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ras.c

/*
 * Copyright (C) 2001 Dave Engebretsen IBM Corporation
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 */

/* Change Activity:
 * 2001/09/21 : engebret : Created with minimal EPOW and HW exception support.
 * End Change Activity
 */

#include <linux/errno.h>
#include <linux/threads.h>
#include <linux/kernel_stat.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/irq.h>
#include <linux/random.h>
#include <linux/sysrq.h>
#include <linux/bitops.h>

#include <asm/uaccess.h>
#include <asm/system.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/irq.h>
#include <asm/cache.h>
#include <asm/prom.h>
#include <asm/ptrace.h>
#include <asm/machdep.h>
#include <asm/rtas.h>
#include <asm/udbg.h>
#include <asm/firmware.h>

#include "pseries.h"

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

char mce_data_buf[RTAS_ERROR_LOG_MAX];

static int ras_get_sensor_state_token;
static int ras_check_exception_token;

#define EPOW_SENSOR_TOKEN     9
#define EPOW_SENSOR_INDEX     0
#define RAS_VECTOR_OFFSET     0x500

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

/* #define DEBUG */


static void request_ras_irqs(struct device_node *np,
                  irq_handler_t handler,
                  const char *name)
{
      int i, index, count = 0;
      struct of_irq oirq;
      const u32 *opicprop;
      unsigned int opicplen;
      unsigned int virqs[16];

      /* Check for obsolete "open-pic-interrupt" property. If present, then
       * map those interrupts using the default interrupt host and default
       * trigger
       */
      opicprop = of_get_property(np, "open-pic-interrupt", &opicplen);
      if (opicprop) {
            opicplen /= sizeof(u32);
            for (i = 0; i < opicplen; i++) {
                  if (count > 15)
                        break;
                  virqs[count] = irq_create_mapping(NULL, *(opicprop++));
                  if (virqs[count] == NO_IRQ)
                        printk(KERN_ERR "Unable to allocate interrupt "
                               "number for %s\n", np->full_name);
                  else
                        count++;

            }
      }
      /* Else use normal interrupt tree parsing */
      else {
            /* First try to do a proper OF tree parsing */
            for (index = 0; of_irq_map_one(np, index, &oirq) == 0;
                 index++) {
                  if (count > 15)
                        break;
                  virqs[count] = irq_create_of_mapping(oirq.controller,
                                              oirq.specifier,
                                              oirq.size);
                  if (virqs[count] == NO_IRQ)
                        printk(KERN_ERR "Unable to allocate interrupt "
                               "number for %s\n", np->full_name);
                  else
                        count++;
            }
      }

      /* Now request them */
      for (i = 0; i < count; i++) {
            if (request_irq(virqs[i], handler, 0, name, NULL)) {
                  printk(KERN_ERR "Unable to request interrupt %d for "
                         "%s\n", virqs[i], np->full_name);
                  return;
            }
      }
}

/*
 * 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_get_sensor_state_token = rtas_token("get-sensor-state");
      ras_check_exception_token = rtas_token("check-exception");

      /* Internal Errors */
      np = of_find_node_by_path("/event-sources/internal-errors");
      if (np != NULL) {
            request_ras_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_ras_irqs(np, ras_epow_interrupt, "RAS_EPOW");
            of_node_put(np);
      }

      return 0;
}
__initcall(init_ras_IRQ);

/*
 * Handle power subsystem events (EPOW).
 *
 * Presently we just log the event has occurred.  This should be fixed
 * to examine the type of power failure and take appropriate action where
 * the time horizon permits something useful to be done.
 */
static irqreturn_t ras_epow_interrupt(int irq, void *dev_id)
{
      int status = 0xdeadbeef;
      int state = 0;
      int critical;

      status = rtas_call(ras_get_sensor_state_token, 2, 2, &state,
                     EPOW_SENSOR_TOKEN, EPOW_SENSOR_INDEX);

