// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2001 Dave Engebretsen IBM Corporation
 */

#include <linux/sched.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/fs.h>
#include <linux/reboot.h>
#include <linux/irq_work.h>

#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/firmware.h>
#include <asm/mce.h>

#include "pseries.h"

static unsigned char ras_log_buf[RTAS_ERROR_LOG_MAX];
static DEFINE_SPINLOCK(ras_log_buf_lock);

static int ras_check_exception_token;

static void mce_process_errlog_event(struct irq_work *work);
static struct irq_work mce_errlog_process_work = {
        .func = mce_process_errlog_event,
};

#define EPOW_SENSOR_TOKEN       9
#define EPOW_SENSOR_INDEX       0

/* EPOW events counter variable */
static int num_epow_events;

static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id);
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
static irqreturn_t ras_error_interrupt(int irq, void *dev_id);

/* RTAS pseries MCE errorlog section. */
struct pseries_mc_errorlog {
        __be32  fru_id;
        __be32  proc_id;
        u8      error_type;
        /*
         * sub_err_type (1 byte). Bit fields depends on error_type
         *
         *   MSB0
         *   |
         *   V
         *   01234567
         *   XXXXXXXX
         *
         * For error_type == MC_ERROR_TYPE_UE
         *   XXXXXXXX
         *   X          1: Permanent or Transient UE.
         *    X         1: Effective address provided.
         *     X        1: Logical address provided.
         *      XX      2: Reserved.
         *        XXX   3: Type of UE error.
         *
         * For error_type != MC_ERROR_TYPE_UE
         *   XXXXXXXX
         *   X          1: Effective address provided.
         *    XXXXX     5: Reserved.
         *         XX   2: Type of SLB/ERAT/TLB error.
         */
        u8      sub_err_type;
        u8      reserved_1[6];
        __be64  effective_address;
        __be64  logical_address;
} __packed;

/* RTAS pseries MCE error types */
#define MC_ERROR_TYPE_UE                0x00
#define MC_ERROR_TYPE_SLB               0x01
#define MC_ERROR_TYPE_ERAT              0x02
#define MC_ERROR_TYPE_TLB               0x04
#define MC_ERROR_TYPE_D_CACHE           0x05
#define MC_ERROR_TYPE_I_CACHE           0x07

/* RTAS pseries MCE error sub types */
#define MC_ERROR_UE_INDETERMINATE               0
#define MC_ERROR_UE_IFETCH                      1
#define MC_ERROR_UE_PAGE_TABLE_WALK_IFETCH      2
#define MC_ERROR_UE_LOAD_STORE                  3
#define MC_ERROR_UE_PAGE_TABLE_WALK_LOAD_STORE  4

#define MC_ERROR_SLB_PARITY             0
#define MC_ERROR_SLB_MULTIHIT           1
#define MC_ERROR_SLB_INDETERMINATE      2

#define MC_ERROR_ERAT_PARITY            1
#define MC_ERROR_ERAT_MULTIHIT          2
#define MC_ERROR_ERAT_INDETERMINATE     3

#define MC_ERROR_TLB_PARITY             1
#define MC_ERROR_TLB_MULTIHIT           2
#define MC_ERROR_TLB_INDETERMINATE      3

static inline u8 rtas_mc_error_sub_type(const struct pseries_mc_errorlog *mlog)
{
        switch (mlog->error_type) {
        case    MC_ERROR_TYPE_UE:
                return (mlog->sub_err_type & 0x07);
        case    MC_ERROR_TYPE_SLB:
        case    MC_ERROR_TYPE_ERAT:
        case    MC_ERROR_TYPE_TLB:
                return (mlog->sub_err_type & 0x03);
        default:
                return 0;
        }
}

static
inline u64 rtas_mc_get_effective_addr(const struct pseries_mc_errorlog *mlog)
{
        __be64 addr = 0;

        switch (mlog->error_type) {
        case    MC_ERROR_TYPE_UE:
                if (mlog->sub_err_type & 0x40)
                        addr = mlog->effective_address;
                break;
        case    MC_ERROR_TYPE_SLB:
        case    MC_ERROR_TYPE_ERAT:
        case    MC_ERROR_TYPE_TLB:
                if (mlog->sub_err_type & 0x80)
                        addr = mlog->effective_address;
        default:
                break;
        }
        return be64_to_cpu(addr);
}

