text: /*
   * 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/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);
  
  static 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
  
  static irqreturn_t ras_epow_interrupt(int irq, void *dev_id);
  static irqreturn_t ras_error_interrupt(int irq, void *dev_id);
  
  
  /*
   * 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_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;
  }
  __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,
  			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
  			   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,
  			   RTAS_VECTOR_EXTERNAL_INTERRUPT,
  			   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_RTAS_POWER_OFF
  		/* 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) {
  		}
  		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);
  		_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;
  }
  