      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,
                     RAS_VECTOR_OFFSET,
                     irq_map[irq].hwirq,
                     RTAS_EPOW_WARNING | RTAS_POWERMGM_EVENTS,
                     critical, __pa(&ras_log_buf),
                        rtas_get_error_log_max());

      udbg_printf("EPOW <0x%lx 0x%x 0x%x>\n",
                *((unsigned long *)&ras_log_buf), status, state);
      printk(KERN_WARNING "EPOW <0x%lx 0x%x 0x%x>\n",
             *((unsigned long *)&ras_log_buf), status, state);

      /* format and print the extended information */
      log_error(ras_log_buf, ERR_TYPE_RTAS_LOG, 0);

      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 = 0xdeadbeef;
      int fatal;

      spin_lock(&ras_log_buf_lock);

      status = rtas_call(ras_check_exception_token, 6, 1, NULL,
                     RAS_VECTOR_OFFSET,
                     irq_map[irq].hwirq,
                     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_elog->severity >= 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) {
            udbg_printf("Fatal HW Error <0x%lx 0x%x>\n",
                      *((unsigned long *)&ras_log_buf), status);
            printk(KERN_EMERG "Error: Fatal hardware error <0x%lx 0x%x>\n",
                   *((unsigned long *)&ras_log_buf), status);

#ifndef DEBUG
            /* Don't actually power off when debugging so we can test
             * without actually failing while injecting errors.
             * Error data will not be logged to syslog.
             */
            ppc_md.power_off();
#endif
      } else {
            udbg_printf("Recoverable HW Error <0x%lx 0x%x>\n",
                      *((unsigned long *)&ras_log_buf), status);
            printk(KERN_WARNING
                   "Warning: Recoverable hardware error <0x%lx 0x%x>\n",
                   *((unsigned long *)&ras_log_buf), status);
      }

      spin_unlock(&ras_log_buf_lock);
      return IRQ_HANDLED;
}

/* 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.
 *
 * 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 errdata = regs->gpr[3];
      struct rtas_error_log *errhdr = NULL;
      unsigned long *savep;

      if ((errdata >= 0x7000 && errdata < 0x7fff0) ||
          (errdata >= rtas.base && errdata < rtas.base + rtas.size - 16)) {
            savep = __va(errdata);
            regs->gpr[3] = savep[0];      /* restore original r3 */
            memset(mce_data_buf, 0, RTAS_ERROR_LOG_MAX);
            memcpy(mce_data_buf, (char *)(savep + 1), RTAS_ERROR_LOG_MAX);
            errhdr = (struct rtas_error_log *)mce_data_buf;
      } else {
            printk("FWNMI: corrupt r3\n");
      }
      return errhdr;
}

/* 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("FWNMI: nmi-interlock failed: %d\n", ret);
}

int pSeries_system_reset_exception(struct pt_regs *regs)
{
      if (fwnmi_active) {
            struct rtas_error_log *errhdr = fwnmi_get_errinfo(regs);
            if (errhdr) {
                  /* XXX Should look at FWNMI information */
            }
            fwnmi_release_errinfo();
      }
      return 0; /* need to perform reset */
}

/*
 * 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 nonfatal = 0;

      if (err->disposition == RTAS_DISP_FULLY_RECOVERED) {
            /* Platform corrected itself */
            nonfatal = 1;
      } else if ((regs->msr & MSR_RI) &&
               user_mode(regs) &&
               err->severity == RTAS_SEVERITY_ERROR_SYNC &&
               err->disposition == RTAS_DISP_NOT_RECOVERED &&
               err->target == RTAS_TARGET_MEMORY &&
               err->type == RTAS_TYPE_ECC_UNCORR &&
               !(current->pid == 0 || is_global_init(current))) {
            /* Kill off a user process with an ECC error */
            printk(KERN_ERR "MCE: uncorrectable ecc error for pid %d\n",
                   current->pid);
            /* XXX something better for ECC error? */
            _exception(SIGBUS, regs, BUS_ADRERR, regs->nip);
            nonfatal = 1;
      }

      log_error((char *)err, ERR_TYPE_RTAS_LOG, !nonfatal);

      return nonfatal;
}

/*
 * 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) {
            errp = fwnmi_get_errinfo(regs);
            fwnmi_release_errinfo();
            if (errp && recover_mce(regs, errp))
                  return 1;
      }

      return 0;
}

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