/*
 * Enable the hotplug interrupt late because processing them may touch other
 * devices or systems (e.g. hugepages) that have not been initialized at the
 * subsys stage.
 */
int __init init_ras_hotplug_IRQ(void)
{
        struct device_node *np;

        /* Hotplug Events */
        np = of_find_node_by_path("/event-sources/hot-plug-events");
        if (np != NULL) {
                if (dlpar_workqueue_init() == 0)
                        request_event_sources_irqs(np, ras_hotplug_interrupt,
                                                   "RAS_HOTPLUG");
                of_node_put(np);
        }

        return 0;
}
machine_late_initcall(pseries, init_ras_hotplug_IRQ);

/*
 * Initialize handlers for the set of interrupts caused by hardware errors
 * and power system events.
 */
static int __init init_ras_IRQ(void)
{
        struct device_node *np;

        ras_check_exception_token = rtas_token("check-exception");

        /* Internal Errors */
        np = of_find_node_by_path("/event-sources/internal-errors");
        if (np != NULL) {
                request_event_sources_irqs(np, ras_error_interrupt,
                                           "RAS_ERROR");
                of_node_put(np);
        }

        /* EPOW Events */
        np = of_find_node_by_path("/event-sources/epow-events");
        if (np != NULL) {
                request_event_sources_irqs(np, ras_epow_interrupt, "RAS_EPOW");
                of_node_put(np);
        }

        return 0;
}
machine_subsys_initcall(pseries, init_ras_IRQ);

#define EPOW_SHUTDOWN_NORMAL                            1
#define EPOW_SHUTDOWN_ON_UPS                            2
#define EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS        3
#define EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH      4

static void handle_system_shutdown(char event_modifier)
{
        switch (event_modifier) {
        case EPOW_SHUTDOWN_NORMAL:
                pr_emerg("Power off requested\n");
                orderly_poweroff(true);
                break;

        case EPOW_SHUTDOWN_ON_UPS:
                pr_emerg("Loss of system power detected. System is running on"
                         " UPS/battery. Check RTAS error log for details\n");
                orderly_poweroff(true);
                break;

        case EPOW_SHUTDOWN_LOSS_OF_CRITICAL_FUNCTIONS:
                pr_emerg("Loss of system critical functions detected. Check"
                         " RTAS error log for details\n");
                orderly_poweroff(true);
                break;

        case EPOW_SHUTDOWN_AMBIENT_TEMPERATURE_TOO_HIGH:
                pr_emerg("High ambient temperature detected. Check RTAS"
                         " error log for details\n");
                orderly_poweroff(true);
                break;

        default:
                pr_err("Unknown power/cooling shutdown event (modifier = %d)\n",
                        event_modifier);
        }
}

struct epow_errorlog {
        unsigned char sensor_value;
        unsigned char event_modifier;
        unsigned char extended_modifier;
        unsigned char reserved;
        unsigned char platform_reason;
};

#define EPOW_RESET                      0
#define EPOW_WARN_COOLING               1
#define EPOW_WARN_POWER                 2
#define EPOW_SYSTEM_SHUTDOWN            3
#define EPOW_SYSTEM_HALT                4
#define EPOW_MAIN_ENCLOSURE             5
#define EPOW_POWER_OFF                  7

static void rtas_parse_epow_errlog(struct rtas_error_log *log)
{
        struct pseries_errorlog *pseries_log;
        struct epow_errorlog *epow_log;
        char action_code;
        char modifier;

        pseries_log = get_pseries_errorlog(log, PSERIES_ELOG_SECT_ID_EPOW);
        if (pseries_log == NULL)
                return;

        epow_log = (struct epow_errorlog *)pseries_log->data;
        action_code = epow_log->sensor_value & 0xF;     /* bottom 4 bits */
        modifier = epow_log->event_modifier & 0xF;      /* bottom 4 bits */

        switch (action_code) {
        case EPOW_RESET:
                if (num_epow_events) {
                        pr_info("Non critical power/cooling issue cleared\n");
                        num_epow_events--;
                }
                break;

