void machine_check_ue_event(struct machine_check_event *evt);
+static void machine_process_ue_event(struct work_struct *work);
+
+static DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
+
+static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
+
+int mce_register_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_register(&mce_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(mce_register_notifier);
+
+int mce_unregister_notifier(struct notifier_block *nb)
+{
+	return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
+}
+EXPORT_SYMBOL_GPL(mce_unregister_notifier);
+
+static void mce_set_error_info(struct machine_check_event *mce,
+			       struct mce_error_info *mce_err)
+{
+	mce->error_type = mce_err->error_type;
+	switch (mce_err->error_type) {
+	case MCE_ERROR_TYPE_UE:
+		mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type;
+		break;
+	case MCE_ERROR_TYPE_SLB:
+		mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type;
+		break;
+	case MCE_ERROR_TYPE_ERAT:
+		mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type;
+		break;
+	case MCE_ERROR_TYPE_TLB:
+		mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type;
+		break;
+	case MCE_ERROR_TYPE_USER:
+		mce->u.user_error.user_error_type = mce_err->u.user_error_type;
+		break;
+	case MCE_ERROR_TYPE_RA:
+		mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type;
+		break;
+	case MCE_ERROR_TYPE_LINK:
+		mce->u.link_error.link_error_type = mce_err->u.link_error_type;
+		break;
+	case MCE_ERROR_TYPE_UNKNOWN:
+	default:
+		break;
+	}
+}
+
+void mce_irq_work_queue(void)
+{
+	/* Raise decrementer interrupt */
+	arch_irq_work_raise();
+	set_mce_pending_irq_work();
+}
+
+/*
+ * Decode and save high level MCE information into per cpu buffer which
+ * is an array of machine_check_event structure.
+ */
+void save_mce_event(struct pt_regs *regs, long handled,
+		    struct mce_error_info *mce_err,
+		    uint64_t nip, uint64_t addr, uint64_t phys_addr)
+{
+	int index = local_paca->mce_info->mce_nest_count++;
+	struct machine_check_event *mce;
+
+	mce = &local_paca->mce_info->mce_event[index];
+	/*
+	 * Return if we don't have enough space to log mce event.
+	 * mce_nest_count may go beyond MAX_MC_EVT but that's ok,
+	 * the check below will stop buffer overrun.
+	 */
+	if (index >= MAX_MC_EVT)
+		return;
+
+	/* Populate generic machine check info */
+	mce->version = MCE_V1;
+	mce->srr0 = nip;
+	mce->srr1 = regs->msr;
+	mce->gpr3 = regs->gpr[3];
+	mce->in_use = 1;
+	mce->cpu = get_paca()->paca_index;
+
+	/* Mark it recovered if we have handled it and MSR(RI=1). */
+	if (handled && (regs->msr & MSR_RI))
+		mce->disposition = MCE_DISPOSITION_RECOVERED;
+	else
+		mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;
+
+	mce->initiator = mce_err->initiator;
+	mce->severity = mce_err->severity;
+	mce->sync_error = mce_err->sync_error;
+	mce->error_class = mce_err->error_class;
+
+	/*
+	 * Populate the mce error_type and type-specific error_type.
+	 */
+	mce_set_error_info(mce, mce_err);
+	if (mce->error_type == MCE_ERROR_TYPE_UE)
+		mce->u.ue_error.ignore_event = mce_err->ignore_event;
+
+	/*
+	 * Raise irq work, So that we don't miss to log the error for
+	 * unrecoverable errors.