        case EPOW_WARN_COOLING:
                pr_info("Non-critical cooling issue detected. Check RTAS error"
                        " log for details\n");
                break;

        case EPOW_WARN_POWER:
                pr_info("Non-critical power issue detected. Check RTAS error"
                        " log for details\n");
                break;

        case EPOW_SYSTEM_SHUTDOWN:
                handle_system_shutdown(epow_log->event_modifier);
                break;

        case EPOW_SYSTEM_HALT:
                pr_emerg("Critical power/cooling issue detected. Check RTAS"
                         " error log for details. Powering off.\n");
                orderly_poweroff(true);
                break;

        case EPOW_MAIN_ENCLOSURE:
        case EPOW_POWER_OFF:
                pr_emerg("System about to lose power. Check RTAS error log "
                         " for details. Powering off immediately.\n");
                emergency_sync();
                kernel_power_off();
                break;

        default:
                pr_err("Unknown power/cooling event (action code  = %d)\n",
                        action_code);
        }

        /* Increment epow events counter variable */
        if (action_code != EPOW_RESET)
                num_epow_events++;
}

static irqreturn_t ras_hotplug_interrupt(int irq, void *dev_id)
{
        struct pseries_errorlog *pseries_log;
        struct pseries_hp_errorlog *hp_elog;

        spin_lock(&ras_log_buf_lock);

        rtas_call(ras_check_exception_token, 6, 1, NULL,
                  RTAS_VECTOR_EXTERNAL_INTERRUPT, virq_to_hw(irq),
                  RTAS_HOTPLUG_EVENTS, 0, __pa(&ras_log_buf),
                  rtas_get_error_log_max());

        pseries_log = get_pseries_errorlog((struct rtas_error_log *)ras_log_buf,
                                           PSERIES_ELOG_SECT_ID_HOTPLUG);
        hp_elog = (struct pseries_hp_errorlog *)pseries_log->data;

        /*
         * Since PCI hotplug is not currently supported on pseries, put PCI
         * hotplug events on the ras_log_buf to be handled by rtas_errd.
         */
        if (hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_MEM ||
            hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_CPU ||
            hp_elog->resource == PSERIES_HP_ELOG_RESOURCE_PMEM)
                queue_hotplug_event(hp_elog);
        else
                log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

        spin_unlock(&ras_log_buf_lock);
        return IRQ_HANDLED;
}

/* Handle environmental and power warning (EPOW) interrupts. */
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
{
        int status;
        int state;
        int critical;

        status = rtas_get_sensor_fast(EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX,
                                      &state);

        if (state > 3)
                critical = 1;           /* Time Critical */
        else
                critical = 0;

        spin_lock(&ras_log_buf_lock);

        status = rtas_call(ras_check_exception_token, 6, 1, NULL,
                           RTAS_VECTOR_EXTERNAL_INTERRUPT,
                           virq_to_hw(irq),
                           RTAS_EPOW_WARNING,
                           critical, __pa(&ras_log_buf),
                                rtas_get_error_log_max());

        log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

        rtas_parse_epow_errlog((struct rtas_error_log *)ras_log_buf);

        spin_unlock(&ras_log_buf_lock);
        return IRQ_HANDLED;
}

/*
 * Handle hardware error interrupts.
 *
 * RTAS check-exception is called to collect data on the exception.  If
 * the error is deemed recoverable, we log a warning and return.
 * For nonrecoverable errors, an error is logged and we stop all processing
 * as quickly as possible in order to prevent propagation of the failure.
 */
static irqreturn_t ras_error_interrupt(int irq, void *dev_id)
{
        struct rtas_error_log *rtas_elog;
        int status;
        int fatal;

        spin_lock(&ras_log_buf_lock);

        status = rtas_call(ras_check_exception_token, 6, 1, NULL,
                           RTAS_VECTOR_EXTERNAL_INTERRUPT,
                           virq_to_hw(irq),
                           RTAS_INTERNAL_ERROR, 1 /* Time Critical */,
                           __pa(&ras_log_buf),
                                rtas_get_error_log_max());

        rtas_elog = (struct rtas_error_log *)ras_log_buf;

        if (status == 0 &&
            rtas_error_severity(rtas_elog) >= RTAS_SEVERITY_ERROR_SYNC)
                fatal = 1;
        else
                fatal = 0;

        /* format and print the extended information */
        log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, fatal);

        if (fatal) {
                pr_emerg("Fatal hardware error detected. Check RTAS error"
                         " log for details. Powering off immediately\n");
                emergency_sync();
                kernel_power_off();
        } else {
                pr_err("Recoverable hardware error detected\n");
        }

        spin_unlock(&ras_log_buf_lock);
        return IRQ_HANDLED;
}

/*
 * Some versions of FWNMI place the buffer inside the 4kB page starting at
 * 0x7000. Other versions place it inside the rtas buffer. We check both.
 */
#define VALID_FWNMI_BUFFER(A) \
        ((((A) >= 0x7000) && ((A) < 0x7ff0)) || \
        (((A) >= rtas.base) && ((A) < (rtas.base + rtas.size - 16))))

static inline struct rtas_error_log *fwnmi_get_errlog(void)
{
        return (struct rtas_error_log *)local_paca->mce_data_buf;
}

/*
 * Get the error information for errors coming through the
 * FWNMI vectors.  The pt_regs' r3 will be updated to reflect
 * the actual r3 if possible, and a ptr to the error log entry
 * will be returned if found.
 *
 * Use one buffer mce_data_buf per cpu to store RTAS error.
 *
 * The mce_data_buf does not have any locks or protection around it,
 * if a second machine check comes in, or a system reset is done
 * before we have logged the error, then we will get corruption in the
 * error log.  This is preferable over holding off on calling
 * ibm,nmi-interlock which would result in us checkstopping if a
 * second machine check did come in.
 */
static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
{
        unsigned long *savep;
        struct rtas_error_log *h;

        /* Mask top two bits */
        regs->gpr[3] &= ~(0x3UL << 62);

        if (!VALID_FWNMI_BUFFER(regs->gpr[3])) {
                printk(KERN_ERR "FWNMI: corrupt r3 0x%016lx\n", regs->gpr[3]);
                return NULL;
        }

        savep = __va(regs->gpr[3]);
        regs->gpr[3] = be64_to_cpu(savep[0]);   /* restore original r3 */

        h = (struct rtas_error_log *)&savep[1];
        /* Use the per cpu buffer from paca to store rtas error log */
        memset(local_paca->mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
        if (!rtas_error_extended(h)) {
                memcpy(local_paca->mce_data_buf, h, sizeof(__u64));
        } else {
                int len, error_log_length;

                error_log_length = 8 + rtas_error_extended_log_length(h);
                len = min_t(int, error_log_length, RTAS_ERROR_LOG_MAX);
                memcpy(local_paca->mce_data_buf, h, len);
        }

        return (struct rtas_error_log *)local_paca->mce_data_buf;
}

/* Call this when done with the data returned by FWNMI_get_errinfo.
 * It will release the saved data area for other CPUs in the
 * partition to receive FWNMI errors.
 */
static void fwnmi_release_errinfo(void)
{
        int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
        if (ret != 0)
                printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
}

int pSeries_system_reset_exception(struct pt_regs *regs)
{
#ifdef __LITTLE_ENDIAN__
        /*
         * Some firmware byteswaps SRR registers and gives incorrect SRR1. Try
         * to detect the bad SRR1 pattern here. Flip the NIP back to correct
         * endian for reporting purposes. Unfortunately the MSR can't be fixed,
         * so clear it. It will be missing MSR_RI so we won't try to recover.
         */
        if ((be64_to_cpu(regs->msr) &
                        (MSR_LE|MSR_RI|MSR_DR|MSR_IR|MSR_ME|MSR_PR|
                         MSR_ILE|MSR_HV|MSR_SF)) == (MSR_DR|MSR_SF)) {
                regs->nip = be64_to_cpu((__be64)regs->nip);
                regs->msr = 0;
        }
#endif

        if (fwnmi_active) {
                struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
                if (errhdr) {
                        /* XXX Should look at FWNMI information */
                }
                fwnmi_release_errinfo();
        }