+	 */
+	if (mce->disposition == MCE_DISPOSITION_NOT_RECOVERED)
+		mce_irq_work_queue();
+
+	if (!addr)
+		return;
+
+	if (mce->error_type == MCE_ERROR_TYPE_TLB) {
+		mce->u.tlb_error.effective_address_provided = true;
+		mce->u.tlb_error.effective_address = addr;
+	} else if (mce->error_type == MCE_ERROR_TYPE_SLB) {
+		mce->u.slb_error.effective_address_provided = true;
+		mce->u.slb_error.effective_address = addr;
+	} else if (mce->error_type == MCE_ERROR_TYPE_ERAT) {
+		mce->u.erat_error.effective_address_provided = true;
+		mce->u.erat_error.effective_address = addr;
+	} else if (mce->error_type == MCE_ERROR_TYPE_USER) {
+		mce->u.user_error.effective_address_provided = true;
+		mce->u.user_error.effective_address = addr;
+	} else if (mce->error_type == MCE_ERROR_TYPE_RA) {
+		mce->u.ra_error.effective_address_provided = true;
+		mce->u.ra_error.effective_address = addr;
+	} else if (mce->error_type == MCE_ERROR_TYPE_LINK) {
+		mce->u.link_error.effective_address_provided = true;
+		mce->u.link_error.effective_address = addr;
+	} else if (mce->error_type == MCE_ERROR_TYPE_UE) {
+		mce->u.ue_error.effective_address_provided = true;
+		mce->u.ue_error.effective_address = addr;
+		if (phys_addr != ULONG_MAX) {
+			mce->u.ue_error.physical_address_provided = true;
+			mce->u.ue_error.physical_address = phys_addr;
+			machine_check_ue_event(mce);
+		}
+	}
+	return;
+}
+
+/*
+ * get_mce_event:
+ *	mce	Pointer to machine_check_event structure to be filled.
+ *	release Flag to indicate whether to free the event slot or not.
+ *		0 <= do not release the mce event. Caller will invoke
+ *		     release_mce_event() once event has been consumed.
+ *		1 <= release the slot.
+ *
+ *	return	1 = success
+ *		0 = failure
+ *
+ * get_mce_event() will be called by platform specific machine check
+ * handle routine and in KVM.
+ * When we call get_mce_event(), we are still in interrupt context and
+ * preemption will not be scheduled until ret_from_expect() routine
+ * is called.
+ */
+int get_mce_event(struct machine_check_event *mce, bool release)
+{
+	int index = local_paca->mce_info->mce_nest_count - 1;
+	struct machine_check_event *mc_evt;
+	int ret = 0;
+
+	/* Sanity check */
+	if (index < 0)
+		return ret;
+
+	/* Check if we have MCE info to process. */
+	if (index < MAX_MC_EVT) {
+		mc_evt = &local_paca->mce_info->mce_event[index];
+		/* Copy the event structure and release the original */
+		if (mce)
+			*mce = *mc_evt;
+		if (release)
+			mc_evt->in_use = 0;
+		ret = 1;
+	}
+	/* Decrement the count to free the slot. */
+	if (release)
+		local_paca->mce_info->mce_nest_count--;
+
+	return ret;
+}
+
+void release_mce_event(void)
+{
+	get_mce_event(NULL, true);
+}
+
+static void machine_check_ue_work(void)
+{
+	schedule_work(&mce_ue_event_work);
+}
+
+/*
+ * Queue up the MCE event which then can be handled later.
+ */
+static void machine_check_ue_event(struct machine_check_event *evt)
+{
+	int index;
+
+	index = local_paca->mce_info->mce_ue_count++;
+	/* If queue is full, just return for now. */
+	if (index >= MAX_MC_EVT) {
+		local_paca->mce_info->mce_ue_count--;
+		return;
+	}
+	memcpy(&local_paca->mce_info->mce_ue_event_queue[index],
+	       evt, sizeof(*evt));
+}
+
+/*
+ * Queue up the MCE event which then can be handled later.
+ */
+void machine_check_queue_event(void)
+{
+	int index;
+	struct machine_check_event evt;
+
+	if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
+		return;
+
+	index = local_paca->mce_info->mce_queue_count++;
+	/* If queue is full, just return for now. */
+	if (index >= MAX_MC_EVT) {
+		local_paca->mce_info->mce_queue_count--;
+		return;
+	}
+	memcpy(&local_paca->mce_info->mce_event_queue[index],
+	       &evt, sizeof(evt));
+
+	mce_irq_work_queue();
+}
+
+void mce_common_process_ue(struct pt_regs *regs,
+			   struct mce_error_info *mce_err)
+{
+	const struct exception_table_entry *entry;
+
+	entry = search_kernel_exception_table(regs->nip);
+	if (entry) {
+		mce_err->ignore_event = true;
+		regs_set_return_ip(regs, extable_fixup(entry));
+	}
+}
+
+/*
+ * process pending MCE event from the mce event queue. This function will be
+ * called during syscall exit.
+ */
+static void machine_process_ue_event(struct work_struct *work)
+{
+	int index;
+	struct machine_check_event *evt;
+
+	while (local_paca->mce_info->mce_ue_count > 0) {
+		index = local_paca->mce_info->mce_ue_count - 1;
+		evt = &local_paca->mce_info->mce_ue_event_queue[index];
+		blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
+#ifdef CONFIG_MEMORY_FAILURE
+		/*
+		 * This should probably queued elsewhere, but
+		 * oh! well
+		 *
+		 * Don't report this machine check because the caller has a
+		 * asked us to ignore the event, it has a fixup handler which
+		 * will do the appropriate error handling and reporting.
+		 */
+		if (evt->error_type == MCE_ERROR_TYPE_UE) {
+			if (evt->u.ue_error.ignore_event) {
+				local_paca->mce_info->mce_ue_count--;
+				continue;
+			}
+
+			if (evt->u.ue_error.physical_address_provided) {
+				unsigned long pfn;
+
+				pfn = evt->u.ue_error.physical_address >>
+					PAGE_SHIFT;
+				memory_failure(pfn, 0);
+			} else
+				pr_warn("Failed to identify bad address from "
+					"where the uncorrectable error (UE) "
+					"was generated\n");
+		}
+#endif
+		local_paca->mce_info->mce_ue_count--;
+	}
+}
+/*
+ * process pending MCE event from the mce event queue. This function will be
+ * called during syscall exit.
+ */
+static void machine_check_process_queued_event(void)
+{
+	int index;
+	struct machine_check_event *evt;
+
+	add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
+
+	/*
+	 * For now just print it to console.
+	 * TODO: log this error event to FSP or nvram.
+	 */
+	while (local_paca->mce_info->mce_queue_count > 0) {
+		index = local_paca->mce_info->mce_queue_count - 1;
+		evt = &local_paca->mce_info->mce_event_queue[index];
+
+		if (evt->error_type == MCE_ERROR_TYPE_UE &&
+		    evt->u.ue_error.ignore_event) {
+			local_paca->mce_info->mce_queue_count--;
+			continue;
+		}
+		machine_check_print_event_info(evt, false, false);
+		local_paca->mce_info->mce_queue_count--;
+	}
+}
+
+void set_mce_pending_irq_work(void)
+{
+	local_paca->mce_pending_irq_work = 1;
+}
+
+void clear_mce_pending_irq_work(void)
+{
+	local_paca->mce_pending_irq_work = 0;
+}
+
+void mce_run_irq_context_handlers(void)
+{
+	if (unlikely(local_paca->mce_pending_irq_work)) {
+		if (ppc_md.machine_check_log_err)
+			ppc_md.machine_check_log_err();
+		machine_check_process_queued_event();
+		machine_check_ue_work();
+		clear_mce_pending_irq_work();
+	}
+}
+
+void machine_check_print_event_info(struct machine_check_event *evt,
+				    bool user_mode, bool in_guest)
+{
+	const char *level, *sevstr, *subtype, *err_type, *initiator;
+	uint64_t ea = 0, pa = 0;
+	int n = 0;
+	char dar_str[50];
+	char pa_str[50];
+	static const char *mc_ue_types[] = {
+		"Indeterminate",
+		"Instruction fetch",
+		"Page table walk ifetch",
+		"Load/Store",
+		"Page table walk Load/Store",
+	};
+	static const char *mc_slb_types[] = {
+		"Indeterminate",
+		"Parity",
+		"Multihit",
+	};
+	static const char *mc_erat_types[] = {
+		"Indeterminate",
+		"Parity",
+		"Multihit",
+	};
+	static const char *mc_tlb_types[] = {
+		"Indeterminate",
+		"Parity",
+		"Multihit",
+	};
+	static const char *mc_user_types[] = {
+		"Indeterminate",
+		"tlbie(l) invalid",
+		"scv invalid",
+	};
+	static const char *mc_ra_types[] = {
+		"Indeterminate",
+		"Instruction fetch (bad)",
+		"Instruction fetch (foreign/control memory)",
+		"Page table walk ifetch (bad)",