        if (smp_handle_nmi_ipi(regs))
                return 1;

        return 0; /* need to perform reset */
}

#define VAL_TO_STRING(ar, val)  \
        (((val) < ARRAY_SIZE(ar)) ? ar[(val)] : "Unknown")

static void pseries_print_mce_info(struct pt_regs *regs,
                                   struct rtas_error_log *errp)
{
        const char *level, *sevstr;
        struct pseries_errorlog *pseries_log;
        struct pseries_mc_errorlog *mce_log;
        u8 error_type, err_sub_type;
        u64 addr;
        u8 initiator = rtas_error_initiator(errp);
        int disposition = rtas_error_disposition(errp);

        static const char * const initiators[] = {
                [0] = "Unknown",
                [1] = "CPU",
                [2] = "PCI",
                [3] = "ISA",
                [4] = "Memory",
                [5] = "Power Mgmt",
        };
        static const char * const mc_err_types[] = {
                [0] = "UE",
                [1] = "SLB",
                [2] = "ERAT",
                [3] = "Unknown",
                [4] = "TLB",
                [5] = "D-Cache",
                [6] = "Unknown",
                [7] = "I-Cache",
        };
        static const char * const mc_ue_types[] = {
                [0] = "Indeterminate",
                [1] = "Instruction fetch",
                [2] = "Page table walk ifetch",
                [3] = "Load/Store",
                [4] = "Page table walk Load/Store",
        };

        /* SLB sub errors valid values are 0x0, 0x1, 0x2 */
        static const char * const mc_slb_types[] = {
                [0] = "Parity",
                [1] = "Multihit",
                [2] = "Indeterminate",
        };

        /* TLB and ERAT sub errors valid values are 0x1, 0x2, 0x3 */
        static const char * const mc_soft_types[] = {
                [0] = "Unknown",
                [1] = "Parity",
                [2] = "Multihit",
                [3] = "Indeterminate",
        };

        if (!rtas_error_extended(errp)) {
                pr_err("Machine check interrupt: Missing extended error log\n");
                return;
        }

        pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
        if (pseries_log == NULL)
                return;

        mce_log = (struct pseries_mc_errorlog *)pseries_log->data;

        error_type = mce_log->error_type;
        err_sub_type = rtas_mc_error_sub_type(mce_log);

        switch (rtas_error_severity(errp)) {
        case RTAS_SEVERITY_NO_ERROR:
                level = KERN_INFO;
                sevstr = "Harmless";
                break;
        case RTAS_SEVERITY_WARNING:
                level = KERN_WARNING;
                sevstr = "";
                break;
        case RTAS_SEVERITY_ERROR:
        case RTAS_SEVERITY_ERROR_SYNC:
                level = KERN_ERR;
                sevstr = "Severe";
                break;
        case RTAS_SEVERITY_FATAL:
        default:
                level = KERN_ERR;
                sevstr = "Fatal";
                break;
        }

#ifdef CONFIG_PPC_BOOK3S_64
        /* Display faulty slb contents for SLB errors. */
        if (error_type == MC_ERROR_TYPE_SLB)
                slb_dump_contents(local_paca->mce_faulty_slbs);
#endif

        printk("%s%s Machine check interrupt [%s]\n", level, sevstr,
               disposition == RTAS_DISP_FULLY_RECOVERED ?
               "Recovered" : "Not recovered");
        if (user_mode(regs)) {
                printk("%s  NIP: [%016lx] PID: %d Comm: %s\n", level,
                       regs->nip, current->pid, current->comm);
        } else {
                printk("%s  NIP [%016lx]: %pS\n", level, regs->nip,
                       (void *)regs->nip);
        }
        printk("%s  Initiator: %s\n", level,
               VAL_TO_STRING(initiators, initiator));