+		"Page table walk ifetch (foreign/control memory)",
+		"Load (bad)",
+		"Store (bad)",
+		"Page table walk Load/Store (bad)",
+		"Page table walk Load/Store (foreign/control memory)",
+		"Load/Store (foreign/control memory)",
+	};
+	static const char *mc_link_types[] = {
+		"Indeterminate",
+		"Instruction fetch (timeout)",
+		"Page table walk ifetch (timeout)",
+		"Load (timeout)",
+		"Store (timeout)",
+		"Page table walk Load/Store (timeout)",
+	};
+	static const char *mc_error_class[] = {
+		"Unknown",
+		"Hardware error",
+		"Probable Hardware error (some chance of software cause)",
+		"Software error",
+		"Probable Software error (some chance of hardware cause)",
+	};
+
+	/* Print things out */
+	if (evt->version != MCE_V1) {
+		pr_err("Machine Check Exception, Unknown event version %d !\n",
+		       evt->version);
+		return;
+	}
+	switch (evt->severity) {
+	case MCE_SEV_NO_ERROR:
+		level = KERN_INFO;
+		sevstr = "Harmless";
+		break;
+	case MCE_SEV_WARNING:
+		level = KERN_WARNING;
+		sevstr = "Warning";
+		break;
+	case MCE_SEV_SEVERE:
+		level = KERN_ERR;
+		sevstr = "Severe";
+		break;
+	case MCE_SEV_FATAL:
+	default:
+		level = KERN_ERR;
+		sevstr = "Fatal";
+		break;
+	}
+
+	switch(evt->initiator) {
+	case MCE_INITIATOR_CPU:
+		initiator = "CPU";
+		break;
+	case MCE_INITIATOR_PCI:
+		initiator = "PCI";
+		break;
+	case MCE_INITIATOR_ISA:
+		initiator = "ISA";
+		break;
+	case MCE_INITIATOR_MEMORY:
+		initiator = "Memory";
+		break;
+	case MCE_INITIATOR_POWERMGM:
+		initiator = "Power Management";
+		break;
+	case MCE_INITIATOR_UNKNOWN:
+	default:
+		initiator = "Unknown";
+		break;
+	}
+
+	switch (evt->error_type) {
+	case MCE_ERROR_TYPE_UE:
+		err_type = "UE";
+		subtype = evt->u.ue_error.ue_error_type <
+			ARRAY_SIZE(mc_ue_types) ?
+			mc_ue_types[evt->u.ue_error.ue_error_type]
+			: "Unknown";
+		if (evt->u.ue_error.effective_address_provided)
+			ea = evt->u.ue_error.effective_address;
+		if (evt->u.ue_error.physical_address_provided)
+			pa = evt->u.ue_error.physical_address;
+		break;
+	case MCE_ERROR_TYPE_SLB:
+		err_type = "SLB";
+		subtype = evt->u.slb_error.slb_error_type <
+			ARRAY_SIZE(mc_slb_types) ?
+			mc_slb_types[evt->u.slb_error.slb_error_type]
+			: "Unknown";
+		if (evt->u.slb_error.effective_address_provided)
+			ea = evt->u.slb_error.effective_address;
+		break;
+	case MCE_ERROR_TYPE_ERAT:
+		err_type = "ERAT";
+		subtype = evt->u.erat_error.erat_error_type <
+			ARRAY_SIZE(mc_erat_types) ?
+			mc_erat_types[evt->u.erat_error.erat_error_type]
+			: "Unknown";
+		if (evt->u.erat_error.effective_address_provided)
+			ea = evt->u.erat_error.effective_address;
+		break;
+	case MCE_ERROR_TYPE_TLB:
+		err_type = "TLB";
+		subtype = evt->u.tlb_error.tlb_error_type <
+			ARRAY_SIZE(mc_tlb_types) ?
+			mc_tlb_types[evt->u.tlb_error.tlb_error_type]
+			: "Unknown";
+		if (evt->u.tlb_error.effective_address_provided)
+			ea = evt->u.tlb_error.effective_address;
+		break;
+	case MCE_ERROR_TYPE_USER:
+		err_type = "User";
+		subtype = evt->u.user_error.user_error_type <
+			ARRAY_SIZE(mc_user_types) ?
+			mc_user_types[evt->u.user_error.user_error_type]
+			: "Unknown";
+		if (evt->u.user_error.effective_address_provided)
+			ea = evt->u.user_error.effective_address;
+		break;
+	case MCE_ERROR_TYPE_RA:
+		err_type = "Real address";
+		subtype = evt->u.ra_error.ra_error_type <
+			ARRAY_SIZE(mc_ra_types) ?
+			mc_ra_types[evt->u.ra_error.ra_error_type]
+			: "Unknown";
+		if (evt->u.ra_error.effective_address_provided)
+			ea = evt->u.ra_error.effective_address;
+		break;
+	case MCE_ERROR_TYPE_LINK:
+		err_type = "Link";
+		subtype = evt->u.link_error.link_error_type <
+			ARRAY_SIZE(mc_link_types) ?
+			mc_link_types[evt->u.link_error.link_error_type]
+			: "Unknown";
+		if (evt->u.link_error.effective_address_provided)
+			ea = evt->u.link_error.effective_address;
+		break;
+	case MCE_ERROR_TYPE_DCACHE:
+		err_type = "D-Cache";
+		subtype = "Unknown";
+		break;
+	case MCE_ERROR_TYPE_ICACHE:
+		err_type = "I-Cache";
+		subtype = "Unknown";
+		break;
+	default:
+	case MCE_ERROR_TYPE_UNKNOWN:
+		err_type = "Unknown";
+		subtype = "";
+		break;
+	}
+
+	dar_str[0] = pa_str[0] = '\0';
+	if (ea && evt->srr0 != ea) {
+		/* Load/Store address */
+		n = sprintf(dar_str, "DAR: %016llx ", ea);
+		if (pa)
+			sprintf(dar_str + n, "paddr: %016llx ", pa);
+	} else if (pa) {
+		sprintf(pa_str, " paddr: %016llx", pa);
+	}
+
+	printk("%sMCE: CPU%d: machine check (%s) %s %s %s %s[%s]\n",
+		level, evt->cpu, sevstr, in_guest ? "Guest" : "",
+		err_type, subtype, dar_str,
+		evt->disposition == MCE_DISPOSITION_RECOVERED ?
+		"Recovered" : "Not recovered");
+
+	if (in_guest || user_mode) {
+		printk("%sMCE: CPU%d: PID: %d Comm: %s %sNIP: [%016llx]%s\n",
+			level, evt->cpu, current->pid, current->comm,
+			in_guest ? "Guest " : "", evt->srr0, pa_str);
+	} else {
+		printk("%sMCE: CPU%d: NIP: [%016llx] %pS%s\n",
+			level, evt->cpu, evt->srr0, (void *)evt->srr0, pa_str);
+	}
+
+	printk("%sMCE: CPU%d: Initiator %s\n", level, evt->cpu, initiator);
+
+	subtype = evt->error_class < ARRAY_SIZE(mc_error_class) ?
+		mc_error_class[evt->error_class] : "Unknown";
+	printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);
+
+#ifdef CONFIG_PPC_64S_HASH_MMU
+	/* Display faulty slb contents for SLB errors. */
+	if (evt->error_type == MCE_ERROR_TYPE_SLB && !in_guest)
+		slb_dump_contents(local_paca->mce_faulty_slbs);
+#endif
+}
+EXPORT_SYMBOL_GPL(machine_check_print_event_info);
+
+/*
+ * This function is called in real mode. Strictly no printk's please.
+ *
+ * regs->nip and regs->msr contains srr0 and ssr1.
+ */
+DEFINE_INTERRUPT_HANDLER_NMI(machine_check_early)
+{
+	long handled = 0;
+
+	hv_nmi_check_nonrecoverable(regs);
+
+	/*
+	 * See if platform is capable of handling machine check.