        switch (error_type) {
        case MC_ERROR_TYPE_UE:
                printk("%s  Error type: %s [%s]\n", level,
                       VAL_TO_STRING(mc_err_types, error_type),
                       VAL_TO_STRING(mc_ue_types, err_sub_type));
                break;
        case MC_ERROR_TYPE_SLB:
                printk("%s  Error type: %s [%s]\n", level,
                       VAL_TO_STRING(mc_err_types, error_type),
                       VAL_TO_STRING(mc_slb_types, err_sub_type));
                break;
        case MC_ERROR_TYPE_ERAT:
        case MC_ERROR_TYPE_TLB:
                printk("%s  Error type: %s [%s]\n", level,
                       VAL_TO_STRING(mc_err_types, error_type),
                       VAL_TO_STRING(mc_soft_types, err_sub_type));
                break;
        default:
                printk("%s  Error type: %s\n", level,
                       VAL_TO_STRING(mc_err_types, error_type));
                break;
        }

        addr = rtas_mc_get_effective_addr(mce_log);
        if (addr)
                printk("%s    Effective address: %016llx\n", level, addr);
}

static int mce_handle_error(struct rtas_error_log *errp)
{
        struct pseries_errorlog *pseries_log;
        struct pseries_mc_errorlog *mce_log;
        int disposition = rtas_error_disposition(errp);
        u8 error_type;

        if (!rtas_error_extended(errp))
                goto out;

        pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
        if (pseries_log == NULL)
                goto out;

        mce_log = (struct pseries_mc_errorlog *)pseries_log->data;
        error_type = mce_log->error_type;

#ifdef CONFIG_PPC_BOOK3S_64
        if (disposition == RTAS_DISP_NOT_RECOVERED) {
                switch (error_type) {
                case    MC_ERROR_TYPE_SLB:
                case    MC_ERROR_TYPE_ERAT:
                        /*
                         * Store the old slb content in paca before flushing.
                         * Print this when we go to virtual mode.
                         * There are chances that we may hit MCE again if there
                         * is a parity error on the SLB entry we trying to read
                         * for saving. Hence limit the slb saving to single
                         * level of recursion.
                         */
                        if (local_paca->in_mce == 1)
                                slb_save_contents(local_paca->mce_faulty_slbs);
                        flush_and_reload_slb();
                        disposition = RTAS_DISP_FULLY_RECOVERED;
                        rtas_set_disposition_recovered(errp);
                        break;
                default:
                        break;
                }
        }
#endif

out:
        return disposition;
}

#ifdef CONFIG_MEMORY_FAILURE

static DEFINE_PER_CPU(int, rtas_ue_count);
static DEFINE_PER_CPU(unsigned long, rtas_ue_paddr[MAX_MC_EVT]);

#define UE_EFFECTIVE_ADDR_PROVIDED      0x40
#define UE_LOGICAL_ADDR_PROVIDED        0x20


static void pseries_hwpoison_work_fn(struct work_struct *work)
{
        unsigned long paddr;
        int index;

        while (__this_cpu_read(rtas_ue_count) > 0) {
                index = __this_cpu_read(rtas_ue_count) - 1;
                paddr = __this_cpu_read(rtas_ue_paddr[index]);
                memory_failure(paddr >> PAGE_SHIFT, 0);
                __this_cpu_dec(rtas_ue_count);
        }
}

static DECLARE_WORK(hwpoison_work, pseries_hwpoison_work_fn);

static void queue_ue_paddr(unsigned long paddr)
{
        int index;

        index = __this_cpu_inc_return(rtas_ue_count) - 1;
        if (index >= MAX_MC_EVT) {
                __this_cpu_dec(rtas_ue_count);
                return;
        }
        this_cpu_write(rtas_ue_paddr[index], paddr);
        schedule_work(&hwpoison_work);
}

static void pseries_do_memory_failure(struct pt_regs *regs,
                                      struct pseries_mc_errorlog *mce_log)
{
        unsigned long paddr;

        if (mce_log->sub_err_type & UE_LOGICAL_ADDR_PROVIDED) {
                paddr = be64_to_cpu(mce_log->logical_address);
        } else if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED) {
                unsigned long pfn;

                pfn = addr_to_pfn(regs,
                                  be64_to_cpu(mce_log->effective_address));
                if (pfn == ULONG_MAX)
                        return;
                paddr = pfn << PAGE_SHIFT;
        } else {
                return;
        }
        queue_ue_paddr(paddr);
}