+	 */
+	if (ppc_md.machine_check_early)
+		handled = ppc_md.machine_check_early(regs);
+
+	return handled;
+}
+
+/* Possible meanings for HMER_DEBUG_TRIG bit being set on POWER9 */
+static enum {
+	DTRIG_UNKNOWN,
+	DTRIG_VECTOR_CI,	/* need to emulate vector CI load instr */
+	DTRIG_SUSPEND_ESCAPE,	/* need to escape from TM suspend mode */
+} hmer_debug_trig_function;
+
+static int init_debug_trig_function(void)
+{
+	int pvr;
+	struct device_node *cpun;
+	struct property *prop = NULL;
+	const char *str;
+
+	/* First look in the device tree */
+	preempt_disable();
+	cpun = of_get_cpu_node(smp_processor_id(), NULL);
+	if (cpun) {
+		of_property_for_each_string(cpun, "ibm,hmi-special-triggers",
+					    prop, str) {
+			if (strcmp(str, "bit17-vector-ci-load") == 0)
+				hmer_debug_trig_function = DTRIG_VECTOR_CI;
+			else if (strcmp(str, "bit17-tm-suspend-escape") == 0)
+				hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
+		}
+		of_node_put(cpun);
+	}
+	preempt_enable();
+
+	/* If we found the property, don't look at PVR */
+	if (prop)
+		goto out;
+
+	pvr = mfspr(SPRN_PVR);
+	/* Check for POWER9 Nimbus (scale-out) */
+	if ((PVR_VER(pvr) == PVR_POWER9) && (pvr & 0xe000) == 0) {
+		/* DD2.2 and later */
+		if ((pvr & 0xfff) >= 0x202)
+			hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
+		/* DD2.0 and DD2.1 - used for vector CI load emulation */
+		else if ((pvr & 0xfff) >= 0x200)
+			hmer_debug_trig_function = DTRIG_VECTOR_CI;
+	}
+
+ out:
+	switch (hmer_debug_trig_function) {
+	case DTRIG_VECTOR_CI:
+		pr_debug("HMI debug trigger used for vector CI load\n");
+		break;
+	case DTRIG_SUSPEND_ESCAPE:
+		pr_debug("HMI debug trigger used for TM suspend escape\n");
+		break;
+	default:
+		break;
+	}
+	return 0;
+}
+__initcall(init_debug_trig_function);
+
+/*
+ * Handle HMIs that occur as a result of a debug trigger.
+ * Return values:
+ * -1 means this is not a HMI cause that we know about
+ *  0 means no further handling is required
+ *  1 means further handling is required
+ */
+long hmi_handle_debugtrig(struct pt_regs *regs)
+{
+	unsigned long hmer = mfspr(SPRN_HMER);
+	long ret = 0;
+
+	/* HMER_DEBUG_TRIG bit is used for various workarounds on P9 */
+	if (!((hmer & HMER_DEBUG_TRIG)
+	      && hmer_debug_trig_function != DTRIG_UNKNOWN))
+		return -1;
+		
+	hmer &= ~HMER_DEBUG_TRIG;
+	/* HMER is a write-AND register */
+	mtspr(SPRN_HMER, ~HMER_DEBUG_TRIG);
+
+	switch (hmer_debug_trig_function) {
+	case DTRIG_VECTOR_CI:
+		/*
+		 * Now to avoid problems with soft-disable we
+		 * only do the emulation if we are coming from
+		 * host user space
+		 */
+		if (regs && user_mode(regs))
+			ret = local_paca->hmi_p9_special_emu = 1;
+
+		break;
+
+	default:
+		break;
+	}
+
+	/*
+	 * See if any other HMI causes remain to be handled
+	 */
+	if (hmer & mfspr(SPRN_HMEER))
+		return -1;
+
+	return ret;
+}
+
+/*
+ * Return values:
+ */
+DEFINE_INTERRUPT_HANDLER_NMI(hmi_exception_realmode)
+{	
+	int ret;
+
+	local_paca->hmi_irqs++;
+
+	ret = hmi_handle_debugtrig(regs);
+	if (ret >= 0)
+		return ret;
+
+	wait_for_subcore_guest_exit();
+
+	if (ppc_md.hmi_exception_early)
+		ppc_md.hmi_exception_early(regs);
+
+	wait_for_tb_resync();
+
+	return 1;
+}
+
+void __init mce_init(void)
+{
+	struct mce_info *mce_info;
+	u64 limit;
+	int i;
+
+	limit = min(ppc64_bolted_size(), ppc64_rma_size);
+	for_each_possible_cpu(i) {
+		mce_info = memblock_alloc_try_nid(sizeof(*mce_info),
+						  __alignof__(*mce_info),
+						  MEMBLOCK_LOW_LIMIT,
+						  limit, early_cpu_to_node(i));
+		if (!mce_info)
+			goto err;
+		paca_ptrs[i]->mce_info = mce_info;
+	}
+	return;
+err:
+	panic("Failed to allocate memory for MCE event data\n");
+}