static void pseries_process_ue(struct pt_regs *regs,
                               struct rtas_error_log *errp)
{
        struct pseries_errorlog *pseries_log;
        struct pseries_mc_errorlog *mce_log;

        if (!rtas_error_extended(errp))
                return;

        pseries_log = get_pseries_errorlog(errp, PSERIES_ELOG_SECT_ID_MCE);
        if (!pseries_log)
                return;

        mce_log = (struct pseries_mc_errorlog *)pseries_log->data;

        if (mce_log->error_type == MC_ERROR_TYPE_UE)
                pseries_do_memory_failure(regs, mce_log);
}
#else
static inline void pseries_process_ue(struct pt_regs *regs,
                                      struct rtas_error_log *errp) { }
#endif /*CONFIG_MEMORY_FAILURE */

/*
 * Process MCE rtas errlog event.
 */
static void mce_process_errlog_event(struct irq_work *work)
{
        struct rtas_error_log *err;

        err = fwnmi_get_errlog();
        log_error((char *)err, ERR_TYPE_RTAS_LOG, 0);
}

/*
 * See if we can recover from a machine check exception.
 * This is only called on power4 (or above) and only via
 * the Firmware Non-Maskable Interrupts (fwnmi) handler
 * which provides the error analysis for us.
 *
 * Return 1 if corrected (or delivered a signal).
 * Return 0 if there is nothing we can do.
 */
static int recover_mce(struct pt_regs *regs, struct rtas_error_log *err)
{
        int recovered = 0;
        int disposition = rtas_error_disposition(err);

        pseries_print_mce_info(regs, err);

        if (!(regs->msr & MSR_RI)) {
                /* If MSR_RI isn't set, we cannot recover */
                pr_err("Machine check interrupt unrecoverable: MSR(RI=0)\n");
                recovered = 0;

        } else if (disposition == RTAS_DISP_FULLY_RECOVERED) {
                /* Platform corrected itself */
                recovered = 1;

        } else if (disposition == RTAS_DISP_LIMITED_RECOVERY) {
                /* Platform corrected itself but could be degraded */
                printk(KERN_ERR "MCE: limited recovery, system may "
                       "be degraded\n");
                recovered = 1;

        } else if (user_mode(regs) && !is_global_init(current) &&
                   rtas_error_severity(err) == RTAS_SEVERITY_ERROR_SYNC) {

                /*
                 * If we received a synchronous error when in userspace
                 * kill the task. Firmware may report details of the fail
                 * asynchronously, so we can't rely on the target and type
                 * fields being valid here.
                 */
                printk(KERN_ERR "MCE: uncorrectable error, killing task "
                       "%s:%d\n", current->comm, current->pid);

                _exception(SIGBUS, regs, BUS_MCEERR_AR, regs->nip);
                recovered = 1;
        }

        pseries_process_ue(regs, err);

        /* Queue irq work to log this rtas event later. */
        irq_work_queue(&mce_errlog_process_work);

        return recovered;
}

/*
 * Handle a machine check.
 *
 * Note that on Power 4 and beyond Firmware Non-Maskable Interrupts (fwnmi)
 * should be present.  If so the handler which called us tells us if the
 * error was recovered (never true if RI=0).
 *
 * On hardware prior to Power 4 these exceptions were asynchronous which
 * means we can't tell exactly where it occurred and so we can't recover.
 */
int pSeries_machine_check_exception(struct pt_regs *regs)
{
        struct rtas_error_log *errp;

        if (fwnmi_active) {
                fwnmi_release_errinfo();
                errp = fwnmi_get_errlog();
                if (errp && recover_mce(regs, errp))
                        return 1;
        }

        return 0;
}

long pseries_machine_check_realmode(struct pt_regs *regs)
{
        struct rtas_error_log *errp;
        int disposition;

        if (fwnmi_active) {
                errp = fwnmi_get_errinfo(regs);
                /*
                 * Call to fwnmi_release_errinfo() in real mode causes kernel
                 * to panic. Hence we will call it as soon as we go into
                 * virtual mode.
                 */
                disposition = mce_handle_error(errp);
                if (disposition == RTAS_DISP_FULLY_RECOVERED)
                        return 1;
        }

        return 0;
}